不同侧限条件下红黏土竖向压缩性能响应试验分析

Response Test Analysis of Vertical Compression Performance of Red clay under Different Confining Conditions

以江西省南昌市典型红黏土为研究对象,通过控制侧限条件和试样含水率实施竖向压缩试验。系统研究了各侧限工况下红黏土强度和变形特征的响应规律。研究结果表明:无侧限、单面、邻面和对面侧限状态的应力-应力关系可划分为四个阶段:(1)压密和弹性变形阶段;(2)非线性强化阶段;(3)软化阶段;(4)稳态流变阶段。抗压强度、残余强度、峰值应变都随着初始含水率的增大呈非线性增加。而三面和四面侧限条件下红黏土抗压强度整体上试样的抗压强度随含水率的升高而降低。在竖向压缩下,裂纹扩展、贯通,形成宏观纵向裂缝,呈现出明显的劈裂破坏特征。含水率一定时,红黏土峰值强度在各侧限条件的大小关系是:单面侧限<无侧限<邻面侧限<对面侧限<三面侧限<四面侧限。

Taking Jiangxi city in Nanchang Province, the typical red clay as the research object, through the control of unconfined conditions and sample water content to implement vertical compression test system were of responsed of red clay strength and deformation characteristics of the confined conditions. The results show that confining condition free, one profile confining condition, adjacent profile confining condition and opposite profile confining condition state - stress relationship can be divided into four stages ： （ T） compaction and elastic deformation stage,② strengthen nonlinear stage,？ softening stage, @ stable state rheological stage. Compressive strength, residual strength, peak strain with both the initial moisture content increases non-linearly increases. The compressive strength of the whole sample compressive strength of red clay under three and four confining conditions with increasing moisture content decreases in the vertical compression, crack,through,forming a macroscopic longitudinal fissure, showing a significant splitting failure characteristics. When the water content is constant, the peak intensity of the red clay on each side of the relationship is the size limit of the condition ： one profile confining condition 〈 confining condition free 〈 adjacent profile confining condition 〈 opposite profile confining condition 〈 three profile confining condition 〈 four profile confining condition.