实验技术与管理2025，Vol.42Issue(5)：140-146,7.DOI:10.16791/j.cnki.sjg.2025.05.017
砂岩地层预应力锚索力学特性及有效锚固长度优化研究
Study on the mechanical characteristics and effective anchorage length optimization of a prestressed anchor cable in sandstone strata based on field test and numerical simulation
摘要
Abstract
[Objective]As the excavation depth increases,the tunnel support forms are diversified.Therefore,a study of a prestressed anchor cable is of great significance in tunnel construction applications.However,in existing research on anchor cables,most studies have focused on formation conditions in pebble,broken zone,and loess strata,and systematic research on a prestressed anchor cable in sandstone stratum has not been reported.This paper aims to reveal the relationship between the end load and anchor cable displacement under different working conditions,as well as the load-transfer mechanism of a prestressed anchor cable.It also seeks to optimize the effective anchorage length of the prestressed anchor cable supported by the Guobo Station project so as to provide an effective reference for the design and construction of anchor cables in tunnel engineering.[Methods]In this paper,field prestressed anchor cable pulling tests and numerical simulations are performed.First,the mechanical evolution law of prestressed anchor cable pulling under different anchorage lengths is studied through the field cable pulling test.Then,using FLAC3D finite element numerical simulation technology,the rationality of the field test data and simulation data is compared,the load-transfer mechanism of the prestressed anchor cable is further studied,and the effective anchorage length of the anchor cable under different prestressed conditions is optimized.[Results]The ultimate tensile capacities of the prestressed anchor cable with anchorage section lengths of 5 and 6 m are 509.24 and 611.69 kN,respectively,which provide a certain reference value for the design tensile value of prestressed anchor cables in tunnel design and construction.The effective anchorage lengths of 200,300 and 400 kN prestressed anchor cables are about 5,6,and 7 m,respectively.Compared with the axial force distribution of the cable,the shear stress distribution in the anchorage section is more suitable for determining the effective anchorage length.[Conclusions]Using the integral formula of shear stress to calculate the pulling force of the anchor cable end,a pulling test well can be simulated.The tensile load at the end of the anchor cable increases nonlinearly with an increase in the displacement,but the growth rate decreases gradually.With an increase in the drawing load,the force-transfer mechanism of the prestressed anchor cable is divided into three stages.In the first stage,the shear stress distribution is mainly concentrated at the beginning of the anchorage section,and shear stress is increased proportional to the drawing force.In the second stage,the shear stress distribution in the second half of the anchorage area begins to appear,the curve begins to exhibit obvious peaks,and peak shear stress gradually increases until the ultimate shear capacity per unit length is reached.In the third stage,more anchorage sections reach the shear capacity limit,and the final shear stress distribution shows a"rectangular shape."When the prestress is less than 400 kN,the curve of the load-effective anchorage length of the prestressed anchor cable completely transitions from nonlinear to linear,and the curve is suitable for studying uniform formation condition with poor soil quality.关键词
预应力锚索/现场试验/数值模拟/传力机理/有效锚固长度Key words
prestressed anchor cable/field test/numerical simulation/transfer mechanism of cable/effective anchorage length分类
交通工程引用本文复制引用
王秀博,严志成,王立川,旷文涛,章慧健,杨继康..砂岩地层预应力锚索力学特性及有效锚固长度优化研究[J].实验技术与管理,2025,42(5):140-146,7.基金项目
国家自然科学基金项目(52178395) （52178395）
中铁十八局集团有限公司科技研发项目(G23-02) （G23-02）
