【摘要】 重庆4号线王家城站—生基堡站区间需穿越3段新近块石回填土地层，由于新近块石回填土地层结构松散、均匀性差、空隙大、欠固结以及抗剪强度低，隧道施工易引起较大地表沉降。本文对回填土区复合式TBM的适用性和施工技术进行了总结。结果表明：通过地表袖阀管注浆预加固(压力0.1～0.3 MPa),提升土体强度(无侧限抗压强度≥1.2 MPa)与密实度(剪切波速≥300 m/s);掘进中采用"小贯入度+高转速"模式(速度≤30 mm/min,转速0.8～1.0 r/min),严格控制出土量(72.46 m~3/环)与同步注浆量(6.66～11.1 m~3/环);对大粒径孤石实施液压分裂破碎(≤300 mm)。数值分析揭示填土深度与注浆范围为块石回填土区地表沉降主控因素，建议地表预注浆加固范围扩大至拱腰两侧1.0D。实测表明，该技术将地表沉降控制在24 mm(低于预警值30 mm),隧道拱顶沉降与净空收敛小于设计限值。更多还原

【Abstract】 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 m~3/ring) and synchronous grouting volume(6.66～11.1 m~3/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.更多还原