\r张天奇^{1, 2}，葛隆博^{1, 2}，郑 刚\r^{1, 2}\r
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AuthorsHTML:\r张天奇^{1, 2}，葛隆博^{1, 2}，郑 刚\r^{1, 2}\r
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AuthorsListE:\rZhang Tianqi^{1, 2}，Ge Longbo ^{1, 2}，Zheng Gang\r^{1, 2}\r
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AuthorsHTMLE:\rZhang Tianqi^{1, 2}，Ge Longbo ^{1, 2}，Zheng Gang\r^{1, 2}\r
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Unit:\r1. 天津大学建筑工程学院，天津 300072；
2. 滨海土木工程结构与安全教育部重点实验室(天津大学)，天津 300072\r
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Unit_EngLish:\r1. School of Civil Engineering，Tianjin University，Tianjin 300072，China；
2. Key Laboratory of Coast Civil Stucture Safety of Ministry of Education(Tianjin University)，Tianjin 300072，China\r
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Abstract_Chinese:\r城市地铁线路网络渐趋密集，经常出现隧道近接既有建、构筑物施工的情况，变形控制要求严格，故精细预测隧道施工引起的地表及深层土体变形尤为必要．相较于黏土地层，砂土地层中隧道开挖引起的地表及深层土体变形十分复杂，具体表现为：隧道开挖过程中，地表以下土体的体积将随隧道土体损失率V_t的改变而发生改变，之前所提出的土体变形模式均不能很好地解释砂土中隧道开挖引起的土体体积变化行为．以之前的砂土隧道模型试验为研究对象，建立数值模型，对试验过程中地表以下土体的体积响应进行分析．研究发现，隧道开挖时，隧道周围土体的体积响应与应力路径密切相关，不同应力路径下的土体体积响应有所不同．数值结果表明，根据不同位置处应力路径特点，地表以下土体可被分成4 个特征区域，地表及地表以下不同深度位置处获得的土体损失率(V_s 和V_sub)与隧道土体损失率V_t之间的差异均可通过4个特征区域的土体体积变化来解释．\r
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Abstract_English:\rMetro line networks are becoming denser in urban areas．Tunnels are frequently constructed in close proximity to adjacent buildings or structures，requiring strict deformation control．It is essential to accurately predict soil deformation of the ground surface as well as subsurface．Both surface and subsurface soil deformation induced by tunneling is more complex in sand as compared to clay．More specifically，subsurface soil volume would change with tunnel soil volume loss V_t during the tunneling process．Soil deformation patterns proposed previously could not properly explain soil volume change behavior in sand during tunnel construction．In this study，a numerical model was established based on a previous tunnel model test to analyze subsurface soil volume response．The results showed that soil volume response around tunneling is closely related to the stress path，and the soil volume responses at different stress paths are not the same．According to numerical analysis results，subsurface soil can be divided into four characteristic zones，based on different features of the stress path at each location．The differences between V_s，V_sub(surface and subsurface soil volume loss，respectively，at different buried depths)，and V_t(tunnel soil volume loss)could be explained using soil volume changes in these four zones．\r
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Keyword_Chinese:砂土；隧道；地表；深层土体；沉降；体积变化行为；应力路径\r

Keywords_English:sand；tunnel；ground surface；deep soil；settlement；volume change behavior；stress path\r


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