深埋软岩公路隧道大变形段双层支护方案研究 (3)（论文）.pdf

· 83· 深埋软岩公路隧道大变形段双层支护方案研究柴琦龙（中铁十五局集团第四工程有限公司，郑州 450000）　　［摘　要］根据云南省云临高速公路大亮山隧道穿越复杂地质条件时出现的初期支护开裂、仰拱隆起等灾害，单层初期支护无法抵抗围岩压力，采用双层初期支护进行优化设计。利用有限差分数值模拟软件对单层初期支护与双层初期支护开挖后围岩与支护结构力学响应进行对比，并与现场监测数据对比分析。研究结果表明：单层初期支护拱顶沉降、仰拱隆起、二次衬砌内力、塑性区半径均大于双层初期支护，采用双层初期支护可以保障隧道安全掘进；针对隧道拱顶沉降与仰拱隆起变形曲线，建议采用扩大拱脚、尽早施作仰拱、增设锁脚锚杆等措施控制隧道的变形、开裂等灾害。　　［关键词］挤压隧道；软岩大变形；数值模拟；双层初期支护　　［中图分类号］ U 455.7 　　　　［文献标志码］ A　　　　　［文章编号］ 1001 -523X （2023 ）07-0083 -05 RESEARCH ON DOUBLE-LAYER SUPPORT SCHEME IN LARGE DEFORMATION SECTION OF DEEP-BURIED SOFT ROCK HIGHWAY TUNNEL Chai Qi-long 　　［Abstract ］ In this paper, according to the disasters such as initial branch cracking and inverted arch uplift occurred when the Daliangshan Tunnel of Yunlin Expressway in Yunnan Province passes through complex geological conditions, the single-layer initial support cannot resist the surrounding rock pressure, and the double- layer initial support is used to optimize the design. The ﬁnite diﬀerence numerical simulation software was used to compare the mechanical responses of the surrounding rock and the supporting structure after the excavation of the single-layer initial support and the double-layer initial support, and compared with the ﬁeld monitoring data. The research results show that the single-layer primary support vault settlement, inverted arch uplift, lining internal force, and plastic zone radius are all larger than those of the double-layer primary support. For the deformation curve of the arch uplift, it is recommended to take measures such as enlarging the arch feet, applying the inverted arch as soon as possible, and adding locking anchors to control the deformation and cracking of the tunnel. 　　［Keywords ］ extrusion tunnel; large deformation of soft rock; numerical simulation; double-layer initial support 软弱围岩隧道大变形灾害一直是困扰隧道工程界的难题。千枚岩、泥灰岩、砂质泥岩等软弱围岩强度低、节理发育密集和遇水软化易崩解的特性使得隧道穿越该种地质条件时极易出现初期支护侵限、钢拱架扭曲、混凝土开裂与围岩垮塌等问题，对施工安全带来很大危害性，许多工程案例均证明这一点。武都西隧道穿越大变形段时出现拱架扭曲变形，初期支护表面混凝土开裂、掉块等问题。云屯堡隧道由于围岩水平应力过大，导致施工过程中混凝土掉块、大面积初期支护侵限灾害时有发生。兰渝铁路两水隧道由于最大水平主应力达到11. 3 MPa ，施工时原有支护结构难以抵抗围岩压力，拆拱换拱后仍无法抑制二次衬砌开裂，严重影响了工期 [5]。为了有效控制这类挤压大变形问题，众多学者进行了相应的研究，提出了多重支护、可让压支护和联合支护等多种支护方案。其中双层支护作为一种有效的手段，在许多工程中得到应用。李

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