Abstract: This study focuses on large diameter deep embedded rock piles of a rail-cum-road Yangtze River bridge under overload conditions. Traditional research approaches regarding the lateral friction resistance of rock-embedded piles assume that the pile-rock interface is a plane. However, it is proposed that in deep embedded rock foundations in thick rock strata, the pile-rock interface actually forms a rough surface with significant geometric variations. Therefore, it is necessary to consider the joint roughness coefficient (JRC) and the pressure exerted by the initial setting of the concrete against the surrounding rock (referred to as $ P_{hi} $) to evaluate the bearing capacity of the cast-in-place pile. By conducting indoor direct shear tests on concrete-rock interface samples, parameters for the pile-rock interface considering JRC $ ^{3D} $ and $ P_{hi} $ are obtained, and a numerical calculation model for the vertical load of rock-embedded piles is developed to analyze the lateral resistance at the pile-rock interface, as well as the load transfer mechanism and ultimate bearing capacity of the pile foundation under overload conditions. The following conclusions are drawn: when subjected to upper load conditions, the lateral resistance of the rock-embedded segment of large diameter deep embedded rock piles varies with depth, which differs from the assumption in pile design codes that the lateral friction resistance remains constant across the same stratum; during the formation of the pile-rock interface, the self-weight stress of the concrete slurry increases with the depth of the pile, significantly enhancing the depth effect of the interface. characteristics and, consequently, improving the allowable bearing capacity of the pile foundation. A modified formula for the mobilization coefficient of the lateral resistance, taking into account the squeezing effect of the pile foundation and the depth effect of the interface characteristics, is proposed. The research results may provide reference for the design of the large diameter deep embedded rock piles in complex strata under overload conditions. characteristics and, consequently, improving the allowable bearing capacity of the pile foundation. A modified formula for the mobilization coefficient of the lateral resistance, taking into account the squeezing effect of the pile foundation and the depth effect of the interface characteristics, is proposed. The research results may provide reference for the design of the large diameter deep embedded rock piles in complex strata under overload conditions.
Keywords: deep embedded rock piles; pile-rock interface; roughness; bearing characteristics; lateral resistance of pile body
合肥工业大学学报自科版