Analysis Of Seepage Stability Of Xigeda Soil Back-fill Slope In Different Saturation

This thesis takes project that it is arch dam slope of football field in Panzhihua University,based on regional profile,hydrogeological conditions,artificial lake storage operation mode feature selection of Xigeda soil,lime soil and sand as similar material in the glass box(length * width * height =1800mm * 800 mm * 900mm)produced similar geometry ratio(length)physical model of C=30 slope(1340mm * 800 mm * 833mm),simulation of slope water in different soil under seepage head rate,permeability coefficient and seepage flow and infiltration process of critical water seepage line cracks or instability with time variation and slope rate,at the same time ABAQUS software for strength reduction on the slope seepage stability under different working conditions by using numerical analysis to draw the following conclusions:(1)In different seepage water head condition,unit time with larger slope seepage flow increased,and nearly linear increase.The seepage flow per unit time increases first with the increase of time,then decreases,and finally reaches the stability.The greater the seepage water head is,the greater the peak value of seepage flow is.The seepage flow per unit time increases with the increase of water head.(2)The piezometric head and seepage distance relationship in different seepage head under the action of changing trend is consistent,is steadily decreased with increasing distance to a certain flow,then flow distance is suddenly dropped,short distance flow high water head pressure measuring tube,the distance is low,and the greater the piezometric gradient the water seepage regardless of distance are higher.A total of four wetting lines were drawn during the seepage process.(3)When the slope is under seepage,the time required for the stability of the seepage from the low head to the high head slope is shorter and the time varies greatly,which is determined by the 31h-6h.Secondly,the volumetric water content of soil increases first with the increase of time,then reaches the stability,and the change of water content sensor is consistent.The moisture content at the bottom and upper part of the slope is higher than that of the middle part.(4)The slope began to crack in the saturation reached 0.88,when the saturation reached0.90 at the local began to collapse,when the saturation is 0.92,slope cracks throughout the width of slope instability when the saturation is 0.97.(5)Soil saturation has a great influence on soil cohesion.When soil mass reaches saturation,cohesion is close to zero,and soil internal friction angle is not affected by saturation.The slope safety factor decreases rapidly with the increase of saturation,and when the soil reaches saturation(0.95),the slope loses stability,and the slope safety factor decreases by 64.6%.(6)Finite element slope in backfill under seepage stability of Xigeda soil by strength reduction method using ABAQUS analysis software,analysis results show that the Xigeda soil cohesion and internal friction angle on shear strength under seepage reduction decreased rapidly,the reduction rates were 79.6% and 82.2%,Xigeda the soil backfill slope under different water saturations safety coefficient decreased greatly.(7)The horizontal displacement model test results of slope deformation under different water head are consistent with the numerical simulation results.The maximum horizontal displacement of model experiment is 45.9cm,the maximum horizontal displacement of numerical simulation for 38.78 cm,the difference of 7.12 cm rate is 15.5%;the simulation results consistent with the safety coefficient of backfill model test and numerical slope in different head under the action of Xigeda soil is decreased with the increase of water head,but the two big differences.