明挖深基坑桩锚体系中锚索抗拔拉基本试验总结

Summary of Basic Tests on the Pullout Resistance of Anchor Cables in the Pile Anchor System of Open Excavation Deep Foundation Pit

以在建项目重庆沿山货运通道龙台山陵园下穿道明挖基坑锚拉桩板墙施工为背景,龙台山陵园下穿通道有预应力锚索568孔,为压力分散型预应力锚索,施工前采用循环加、卸荷法进行预应力锚索基本试验,确定锚固体与岩土层间黏结强度极限标准值,验证锚索设计参数和施工工艺,为设计参数校核提供依据,保证基坑在桩锚体系支护下能安全开挖。通过试验证明预应力锚索设计参数、施工工艺、锚索极限承载力等均满足工程要求,可利用工作锚索的张拉荷载来提高锚索锚固力。

Against the background of the construction of anchor pile sheet wall in the open excavation foundation pit of Longtai Mountain Lingyuan underpass of the Chongqing Yanshan Freight Corridor under construction,there are 568 holes of prestressed anchor cables in the underpass of Longtai Mountain Lingyuan,which are pressure dispersed prestressed anchor cables.Before construction,basic tests of prestressed anchor cables are carried out using cyclic loading and unloading methods to determine the ultimate standard value of bond strength between the anchor solid and the rock and soil layer,and to verify the design parameters and construction process of the anchor cables,Provide a basis for design parameter verification to ensure that the foundation pit can be safely excavated under the support of pile anchor system.Through experiments,it has been proven that the design parameters,construction process,and ultimate bearing capacity of the prestressed anchor cable meet the engineering requirements.The tensioning load of the working anchor cable can be used to improve the anchoring force of the anchor cable.