荷载与干湿循环协同作用下红黏土变形特性及裂隙扩展规律研究

Deformation characteristics and crack propagation law of red clay under the synergistic effect of load and dry-wet cycle

为了研究不同初始含水率、压实度、上覆荷载和干湿循环次数对红黏土变形特性及裂隙扩展规律的影响,采用改进后的固结仪装置对贵州红黏土进行施加上覆荷载的干湿循环试验,定量分析其变形性能与裂隙发育。结果表明:提高初始含水率、施加上覆荷载、减小压实度可以有效降低红黏土的胀缩变形,施加上覆荷载时,红黏土胀缩变形幅度随干湿循环次数的增加而减小;红黏土变形特性的影响程度依次为上覆荷载、压实度、初始含水率、干湿循环次数;红黏土裂隙发育与初始含水率、压实度、上覆荷载呈负相关,与干湿循环次数呈正相关;红黏土绝对胀缩率与裂隙率、压实度可通过二元非线性函数关系拟合。

In order to study the effects of different initial moisture content,compaction degree,overlying load and the number of dry and wet cycles on the deformation characteristics and crack propagation law of red clay,an improved consolidation instrumentwas used to conduct dry and wet cycle tests with overlying load on red clay in Guizhou,to quantitatively analyse its deformation properties and fissure development.The results show that increasing the initial moisture content,applying the overlying load,and reducing the degree of compaction can effectively reduce the expansion and contraction deformation of red clay.The degree of influence on the deformation characteristics of red clay is in the order of overlying load,compaction degree,initial moisture content,number of dry-wet cycles.The development of fissures in red clay is negatively correlated with initial moisture content,compaction,and overlying load,and positively correlated with the number of dry-wet cycles.The absolute expansion and contraction rate of red clay,the crack rate and the degree of compaction can be fitted by a binary nonlinear function.