地铁盾构同步注浆对地表沉降的影响规律及机理研究

发布时间：2018-05-22 13:41

本文选题：注浆参数 + 刚度迁移法　；参考：《太原理工大学》2017年硕士论文

【摘要】：盾构隧道施工中壁后注浆至关重要,通过研究其对地表沉降的影响规律及特征机理可为地铁的安全高效建设提供一定的参考依据。现有大部分研究均是单独分析各注浆参数如注浆量、注浆压力、注浆材料等影响地层变形或应力,并未分析多因素调整条件下地层变形规律。同时,由于太原市特有的工程地质和水文地质条件,在地铁隧道施工时,更应加强壁后注浆对地层变形以及土体位移的影响研究。本文以太原市地铁二号线一期工程中心街西站——南中环街站为背景,以理论分析和数值模拟为主要研究方法,研究盾构隧道施工过程中土层应力及稳态,结果表明:在隧道开挖面出现应力集中现象,隧道开挖引起周围一定范围土体和地表土层的剪切破坏;随着盾构的推进,隧道周围土体发生失稳破坏的范围变化较小,而地表塑性屈服范围逐步向两侧扩展;利用FLAC3D模拟盾构隧道施工时采用刚度迁移法,揭示隧道开挖完成后横向、轴向地表沉降及管片位移规律:横向地表沉降呈对称“凹槽”型,隧道轴线上部地层沉降最显著,地层变形量随距轴线距离的增大而减小,直至一定范围之后趋于稳定,其主要影响区域为距隧道轴线20m处(约3D);轴向地表沉降沿隧道推进方向变化相对较小,且盾构推进过程中,轴向地表沉降呈“S”型曲线;管片变形整体呈顶部管片下沉、底部管片上浮、左右侧管片产生远离隧道轴线的位移;从横向、轴向地表沉降及管片位移对考虑与不考虑浆体凝固进行对比研究,两者差异显著,表明在利用数值模拟软件模拟盾构施工全过程时,刚度迁移法的运用是必不可少的;分别研究注浆量、注浆压力、注浆材料弹性模量、泊松比对横向、轴向地表变形以及管片位移的影响规律:注浆参数的增大均能有效控制横向、轴向地表沉降及顶部管片的下沉;而底部管片上浮及左右侧管片位移均随注浆参数的增大而增大;注浆参数对于管环位移影响显著性均为:底部管片上浮顶部管片下沉右侧管片侧移;综合分析各注浆参数对横向、轴向地表沉降及管片各关键部位的位移影响,注浆量不宜超过150%;注浆压力宜取0.35-0.45MPa;注浆材料弹性模量取值为1.0-1.5MPa,泊松比不宜超过0.3;在此基础上,以横向最大地表沉降、轴向最大地表沉降以及底部管片上浮为指标,利用正交试验综合分析注浆参数对隧道及地表变形的影响,采用多元回归方法得到隧道及地表变形与各注浆参数间的相关规律:利用正交试验分析壁后注浆注浆量(A)、注浆压力(B)、注浆材料弹性模量(C)、泊松比(D)对地表沉降的影响显著性为:横向和轴向地表沉降以及底部管片的上浮均为ACDB;利用数值模拟将注浆层划分为上下两部分,研究不均匀注浆对于地表沉降及管片位移的影响,为后续工程施工提供参考依据。结果表明:不均匀注浆不影响地表沉降及管片整体变形规律;不均匀超注浆和注浆压力“上小下大”对地表沉降有所控制;不均匀注浆呈“上小下大”时会加剧底部管片的上浮。
[Abstract]:The post grouting in the shield tunnel is very important. Through the study of its influence on the surface subsidence and its characteristic mechanism, it can provide a certain reference for the safe and efficient construction of the subway. Most of the existing studies are the separate analysis of the grouting parameters such as grouting, grouting pressure, grouting material and so on. At the same time, because of the special engineering geology and hydrogeological conditions in Taiyuan, the influence of the post grouting to the deformation of the stratum and the displacement of the soil should be strengthened in the construction of the subway tunnel. This paper is based on the west station of the central street of the central street of the Metro Line No. two of Taiyuan City, South Zhong ring Street Station On the basis of theoretical analysis and numerical simulation, the stress and steady state of the soil layer during the tunnel construction are studied. The results show that the stress concentration phenomenon occurs on the tunnel excavation surface. The tunnel excavation causes the shear failure of the surrounding soil and the earth's soil layer around the tunnel. With the advance of the shield, the soil around the tunnel is unstable and destroyed. The range of range change is small, and the surface plastic yield range is gradually extended to both sides. Using the stiffness transfer method to simulate the construction of shield tunnel with FLAC3D, the transverse, axial surface settlement and displacement law of the tube are revealed after the tunnel excavation is completed. The lateral surface subsidence is symmetrical "groove" type, the upper stratum settlement in the upper part of the tunnel axis is the most significant and the formation deformation is the most. The length of the distance decreases with the distance of the distance axis, and then tends to be stable until a certain range. The main influence area is at the distance from the tunnel axis 20M (about 3D); the axial surface subsidence is relatively small along the direction of the tunnel propulsion, and the axial surface subsidence is "S" curve during the process of shield propelling; the deformation of the pipe is on the top of the tube and bottom. The displacements of the left and right sides of the tube are floating away from the axis of the tunnel. The comparison of the lateral, the axial surface settlement and the displacement of the tube is compared with the non consideration of the slurry solidification. The difference is significant. It shows that the application of the stiffness transfer method is essential in the simulation of the whole process of shield construction by using the numerical simulation software. Pulp volume, grouting pressure, modulus of elasticity of grouting material, lateral deformation of Poisson ratio, axial surface deformation and displacement of tube, the increase of grouting parameters can effectively control transverse, axial surface settlement and top pipe sinking; and the displacement of bottom pipe and left and right side pipe increase with grouting parameter increasing; grouting parameter The significant effect of the pipe ring displacement is that the tube sheet on the bottom of the bottom is moved to the right side of the tube, and the effect of the grouting parameters on the lateral, the axial surface settlement and the displacement of the key parts of the pipe should not exceed 150%; the grouting pressure should be 0.35-0.45MPa; the modulus of elasticity of the grouting material is 1.0-1.5MPa, Poisson's modulus The ratio is not more than 0.3. On this basis, the influence of grouting parameters on tunnel and surface deformation is synthetically analyzed by orthogonal test, using the maximum surface subsidence, the axial maximum surface settlement and the floatation of the bottom tube, and the correlation law between the tunnel and the surface deformation and the parameters of the grouting is obtained by the multiple regression method. The experimental analysis of grouting volume (A), grouting pressure (B), modulus of elasticity of grouting material (C) and Poisson's ratio (D) have a significant effect on surface settlement: horizontal and axial surface subsidence and the floatation of the bottom pipe are ACDB; the grouting layer is divided into two parts by numerical simulation, and the surface subsidence and the tube sheet are studied by the uneven grouting. The effect of displacement provides reference for the construction of subsequent projects. The results show that uneven grouting does not affect the surface settlement and the law of overall deformation of the tube; the uneven supergrouting and grouting pressure are "small and big" control the surface settlement, and the uneven grouting will increase the floatation of the bottom pipe when the uneven grouting is "small and big".
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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