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根据滑移剪胀机理,建立了滑动剪胀阶段和剪切滑移阶段侧摩阻力的表达式,求得了滑动剪胀阶段的嵌岩段摩阻力及桩身轴力的解析式。基于所获得的解答,分析了嵌岩段摩阻力及轴力随深度变化的分布规律,并对桩端荷载分担比进行了研究。研究表明:嵌岩比l/d与综合影响系数λ对桩端荷载分担比P_b/P_d影响较大,在不同的λ下,随着嵌岩比l/d的增加,桩端荷载分担比P_b/P_d均不同程度地减小,随着l/d增大到一定值时,P_b/P_d接近于0;现场大直径嵌岩桩静载试验结果表明,正常工作状态下嵌岩桩具有摩擦桩的性质,桩侧土阻力和嵌岩段摩阻力分担荷载的比例较高,桩端阻力所占比例不大,在全加载过程中变化也不显著。最后结合理论公式反算得到计算参数,理论计算结果与实测数据吻合良好。
According to the slip dilatancy mechanism, the expressions of the lateral frictional resistance at the sliding dilatancy stage and the shear-slip stage are established, and the analytical expressions of frictional resistance and axial force of the rock-slipping in the sliding dilatancy stage are obtained. Based on the obtained solutions, the distribution of frictional resistance and axial force with depth of rock-socketed sections is analyzed, and the load-sharing ratio of pile heads is studied. The results show that the ratio of loading rock to l / d and the combined influence coefficient λ have a great influence on the load sharing ratio of pile tip P_b / P_d. Under different λ, with the increase of rock-in-rock ratio l / d, / P_d decreases to some extent. As the value of l / d increases to a certain value, P_b / P_d approaches zero. The static load test results of on-site large-diameter rock-socketed piles show that in normal working condition, , The ratio of soil resistance on the side of pile and frictional resistance of rock-socketed section is relatively high, and the proportion of pile-end resistance is not large, and the change is not significant during the whole loading process. In the end, the calculation parameters are obtained by backcalculating the theoretical formula, and the theoretical calculation results are in good agreement with the measured data.