Analysis on Backfilling Construction Technology of Enlarging the Tunnel Chamber of Diversion Tunnel Constructed by TBM in the “Project of Transferring Water from Hongyan River to Shitou River”
Water resources and hydropower engineering is the main part of infrastructure in China, which is closely related to the social and economic development. Weak rock stratum is one of the most common and harmful phenomena in tunnel excavation. Targeted measures must be taken based on the different conditions of tunnel strata. At present, the technology that can prevent and deal with this kind of rock stratum by using advanced small pipes and large pipe sheds in tunnel construction has been quite mature at home and abroad. By applying large pipe sheds in advance to enlarge the tunnel chamber of diversion tunnel in the “Project of Transferring Water from Hongyan River to Shitou River, TBM is greatly improved to pass through the bad geological section. However, when the cavity of a water tunnel that is constructed by small-diameter double-shield TBM is backfilled, large equipment can’t be used, which not only increases the difficulty of tunnel construction but also greatly delays the project schedule. According to the specific engineering background and construction demand, the application of cavity backfilling technology of the small-diameter tunnel in water conservancy and hydropower projects can effectively avoid both all kinds of potential safety hazards in the construction of specific projects and negative influences of the external environment on the construction of the hydraulic engineering. Moreover, it can fundamentally solve various problems in the construction of the water conservancy and hydropower projects and give full play to its utilization performance, which will eventually ensure the benefit of the construction itself and people.