Application Of Double Strength Coefficient Reduction Method In Slope Stability Analysis And Method Research

The problem of slope stability is a very important topic in geotechnical engineering.At present,there are many slope stability methods,mainly including limit equilibrium method and strength reduction method.The strength reduction method also includes the traditional strength reduction method and double strength coefficient reduction method.When analyzing the stability of slope,the strength reduction method can reflect the deterioration law of soil strength parameters which is more in line with the actual situation;The traditional strength reduction method reduces the shear strength parameters(c andφ)in the same proportion.However,a large number of scholars have proved that the deterioration laws of shear strength parameters(c andφ)in the process of slope instability are different,so it is more reasonable to use different reduction coefficients,that is,the double strength coefficient reduction method is more appropriate.Based on the double strength coefficient reduction method,this paper analyzes the slope stability,and mainly does the following work:(1)Based on the double strength reduction factor method,a new expression of comprehensive safety factor is proposed for slope stability,Several typical slope models are used for simulation,and the rationality and accuracy of the expression are verified by comparing with several existing definition expressions.(2)The realization process of the dual strength coefficient reduction method in the finite element software ABAQUS is briefly described,and three slope instability criteria that have been widely used at present are introduced,namely,the calculation non convergence criterion,the characteristic point displacement catastrophe criterion and the plastic zone breakthrough criterion.A typical homogeneous slope example is selected for simulation calculation and analysis,and the safety factors calculated by these three instability criteria are compared with Spencer method in the limit equilibrium method.It is found that the relative error between the first instability criterion and Spencer method is large,which overestimates the safety reserve capacity of the slope and is not suitable for slope instability criteria,The relative error between the latter two instability criteria and the results calculated by Spencer method is small,so it is recommended to select the latter two instability criteria as the evaluation criteria of slope stability.(3)The strength double reduction coefficient method is applied to the stability analysis of two types of more complex slope models.By comparing the safety factor calculated by the double emphasis reduction coefficient method with the Spencer method,M-P method,Bishop method,which are commonly used limit equilibrium methods,and the traditional strength reduction method,it is found that the results have good consistency,It shows that the strength double reduction factor method and the newly defined safety factor expression have good applicability and accuracy in the analysis of complex slopes;The influences of elastic modulus,Poisson’s ratio,dilatancy angle,cohesion,internal friction angle and grid element size on the calculation results of slope safety factor are discussed.(4)Two kinds of slope models are established.The first is the model with only groundwater,and the second is the combination model with rainfall infiltration in addition to groundwater.The stress,displacement and safety factor of the slope under the two conditions are compared and analyzed.The results show that the safety factor of the slope under the second condition decreases by 4.3% year on year,indicating that rainfall infiltration has a great impact on the stability of the slope;At the same time,the influence of rainfall time,rainfall intensity and saturated permeability coefficient on slope stability is analyzed.Figure [60] Table [16] Reference [61]...