Experimental Research On Wetting Deformation And Numerical Simulation Of Unsaturated Latcrite

After initial storage, rainfall or underground water table rising, the materials and core wall of the earth-rock dam will produce wetting deformation because of the lubricating effect of water. This can lead to the crack which is along the axis direction of the embankment dam dam, threatening the anti-seepage function of core wall. Affected by soil moisture change after construction, filled soil also can produce wetting deformation and endanger the normal use of the upper structure. So the research of characteristics of soil materials’ wetting deformation has guiding significance for engineering design and construction. This thesis regards unsaturated laterite of jiangxi area as the studying object, using triaxial apparatus to study complete saturation wetting deformation of unsaturated laterite under different stress path, also applying GDS unsaturated triaxial apparatus to do the partial saturation wetting deformation test and studies the soaking wet deformation law of unsaturated laterite. Based on the existing nonlinear constitutive of unsaturated soils, this dissertation presents the relevant model parameters through combining with the tests in this thesis. The numerical simulation of wetting deformation for roadbed is caculated by using self-compiling program, this simulation considers wetting deformation of unsaturated zone. The main research results are as follows:(1) In the wetting deformation of triaxial apparatus tests, under the same confined pressure, the greater stress level of the sample has more big wetting additional axial strain. Wetting deformation mainly occurs in the early part of wetting process, after that its’ growth rate would reduce. The relationship between wetting additional axial strain and time is approximation hyperbolic. The experience calculating formula of wetting deformation which is about confining pressure and stress level is established through experiments. In the wetting deformation of K0+triaxial apparatus tests, under different wetting stress level the curve of the main differential stress and axial strain are approximation parallel with each other, but the strength of wetting soil reduce.(2) Through the contrast analysis the results of wetting process of The triaxial apparatus stress path,the K0 + triaxial apparatus stress path and the over-consolidated + triaxial apparatus stress, as the stress level increases, additional axial strain of wetting all show a trend of increase. In addition to the over-consolidated specimen whose stress level are over 0.25 and 0.75, other wetting additional volumetric strain of samples both in the range of 0.5 ~ 3.0%.(3) the humidifying experiment is also done by using GDS triaxial apparatus, it is aso nemed part of the saturated wetting tests. It will commonly cost 5 days to achieve deformation stable, the soil moist additional axial strain and volumetric strain can reach about 80% of the total of wetting deformation. In the initial stage of wetting process, the wetting additional axial strain approximately occupies the half of the total wetting additional axial strain. Under the state of a certain net confining pressure and a certain level of stress, the relationship between the matrix suction and volumetric strain is about a hyperbolic function, and there is a linear relationship of soil moisture content and matrix suction.(4) Based on the existing nonlinear constitutive of unsaturated soils, this dissertation establishes the nonlinear constitutive of unsaturated laterite according to the data form referance literature as well as the experimental data of partially wetting deformation.(5) The numerical simulation of wetting effect for roadbed is computed by using self-compiling program, this simulation considers wetting deformation of unsaturated zone which is above saturated zone. The stress and deformation law of the typical filling laterite embankment is achieved under construction and soaking conditions.