Zhou Hongke, Li Hao, Li Anrun, Xie Cong, Wu Shuyu
Power China Guiyang Engineering Corporation Limited, Guiyang, China, 550081, Guizhou.
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, 610059, China.
Sci Rep. 2025 Jan 11;15(1):1733. doi: 10.1038/s41598-025-86253-y.
Aiming at the crucial engineering challenge of the ambiguous excavation deformation mechanism of hard and brittle surrounding rock under high geos-tress conditions, with the right bank diversion tunnel at the dam site of the hydropower station as the research object, the deformation and failure characteristics of the surrounding rock and their formation mechanisms during the layered excavation of the diversion tunnel were investigated. The research findings show: (1) The main factors influencing the deformation of the diversion tunnel's surrounding rock are the high ground stress environment, the degree of fracture development in the rock mass, and the effectiveness of the support system. (2) Following the excavation of the first layer, extensive shallow damage predominates, with damaged blocks primarily exhibiting sheet-like and plate-like forms. After excavating the second and third layers, there is a significant reduction in confining pressure in this region, leading to a rapid deterioration in the extent of damage. (3) Layered excavation induces 'time-dependent' variations in the yield characteristics of the surrounding rock, while simultaneously being influenced by the location and extent of fracture development. The study results are expected to provide a theoretical basis for the excavation of underground caverns under high ground stress.
针对高地应力条件下硬脆性围岩开挖变形机制不明这一关键工程难题，以水电站坝址右岸导流洞为研究对象，研究了导流洞分层开挖过程中围岩的变形破坏特征及其形成机制。研究结果表明：（1）影响导流洞围岩变形的主要因素有高地应力环境、岩体裂隙发育程度和支护系统的有效性。（2）第一层开挖后，以大面积浅部损伤为主，损伤块体主要呈片状和板状。开挖第二、三层后，该区域围压显著降低，损伤范围迅速恶化。（3）分层开挖使围岩屈服特性呈现“时间效应”变化，同时受裂隙发育位置和程度的影响。研究成果有望为高地应力条件下地下洞室开挖提供理论依据。
