Research On Formation Mechanism Of Landslide Induced By Typhoon Rainfall And Prevention Strategy Of Road Slope

China is one of the countries with the most serious landslide disasters in the world.There are great many of factors that cause landslide disasters.As the so-called "ten landslides are nine coursed by water",This shows rainfall is the most critical reason to induce landslides.According to statistics,more than 90% of landslides are due to rainfall.Zhejiang Province is located in the southeast coastal area in China and it is one of the provinces where are most seriously affected by typhoon.The high occurrence period of typhoon disasters is from July to October every year.Due to the wide distribution of soft soil in Zhejiang,landslides frequently occur under the attack of typhoons and rainstorms.Although many researchers have done a lot of in-depth research on rainfall-induced landslide for a long time,there are still some horrible landslides cannot be avoided.Therefore,the research on rainfall-induced landslide needs to be more intensively and meticulously.This paper mainly studies the rainfall-induced landslide based on S10 highway K122 slope.Using LEM and FEM both to analyze the stability of the K122 slope,and propose the prevention strategy of the S10 K122 slope.The main contents and results of this paper are conclusions as follows:(1)Collecting a number of domestic and literature to discuss the types of landslide instability and the mechanism of rainfall-induced landslide.Summarizing the knowledge of mechanical properties of unsaturated soils to expound the characteristics of two most common soil-water characteristic curves and the permeability function,such as VG model and FX model(2)Describing the geological and meteorological conditions in the landslide area,and building a numerical model in actual situation.Using the back calculation method to check the shearing strength parameters of soil combined with the field conditions and civil engineering experience.The position of the sliding surface was determined by using LEM and FEM both.(3)Make use of the Seep/W module to analysis the seepage of the slope in 0 to 15 days under rainfall condition.The result shows that Large amounts of water appear at the bottom of the slope because of the poor permeability.In addition,the actual water infiltration is than than the rainfall intensity due to the damage of the cut-off chute at the top of the mountain.(4)Uniting the Morgenstern-Price limit equilibrium method and unsaturated soil mechanics theory to analysis the stability of the slope.Make use of the Slope/W module to calculate the safety factor of the slope in 0 to 15 days combine with Seepage results.The results show that Under natural conditions,the slope safety factor is 1.16 which is basically stable,however,in the case of rainfall,the slope safety factor will significantly decrease to 1.01,which is in a critical state.Both of them are lower than the standard requirements,that means there is a risk of landslide under the rainfall condition.(5)According to the results of seepage analysis and stability analysis,a series of efficient treatment schemes are put forward.Such as: drainage pipe,intercepting groove,unloading,anchor cable and so on.(6)The methods of numerical simulation,probability analysis and monitoring system are used to evaluate the slope reinforcement plan.The results show that the slope safety factor under dry conditions is 1.36 and the slope safety factor under rainfall condition is 1.22 when the slope after supporting.Both of them are up to the standard requirements.That means this plan is scientific and effective.