动态渗透压力作用下粉质黏土强度特性试验研究  

Experimental Study on Strength Characteristics of Silty Clay Under Dynamic Osmotic Pressure

作　　者：王善学 刘燕[1] 杨帆 张树明 周祥 付青华 Wang Shanxue;Liu Yan;Yang Fan;Zhang Shuming;Zhou Xiang;Fu Qinghua(School of Civil Engineering and Architecture,Jinan University,Jinan 250022,China;Jinan Dinghui Civil Engineering Technology Co.,Ltd.,Jinan 250002,China;China Railway 14th Bureau Group Shield Engineering Co.,Ltd.,Nanjing 211803,China)

机构地区：[1]济南大学土木建筑学院,济南250022 [2]济南鼎汇土木工程技术有限公司,济南250002 [3]中铁十四局集团大盾构工程有限公司,南京211803

出　　处：《科技通报》2025年第2期31-38,共8页Bulletin of Science and Technology

基　　金：山东省自然科学基金项目(ZR2022ME042);济南大学博士基金项目(XBS2469);山东省高等学校青创科技支持计划项目(TJY2303);山东省住房城乡建设科技计划项目(2024KYKF-XCJ017)。

摘　　要：济南地区承压含水层受季节性雨水、河流等因素的影响,呈现动态变化特性。本文为探究承压水动态渗透压力作用下济南地区典型粉质黏土强度变化规律,结合变水头自动渗压试验仪、应变控制式直剪仪及扫描电镜(scanning electron microscope,SEM)开展微细观试验,探讨了不同循环渗透次数、不同渗透压力增量下粉质黏土强度弱化规律。结果表明:在循环渗透作用下,粉质黏土的剪应力-剪切位移曲线表现出软化特性,且软化效应随循环次数的增大愈加显著;黏聚力随循环次数的增加持续降低,循环渗透5~20次范围内,黏聚力从31.47 kPa降低到26.23 kPa,降低了16.65%,但循环渗透次数对内摩擦角的影响并不明显。相同循环次数下,渗透压力增量的增大会使土的剪应力-剪切位移曲线由应变软化型向应变硬化型转变,渗透压力增量在20~80 kPa范围内,土体黏聚力由27.63 kPa下降到10.35 kPa,下降了62.54%。渗透压力增量对黏聚力的弱化效应明显高于内摩擦角。微细观试验表明随着循环渗透次数的增加,土体中的细小颗粒在渗透过程中更易于沿着形成的通道流失从而减弱了土颗粒间的紧密连接和相互支撑,导致土的结构发生变化。The pressurized aquifer in Jinan area is affected by seasonal rainfall,rivers and other factors,showing dynamic change characteristics.In order to investigate the change rule of the strength of typical powdery clay in Jinan area under the dynamic infiltration pressure of pressurized water,we combined the variable head automatic infiltration tester,strain-controlled straight shear instrument and scanning electron microscope(SEM)to carry out microfine view test,and explored the weakening law of the strength of powdery clay under the different times of cyclic infiltration and the different increment of infiltration pressure.The results show that:under the action of cyclic infiltration,the shear stress-shear displacement curve of powdery clay shows softening characteristics,and the softening effect is more and more significant with the increase of the number of cycles;The cohesive force decreases with the increase of the number of cycles,and within the range of 5-20 cycles of infiltration,the cohesive force decreases from 31.47 to 26.23 kPa,which is a decrease of 16.65%,but the number of cycles of infiltration does not have a significant effect on the angle of internal friction.For the same number of cycles,the increase of infiltration pressure increment will change the shear stress-shear displacement curve from strain-softening to strain-hardening,and the cohesion of the soil body decreases from 27.63 kPa to 10.35 kPa,which is 62.54%in the range of infiltration pressure increment from 20 kPa to 80 kPa.The weakening effect of infiltration pressure increment on cohesion is obviously higher than the internal friction angle.The microscopic test shows that with the increase of the number of cyclic infiltration,the fine particles in the soil body are more easily lost along the formed channels during infiltration thus weakening the close connection and mutual support between the soil particles,resulting in the structural change of the soil.

关 键 词：承压水 强度变化 渗透循环 粉质黏土 

分 类 号：TU41[建筑科学—岩土工程]