土岩组合地层盖挖法车站“吊脚桩”基坑设计优化研究  

Case Study on Design Optimization of End-suspended Piles of Foundation Pit of a Cut-and-cover Metro Station in Soil-rock Combined Strata

作　　者：田海光[1] 

机构地区：[1]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《隧道建设》2015年第7期635-641,共7页Tunnel Construction

摘　　要：以青岛地铁3号线五四广场站为研究对象,对土岩组合地层地区的吊脚桩设计要点进行研究。通过数模模拟,对土岩组合地层中"吊脚桩"基坑的支护体系变形及内力、"吊脚桩"嵌岩深度与预留岩肩宽度的关系进行了分析,并对有竖向荷载的"吊脚桩"进行了研究。研究表明:1)随着开挖深度的增加及锚杆的施工,预应力锁脚锚杆对吊脚桩桩底水平位移的控制作用明显。2)随着嵌岩深度和肩岩宽度的增加,吊脚桩桩身最大水平位移呈减小趋势,嵌岩深度取2.0 m,岩肩宽度取1.5 m较为合理。3)由于桩脚嵌入中风化花岗岩,桩顶位移不受竖向荷载控制,仅随开挖深度增加而明显增加;桩身弯矩稍有增大,但变化值极小。In the paper, the design of the end-suspended piles of the foundation pit of May Fourth Square Station of Line 3 of Qingdao Metro, which is located in soil-rock combined strata, is studied. The correlation between the deformation and internal forces of the support system of the foundation pit with end-suspended piles located in soil-rock combined strata and the rock-socketed depth and rock shoulder width of the end-suspended piles is analyzed by means of numerical simulation. Furthermore, the displacement and bending moment of the end-suspended piles with vertical load and without vertical load are also studied. Conclusions drawn are as follows ： 1 ） With the increase of the cutting depth and the installation of the rock bolts, the prestressed foot-locking rock bolts have obvious effect in the control of the horizontal displacement of the ends of the end-suspended piles; 2） With the increase of the rock-socketed depth and rock shoulder width, the maximum horizontal displacement of the end-suspended piles reduces; It is proper that the rock-socketed depth should be taken as 2.0 m and the rock shoulder width should be taken as 1.5 m ; 3 ） Because the ends of the piles are socketed into the intermediately-weathered granite, the displacement of the pile top is not controlled by the vertical load, however, it increases obviously as the cutting depth increases; the bending moment of the pile increases slightly, with very small increment.

关 键 词：土岩组合地层 盖挖法地铁车站 吊脚桩 嵌岩深度 岩肩宽度 

分 类 号：U455[建筑科学—桥梁与隧道工程]