【作者】 黄晨；

【导师】 吴德超；

【作者基本信息】 成都理工大学 ， 构造地质学， 2011， 硕士

【摘要】 雅鲁藏布江中游水力资源丰富,且位于西藏政治、经济和文化的中心地带,规划在西藏加查地区修建的加查水电站既满足了国家电力的需求,又促进西藏地区的经济发展和社会稳定。雅鲁藏布江及毗邻地区位处大陆最年轻的造山带——特提斯-喜马拉雅造山带,雅鲁藏布江大致沿雅鲁藏布江缝合带分布,干流大部分正处在或靠近雅鲁藏布江深大断裂带。因此,该区地质构造背景复杂,新构造运动强烈,近代地震活动频繁,地震烈度较高;河床覆盖较深,河谷两岸滑坡、崩塌堆积等物理地质现象发育,它们对该河段水资源开发及水电站建设产生了明显的影响。加查水电站具有优越的开发条件和前景,但加查水电站位处全球著名的纬向构造——特提斯造山系(带)东段,区域地质构造条件、地震地质背景和工程地质条件均较复杂。属一级构造的雅鲁藏布江断裂带从坝址下游3km附近斜穿雅鲁藏布江,总体沿雅鲁藏布江展布,走向近东西,陡倾南或北,略呈向南凸出的弧形,全长1000多公里。该断裂带是青藏高原南部一条规模巨大的大地构造边界,是印度板块向亚欧大陆几个阶段俯冲—碰撞的构造演化结果。沿断裂带发育白垩纪蛇绿岩套、混杂岩带和新生代基性、超基性侵入岩,并控制了北侧新生代初期中酸性、碱性侵入岩分布及熔岩喷发。雅鲁藏布江断裂控制了渐新世—中新世和上新世—更新世盆地,表现为南倾的多重逆冲,破碎带宽数百米至千米以上,动力变质作用十分显著,断层崖、断层三角面等地貌特征明显,显示出第四纪晚期有一定的活动性。区域上除规模巨大的近东西雅鲁藏布江断裂外,近南北向、北北东—北东向和北西向断裂也较复杂。除地质构造外,坝址区及加查地区地层、岩性也较复杂。加查地区位处喜马拉雅造山带核部,是新构造运动、地震、地热活动和新生代岩浆作用最强烈地区。青藏高原断块区新构造运动最直观的表现是强烈的垂向隆升和块体的水平滑动。其运动特征在时间上具有阶段性、继承性和新生性,空间上具有差异性等。主要表现为大面积整体、间歇性急剧抬升断裂;断块活动的继承性、新生性和差异性断裂等。本文在野外地质调查的基础上,通过遥感地质学、地球物理、地球化学、显微构造、年代学、地震地质、数据处理等方法、技术和手段,对雅鲁藏布江中游加查地区活动构造特征进行了深入研究,尤其是断裂构造的活动性方面,对工程的适应性做了客观的评价。通过调查发现雅鲁藏布江断裂的活动性具明显的分段性,总体而言,米林以东活动性较强,为全新世活动断裂;米林以西断裂活动性较弱,最新活动时代主要为中-晚更新世。加查水电站加查地区具晚更新世活动特征。在坝址区共发现11条断层。且主要为四级结构面,多为脆-韧性断层。这些断层具有方向一致、性质相同、规模较小、顺层或近于顺层特征。坝址区第四系发育,坝址座落在二级、三级阶地平台上。该区构造背景复杂,北距雅鲁藏布江区域性大断裂2-3km,加查坝址区第四系覆盖层之下是否存在规模较大的区域性隐伏断层,是该工程极为关注的问题。为了解决隐伏断层问题,本项目从以下方面着手:一是依据构造变形规律进行宏观判断;而是由远及近追踪调查,确定是否有较大规模断层延向坝址区;三是物化探手段予以确证。综合运用上述方法,认为坝址区覆盖层之下仅仅发育数条规模较小的断层,不存在较大的、具区域规模的断层。通过对雅鲁藏布江中游河段加查地区地质调查研究基础,根据地形地貌、地层、岩石、构造、物理地质作用、构造稳定性等因素的综合考虑,认为加查水电站开发条件较好。更多还原

