| 浅埋偏压连拱隧道施工的力学响应分析 |
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| 引用本文： | 向安田,朱合华,丁文其,贾明辉. 浅埋偏压连拱隧道施工的力学响应分析[J]. 地质力学学报, 2007, 13(3): 247-254,211 |
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| 作者姓名： | 向安田 朱合华 丁文其 贾明辉 |
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| 作者单位： | 同济大学地下建筑工程系,上海,200092;同济大学地下建筑工程系,上海,200092;同济大学地下建筑工程系,上海,200092;同济大学地下建筑工程系,上海,200092 |
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| 摘 要： | 以江西某高速公路一浅埋偏压连拱隧道为背景,用MARC有限元程序对其出口段进行了动态施工的三维数值模拟。系统研究了塑性区分布和发展、拱顶下沉、正应力与剪应力的集中和转移、中隔墙竖向应力随施工过程的变化规律。研究表明:1.非对称开挖是引起中墙偏压的最关键因素,初衬和二衬的施作对改善中墙偏压作用不大,对称开挖才是最有效途径;2.在浅埋条件下,拱顶下沉有随埋深增大而增大的趋势,位移释放在开挖完成、支护之前就已经大部分完成。3.左右洞上台阶开挖后拱顶出现拉应力区,是易坍方部位,应超前或及时支护;4.由于偏压作用,山脊一侧边墙和中墙墙踵处塑性区更发育,该侧更易失稳;5.施工完毕,隧道两侧边墙附近集中的压应力转移到二衬和仰拱上,使二者成为应力集中部位,从而改善了隧道围岩的受力状况。
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| 关 键 词： | 三维数值模拟 偏压 拱顶下沉 塑性区 应力集中 |
| 文章编号： | 1006-6616（2007）03-0247-08 |
| 收稿时间： | 2006-11-10 |
| 修稿时间： | 2006-11-10 |
MECHANIC RESPONSE OF A SHALLOW-EMBEDDED AND DOUBLE-ARCH TUNNEL UNDER PARTIAL PRESSURES DURING CONSTRUCTION |
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| XIANG An-tian,ZHU He-hu,DING Wen-qi,JIA Ming-hui. MECHANIC RESPONSE OF A SHALLOW-EMBEDDED AND DOUBLE-ARCH TUNNEL UNDER PARTIAL PRESSURES DURING CONSTRUCTION[J]. Journal of Geomechanics, 2007, 13(3): 247-254,211 |
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| Authors: | XIANG An-tian ZHU He-hu DING Wen-qi JIA Ming-hui |
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| Affiliation: | Geotechnic Engineering Institute, Tongji University, Shanghai 200092, China,Geotechnic Engineering Institute, Tongji University, Shanghai 200092, China,Geotechnic Engineering Institute, Tongji University, Shanghai 200092, China and Geotechnic Engineering Institute, Tongji University, Shanghai 200092, China |
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| Abstract: | Taking an expressway in Jiangxi province as the engineering background, the behavior of a shallow-embedded and double-arch tunnel with partial-pressure during construction is simulated.Several aspects, such as stress concentration and transfer, plastic zone distribution, vault displacement and change of vertical stress, (σy)of the mid-leading wall with construction are studied systemtically.The study indicates that:1) asymmetrical excavation is the key cause of partial pressure in the mid-leading wall and the construction of the first and second lining can not ameliorate the conditions greatly;2) under conditions of shallow embedment, vault displacement increases with embedment depth and displacement mainly happens during excavation of tunnel before lining construction;3)after excavation of the up-bench tunnel, pulling stress concentrates around the top arch and lining should be constructed promptly or beforehand;4)as a result of partial pressure, when plastic zones around the side-wall and mid-leading wall heel, which are near the mountain ridge, are better developed;and 5) when construction finished, compressive stresses at tunnel side-walls disappear and are transferred to the inverse arch and second lining, making them concentrated by shear stress and normal stress and improving the stability of the tunnel. |
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| Keywords: | 3D numerical simulation partial pressure vault displacement plastic zone stress concentration |
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