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On the numerical modeling of vibratory pile driving in saturated soil In the present report, the vibratory pile driving process in saturated non‐cohesive soil is investigated by means of numerical simulations. For this purpose, two axisymmetric models are created based on different modeling approaches in the FE program ABAQUS/STANDARD. In the first, the pile is not explicitly modeled and the pile‐soil interaction is simplified prescribed by applying a sinusoidal displacement boundary condition at the soil‐pile interface. The second model simulates the vibratory pile driving process more realistically by modeling the penetrating pile as a rigid body subjected to vibrations. For the dynamic analysis of water‐saturated soil the u ‐p formulation has been adopted in both models by using a user‐defined element. A hypoplastic constitutive model with intergranular strain has been selected to describe the mechanical behaviour of the soil. A limited number of cycles has been considered and the focus is mainly placed on the evolution of stresses and displacements in the soil near the pile. The quantitative validation of the applied numerical modeling approaches is based on the comparison with high‐quality model experiments. The extensive and sophisticated instrumentation of the experiments initiate various comparison opportunities. The pile motion, the evolution of the penetration resistance and the occurring soil displacements in the pile vicinity are compared. The good agreement between the results confirmed that the applied simulation methods are able to capture the essential aspects of the mechanism of vibratory pile driving. 相似文献
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《Bautechnik》2017,94(7):459-467
New German Code DIN 4085 – calculation of earth pressure DIN 4085: 2011‐05, first published in 2005, will be replaced in 2017 by a completely revised new version also including new scientific results. The following paper gives an overview and points out essential modifications. 相似文献
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《Bautechnik》2018,95(9):684-692
Report of the committee for recommendations on excavations: Draft of R 85 and annex A 10 – external bearing capacity of soldier piles, sheet pile walls and in‐situ concrete walls In the past, the working group “Baugruben” of the German Society for Geotechnical and Ground Engineering repeatedly received indications from users pointing out the differences in the verification of the vertical load bearing capacity of retaining walls between 4th and 5th edition of the Recommendations on Excavations (EAB). Comparative calculations showed that the verification of the vertical load capacity after the 5th edition leads to less economical results than after the 4th edition. The recommended values for the computational determination of the skin friction could be identified as causal. This was used by the working group as an opportunity to review the current recommendations in detail and to revise them, taking into account scientific findings and practical experience. The subject of this article is the justification for the need for adjustments, the substantiation of the revisions made and the reprinting of the draft of the revised recommendations with a request for comments from experts. 相似文献