Study On Calculation Method Of Double-row Anti-slide Piles

As an effective engineering mean to mitigate the landslide disasters,anti-slide pile has been widely used in practical engineering.In the design of double-row piles,how to determine the magnitude and distribution of the landslide thrusts on the front and back of the piles is the key to the design.However,there is no better calculation method at present.By analyzing the forces on the anti-slide pile and the sliding body between the front and back row,it can be found that the displacement of the anti-slide pile should be equal to the displacement of the sliding body between the piles.Therefore,it is necessary to research the methods to compute the horizontal displacement of anti-slide piles and the displacement of sliding body.The main contents of this paper and the results are as follows:(1)An improved method is developed,in which m-method model is employed to represent the interaction between landslide body and pile.The equations for the part of pile above and under slip surface are constructed respectively,and the expressions of displacements and internal forces are solved with power series method.The bending moment and shear force at slip surface can be obtained by using the consistent conditions of deflection and slope of the pile,and then the deformations,internal forces of the pile and the interaction between pile and landslide body can be computed readily.(2)By assuming the stress distribution of the sliding body in the landslide,the calculation method of the stress field of the sliding body was derived by using the Airy stress function method in elastic mechanics.The formulas of the displacement field of the sliding body were obtained by the geometric equation and generalized Hooke’s law in elastic mechanics.It establishes the foundation for solving the anti-slide pile’s thrust by using the deformation coordination relationship of anti-slide pile and the sliding body between the piles in front row and back row.(3)A concept of "sharing ratio"(the ratio of the force of anti-slide pile to total sliding force)was developed,and the displacement of the soil and the back pile can be calculated by the method proposed in the previous paragraph.By using the deform coordination relationship of anti-slide pile and the sliding between the front and back piles,a method was established to compute the "sharing ratio".Moreover,the thrust on the back row pile can be solved.Then the deformation and internal forces of front pile and back pile can be calculated easily.(4)Applying the method to an engineering example,good results were obtained,which verified the feasibility of the proposed method.