柳家凹黄土滑坡滑带土残余强度特性研究

摘要

Liujiaao landslide is the revival ancient landslide,and the sliding zone is the red clay layer located between loess layer and conglomerate layer.Under the action of cutting excavation disturbance and underground water,the property of sliding soil was weakened and the landslide occurred.Indoor repeated direct shear test was carried out by sampling the undisturbed and disturbed soil at the sliding zone,then the strength attenuation characteristics thereof was studied on condition of large shear displacement,and the residual strength index obtained.The paper made the statistics on the peak strength and the residual strength of the soil specimen and,as the result,the residual strength of the sliding soil is far less than the peak strength,i.e.cr is about 0.4 times of cf,and (φ)r about 0.7 times of (φ)f.%柳家凹滑坡为古滑坡复活型,滑动带位于黄土层与砾岩层中间的红色黏土层,由于路堑开挖扰动和地下水作用使滑带土性质弱化造成了滑坡的发生.取滑带土的原状土样试件和重塑土试件进行室内反复直剪试验,研究了大剪切位移条件下滑带土的强度衰减特性,获得了滑带土的残余强度指标.对试验土试件的峰值强度和残余强度进行统计,结果为滑带土的残余强度远小于其峰值强度,cr约为cf的0.4倍,(φ)r约为(φ)f的0.7倍.