Research On The Influence Of Muddy Water Seepage On The Permeability Characteristics Of Coarse-grained Soi

Coarse-grained soil is widely distributed in nature.It is the basic material of embankment,foundation,slope and other buildings.It is also an important part of deep overburden.Its pore structure is developed and belongs to high permeability material.The anti-seepage design of such materials in engineering is difficult and costly,but the water body often bypasses the anti-seepage system,and the water storage in the reservoir area cannot meet the design requirements,resulting in leakage and piping.The fine particles of muddy water can be retained and deposited in coarse-grained soil under the action of seepage,which can effectively change the permeability of the original medium layer,and has important practical significance and theoretical value for improving the above problems.In this paper,the coarse-grained soil is taken as the research object,and the method of combining theoretical analysis and laboratory test is adopted.The related research is as follows:（1）Based on Darcy’s law,the theory of muddy water seepage of coarse-grained soil in circular tube is deduced according to the fact that the particles in muddy water are smaller than the pore diameter of coarse-grained soil and larger than the pore diameter of coarse-grained soil.（2）The muddy water seepage test of non-cohesive fine sand particles was carried out,and the permeability curves of coarse-grained soil under different water heads,concentrations and non-uniformity coefficients were obtained.The seepage process of muddy water in coarse-grained soil under the condition of water conservancy and geometric conditions was further studied.（3）The muddy water seepage test of cohesive soil was carried out,and the curves of the overall permeability coefficient and the permeability coefficient of each medium layer of coarse-grained soil with different clay particle content changes(control particle size d_0.075)were obtained.The effects of control particle size,water head and non-uniformity coefficient of coarse-grained soil on the porosity and permeability coefficient of coarse-grained soil were analyzed,and the clogging morphology of coarse-grained soil with control particle size changes was explored.Furthermore,the influence of fine particles of medium and silt,clay and loam on the permeability of coarse-grained soil is further studied.Based on the error between the experimental and theoretical permeability coefficients,the theoretical calculation formula is modified.（4）Through the seepage test of infiltration angle change,the migration-deposition law of fine particles in muddy water in coarse-grained soil after different infiltration angles,initial seepage velocity and concentration seepage was analyzed.The effects of three conditions on the penetration of fine particles were studied,and the migration-deposition mechanism of fine particles in coarse-grained soil was revealed.