Stability Analysis Of Slopes Considering The Time And Depth Effect Of Strength Parameters

Slope stability analysis is an important topic that involves hydropower, transport, industrial and civil constructions, mining and other fields. Traditional slope safety evaluations models based on limit equilibrium theory usually do not considering time and space effects of strength parameters. It assumed that the mechanical strength of the same soil horizon is a certain value. The simplification of the calculation model may be make the calculation results much differ from the truth. For this cause, the article considering the mechanical strength parameters (such as the cohesion c, friction angleφ, shear strengthτ, etc.) gradually change over time and depth, and make use of the limit equilibrium theory to calculate the slope safety factor, at the same time, introduce the random search algorithm to search for the most dangerous sliding surface and the corresponding minimum safety factor of slope. With modes of the weathered soft rock slope, the reinforced and non-reinforced embankment on soft soil foundation were established and discussed, the article achieved the following major research results and conclusions.(1) Regression analysis of the depth effect of strength of each layer soil was studied based on the investigation data of weathered soft rock and residual soil slopes in Changsha. Time effect model of strength parameter was established according to the domestic literature data. On that basis, slope stability analyzing model which considering time and depth effect of strength parameters is conducted, and the relevant calculation program is compiled. It has great difference between the results whether consider the time and depth effect of strength parameters or not. It will be more correspond to the true situation when considered.(2) Considering the depth effect of the shear strength and consolidation degree, the stability analysis model of embankment slope on soft soil foundation is established and the relevant calculation program was compiled. The calculation results show that it has great difference between the minimum safety factor and the corresponding critical sliding surface of embankment slope with loading, whether consider the time and depth effect of strength parameter or the depth effect of consolidation degree or not.(3) Considering the influence of additional stress Caused by level friction resistance of reinforced embankment, depth effect of strength parameters, and depth effect of consolidation degree, the stability analysis model of reinforced embankment based on soft soil foundation is established and the relevant calculation program is compiled. Results show that it has great influence on the stability analysis results when considering the depth effect of strength parameters, depth effect of consolidation degree, and the force caused by reinforce.