| 基坑开挖引起的旁侧盾构隧道横向受力变化研究 |
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| 引用本文： | 魏纲,张鑫海,林心蓓,华鑫欣.基坑开挖引起的旁侧盾构隧道横向受力变化研究[J].岩土力学,2020,41(2):635-644. |
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| 作者姓名： | 魏纲 张鑫海 林心蓓 华鑫欣 |
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| 作者单位： | 1. 浙江大学城市学院 土木工程系，浙江 杭州 310015；2. 浙江大学 建筑工程学院，浙江 杭州 310058；
3. 中铁二院华东勘察设计有限责任公司，浙江 杭州 310004 |
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| 基金项目： | 国家自然科学基金（No. 51778576） |
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| 摘 要： | 为研究运营盾构隧道附近基坑开挖对隧道管片受力的影响，针对基坑开挖引起旁侧盾构隧道围压变化的机制进行了分析，提出了一种能描述隧道受力-位移-再平衡过程的附加围压重分布模型，并推导出附加围压的计算公式。采用修正惯用法计算相应围压作用下的衬砌内力。根据实际工程做算例分析，研究基坑开挖对盾构隧道围压和内力的影响，并进行影响因素分析。分析结果表明：基坑开挖前隧道围压呈“钟形”分布；当基坑开挖后，隧道两侧的围压减小，基坑开挖侧的围压减小量更多；基坑开挖会使旁侧隧道正负弯矩值和正负剪力值增大，拱顶和拱底的轴力减小；随着基坑侧壁应力释放系数的增大，附加围压和附加弯矩的绝对值都会增加，而弯矩对基坑开挖卸载的响应更为明显；埋深较浅的盾构隧道对旁侧基坑开挖的影响更敏感，埋深较大的隧道，尤其是埋深大于基坑开挖深度的隧道，对旁侧基坑开挖影响的敏感度会明显降低；随着基坑与旁侧隧道净距的增加，基坑开挖对隧道的影响也会减小。
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| 关 键 词： | 基坑开挖 旁侧盾构隧道 横向受力 围压重分布 修正惯用法 |
| 收稿时间： | 2019-02-13 |
| 修稿时间： | 2019-05-14 |
Variations of transverse forces on nearby shield tunnel
caused by foundation pits excavation |
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| WEI Gang,ZHANG Xin-hai,LIN Xin-bei,HUA Xin-xin.Variations of transverse forces on nearby shield tunnel
caused by foundation pits excavation[J].Rock and Soil Mechanics,2020,41(2):635-644. |
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| Authors: | WEI Gang ZHANG Xin-hai LIN Xin-bei HUA Xin-xin |
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| Institution: | 1. Department of Civil Engineering, Zhejiang University City College, Hangzhou, Zhejiang 310015, China;
2. College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang 310058, China;
3. CREEC East China Survey and Design Co., Ltd., Hangzhou, Zhejiang 310004, China |
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| Abstract: | In order to study the influence of excavation near shield tunnels on the force of tunnel segments, the mechanism of surrounding pressure change on tunnels caused by nearby excavation is studied. A model of additional confining pressure redistribution is proposed which can describe the process of force-displacement-rebalancing of tunnels, and the calculation formula of additional confining pressure is deduced. The internal force of lining under the corresponding confining pressure is calculated by using the modified routine method. The influence of foundation pit excavation on the confining pressure and internal force of shield tunnels is studied based on the analysis of a practical engineering example, and the influencing factors are analyzed. The analysis results show that confining pressure of the tunnel before excavation presents a "bell shape" distribution. After excavation, the confining pressure on both sides of the tunnel decreases, and the confining pressure on the excavation side decreases more. The excavation of the foundation pit increases the positive and negative bending moments and the positive and negative shear forces of the nearby tunnel, and decreases the axial forces of the arch top and the arch bottom. With the increase of the stress release coefficient of the side wall of the foundation pit, both the absolute values of the additional confining pressure and of the additional bending moment will increase, and the response of bending moment to unloading of foundation pit excavation is more obvious. Shallow shield tunnel is more sensitive to the influence of the excavation of side foundation pit, and the influence of excavation of side foundation pit will decrease obviously when the burial depth of the tunnel is greater than that of the foundation pit excavation. With the increase of the distance between the foundation pit and the nearby tunnel, the influence of the foundation pit excavation on the tunnel will also be reduced. |
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| Keywords: | foundation pits excavation nearby shield tunnel transverse force redistribution of confining pressure modified routine method |
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