嵌岩端承桩竖向承载的扩孔理论分析

探讨了嵌岩桩嵌岩段的应力路径及工作机理,应用圆孔扩张理论,分析了嵌岩桩的承载机理.随着桩周挤压应力p的增大,围绕柱形孔的柱形区域将由弹性状态进入塑性状态,塑性区随p的增大而不断扩大,塑性区以外土体将保持弹性状态.利用弹塑性理论和体积平衡原理,推导了嵌岩桩嵌岩段的极限强度以及嵌岩段的极限竖向承载力的计算公式,并将扩孔理论分析结果与实测试验资料进行分析对比,研究表明,该方法可以成为解决嵌岩桩实际工程问题的个性化工具.

Analysis of cavity expansion theory of end-bearing rock-socketed piles under vertical load

The stress path of rock-socketed pile and its work mechanism are discussed.Based on cavity expansion method,the load bearing mechanism of rock-socketed piles is analyzed with the increasing of stress p surrounding the pile,the column part surrounding columnar hole transfers from the elastic state into plastic state.With the stress p increasing,the plastic area exposed;and the part beyond plastic part still is in elastic state;by using elastoplastic theory and volume-balance equation,a calculating formula of ultimate bearing capacity of rock-socketed portion is derived.Then the results of cavity expansion theory analysis is compared with the experimental data.The research results show that this method can become the special implement to solve the engineering problem of rock-socketed piles.