A numerical simulation study was carried out on the response of a multi-row micro-pile group subjected to soil lateral displacement.The plastic deformation characteristics of micro-pile was considered in the numerical model,and the pile parameters were obtained by performing a refined finite element model against some published pile bending tests.Based on the analysis of the micro anti-slide pile response,a simplified formula for calculating the ultimate anti-sliding force was deduced.The influence of the row spacing and the friction coefficient of slip surface were studied.The results show that in the multi-row case,the pile-soil interaction is mobilized in a larger depth range than the case of a single row of piles,and the overall stiffness of structure is higher.However,the pile group effect reduces the pile-soil interaction force.As a result,the anti-sliding force of a single pile in the multi-row structure is only 50％-70％of that of the case of a single-row.The influence of the slip surface friction coefficient is greater on multi-row piles than on single-row piles.Increasing friction coefficient significantly reduces the pile-soil interaction force and increases the pile influencing depth range,which result in the reduction of anti-sliding force of pile.Increasing the row spacing can improve the overall resistance of the multi-row micro-pile structure.When the row spacing is less than 7 times of pile diameter,increasing the row spacing mainly reduces the pile influencing depth range.While the sliding resistance is mainly increased by the variation of the pile-soil interaction force distribution when the row spacing is greater than 7 times of pile diameter.The proposed calculation formula of the bearing capacity of anti-sliding pile can well reflect the force characteristics of the micro-pile,which is worth to be further researched and promoted.
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