摘要
为探求陕西泾阳南塬高速远程黄土滑坡的复活机理,从大型黄土滑坡滑带采集原状黄土试样、古土壤试样(原状土),部分制备重塑试样(重塑土),进行不同体积含水率下的反复剪切试验,从而获得滑带土残余剪切强度指标与体积含水率、黏粒含量之间的关系。结果表明:原状土和重塑土的剪应力-位移曲线均为硬化型;在不同的垂直压力下,原状土和重塑土的残余剪切强度差值变化较大;当剪切强度达到峰值强度以后,随着剪切位移的继续增大,原状土和重塑土的残余剪切强度都有一定程度的损失,这种损失因垂直压力的不同而不同;对同类土,通过反复剪切试验获得的内聚力和内摩擦角随体积含水率的增加而降低;相关性分析表明,该区滑带土的黏粒含量较低,对残余剪切强度的内摩擦角影响很小,尤其是当天然体积含水率较低时,体积含水率的变化对残余剪切强度的影响远远大于黏粒含量的影响。
In order to find the reactivation mechanism of high-speed long-distance loess landslide in Jingyang southern highland of Shaanxi, the undisturbed loess and paleosoil samples were collected from sliding zones of large loess landslides, and the remolded soils were prepared from part undisturbed soils; repeated shear tests under different volumetric moisture contents were designed, and the relationships between indexes of residual shear strength and volumetric moisture content, and cosmid content were discussed. The results showed that the shear stress- displacement curves of undisturbed soil and remolded soil were both hardening type; the difference of residual shear strengths between undisturbed soil and remolded soil was significant under different vertical pressures; when shear strength reached to peak strength, the residual shear strengths of undisturbed soil and remolded soil lost a little with the continues increase of shear displacement, and the loss was different because of the different vertical pressures for the same kind of soils, the cohesions and internal friction angles from repeated shear tests decreased with the increase of volumetric moisture content; correlation analysis indicated that cosmid content was low in landslide soil and had little effect on internal friction angle of residual shear strength, and especially when natural volumetric moisture content was lower, the impact of the change of volumetric moisture content on residual shear strength was significantly more than the impact of cosmid content.
出处
《地球科学与环境学报》
CAS
2012年第4期95-101,共7页
Journal of Earth Sciences and Environment
基金
国家自然科学基金项目(40772181)
关键词
黄土
古土壤
滑带土
原状土
重塑土
残余剪切强度
loess
paleosoil
landslide soil
undisturbed soil
remolded soil
residual shear strength
