富水长大裂隙对地下洞室施工期围岩稳定影响研究

Study on Influence of Water-Rich Fault on the Stability of Surrounding Rock of Underground Cavern During Construction

江门中微子地下实验室在施工支洞开挖时,揭露三条富水长大裂隙,局部探水孔中出现高压喷射涌水,可能对洞室围岩稳定产生不利影响。为此,采用离散元方法,系统分析了开挖面不同水压力条件下L1、L2、L3对实验大厅围岩变形的影响。结果表明,富水长大裂隙对工程的顶拱围岩整体稳定影响较小,顶拱围岩在L1和L2处对开挖面排水条件变化不敏感,随着开挖面水压升高,L3拱肩部位变形陡增且趋势不收敛。L2对下部水池变形基本无影响,L1、L3附近浅部围岩出现卸荷。综合分析,建议将0.5 MPa作为工程开挖面浅层围岩排水控制标准。

During the excavation of the construction adit,the Jiangmen Neutrino Underground Laboratory revealed three long and water rich cracks,and high-pressure jet water gushing appeared in local water exploration holes,which may have adverse effects on the stability of the surrounding rock of the tunnel.The influence of L1,L2,L3 on the deformation of surrounding rock of the experimental hall under different water pressures of the excavation face was systematically analyzed by using the discrete element method.The results show that the influence of water rich long cracks on the overall stability of the arch surrounding rock is small.The arch surrounding rock at L1 and L2 is not sensitive to the change of the drainage conditions of the excavation face.With the increase of the water pressure of the excavation face,the deformation of L3 arch shoulder increases sharply and the trend is not convergent.L2 has little effect on the deformation of the lower pool,and the shallow surrounding rock near L1 and L3 is obviously unloaded.Based on comprehensive analysis,0.5 MPa is recommended as the control standard for shallow surrounding rock drainage at the excavation face of this project.