超大直径极小间距泥水平衡式盾构施工的相互影响
发布时间：2019-02-17 20:01
【摘要】：由于城市地质条件的限制及地下空间的综合开发利用,在地下工程中不可避免地产生近距离大直径泥水平衡盾构双线隧道施工。如果新建隧道与已建隧道的间距较小,新建隧道的挖掘必然会改变已建隧道周围土体的应力分布状况,进而对已建隧道衬砌的受力及变形产生影响,同时也会影响新建隧道的安全施工。本文以在建的上海虹梅南路隧道工程中闵行区段存在长距离超大直径极小距离双线泥水平衡盾构掘进为工程背景,主要应用ABAQUS有限元数值分析软件建立三维弹塑性模型分析双线隧道施工相互影响,重点是在研究超大直径极小间距泥水平衡式盾构施工的相互影响的基础上,提出减少新建隧道对已建隧道的不利影响的有效措施,保证隧道施工过程中的安全,并能够为今后相关的隧道施工提供一定的参考借鉴。本文主要工作和研究成果如下:1.结合上海土质的特殊性及现场单线隧道监测数据,分析研究超大直径盾构单线施工对周围土层的扰动情况;同时从理论上探讨超大直径在软粘土中施工引起的地表沉降机理,采用修正的镜像位移法可以有效的预测地表沉降规律。2.依托实际工程,通过采用有限元数值分析软件ABAQUS建立三维模型对双线隧道施工进行数值模拟,研究在不同土层、不同埋深及不同间距下双线平行隧道地表变形机理。模拟结果显示:土层弹性模量越大地表沉降及周围土层扰动越小;其次,双线隧道间距对先建隧道稳定性影响较大,间距越小隧道间的土层扰动越大;此外盾构掘进埋深对周围土层扰动影响复杂,在不同的埋深下沉降呈现的规律不同,如当开挖面正上方土质较软时,隧道轴线上方土层相对周围土层有“隆起”趋势。3.同样借助于有限元分析软件分析在极小间距双线隧道中心线处设置不同隔离桩间距、不同隔离桩桩长等保护措施,研究双线平行隧道衬砌变形机理。结果表明设置隔离桩可以有效地减小双线隧道地表和衬砌拱顶最大沉降值以及衬砌环弯矩值;其次,隔离桩间距越密相互影响越小,但是随着隔离桩加密衬砌整体水平方向偏移值增大;同时,隔离桩桩长对双线隧道施工影响比较大,桩长越长相互影响越小。4.结合部分现场监测数据分析后建隧道对先建隧道的影响,数值模拟值与实测值结果相近,可以用于盾构推进过程中土层扰动的预测分析。
[Abstract]:Due to the limitation of urban geological conditions and the comprehensive development and utilization of underground space, it is inevitable to produce a large-diameter shield tunnel in the underground engineering. If the distance between the new tunnel and the built tunnel is small, the excavation of the new tunnel will inevitably change the stress distribution of the soil around the built tunnel, and then affect the stress and deformation of the lining of the built tunnel. At the same time, it will also affect the safety of the new tunnel construction. In this paper, the engineering background is the existence of long distance super-large diameter extremely small distance double-line mud water balanced shield tunneling in the section of Minhang District in the construction of Hongmenan Road Tunnel project in Shanghai. In this paper, ABAQUS finite element numerical analysis software is used to establish a three-dimensional elastic-plastic model to analyze the interaction between the construction of double-line tunnels. The emphasis is on the study of the interaction between the super-large diameter and minimal spacing mud-water balanced shield construction. The effective measures to reduce the adverse effects of the new tunnel on the existing tunnel are put forward to ensure the safety in the course of tunnel construction and to provide some reference for the relevant tunnel construction in the future. The main work and research results are as follows: 1. Based on the particularity of soil quality in Shanghai and the monitoring data of single-line tunnel in site, the disturbance to the surrounding soil layer caused by the single-line construction of super-large diameter shield tunneling is analyzed and studied. At the same time, the mechanism of surface subsidence caused by the construction of super-large diameter in soft clay is discussed theoretically. The modified mirror displacement method can effectively predict the law of surface subsidence. 2. Based on the actual engineering, the 3D model of double-track tunnel construction is established by using finite element software ABAQUS, and the surface deformation mechanism of double-line parallel tunnel under different soil layers, different buried depth and different spacing is studied. The simulation results show that the larger the elastic modulus of soil layer is, the smaller the surface settlement is and the smaller the surrounding soil layer disturbance is. Secondly, the interval between two tunnels has a greater influence on the stability of the first built tunnel, and the smaller the interval is, the greater the disturbance of soil layer is. In addition, the influence of shield tunneling depth on the disturbance of surrounding soil layer is complex, and the law of settlement under different burial depth is different. For example, when the soil above the excavated surface is relatively soft, the soil layer above the tunnel axis has a tendency of "uplift" relative to the surrounding soil layer. With the help of the finite element analysis software, the mechanism of lining deformation of double-line parallel tunnel is studied by means of the protection measures such as different separation pile spacing and different isolation pile length at the center line of double-line tunnel with minimal spacing. The results show that the maximum settlement value and the moment value of the lining ring can be effectively reduced by setting the isolation pile. Secondly, the closer the separation pile spacing is, the smaller the mutual influence is, but with the increase of the overall horizontal deviation value of the isolated pile, the length of the isolated pile has a greater influence on the construction of the double-line tunnel, and the longer the pile length is, the smaller the mutual influence is. 4. Combined with some field monitoring data, the influence of the post-built tunnel on the pre-built tunnel is analyzed. The numerical simulation results are similar to the measured values, which can be used to predict and analyze the soil disturbance during the shield tunneling process.
