宁波轨道交通盾构隧道地表变形规律研究

发布时间：2018-04-25 07:13

本文选题：盾构隧道 + 地表沉降　；参考：《宁波大学》2014年硕士论文

【摘要】：盾构法施工技术具有机械化程度高、掘进速度快、对地层扰动相对较小、环境影响程度低等特点，在城市轨道交通工程中受到广泛应用。尽管，盾构法施工较明挖隧道扰动小，但仍然对土层有一定扰动，对隧道、管线、路面、临近建筑物和构筑物都会产生一系列不利影响。由于宁波属于软土地区，场地施工条件并不是很好，地下水位高，土层的含水率高，软土压缩性高、强度低、灵敏度高、透水性低，无论是设计还是施工均缺少盾构法施工对周边环境影响规律的研究和道路与地表建筑物沉降控制及其防治技术的经验，尚存在许多需要深究的技术问题。为此，本文以宁波轨道交通1号线和2号线部分区间为工程背景，研究了土压平衡盾构在宁波地区施工引起的地表和深层土体的变形特征。主要内容包括： 1、选取典型区间监测断面，结合所处地层特性和盾构施工参数，，对盾构掘进过程中各断面的单线横向地表沉降特征、双线横向地表沉降特征以及随着盾构推进纵向地表沉降变化特征进行了分析研究。 2、选取典型区间监测断面，结合所处地层特性和盾构施工参数，对盾构掘进对深层土体在垂直于盾构轴线方向的水平位移进行了研究，并得到了盾构开挖对周边深层土体的影响范围。 3、统计了100组单线地表横向沉降数据，采用最小二乘法和一元线性回归对实测沉降槽曲线进行拟合，并与Peck预测公式相比较，反算得出沉降槽宽度系数K和地层损失率Vl的分布范围和概率密度，并给出建议值。 4、采用Flac3D有限差分程序，对盾构开挖过程进行了模拟。引入了等代层模拟盾构管片外围浆液与土的混合物，考虑了盾尾壁后注浆后浆液硬化、浆液压力消散过程，运用理论与数值计算软件推导出了在不同注浆压力下浆液压力的变化方程，分析和总结了注浆量、注浆压力、土舱压力三个因素对地表沉降的影响规律，并将实测值与计算值对比分析。
[Abstract]:Shield construction technology is widely used in urban rail transit engineering because of its high degree of mechanization, high speed of excavation, relatively small disturbance to strata and low degree of environmental impact. Although the shield tunneling method has less disturbance than the open excavation tunnel, it still has a certain disturbance to the soil layer, which will have a series of adverse effects on the tunnel, pipeline, road surface, adjacent buildings and structures. Because Ningbo belongs to the soft soil area, the site construction condition is not very good, the underground water level is high, the soil moisture content is high, the soft soil compressibility is high, the strength is low, the sensitivity is high, the water permeability is low, Both design and construction lack the research on the influence law of shield construction on the surrounding environment, the experience of settlement control and prevention technology of road and surface buildings, and there are still many technical problems that need to be studied deeply. In this paper, the deformation characteristics of surface and deep soil mass caused by earth pressure balance shield tunneling in Ningbo area are studied in the background of some sections of Ningbo Rail Transit Line 1 and Line 2. The main elements include: 1. Select the monitoring section of typical section, combine the stratigraphic characteristics and shield construction parameters, and analyze the single line lateral surface subsidence characteristics of each section during shield tunneling. The characteristics of horizontal surface subsidence along double lines and the variation characteristics of longitudinal surface subsidence with shield tunneling are analyzed and studied. 2. Selecting the monitoring section of typical section, combining the characteristics of stratum and the parameters of shield construction, the horizontal displacement of deep soil in the direction perpendicular to the axis of shield tunneling is studied. The influence range of shield excavation on surrounding deep soil is obtained. (3) 100 groups of lateral surface subsidence data of single line are counted, and the measured settlement trough curve is fitted by least square method and linear regression, and compared with Peck prediction formula. The distribution range and probability density of subsidence trough width coefficient K and formation loss rate Vl are obtained and the suggested values are given. 4. The excavation process of shield is simulated by Flac3D finite difference program. The equivalent layer is introduced to simulate the mixture of slurry and soil around the shield segment, and the process of slurry hardening and slurry pressure dissipation is considered. The variation equation of grouting pressure under different grouting pressure is deduced by using theory and numerical calculation software. The influence of grouting quantity, grouting pressure and soil chamber pressure on surface subsidence is analyzed and summarized. The measured value is compared with the calculated value.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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