College of Construction Engineering, Jilin University, Changchun, 130026, China.
China Railway 14th Bureau Group Co. Ltd., Jinan, 250101, China.
Sci Rep. 2022 Dec 30;12(1):22606. doi: 10.1038/s41598-022-27206-7.
Urban rail transit is widely used in major cities worldwide due to its high efficiency, safety, and environmental friendliness. Shield construction has a fast excavation speed and a negligible impact on ground transportation; thus, it is the preferred construction method for urban rail transit tunnels. Mudstone is a widely distributed soft rock characterized by large deformation, low strength, and significant rheological differences in different areas. Mudstone causes problems in the design and construction of subways. This paper uses finite element analysis to establish a three-dimensional numerical model of a double-line tunnel in a weathered mudstone area and analyze the influence of the stratum, design, and construction parameters on surface settlement and deformation during asynchronous and simultaneous shield construction. The research results show that the lateral surface settlement curve obtained from the simulation is consistent with the measured data, demonstrating the reliability and feasibility of the three-dimensional numerical model. The surface settlement is affected by the deformation modulus, cohesion, and the angle of internal friction, and the deformation modulus has the most significant impact. The surface settlement decreases as the buried depth of the tunnel or the distance between the two center lines of the two tunnels increases. As the buried depth of the double-lane tunnel decreases or the distance between the two center lines of the two tunnels increases to a certain value, the lateral surface settlement curve exhibits two peaks. The surface settlement shows a decreasing trend with an increase in the thrust of the shield machine and an improvement in the grouting quality. However, excess grouting pressure causes surface uplift and a subsequent increase in surface subsidence.
城市轨道交通由于其高效、安全和环保的特点，在世界各大城市得到广泛应用。盾构施工具有掘进速度快、对地面交通影响小等优点，因此成为城市轨道交通隧道建设的首选方法。泥岩是一种广泛分布的软岩，具有大变形、低强度和不同地区显著流变差异等特点。泥岩给地铁的设计和施工带来了问题。本文采用有限元分析方法，建立了风化泥岩地区双线隧道的三维数值模型，分析了地层、设计和施工参数对盾构法异步和同步施工过程中地表沉降和变形的影响。研究结果表明，模拟得到的地表横向沉降曲线与实测数据吻合较好，验证了三维数值模型的可靠性和可行性。地表沉降受变形模量、黏聚力和内摩擦角的影响，其中变形模量的影响最为显著。地表沉降随隧道埋深或两隧道中心线间距的增大而减小。随着双隧道埋深的减小或两隧道中心线间距增大到一定值，地表横向沉降曲线呈现双峰形态。随着盾构机推力的增大和注浆质量的提高，地表沉降呈减小趋势。然而，过量的注浆压力会导致地表隆起，进而导致地表沉降增加。
