Chance Constrained Programming Analysis Of Soil Slope Stability Based On Limit Equilibrium Method

The analysis of slope stability is an important subject in the field of geotechnical engineering.The common method of slope stability analysis is deterministic analysis method and uncertainty analysis method.The deterministic analysis method can not take into account the influence of the randomness of rock and soil parameters on the stability of soil slope in the analysis of slope stability.The reliability analysis method can make up the above shortcomings.However,the conventional reliability analysis method generally considers only the randomness of rock mass parameters and the shadow of the geometric condition randomness to the slope stability coefficient.In the judgement of failure of soil slope failure,the Moore Kulun criterion is adopted,and the constraint condition between various parameters of soil is considered according to the deterministic method.It should be noted that the parameters of rock and soil are random,and the constraint relation between them is not definite.Therefore,the chance constraint programming theory is introduced to analyze the slope stability to solve the above shortcomings.This paper mainly analyzes the stability of the soil slope,and the contents are as follows:(1)This paper uses the Fellenius method in the limit equilibrium method as the principle of slope stability analysis,uses the MATLAB software to write the corresponding calculation program,and uses the professional Slide program as the contrast tool to ensure the correctness of the matlab calculation program,and explores the influence of soil cohesive force,internal friction angle,slope rate and other factors on the stability of soil slope.The results show that,without considering the randomness of soil parameters,the arc surface corresponding to the minimum stability coefficient of the soil slope without anchor reinforcement usually appears at the foot of the slope.The anchor reinforcement will improve the stability coefficient of the soil slope,and make the circular arc surface corresponding to the minimum stability coefficient of the soil slope to occur.Under the same conditions,the greater the cohesion and internal friction angle,the greater the stability factor of the slope.(2)The genetic algorithm is applied to the stability analysis of monolayer slope,and2 conventional methods and chance constrained programming methods are adopted.The results show that the arc surface and the stability coefficient obtained by the three methods are almost the same for the single layer soil slope with a height of 10 m,and do not show much difference,Moreover,the stability coefficient and the arc surface obtained by chance constrained programming under different confidence levels are not much different.(3)The genetic algorithm is combined with the chance constrained programming theory to analyze the stability of single layer slope under prestressed anchor reinforcement conditions.The results show that the randomness of soil parameters has a significant effect on the stability of soil slope.After considering the randomness of the soil parameters,the results obtained by the 2 conventional methods and the chance constrained programming methods are different.The chance constrained programming method is less than the conventional method in calculating the range of slopes that meet the safety requirements.Moreover,the higher the confidence level of chance constrained programming,the smaller the range of soil slope that meets safety requirements.The theory of chance constrained programming shows that the stress at the bottom of the prestressed anchor bolt makes the stress at the bottom of the soil bar larger,the stability of the soil slope is worse,and the stability is worse after considering the randomness of the soil parameters.(4)The chance constrained programming method is applied to the stability analysis of three layers of soil slope.The results show that the randomness of soil parameters makes the range of soil slope smaller in accordance with the safety requirements.The arc surface obtained by the conventional method is different from the circular arc surface obtained by the conventional method.The conventional method considers that the slope is slipped at the foot of the slope while the soil slope is destroyed.The chance constrained programming method considers that the bottom of the slope can be the slip point of the slope failure along the slope.