基于Mindlin解的盾构施工引起的地表变形规律研究

发布时间：2018-03-29 01:05

本文选题：砂卵石地层　切入点：盾构施工　出处：《沈阳工业大学》2017年硕士论文

【摘要】：自我国修建第一条地铁隧道至今的半个世纪里,我国已有40余个城市已建、正建或筹建地铁。盾构法以效率高、安全性好、适应力强等特点广泛应用于地铁隧道建设中,但仍会对周围土体产生扰动影响,并表现为地表沉降或隆起。过大的地表沉降或隆起将严重影响到地铁隧道盾构施工的安全性,以及地铁穿越路径上道路、高架桥、住宅等建构筑物的正常使用,因而对地铁隧道盾构施工引起地表变形量的预测是十分必要的。为了更好地预测地铁盾构机穿越对砂卵石地层的影响,回顾地铁隧道盾构施工引起地表变形量预测方法,分析、归纳了各类预测方法的优势与不足;对盾构施工中同步注浆阶段引起的地层变形进行研究,假定土体不排水,在砂卵石地层中盾构隧道同步注浆扩散半径及压力分布的研究基础上,利用Mindlin解推导出地铁隧道盾构过程中同步注浆阶段地层三维变形计算公式;在同步注浆引起的地层三维变形计算式的基础上,同时考虑地层损失与盾壳摩擦力的影响,对Sagaseta法进行修正,得出盾构施工引起的砂卵石地层地表变形预测计算式,即修正Sagaseta法。为了验证修正Sagaseta法的正确性,以沈阳地铁某区间段为例,利用修正Sagaseta法预测砂卵石地层中盾构施工引起的地表纵向与横向沉降;考虑砂卵石地层中同步注浆压力分布情况,利用MIDAS/GTS对该区段盾构施工过程进行三维数值模拟。将纵横向沉降理论值分别与工程监测数据、Sagaseta理论值、数值模拟值比较,结果表明:理论值与工程监测值较为吻合;理论较Sagaseta法更适合于砂卵石地层,较数值模拟法能更好地反映出地表变形规律。修正Sagaseta法对砂卵石地层盾构施工引起的地表变形预测有重要的参考意义。
[Abstract]:In the half century since the first subway tunnel was built in our country, more than 40 cities in China have been built, and subway is being or is being built. The shield method is widely used in subway tunnel construction with the characteristics of high efficiency, good safety, strong adaptability and so on. However, it will still affect the surrounding soil mass, and be expressed as surface subsidence or uplift. Excessive surface subsidence or uplift will seriously affect the safety of shield tunneling, and subway crossing roads, viaducts, viaducts, It is necessary to predict the surface deformation caused by shield tunneling of subway tunnel because of the normal use of building structures such as residential buildings, in order to better predict the influence of shield machine crossing on sand and pebble strata. This paper reviews the prediction methods of ground surface deformation caused by shield tunneling in subway tunnel, analyzes the advantages and disadvantages of various forecasting methods, studies the formation deformation caused by synchronous grouting in shield tunneling, and assumes that the soil is undrained. On the basis of the research on the diffusion radius and pressure distribution of synchronous grouting in the shield tunnel in sand pebble formation, the three-dimensional deformation calculation formula of the stratum in the synchronous grouting stage of the subway tunnel is derived by using the Mindlin solution. On the basis of the calculation formula of 3D formation deformation caused by synchronous grouting, and considering the influence of formation loss and shield shell friction, the Sagaseta method is revised, and the prediction formula of sand pebble ground deformation caused by shield construction is obtained. In order to verify the correctness of the modified Sagaseta method, the modified Sagaseta method is used to predict the longitudinal and transverse settlement of the surface caused by shield tunneling in the sand and gravel strata, taking a certain section of Shenyang Metro as an example. Considering the distribution of simultaneous grouting pressure in sand and gravel strata, the 3D numerical simulation of shield tunneling process in this section is carried out by using MIDAS/GTS. The theoretical values of longitudinal and horizontal settlement are compared with the Sagaseta theory and numerical simulation values of engineering monitoring data, respectively. The results show that the theoretical values are in good agreement with the engineering monitoring values, and the theory is more suitable for sand and gravel formations than the Sagaseta method. Compared with the numerical simulation method, the modified Sagaseta method can better reflect the law of surface deformation, and the modified Sagaseta method has important reference significance for prediction of surface deformation caused by shield tunneling in sand and gravel strata.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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