多层溶洞对桥基竖向承载特性的影响分析  

Experimental Study on the Vertical Bearing Capacity of Bridge Pile in Multi-layer Cave

作　　者：苏冠峰 贺国京[2] 易锦[2] 陈伟[2] SU Guanfeng HE Guojing YI Jin CHEN Wei(Huzhou City Construction and Development Corporation, Huzhou, Zhejiang 313000, China Central South University of Forestry and Technology, Changsha, Hunan 410000, China)

机构地区：[1]湖州市城市建设发展总公司,浙江湖州313000 [2]中南林业科技大学,湖南长沙410000

出　　处：《公路工程》2017年第1期80-84,共5页Highway Engineering

基　　金：国家自然科学基金项目(51108470);湖南省自然科学基金项目(14JJ2105);湖南省重点学科建设项目资助(2012ZDXK003)

摘　　要：利用数值模拟的方法对基桩穿越多层溶洞时溶洞参数变化(溶洞半径、溶洞间竖向相对距离、溶洞高度)对基桩承载特性的影响进行了深入分析,结果表明:溶洞半径在一定范围内变化,设计时上段与中段的岩层可以和下段岩层一起成为侧摩阻力的持力层,而当超过此范围,只有下段岩层可作为基桩侧摩阻力的持力层;上段岩层和中段岩层的厚度的变化,影响着侧摩阻力的发挥效果,对于上段岩层越接近溶洞力持力层,侧摩阻力减弱的越明显;溶洞高度增加减小了桩周与岩层接触面积,导致基桩侧摩阻力整体减弱,但下段岩层桩侧摩阻力均有所增强。Numerical simulation is used to analyze the influence of parameter variation（radius of karst cave, vertical relative distance between karst cave, karst cave height） on pile＇ s bearing behavior when the pile cross through multilayer karst cave, it turned out that the upper side and the middle segment of stratum can be bearing stratums with the lower segment of stratum when the karst cave radius changes within a certain range,but only lower segment of stratum can be bearing stratum when the pile radius ex- ceeds this range. The various thickness of upper and middle segment of stratum affects the development of side frication. When the upper side of stratum gets closer to the top of cave, side friction reduces more ob- viously. The increased height of karst cave decreases the contact area between pile lateral and stratum, which makes the pile lateral friction recede, but the pile lateral friction in lower segment of pile still in- creased.

关 键 词：多层溶洞 桥梁基桩 有限元 竖向荷载 

分 类 号：U443.1[建筑科学—桥梁与隧道工程]