| In actual engineering,engineering problems caused by external factors change are often uncommon.Among them,rainfall infiltration and drainage conditions are two common conditions.Rainfall infiltration will cause changes in soil moisture.Differences in drainage conditions(drainage,undrained and partial drainage)will cause the soil to exhibit different mechanical properties,both of which may cause engineering problems.Therefore,it is of great theoretical and practical significance to study the hydraulic characteristics of humidification deformation under the conditions of water infiltration and the asymptotic state under dif,ferent drainage conditions.To this end,this paper takes the remolded loess as the research object,uses the one-dimensional transient soil column permeameter to carry out the soil water infiltration test,and uses the triple consolidation instrument and the permeameter to carry out the conventional compression,penetration test,and the triaxial shear test under different drainage(water absorption)conditions was carried out by using GDS triaxial instrument for unsaturated soil.The effects of dry density and vertical pressure on compression and humidification deformation,water retention behaviors and water permeability behaviors of unsaturated remolded loess were studied.The effect of drainage conditions on the mechanical properties of saturated remolded loess.The main work and research results are as follows:Under the confinced conditions,for the remolded loess samples with the same water content and different dry density,the soil water infiltration test was carried out under different vertical pressures.At the same time,the coinvenlional compression test wzas carried out on samples with different water content and dry density,and the penetration tests were carried out on different dry density saturated samples.The effects of dry density,water content and test methods on compression characteristics and humidification deformation characteristics were analyzed.It was revealed that the compression index of soils measured by soil column compression test is smaller than that of conventional compression test,but the test method is for elastic index and yield pressure.The influence of the test method on the saturated water permeability coefficient was analyzed.It was revealed that the dry density and vertical pressure have a greater influence on the water retention curve with the relationship between water content and suction,the relationship between saturation and suction,and the water permeability curve with the relationship between water permeability and saturation and suction,However,it has little effect on the relationship between saturation and suction ratio,water content ratio and suction,the relationship between relative water permeability coefficient and saturation and suction,and can be approximated;Furthermore,the same humidification and water retention modified VG model and water permeability model considering the effects of dry density and vertical pressure are constructed.Different drainage conditions were simulated by controlling different strain increment ratios.Triaxial shear tests were carried out on different dry density saturated remolded loess samples under different confining pressure and strain increment ratios.The effects of dry density,confining pressure and strain increment ratio on stress-strain behavior,effective stress path and asymptotic behavior of saturated remolded loess are analyzed.And it is revealed that when the dry density and confining pressure are constant,as the strain increment ratio increases,the stress-strain curve shifts upward,the linear shape changes from strong softening to strong hardening,and the pore pressure curve is opposite;The effective stress path at different strain increment ratios is completely different from conventional consolidation drainage and undrained shear tests.The slope of the asymptotic state line of the deviatoric stress and the net average stress decreases with the increase of the strain increment ratio.The asymptotic state line of the void ratio and the net average stress is positive in the strain increment ratio.The time(partial water absorption)is substantially parallel to the critical state line,and when the strain increment ratio is negative(partial water absorption),it gradually moves downward as the strain increment ratio decreases.Finally,the relationship between the final stress ratio and the strain increment ratio is obtained,which could consider the bond stress of saturated remolded loess.And it can be described by the asymptotic equation for sand,the test point fits well with the formula line. |
