Three Axis Shear Deformation Of Loess Experimental Study

Loess as a kind of high structural soil, when the moisture content is low, it can beexcavated and long-term stability under the conditions of not support and without lining, suchas caves in northern Shaanxi. The main reason lies in the loess of insoluble salts on soilparticle cementation. CaCO3is the main component of the cementation of the insoluble salt.The calcium carbonate content in loess has a great influence on the shear deformation andintensity. Loess area many structures Such as earth-rock dam, embankment, roadbed due tothe long-term natural and anthropogenic factors, cracks will appear, landslide, leakage, theloess structure function in severe aging In addition, long-term since research of the loess inthe process of shearing strain localization is not deep enough, just stay in the level ofphenomenological description, Inadequate research on the mechanism. In order to study theformation mechanism of the shear failure and calcium carbonate on the impact strength ofloess, Taking Yangling District loess as the object, in a strain-controlled triaxial apparatus,changing the premise of the soluble salt content of the loess. Comprehensive and detailedrecord of the deformation of the shearing process. Turkey Analysis of the loess rupturecharacteristics of the soluble salt content and cracking behavior by the test data analysis:Therelationship between axial strain and time,Axial strain field map,The relationship betweenthe principal stress difference and time. Analysis the shear failure modes of original state toreshape and prolonged leaching of the loess. Obtained the following results:1)The shear failure pattern of the same soil samples at the condition of high moisturecontent and low dry density most prone to bulging destruction The high density is a necessarycondition for shear zone.2) The same soil samples when the dry density is the same, the same confining pressure,the peak intensity decreases as the moisture content increases When the moisture contentconstant, the same confining pressure, the peak intensity increases with the increase of drydensity The same dry density, the same moisture content, confining pressure is greater thegreater the peak intensity.3) Failure modes of soil samples can be divided into three categories: Uniformdeformation and failure, Shear failure, Bulging damage or neck damage when the calciumcarbonate content decreased the strength of the sample fell. These results will be provide a theoretical basis to the formation of loess long-termsafety analysis and mitigation of loess structures in the "whole life" design theory, theprotection of the Northwest ancient earth buildings.