嵌岩桩嵌岩段的岩石极限侧阻力系数

嵌岩桩在岩土工程中已得到广泛应用,但如何准确计算嵌岩段桩的极限侧阻力仍是工程设计人员面临的重要课题。收集整理了不同时期、不同地区、不同岩石强度和不同嵌岩条件下开展的145个嵌岩桩竖向下压承载力试验成果,主要包括嵌岩段岩石类型及其单轴抗压强度、嵌岩桩的直径与嵌岩深度、嵌岩段桩的极限侧阻力等。定义嵌岩段桩的极限侧阻力和岩石单轴抗压强度的比值为嵌岩桩嵌岩段岩石极限侧阻力系数,分析了桩径、嵌岩深度、嵌岩深径比和岩石强度对嵌岩段极限侧阻力和岩石极限侧阻力系数的影响规律,建立了嵌岩段岩石极限侧阻力系数与岩石单轴抗压强度之间的拟合关系式,给出了不同可靠度水平下岩石侧极限阻力系数取值。

Analysis on ultimate side shear resistance factor of piles socketed into rocks

Rock-socket pile foundations have been widely used in engineering practices. It is important to determine the ultimate side shear resistance of the piles socketed into rock for designers. In this study, the results of 145 compression load tests were collected to examine several issues related to the bearing capacity behavior of rock-socket piles. All these load test results were representative since they were carried out worldwide, on different rock types and rock-socket conditions, for a long time period. Using these available load test case history data, the socketed rock type of piles, diameter and embedment depth of socketed piles, uniaxial compressive strength of rock in nature, and the ultimate bearing side resistances were collected. The ratio of ultimate side shear resistance to unconfined compressive strength of the rock was denoted as the ultimate side shear resistance factor of the piles socketed into rocks. Effects of pile diameter, rocked depth, ratio of rock rocketed depth to diameter, and the unconfined compressive strength of the rock on ultimate side shear resistance and the influential factors were evaluated. Empirical relationships between the ultimate side shear resistance factor and the unconfined compressive strength are suggested, and based on the statistical results, the specific design recommendations for the ultimate side shear resistance factor are provided.