水下盾构隧道的合理覆土厚度数值模拟分析  

Numerical Simulation Analysis of Reasonable Overburden Depth of Underwater Shield Tunnel

作　　者：郭彩霞 王梦恕[2] 孔恒 史磊磊[4] 

机构地区：[1]清华大学土木工程安全与耐久教育部重点实验室,北京100084 [2]北京交通大学城市地下工程教育部重点实验室,北京100044 [3]北京市政建设集团有限责任公司,北京100089 [4]北京市市政四建设工程有限责任公司,北京100176

出　　处：《中国公路学报》2017年第8期238-246,共9页China Journal of Highway and Transport

基　　金：国家重大研发计划项目(2017YFC0805008)

摘　　要：针对水下隧道长期赋存于富水环境中,围岩的力学性质较差,地层的成拱能力降低的特点,研究水下盾构隧道的合理覆土厚度,为设计与施工提供参考。在国内外学者研究成果的基础上,依托具体的工程实例,鉴于实际施工中盾尾管片壁后注浆对盾构隧道的动态上浮作用和对地层沉降的影响,进而确定对盾构隧道最小覆土厚度的影响,同时基于水下隧道突水风险研究,综合考虑水、土、注浆浆液的动态影响,通过对颗粒流数值模拟结果进行分析,给出水下盾构隧道合理覆土厚度和最小覆土厚度临界值的判定依据和条件,采取必要的信息化施工和响应联动措施,控制水下盾构隧道浅覆土穿越水体地层变位,保证工程和环境的安全。研究结果表明:双洞隧道的地表沉降曲线基本符合Peck沉降槽理论,随着埋深的增加,地表沉降将由2个独立的沉降槽逐渐发展叠加为1个新的沉降槽;对于依托工程而言,隧道覆土厚度的临界值为1.3D;围岩的竖向位移随距隧道中心线距离的增大而减小,当距离增大到0.5D后位移变化不再显著;隧道开挖后,由于隧道顶部土体拱效应的发挥,不同埋深情况下作用在管片上的土压力将明显小于初始土压力,且压力值与埋深成正比。Aimed at poor mechanical properties of surrounding rock for underwater tunnel and decreased arching ability of underwater shield tunnel in the water-rich environment for a long time,the reasonable overburden depth of underwater shield tunnel was investigated to provide a reference for design and construction.Based on the domestic and foreign scholars＇ research results,the influence on the minimum overburden depth of shield tunnel was determined by a specific engineering project,in view of the effect of shield tail after grouting on dynamic float and settlement of stratum.Whilst the dynamic effects of water,soil and grouting slurry was takeninto consideration by dint of the water inrush risk investigation of the underwater tunnel.The numerical simulation of the particle flow was analyzed and judgement basis and conditions for critical values of reasonable overburden depth and the minimum overburden depth of underwater shield tunnel was offered.The necessary information construction and response linkage measures was deployed to control the stratum deformation caused by shallow overburden through the wave to ensure the safety of the engineering and the environment.The results show that the surface subsidence curve of the double-hole tunnel is basically in accordance with the Peck＇s theory.With the increase of the buried depth,the surface subsidence gradually develops from two independent subsidence troughs to a new subsidence trough.The critical value of overburden of the shield tunnel is 1.3D for the engineering case.The vertical displacement of the surrounding rock decreases with the increase of distance from the centerline of the tunnel,but the change is not significant when the distance increases to 0.5D.After the tunnel excavation,the pressure acting on the segment is much less than the initial earth pressure in different conditions of buried depth on account of the arching effect at the top of the tunnel.Whilst the pressure is proportional to the buried depth.

关 键 词：盾构隧道 水下隧道 数值模拟 颗粒流 合理覆土厚度 

分 类 号：U455.46[建筑科学—桥梁与隧道工程]