Study On Degradation Characteristics Of Laterite Model Dam Slope Under Dry And Wet Cycles

This paper takes Yunnan laterite as the research object,combined with the impact of Yunnan extreme drought and rainy season frequent alternation of wetting-drying cycle and the action on Yunnan laterite dam slope,put forward the topic of "research" deterioration model of laterite dam slope under wetting-drying cycle.The indoor clay dam slope model test based on reservoir water level fluctuation as dry wet cycle control conditions,combined with the method of micro macro test,study the dry wet cycle process model of clay dam slope slope deterioration,soil water pressure change characteristics,shear strength,compression properties and corresponding microstructure characteristics,analysis of red clay the model of dam slope degradation characteristics.The research achievement has important significance for disease prevention and control of the actual dam of laterite.The results show that the soil pressure decreases and the pore water pressure increases in the process of moistening and wetting,and vice versa.With the increase of the number of wetting-drying cycle,the soil pressure of the laterite mass is reduced and the stability trend is lower when the slope height is low.The pore water pressure increases with the increase of dry wet cycles.Wetting-drying cycle process of reservoir water level fluctuation in the water caused by repeatedly moving in and out of the water swelling and shrinkage further intensifies,laterite dam slope shows a concave slope cracking,spalling,Pojiao bulk particle packing under convex slope contour changes,change the slope body contour shape clay slope,there dam slope deterioration.By carrying out the wetting-drying cycle of dam slope laterite macroscopic characteristics of test showed that the wetting-drying cycle and reduce the percentage of laterite slope,water content increased first and then decreased.The dry density decreases and the shear strength decreases,compression performance increases.With the increase of dam slope elevation,the percentage of clay content decreases,the water content decreases,the dry density decreases,the shear strength decreases,and the compressive strength increases.The shear strength and compressive strength increased with the increase of dry density.Through the test of dam slope laterite microstructure characteristics under wetting-drying cycle shows that the effect of wetting and drying cycles under dry wet circulation model,dam slope gradually deterioration,reduce the aggregate structure,fine particles increased,the soil became loose,increasing the porosity,fractal dimension,the number of particles,the effect of slope elevation.The greater the height of dam slope,soil is loose,the deterioration is serious,the porosity and the fractal dimension,the greater the number of particles,the dry density under the influence of dry density is larger,the more dense the soil deterioration,to a lesser extent,porosity,fractal dimension,a number of smaller particles.Under the condition of dry wet cycle,the slope of model dam gradually deteriorates,and there is a certain relationship between the macro and micro characteristics of dam slope.Dry wet cycling,water softening,chemical dissolution of the dam slope soil,hydration membrane thinning,crack and dam slope gradually weakened the characteristics of cementation,dam slope strength decreased,the dam slope is the reservoir water level dry wet cycle,poor rainfall,dry and wet environment storm and freezing thawing environment negative,provide some references for the project.