基于现场液化试验的砂土孔压与剪应变关系研究

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振动与冲击 ›› 2018, Vol. 37 ›› Issue (18) : 158-164.

论文

付海清1,2，袁晓铭1，汪云龙1

作者信息 +

Pore pressure-shear strain relationship of saturated sand based on in-situ liquefaction tests

FU Haiqing 1, 2 ，YUAN Xiaoming 1 ，WANG Yunlong 1

Author information +

文章历史 +

摘要

采用自行发展的现场液化试验技术与方法，设计完成两种形式的现场试验，研究了饱和砂土液化过程中孔压和剪应变关系，给出了两者关系的定量表达式，并与他人基于动三轴试验、现场液化试验得到的结果进行了对比和讨论。主要认识如下：（1）加速度对饱和砂土孔压与剪应变的关系影响较小，但其影响程度大于相对密度；（2）提出用数学和液化物理过程表达一致的公式 [U=1-exp(aγ+b),U≥0]来定量描述这种关系；（3）当饱和砂土剪应变在0.03~0.3%时，孔压迅速发展。剪应变在0.5%左右时，孔压比达到1。这一结果，与Dobry动三轴试验结果基本一致，而与Chang现场试验结果存在差异，原因是Chang的土体剪应变为有限元方法计算液化大变形而非用实测位移得到。

Abstract

Based on the self-developed in-situ liquefaction testing technology, two different types of in-situ liquefaction tests were carried out.The pore pressure-shear strain relationship of saturated sand was studied and its quantitative expression was presented.Besides, the simulation results were compared with the dynamic triaxial test results and the in-situ liquefaction test results by others.The main conclusions are as follows.The acceleration slightly affects the pore pressure-shear strain relationship of saturated sand, but its influence is larger than that of the relative density.An equation, ［U=1-exp(aγ+b), U≥0］, Which is consistent with the mathematical expression of the physical process of soil liquefaction, was proposed to quantitatively describe this relationship.When the shear strain of saturated sand is at the range of 0.03%~0.30%, the residual pore pressure increases quickly.Furthermore, when the shear strain of saturated sand is about 0.5%, the residual pore pressure ratio can reach the maximum value 1.These results are consistent with those obtained from strain-controlled dynamic triaxial tests by Dobry, but have discrepancy with these obtained from in-situ liquefaction tests by Chang.The unexpected results were analyzed and it is found the discrepancy is caused by the unadapted computation method for shear strain adopted by Chang.In the process of soil liquefaction, large deformation occurs, and it is unreliable to calculate the shear strain by the finite element method.

导出引用

付海清1,2，袁晓铭1，汪云龙1. 基于现场液化试验的砂土孔压与剪应变关系研究[J]. 振动与冲击, 2018, 37(18): 158-164

FU Haiqing 1, 2,YUAN Xiaoming 1,WANG Yunlong 1. Pore pressure-shear strain relationship of saturated sand based on in-situ liquefaction tests[J]. Journal of Vibration and Shock, 2018, 37(18): 158-164

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