Study On Creep Characteristics Of Coarse-grained Soil Of Landslide

Landslidesare one of common geological disasters,whichareseverely destructive.A large number of research data at home and abroad show that the development and evolution of landslides have a time effect,that is,creep characteristics.For some landslides composed of coarse-grained soil,the related research work is more difficult due to the inherent and specific nature of the complex variability of the material composition,the irregularity of the structure distribution and the difficulty in collecting the sample.So the study of creep properties is rare.But in some major projects,long-term stability evaluation and instability mechanism based on creep properties of landslide coarse-grained soil have vital theoretical significance and application value.As a consequence,the coarse-grained soil ofHuaipa landslide in Mianchi County is taken as the research object in thispaper,and the creep characteristics are studied by the large-scale triaxial creeptesting apparatus,and the creep model suitable for the coarse-grained soil of the landslide is established.The details are as follows:(1)The geological characteristics and triggering mechanism ofHuaipa landslide in Chencun Village,Mianchi County were analyzed.A series of indoor physical and mechanical properties tests were carried out on the coarse-grained soil of the landslide to obtain the basic physical property index,grading curve and shear strength parameters of the soil,aiming at providing basis for the loading of the coarse-grain creep test.(2)Thelarge-scale triaxial creeptesting apparatus was used to carry out triaxial creep test under different confining pressures(100kPa,200 kPa,400kPa)and different water stress levels(SL = 0.2,0.4,0.6,0.8).According to the creep curve obtained by the test,the creep characteristics of the landslide were analyzed.Furthermore,the stress-strain isochronal curve was drawn to obtain the long-term strength of coarse-grained soil from the landslide.(3)The Burgers model,Singh-Mitchell model and Mesri model were used to fit the creep curve of landslide coarse-grained soil.The parameters of each model were determined by analyzing the test curves,and the relationship between parameters and stress and time was established.The three model curves were compared to analyze the advantages and limitations of each model.(4)On the basis of the Mohr-coulomb model and the CSVIC model in FLAC 3D,the numerical simulation of the creep properties of coarse-grained soil was carried out onHuaipa landslide of Dianchi County,and the distribution of stress and displacement in the landslidebody and the development of the plastic zone were analyzed.