Publications

Dynamic penetrometer is a worldwide practice in geotechnical exploration and the French Panda®(1) lightweight variable energy is the most developed device nowadays. Widely used in France and other countries, The Panda penetrometer is relatively unknown for characterizing surface soils domain and the possibilities it offers. In this Article, the authors offer a brief review of the principle of measurement, its uses, advantages and disadvantages calibration, and interpretation, as well as the different relationships with other in-situ test (CPT, SPT…) and some geotechnical parameters. A summary of the works that can be found and that are based on this technology is also presented. The overall aim is to provide the reader with a basic historical document for a better understanding of the operation and analysis of the results obtained with this device, enabling it to be integrated, as a complement, into in situ investigation campaigns.

Dynamic penetration tests DPT have been routinely employed in the geotechnical characterization of thesubsoil in different types of engineering projects. The evaluation of the results of these tests has been performed consideringa limited number of parameters obtained in the field, so the definition of new parameters allows a more accurate evaluationof soil characteristics. The purpose of this paper is to present a methodology for the evaluation of the dynamic modulus(Ekd) based on the analysis of the dynamic force and velocity signals recorded in each hammer impact. Variable energyDPT tests were performed on Fontainebleau NE34 sand specimens in a K0 calibration chamber. For each hammer impacton the penetrometer, a decoupling and wave reconstruction method was applied to obtain the force and velocity signals atthe cone-soil interface, which are analyzed in the frequency spectrum to obtain the Ekd modulus. The results show that it ispossible to evaluate the dynamic modulus at different vertical loading conditions and independent of the impact energy levelof the hammer on the penetrometer.

Dynamic penetration tests (DPT) are largely applied for soil in situ characterization. Cone resistance assessment from DPT isusually based on driving formulas derived from Newtonian approach. These are nevertheless often considered inaccurate and unable to fullydescribe dynamic penetration phenomenon. Wave equation approach provides a more rigorous analysis but remains less common for practicalreasons (requiring instrumentation and a more complex analysis). Historically, driving formulas derived from Newtonian approach are oftenpreferred for its simplicity. Thus, these formulas still play a major role in DPT interpretation and their use is recommended by currentstandards. It is important to evaluate different methods derived from wave equation and also to verify if a simple approach, such as Dutchformula (DF), combined with good practice (e.g., energy measurement, skin friction control) can produce satisfactory results. For that,laboratory and field tests were performed employing instrumented dynamic penetrometers (a lightweight and a super-heavy dynamic penetrometer).The main contribution of this paper is demonstrating the importance of method applied when determining resistance from DPTand providing comparison between common methods when testing different type of soils. Results showed that on average DF results werecomparable to those from cone penetration test (CPT) resistance (diverging by no more than 15%). Wave equation methods results werecomparable (
30%) to CPT cone resistance in most cases when testing shallower nonplastic layers. CASE method underestimated by morethan 50% the resistance for shallower layers. DF including energy measurements produce lower results than all methods examined and up to50% inferior to CPT. This work shows that, for shallow soils, DF method does not produce less accurate for assessment of soil resistance thatwave equation-based methods. Other key aspect brought to light is that wave equation-based methods considerably overestimated resistancein deeper plastic saturated layers which suggests that skin friction correction application should also be considered in such conditions forthese methods. When only unsaturated zones are considered, these methods tend to underestimate resistance: Simplified method and tip forceintegration method produced results 18% and 24% inferior to CPT whereas DF with energy measurement and other wave equation methodssignificantly underestimated resistance (on more than 40%).

The degradation of the substructure plays a crucial role in the geometric deterioration of railway track. The condition of the substructure is evaluated by means of geotechnical diagnostics that consider various parameters, among which the geotechnical layer model stands out (Basye et al., 2020). The accuracy in the determination of this model is essential, since it significantly influences decision making and ensures the efficiency of the measures taken. In this study, data fusion is proposed to reduce the uncertainty and increase the reliability of the geotechnical layer model of the substructure. This technique combines different types of data and monitoring results, integrating geotechnical indicators (Pandoscope®) and volumetric geophysical measurements (Ground penetration radar - GPR). The results show that data fusion increases the accuracy of the geotechnical model, improving decision making in railway maintenance.

Railway tracks, like all civil works, experience degradation after being put into service, thus losing their initial design conditions. This degradation manifests itself mainly through misalignment and specific deterioration mechanisms of each component, which reduces safety and comfort during the passage of trains. In order to maintain their operational capabilities or prolong their service life, continuous monitoring, diagnosis and maintenance processes are carried out. These actions aim to restore the physical, mechanical and geometrical properties necessary for track operation. In practice, rail managers often employ hegemonic techniques such as geometric measurements to detect defects and routine maintenance to realign, known as tamping. Although these practices have proven to be effective, in some cases they do not technically and economically competently solve the root problem. For this reason, diagnosis should be multidisciplinary and incorporate various disciplines associated with the track components. This paper aims to highlight the importance and impact of geotechnical diagnosis in the management of railway networks. To achieve this, the Article has the following structure: (a) Railway track components: the main elements of the track are described and the role of geotechnical components in the stability of the infrastructure is highlighted, (b) Track degradation: The main deterioration of the track, such as loss of geometry, and its relation to the wear of the geotechnical elements are addressed, (c) Monitoring and monitoring: the most commonly used geotechnical inspection methods and their effectiveness in the analysis of granular material are presented, (d) Geotechnical diagnosis: Current maintenance management is analyzed and guidelines for a comprehensive diagnosis are suggested, highlighting cases where poor assessment has generated problems, (e) Maintenance techniques: Preservation methods are reviewed, stressing the importance of accurate diagnosis for their effectiveness, and (f) Future perspectives: Trends such as the use of artificial intelligence and advanced data management in the railway sector are explored.

In the context of railways, it is essential to have a reliable ground model to ensure their safety and smooth operation. To achieve this, geophysical monitoring, and geotechnical techniques, are often used. However, effectively combining geophysical and geotechnical data remains a challenge. In this study, a methodology based on data fusion of Ground Penetrating Radar (GPR) and Pandoscope data and based on belief functions is proposed in order to define the ground model of the railway substructure. The fusion of these data using Smets, Dempster-Shafer and PCR6 normalization rules allows to improve the character-ization of horizontal interfaces and to achieve an accurate assessment of the sub-surface conditions on railway tracks.

Although ballast layer can be characterized by different parameters, the literature notes the absence of global performance indicators of ballast in ser-vice. This Article presents a methodology that proposed to obtain local perfor-mance indicators (based on the functions performed by the ballast layer) and global performance indicators (based on the combination of the above). The pro-posed methodology consists of three phases: (i) the first is the performance of a functional analysis (FA) for the identification of the key functions of the ballast layer, (ii) application of the failure mode and effects analysis (FMEA) for the creation of the failure trees of the functions identified in the previous phase and (iii) application of data aggregation to combine the parameters and indicators in the form of a model to obtain the performance indicators. The results of perfor-mance indicators can be useful for the planning of corrective actions and in case of failures or defects to identify their causes. The methodology allows adapting the conditions and/or needs of each railway manager by modifying the failure modes and modifying the scales proposed for data aggregation.

