基桩嵌岩段承载特性试验研究  

Experimental Study on Load Bearing Characteristic of Rock-socketed Segment in Pil

作　　者：雷勇[1] 尹君凡 陈秋南[1] 

机构地区：[1]湖南科技大学岩土工程稳定控制与健康监测湖南省重点实验室,湖南湘潭411201

出　　处：《公路交通科技》2016年第10期73-80,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51208195);岩土工程稳定控制与健康监测湖南省重点实验室开放基金项目(E21618)

摘　　要：根据滑移剪胀机理,建立了滑动剪胀阶段和剪切滑移阶段侧摩阻力的表达式,求得了滑动剪胀阶段的嵌岩段摩阻力及桩身轴力的解析式。基于所获得的解答,分析了嵌岩段摩阻力及轴力随深度变化的分布规律,并对桩端荷载分担比进行了研究。研究表明:嵌岩比l/d与综合影响系数λ对桩端荷载分担比P_b/P_d影响较大,在不同的λ下,随着嵌岩比l/d的增加,桩端荷载分担比P_b/P_d均不同程度地减小,随着l/d增大到一定值时,P_b/P_d接近于0;现场大直径嵌岩桩静载试验结果表明,正常工作状态下嵌岩桩具有摩擦桩的性质,桩侧土阻力和嵌岩段摩阻力分担荷载的比例较高,桩端阻力所占比例不大,在全加载过程中变化也不显著。最后结合理论公式反算得到计算参数,理论计算结果与实测数据吻合良好。The expressions of the pile side friction in the slide-dilatancy and shear-slip phases are established based on the mechanism of sliding-dilatancy. The analytical solution of the friction and axial force of rocksocketed segment when the surrounding rock is at sliding dilatancy stage are obtained. On the basis of the obtained analytical solution,the distribution of friction resistance and axial force along the rock-socketed segment are discussed,and the pile end load share ratio is researched. The research shows that： the rocksocketed ratio l/d and comprehensive effect coefficient λ have a greater influence on the pile end load sharing ratio Pb/Pd,under different λ values,the pile end load sharing Pb/Pddecreased to different extents with the increase of rock-socketed ratio l/d,as the l/d increases to a certain value,the Pb/Pdis closed to zero. The in-situ large diameter rock-socketed pile static load test result shows that in normal working state,the rocksocketed pile has the nature of friction pile,the pile lateral soil resistance and rock-socketed friction share higher load ratios,the pile tip resistance is small and no significant change in the whole loading process.Finally,combining with the theoretical formula,the calculation parameters are obtained by inverse. The theoretical calculation result is in good agreement with measured data.

关 键 词：桥梁工程 嵌岩段 试验研究 承载特性 荷载分担比 

分 类 号：TU473.1[建筑科学—结构工程]