"爆破作业，铁路综合工程，公路工程，房屋建筑工程，机场场道工程，水利水电工程，机械修理、加工、制造，钢结构工程，机电设备安装，土石方工程，市政公用工程，矿山工程，环保工程，城市及道路照明工程，消防设施工程，防水防腐保温工程，桥梁预制，各类混凝土预制，地基与基础工程的施工,工程试验、检测，工程物资销售，物业管理，转供水电，动产及不动产租赁服务，混凝土的生产与销售，工程测量，研发服务；员工培训（内部），会议服务（内部）。（依法须经批准的项目，经相关部门批准后方可开展经营活动） "
The section between Wangjiacheng Station and Shengjipu Station of Chongqing Line 4 needs to pass through 3 sections of newly filled soil-rock mixture.Due to the loose structure,poor uniformity,large voids,insufficient consolidation and low shear strength of the newly filled soil-rock mixture,tunnel construction is prone to cause significant ground settlement.The applicability and construction technology of compound TBM in soil-rock mixture backfill area are summarized in this paper.The results show that:Pre-reinforcement via surface sleeve-valve grouting(pressure:0.1～0.3 MPa)enhances soil strength(unconfined compressive strength ≥ 1.2 MPa)and density(shear wave velocity ≥ 300 m/s);"Low penetration+high rotation"mode(advance rate≤30 mm/min,cutterhead rotation 0.8～1.0 r/min)with strict control of muck discharge(72.46 m3/ring)and synchronous grouting volume(6.66～11.1 m3/ring)is adopted;Large boulders(≤300 mm)are fragmented by hydraulic splitting.Numerical analysis identified backfill depth and grouting range as dominant settlement factors and the area for surface pre-grouting reinforcement is suggested to expand to the sides of the arch rib by 1.0D.The measurement results show that this technology has controlled the surface subsidence to 24 mm(below the warning value of 30 mm),and the subsidence of the tunnel arch top and the net clearance convergence are below the design limits.
