上海软土深埋盾构施工引起的土压时效规律分析  

Field Measurement of Time-dependent Variation of Earth Pressure Caused by Deep Tunneling in Shanghai Soft Soil

作　　者：刘树佳 白廷辉[2,3] 廖少明[3] Liu Shujia;Bai Tinghui;Liao Shaoming(Shanghai Chengpei Enterprise Management Consulting Co.,Ltd.,Shanghai 200232,P.R.China;Shanghai Water Authority,Shanghai 200050,P.R.China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,P.R.China)

机构地区：[1]上海城培企业管理咨询有限公司,上海200232 [2]上海市水务局,上海200050 [3]同济大学地下建筑与工程系,上海200092

出　　处：《地下空间与工程学报》2021年第1期229-236,共8页Chinese Journal of Underground Space and Engineering

基　　金：国家973计划(2015CB057806);国家自然科学基金项目(52090082)。

摘　　要：针对上海软土地区深埋盾构开挖所引起的土压力时效性发展规律,选取4倍直径埋深盾构,布设土压力全断面长期监测点,获取盾构开挖阶段及后期固结蠕变阶段的土压力数据,以得到深部地层的土压时效变化规律。通过现场试验可得,盾构开挖所采取的土仓压力按照理论静止土压力取值时,刀盘周围会形成半径为1~1.5D的被动土拱效应作用区域,土拱范围内会产生20%的被动土压力增幅,土拱以外的范围不受开挖扰动影响。盾构掘进所产生的被动土拱挤压效应在盾尾注浆浆液硬化后开始逐渐衰减,衰减主要作用阶段为开挖后1~3年,深层土体衰减后进入长期蠕变阶段。试验表明,软土深部地层盾构开挖会产生一定程度的土拱效应,且土拱效应在后期固结蠕变过程中逐步衰减,可为今后软土深部地层盾构隧道设计及施工的土压力取值提供一定参考依据。Aiming at the time-dependent development law of soil arching effect caused by shield excavation in deep stratum in Shanghai soft soil area,the shield crossing section with tunnel in buried depth of four times diameter is selected to lay the long-term monitoring points for the earth pressure of the whole section,which can help to obtain the full-section earth pressure data of shield excavation stage and consolidation creep stage in deep soft soil stratum.The test results show that when the theoretical static earth pressure is adopted to be shield chamber pressure in tunneling process,an ellipsoidal passive soil arching effect zone with radius of 1 ~ 1.5 time diameter will be formed around the shield cutter-head. The passive earth pressure will increase by 20% in the range of soil arching action,and the earth pressure outside the soil arching zone will not be affected by excavation disturbance. The passive soil arching effect produced by shield tunneling in deep soft soil stratum begins to attenuate gradually after the grouts hardening at the tail of shield. The main stage of attenuation is 1-3 years after the completion of excavation. After the soil arching effect attenuating,soil in deep stratum enters the long creep stage. The test results show that shield tunneling in deep soft soil stratum will produce a certain degree of soil arching effect. The soil arching effect will gradually attenuate during the later consolidation creep process,which provides a certain reference for the earth pressure in the design and construction of shield tunnels in deep soft soil.

关 键 词：软土地层 深埋盾构 土拱效应 时效特性 长期监测 

分 类 号：O319.56[理学—一般力学与力学基础]