Study On Stress And Deformation Characteristics Of Balance Weight Retaining Wall Under Special Terrain Conditions

The balance weight retaining wall has good structural self stability,and reduces the advantages of excavation and backfill.It has been applied in mountainous area highway reconstruction and expansion projects which are restricted by terrain.The traditional design method is not reasonable enough to calculate the earth pressure of the retaining wall under the special terrain conditions such as the foundation is a suspended rock mass,the mechanism of structural plane,retaining wall and hanging rock relative position and vehicle load effect on the wall is not clear,easy to cause the wall failure and instability,affecting traffic safety.In this paper,combined with the G307 renovation and expansion project,the theoretical analysis,field test and numerical simulation analysis are used to systematically study the stress and deformation characteristics of the special terrain balance weight retaining wall.The main research results are as follows:1.Based on Coulomb's earth pressure theory and existing research results,the relationship between the earth pressure intensity at one point of the wall and the displacement of this point was established,according to the failure mechanism of the combined displacement model,the combined displacement model is considered as the two basic displacement modes in a certain way,as a result of the superposition,a formula for calculating the active earth pressure of the non-limit state cohesive soil is proposed.Comparing with the field test data,it shows that the result calculated by this formula is more in line with the actual situation.Because the theory of earth pressure in non-limit state is not yet mature,it is an exploratory attempt to apply it to the calculation of earth pressure in gravity retaining wall,and more experiments are needed to verify it.2.During the construction process,the retaining wall rotates and moves around the bottom of the wall(RBT displacement mode).Along the depth direction,the soil pressure in the upper and lower walls increases first and then decreases,which is quite different from the linear distribution law of the Coulomb earth pressure.There is a certain range of tensile stress on the top of the wall;under the influence of the lifting action of the counterweight,the earth pressure of the lower wall is smaller than the theoretical calculation.There is a certain irrationality in designing the retaining wall using traditional theory.3.The finite element software was used to analyze the stress and deformation characteristics of the balance weight retaining wall,and the stress and strain states,the distribution law of the earth pressure behind the wall,and the law of the wall body displacement were obtained.The force and deformation characteristics of the retaining wall are analyzed under the condition of the retaining wall position,the support condition of the lower part and the change of the driving load position.The results show that the construction of the lower support can obviously improve the stress and deformation characteristics of the retaining wall;The change of the distance from the wall toe to the suspended rock mass influences the stability of the retaining wall significantly;Single-vehicle strength changes have little effect on the overturning stability of the retaining wall,near-wall car is one of the main factors affecting the horizontal displacement of the wall.