Peng Feng, Yuan Xiqiang, Li Tianbin, Yuan Yang, Ma Chunchi, Yang Ping, Luo Hong, Deng Changzhong
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China.
College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu, China.
Sci Rep. 2025 Feb 22;15(1):6445. doi: 10.1038/s41598-025-90364-x.
The scope of the surrounding rock loosening and its mechanical properties can significantly affect the analysis of the excavation loosening range, stress-strain state partitioning, and surrounding rock mass stability. Investigating the mechanical properties and failure modes of the surrounding rock mass is of significant engineering value for optimizing support design and ensuring the safety of tunnel construction and. Therefore, the tests on loose circle and mechanical properties of the rock mass were conducted, yielding the following results. (1) The sonic wave testing method and ground penetrating radar (GPR) detection were more suitable for loose circle testing of extremely thin-layered phyllite than the True Reflection Tomography (TRT) method and borehole camera method. (2) The loose circle ranges for the test sections were 4.9 m and 6.8 m, respectively. (3) The cohesion and internal friction angle of the test sections were less than 0.3276 MPa and 19.0°, respectively. The test results were consistent with the predominant phyllite composition of the surrounding rock. This study combined in situ tests and site conditions to analyze the causes of tunnel deformation and instability, offering recommendations for tunnel support. These findings served as valuable guidance for similar tunnel support design and construction, and play a crucial role in ensuring constructor safety.
围岩松动范围及其力学性质会对开挖松动范围分析、应力应变状态划分以及围岩稳定性产生显著影响。研究围岩的力学性质和破坏模式对于优化支护设计以及确保隧道施工安全具有重要的工程价值。因此，开展了岩体松动圈及力学性质试验，得到以下结果：（1）与真反射层析成像（TRT）法和钻孔摄像法相比，声波测试法和探地雷达（GPR）探测更适合极薄层状千枚岩的松动圈测试。（2）试验段的松动圈范围分别为4.9米和6.8米。（3）试验段的黏聚力和内摩擦角分别小于0.3276兆帕和19.0°。试验结果与围岩主要由千枚岩组成的情况相符。本研究结合现场试验和现场条件分析了隧道变形和失稳的原因，为隧道支护提供了建议。这些发现为类似隧道支护设计和施工提供了有价值的指导，对确保施工人员安全起着至关重要的作用。