Coastal beach and dune ecosystems are critically important for shoreline protection and significant resources have been allocated to their conservation. Dune vegetation is known to modify site response to wind, waves, and storms, but little focus has been given to understanding how belowground sediment structures enhance dune stability. A first step in addressing this knowledge gap is to determine optimal methods to measure subsurface sediment properties in onshore sandy environments. Our team performed a comparison of geotechnical and geophysical methods on a restored beach and dune system on Florida’s Atlantic coast. Methods included two types of dynamic cone penetrometer (DCP) systems, a multi-channel analysis of surface wave (MASW) system, a ground penetrating radar (GPR), soil vibracores, and grain size analyses. Two transects were investigated, a 50-meter cross-shore transect and an intersecting 20-meter along-shore transect. The transects were selected to study the gradient of sediment properties from the swash zone to the high dune. Key findings from this study were that the PANDA DCP provided a higher resolution of measurements compared to the standard DCP, which is extremely advantageous in the shallower, less consolidated soils. MASW shear wave velocity results showed similar trends to the DCP cone tip resistance and allowed for measurement of stiffer soils where the DCP reached refusal. In addition, the results from the DCP, GPR and vibracores compared well. Thus, the use of the DCP and GPR systems as minimally intrusive testing options in fragile dune systems was verified.

El equipo de Penetrómetro dinámico ligero a energía variable (PANDA) se ha destinado principalmente alcontrol de calidad de compactación, dejando de lado su uso para la clasificación o identificación del tipo de material, talcomo se ha hecho con resultados del ensaye de CPTu. Con un sondeo de PANDA se aprovecha la versatilidad de ser unequipo compacto y con posibilidad de acceder a zonas donde es complicado ingresar con equipos convencionales para laejecución de SPT y CPTu, con la finalidad de caracterizar los materiales en áreas específicas, de difícil acceso o donde nose requiere llegar a una profundidad mayor a los 5 m. En el presente artículo se propone el desarrollo de una correlaciónpara identificar el tipo de material a partir de la resistencia dinámica de punta (qd) de sondeos de PANDA, llevados a caboen un depósito con descarga de jales fluidos (slurry), partiendo de una calibración con resultados de pruebas de laboratorioen muestras de jales gruesos y jales finos (lamas) extraídas en el mismo punto de ejecución de los sondeos de PANDA,con el propósito de contar con una expresión con mayor aplicabilidad en los jales, que permita una rápida caracterizaciónen zonas superficiales o de difícil acceso dentro del depósito.

The progressive degradation of railway ballast over time increases the degree of ballast fouling and poses significant drainabilityconcerns leading to frequent maintenance activities. To avoid such issues, an effective and continuous characterization ofthe physical properties of the ballast layer is deemed necessary. This paper introduces the combined use of a bender element(BE) piezoelectric field sensor and a PANDA dynamic cone penetrometer for periodic evaluations of ballast condition overthe traffic use. To simulate various levels of ballast degradation, box tests were conducted using a dolomitic ballast materialcompacted in a laboratory-sized testbed with fouling indices ranging from zero to 39%. BE sensor pairs were embedded inthe ballast layer to calculate the small strain modulus behavior of the ballast assessed through shear wave velocity measurementsunder different confinement conditions. Strength profiles of the ballast at different fouling levels were also measuredusing the PANDA penetrometer. Experimental findings from both test methods indicate the existence of a dense state ofballast linked to a certain fouling index that maximized stiffness and strength characteristics of the tested ballast in dry condition.Accordingly, the potential use of BE field sensors embedded within in-service ballasted track coupled with periodicpenetration testing can be a viable approach to evaluate ballast layer degradation. Various void packing conditions associatedwith ballast fouling levels can be linked to important ballast layer modulus and strength behavior. Further, such smart sensingof ballasted track behavior can provide long-term performance monitoring solutions for ballast cleaning and maintenancescheduling.

Le phénomène de liquéfaction concerne certaines formations géologiques définies par leur nature (sables, limons,vases), granulométrie (uniforme, de 0,05 à 2 mm) ; cohésion (plasticité faible), densité (lâche et moyenne) et degré desaturation (saturée). Généralement ce phénomène a lieu dans des sols sableux non cohésifs et saturés ; mais aussi dansdes sables moyennement grossiers, des limons alluvionnaires, des cendres, des résidus miniers… qui peuvent formerdes dépôts peu denses et instables, particulièrement si ceux-ci présentent une granulométrie uniforme et des particulesde forme arrondies. La liquéfaction se produit principalement dans les sols proches de la surface (z < 15m) et rarementdans des couches plus profondes. La plupart des cas recensés dans la littérature concernent les 10 premiers mètres deprofondeur.

During the Petrinja earthquake sequence in December 2020, numerous liquefied sandejections came to the surface along the Kupa, Sava and Glina rivers in Quaternary alluvialsediments. In October 2022, we performed field investigation in the epicentral area, involvinggeotechnical and geophysical techniques, at different sites with sand ejecta or lateralspreading along the Kupa river. Geotechnical soundings were carried out with variable energydynamic cone penetrometer. We used both Light Dynamic Penetrometer (DPL - Panda)and its Super Heavy version (DPSH - Grizzly), to evaluate the soil characteristics and tospecify the geometries of the various subsurface sedimentary layers. This paper presentsone of the ground site models based on DPL and DPSH tests along with Electrical ResistivityTomography (ERT) profiles. The resulting models will contribute to a better understanding ofmechanical characteristics of soils and their potential to liquefy

In an attempt to go beyond the conventional laboratory experiments widely reported in literature around the emerging technique ofsoil bio-cementation, this work addresses key challenges related to its large-scale application. Precisely, a state-of-the-art installation witha draining bottom boundary is introduced and a novel treatment strategy, based on ex-situ hydrolysis within a 1000 L bioreactor, isdescribed. Hydrolyzed solutions are injected in a tank filled with 0–4 mm sand, via a system of eight injection tubes to treat a total surfaceof 40 m2 across a depth of 2 m. A multilevel, spatial and temporal quality control system is used to monitor the injection processes acrossseveral cycles via chemical and hydraulic means. In total, 20.8 m3 of reactant solutions are supplied to the targeted zone, equal to onepore volume and over 120 chemical analyses are carried-out. Reaction efficiencies overall exceeded 80%, while by increasing the numberof treatment cycles, and thus calcification levels, a gradual increase in the recorded pressure at the injection inlet was captured, thatreached up to 75 kPa. Zones where the injection pressure increased the most are found to yield better resistance in the vicinity of thecorresponding injection tube. A dynamic penetrometer campaign reveals that increase in the tip resistance, is found to exceed 5 MPaand yields more homogenous response across the bottom 0.5 m of the tank, which is believed to reflect the effect of initial confinementon the deposition of calcite. For the zones with the highest cementation, correlated u’ values yield a 5
increase, while the oedometricmodulus is found to double. The results suggest that ex-situ bio-cementation, where hydrolysis occurs in bioreactors instead of inside thesoil mass, is capable of yielding similar precipitation efficiencies and mechanical improvement compared to traditional bio-cementation,where bacteria are injected directly into the soil. Finally, the monitoring of MICP at the scale of typical geotechnical works is discussedalong with the problematic of residual ammonium, which in this study is found to reach absorded quantities of 4 mol/L.

