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由于地下工程处于一定水平的地应力环境中,块体边界法向应力概化的正确与否直接关系到块体的稳定性分析结果,现通过实测途径确定块体边界法向应力的研究还较少。基于大型地下厂房块体稳定性分析,通过在块体范围及邻区不同方向布置多个钻孔,首次将原生裂隙重张试验引入到块体边界法向应力的测定,对开挖后与块体主要边界产状相近的所有原生裂隙的法向应力进行了测试,成功取得了块体边界上的法向应力状态及其空间变化规律。研究结果表明:洞室开挖完成后,块体边界应力分布不均匀,但具一定规律,垂直向表现为从浅部到深部结构面的法向应力依次增大,在水平向上,随与洞室开挖面距离的增大而增大;结构面的法向应力实测值稍小于基于围岩应力的估算值,但总体一致。该成果可为确定围岩块体的边界力学状态和应力模型简化提供参考和依据。
Because the underground engineering is in a certain level of stress environment, the normalization of the normal stress of the block boundary is directly related to the stability analysis results of the block. less. Based on the analysis of the stability of large-scale underground powerhouse blocks, through the arrangement of multiple boreholes in different blocks and adjacent areas, the first time the original fracture re-tension test was introduced to the determination of the normal stress of the block boundary. After excavation and block The normal stresses of all the primary cracks near the main boundary of the body are tested and the normal stress state and its spatial variation on the boundary of the block are successfully obtained. The results show that the stress distribution of block boundaries is not uniform after the completion of tunnel excavation, but with the regularity, the normal stress increases from shallow to deep in the order of increasing in the vertical direction, The excavation surface increases with the increase of distance; the measured value of normal stress of structure surface is slightly less than the estimate based on the stress of surrounding rock, but it is generally the same. The results can provide reference and basis for determining the boundary mechanical state and stress model simplification of surrounding rock mass.