基于现场液化试验的砂土孔压与剪应变关系研究  

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

作　　者：付海清[1,2] 袁晓铭[1] 汪云龙[1] FU Haiqing;YUAN Xiaoming;WANG Yunlong(Institute of Engineering Mechanics,China Earthquake Administration Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration,Harbin 150080,China;Shandong Earthquake Agency,Jinan 250014,China)

机构地区：[1]中国地震局工程力学研究所,中国地震局地震工程与工程振动重点实验室,哈尔滨150080 [2]山东省地震局,济南250014

出　　处：《振动与冲击》2018年第18期158-164,共7页Journal of Vibration and Shock

基　　金：中国地震局工程力学研究所基本科研业务费专项(2018A01);国家重点研发计划政府间国际科技合作重点专项(2016YFE0105500);国家自然科学基金(51508533)。

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. 30%时,孔压迅速发展。剪应变约0. 5%时,孔压比达到1。这一结果,与Dobry等的动三轴试验结果基本一致,而与Chang等的现场试验结果存在差异,原因是Chang等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。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.

关 键 词：砂土液化 现场试验 孔压 剪应变 

分 类 号：TU41[建筑科学—岩土工程]