多次干湿循环对红土裂隙性和力学特性影响

Effect of multiple wetting-drying cycle on the fracture and mechanical properties of laterite

为了对多次干湿循环后的红土裂隙和强度特性进行分析,对红土进行了最多为25次的干湿循环,统计分析了土样的裂隙发展规律,并对土样在不同次数干湿循环下的的强度参数进行了试验。结果表明:1)干湿循环效应会增加土的裂隙发育,至第5~6次时,裂隙度增加速率虽放缓;至第15~20次之后,裂隙度基本不再增长。2)在前5~6次干湿循环过程中,黏聚力和内摩擦角都随着干湿循环的增加而降低;干湿循环进行到10次后,土体强度参数基本不再变化。3)土体的强度参数与裂隙度关系密切,随着裂隙的增加发展,土体黏聚力、内摩擦角均有所降低,当干湿循环效应不足以引起裂隙度增加或增长缓慢时,土体强度参数也基本保持不变。

In order to research the fracture and mechanical properties of laterite after multiple wetting-drying cycles, up to a maximum of 25 times cycles were conducted,with the developing pattern of fracture statistically ana- lyzed and mechanic parameters tested under different times of circulation.The results indicated that：. 1 ） Wetting-dr- ying cycles can accelerate the propagation of fracture,which by 5-6 times slowed down a bit and by 15-20 times reached constant ;2） cohesion and inner friction angle of the clay decreased as the circulation goes on for the previ- ous 5-6 times and reached constant after 10 times;3） both cohesion and inner friction angle decreased with the propagation of fracture, and stay nearly fixed while the circulation effect can no longer impact, exemplifying the close relationship between laterite＇ s mechanical parameters and its fracture degree.