黄土完全软化强度的试验研究  

Experimental study on fully softened strength of loess

作　　者：强菲[1] 赵法锁[1] 宋飞[1] 

机构地区：[1]长安大学地质工程与测绘学院,西安710054

出　　处：《南水北调与水利科技》2015年第2期302-305,共4页South-to-North Water Transfers and Water Science & Technology

基　　金：国家自然科学基金项目(40772181)

摘　　要：为了准确获取复活蠕滑型黄土滑坡滑带土抗剪强度参数,需要开展黄土的完全软化强度试验研究。以山西黄土为研究对象,采用直接固结法和预压固结法制备饱和重塑试样,并进行了不同剪切速率下的直剪试验和三轴固结排水剪切试验。结果表明:低法向应力下,制样方法对完全软化强度的影响不大,而高法向应力下,预压固结试样的完全软化强度大于直接固结试样;预压固结直剪试验的剪切速率对完全软化强度的影响不大;三轴固结排水剪切试验中,预压固结应力相同时,完全软化强度随围压的增加而增大,围压相同时,完全软化强度随预压固结应力的增加而增大,且应力应变曲线在一定应变范围内重合;黄土的完全软化黏聚力近似为0kPa,预压固结试样的完全软化内摩擦角更接近实际状态。研究结论为复活蠕滑型滑坡稳定性分析中进行强度参数测试时重塑饱和土样的制样方法和试验方法提供了依据。Experimental study on fully softened strength of loess needs to be performed in order to accurately acquire the shear strength parameters of the slip soil in the resurgent and creeping loess landslide.In this paper,direct consolidation method and preloading consolidation method were used to prepare the saturated remolded samples of loess in Shanxi Province for the direct shear tests with different shear rates and triaxial consolidation drained shear tests.Research results showed that（1）the fully softened strength is not affected by sampling methods under low normal stress conditions,but the fully softened strength of preloading consolidation samples is greater than that of direct consolidation samples under high normal stress conditions;（2）the fully softened strength is not affected by the rates of the direct shear tests in which samples were prepared by preloading consolidation method;（3）for the triaxial consolidation drained shear tests,the fully softened strength increases with the increasing of the confining pressure under the same preloading consolidation stress and it increases with the increasing of preloading consolidation stress under the same confining pressure,and the stress-strain curves appear to overlap within a certain range of strain;and（4）the fully softened cohesions of samples are close to 0kPa,and the fully softened friction angles of preloading consolidation samples ae closer to the actual condition.The research results provide reference for the sampling methods and experimental methods of strength parameter tests in the stability analysis of resurgent and creeping loess landslides.

关 键 词：完全软化强度 直接固结法 预压固结法 剪切速率 直剪试验 三轴固结排水剪切试验 完全软化黏聚力 完全软化内摩擦角 

分 类 号：TU411[建筑科学—岩土工程]