Study On Internal Erosion Mechanism Of Gap-graded Soil-rock Mixture

Natural accumulations exist widely in nature,and their failure mechanism under rainfall conditions has always been a hot spot in the research direction of geological disasters.When analyzing the stability under the rainfall condition of the soil-rock mixture slope,due to the extremely uneven material,it often shows intermittent gradation and strong permeability.Therefore,it is necessary to consider the effect of rainwater seepage on the internal particle erosion.This thesis takes the indoor model test as the primary research method and combines the computer numerical analysis software to explore the internal eclipse mechanism of the soil-rock mixture material.The main research results are as follows:?1?A set of equipment for the seepage and erosion model test was independently developed,and the process of dynamically infiltrating the soil sample was carried out under the condition of maintaining a constant head and sample saturation.?2?6 kinds of particle grading materials were subjected to seepage erosion test using the above apparatus.The parameter?P_max is used as an index to judge the degree of particle erosion,the test results show that the total amount of erosion particles is positively correlated with the curvature coefficient of the material.The unevenness coefficient of the material determines the settlement deformation of the sample.There are coarse particle skeleton structure,coarse-fine particle skeleton structure,and fine particle skeleton structure in the material.The sample with a fine particle content of about 30%is a coarse-fine skeleton structure,and the fine particles are most susceptible to infiltration by rainwater,and then migrate to the deep part of the soil,but there is a limit of the moving distance.?3?The osmotic stability of the test materials was evaluated by three different types of discriminant criteria.The results were in agreement with the experimental results,and the osmotic stability of the discontinuous gradation was considered to be poor.?4?The PFC particle flow software was used to establish the natural accumulation slope model,and the numerical simulation method was used to study the influence of fine particle loss on the slope stability.The results show that the loss of fine particles will lead to significant settlement deformation in the middle and lower part of the slope,and the settlement size is positively correlated with the loss of fine particles.The loss of fine particles will change the failure mechanism of the slope,from the original soil-rock contact.Surface slip is turned to slip-settling coupling failure.