地铁车站下水平冻结过程中冻胀的热−水−力耦合模型研究  

Thermo-hydro-mechanical coupling model of frost heave during horizontal freezing under subway station

作　　者：王长虹 魏永青 张海东[1] 李飞 WANG Chang-hong;WEI Yong-qing;ZHANG Hai-dong;LI Fei(Department of Civil Engineering,School of Science and Technology of Mechanics and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学力学与工程科学学院土木工程系,上海200444

出　　处：《岩土力学》2024年第9期2775-2785,2796,共12页Rock and Soil Mechanics

基　　金：上海市社会发展科技攻关项目(No.21DZ1204300)。

摘　　要：随着地下空间大规模开发利用,人工冻结法在隧道下穿上覆结构工程中得到广泛应用,但上覆结构对冻胀变形控制要求也越来越高,而上覆既有结构与冻结法工艺的相互作用规律尚不明晰。为此,提出多物理场耦合冻胀变形计算方法。依托上海地铁18号线国权路站下穿既有10号线上部运营车站的盾构隧道工程,以上海第⑤_(1)层灰色黏土为对象,研究新建隧道冻结法施工对上部运营车站主要结构的扰动作用。以孔隙比、冻结温度和平均水压力为耦合变量,考虑水分迁移,推导冻胀变形公式,改进热−水−力耦合的冻胀计算模型。基于黏性土的冻胀试验,获得冻胀试样的应力−应变关系,描述黏性土孔隙结构的变化规律。利用软件COMSOL Multiphysics的弱形式模块,开展热−水−力三场耦合数值模拟。结果表明:模拟结果与监测数据具有较高的拟合度,并小于预定的控制值,验证了耦合理论的正确性。研究成果可为类似冻结下穿隧道工程,提供一种多物理场耦合作用的上覆结构变形计算方法;为下穿隧道工程冻结法设计及施工提供有效的计算参数;为制定下穿隧道工程冻结法加固施工的安全控制指标,提供科学依据。The artificial freezing method is commonly used in tunneling beneath overlying structures due to the significant development and utilization of underground space.However,there is a growing demand for controlling frost heave deformation in overlying structures and the interaction laws of these structures during freezing and undercutting remain unclear.Hence,a multi-physics coupling deformation calculation method is proposed.This study focuses on the shield tunneling project of Shanghai Metro Line 18 at Guoquan Road Station,which intersects with the existing upper operating station of Line 10.It investigates the construction approach for new tunnels during freezing,using the gray clay of layer ⑤_(1) in Shanghai as the research target,particularly examining the disruptive effects on the primary structures of the upper operating station.Considering water migration,we derived the frost heave deformation formula and developed an improved thermo-hydro-mechanical coupling theory model by using pore ratio,freezing temperature,and average water pressure as coupling variables.Through frost heave tests on cohesive soil,we obtained the stress-strain relationship of frost heave specimens to describe the changes in pore structure.Subsequently,a thermo-hydro-mechanical three-field coupling numerical calculation was conducted using the weak form module(PDE)of COMSOL Multiphysics software.The simulation results closely matched the monitoring data and were below the predetermined control value,validating the accuracy of the enhanced coupling theory.These findings offer a multi-physics coupling approach for calculating deformations in similar frozen underpass tunnels,serving as a valuable reference for freezing method design and construction parameters.Additionally,we propose safety control indicators for reinforcement construction based on this scientific groundwork.

关 键 词：下穿隧道 人工冻结法 黏性土 孔隙比 热−水−力耦合 

分 类 号：U231[交通运输工程—道路与铁道工程]