西气东输管道工程子长地区黄土环剪试验研究

Ring-shear Test Research of Loess in Zichang Area along the West-to-East Gas Pipeline Project in China

黄土滑坡是构成西气东输管道安全的重大威胁。本文以西气东输管道工程子长地区的斜坡黄土作为研究对象,通过室内试验研究了该黄土在大剪切位移条件下的力学特征,结果表明:黄土试样在剪切过程中表现出应变软化的特征,并且较快达到残余强度;随着剪切带逐渐形成,黄土试样应力状态发生了改变,其变形也呈现出一定的特征,表现为试样轴向位移经历初始压密阶段、初始剪胀阶段、颗粒破碎压密阶段3个阶段。

Loess landslides constitute a major threat to the safety of the West-East Gas Pipeline Project.Taking the slope loess of West-East Gas Pipeline in Zichang area as the research object,this paper studies the mechanical characteristics of loess by laboratory experiments under the conditions of a large shear displacement.The results show that：loess samples display the characteristics of strain softening in the shearing process,and can quickly reach the residual strength;with the gradual formation of shear bands,the sample stress state changes and its deformation also shows certain characteristics.The axial displacement of the sample undergoes three stages in the shear process： the initial compaction stage,the initial dilatancy stage and the contraction stage due to grain crushing.