Among the geotechnical in situ tests, the dynamic penetration test (DPT) is commonly used around theworld. However, DPT remains a rough technique and provides only one failure parameter: blow count orcone resistance. This paper presents an improvement of the dynamic cone penetration test (DCPT) forsoil characterisation based on the wave equation theory. Implemented on an instrumented lightweightdynamic penetrometer driving with variable energy, the main process of the test involves the separationand reconstruction of the waves propagating in the rods after each blow and provides a dynamic coneload-penetration (DCLT) curve. An analytical methodology is used to analyse this curve and to estimateadditional strength and deformation parameters of the soil: dynamic and pseudo-static cone resistances,deformation modulus and wave velocity. Tests carried out in the laboratory on different specimens(wood, concrete, sand and clay) in an experimental sand pit and in the field demonstrated that theresulting DCLT curve is reproducible, sensitive and reliable to the test conditions (rod length, drivingenergy, etc.) as well as to the soil properties (nature, density, etc.). Obtained results also showed that themethod based on shock polar analysis makes it possible to evaluate mechanical impedance and wavevelocity of soils, as demonstrated by the comparisons with cone penetration test (CPT) and shear wavevelocity measurements made in the field. This technique improves the method and interpretation of DPTand provides reliable data for shallow foundation design.

Fouling and deterioration of the ballast are a major problem in opera-tion of railway tracks. Its characterization is thus a fundamental task to optimize decision-making in maintenance or renewal programs. This study aims to char-acterize the fouled ballast using a dynamic penetrometer (PA.N.D.A) and geoen-doscope test1. The methodology presented consists in analyzing the resistance properties of each layer by means of dynamic cone resistance (qd) and then per-forming a geoendoscope test to obtain borehole images for a material character-ization. Statistical analysis of cone resistance and statistical image parameters (texture and colometry) shows their dependence on the degree of fouling as well as on its nature. As ballast fouling increases, the average cone resistance initially increases and then decreases. Images features also depend on the proportion of fouling but especially allow to distinguish different contents of fine pArticles in the fouling material. However, each of the measurements taken separately is not sufficient to determine a ballast fouling amount. In this way, a last study on data fusion has been carried out and shows an improvement in the quantification of the Fouling Index.

En raison de la difficulté de prélèvement d'échantillons non remaniés de sable, la possibilité d'évaluer directement sur site, à partir d'essais in situ, des paramètres de comportement contrainte-déformation pour les sables constitue un enjeu important en géotechnique. Récemment, un nouveau type d'essai au pénétromètre dynamique léger, à énergie variable, associé à une méthode d'analyse dynamique spécifique, a été développé. Le dispositif est entièrement instrumenté et le principe de base est d'analyser le phénomène de propagation d'ondes dans les tiges au cours de l'impact en vue d'obtenir, pour chaque impact, la courbe de chargement force-déplacement de la pointe et d'en tirer des paramètres élémentaires du sol. Dans ce contexte, un programme expérimental a été réalisé à l'aide de ce dispositif évalué en chambre d'étalonnage sur un sable de référence, le sable de Fontainebleau NE34. On a, en particulier, étudié l'influence de paramètres tels que l'état de densité du sable, l'état de contraintes appliqué au massif et l'état du sable (sec ou saturé) sur les résultats obtenus à l'aide de ce dispositif. Sur la base de l'analyse de ces résultats, on donne quelques pistes de réflexion concernant l'utilisation de ce dispositif pour l'évaluation du risque de liquéfaction des sables.

Leaching waste deposits are structures used for the storage of residues generated by hydrometallurgical processes forobtaining copper. Although the mechanical behavior of these types of deposits have historically remained adequate in seismicallyactive countries like Chile, it is necessary to evaluate – for closure and post-closure stages – long-term physical stability, potentialfailure mechanisms, slope stability, and seismically induced deformations. However, the physical and chemical characteristics ofsuch materials impedes geomechanical characterization via traditional in-situ and laboratory tests. Thus, this Article presents a costefficientmethodology to be implemented in evaluating long-term physical stability of leaching waste deposits. We identify the maincontributing failure mechanisms, estimate in-situ conditions, and present the geomechanical parameters for stored material mostsuitable for analysis.

Na geotecnia, as investigações de campo é uma etapa indispensável para o planejamento urbano, para avaliação e elaboração de projetos e, consequentemente, para execução das obras de Engenharia. Sempre buscando, quando possível, técnicas simples, com baixo custo, para a elaboração de bancos de dados, que são compostos por investigação para elaboração de cartas geotécnicas. As cartas geotécnicas destinadas ao planejamento auxiliam na iniciativa de políticas públicas de harmonização entre o processo de urbanização e meio ambiente.As tecnologias de processamento computacional de dados cartográficos tornaram possível manipular, gerenciar e finalmente analisar uma grande quantidade de dados referenciados espacialmente. O Ensaio de Simples Reconhecimento, ou Standard Penetration Test (SPT), é um ensaio muito utilizado no Brasil e no mundo pela simplicidade, robustez, baixo custo e alta experiência empírica acumulada. O ensaio realizado com o equipamento denominado penetrômetro dinâmico leve de energia variável (PANDA 2) fornece dados importantes do perfil geotécnico, por intermédio de aquisição automática em tempo real de uma forma simples e rápida.Foi proposto neste trabalho uma correlação entre os ensaios SPT e PANDA 2, sendo selecionada uma área que está inserida em uma região do Distrito Federal que está passando por um processo de planejamento de urbanização. A área selecionada para o estudo está localizada no Setor Habitacional Taquari Etapa II, inserida na Região Administrativa do Lago Norte.Nesta pesquisa foi proposto também um método de interpolação em ambiente SIG dos dados do PANDA 2 para diferentes profundidades até 4,5m e a partir da correlação dos dados de resistência a penetração SPT com o PANDA, foi realizada uma estimativa da distribuição espacial do valor do SPT para diferentes profundidades até 4,5m, a fim de colaborar com o processo de desenvolvimento urbano da região e fornecer dados para futuras pesquisas que sejam realizadas no setor.

En este trabajo se presenta la aplicación de modelosgeoestadísticos a 71 ensayos con penetrómetro dinámicopesado DPSH Grizzly® realizados durante los últimos7 años en una amplia zona del sector norte de la ciudadde Punta Arenas. Este sector, se caracteriza por tener unaextensa unidad, compuesta de arenas saturadas sueltaspotencialmente licuables, la que está acompañada deotras unidades de menor extensión compuesta por suelosorgánicos y arcillas blandas denominada localmente como“mazacote”. Los modelos geoestadísticos permitieronobtener una correlación espacial de los datos de resistenciapor punta del penetrómetro dinámico DPSH Grizzly®.Mediante estimaciones de interpolación geoestadísticoKriging, se identificaron las unidades geotécnicas queconforman el sector en estudio y también las zonas mássusceptibles al fenómeno de licuación. Se complementóel estudio con datos de sondajes SPT, cartas geológicas ygeomorfológicas y calibraciones al penetrómetro dinámicoDPSH Grizzly®, realizadas durante la ejecución y revisiónde los ensayos.

