Study On The Performance Of The Loess EPS Beads-mixed Lightweight Soil

Loess distributes widely in northwest China,and the loess landslide is a kind of the common geological disasters in the distributive area of the loess.Caves and cracks widely distribute on loess tableland area at the south bank of Jinghe River in Jingyang County of Shaanxi Province are development,sometimes can see isolated loess column,known as the karst landform.Caves and cracks can induce the loess landslides,so fill the cave and crack to reduce the occurrence of landslide disaster has a great practical significance.Based on the loess slope at the south bank of Jinghe River in Jingyang County of Shaanxi Provinceas the research object,this paper puts forward a kind of treatment method.The method is that use the loess EPS(Expanded Polystyrene)beads-mixed lightweight soil to fill cracks and caves.The liquidity,strength and permeability of the loess EPS(Expanded Polystyrene)beads-mixed lightweight soilare studied through liquidity test,indoor experiment of shear strength,triaxial permeability test and matrix suction experiment.By the Geo-Studio software modeling analysis,get the optimum mixture ratio of filler material,and provide theoretical basis for prevention of loess landslides,then to implement the purpose of the loess "karst" treatment and improving the stability of the loess slope.The results of the research are the following:(1)The flow capacity of the loess EPS beads-mixed light weight soil increases with the increasing of water mixing ratio,and it decreases with the increasing of cement or EPS particle mixing ratio.Get the prediction formula of the loess EPSbeads-mixed lightweight soil's liquidity.(2)The unconfined compressive strength increases as time goes on.Before 28 days the strength is growing rapidly,and it is a logarithmic function relationship with time;it grows quite slowly after 28 days.The unconfined compressive strengthdecreases with the increasing of cementmixing ratio,and it decreases with the increasing of water or EPS particle mixing ratio.It has power function relationship with different mixing ratio.(3)When the confining pressure phase is at the same time,with the decrease of the water blending ratio or the increase of cement mixing ratio,the stress-strain curve will be created by the strain hardening to the strain softening shape.When the confining pressure is 50-200 kPa,Mohr coulomb theory can be used to analyze the shear strength.When the confining pressure is equal to or greater than 300 kPa,Mohr coulomb theory can't be used to analyze the shear strength.(4)The water mixing ratio has little effect on shear strength.The cohesion increases with the decrease of EPS particle mixing ratio or the increase of cement mixing ratio,but the angle is on the other hand.(5)The order of magnitude of the saturated permeability coefficient is roughly 10-8~10-9.Under the effect of confining pressure,the saturated permeability coefficientwill be smaller.It decreases with the increasing of confining pressure,and it has power function relationship withconfining pressure.It increases with the decreasing of cement mixing ratio or the increasing of EPS particle mixing ratio.The water mixing ratio has no effect on saturated permeability coefficient and the relationship between matrix suction and volumetric water content.(6)By the Geo-Studio software modeling analysis,get the optimum mixture ratio of filler material—Water blending ratio is 70%,cement mixing ratio of 20%,EPS particle mixing ratio of 3%.