乌东德水电站地下厂房主要工程地质问题研究

Study on engineering geological problems of underground powerhouses of Wudongde Hydropower Station

乌东德水电站两岸地下厂房位于坚硬的中厚层陡倾角灰岩及白云岩内,具有"大跨度、高边墙、中厚层、陡倾角、低地应力、小夹角"的工程特点,归纳总结开挖揭露出的工程地质问题有8类:即层面走向与厂房轴线夹角小所引起的高边墙变形稳定问题;块体问题;B类角砾岩因抗压强度与变形模量相对较低存在的围岩变形稳定问题;层面附碳质薄膜区因岩体完整性差而存在的变形稳定问题;顶拱零星分布的较长大缓倾角裂隙所引起的块体问题;零星分布的短小缓倾角裂隙较发育区顶拱局部变形或掉块问题;走向与厂房轴线夹角小且性状较差的断层或长大裂隙所引起的局部边墙变形稳定问题;溶洞问题。对各类工程地质问题的特点进行归纳总结,可为设计采取针对性的处理措施奠定坚实的地质基础。

Since the powerhouses of Wudongde Hydropower Station are located in hard medium - bedded limestone and dolo- mite with a high dip, the following engineering geological characteristics can be found： long span, high side walls, medium bed with a deep angle, low geostatic stress and a low included angle. During the excavation~ eight engineering geological problems are revealed and summarized, including： deformation and instability of the high side walls caused by the low included angle between the strike line of the rock bed and the axis of the powerhouses; instability of the surrounding rock caused by relatively low com- pressive strength and deformation modulus of the Class B breccia; deformation and instability of the carbonaceous membrane zone on the top of the bed caused by the low integrity of the rock; instability of the blocks over the vault of the powerhouses caused by the long and large low - angle fissures ; deformation and chipping of some parts of the vault caused by the short and small low an- gle fissure zone; deformation and instability of some parts of the side walls caused by the low included angle as well as the long and large fissures; the karst cave problem. According to these problems, targeted countermeasures can be adopted in the design phase of the project.