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1

Verification of strength resistance of sandy soil using small scale penetrometer tests

Saleem Hiba D., Aldefae Asad H., Humaish Wissam H.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2021

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Vol. 30, No. 2

304--314

EN

This study focuses on utilizing cone penetrometer models to determine strength (resistance) of sandy soil and also assessment how the relative density and the angle of friction effects on the measured cone penetration resistance in sandy soil. Simple empirical equations are used also to determine the cone penetration resistance components such as the sleeve resistance and the tip resistance. Simple comparison is performed between the measured and calculated soil strength and well agreement is noticed between them.

2

Steady state of solid-grain interfaces during simulated CPT

Butlanska J., Arroyo M., Gens A.

Studia Geotechnica et Mechanica

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2013

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Vol. 35, nr 4

13--22

EN

It has recently been shown (Arroyo et al. [1]) that 3D DEM models are able to reproduce with reasonable accuracy the macroscopic response of CPT performed in calibration chambers filled with sand. However, the cost of each simulation is an important factor. Hence, to achieve manageable simulation times the discrete material representing the sand was scaled up to sizes that were more typical of gravel than sand. A side effect of the scaled-up discrete material size employed in the model was an increased fluctuation of the macro-response that can be filtered away to observe a macroscopic steady-state cone resistance. That observation is the starting point of this communication, where a series of simulations in which the size ratio between penetrometer and particles is varied are systematically analyzed. A micromechanical analysis of the penetrometer–particle interaction is performed. These curves reveal that a steady state is arrived also at the particle–cone contact level. The properties of this dynamic interface are independent of the initial density of the granular material.

3

On the interpretation of seismic cone penetration test (SCPT) results

Bagińska I., Janecki W., Sobótka M.

Studia Geotechnica et Mechanica

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2013

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Vol. 35, nr 4

3--11

EN

The paper deals with the methodology of performing and interpretation of seismic cone penetration test (SCPT). This type of test is used to determine velocity of the seismic wave in the soil medium. This study is focused on shear wave. The wave is triggered on the ground surface by hitting an anvil with a sledgehammer. Then, vibrations induced at different depths are measured. Based on recorded measurements wave velocity (Vs) and thus also small strain shear modulus Gmax may be calculated. An interpretation of exemplary seismic test results is presented. Crossover and cross-correlation methods are discussed and another, more adequate one is featured and then applied in the interpretation example. Conditions for correct test performance and interpretation are discussed.

4

Modelling the cone penetration test by the finite element method

Markauskas D., Kacianauskas R., Suksta M.

Foundations of Civil and Environmental Engineering

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2002

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No. 2

125-140

EN

In the present study, CPT is modelled by static elasto-plastic small strain finite element method (FEM) analysis of axi-symmetric problem. Undrained soil properties and Tresca yield criterion is used for determining cone resistance of clay. Sand is modelled by using drained soil properties and Mohr-Coulomb yield criterion. Cone penetration problem is formulated as a collapse load problem. Associated and non-associated flow rules were used for modelling A number of the numerical experiments were performed to determine rational size of discrete region. Received dimensions of region were used for further research. Cone factor Nc for clay was obtained and the comparison of Nc values with other theoretical solutions is presented. A conclusion may be made that the limit of the validity of geometrically linear systems has been reached. The evaluation of the effect of cone penetration requires the analysis of large strains to be made.

PL

W pracy przedstawiono numeryczne modelowanie zjawiska penetracji stożka w gruncie. Wykonano je, stosując metodę elementów skończonych. Do obliczeń zastosowano teorię małych odkształceń sprężysto-plastycznych. Wyniki podano, wykorzystując w analizie osiową symetrię zjawiska. Badano efekty penetracji stożka w dwóch rodzajach gruntów: w glinie i w piasku. Dla ustalenia oporu penetracji stożka w glinie traktowanej jako grunt odwodniony zastosowano warunki plastyczności Treski. Piasek był modelowany jako grunt nawodniony, do którego opisu zastosowano warunki plastyczności Mohra-Coulomba. Penetrację stożka rozważano jako problem wyznaczenia wartości obciążenia prowadzącego do uplastycznienia gruntu. Otrzymane rezultaty porównano dla przypadków modelowania zjawiska z zastosowaniem stowarzyszonego i niestowarzyszone prawa płynięcia. Celem eksperymentów numerycznych było również określenie maksymalnych rozmiarów strefy gruntu otaczającej stożek, której dyskretyzacja wystarczała do dokładnego opisu zjawiska. Wyniki badań numerycznych porównano z innymi przedstawionymi w cytowanej literaturze. Określono również zakres ważności przyjętej do modelowania teorii małych odkształceń.