考虑斜坡桩周土体空间变异性的基桩水平承载可靠性分析  

Reliability Analysis of Horizontal Bearing Capacity of Foundation Piles Considering Spatial Variability of Soil Around Slop Piles

作　　者：刘韬 段卫党 尹平保 王杰 LIU Tao;DUAN Weidang;YIN Pingbao;WANG Jie(Jiangxi Communication Investment Group Co.,Ltd.,Nanchang,Jiangxi 330108,China;School of Civil Engineering,Changsha University of Science&Technology,Changsha,Hunan 410114,China)

机构地区：[1]江西省交通投资集团有限责任公司,江西南昌330108 [2]长沙理工大学土木工程学院,湖南长沙410114

出　　处：《公路工程》2025年第1期32-40,共9页Highway Engineering

基　　金：江西省交通运输厅科技项目(2021H0005);国家自然科学基金资助项目(52178311)。

摘　　要：斜坡基桩的桩周土体空间变异性非常显著,为分析其对基桩水平承载特性及可靠性的影响,首先基于随机场理论,建立了考虑土性参数空间变异性的桩周土随机场模型;其次,将土性参数随机场模型引入p-y曲线,推导了水平荷载下斜坡基桩内力与位移分析的理论解答;最后,以某实际工程为例,探讨了随机场模型的变异系数、自相关性和稳定性对基桩水平承载可靠性的影响。研究表明:黏聚力随机场对基桩水平承载失效概率的影响比内摩擦角随机场大;与桩身材料屈服失效模式相比,土性参数空间变异性对水平位移失效模式下基桩可靠性的影响更为显著。当变异系数从0.1增大到1.0时,黏聚力随机场、内摩擦角随机场和组合随机场对应的基桩失效概率分别增大了20.7%、9.3%和26.2%;对于不同的自相关函数,其对应的失效概率计算值从小到大依次为正态分布型、指数型、指数余弦型、三角型和二阶自回归型;基桩水平承载失效概率随相关系数ρ_(c)、φ的增大而增大,而随随机场稳定性的减弱逐渐减小。The soil around the slope foundation piles shows obvious spatial variability.In order to analyze its influence on the horizontal bearing characteristics and reliability of the foundation piles.Firstly,based on the random field theory,a random field model of soil around pile considering the spatial variability of soil parameters is established.Secondly,the random field model of soil parameters was introduced into the p-y curve,and the theoretical solution for the analysis of internal forces and displacements of slope foundation piles under horizontal loads was derived.Finally,the influence of the variation coefficient,autocorrelation function and stability of the random field model on the reliability of the horizontal bearing capacity of the foundation pile is discussed in combination with the engineering example.The results show that the influence of cohesion random field on the horizontal bearing reliability of foundation piles is greater than that of internal friction angle random field.Compared with the yield failure mode of pile material,the spatial variability of soil parameters has a more significant influence on the reliability of foundation piles under the horizontal displacement failure mode.When the coefficient of variation increases from 0.1 to 1.0,the foundation piles failure probability of cohesion random field,internal friction angle random field and combined random field increases by 20.7%,9.3%and 26.2%respectively.For different autocorrelation functions,the corresponding failure probability calculation values from small to large are normal distribution type,exponential type,exponential cosine type,trigonometric type and second-order autoregressive type.The horizontal bearing failure probability of foundation piles increases with the increase of the correlation coefficientρ_(c),φ,and decreases with the decrease of the stability of random field.

关 键 词：桥梁工程 桩基础 随机场 可靠性 水平承载特性 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]