山区隧道穿越煤系地层开挖方法适用性数值分析

作者：李怀友¹,李献民¹’²,孙新海¹’³,汪微¹’³

作者简介：

李怀友，高级工程师，E⁃mail:110457838@ qq. com

作者单位：

1.中交一公局集团有限公司，北京 100024; 2.中南大学地球科学与信息物理学院，湖南长沙 410083; 3.重庆中交渝武高速公路有限公司，重庆 401520

基金项目：

∗中交一公局集团科技研发项目（KJYF⁃2021⁃B⁃14,YGJKT⁃2019⁃B⁃04）

摘要：

山区矿产丰富、煤层破碎，隧道穿越煤系地层施工时，围岩变形控制困难，施工扰动易致使隧道拱顶坍塌及支护结构破坏。依托某隧道工程，开展隧道穿越煤系地层施工力学特性的数值仿真研究，对比分析了采用全断面开挖法、台阶法和预留核心土法等不同工法在煤系地层隧道施工中其受力变形特征，并对不同工法的适用性进行了研究。研究结果表明，3 种工法均会产生拱顶沉降，预留核心土法产生拱顶沉降和水平位移最小分别为~9.06,2.26mm,全断面开挖法拱顶沉降和水平位移最大分别为~15.28,14.88mm.全断面开挖法由于衬砌整体性好，可有效减小拱顶应力集中，缓解支护结构的偏心受压程度；而预留核心土法和台阶法拱顶出现明显应力集中，支护结构左侧受拉、右侧受压。从整体施工分析，全断面开挖法在施工初期拱顶沉降迅速增加，衬砌闭环后趋于稳定；而台阶法在上台阶开挖时拱顶沉降较大，处于高风险期。预留核心土法虽开挖步较多，但可较好地控制煤层围岩变形，在煤系地层施工中具有较强适用性。

关键词：隧道；煤系地层；开挖；数值模拟；力学特性

English：

Mountain areas are rich in mineral resources, and coal seams are fragmented. Constructingtunnels crossing coal measure strata, it is difficult to control the deformation of the surrounding rock.Construction disturbances can easily cause collapse of the tunnel arch and damage to the supportstructure. Based on a tunnel project, numerical simulation research on the mechanical characteristics oftunnel construction crossing coal measure strata was carried out. Different construction methods such asfull⁃face tunneling method, bench cut method, reserved core soil method were compared and analyzed fortheir stress and deformation characteristics in tunnel construction crossing coal measure strata. Theadaptability of different construction methods was discussed. The research results show that all threeconstruction methods will cause uneven settlement of the arch crown. The minimum settlement of the archcrown caused by the reserved core soil method is -9.06mm, and the minimum horizontal displacement is2.26mm. The maximum settlement and horizontal displacement of the arch crown caused by full⁃facetunneling method are - 15.28mm and 14.88mm respectively. Due to the good overall integrity of thelining, full⁃face tunneling method can effectively reduce the stress concentration on the arch crown andalleviate the degree of eccentric compression of the support structure. However, reserved core soil method and bench cut method have obvious stress concentration on the arch crown, causing tension on the leftside of the support structure and compression on the right side. From the overall construction analysis,full⁃face tunneling method rapidly increases the settlement of the arch crown in the early stage ofconstruction, and tends to stabilize after the lining is closed loop,while bench cut method has a largesettlement of the arch crown during the excavation of the upper platform,which is in a high⁃risk period.Although reserved core soil method involves more excavation steps, it can effectively control thedeformation of coal seam surrounding rock and has strong adaptability in tunnel construction crossing coalmeasure strata.

基础设施 > 2025年 第卷 第24期