干湿循环作用下花岗岩残积土性能劣化及边坡稳定性分析

Property deterioration and slope stability analysis of granite residual soil under dry wet cycles

对不同含水率花岗岩残积土进行了室内抗剪试验,探讨分析干湿循环作用下不同含水率花岗岩残积土的抗剪强度指标的衰减机理和规律,结果表明:含水率越高,初始粘聚力和内摩擦角呈线性降低;随着干湿循环次数的增加,粘聚力呈指数型函数降低,干湿循环对内摩擦角的影响不大;强度衰减曲线符合"S"型曲线,强度损失主要集中于前5次干湿循环。基于研究结果,结合某边坡工程,对花岗岩残积土边坡在降雨和非降雨情况下的稳定性进行分析,结果表明:降雨会加剧花岗岩残积土的损伤劣化累积,导致边坡稳定性迅速降低,干湿循环4次后,安全系数低于1,而在非降雨情况下,经历10次干湿循环后,安全系数仍然大于1。

Based on the indoor shear test of granite residual soil with different moisture content,the mechanism and law of shear strength index attenuation of granite residual soil with different moisture content under the action of dry and wet cycles are discussed and analyzed.The results show that the higher the moisture content,the linear decrease of initial cohesion and internal friction angle is;with the increase of dry and wet cycles,the cohesion decreases exponentially,and the influence of dry-wet cycles on internal friction angle is not obvious.Based on the research results,a case study of a slope stability project of granite residual soil slope under rainfall and non rainfall conditions was carried out.The results show that rainfall will aggravate the damage of granite residual soil,and results in the rapid reduction of slope stability.After 4 cycles of dry and wet,the safety factor is below 1;while in the dry season,after 10 cycles of dry and wet,the safety factor is still beyond 1.