乌东德水电站地下厂房层状节理岩体稳定性研究

发布时间：2018-08-07 19:18

【摘要】：随着中国水电资源开发的推进,越来越多水电站修建于高山峡谷之中,受地形地貌的影响,大量水电站厂房布置于层状岩体之中,定量分析层状节理岩体地下厂房变形并评价其稳定性成为亟需解决的重要课题。本文结合现场监测及数值模拟结果,分析不同密度层状岩体对于地下厂房变形的影响。对多点位移计、声波测试、微震监测等多种监测结果进行整理和归纳,从多角度揭示围岩变形规律及内部损伤情况。另外基于厂区工程地质特性、地应力实测资料,利用通用离散元程序UDEC对7~#机组典型剖面进行数值分析,得到地下厂房开挖后的应力场、塑性区、位移场分布规律,揭示围岩潜在破坏区域。数值模拟与微震监测结果共同表明:围岩第Ⅵ层(高程815.40~809.00 m)开挖时,上游边墙812 m高程位移增加最快,微震事件数量大幅增长。水平向应力卸荷程度大于竖向应力卸荷程度;整体上主厂房上游侧位移大于下游侧,最大变形出现在上游边墙812 m高程附近,此处围岩屈服深度最大,围岩屈服集中区域与变形场分布基本一致,上游层状节理比下游密集是造成上下游变形差异的主要原因。围岩变形与层状节理分布关系密切,开挖活动将引起围岩层状节理活化、岩体损伤、围岩整体强度降低。开挖强度越大,微震事件增加越快,变形越大。乌东德地下厂房变形机制的研究对其后续施工及其安全运营具有重要意义。
[Abstract]:With the development of hydropower resources in China, more and more hydropower stations are built in high mountains and canyons. Due to the influence of topography and landform, a large number of hydropower plants are arranged in layered rock mass. It is an important task to analyze quantitatively the deformation of layered jointed rock underground powerhouse and to evaluate its stability. Combined with field monitoring and numerical simulation results, the effect of layered rock mass with different densities on deformation of underground powerhouse is analyzed in this paper. The monitoring results of multi-point displacement meter, acoustic wave test and microseismic monitoring are summarized, and the deformation law and internal damage of surrounding rock are revealed from many angles. In addition, based on the engineering geological characteristics of the plant area and the measured data of in-situ stress, the numerical analysis of typical section of No. 7 unit is carried out by using the general discrete element program UDEC, and the distribution of stress field, plastic zone and displacement field after excavation of underground powerhouse is obtained. The potential damage area of surrounding rock is revealed. The results of numerical simulation and microseismic monitoring show that the displacement of 812 m elevation of the upstream sidewall increases fastest and the number of microseismic events increases significantly when the sixth layer of surrounding rock (815.40 ~ 809.00 m) is excavated. The horizontal stress unloading degree is greater than the vertical stress unloading degree, the upstream displacement of the main powerhouse is larger than the downstream side, and the maximum deformation occurs near the 812 m elevation of the upstream side wall, where the yield depth of the surrounding rock is the largest. The yield concentration area of surrounding rock is basically consistent with the distribution of deformation field, and the density of upstream layer joint ratio is the main reason for the deformation difference between upper and lower reaches. The deformation of surrounding rock is closely related to the distribution of layered joints. Excavation will lead to the activation of layered joints of surrounding rocks, the damage of rock mass and the decrease of the overall strength of surrounding rocks. The greater the excavation intensity, the faster the increase of microseismic events and the greater the deformation. The study of deformation mechanism of underground powerhouse in Udongde is of great significance for its subsequent construction and safe operation.
【作者单位】：四川大学水力学与山区河流开发保护国家重点实验室;中国长江三峡集团公司;
【基金】：国家重点基础研究发展计划资助项目(2015CB057903) 国家自然科学基金面上项目资助(51374149)
【分类号】：TV731.6

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