Study On Limit State Design Method Of Reinforced Soil Slope Based On Reliability Theory

The application fields of reinforced soil technology are expanding in China,including highways,railroads,urban infrastructure and other fields,and the applications involve a variety of structures such as roadbeds,retaining walls and slopes.Reinforced soil slopes not only have strong seismic resistance,good stability and convenient construction,but also have the characteristics of sustainability and low maintenance cost.At present,the design of reinforced soil slope in China mainly adopts the allowable stress method,and this method can no longer meet the needs of design,this thesis adopts the limit state design method based on reliability theory for the feasibility study of reinforced soil slope,the limit state design method is based on the failure limit state when the structure loses its proper function,through comprehensive consideration of various factors that may affect the safety of the structure,and the use of probability statistical methods The analysis and evaluation are carried out to ensure that the structure will not be damaged or fail during its service life.The main work of the thesis is as follows:(1)The variables affecting the stability of reinforced soil slopes are compiled and summarized by reviewing relevant literature,and the limit state equations for reinforced soil slopes under general conditions,seismic loads,and track and train loads are established based on the Swedish circular arc bar division theory.(2)Based on the established limit state equations for reinforced soil slopes,the target reliability indexes of reinforced soil slopes under general conditions,seismic loads,and track and train loads are calculated by the quantile method.The target reliability index increases with the increase of the height and seismic intensity of the reinforced soil slope,and the growth rate decreases gradually.(3)The sensitivity analysis of soil property parameters of reinforced soil slopes shows that the reliability index decreases with the increase of the coefficient of variation.The variability of soil shear strength index cohesion has the greatest influence on the reliability index of slope,followed by the influence of internal friction angle and the least influence of capacitance.(4)The coefficients were added to the established limit state design equations for reinforced soil slopes,and the subcoefficients of resistance and load for different grades of reinforced soil slopes under general conditions,seismic loads,and track and train loads were calculated using the quantile value method.And the calculation results are calibrated,and it is concluded that the reinforced soil slopes meet the requirements and the selected values of the subfactors are reasonable.(5)The analysis was carried out with the help of finite element simulation and analysis software PLAXIS 2D to analyze the overall stability of reinforced soil slopes under general conditions at different heights,cohesion and internal friction angles.The calibration values calculated based on the reliability theory are compared with those calculated based on the reliability theory,and it is verified that the limit state design method based on the reliability theory is feasible for the design of reinforced soil slopes.