软岩地基斜锚-短桩复合基础水平承载性能研究  

Investigation on Lateral Bearing Performance of Short Rock-socketed Pile Combined with Inclined Anchor Bolts in Soft Rock Mass

作　　者：向城名 田雷 侯中伟 乾增珍[3] Xiang Chengming;Tian Lei;Hou Zhongwei;Qian Zengzhen(State Nuclear Power Planning and Design Institute Chongqing Co.,Ltd.,Chongqing 401121,P.R.China;State Grid Economic and Technological Research Institute Co.,Ltd.,Beijing 102209,P.R.China;School of Engineering and Technology,China University of Geosciences,Beijing 100083,P.R.China)

机构地区：[1]国核电力规划设计研究院重庆有限公司,重庆401121 [2]国网经济技术研究院有限公司,北京102209 [3]中国地质大学(北京)工程技术学院,北京100083

出　　处：《地下空间与工程学报》2024年第4期1275-1285,共11页Chinese Journal of Underground Space and Engineering

基　　金：国家电网公司总部科技项目(5200-202256088A-1-1-ZN)。

摘　　要：针对山区输电线路岩石地基斜锚-短桩复合基础这一新型基础型式,采用有限元方法构建并验证计算模型,并进一步以短桩的桩径及其嵌岩深度、斜锚长度、斜锚连接节点距地表深度为参数,开展嵌岩短桩及斜锚-短桩复合基础抗水平承载性能对比研究。基于斜锚-短桩复合基础水平荷载-位移曲线初始弹性段、弹塑性过渡段和直线破坏段的三阶段变化特征,确定了各基础相应阶段的水平承载力。研究岩体及桩身截面混凝土应力分布特征、斜锚与短桩连接节点位置对斜锚-短桩复合基础抗水平承载性能的影响规律,结果表明:斜锚与岩体间的黏结锚固作用可将基顶水平力转化为斜锚拉力,使水平荷载传递至斜锚周围及短桩桩端以下的岩体,进而有效提高斜锚-短桩复合基础水平承载性能。通过优化斜锚连接节点距地表深度,可减小桩径及其嵌岩深度同时满足相应基础抗水平承载力设计要求,从而有效降低基础施工难度,提高基础安全性。A new composite foundation of electricity transmission lines in mountainous areas has been used in recent years,which is composed of a short rock-socketed pile and three inclined anchor bolts.In this study,the finite element method(FEM) was firstly utilized to establish and verify its FEM calculation model.In addition,the parameters of rock-socketed pile diameter and its embedded depth,inclined anchor length,and the depth of the inclined anchor connection position to the ground surface were considered to design and simulate the lateral bearing capacity of this new type composite foundation.Lateral bearing performances of the composite foundation were simulated,which were also compared to those of rock-socketed short piles without anchor bolts.According to the typical initial linear,curvilinear transition,and final linear regions of the lateral load-displacement curve of each foundation,the corresponding lateral bearing capacity was suggested.The stress distribution characteristics of the rock mass around pile body and that of the concrete section of the pile,as well as the variation of the depth of the inclined anchor connection position to the ground surface against the lateral bearing capacity indicated that the anchoring effect of the inclined anchor can convert the lateral loadings at the top of the foundation into the tension force of the inclined anchor,and can transfer the lateral load to the rock mass around the inclined anchor and below the end of the short pile,thereby effectively improving the lateral bearing capacity of the composite foundation.By optimizing the depth of the inclined anchor connection position to the ground surface,it is possible to reduce the diameter and the embedded depth of a rock-socketed pile and achieve the same lateral capacity of design requirements of transmission tower foundations.As a result,the difficulty of foundation construction can be effectively reduced,thus achieving significant safety and economic benefits.

关 键 词：斜锚-短桩复合基础 输电线路 水平承载力 数值模拟 岩石地基 

分 类 号：TU470[建筑科学—结构工程] P315-39[建筑科学—土工工程]