Modeling of light dynamic cone penetration test – Panda 3 ® in granular material by using 3D Discrete element method

Tran, Quoc Anh; Chevalier, Bastien; Benz, Miguel; Breul, Pierre; Gourvès, Roland

doi:10.1051/epjconf/201714016003

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…Study on the modeling of a light dynamic cone penetration test-Panda 3(R) in granular materials by using 3D discrete element method was carried out by Tran et al, [48]. Light dynamic penetration test-Panda 3(R) provided dynamic loadpenetration curves for each blow.…”

Section: Dynamic Cone Penetration Test For Pavement Strength Evaluationmentioning

confidence: 99%

Laboratory and Field Evaluation of a-6 Lateritic Soil Treated With Reclaimed Asphalt Pavement and Ordinary Portland Cement

Alhaji¹

2019

GEOMATE

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An A-6 lateritic soil was stabilized with Reclaimed Asphalt Pavement and 2% cement. The lateritic soil was mixed with 0, 20 to 140% RAP and each mixture compacted in the laboratory. The soil mixed with120% RAP gave the highest Maximum Dry Density of 2.252Mg/cm 3 . Laboratory California Bearing Ratio test was conducted on the soil, soil/120% RAP and soil/120% RAP/2% cement. A 15m section of untarred road was identified and demarcated into three sections (A, B and C) of 5.0m each. Materials on section A of the road composed of the lateritic soil/120% RAP/2% cement, section B contains lateritic soil/120% RAP, while section C composed of the lateritic soil only. The sections were compacted using smooth drum vibratory roller. In-situ density test and CBR test using Dynamic Cone Penetration test were carried out on the three sections of the road after 1, 7, 14, 28, 60 and 90days. The laboratory densities of materials used for the three sections are 2.254, 2.252 and 2.154g/cm 3 , while in-situ densities after 60 days were 2.249, 2.225 and 2.142Mg/cm 3 for sections A, B and C respectively. The laboratory CBR values after 60 days were 118, 37 and 22%, while the field CBR values were 44.5, 49.0 and 112% for sections A, B and C respectively. It was concluded that in-situ and laboratory densities and CBR values closely agreed. However, the maximum densities were observed after 60days of field compaction. Also, only 90% of in-situ dry density was achieved immediately after the field compaction.

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Section: Dynamic Cone Penetration Test For Pavement Strength Evaluationmentioning

confidence: 99%

Laboratory and Field Evaluation of a-6 Lateritic Soil Treated With Reclaimed Asphalt Pavement and Ordinary Portland Cement

Alhaji¹

2019

GEOMATE

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“…It has been found that the tip force obtained from impact penetration is smaller than that obtained in constant velocity condition. Later, the simulations of dynamic penetration were extended to 3D (Tran et al, 2017).…”

