Analysis of forced deformation of double row support piles considering pile interaction

Calculation of deformation and internal force is one of the important contents of the double-row pile retaining structure. The double-row support pile structure is a space gantry structure composed of front row piles, rear row piles and pile top tie beams. When subjected to horizontal loads, flexural deflection to the pit occurs in the rear pile and the soil between the piles is squeezed. At the same time, the soil between the piles generates thrust to the front pile, so that flexural deflection to the pit also occurs in the front pile. The soil before the front piles is extruded, when the supporting structure transmits horizontal loads, there is a very complicated interaction between the front and rear piles and the soil between the piles. Based on the above-mentioned forced deformation characteristics of double-row pile retaining structure, the front and rear piles are regarded as vertical elastic foundation beams. The interaction of front and rear piles is considered by using the Euler-Bernoulli double-layer beam theory. The soil interaction between the piles is simulated through the horizontal spring, and the active earth pressure acting on the rear piles is calculated by the Rankine soil pressure. The passive earth pressure acting on the front pile below the bottom surface of foundation pit is calculated by using the elastic resistance method. From the bottom of the foundation pit, the double-row piles can be divided into upper and lower parts, the differential equations of the deflection deformation of the front and rear piles for each element are established by the force balance of the piles. The pile end constraints and the continuous conditions at the bottom of the foundation pit are introduced to obtain the analytical solution of the equation. A calculation method for the double-row pile retaining structure considering the pile interaction and the interaction between pile and soil is given in this study. By combining two examples, the calculation results of this method are compared with the reported results to verify the feasibility of the proposed method. This method may provide reference for the design of double-row pile retaining structure in practice engineering.