基桩检测合格率的概率分析及可靠度评估  

Probabilistic analysis and reliability assessment for acceptance rate of foundation pile testing

作　　者：郑俊杰[1] 刘勇[2] 郭嘉[1] 徐志军[1] 

机构地区：[1]华中科技大学岩土与地下工程研究所,湖北武汉430074 [2]新加坡国立大学土木系,新加坡119260

出　　处：《岩土工程学报》2009年第11期1660-1664,共5页Chinese Journal of Geotechnical Engineering

基　　金：湖北省自然科学基金项目(2005ABA303)

摘　　要：基于概率论,分析了当前桩基工程质量评估的有关规范中存在的问题,建议采用检测合格率作为基桩质量的评估指标,并提出了评估基桩质量的可靠度方法。提出基桩检测合格率的先验分布服从标准Beta分布,并应用Bayesian方法求出该合格率后验分布的概率密度函数,结果表明后验分布也服从标准Beta分布。Bayesian方法的引入,摒弃了传统评估方法中仅根据一次检测结果来确定工程质量的缺点,并充分考虑了已有类似工程中的数据,使合格率后验分布的确定既具有概率统计理论基础,又具有工程实际意义。根据国内外相关规范和文献资料,选取目标可靠度指标3.2作为评估基桩质量的标准。可靠度方法的引入不仅使得桩基工程质量评估更加科学合理,而且可为相关规范的修订提供参考。With the aim to overcome some shortcomings in current specifications and codes concerning foundation pile testing, a reliability approach is proposed to evaluate the quality of pile foundations by taking the acceptance rate of foundation piles as a quality index. The prior distribution of this acceptance rate is assumed to follow a Beta distribution and the probability density function of the corresponding posterior distribution, which also follows a Beta distribution, and the acceptance rate is derived by employing the Bayesian approach. The use of the Bayesian approach solves the problem that the quality of pile foundations is evaluated by test results at one time, fully incorporates the existing in-situ data and enables the posterior distribution of acceptance rate not only with solid probabilistic basis but also practical senses. Based on worldwide specifications, codes and papers, a target reliability index of 3.2 is proposed as the criterion for evaluating the quality of pile foundations. The reliability approach conducts quality assessment in a quantitative manner and can be used as a reference for further revisions of relevant standards.

关 键 词：基桩检测 可靠度分析 合格率 Bayesian方法 

分 类 号：TU473[建筑科学—结构工程]