On a réalisé des essais pénétrométriques de chargement en pointe(dynamiques DCLT et statiques CLT) avec des sables de référence. En exploitant lescourbes DCLT, on estime les courbes CLT. Celles-ci présentent une bonne correspondanceavec les courbes expérimentales. Cette analyse permet de dissocier l’effet statique de l’effetdynamique et ouvre la voie à une meilleure interprétation de l’essai DCLT.

Lateritic soils are the most common materials in tropical areas and widely used in pavement engineering. Infact, in these areas, pavement compaction control is generally performed through the measurements of thein-situ unit weight of the soils. However, these methods are time-consuming and expensive. So, in manycountries, methodology based on the use of the dynamic penetrometer has become widespread for rapid andless costly control of pavement quality. This methodology is efficient but requires calibration between thecone resistance and the dry unit weight. Due to the specific nature of lateritic soils, to their assumed widevariability and probably to other reasons, no calibration has actually been performed in-situ for these soils. Thecalibrations performed until now, has been carried out using chambers in the laboratory. This process providessome bias for the prediction of in-situ dry unit weight, due to the chamber boundary effects which affect coneresistance. This paper proposes a methodology that consists of testing the soils in-situ and in the laboratory,studying cone resistance according to compaction parameters in order to estimate the boundary effects andto propose a model to take them into account when predicting in-situ dry unit weight.

This work presents the results of tests carried out as part of the study of the influence of ballast fouling materials and compaction states on the dynamic cone resistance. It is a complement for a previous study on the statistical analysis of the influence of ballast fouling on penetrometer and geoendoscope data [1].As a result of this previous work, a particular behaviour of the average cone resistance was highlighted. The cone resistance (qd) initially increases with Fouling Index, highlighting the mechanical resistance to penetration improvement of the ballasted layer. Then, when the ballast is fouled, this mechanical resistance decreases. However, the tests cases This behaviour was highlighted for specimens without compaction differences.The present study exposes results obtained from similar test specimens compacted in two new distinct sates. For the same range of Fouling Index (FI), this study confirms the previously highlighted behavior for more compacted test cases with only sandy fouling material.

La caractérisation de sols est une condition indispensable pour le dimensionnement des fondations.Au niveau mondial, les travaux de caractérisation, dont l’objectif est de fournir les paramètres du solpermettant d’adapter l’ouvrage au terrain, sont souvent basés sur la réalisation d’essais in situ.Toutefois, la plupart des essais géotechniques in situ ne permettent pas d’identifier directement lesparamètres constitutifs des couches de sol. De plus, la plupart de ces méthodes ne permettent pasd’avoir une caractérisation des sols de surface avec grande résolution et à faible coût.L’essai de chargement dynamique en pointe (DCLT) réalisé au pénétromètre léger instrumentéPANDA 3® permet d’obtenir des signaux de force, de vitesse et de déplacement au niveau de lapointe au cours de la pénétration. L’essai DCLT permet ainsi d’obtenir une courbe de chargementdynamique du sol lors de la pénétration : la courbe DCLT. Le caractère dynamique et transitoire decette technique, rend possible l’application des méthodes d’analyse intégrant différentes approches(e.g. essais de choc, modèles analytiques d’interaction sol-pointe).L’essai DCLT étant assimilable à un essai de choc, l’exploitation des signaux de force et de vitesselors des premiers instants suivant l’impact permet ainsi d'étudier le comportement à faiblesdéformations et d’en déduire une mesure de vitesse d’ondes du sol. Par ailleurs, du fait de lasollicitation, de la géométrie et des conditions aux limites, l’essai est similaire également à l’essai dechargement dynamique de pieu, où la réponse du sol en pointe est exprimée à l’aide d’un modèled’interaction. Actuellement, un modèle d’interaction de type masse-ressort-amortisseur est le plussouvent appliqué pour exploiter ce type d’essai. Toutefois, celui-ci ne permet pas de traduirecorrectement le phénomène, ni d’accéder à des paramètres d’usage courant en géotechnique (e.g.paramètres effort-déformation). C’est pourquoi, il s’avère nécessaire appliquer une méthodologied’interprétation basée sur un modèle d’interaction plus réaliste et alimenté par les paramètrescaractérisant le comportement du sol déterminé lors de l’essai. Cela constitue le principal objectif dece travail de Thèse Phd.Pour ce faire, une étude expérimentale en laboratoire a été effectuée sur des sables propres deréférence. Ceci afin d’évaluer les différentes méthodes d’interprétation existantes et de testerl’application d’un modèle d’interaction propre à l’essai. Cette étude expérimentale, basée sur laréalisation d’essais de chargement dynamique et statique en chambre d’étalonnage, a permis dedémontrer que les courbes DCLT sont qualitativement comparables aux courbes d’essais statiques.Pour compléter l’étude expérimentale, un modèle numérique en différences finies a été conçu afin desimuler l’essai DCLT. Ce modèle a permis de confirmer les constatations expérimentales etd’investiguer l’influence de différents paramètres. L’analyse des courbes DCLT numériques a permisde vérifier les méthodes d’obtention des paramètres de résistance et de déformation intégrant laméthodologie proposée.Finalement, l’application de la méthodologie d’interprétation des résultats d’essais DCLT est illustréein situ sur un site sableux. Les résultats DCLT obtenus sont comparés à ceux issus des différentesméthodes d’investigation.

La liquéfaction est un phénomène qui peut engendrer des dommages importants pour les êtres humains et leurs activités, et l'évaluation de ce phénomène nécessite donc une attention particulière .Actuellement, l'évaluation du potentiel de liquéfaction peut être réalisée à partir d’essais en laboratoire ou in situ, mais chaque équipement et méthodologie présente des avantages et des inconvénients qui peuvent limiter leur utilisation. Sur cette base, le développement de nouvelles méthodes d'évaluation du potentiel de liquéfaction est nécessaire. Dans ce contexte, une méthode d'évaluation du potentiel de liquéfaction, basée sur la réalisation d'essais de pénétration dynamique à énergie variable, à l'aide d'un pénétromètre dynamique instrumenté d'accéléromètres et de capteurs de déformation permettant la mesure de signaux dynamiques pour chaque impact de marteau, a été proposée. Pour le développement de la méthode proposée, des essais de pénétration dynamique ont été réalisés sur des massifs de sables d’Hostun (HN31) et de Fontainebleau (NE34) dans une chambre d'étalonnage K0. Des essais triaxiaux cycliques pour évaluer les propriétés de liquéfaction des deux sables ont également été réalisés. Avec l’ensemble des résultats obtenus, on peut conclure que la méthode proposée permet d'évaluer les propriétés de liquéfaction des sables.

