软土地层中盾构施工引起地表沉降规律研究

发布时间：2018-05-31 10:10

本文选题：地铁隧道 + 地表沉降　；参考：《浙江工业大学》2014年硕士论文

【摘要】：盾构法以其独有的智能化、安全、快捷等特点和优势迅速成为我国地铁工程中一种重要的施工方法,在地下工程中得到广泛的推广和应用。但是,由于盾构施工不可避免的会引起地面沉降和变形,当地表沉降过大时可能危及周围建筑物和地下管线等的安全,造成严重的经济损失和社会影响。本文以杭州地铁二号线振宁路站～外环路站区间(9号盾构区间)隧道工程为工程背景,采用实例分析和三维数值模拟等手段对地铁隧道盾构施工引起的地表沉降变化规律进行了研究。主要研究内容和结果如下： (1)沿纵向盾构机切口前30m以内和其后30m以内为盾构施工影响范围,而盾构机切口后30m为主要影响范围,此范围产生的地表沉降达90%以上；盾构机切口前30m以外和其后30m以外的范围不受影响或影响可被忽略。 (2)沿横向盾构单线推进时对地表主要影响区域为隧道轴线两侧6m范围内,约1倍洞径；全部影响区域为隧道轴线两侧18m,为3倍洞径。 (3)盾构施工引起地表变形是不可避免的,盾构机前方土体受扰动是引起地表沉降的重要原因；在一定的地质、相对埋深(H/D)等条件下,盾构机前方土体受扰动程度与盾构土仓压力关系密切。 (4)随着土仓压力的增加,切口前方土体的地表隆起不断增加,但增加很小,后方土体的地表沉降值不断减小,且减小量远远大于隆起的增加量。超平衡状态时,地表隆起值增加,地表沉降减小,且减小量远远大于增加量；欠平衡状态时,地表隆起值减小,地表沉降值增加,且增加量远远大于减小量。 (5)由于超平衡时地表沉降量比欠平衡时小很多,土仓压力易控制在0.15MPa～0.20MPa以内,尽可能的减小地表沉降。所以,在盾构机前方土体不被破坏的前提条件下,适当增加土仓压力是减小地表沉降很有效的措施。 (6)其它条件一定时,地表沉降随着注浆压力的增加而减小。注浆压力易控制在0.15MPa～0.30MPa以内,防止更大的地表沉降发生。
[Abstract]:Shield method has become an important construction method in subway engineering of our country because of its unique characteristics and advantages such as intelligence, safety and rapidity, and has been widely used in underground engineering. However, because the shield construction will inevitably cause land subsidence and deformation, the local surface settlement may endanger the safety of surrounding buildings and underground pipelines, resulting in serious economic losses and social impact. In this paper, the engineering background of the tunnel project between Zhenning Road Station and Outer Ring Road Station (No. 9 Shield Section) of Hangzhou Metro Line 2 is taken as the engineering background. The variation law of ground subsidence caused by shield tunneling construction of subway tunnel is studied by means of case analysis and 3D numerical simulation. The main contents and results are as follows: 1) along the longitudinal shield machine incision, the influence area of shield construction is within 30 m before and within 30 m after the incision of shield machine, and 30 m after the incision of shield machine is the main influence area, and the surface subsidence caused by this range is more than 90%; The area beyond 30 m before and 30 m after the incision of shield machine is not affected or affected can be neglected. 2) the main influence area on the ground surface is about 1 times diameter within 6 m range of the tunnel axis, and 18 m on both sides of the tunnel axis, and 3 times the diameter of the tunnel axis when advancing along the single line of transverse shield tunneling. The main influence area on the surface is 6 m on both sides of the tunnel axis, and 3 times the diameter of the tunnel. 3) the ground deformation caused by shield tunneling is inevitable, and the disturbance of soil in front of shield machine is the important cause of ground subsidence. The disturbance degree of soil in front of shield machine is closely related to the pressure of shield soil bunker. 4) with the increase of the pressure of the soil bunker, the surface uplift of the soil in front of the notch increases continuously, but the increase is very small, and the value of the surface settlement of the soil in the rear decreases continuously, and the decrease is much larger than the increase of the uplift. In the state of overbalance, the surface uplift value increases, the surface subsidence decreases, and the decrease amount is far greater than the increase amount; in the underbalanced state, the surface uplift value decreases, the surface subsidence value increases, and the increase amount is far greater than the decrease amount. 5) because the amount of land surface settlement is much smaller in excess equilibrium than in underbalance, the pressure of soil bunker is easy to be controlled within 0.15MPa~0.20MPa, and the surface subsidence is reduced as much as possible. Therefore, under the premise that the soil in front of shield machine is not destroyed, it is an effective measure to reduce the ground subsidence by increasing the pressure of soil bunker properly. 6) when other conditions are fixed, the surface subsidence decreases with the increase of grouting pressure. Grouting pressure is easy to be controlled within 0.15MPa~0.30MPa to prevent larger surface subsidence.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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