【作者】 李攀峰；

【导师】 张倬元；

【作者基本信息】 成都理工大学 ， 地质工程， 2004， 博士

【摘要】 随着西部大开发战略的实施，西部高山峡谷地区所蕴藏的丰富水能资源开发进入了新的高峰期。受地形条件的限制，开发这些地区的水能资源往往需要布置大规模的地下厂房洞室群。规模庞大、空间组成复杂的洞室群布置在有限的地下空间内，其开挖效应以及不同洞室之间的相互影响，将关系到整个水电站工程的建设成本和运营效益，因此是一个值得深入研究的问题。 基于此，本论文以黄河拉西瓦水电站地下厂房洞室群为例，从工程地质学的角度对与大型地下洞室群围岩稳定性密切相关的问题进行了较为全面的分析与评价。主要内容包括：①在野外地质调查基础上，通过统计分析得到地下厂区结构面的优势方位；对结构面工程地质特性进行了分析；根据结构面的空间组合关系，搜索出可能在主厂房洞室的顶拱和边墙部位出露的块体，并分析了各块体的可能滑移方式及其稳定性系数。②基于勘探平硐获取的资料，运用“围岩工程地质分类法”、BQ法、RMR法和Q系统法进行了地下厂区岩体质量评价；讨论了四种不同方法评价结果之间的相关性。③根据简易推断法、地震震源机制分析法以及地应力实测资料统计分析结果，综合确定了工程区的主压应力方向；运用地质宏观判断法并结合地应力实测资料的统计分析结果对地应力的量级进行了综合评价，并进一步讨论了黄河快速下切对研究区地应力场的影响；运用有限元法模拟了研究区地应力场的形成过程，并探讨了地应力的空间分布规律。④分析了洞室形状、洞室规模、地应力因素对单个洞室开挖效应的影响：分析了洞室间距、岩体质量、开挖顺序等因素对复式洞室开挖效应的影响；讨论了拉西瓦地下洞室群群洞效应的具体规律。⑤选取岩体质量、开挖效应、群洞效应以及次生灾害效应作为指标，建立了“大型地下洞室群围岩稳定性分类”方案；运用该方案对拉西瓦水电站主厂房洞室进行了稳定性评价。 在完成上述工作的过程中，本论文主要在以下几个方面进行了一些探索： ①基于空间解析几何原理，提出了块体搜索的基本思路并编制出相应的程序，基本实现了块体搜索的自动化，既大大缩短了块体搜索时间，又能防止因人工搜索引起的遗漏； ②推导出Ⅱ-2型(单滑面滑动，但受侧限面约束)块体的稳定性系数计算公式； ③以数值模拟方法论证了拉西瓦地下厂房洞室群全断面一次开挖时群洞效应的具体特点； ④以岩体质量、开挖效应、群洞效应和次生灾害效应为评价指标，建立了“大型地下洞室群围岩稳定性分类”方案；该方案既继承了水电行业规范“围岩工程地质分类”法的优点，又综合考虑了大型地下洞室群的工程特点。更多还原

【Abstract】 With the great development of West China, a new prosperous period of water power exploitation in the rugged mountainous area of Western China, where is rich in hydroelectric resources, is coming. It is usually needed to construct large scale underground projects for water power utilization in this area. Under these circumstances, the underground caverns with characteristics of large scale and complex spatial arrangement are located close in finite underground space. Thus the excavation effect and the interaction among different caverns during the process of underground projects construction are needed to be studied thoroughly which affect the cost of construction and production of power station.So taking the underground caverns of Laxiwa hydroelectric power station on Yellow River as an example, some problems closely related to the stability of rock mass surrounding underground caverns were analyzed in detail from the engineering geologic points of view. And the main contents of this dissertation are: (1)The engineering geological features of discontinuities in surrounding rock mass were analyzed on the basis of field geological survey and the preferred orientation of the main discontinuities were derived. Then the displaceable blocks distributing on the roof and sidewalls of main chamber were searched out taking the intersecting relationship of discontinuities into consideration. Then the failure mode and the coefficient of stability of the displaceable blocks were studied respectively. (2)The rock mass quality was assessed based on the data obtained from exploration adits with the methods of engineering geological classification for surrounding rock mass, BQ, RMR and Q-system successively. And then the correlations between the assessment results of different methods were discussed. (3)Based on the analyses results of simple inference method and seismic focal mechanism and on the statistic results of measured geostress data, the direction of principal stress was derived and based on the analyses results of macro geological estimate and on the statistic results of measured geostress data the magnitude of principal stress was derived too. The influence of rapidly down-cutting of Yellow River on geostress field of studied zone was discussed. Then the evolution of geostress field accompanying with the down cutting of Yellow River and was simulated with FEM and the spatial distribution features of geostress were discussed. (4)The influences of cavern shape, cavern scale and geostress on excavation effects for single cavern and the influences of distance between differentcaverns, rock mass quality and construction order etc on the excavation effects of caverns were studied. The features of multi-cavern effect of Laxiwa underground project were studied. (5) Selecting rock mass quality, excavation effect, multi-cavern effect and induced hazard effect as indexes, the stability classification scheme of rock mass surrounding large scale underground caverns was established. At last the stability of the surrounding rock mass of the main chamber of Laxiwa project was evaluated with this scheme.During the process of the fore mentioned analyses, some tentative works as follows were done.(1)On the basis of the fundamental of spatial analytic geometry, the basic method for displaceable block searching was put forward and the relevant program was written. With this program one can easily search out all the displaceable blocks and omitting of blocks, which is very common in searching blocks manually, can be avoided.(2)The coefficient of stability of blocks with failure mode II-2(that is, sliding on a single sliding surface, but confined by near intersecting line )was deduced.(3)The multi-cavern effect of Laxiwa underground caverns was studied on the assumption that all of the caverns were full face tunneled at the same time.(4)The stability classification scheme of rock mass surrounding large scale underground caverns was established. In addition to inherit the merits of the method of engineering geological更多还原