Time Effect And Long-Term Stability Prediction Of Anti-Slide Pile Slope In Loess Area

Anti-slide pile is widely used in slope reinforcement engineering due to its strong skid-resisting capacity,simple structure and convenient construction.However,the engineering quality of anti-slip pile slope is constantly changed by the influence of long-term external environment(rainfall,temperature,weathering,etc.),which leads to various diseases and affects the engineering quality and long-term stability of anti-slip pile slope engineering.Therefore,the thesis focuses on the theme of long-term stability of anti-slip pile slopes in loess areas,and analyzes the time effect of anti-slip pile slopes in loess areas and its long-term stability prediction by case investigation,laboratory test,field monitoring,numerical simulation and theoretical analysis.The main contents and innovation results are as follows:(1)Based on case investigation,the applicability of anti-slip pile reinforced slopes in loess areas during service period is discussed,the damage types of anti-slip pile slopes are summarized,the damage modes are generalized,and the factors affecting their long-term stability are analyzed.The deformation and damage patterns of anti-slip pile slopes include four typical damage patterns:shearing or breaking,pushing and tipping,soil arch effect failure and over-topping.The physical and mechanical properties of soil,slope geometry,anti-slip pile structural parameters,service time and extreme rainfall weather determine the long-term stability of the slope.(2)The optimal creep parameter values of loess based on field monitoring and parameter inversion are constructed,and the decay evolution law of slope mass under the action of creep factors of anti-slip pile slope is revealed.Based on the field displacement monitoring data,the Singh-Mitchell model parameters were inverse-analyzed using the orthogonal design inverse analysis method to obtain the best parameter values of loess;the long-term stability of the anti-slip pile slope was obtained by substituting values into the creep coupled model fitting calculation.(3)Based on the characteristics of extreme rainfall in northern Shaanxi and the principle of numerical simulation analysis of rainfall infiltration process,combined with the suction and seepage characteristics of unsaturated loess,a numerical calculation model under the combined effect of creep and extreme rainfall was established to reveal the influence law of extreme rainfall on the long-term stability of slopes,and the time effect of long-term stability of anti-slip pile slopes in loess areas under extreme rainfall conditions was obtained.(4)Based on the strength reduction method,combined with gray theory and multiple nonlinear regression analysis theory,and with the help of ABAQUS numerical calculation software,the sensitivity of long-term stability coefficients to each influencing factor is obtained,and a prediction model of long-term stability of anti-slip pile slopes in loess areas is established and verified based on engineering examples.