Time-dependent Deformation Characteristics And Evolution Of Weak Layers In The North Gang Slope Of The Fushun West Open Pit

The problem of high and steep slope stability has always been a key difficulty in geotechnical engineering.Under the influence of excavation disturbance and groundwater intrusion,the slope stability of the north gang slope of Fushun West Open Pit is weakened continuously,and the process of deformation and damage of high slope is often a complex geological evolution process,which is the process of accumulation of deformation from quantitative change to qualitative change,with strong time-dependent characteristics.To address the above problems,this paper focuses on the mechanism of time-dependent deformation and evolution law of the north gang slope of Fushun West Open Pit Mine,and clarifies the geological characteristics of the mine area by analyzing the engineering geology,hydrogeology and fault distribution conditions of the north gang.A numerical model reflecting the nonlinear creep characteristics in the accelerated creep stage was established,and the long-term rheological and mechanical characteristics of the north gang slope of Fushun West Open Pit were simulated and predicted,and the deformation characteristics and evolution law of the north gang slope were analyzed.The research results obtained are as follows:(1)By describing the engineering geology,hydrogeology and fault distribution of the north gang slope of Fushun West Open Pit Mine,the geological characteristics of the north gang slope of the mine area were analyzed,the mechanism of large deformation of the north gang slope and frequent geological hazards were summarized,and geological radar was used to monitor the north gang slope.(2)The mechanical properties of the mudstone specimens before and after the peak at different envelope pressures were studied through indoor tests,and the post-peak strain softening law of the mudstone specimens was revealed;conventional uniaxial creep and triaxial creep tests were conducted to analyze the mudstone creep damage characteristics and obtain the deformation law and damage characteristics of the mudstone specimens,compare the effects of different envelope pressures on the mudstone creep characteristics,and obtain the rheological mechanical properties of the North Gang mudstone.The rheological and mechanical properties of the North Gang mudstone were obtained.(3)Based on the Burgers model,the strain-softening nonlinear plastic element based on the Moore Coulomb was introduced,and a numerical model reflecting the nonlinear creep characteristics in the accelerated creep stage was established,and the parameters of the Burgers model were identified by the least squares method;and the rationality of the numerical model was proved by numerical verification,and the nonlinear mudstone creep damage model was compiled by compiling the dll file through the built-in Visual C++ port of UDEC to The results show that the obtained nonlinear mudstone creep damage model can better reflect the nonlinear damage characteristics of the mudstone creep damage process.(4)Using the numerical simulation method,a discrete element fracture grid model of the north gang slope was established,and the characteristics of the slope unloading stress field were analyzed by combining the field exploration and numerical verification method to realize the numerical simulation of the unloading zone by numerical simulation.The UDEC is used to simulate and reproduce the slope deformation and damage process to verify the three-stage damage theory;the deformation characteristics and evolution law of slope at different stages are analyzed,so as to evaluate and predict the slope stability and its disaster development trend.The paper has 51 figures,9 tables and 87 references.