La Grande Guerre a fortement marqué les paysages, notamment sur le front ouest, des Flandres àl’Alsace. Les cratères de mines, les trous d’obus, les abris, les tranchées et boyaux decommunications dégagent des « polémopaysages » caractéristiques de la zone de front. Ces« polémoformes » subsistent sous couvert forestier et sont mises en évidence à l’aide du LiDARaéroporté alors qu’elles sont intégralement nivelées en zone cultivée. En Champagne, l’extensionde la ville de Reims occasionne des prescriptions archéologiques et permet de mieux connaîtrel’organisation spatiale et la nature du remplissage de ces formes, par une approchearchéométrique (pénétromètrie dynamique, coupes mécaniques orientées, photographies pardrone). L’analyse réalisée sur un secteur expérimental de 2 ha, en première ligne de défense,permet de caractériser les structures archéologiques de la Grande Guerre dans un contextetypique de rendosols sur poches de cryoturbation étirées dans la craie de Champagne. Lesrésultats montrent que les formes de la Grande Guerre sont nivelées par un remplissagepolyphasé avec une sédimentation fine synchrone au conflit, suivie d’un remblaiementhétérométrique peu consolidé. Ce dernier provenant des géomatériaux du parados et du parapetdémantelés, est riche en fragments métalliques des réseaux de défense accessoire, surmonté d’unapport de terre végétale. La bombturbation détermine également une contamination métalliquepar « effet pépite » circonscrite aux entonnoirs d’obus, comblés par des apports de terre. Cespédoturbations anthropiques déterminent d’importantes disparités spatiales des réserveshydriques du sol et sont associées à des risques géotechniques et pyrotechniques.

Pavement design with some soils, such as lateritic soils, is still a “real challenge” in some countries. In the tropical countries guide, recommended for Burkina Faso, the pavement design is performed according to the class of traffic and the soil bearing capacity, characterized by the soaked CBR index (Californian Bearing Ratio). In practice, the validation of pavement structures is possible using numerical models requiring the thickness, the Poisson’s ratio and the elastic modulus of the pavement’s layer materials, as input data for the stresses and the strain calculation. Until now, the guides provide none value of the modulus for the lateritic soils. So, the modulus is estimated by assimilating the lateritic soils to untreated coarse gravels (or GNT: Graves Non Traitées in the French guideline) with known modulus or by using empirical correlations based on the soaked CBR index. This approach lead to an erroneous estimating of modulus of lateritic soils, and to an under or overdesign of pavement structures, due to the fact that the specific correlation suitable for these soils in Burkina Faso is not known. So, this paper was interested in the characterization of lateritic soils from Burkina Faso, according to their CBR bearing capacity, their elastic modulus and to their compaction parameters, after having been assured that the selected soils were representative of country’s road soils. The objective is to perform a specific model for estimating the elastic modulus of these soils. Analysis of the studied parameters showed that CBR and elastic modulus, both depend on moisture content and dry unit weight of soils. A correlation was thus performed between elastic modulus and CBR index. The specific correlation obtained is in power form: E= a.CBRb and relatively close to whose obtained by Green and Hall, where a=66.50 and b=0.526.

Soil liquefaction is one of the most destructive problems produced during earthquakes and its analysispresents difficulties associated with taking samples and performing tests under the surface. Against this, in situ analysismethod based on penetration tests (CPT, SPT) have been developed. Each penetration equipment has its own characteristicsand different application possibilities, so it is necessary to expand the analysis methods to other equipment. Thispaper presents a state of the art on the application of the PANDA® variable energy light dynamic penetrometer in theanalysis of resistance to liquefaction. An exhaustive bibliographic review of the PANDA® penetrometer developed methodshas been carried out. It is concluded that the methods presented are applicable for the preliminary analysis of liquefactionresistance.

When exploration depth is shallow or site access is limited, a dynamic lightweight penetrometer is an attractive alternative to largepenetrometers. Cone resistance, regardless of the penetration test, is influenced strongly by soil conditions: dry unit weight, overburden stressand water content of the surrounding soil, and fines content. This study explored the effects of these parameters on the cone resistance is in acalibration chamber. A series of tests was conducted in clean sands and mine tailings materials, subjected to different overburden stresses andprepared to different void ratios and degrees of saturation. It was found that dry unit weight and overburden stress significantly increases coneresistance. The effects of water content on cone resistance were more significant in mine tailings materials than in clean sands. An overburdencorrection factor for a dynamic lightweight penetrometer is proposed based on soil conditions, including fines content. Differences fromcommon correction factors used for large penetrometers were observed, and were attributed to the type of soil and range of overburden stressexplored in this study.

Alternative compliance testing methods for earthworks have been covered in many recent publications. One key aspectof alternative compliance testing is that it supplies parameters that correlate directly to design, rather than index tests which have anadditional level of correlation and error margin. For example, laboratory CBR testing is a time-consuming test with a significantcorrelation error with design parameters, particularly in cohesive materials in a semi-arid environment. Performance-based formationdesign is a requirement for many Australian projects, including the Inland Rail (IR) project and finds many applications withinoperation and maintenance. Rail formation performance-based mechanistic design allows a balance between capital expenditure(CapEx) and asset operation/maintenance (Opex) by providing an indication of the formation performance with rail traffic forecast.This performance is expressed in terms of deformation governed by strength and stiffness. Resilient modulus and compressivestrength are critical soil input parameters for mechanistic design and the estimation of deformation over time. These parameters canbe tested directly using alternative compliance testing methods. This paper presents the results of compressive strength and resilientmodulus measured in situ using a Variable Energy Dynamic Penetrometer (VEDP), Light Weight Deflectometer - Portable Impulse(LWD-PI), and Plate Load Test (PLT) and laboratory Unconfined Compressive Strength (UCS) during a full-scale trial. This paperalso presents an alternative compliance testing method for a brownfield application. A geospatial/cloud based report displaying nearreal-time communication of the alternative compliance results is presented. The alternative tests reduce the level of laboratory testingeffort while the near real time display of results aids in construction time frames which is of particular benefit to projects in remotelocations. The methods can be combined with traditional field testing methods to develop site-specific correlations and validategeotechnical parameters assumed in the design.

Soil liquefaction is one of the most destructive phenomena caused by earthquakes. Nowadays, it has beenmainly studied regarding the risk assessment trough in-situ penetration tests (SPT, CPT) that allow identification of potentiallyliquefiable layers. However, most of these techniques are limited by site accessibility, cost and amount of informationcollected during the survey. Development of portable, cost effective and efficient equipment as well as the methodsto assess cyclic resistance ratio (CRR) are necessary. This paper presents the first results aimed at establishing apseudo-empirical laboratory methodology for liquefaction risk assessment of sandy soils through a lightweight instrumenteddynamic penetrometer. A series of dynamic test on sand samples were performed in calibration chamber. Fillingmaterial of each sample is sand of Fontainebleau, different density and overburden pressure has been reproduced. Oneach sample, a dynamic penetration test was conducted and for each hammer blow, strain, forces, acceleration and displacementwere recorded as well as dynamic penetration resistance (qd), computed by wave equation analysis, are obtained.At the end, graphs or charts for correlating qd, density index and overburden pressure are presented in order toassess CRR of soil.

