摘要
以贵阳红黏土为研究对象,利用SLB-1型三轴剪渗仪开展了常规三轴固结不排水试验,着重分析固结阶段和剪切阶段土样孔隙水压力的演化规律、试验破坏应力的取值标准、总应力路径和有效应力路径的相互关系;同时,从土样受力状态出发,根据有效应力原理,探讨试样的破坏机理。试验结果表明:孔隙水压力是三轴试验的重要参数之一,控制着土样有效应力强度参数:在固结阶段,随着孔隙体积的压缩,孔隙水压力逐渐消散为零;在剪切阶段,土颗粒经过重新排列后,产生超静孔隙水压力,并随应变的增大而增大,此时有效应力随之减小。在p-q应力空间内,有效应力运动轨迹在总应力运动轨迹的左侧,呈反弯型,孔隙水压力的变化是造成两种不同应力路径特征的根本因素。在孔隙水压力的作用下,应力空间内的点的变化过程有总应力路径和有效应力路径之分,但两种应力状态都可以用莫尔圆来表示,两个莫尔圆在横轴上的间隔即为超静孔隙水压。
This paper presents the conventional triaxial consolidation test results on Guiyang red clay by using SLB-1 triaxial shearing and osmotic apparatus.The evolution of the pore water pressure of soil samples during the consolidation and shearing stages,the value of the test failure stress,the relationship between the total stress path and the effective stress path are observed and evaluated.Meanwhile,the deformation failure mechanism of samples is analyzed from the effective stress principles.The test result show that,the pore water pressure is an important parameter of triaxial test,which controls the effective stress intensity of soil sample.Specifically,in the consolidation stage,with the compression of the pore volume,the excess pore water pressure gradually dissipates to zero.In the shear stage,after the soil particles are rearranged,the excess pore water pressure is generated and increases with the increase of strain.At this stage,the effective stress decreases.In the stress space,the effective stress trajectory is on the left side of the total stress trajectory,which is reverse bending.The variation of the pore water pressure is the fundamental factor that causes the characteristics of the two different stress paths.Under the action of the pore water pressure,the change process of points in the stress space can be divided into the total stress path and the effective stress path,but both stress states can be represented by Mohr circles,and the two Mohr circles are on the horizontal axis.The interval is the excess static pore water pressure.
作者
赵蕊
李小林
ZHAO Rui;LI Xiaolin(Weinan Vocational and Technical College,Weinan 714000)
出处
《土工基础》
2022年第5期771-774,781,共5页
Soil Engineering and Foundation
基金
陕西省教育厅专项科研计划(19JK0301)。
关键词
红黏土
固结不排水
孔隙水压力
有效应力
总应力
破坏机理
Red Clay
Consolidate Undrained
Pore Water Pressure
Effective Stress
Total Stress
Failure Mechanism
