Experimental Study On Effects Of Moisture Nur Strong Chlorine Aline Soil Engineering Properties Of Freeze-thaw Cycles Under Onditions

By Nur natural saline soil typical indoor routine tests, a preliminary master Nur typical basic physicalproperties of natural saline soil, and natural saline soil in Lop typical strength properties under conditionsof freeze-thaw cycles carried out research.Tests using strain controlled direct shear apparatus and triaxial instrument for controlling typicalnatural strong chlorine saline soil under optimum water content and a certain degree of compaction of thestate, the sample through different cycles of freeze-thaw direct shear tests. The test results show that: thesample preparation method and hit like compaction method increases the number of freeze-thaw cycles,cohesion increases first and then decreased, internal friction angle showed a growing trend.Direct shear test operation is simple, intuitive, but it can not control the drainage conditions, and thebroken surface is not true shear cut broken face, and triaxial tests can be controlled drainage conditions, thecut surface is real cut-breaking broken surface, so using triaxial compression the method of controlling thedegree of compaction test when the sample was0.95through different freeze-thaw cycles and differentmoisture state triaxial undrained shear and consolidated drained shear tests, which analyze the moisturecontent shear Strength Index freeze-thaw cycles under conditions typical of natural saline, the stress-strainrelationship, volumetric strain and Duncan-Chang model parameters influence. Through trial found thatstrong chlorine saline soil at different moisture content after freeze-thaw cycles and experience differenteffects on the above parameters are the following rules:(1) With the increase of freeze-thaw cycles, cohesion Cu showed a decreasing trend, and reducesmainly concentrated in the first three stages of the process of freeze-thaw cycles, the internal friction angleφu at first increases and then decreases trend.(2) Different moisture and freeze-thaw cycles experienced different conditions, the strong chlorinesaline soil consolidated drained triaxial shear test showed that: strong chlorine saline soil moisture contentunder optimal conditions, the experience each time frozen stress-strain curves thaw cycles to strainhardening based; when the moisture content is less than the optimum water content, experiencestress-strain curve after each freeze-thaw cycles to strain softening dominated; when the moisture contentis greater than the optimum water content when experiencing stress-strain curve after each freeze-thawcycles at low confining pressure showing strain softening at high confining pressure condition showedstrain hardening. Thus we have: strong structural strength with increasing chlorine saline soil moisture andfreeze-thaw cycles decreases.(3) Through freeze-thaw cycles under different conditions, when strong chlorine saline soil moisturecontent is less than the optimum moisture content, the body becomes-strain curves showed after the firstdilatancy characteristics; when strong chlorine saline soil when the moisture content of greater thanoptimum water content, at low confining pressure showed after the first dilatancy characteristics at highconfining pressure performance characteristics continue to shrink shears; when strong chlorine saline soilmoisture content was most when excellent moisture, volume change-strain curves showed continuedcontraction shear characteristics.