重庆市嵌岩桩单桩承载力可靠指标分析

Research on Index of Reliability for Bearing Capacity of Rock-Socketed Single Pile in Chongqing

对重庆市近10年102根嵌岩灌注桩试桩资料进行统计分析,建立单桩无量纲随机变量的极限状态方程,采用改进JC法和Monte-Carlo法计算得到重庆地区嵌岩桩基目标可靠度的范围,进而提出重庆地区嵌岩桩基目标可靠指标的建议值。最后引入可靠系数(代替荷载分项系数和抗力分项系数)并计算了嵌岩桩单桩承载力的可靠系数,提出采用可靠系数表达的极限状态设计实用表达式,该表达式体现了简单实用的原则,利于设计人员掌握和理解,便于工程应用。

Based on the data from in -situ 102 rock -socketed test piles in Chongqing in recent 10 years and utilizing the limit state equation of the dimensionless random variables, the reliability analysis of the bearing capacity of rock - socketed single pile is made and the scope of the target reliability of rock - socketed piles in Chongqing is calculated with both JC method and Monte - Carlo method respectively. Furthermore, the target index of reliability is suggested. Finally, the concept of reliability coefficient （to replace the load partial factor and the resistance partial factor） is given and the bearing capacity of the single pile is determined by utilizing optimization method. Besides, the practical limit state design equation using reliability coefficient is put forward for its advantage of incarnating the simple and practical principle and being easy mastered and understood by the designers.