Study On Critical Slip Surface Of Soil Slope Stability

The destruction of artificial or natural slope will have an important impact on construction engineering,economic activities and ecological environment,Therefore,it is an important research content to accurately determine the critical slip slope slope analysis.The existing soil slope stability analysis methods have some disadvantages,such as the numerical analysis method and determining the initial stress by plane,arc shape(plane,circular surface,log spiral surface,etc.),the optimization method is not accurate,but the result is local solution or nonconvergence with excessive degrees of freedom.Therefore,it is necessary to further analyze the stability problem of the slope.In view of the above problems,this paper makes a tentative improvement: based on the limit balance theory,the strip separation method and the search method are combined to fix the abscissa of each block by preset the shear exit position of the potential slip crack surface,reduce the degree of freedom,reduce the calculation amount,and the critical slip crack surface found is closer to the engineering reality.The main work and achievements of this paper are as follows:(1)Based on the limit equilibrium theory,the bar classification method is combined with the search method.By presetting the shear exit position of the potential sliding crack surface,taking the shear inlet abscissa and each block ordinate as the variables,taking the safety factor as the target function,the relationship expression between the target function and the variables is established,and the sliding crack surface and safety factor are solved by means of finding the stationary point and extreme value.Take different shear exit positions to obtain the corresponding safety factor.By fitting the function between the shear outlet position and its corresponding safety factor,the minimum safety factor,critical slip surface and shear exit and shear inlet position can be found.(2)The international classical slope examples are analyzed,and then the reliability is verified by comparing the minimum safety factor with the results of other different methods.And the critical slip crack surface is closer to the actual situation.And the critical slip crack surface is not the circular arc surface destroyed by the slope foot.(3)Under the method of this paper,the influence of the cohesive force,internal friction Angle,slope height,slope Angle and load on the critical slip crack surface and stability of the slope is analyzed.With the increase of the cohesion,the slip exit of the slope is gradually far away from the slope shoulder.With the increase of the internal friction Angle,the sliding crack develops towards the shallow slope,and the shear exit position is gradually close to the slope foot,and the shear inlet position is gradually close to the slope shoulder.With the increase of the slope height,the sliding crack extends to the interior of the slope,and the shear exit position of the sliding crack surface is gradually closer to the slope foot and the slope shoulder.With the increase of the slope ratio,the critical slip fracture surface of the slope is gradually steepened,the slip fracture surface extends inside the slope,and the shear exit position of the shear entrance surface is gradually far away from the slope shoulder.With the increase of the load of the slope top,the slip crack extends inside the slope,the shear exit gradually approaches the slope foot,and the shear entrance is gradually moved away from the slope shoulder.(4)The influence of the shear strength of the soil of the slope on the critical slip surface and stability of the slope shows that when the slope is located from the bottom of the slope surface,the depth of the slope deepens,and the slope stability is reduced.When the slope is located on the hard underlying layer,the shear exit of the sliding crack surface is near the foot of the slope,and the shear edge of the slip crack surface depth becomes shallow,the landslide volume is reduced,and the slope stability is improved.