(1. 中南大学 资源与工程安全学院，长沙 410083；
2. 成都理工大学 地质灾害防治和地质环境保护国家重点实验室，成都 610059；
3. 湖南省交通规划勘察设计院，长沙 410008；
4. 解放军理工大学 国防工程学院，南京 210007)
摘 要: 利用响应面方法开展横向荷载下斜坡桩的可靠性研究。引入一种考虑斜坡效应的新型载荷-位移(p-y)曲线方法模拟斜坡上横向受荷桩桩-土作用系统，采用斜坡桩桩顶位移和桩身弯矩作为功能准则，建立桩顶位移失效和桩身最大弯矩两种失效模式下横向荷载作用斜坡桩基的可靠性分析方法，利用蒙特卡罗法验证了斜坡地面上横向受荷桩的可靠性分析方法。讨论横向荷载作用下斜坡桩基可靠性的影响因素。结果表明，桩顶位移的变异性随着极限承载因数(Npu)、50%水平的弹性模量(E50)和水平荷载(H)变异系数的增加而增加，Npu和无量纲系数(λ)的负相关关系使桩顶位移概率密度函数(PDF)值的分散性降低；相反，Npu和λ的正相关关系使桩顶位移的PDF值产生较大变化。对于地面水平极限承载因数(Npo)和λ，Npo和λ之间的正相关关系和负相关关系均使桩头位移的PDF值产生较大变化，并且Npo和λ之间的负相关关系会明显增加这种变异的响应。
关键字: 侧向受荷桩；响应面法；概率；可靠性分析
（1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China;
2. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,
Chengdu University of Technology, Chengdu 610059, China;
3. Huan Provincial Communications Planning Survey & Design Institute, Changsha 410008, China;
4. College of Defence Engineering, PLA University of Science and Technology, Nanjing 210007, China）
Abstract:Response surface method is used to study the reliability analysis of laterally loaded piles in sloping ground. A development load-displacement (p-y) curve for laterally loaded pile response in sloping ground is used to model the pile-soil system, both the pile head displacement and the maximum bending moment of the piles are used as the performance criteria in this study. The reliability analysis method of the laterally loaded pile in sloping ground under the pile head displacement and the maximum bending moment failure modes is proposed, which is in good agreement with the Monte Carlo method. The influences on the probability index of failure by a number of parameters are discussed. It is shown that the variability of pile head displacement increases with the increase in the coefficients of variation of ultimate bearing capacity factor (Npu), secant elastic modulus at 50% (E50) and level load (H). A negative correlation between Npu and non-dimensional factor (λ) leads to less spread out probability density function (PDF) of the pile head displacement; in contrast, a positive correlation between Npu and λ gives a great variation in the PDF of pile head displacement. As for bearing capacity factor on ground surface (Npo) and λ, both negative and positive correlations between them give a great variation in the PDF of pile head displacement, and a negative correlation will obviously increase the variability of the response.
Key words: laterally loaded pile; response surface method; probability; reliability analysis
