摘要
为了研究液化过程中饱和砂土孔隙结构的变化规律,基于砂土的孔隙结构与其电阻率之间存在定量关系的基本认识,自主研发了动三轴液化电测试验设备,建立了变高度等体积试样的电阻率计算方法,开展了不同相对密度和循环荷载幅值下饱和砂样的液化电测试验。结果显示:循环荷载作用初期,电阻率波动不明显,在孔压比较高、动应变出现较大波动时,饱和砂土试样的电阻率才出现明显的波动响应;循环末时刻的电阻率变化量随动荷载振次的增多而下降,并可划分为3个阶段:平稳下降阶段、快速下降阶段和缓慢下降阶段,且受到试样相对密度和动荷载幅值的显著影响;循环末时刻的电阻率变化量与孔压比存在反比函数关系,并在初始液化后继续减小。基于上述测试结果,探讨了液化过程中饱和砂土存在孔隙结构变化的规律性,为砂土液化过程数值模拟获得的细观结构变化规律提供试验依据。
In order to investigate the changes of pore structure of saturated sand during its liquefaction,an equipment for testing the electrical resistance of samples based on the dynamic triaxial equipments is independently developed based on the general understanding of the quantitative relationship between the pore structure and the electrical resistivity of sand.The electrical resistivities of samples with different relative densities under varied cyclic amplitudes of loading are tested,adopting the method for calculating the electrical resistivity of a sample with variable heights and invariable volume established.The experimental results show that the fluctuation of the electrical resistivity is not obvious at the initial stage of cyclic loading,and gradually more violent fluctuation when the pore pressure of the sample is relatively high and the dynamic strain fluctuation is relatively large.The amount of resistivity variation at the end of each cycles,which is affected by the relative density of the sand sample and the amplitude of dynamic load,decreases with the increase of vibration number and can be divided into three distinct stages:steady decline,rapid decline and slow decline.It is also inversely proportional to the pore pressure ratio,and continues to decrease after the initial liquefaction.Based on these test results,the specific regularities of pore structure changes in saturated sands during liquefaction are discussed.This study facilitates the understanding and evaluation of the liquefaction behavior of saturated sands from the perspective of pore structure changes.
作者
王炳辉
李松星
李炎
张雷
金丹丹
袁志华
WANG Binghui;LI Songxing;LI Yan;ZHANG Lei;JIN Dandan;YUAN Zhihua(School of Architecture and Civil Engineering,Jiangsu University of Science and Technology,Zhenjiang 212000,China;Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,China;Qingyuan Zhicarbon Technology(Hefei)Corporation,Hefei,230000,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2023年第S02期25-30,共6页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51978317)
江苏省自然科学基金青年基金项目(BK20200996)。
关键词
饱和砂土
循环液化
电阻率
相对密度
循环加载
saturated sand
cyclic liquefaction
resistivity
relative density
cyclic loading
作者简介
王炳辉(1980—),男,博士后,副教授,主要从事土动力学及测试技术研究。E-mail:wbhchina@126.com;通信作者:张雷(E-mail:lei.zhang@just.edu.cn)。
