深切河谷区水电站厂址初始应力场规律研究及对地下厂房布置的思考  

INITIAL 3D GEOSTRESS FIELD RECOGNITION OF HIGH GEOSTRESS FIELD AT DEEP VALLEY REGION AND CONSIDERATIONS ON UNDERGROUND POWERHOUSE LAYOUT

作　　者：黄书岭[1] 丁秀丽[1] 廖成刚[2] 邬爱清[1] 尹健民[1] 

机构地区：[1]长江科学院水利部岩土力学与工程重点实验室,湖北武汉430010 [2]中国电建集团成都勘测设计研究院有限公司,四川成都610072

出　　处：《岩石力学与工程学报》2014年第11期2210-2224,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51379022;51179013);国家重点基础研究发展计划(973)项目(2011CB710603)

摘　　要：针对深切河谷高地应力区水电站厂址区域初始地应力张量空间分布特征及其与洞室群布置相对关系识别问题,结合河谷历史发展过程分析、应力张量空间解析法和多核并行计算技术等,将复杂地质环境下三维地应力场模型与洞室群精细开挖计算模型相耦合,提出考虑河谷演化规律的厂址区域地应力场量化精细数值模型的建立方法和分析思路,识别锦屏一级水电站厂址区初始应力场分布规律并进行现场验证,结果表明：锦屏一级地下厂房洞室群位于深切河谷附近应力变化较大且应力水平相对较高的应力过渡区,由此形成初始高地应力环境,且主应力比为1.9-2.5,岩石强度应力比为1.5-3.0;在这种高地应力–低强度应力比且高主应力比共同作用下,地下厂房洞室群施工期围岩出现的变形破坏规律及卸荷松弛深度超过同等规模的地下厂房工程,而现场围岩应力诱导型变形破坏的发生位置和分布规律,则佐证了所获得的厂址初始应力场的合理性,同时也验证了地应力场量化模型建立方法的科学性和可行性。在此基础上,建立一种考虑三维地应力、岩石强度应力比和岩体结构特征的高地应力区地下厂房洞室群结构布置设计方法,其本质上体现洞室荷载特征（三维地应力,包括最大主应力量值和方位,而且还考虑地应力场分布、主应力比等）、围岩结构特征及承载能力（岩石强度）等因素的协同耦合作用,并从定性角度建议确定主洞室位置、纵轴线、间距和洞型等一些原则和思路。In order to understand the spatial distribution of stress tensors of initial geostress field and to identify its relationship with the cavern group arrangement for hydropower plant site in high geostress region of deep valley,a new method and an operation procedure for obtaining a quantitative and fine numerical initial geostress field based on the coupling of 3D initial geostress calculation model and the structural calculation model containing excavation details were proposed considering the evolution process of river valley,using the space analysis method of stress tensor and the multi-core parallel computing technique. Then,the initial geostress field distribution at Jinping I hydropower station was identified with the method and verified against the field phenomenon of deformation and failure. The underground cavern groups of Jinping I hydropower station were found to be in the stress transitional region near the deep valley with the high geostress levels and the large stress variations and the high initial geostress environment was thus formed. The average principal stress ratio is about 1.9–2.5 and the rock strength-stress ratio is about 1.5–3.0 in this transitional region. Under the high initial 3D geostress,the low strength-stress ratio and the high principal stress ratio,the deformation and the failure and the depth of unloading relaxation of the surrounding rock during the construction of the underground powerhouse cavern groups were found to be larger than the ones of the cavern groups of the same size in other projects. The locations and distributions of the stress induced deformation and failure confirm the reasonability of the initial 3D geostress field obtained and also verify that the above proposed quantitative model of geostress field is correct and feasible. On this basis,a method of layout design for the underground powerhouse cavern groups located in high geostress area was proposed,considering the three-dimensional geostress,the strength to stress ratio and the structure characteristic,

关 键 词：岩石力学 锦屏一级水电站 地下厂房洞室群 地应力场量化模型 高地应力 

分 类 号：TU45[建筑科学—岩土工程]