Le Transgabonais, principale ligne ferroviaire du Gabon, constitue un maillon essentiel dans l’´economie de cepays. En effet, cette ligne est utilis´ee pour le transport des biens et des personnes mais ´egalement et principalementpour l’acheminement des minerais (notamment du mangan`ese), l’une des principales ressources du pays. Une partiede cette ligne est construite sur des sols p´elitiques au comportement m´ecanique m´econnu. Dans cette partie dela voie, des probl`emes de d´eformabilit´e importants, pr´esents sur des portions r´epertori´ees comme  zones instables et ayant entrain´es plusieurs accidents, obligent actuellement l’entreprise exploitante `a multiplier les op´erationsde maintenance et `a r´eduire le nombre et la vitesse des convois entrainant de fait, un ralentissement de la chaine deproduction des minerais.L’objectif de ce travail est double. Premi`erement, il s’agit d’´etudier le comportement de ces sols fins, constitutifsde la plateforme, en conditions non satur´ees et sous sollicitations cycliques. Par ailleurs, il s’agit de proposerune m´ethodologie de caract´erisation et de diagnostic de la voie in-situ permettant d’alimenter un mod`ele depr´ediction de d´eformations permanentes en vue d’optimiser la politique de maintenance. Pour ce faire, deux zonesinstables particuli`eres ont ´et´e ´etudi´ees. Une campagne d’essais in-situ a ´et´e r´ealis´ee sur chacune de ces zones envue de caract´eriser leurs propri´et´es en place et la variabilit´e de ces propri´et´es. Par la suite, des campagnes d’essaisde laboratoire ont ´et´e effectu´ees avec deux objectifs. D’une part, d´eterminer les courbes calibration des mat´eriauxconstituant la plateforme en vue de relier leur poids volumique sec `a la r´esistance dynamique de pointe. D’autrepart, caract´eriser les propri´et´es de ces mat´eriaux, d´eterminer leurs courbes de r´etention en fonction de leur densit´eet ´etudier leur comportement en condition non satur´ee et sous sollicitations cycliques.Les r´esultats obtenus ont permis premi`erement d’identifier les mat´eriaux constituants la plateforme. Dans undeuxi`eme temps, l’obtention des courbes de r´etention d’eau pour diff´erents indices des vides initiaux, a permisd’´etablir une relation lin´eaire entre l’indice des vides et la succion d’entr´ee d’air. Les essais triaxiaux (monotoneset cycliques) ont permis d’´etudier le comportement du sol et de  caler  un mod`ele de pr´ediction des d´eformationspermanentes. Ce mod`ele donne une bonne estimation de la d´eformation permanente et, est aliment´e `a partir desmesures in-situ. Il peut ˆetre aussi utilis´e pour estimer les tassements du sol de plateforme.

This paper proposes a methodology for the calibration of the curves from the dynamic cone loading test (DCLT) andthe settlement curves of the shallow foundations according to the load-settlement curve method. A procedure for the analysis ofobtained DCLT curves is proposed to separate the dynamic and static components. The fitting of a hyperbolic model andnormalization with respect to cone resistance is carried out. The obtained DCLT curves are compared and adjusted based on differenttests carried out either in the laboratory or in situ. The results show the practical and technical feasibility of the method

Conventional geotechnical soil classifications aim to classify soils into families withgeotechnical characteristics and therefore similar behaviour, however, they require coresamples and laboratory identification testing. Several empirical systems for estimating thenature of the soils have been developed on the basis of several in situ geotechnicaltests. However, at present these systems remain empirical and they are often only used on anindicative basis. The objective of this article is, based on the analysis of dynamic penetrometricsignals, to develop a methodology able to provide an estimate of the nature of the soilcrossed. The methodology developed provide an automatic classification based on ArtificialNeuron Networks (ANN) tools. Two types of ANN architectures were considered: MultilayerFeedforward Perceptron (MFP) and Probabilistic Neural Network (PNN). The learning of thesetwo tools was achieved through a base carried out in the laboratory and in situ. The bothclassification models were then tested in blind conditions and showed a good efficiency forcalibrated soils and promising results for in situ soils.

The PANDA variable energy dynamic cone penetrometer (DCP) is a mobile, instrumentedDCP that enables rapid site investigation by one user. The PANDA was utilized in this study tomeasure cone tip resistance and develop site profiles at a blast liquefaction test site inChristchurch, New Zealand. The blast liquefaction testing occurred at two areas within the site.The first blast test was performed in soil that had been improved by resin-injection, whereas thesecond test was performed in untreated soil. Measurements were performed with the PANDADCP prior to liquefaction and following liquefaction to evaluate changes in soil resistance as aresult of liquefaction. Cone tip resistance profiles were developed for depths to 4.5 m and tookapproximately 30 min to complete. Results of the testing showed changes in cone tip resistanceas a result of liquefaction for the untreated site where a decrease in resistance was observed. Inaddition, the PANDA DCP results were compared with cone penetration tests that wereperformed prior to liquefaction at both test areas and showed good agreement. The PANDA DCPwas found to be a useful tool for site investigation following blast liquefaction tests as tests couldbe completed within 30 min of deployment in difficult to access areas.

Since soils are natural and non-homogeneous materials, spatial variability of their properties hasbeen recognised as one of the main sources of uncertainties affecting geotechnical analyses.However, soil testing is limited and the description and quantification of the resulting soilvariability still remain largely subjective in practice. In this paper, anapproach is proposed torationally evaluate the soil spatial variability using field data provided by a site investigationprogramme based on a lightweight dynamic cone penetrometer test. The first part deals withthe boundary identification of statistically mechanical homogeneous soil units. The second partfocuses on modelling spatial variability through 3D conditional random fields in thehomogeneous soil units previously identified. This approach has been applied to and studied ina real site investigation carried out in an alluvial Mediterranean deltaic environment.

Este estudo tem como objetivo apresentar o ensaio PANDA 2 como uma nova possibilidade deensaio de campo para solos tropicais e introduzir um novo conceito na análise usando o Princípio daConservação da Energia Mecânica para desenvolver a energia de cravação. O número de golpes em cadasondagem é também apresentado como uma maneira de comparar a produtividade do ensaio com diferentesseções transversais. Os resultados mostraram que o ensaio desenvolvido com seções transversais de 4 cm² sãomais produtivos e a análise usando conceitos de energia possui uma maior força representativa do ponto devista físico.

Investigar as propriedades mecânicas do solo é imprescindível para que se tenha um bom resultadono cálculo de projeto nas obras de engenharia. É necessário compreender as diferentes condições de campoem que o solo se encontra e como estas influenciam em seu comportamento, uma vez que o solo é um materialheterogêneo e, muitas vezes, não saturado. Neste contexto, insere-se a sondagem PANDA 2, muito conhecidapela sua praticidade, leveza e rapidez na execução de sondagens rasas do subsolo. Assim, este estudo visa, pormeio da sondagem PANDA 2, analisar a influência das distintas condições de campo, nos períodos seco echuvoso, nos parâmetros de resistência à penetração do solo de um campo experimental da Escola deEngenharia Civil e Ambiental (EECA) da Universidade Federal de Goiás (UFG). Foram executadas seissondagens, sendo três no período seco e três no período chuvoso, ao longo de cinco metros de profundidade.Os resultados indicaram que os primeiros 0,75 m apresentam os maiores valores de resistência à penetração(qd). Verificou-se que o PANDA 2 apresentou considerável sensibilidade na aquisição dos dados em funçãoda condição de campo, e que o acréscimo de coesão devido à variação da sucção matricial do solo tem grandeinfluência no parâmetro qd ao longo da zona ativa do solo.

