针对复杂洞库群工程施工隧道多、通风竖井多、工作面多、交叉口多等难题,以“818项目”为依托,研究了复杂洞库群快速施工方法与支护技术。提出了五线并行小间距浅埋特大断面隧道群施工方法,优化了单一隧道施工四台阶工法。数值分析与现场监测数据表明:五线并行特大断面隧道群同步施工围岩垂直应力增大,拱顶应力减小,地表沉降与围岩变形在控制范围内,围岩稳定性系数为0.882,需及时和加强初期支护;优化了隧道交叉口马头门破除钢拱架和超前小导管参数,保障了横向联络隧道与特大断面隧道交叉口施工安全;通过隧道断面尺寸、围岩压力、围岩岩性与力学性质,优化了初期支护参数,支护效果良好。研究成果进一步丰富了复杂洞库群施工方法与支护技术。

Aimed at the complex cave and reservoir group project construction tunnels, ventilation shafts, working surfaces, intersections and other difficult problems, based on the “818 Project”, the rapid construction methods and support technologies for complex cave groups have been studied. A construction method for five parallel tunnels with small spacing and shallow burial of super-large cross-section was proposed, optimizing the four-step construction method for single tunnels. Numerical analysis and field monitoring data show that synchronous construction of five parallel super-large cross-section tunnels increases the vertical stress of surrounding rock while reducing the vault stress. Surface settlement and surrounding rock deformation are within the control range, with the surrounding rock stability coefficient being 0.882, requiring timely and strengthened initial support. The parameters of steel arch removal and advanced small pipe were optimized at tunnel intersection portals to ensure construction safety at intersections between lateral connection tunnels and super-large cross-section tunnels. By considering tunnel cross-section size, surrounding rock pressure, lithology, and mechanical properties of surrounding rock, initial support parameters were optimized, resulting in good support effects. The research findings further enrich construction methods and support technologies for complex tunnel groups.