复合桩基的承载力安全度与可靠度分析

Safety and reliability of composite pile foundation designed by controlling settlement and bearing capacity

本文分析了沉降控制复合桩基的承载特点和设计方法,针对目前工程界普遍关心的设计条件下的整体安全度与承载能力可靠度的计算问题进行了研究。在提出沉降控制复合桩基安全度计算方法的基础上,运用可靠度理论建立了相应的可靠性指标计算方法。结合工程实例,对现行沉降控制复合桩基设计方法的安全度进行了校核,对各随机变量在复合桩基可靠度计算中的敏感性进行了分析,明确了各随机变量变异性对可靠性指标的影响程度。同时,对设计容许沉降量、安全系数和可靠性指标之间的关系进行了探讨,取得了一些规律性的结果。为进一步建立基于概率极限状态的可靠性设计方法打下了基础,对实际工程中的复合桩基设计也有一定的指导意义。

In this paper, the bearing character and design method of composite pile foundation designed by controlling settlement and bearing capacity are analyzed. The issue, which is widely concerned today by the engineering circles, of calculating its integral safety and index of reliability about bearing capacity is also researched. The method for calculating safety coefficient is brought forward and then the method for calculating the index of reliability is established by using reliability theory. By use of these methods,the safety of this kind of composite pile foundation is checked by means of an engineering project with the sensitivity of parameters analyzed. Thus the degree of effect of stochastic variables on reliability index are clarified. Further discussion is made on the relationship between allowable settlement and reliability index or safety coefficient. The results acquired in this paper lay a foundation of building the reliability design method and have meaning for designing composite pile foundation in practice.