No intuito de subsidiar um reconhecimento local, buscar técnicas, equipamentos versáteis combaixo custo e ferramentas digitais adequadas para elaboração de um produto que subsidia a cartografia geotécnica, esta pesquisa propõe a utilização do Ensaio de Penetração Dinâmica de Cone Leve tipo PANDA2, equipamento portátil, com um dispositivo de aquisição automática de energia e de profundidade de cravação, fornecendo um atributo significativo de resistência mecânica dos materiais inconsolidados, utilizado conjuntamente com o Sistema de Informações Geográficas (SIG) que permite manipular, gerenciar e analisar dados coletados referenciados espacialmente. Isto posto, foi possível elaborar uma Carta de Resistência àPenetração que servirá como contribuição paras cartas geotécnicas que atendam à demanda da região do Setor Habitacional Taquari Etapa II, localizada em Brasília-DF, por estudos aplicados ao planejamento urbano, visto as discussões acerca da sensibilidade ambiental da área estudada.

Пути сообщения в России по праву занимают одно из ключевых мест в народном хозяйстве в связи с географическим условиями, технологическими особенностями экономики и возможностью максимального использования транзитного потенциала страны. Проблема модернизации транспортной системы России, ее адаптации к требованиям функционирования народного хозяйства и внешнеэкономических связей становится все более актуальной для регионов Севера.В рамках основного этапа экспедиции «Трансполярная магистраль», проведенной Русским географическим обществом (РГО) совместно с Российским университетом транспорта (РУТ) с 19 сентября 2019 года по 15 октября 2019 года специалистами Российского университета транспорта обследованы территории Красноярского края для оценки возможности проектирования и строительства путей сообщения в данных регионах.Отсутствие транспортной инфраструктуры, непредсказуемость поведения мерзлых грунтов при промерзании-оттаивании, наличие слабых грунтов в основаниях сооружений, сложные природно-климатические условия, все эти факторы обуславливают сложность строительства в данных регионах.В данной статье рассмотрено определение прочностных характеристик грунтов с помощью динамического пенетрометра-плотометра Panda в полевых условиях. Сделаны выводы о целесообразности использование данных грунтов в основаниях сооружениях.В связи с отсутствием в Норильском районе карьеров по добыче гранитного щебня и сложность транспортировки данного материала, проанализировано применение отходов Норильской металлургии в качестве замены щебня.Результаты, изложенные в статье, являются частью диссертационного исследования Артюшенко И.А. «Усиление основания земляного полотна вертикальными столбами из щебня на участках с многолетнемерзлыми грунтами».

This paper will present a field comparative study between shear wave velocity measurements (Vs), deduced from compression wave velocity (Vp) and signal analysis with Panda 3® test, and those obtained by correlation through Ménard pressuremeter tests, CPT tests and seismic surface wave method (MASW) on a sandy site in southern of France. The purpose of this paper is to confirm the consistency of Panda 3® shear wave measurements with measures resulting from traditional geotechnical investigation methods.

On simule le battage d’un pénétromètre dans un sol homogène avec la méthode aux différences finies. L’objectif est de mettre au point un modèle simple mais qualitativement représentatif de cet l’essai Panda 3®. On analyse l’influence des paramètres effort-déformation du modèle rhéologique choisi dans les courbes charge-enfoncement de la réponse du modèle.

Field determination of small-strain modulus (E0) and compressional wave velocity (cp) is a major issue.Even though many techniques allow determining these parameters, most of them are not able to provide precise andreliable data at low-cost. Moreover, most of these techniques do not allow to assess a soil strength parameter. Panda 3®is a dynamic penetrometer for shallow soil characterization. The device’s principle consists to measure wave propagationwithin the rod to each blow during driving. Force and acceleration measurements combined with signal analyses allowthe obtain stress and velocity generate by the impacts. An approach based on the shock theory is proposed to determinecp and E0 from shock related equations. This paper presents the principle and the theoretical background applied. Additionally,shock relationships provide an estimating of soil axial stress-strain response during each shock. The results froma series of test carried out in calibration chamber on two sands at different densities, moisture contents and confiningstresses are presented. These results are compared to those reported in the literature.

Dynamic penetrometer is a worldwide practice in geotechnical exploration and Panda lightweight variable energy is the most developed device nowadays. Widely used in France, in Europe and other countries, Panda remains unknown. This paper presents the Panda test and the main goal is to establish an empirical correlation between dynamic variable energy penetrometer (Panda) and cone penetration test CPT. This study is based on about 100 comparative tests performed the last 20 years around the world. In order to demonstrate the good agreement obtained as well as to complete comparative database, an experimental campaign, carried out recently in France, is presented. A general correlation and qc model prediction is proposed.

L'évaluation du risque de liquéfaction d’un site ou d’un ouvrage est nécessaire pour éviter des dégâts humains et économiques. Les méthodes actuelles d'évaluation sont principalement basées sur l'essai de pénétration, SPT ou CPT. Ces méthodes permettent de caractériser le sol et estimer un facteur de sécurité contre l'occurrence ou la non-occurrence d'une liquéfaction. Cet article présente les premiers résultats des essais de pénétration dynamique complètement instrumentés (le P.A.N.D.A.3®) sur des échantillons de sable fabriqués dans une chambre d’étalonnage (état K0). Les résultats montrent une bonne corrélation entre la résistance à la pénétration dynamique qd et l'indice de densité du sol Id, permettant d'établir une équation générale qui relie ces paramètres et la contrainte de surcharge effective appliquée à l'échantillon.