【Abstract】 The hydraulic resources of the middle of Brahmaputra River are rich, and is located in Tibetan political, economic and cultural center of Jiacha area in Tibet, planning the Jiacha hydropower station built not only satisfy the demand of national power in Tibet, and promote economic development and social stability.Brahmaputra River and adjacent areas of the youngest situated continental orogenic belt– Tethys - the Himalayan orogenic belt, Brahmaputra River roughly along the Brahmaputra suture zone distribution, most are in or near the main Brahmaputra deep fault. Therefore, the geological tectonic background complex, new tectonic movement and intense, modern seismic activity is frequent, seismic intensity is higher; River valleys cover is deep, landslide, collapse accumulation cross-strait development, physi-geologic phenomena in this section are the water resources development and hydropower station have significant influence.Jiacha is the development of hydropower superior conditions and prospects, but the global famous hydropower anchordoguy Jiacha zonally tectonic - tethys eastern mountains (with) made, regional geological tectonic conditions, earthquake geological background and engineering geological conditions are more complicated. Brahmaputra tectonic fault of first-order 3km from downstream dam near inclined to wear the Brahmaputra, overall along Brahmaputra River exhibition cloth, to nearly things, steep sloping slightly north, south or the arc protruding southward, the span more than 1,000 km. The fault zone is a large scale of qinghai-tibet plateau, the southern border, the tectonic India’s several stages to Eurasia plate subduction of the collision of the tectonic evolution -- results. Along fault zones development cretaceous ophiolites sets, melanges belt and Cenozoic base sex, super base sex intrusive rocks, and control of the early Cenozoic north of acid, alkali intrusive rocks distribution and lava eruption. The Brahmaputra Faults control the Oligocene - Miocene and pliocene - pleistocene basin, performance for multiple thrust south poured hundreds of meters, broken bandwidth to km above, dynamic metamorphism, remarkable fault scarp, fault triangle surface features feature is apparent, shows a certain active late quaternary period. Area of immense size on the outside of nearly ns-trending the Brahmaputra fracture zone, nearly ns-trending, north east - north east north to and north west to fracture also relatively complicated. In addition to the geological structure in the dam site area and near-zone strata, lithology is more complex.Situated in the Jiacha area kernel part of the Himalayan orogenic belt, the new tectonic movement, earthquake, geothermal activity and Cenozoic magmatism most intense regions.The qinghai-tibet plateau new tectonic fault blocks the most intuitive performance is strong vertical uplift and block level sliding. Its movement characteristics in time in the new stage, the inheritance and has, on the space natural are different, etc. Main show is widespread overall, intermittent sharp elevating fault; Fault block of successive, new activities with difference fault and so on naturally.In this paper, on the basis of field geological survey by remote sensing geology, geophysics and geochemistry, microscopic structure, chronology, earthquake geology, data processing method and technique and tactics, and, for the Brahmaputra River middle plus check district activities tectonic characteristics were studied, especially the activity of the fracture structure of engineering adaptability made an objective evaluation.Through the survey found the Brahmaputra fracture with obvious subsection sexual activity, the general, who is stronger, the east activity for the holocene active faults; Who is weak, west fracture activity mainly for the latest activities in era of late Pleistocene.Jiacha hydropower station with near-zone late pleistocene activity characteristic.In the dam site area were found 11 of the faults. And mainly for quaternary structure surface, many for brittle-ductile faults. These faults are direction, same properties, smaller, bedding or nearly bedding features.In the dam site area quaternary system development, dam site is located in the secondary, tertiary terraces platform. The tectonic background complex, north from Brahmaputra River regional faults 2-3km, add check in the dam site area covering layers of quaternary system under the larger regional existence, is this project concealed fault the Paramount concern. In order to solve the problem, this project concealed fault from the following aspects: one is based on macro tectonic deformation law judge; But by far and near tracking survey, determine whether more large-scale faults in the dam site area; to delay Three is geophysical and geochemical prospecting method shall be confirmed. Comprehensive use of the above methods, covering layer in the dam site area under that only development several smaller fault, not there is greater, with regional scale fault.Through the middle reach of Brahmaputra River in the Jiacha area geology survey research foundation, according to the topography, formation, rock, structure, physical geology functions, structure stability factors considered, think of the Jiacha hydropower development conditions are good.更多还原