Experimental Research On Strength And Deformation Characteristics Of Unsaturated Laterite

This paper chooses Jiangxi unsaturated laterite as the research object, and tries tostudy its strength and deformation characteristics through a series of experiments,which include consolidated drained triaxial tests and constant water content triaxialtests completed by the GDS unsaturated triaxial apparatus, and wetting tests by theimproved conventional triaxial apparatus. The main contents are as follows.(1) Through the soil-water characteristics research, this paper concludes that thesoil moisture content will decrease with increasing matric suction and net confiningpressure, and tries to put forward the surface fitting formula considering the impact ofdual factors.(2) The shearing strength parameters of unsaturated laterite are calculatedthrough the tests. We have found that ’has nothing to do with the matrix suction,and bis non-linear and smaller than ’. And based on that, we are trying topropose the consolidation shearing strength formula. By studying the stress-straincharacteristics, we have found that the unsaturated laterite specimen would hardenunder high confining pressure in the consolidated drained triaxial tests, while it wouldsoften under high confining pressure and low matrix suction condition in the constantwater content triaxial tests. In addition, this paper analyzes the impact rules of netconfining pressure, the matrix suction and moisture content on the shearing strength,and puts forward the corresponding fitting formula based on the single factor and dualfactors. The non-linear model of Jiangxi unsaturated laterite is put forward as well.(3) This paper analyzes the relationships between the volume strain, radial strainand axial strain of unsaturated laterite in the consolidated drained triaxial tests andconstant water content triaxial tests. In the constant water content triaxial tests, theunsaturated laterite specimen would become inflated obviously while being shearedunder the condition of high confining pressure and low matrix suction.(4) This paper analyzes the variation rules of wetting deformation with time, andthen puts forward the correlation formula on the wetting deformation and time.