【学位授予单位】：上海理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43
本文编号：2425544
[Abstract]:Due to the limitation of urban geological conditions and the comprehensive development and utilization of underground space, it is inevitable to produce a large-diameter shield tunnel in the underground engineering. If the distance between the new tunnel and the built tunnel is small, the excavation of the new tunnel will inevitably change the stress distribution of the soil around the built tunnel, and then affect the stress and deformation of the lining of the built tunnel. At the same time, it will also affect the safety of the new tunnel construction. In this paper, the engineering background is the existence of long distance super-large diameter extremely small distance double-line mud water balanced shield tunneling in the section of Minhang District in the construction of Hongmenan Road Tunnel project in Shanghai. In this paper, ABAQUS finite element numerical analysis software is used to establish a three-dimensional elastic-plastic model to analyze the interaction between the construction of double-line tunnels. The emphasis is on the study of the interaction between the super-large diameter and minimal spacing mud-water balanced shield construction. The effective measures to reduce the adverse effects of the new tunnel on the existing tunnel are put forward to ensure the safety in the course of tunnel construction and to provide some reference for the relevant tunnel construction in the future. The main work and research results are as follows: 1. Based on the particularity of soil quality in Shanghai and the monitoring data of single-line tunnel in site, the disturbance to the surrounding soil layer caused by the single-line construction of super-large diameter shield tunneling is analyzed and studied. At the same time, the mechanism of surface subsidence caused by the construction of super-large diameter in soft clay is discussed theoretically. The modified mirror displacement method can effectively predict the law of surface subsidence. 2. Based on the actual engineering, the 3D model of double-track tunnel construction is established by using finite element software ABAQUS, and the surface deformation mechanism of double-line parallel tunnel under different soil layers, different buried depth and different spacing is studied. The simulation results show that the larger the elastic modulus of soil layer is, the smaller the surface settlement is and the smaller the surrounding soil layer disturbance is. Secondly, the interval between two tunnels has a greater influence on the stability of the first built tunnel, and the smaller the interval is, the greater the disturbance of soil layer is. In addition, the influence of shield tunneling depth on the disturbance of surrounding soil layer is complex, and the law of settlement under different burial depth is different. For example, when the soil above the excavated surface is relatively soft, the soil layer above the tunnel axis has a tendency of "uplift" relative to the surrounding soil layer. With the help of the finite element analysis software, the mechanism of lining deformation of double-line parallel tunnel is studied by means of the protection measures such as different separation pile spacing and different isolation pile length at the center line of double-line tunnel with minimal spacing. The results show that the maximum settlement value and the moment value of the lining ring can be effectively reduced by setting the isolation pile. Secondly, the closer the separation pile spacing is, the smaller the mutual influence is, but with the increase of the overall horizontal deviation value of the isolated pile, the length of the isolated pile has a greater influence on the construction of the double-line tunnel, and the longer the pile length is, the smaller the mutual influence is. 4. Combined with some field monitoring data, the influence of the post-built tunnel on the pre-built tunnel is analyzed. The numerical simulation results are similar to the measured values, which can be used to predict and analyze the soil disturbance during the shield tunneling process.
【学位授予单位】：上海理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43
【参考文献】
相关期刊论文 前2条
1 黄忠辉;季倩倩;林家祥;;超大直径泥水平衡盾构隧道抗浮结构试验研究[J];地下空间与工程学报;2010年02期
2 于宁,朱合华;盾构隧道施工地表变形分析与三维有限元模拟[J];岩土力学;2004年08期
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