考虑黏土蠕变特性的大埋深盾构复推总推力增量解析解研究

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中文摘要：由于黏土存在蠕变效应,黏土地层中盾构长时间停机会诱发盾构复推总推力增量过大、盾构姿态难以控制、管片易破损等次生风险等问题,将黏土地层视为Burgers黏弹性体,构建考虑地层应力和蠕变特性的大埋深圆截面隧洞简化力学模型,根据黏弹性理论推导盾壳-地层径向接触应力的黏弹性解,进而通过积分和分段计算求解复推总推力增量与停机时间的理论关系式.结合水工盾构隧洞停机实例,对比复推总推力增量实际值与理论值.研究结果表明:复推总推力增量实际值与理论值平均相对误差为13.81%,验证了该解析解的可靠性;隧洞埋深越大,复推总推力增量越大,表明大埋深段停机需更关注复推推力控制;盾壳-地层界面摩阻力随超挖间隙增大而减小,而复推总推力增量随之增大;此外,总推力增量随着盾壳-地层界面摩擦因数减小而显著减小.因此,设置合适的超挖间隙和长时间停机时采取往盾壳外注入膨润土等润滑减阻措施能有效预防大埋深段停机的次生风险.

外文标题：Study of analytical solution of total thrust increment required for shield resuming tunneling considering creep characteristics of clay

外文摘要：Due to clay creep characteristics,the long-term shield shutdown in the clay stratum will induce secondary risks such as excessive increase in the total thrust,difficult attitude control for shield tunnelling and the segment breakage.In this study,the creep characteristics were described by Burgers'constitutive relation.The mechanical model of deep-buried shield tunnel in clay stratum considering its weight was established.The viscoelastic solution of the contact stress between shield and surrounding stratum was derived based on the viscoelastic theory.The theoretical relation of the total thrust increment required for shield resuming tunneling and the shutdown time was obtained by integral and segment calculation.According to the shutdown examples of hydraulic tunnel,the measured and theoretical values of the total thrust increment were compared.The results show that the average relative error of the measured and theoretical values of the total thrust increment is 13.81%,which verifies the reliability of this analytical solution.The deeper the buried depth,the greater the total thrust increment,indicating that more attention should be paid to the thrust control when the shield resumes tunnelling after the shutdown at the deep buried tunnel.With the increase of the over-excavation clearance,the friction resistance of the shield shell decreases while the total thrust increment increases,and the total thrust increment decreases with the decrease of the friction coefficient.Therefore,it is effective for the secondary risk prevention during shutdown at deep buried tunnels to set appropriate over-excavation clearance and inject bentonite into the clearance for lubrication.

外文关键词：

creep characteristics of claycontact stress between shield and surrounding stratumtotal thrust increment required for shield resuming tunnelingover-excavation clearancefriction coefficient

作者：

王树英、钟嘉政、付循伟、龚振宇

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作者单位：

中南大学土木工程学院,湖南长沙,410075

中南大学隧地工程研究中心,湖南长沙,410075

中南大学轨道交通工程结构防灾减灾湖南省重点实验室,湖南长沙,410075

中国土木工程集团有限公司,北京,100038

中铁五局集团电务工程有限责任公司,湖南长沙,410205

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关键词：

黏土蠕变特性盾壳-地层接触应力复推总推力增量超挖间隙摩擦因数

基金：

国家自然科学基金资助项目湖南省研究生科研创新项目

项目编号：

520221122020zzts152

出版年：

2024

DOI：

10.11817/j.issn.1672-7207.2024.01.012

中南大学学报(自然科学版)

中南大学

中南大学学报(自然科学版)

CSTPCD北大核心

影响因子：0.938

ISSN：1672-7207

年,卷(期)：2024.55(1)

参考文献量20