不同荷载方向下土压力对桩土摩阻力的影响  

Soil pressure explain for load direction effects on pile's friction bearing properties

作　　者：郭建光[1,2] 陈伟 陈晓斌 

机构地区：[1]中南大学土木建筑学院,湖南长沙410075 [2]南昌铁路局,江西南昌330002 [3]广州市建筑科学研究院,广东广州510440

出　　处：《铁道科学与工程学报》2009年第6期39-43,共5页Journal of Railway Science and Engineering

基　　金：中国博士后科学基金资助项目(20080440996)

摘　　要：结合广州新电视塔工程,采用混凝土短柱模拟工程桩,经过受压与受拉不同荷载方向下的桩侧摩擦力试验研究,研究其在抗压和抗拔力作用下桩土侧摩阻力性能变化。试验研究表明：桩与围岩相互作用在不同受力状态下表现出不同特点,抗压摩阻力特征值大于抗拔摩阻力特征值,抗压摩阻力/抗拔摩阻力为1.85左右;在试验过程中,抗压侧摩擦力大于抗拔侧摩擦力的原因在于被动土压力大于主动土压力;在工程应用中,需要抗拔分项系数γ作为抗拔力设计值的安全储备,本工程抗拔分项系数γ可取1.5-2.0。The testing research on large rock socketed pile＇ s confining bearing capacity properties were executed in the dug piles＇ bottom at c construction zone of Guangzhou new television station tower site. In these tests, the short concrete piles simulated the real piles, and the confining friction force between the short pile and the rock mass were studied. The compressing friction tests and the pulling out friction tests were executed respectively, and the confining friction data between the short pile and the rock mass were obtained to analyze confining friction parameters. The test results show that the piles＇ confining friction properties are quite different under the different compressing force conditions and the tensile force conditions, and the compressing friction are larger than the pulling out friction. The different friction ratio is about 1.85. The different friction bearing properties under the different load directions are explained well by the theoretical analysis. The reason that the compressing friction are larger than the pulling out friction is that the passive earth pressure is lager than the active earth pressure at the same condition. According to the tests analysis, a tensile partial coefficient is newly defined for the pile＇ s pulling out resistant force computation to get larger safety factor γ in the important buildings. In this new television station tower site engineering, the tensile partial coefficient γ is 1.5 - 2.0.

关 键 词：荷载方向 桩土接触面 桩土侧摩阻力 土压力理论 

分 类 号：TU471.8[建筑科学—结构工程]