非饱和土应力状态变量试验验证研究

发布时间：2018-01-16 14:39

本文关键词：非饱和土应力状态变量试验验证研究　出处：《岩土工程学报》2017年02期 　论文类型：期刊论文

【摘要】：为验证非饱和土两个应力状态变量的合理性,对常规非饱和土三轴仪进行了改进,采用3个压力体积控制器分别控制孔隙水压力、内室压力和外室压力,提高了量测精度。使用改进的非饱和土三轴仪对描述非饱和土应力状态的两个应力状态变量进行系统的试验验证,做了不同初始干密度、不同初始饱和度、不同初始吸力的3组重塑黄土及1组原状Q_3黄土的各向等压试验,试验中等值改变(增加或减少)总围压、孔隙水压力、孔隙气压力而保持应力状态变量本身不发生变化,通过量测试样体积和水量变化分析检验两个非饱和土应力状态变量的合理性。研究结果表明:对于原状Q_3黄土和各种起始条件的重塑土(包括不同密度、不同饱和度及不同吸力的土样),当只改变应力状态变量的个别组成部分而保持两个应力状态变量本身不发生变化时,则土样的体积变化和含水率变化均很小,可忽略不计。研究结果说明描述非饱和土的两个应力状态变量是合理的,使非饱和土的两个应力状态变量理论有了牢靠的试验依据。
[Abstract]:In order to verify the rationality of two stress state variables of unsaturated soil, the conventional unsaturated soil triaxial instrument was improved. Three pressure volume controllers were used to control pore water pressure, inner chamber pressure and external chamber pressure respectively. The two stress state variables describing the stress state of unsaturated soil are systematically tested and verified by using the improved unsaturated soil triaxial instrument. Different initial dry density and different initial saturation are made. Three groups of remolded loess with different initial suction and one group of undisturbed Q3 loess were subjected to isobaric tests in which the total confining pressure and pore water pressure were changed (increased or decreased). The pore gas pressure keeps the stress state variable itself unchanged. The analysis of volume and water change of the sample tested by throughput tests the reasonableness of the two stress state variables of unsaturated soil. The results show that: for the undisturbed Q3 loess and the remolded soil with various initial conditions (including different densities). When the soil samples with different saturation and suction change only the individual components of the stress state variables and keep the two stress state variables unchanged, the volume change and moisture content change of the soil samples are very small. The results show that it is reasonable to describe the two stress state variables of unsaturated soil, which provides a reliable experimental basis for the theory of the two stress state variables of unsaturated soil.
【作者单位】：兰州理工大学土木工程学院;中国人民解放军后勤工程学院;延安大学建筑工程学院;空军工程大学机场建筑工程系;
【基金】：国家自然科学基金项目(11272353,11672330,51309199,51509257)
【分类号】：TU411.3
【正文快照】： 陕西延安716000;4.空军工程大学机场建筑工程系,陕西西安710038)应力状态是研究土力学性质的前提,也是研究土应力应变关系的基础。目前在关于土的应力状态的描述中,Terzaghi提出的有效应力原理解决了饱和土应力状态的描述问题,但对于非饱和土,则出现了多种描述形式,其中包括Bi

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