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库尉输水隧洞前段位于库鲁克山北侧倾斜砾质平原区,地下水位埋深较浅(最浅处仅为1.4 m),且远高于设计洞顶,给设计和施工带来了巨大的困难和挑战。在深入分析水文地质条件的基础上,采用大型有限差分软件FLAC3D对3个典型断面进行了流固耦合分析。研究表明,地下水对隧洞受力及变形特性影响显著,耦合条件下低液限粉土洞段拱顶变形约为不考虑渗流影响时的5.6倍,且与实测值更为接近;不同围岩类型和水文地质条件下各洞段的变形差异较大,耦合条件下低液限粉土洞段的拱顶变形为90 mm、而粉土夹砂和粉细砂夹砾石洞段的变形分别为36 mm和26 mm;耦合条件下各典型断面支护结构受力均超过了素喷混凝土的设计抗拉强度(1.1 MPa),需尽快施做二次衬砌。以上研究成果可为本工程及类似工程的设计与施工提供参考。
The front of Kuweow water conveyance tunnel is located in the inclined gravel plain on the northern side of Kurok Mountain, with a shallow groundwater depth (only 1.4 m at the shallowest point) and much higher than that of the design culvert, which brought about the design and construction Huge difficulties and challenges. Based on the in-depth analysis of hydrogeological conditions, a large-scale finite difference software FLAC3D was used to analyze the three typical cross-sections. The results show that underground water has a significant influence on the stress and deformation characteristics of the tunnel. Under the condition of coupling, the deformation of the vault in the low liquid limit silt cave section is about 5.6 times of that without considering the influence of seepage, and it is closer to the measured value. And the deformation of each section under hydrogeological conditions are quite different. The deformation of the vault in the low liquid-limit silt section under coupling conditions is 90 mm, while the deformation of silt sand and silty sand folder gravel sections is 36 mm and 26 mm respectively. The stress of each typical section supporting structure under the coupling condition exceeded the designed tensile strength (1.1 MPa) of the plain shotcrete. The secondary lining should be applied as soon as possible. The above research results can provide reference for the design and construction of this project and similar projects.