Avec un pénétromètre, la résistance à la pénétration dans le sol peut être mesurée demanière simple. Cela permet de localiser et d'évaluer indirectement la compaction du sol. Enfonction du mécanisme de pénétration, on distingue les types de dispositifs statiques etdynamiques. Outre le mécanisme de pénétration, les types de dispositifs diffèrent aussisouvent en termes d'embouts coniques. La résistance à la pénétration mesurée dépend dedifférents facteurs d'influence, tels que le type d'appareil, la densité du support ou la teneuren eau du sol. Il est donc difficile de comparer les mesures entre différents types depénétromètres, entre des enquêtes répétées ou entre différents lieux.L'objectif du présent travail était de comparer les mesures de différents types depénétromètres et de trouver les causes des éventuelles différences de mesure. Le projetvisait également à faire des suggestions pour des travaux ultérieurs. Afin de pouvoiratteindre les objectifs définis du projet, des tests comparatifs ont été réalisés en été 2019 encollaboration avec l'Office national de surveillance des sols (NABO). À cette fin, des mesuresont été effectuées simultanément sur un total de 12 sites en utilisant à la fois la sondedynamique PANDA et le pénétromètre statique de Eijkelkamp. Cela a permis de collecterdes données de mesure sur des sites présentant des textures de sol différentes et, grâce àdes enquêtes répétées, également une humidité du sol variable. En outre, les relevéssimultanés avec les deux méthodes permettent une comparaison entre les types depénétromètres.Des mesures simultanées avec différents types de pénétromètres et de cônes de sondageont révélé des déviations systématiques entre les types de processus. Les résistancesabsolues à la pénétration de la sonde PANDA et du pénétrologue ne sont donc pascomparables. En moyenne, des résistances de pénétration plus faibles sont mesurées avecle pénétrologue, en particulier lors de l'utilisation de cônes de sondage plus grands. De plus,les couches potentiellement compactes sont imagées de manière disproportionnée avec lasonde PANDA. En dérivant des équations empiriques simples, on a essayé de calculer lesrésistances à la pénétration en fonction de la densité de la litière et de la teneur en eau.Cependant, les valeurs mesurées modélisées ont généralement montré une concordanceinsuffisante avec les résistances à la pénétration mesurées. Pour améliorer les modèles, desvariables supplémentaires, telles que la texture du sol ou un facteur de géométrie pour lapointe du cône, pourraient devoir être intégrées dans les équations.Sur la base des enquêtes menées sur le terrain, les différences entre les typesd'équipements n'ont pu être expliquées que de manière insuffisante. C'est pourquoi denouvelles approches méthodologiques devraient être envisagées dans des étudesultérieures. Par exemple, les données de terrain pourraient être complétées par dessimulations informatiques. Ces simulations permettent de mieux comprendre l'interactionpointe-sol et les forces et résistances qui agissent sur elle. Une autre approche pourraitconsister à mesurer la résistance à la pénétration sur des sols artificiels ou des matériauxsemblables à des sols où les densités et les teneurs en eau des différentes couches sontconnues et constantes. Cette approche pourrait également fournir des explications sur lesécarts de mesure entre les types de méthodes.

Mit einem Penetrometer kann auf eine einfache Weise der Eindringwiderstand im Boden gemessen werden. Dadurch können indirekt Bodenverdichtungen lokalisiert und beurteilt werden. Je nach Eindringmechanismus wird zwischen statischen und dynamischen Gerätearten differenziert. Zusätzlich zum Eindringmechanismus unterscheiden sich die Gerätearten auch oft in Bezug auf die Konusspitzen. Der gemessene Eindringwiderstand ist von verschiedenen Einflussfaktoren, wie der Geräteart, der Lagerungsdichte oder dem Bodenwassergehalt, abhängig. Der Vergleich von Messungen zwischen verschiedenen Penetrometertypen, wiederholten Erhebungen oder unterschiedlichen Standorten wird dadurch erschwert.Das Ziel der vorliegenden Arbeit war es, Messungen verschiedener Penetrometertypen miteinander zu vergleichen und Ursachen für allfällige Messunterschiede zu finden. Das Projekt sollte zudem Vorschläge für weiterführende Arbeiten machen. Um die definierten Projektziele erreichen zu können, fanden im Sommer 2019 in Zusammenarbeit mit der Nationalen Bodenbeobachtung (NABO) Vergleichsprüfungen statt. Zu diesem Zweck wurden auf insgesamt 12 Standorten zeitgleich sowohl mit der dynamischen PANDA-Sonde als auch mit dem statischen Penetrologger von Eijkelkamp Messungen durchgeführt. Dadurch konnten Messdaten von Standorten mit unterschiedlichen Bodentexturen und, aufgrund wiederholter Erhebungen, auch mit variierenden Bodenfeuchten gesammelt werden. Zudem ermöglichen die zeitgleichen Erhebungen mit den beiden Verfahren ein Vergleich zwischen den Penetrometertypen.Durch die zeitgleiche Messung mit verschiedenen Penetrometertypen und Sondierkonen konnten systematische Abweichungen zwischen den Verfahrensarten aufgezeigt werden. Die absoluten Eindringwiderstände der PANDA-Sonde und des Penetrologgers sind deshalb nicht miteinander vergleichbar. Mit dem Penetrologger werden durchschnittlich tiefere Eindringwiderstände gemessen, insbesondere bei der Verwendung grösserer Sondierkonen. Zudem werden potenziell verdichtete Schichten mit der PANDA-Sonde überproportional hoch abgebildet. Durch die Herleitung einfacher empirischer Gleichungen wurde versucht, Eindringwiderstände anhand der Lagerungsdichte und des Wassergehaltes herzuleiten. Die modellierten Messwerte zeigten jedoch im Allgemeinen eine ungenügende Übereinstimmung mit den gemessenen Eindringwiderständen. Zur Verbesserung der Modelle müssten möglicherweise noch weitere Variablen, wie die Bodentextur oder ein Geometriefaktor für die Konusspitze, in die Gleichungen integriert werden.Anhand der durchgeführten Felduntersuchungen konnten die Unterschiede zwischen den Gerätearten nur unzureichend erklärt werden. Aus diesem Grund sollten bei weiterführenden Studien neue Methodenansätze berücksichtigt werden. So könnten Felddaten mit Computersimulationen ergänzt werden. Durch solche Simulationen kann die Spitze-Boden-Interaktion und die dabei wirkenden Kräfte und Widerstände besser nachvollzogen werden. Ein weiterer Ansatz wäre eventuell auch die Messung des Eindringwiderstandes auf künstlichen Böden oder bodenähnlichen Materialien, bei denen die Dichten und Wassergehalte der einzelnen Schichten bekannt und konstant sind. Auch dieses Vorgehen könnte Erklärungen für die Messabweichungen zwischen den Verfahrensarten liefern.

El empleo de equipos geotécnicos avanzados, ligeros y de fácil manejo es cada vez más demandado porlos profesionales del sector. De igual modo, el control de compactación en las obras de tierras, ya seangrandes cuerpos de terraplenes o rellenos localizados de zanjas, cobra una especial importancia paragarantizar su capacidad de soporte con el tiempo. El equipo Panda es un penetrómetro ligero a energíavariable que permite realizar un adecuado control de compactación y la investigación del terreno con finesgeotécnicos.En el presente artículo se aborda la descripción técnica del equipo y su aplicación por Orbis Terrarum enel control de compactación de las arenas de miga (arcosas terciarias de la cuenca de Madrid) que sonampliamente empleadas en la formación de rellenos por sus características óptimas.Para ello se ha realizado un estudio específico basado en una amplia batería de ensayos de laboratoriosobre las arenas de miga para determinar los parámetros necesarios para su control de compactación enel equipo Panda.

Dynamic penetrometer is a worldwide practice in geotechnicalexploration and Panda® lightweight variable energy is the most developed devicenowaday. Widely used in France, in Europe and many other countries, Panda®remains unknown. A brief state of art is presented. The principle, the use andinterpretation as well different relationship with other methods and geotechnical