深圳地铁富水软弱地层工程性质及开挖后沉降特征研究  

Study of Engineering Properties and Subsidence Characteristics after Driving of the Shenzhen Metro Tunnel in Water-Rich Soft Ground

作　　者：张成平[1] 张顶立[1] 韩凯航 王剑晨[1] 

机构地区：[1]北京交通大学城市地下工程教育部重点实验室,北京100044

出　　处：《现代隧道技术》2014年第4期113-120,共8页Modern Tunnelling Technology

基　　金：国家自然科学基金项目(51008015;51378002);教育部新世纪优秀人才支持计划项目(NCET-12-0770);中央高校基本科研业务费专项资金项目(2012JBZ013)

摘　　要：为研究富水软弱地层工程性质及开挖后沉降特征,文章通过室内试验对深圳地铁国贸至老街区间隧道的地层物理力学参数进行了测定和分析,结果表明:(1)该区域地层存在较大孔隙和微裂隙且相互贯通,土体压缩性高,固结沉降大;(2)地层倾向于散粒体,含水量大且含砂多,施工排水易冲刷夹带松散颗粒而导致地层损失难于控制;(3)地层强度低,隧道开挖时围岩稳定性差。以上因素导致此类地层具有开挖影响范围广、地层沉降大并易发生地表塌陷的显著特征。实测地层沉降验证了试验结论的正确性,国贸至老街区间隧道开挖引起的地表沉降最大值约为193.5 mm,地表沉降槽宽度约为80 m,并发生了2次地表塌陷事故。可见,隧道开挖引起的地层沉降与地质条件密切相关,通过地层物理力学特性预测隧道开挖引起的地层沉降是必要的和可行的。In order to study the engineering properties and characteristics of driving-induced subsidence of wa- ter-rich soft ground, the physical and mechanical parameters for the strata of the Shenzhen metro tunnel section from Guomao to Laojie were tested and analyzed by laboratory experiments. The results show that： （1） there are large pores and micro-fissures that are mutually connected, with high soil compressibility and consolidation settlement; （2） the ground is mainly composed of granular mixtures and has a high water and sand content, which leads to uncontrollable ground loss caused by construction drainage erosion; and （3） the low formation strength leads to poor stability of the surrounding rock during tunnelling. The above factors mean that this kind of ground has the obvious characteristics of a large disturbance scope, large ground settlement, and surface subsidence. Through actual measurement of ground settlement, the accuracy of the experimental results are verified; the maximum ground settlement caused by excavation of the Guomao-Laojie section is about 193.5mm, with a trough width of 80m, and surface subsidence occurring twice. Thus, the ground settlement caused by tunnel excavation is closely related to the geological conditions, and it is necessary and feasible to predict the ground settlement caused by tunnel excavation based on physical and mechanical properties.

关 键 词：浅埋隧道施工 软弱围岩 地层沉降 室内试验 现场实测 

分 类 号：U456.3[建筑科学—桥梁与隧道工程]