大凉山1号软岩隧道变形控制方案设计

Design of Deformation Control Scheme for Daliangshan No. 1 Soft Rock Tunnel

摘要: 以四川省大凉山1号平导洞隧道工程为背景，针对软岩的流变性造成隧道结构不稳定、变形量大的问题，设计隧道初支护系统。通过对喷射混凝土、锚杆、H型钢拱架提供的支护抗力和围岩自承力进行计算，利用剪切滑移破坏法对喷射混凝土强度及厚度、钢筋网型号及间距、锚杆型号及间距、H型钢拱架型号及间距进行计算与选型。在满足预留变形量小于5 cm的条件下，选用型号尺寸相对较小的支护材料，对于该工程中完整性较差的V级围岩采用C25强度混凝土、HW150工字钢和φ22药卷锚杆。其他支撑能力较好的围岩中分别采用型号和强度较小的支护材料，在保障施工安全的同时节约隧道中的空间成本以及施工成本。使用有限元软件ABAQUS对隧道围岩支护结构进行仿真分析，仿真结果表明，应力与位移场仿真结果与计算结果相比差异较小，证明理论计算准确性高，为建立软弱围岩大变形下的科学支护理论提供了思路。

Abstract: Based on the TBM tunnel project of Daliangshan No. 1 pilot tunnel in Sichuan Province, aiming at the problem of large tunnel deformation in soft rock, the primary support system of TBM tunnel is designed. Through the calculation of the support resistance provided by shotcrete, anchor rod and H-shaped steel arch and the self-supporting force of surrounding rock, the shear slip failure method is used to calculate and select the strength and thickness of shotcrete, the model and spacing of reinforcement mesh, the type and spacing of anchor rod and the model and spacing of H-shaped steel arch. Under the condition that the reserved deformation is less than 5cm, the support materials with relatively small model and size shall be selected. For class V surrounding rock with poor integrity in the project, C25 strength concrete, HW150 I-steel and φ22 cartridge bolt are used. In other surrounding rocks with better support capacity, the support materials with smaller model and strength are used respectively, which can save the space cost and construction cost in the tunnel while ensuring the construction safety. It provides an idea for the design of TBM tunnel support system under large deformation of soft surrounding rock.