The Derivation And Application Of The Theoretical Formula Of The Improved Method Of Foundation Pit Anti-Uplift Stability Analysis

On the basis of previous works,aiming at the shortcomings of the existing methods for analyzing the uplift stability of foundation pit,an improved method for analyzing the ultimate equilibrium stability of deep foundation pit against uplift is developed,the main research contents of this paper are as follows:(1)Paper introduces the methods of stability analysis of.foundation pit,and analyzes the disadvantages of each method in the calculation process.(2)The pit on the surface of the arc shape,the sliding soil is divided into active and passive earth pressure calculation,according to the corresponding region,the principle of limit equilibrium analysis model was constructed based on the stability of foundation pit,puts forward the improved method anti heave stability analysis of a two-dimensional pit.At the same time,the formation of pit slip surface,the arc length and the surface of the normal stress correction method modified analysis method of excavation against heave stability,and puts forward the method of anti heave stability analysis of a simple and reasonable multi stratum foundation pit.The example shows that the calculation results of this method are in agreement with those of other methods,and the influence of the ratio of the foundation pit and the physical and mechanical parameters of the rock and soil on the uplift safety factor of the foundation pit is studied.(3)Based on the analysis method of anti heave stability of two-dimensional foundation pit,the stability analysis model of anti heave stability of three-dimensional foundation pit is established.The potential sliding body of the foundation pit is approximately a cylindrical body,and the cylindrical body is composed of an arc sliding surface and a side face at both ends.Moreover,considering the spatial effect of the soil and the anti slip moment of the column body,a method for analyzing the stability of the uplift of the foundation pit is proposed.At the same time,the calculation length of the foundation pit and the influence of the depth of the retaining wall inserted into the soil on the stability coefficient of the heave resistance of the foundation pit are investigated.The example shows that the calculation results of this method are in agreement with those of other methods.(4)The method was applied in Wuhan Changting Street No.five-channel air defense project pit excavation engineering,analyzes the basal heave stability under different working conditions.The analysis results were consistent with the actual situation shows that this method has good practical engineering value.