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爆破荷载和地应力的瞬态卸载是深埋隧洞开挖损伤区孕育及演化的重要影响因素。根据深埋圆形隧洞爆破开挖过程,采用理论模型和数值模拟相结合的方法分析开挖面上各段爆破引起的爆炸荷载和地应力瞬态卸载应力场的变化规律,并比较各段爆破开挖对隧洞保留岩体的损伤程度。计算结果表明,爆炸荷载对围岩岩体造成的破坏主要是张拉破坏或张剪破坏,地应力瞬态卸载造成的破坏主要是压剪破坏;各段开挖爆炸荷载和地应力瞬态卸载对最终的开挖损伤区均有贡献,体现了重复扰动损伤效应,其中以MS7和MS9段的影响最大,表明各段开挖对最终损伤程度的影响不仅与荷载值的大小有关,与各段的开挖半径同样关系密切;当地应力水平不断提高时,地应力瞬态卸载对损伤区的贡献也会越来越明显;当深埋隧洞开挖的爆破参数相同时,地应力水平将成为围岩损伤的决定性因素。
The transient unloading of blasting load and in-situ stress is an important influential factor in the gestation and evolution of the deep excavation damaged area. According to the blasting excavation process of the deep circular tunnel, the variation law of blasting load and transient unloading stress field caused by blasting in each section of excavation face is analyzed by the combination of theoretical model and numerical simulation. The extent of excavation damage to the rock retaining tunnel. The calculation results show that the damage caused by blast load to surrounding rock mass is mainly tensile failure or shear failure. The damage caused by transient unloading of ground stress is mainly caused by the compression-shear failure. The explosion load and the transient stress relief of each section are unloaded Which will contribute to the final excavation damage area and reflect the repeated disturbance damage effect, of which MS7 and MS9 sections have the most significant impact, indicating that the impact of each section excavation on the final damage degree is not only related to the size of the load value, The same is true for the excavation radius; when the local stress level increases, the contribution of the transient stress relief to the damaged area will become more and more obvious. When the blasting parameters of the deep tunnel excavation are the same, Determinants of rock damage.