考虑挤密效应的基桩承载力可靠性分析

基于桩的挤密效应,分析黄土地区基桩的竖向受力情况,并利用一次二阶矩法推导出基桩竖向承载力的可靠度计算公式.借鉴国内外有关规范和文献中给出的目标可靠度指标,建议将3.5作为黄土地区基桩竖向承载力的评价标准,并在此基础上推导出有效桩径的计算公式.在有效桩径确定的基础上,推导出桩间距计算公式.最后通过工程实例计算出基于可靠行设计的有效桩径和桩间距.可靠性理论引入桩基的设计中有效地克服了传统定值设计方法的不足,具有重要的工程实际意义.

Reliability analysis of bearing capacity of ground piles with pressing effect

Based on pressing effect of pile,the vertical bearing capacity of ground pile in loess zone was analyzed and its computation formula was derived by using the first degree second order moment method.The target reliability index stipulated in related standards and literatures at home and abroad was used for reference and it was suggested that 3.5 was to be taken as the criterion for evaluating the vertical bearing capacity of the ground pile in loess zone.On this basis,the computation formula of effective pile diameter was derived and then the pile spacing was also derived according to the effective pile diameter.Finally,an actual engineering case was taken as an example to calculate the effective pile diameter and pile spacing on the basis of reliability design.The introduction of reliability theory into pile ground design overcame effectively the defects in traditional constant-value design method and had important significance for engineering practical.