Stability Analysis Of Cutting Slope Of Red Clay In Hengshao Expressway

With the rapid development of expressway in our country,the development and construction of expressway in our country had been confronted with some critical technologies,one of which was the stability analysis and protection technology research of slope in mountainous areas.Red clay slope in Hengshao expressway of Hunan was taken as the main research object,then the cause of red clay in this area was expounded,and the basic indoor geotechnique experiments were conducted,mainly including basic physic index experiments and basic dynamic index experiments.Finally,it came to the conclusion of the engineering characteristic of typical red clay.By practical investigation on the red clay slope,the features and reasons of the damage were analyzed and explained.The crevice equivalent model and the calculation model of rain infiltration were applied in a simulative way to analyze the crevice distributions and the infiltration laws in the crevice soil by choosing the crack rates of 0.15%,0.3% and 0.6% respectively and the crevice depths of 0.5m,0.75 m,1.0m,1.25 m and 1.5m.The method of Morgenster-Price was applied to study the stability of red clay slope under the condition of rain infiltration.The risk factors of investigation and identification were conducted on the red clay slope in Hengshao Expressway.Based on the characteristics of red clay slope,the evaluation index was put forward which was different from the general clay,then distinctive safety risk evaluation system of red clay slope was established.Rely on the practical engineering,the Fuzzy-AHP theory was introduced to compute the weight of various factors and membership vector related with risk grade,so slope stability grade was achieved.According to the results of risk evaluation,the key influencing factors were determined.Two technique solutions were proposed for the damage features and disability causes of red clay slope.The software of FLAC3 D was applied to the numerieal analysis for the K127+500 on the right side of red clay slope by two different treatment technologies.Calculation results showed that two kinds of treatment technologies both can satisfy the requirements of slope stability.Moreover,engineering cost,construction technique,coverage and environmental influence etc were analyzed,compared and selected.Eventually,the comprehensive treatment scheme reached that was brushing slope,anti-slide retaining wall,supporting sewer,planting grass with net and drainage.