Estimation of the lateral earth pressure acting on a row of piles given the soil arching effect

Abstract The plastic deformation in the ground between piles undergoing lateral soil flow starts first from the crown part of the external arch in the soil arching zone; then, the plastic deformation is developed to the wedge part around the piles. The geometric configuration of the soil arching zone between the piles is newly defined through the analysis of the model test result. Based on the geometric configuration of the soil arching zone, a new theoretical equation is proposed using the theory of cylindrical cavity expansion. To verify the new equation, a field monitoring test is performed at a cut slope that is reinforced by stabilizing piles, and the test results and the equation are analyzed and compared with the equation proposed by Ito and Matsui (1975). It is noted that the new equation can better capture the measured deflection from the tests than the model by Ito and Matsui (1975). Therefore, the new equation can be adapted to estimate the lateral earth pressure acting on a pile and a row of stabilizing piles can be eventually designed without overestimating the lateral earth pressure.