Section: Dem Simulationsmentioning

confidence: 99%

A micromechanical study of the Standard Penetration Test

Zhang

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This thesis explores the potential of models based on the discrete element method (DEM) to study dynamic probing of granular materials, considering realistic particle-scale properties. The virtual calibration chamber technique, based on the discrete element method, is applied to study the standard penetration test (SPT). A macro-element approach is used to represent a rod driven with an impact like those applied to perform SPT. The rod is driven into a chamber filled with a scaled discrete analogue of a quartz sand. The contact properties of the discrete analogue are calibrated simulating two low-pressure triaxial tests. The rod is driven changing input energy and controlling initial density and confinement stress. Energy-based blowcount normalization is shown to be effective. Results obtained are in good quantitative agreement with well-accepted experimentally-based relations between blowcount, density and overburden. A comprehensive energetic balance of the virtual calibration chamber is conducted. Energy balance is applied separately to the driven rod and the chamber system, giving a detailed account of all the different energy terms. The characterization of the evolution and distribution of each energy component is investigated. It appears that the SPT test input energy is mainly dissipated in friction. The energy-based interpretation of SPT dynamic response proposed by Schnaid et al. (2017) is then validated in comparisons between static and dynamic penetration results. Moreover, microscale investigation provides important information on energy dissipation mechanisms. A well-established DEM crushing contact model and a rough Hertzian contact model are combined to incorporate both effects in a single contact model. The efficient user defined contact model (UDCM) technique is used for the contact model implementation. Parametric studies explore the effect of particle roughness on single particle crushing event. The model is then used to recalibrate the contact properties of the quartz sand, being able to use realistic contact properties and then correctly capture both load-unload behaviour and particle size distribution evolution. The calibration chamber results are exploited to investigate the relation between static and dynamic penetration test. This is done first for unbreakable materials and later for crushable and rough-crushable ones. It is shown that the tip resistance measured under impact dynamic penetration conditions is very close to that under constant velocity conditions, hence supporting recent proposals to relate CPT and SPT results. It is also shown that penetration resistance reduces if particles are allowed to break, particularly when roughness is also considered. Esta tesis explora el potencial de los modelos basados en el método de elementos discretos (DEM) para estudiar el sondeo dinámico de materiales granulares, considerando propiedades realistas a escala de partículas. La técnica de cámara de calibración virtual, basada en el método de elemento discreto, se aplica para estudiar la prueba de penetración estándar (SPT). Se utiliza un enfoque de macroelemento para representar una barra impulsada con un impacto como los aplicados para realizar SPT. La varilla se introduce en una cámara llena de un análogo discreto escalado de arena de cuarzo. Las propiedades de contacto del análogo discreto se calibran simulando dos pruebas triaxiales de baja presión. La varilla se acciona cambiando la energía de entrada y controlando la densidad inicial y el estrés de confinamiento. La normalización del recuento de golpes basado en energía se muestra efectiva. Los resultados obtenidos están en buen acuerdo cuantitativo con relaciones basadas en experimentos bien aceptadas entre recuento de golpes, densidad y sobrecarga. Se realiza un balance energético integral de la cámara de calibración virtual. El balance de energía se aplica por separado a la varilla impulsada y al sistema de cámara, dando una descripción detallada de todos los diferentes términos de energía. Se investiga la caracterización de la evolución y distribución de cada componente energético. Parece que la energía de entrada de prueba SPT se disipa principalmente en fricción. La interpretación basada en la energía de la respuesta dinámica SPT propuesta por Schnaid et al. (2017) luego se valida en comparaciones entre los resultados de penetración estática y dinámica. Además, la investigación en microescala proporciona información importante sobre los mecanismos de disipación de energía. Un modelo de contacto de trituración DEM bien establecido y un modelo de contacto hertziano aproximado se combinan para incorporar ambos efectos en un modelo de contacto único. La técnica eficiente de modelo de contacto definido por el usuario (UDCM) se utiliza para la implementación del modelo de contacto. Los estudios paramétricos exploran el efecto de la rugosidad de las partículas en el evento de trituración de partículas individuales. El modelo se usa para recalibrar las propiedades de contacto de la arena de cuarzo, pudiendo usar propiedades de contacto realistas y luego capturar correctamente el comportamiento de carga y descarga y la evolución de la distribución del tamaño de partícula. Los resultados de la cámara de calibración se explotan para investigar la relación entre la prueba de penetración estática y dinámica. Esto se hace primero para materiales irrompibles y luego para materiales triturables y desmenuzables. Se muestra que la resistencia de la punta medida en condiciones de penetración dinámica de impacto es muy cercana a la de condiciones de velocidad constante, por lo tanto, respalda propuestas recientes para relacionar los resultados de CPT y SPT. También se muestra que la resistencia a la penetración se reduce si se permite que las partículas se rompan, particularmente cuando también se considera la aspereza.

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Numerical verification of the continuous calculation method for tip stress during the driving process of the dynamic penetration test

Tran

Chevalier

Benz-Navarrete³

et al. 2019

Soils and Foundations

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This paper presents a calculation method for obtaining the continuous variation in stress between the tip and the soil during dynamic penetration tests, particularly in the case of using the Panda 3 Ò penetration testing device. The originality of the method is that the tip stress can be computed continuously throughout the driving process. For each impact of the hammer on the penetrometer, data are recorded by sensors located at the top of the apparatus. Then, the stress at the tip and the displacement of the apparatus are calculated with a method based on the propagation of waves in the device. A three-dimensional numerical model of the penetration test, based on the Panda 3 Ò specifications and using the discrete element method (DEM), is proposed in this paper. The purpose of the simulations is to validate the calculation method by comparing the curves of the tip stress versus the penetration distance obtained in two different ways, the first being the distance directly observed at the tip and the second being the distance calculated from the data recorded at the top of the penetrometer, as with the experimental device. The entire apparatus is represented, including the hammer, the rod, and the tip, and is driven into the model soil. The calculation method is applied, and the results are compared to the actual response of the soil to the driving of the penetrometer directly at the tip, which can be obtained with the numerical model. The responses are found to be very similar, confirming the theoretical framework and its underlying assumptions. This method is applied to dynamic penetration tests and provides the opportunity to obtain mechanical parameters other than the tip resistance from the tests.

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Modeling of light dynamic cone penetration test – Panda 3 ® in granular material by using 3D Discrete element method

Cited by 5 publications

References 4 publications

Laboratory and Field Evaluation of a-6 Lateritic Soil Treated With Reclaimed Asphalt Pavement and Ordinary Portland Cement

Laboratory and Field Evaluation of a-6 Lateritic Soil Treated With Reclaimed Asphalt Pavement and Ordinary Portland Cement

A micromechanical study of the Standard Penetration Test

Numerical verification of the continuous calculation method for tip stress during the driving process of the dynamic penetration test

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