累积塑性体应变对非饱和原状Q_(3)黄土动骨干曲线的影响研究  

Study on the influence of accumulated plastic volume strain on the dynamic backbone curves of unsaturated and undisturbed Q_(3)-loess

作　　者：王强[1,2] 张喆[1] 杨谦[1] 邓国华[3] WANG Qiang;ZHANG Zhe;YANG Qian;DENG Guohua(Xianyang Engineering Technology Research Center for Loess Mechanics and Disaster Prevention,Shaanxi Polytechnic Institute,Xianyang 712000,China;Shaanxi Key Laboratory of Loess Mechanics and Engineering,Xi'an University of Technology,Xi'an 710048,China;Xi'an Loess Underground Engineering Technology Consulting Co.,Ltd.,Xi'an 710054,China)

机构地区：[1]陕西工业职业技术学院咸阳市黄土力学与灾害防治工程技术研究中心,陕西咸阳712000 [2]西安理工大学陕西省黄土力学与工程重点实验室,陕西西安710048 [3]西安黄土地下工程技术咨询有限公司,陕西西安710054

出　　处：《甘肃科学学报》2024年第3期77-83,共7页Journal of Gansu Sciences

基　　金：国家自然科学基金项目(52178355);陕西工业职业技术学院博士基金(BSJ2021-08)。

摘　　要：为研究循环累积塑性体应变对黄土骨干曲线的影响,选取典型原状Q_(3)黄土,开展了一系列不同含水率、固结压力和剪应变幅等变化条件下的动单剪试验。试验结果显示,非饱和原状Q_(3)黄土具有明显的循环剪缩和循环硬化特性;骨干曲线形态随循环加载周的变化而变化,变化幅度与累积塑性体应变相关。由此认为,震陷性黄土骨干曲线的构造需要考虑循环加载累积效应的影响,多级加载试验对其是不适用的;震陷性黄土的初始骨干曲线应采用单级加载试验构造,多级加载动骨干曲线需要考虑塑性累积体应变对初始骨干曲线的影响。基于剑桥模型推导的土体孔隙比和抗剪强度的关系式,推导了不同加载周土体最大动剪切模量比和最大动剪应力比与累积塑性体应变之间的关系式,并建立了可以考虑累积塑性体应变影响的动骨干曲线方程,试验验证该方程具有较好的模拟效果。In this study,cyclic simple shear tests were conducted on a series of typically undisturbed Q_(3)-loess specimens under different water contents,consolidation pressures and the amplitudes of shear strain were used to study the influences of accumulated plastic volume strain during cyclic loading.The tests show that the properties of cyclic shear shrinkage and cyclic hardening are distinct for the Q_(3)-loess and the shape change of backbone curve during cyclic loading is mainly relevant to the accumulated plasitic volume strain.It can be thereby concluded that the accumulation effect under cyclic loading need to be considered for constructing the backbone curve of loess once the property of seismic subsidence is strong,and the multi staged loading test is not suitable while dynamic backbone curves is required based on the single staged loading test including the influence of accumulated plastic volume strain.The relation between the accumulated plastic volume strain versus the maximum dynamic shear module ratio and the maximum dynamic shear stress ratio according different loading cycles were derived according to the relation between pore ratio and shear strength in the Cambridge model.Finally,the equation of dynamic backbone curve,could take the accumulated plastic volume strain into account,which was well presented and verified.

关 键 词：非饱和黄土 骨干曲线 动单剪试验 震陷性 单、多级加载试验 

分 类 号：TU443[建筑科学—岩土工程]