The Study Of The Lightweight Loess-EPS Beads Soil Preventing The Seepage In Cracks And Holes Of Loess Slope

The loess landslide is one of the most common geological disasters in the Loess Plateau.There are two factors in the formation of the landslide.First,the external stress causes the loess slope to lose the original stress equilibrium state.Second,the influence of the external environment leads to the occurrence of the shear strength of the loess Change and the inability of maintaining the original stress balance state,which results in landslides.Rainfall and irrigation are the most important factors which lead to the occurrence of geological disasters in the loess landslide.The cracks and holes on the Loess plateau,which are formed in different scale,different sizes,different periods,can the preponderant channel which allows the rainfall,irrigation and other surface water to infiltrate quickly.The surface water converges to the dominant seepage channel,and quickly enters the interior of the Loess Plateau,which results in a significant increase in the groundwater level in the loess plateau slope and promotes the development of the potential sliding surface,so that the landslide occurs.Frequent landslides will not only cause a lot of casualties and property damage,but also make the loss of valuable land resources,which can restrict the local economic development.The annual rainfall on the Loess Plateau is not large,but the rainfall is quite concentrated;meanwhile there are two rounds of irrigation on the Loess Plateau every year,and the irrigation methods are flooding so that in a short period of time,a lot of water along the cave cracks into the slope.Therefore,it is of great theoretical and practical value to study the characteristics of loess flow and the stability of loess slope stability by blocking the flow of preferential flow.In this paper,the EPS lightweight mixed soil was used to make EPS,and the strength properties of the materials and the effect of the wet and dry cycle on the samples were measured.The EPS lightweight mixed soil was applied to the loess plateau filling,and the finite element software GEO-studio was used to simulate the seepage flow in this case,and then the slope stability calculation was carried out to determine whether the crack was filled with EPS Expected purpose.Through the above research and test,the following research results are obtained:1.EPS light mixing ratio,when the cement content is increased,the compressive strength of the material will be raised,the damage will reduce the strain,and the cohesion will be improved.The sample of cement content is less influenced by the wet and dry cycle;the change rate of the size will also lower when it is dry.The increase of the water content will reduce the compressive strength of materials,and damage will increase the strain.When thereis 50% water content,the cohesion reaches to the highest value,but too much water will lead to the increasing water content in the loess and the reduce of the stability of the material,which results in the increase of the dry and wet cycle intensity attenuation rate.The main function of EPS particles is to reduce the density of the material.The compressive strength of the sample is the lowest when the addition amount of EPS is 3%;the cohesive force of the sample is the highest when the incorporation ratio is 1%.The larger the particle incorporation ratio of the EPS is,the larger the declining rate of the wet and dry cycle strength.The formation will be the least when the size variation rate of is up to the lowest.The size of the EPS particles mainly affects the uniformity of the material;in the larger sample of the particle size,the stress intensity will be reduced.The intensity of the wet and dry cycle decay rate will decline with the increase of the particle size,and the The size change rate of drying is the lowest when the particle size is the smallest.2.EPS light mixed soil after wet and dry cycle will lead to the lower performance of the material.After the first wet and dry cycle,the mechanical properties of the material decreased the most dramatically,and subsequently the reduction extent is reducing and the material properties tend to be stable.3.The influences of the irrigation water and rainwater and other surface water infiltration on the stability of the slope is more obvious.After irrigation,the change of pore water pressure in the deep and both sides of the crack is the most obvious.The finite element software can clearly see the change of pore water pressure around the crack.The EPS light-weight mixed soil was filled into the cracks,and then the seepage simulation was carried out.It was observed that the pore water pressure had a great change when compared with that without filling.The filling of the fractures eliminated the accumulation of pore water pressure caused by the preferential flow and improved the porosity of the slope Water pressure distribution.Through the SLOPE / W slope stability calculation results,the safety factor of the slope stability is obviously improved after filling the cracks,which shows that the stability of the slope is obviously improved by filling the cracks with EPS lightweight mixed soil.After filling the cracks with the EPS light-weight mixed soil,the calculation of the transfusion and the slope stability was made,and the slope stability safety coefficient was achieved.Compared with the EPS lightweight mixed soil,the seepage and slope stability were calculated respectively.The safety factor of the slope stability was obtained.The results showed that the cohesion and dry weight of the EPS light mixed soil were influential on the safety coefficient.With the increase of the cohesive force of the EPS lightweight mixed soil,the stability safety coefficient of the loess slope increases.With the increase of the dry weightof the EPS lightweight mixed soil,the stability factor of the loess slope decreases.