【摘要】：擬建牙根二級水電站位于四川省甘孜州雅江縣境內(nèi)的雅礱江干流上，是雅礱江中游規(guī)劃的第三個梯級電站，設計為混凝土重力壩，最大壩高153m，相應庫容2.54億m3，裝機容量990MW。壩基花崗巖體斷裂裂隙發(fā)育，在庫水頭的作用下可能出現(xiàn)因壩基滲流而導致水庫滲漏以及壩基巖體失穩(wěn)的問題。因此，研究壩基滲流問題具有重要的工程實用價值。 本文在分析壩址區(qū)結(jié)構(gòu)面發(fā)育規(guī)律的基礎(chǔ)上，詳細分析了壩基平硐和鉆孔結(jié)構(gòu)面資料，建立壩基滲流分析的地質(zhì)概化模型；根據(jù)鉆孔壓水試驗和裂隙統(tǒng)計資料綜合確定壩基巖體不同部位的滲透系數(shù)；利用Visual MODFLOW軟件分別對天然狀態(tài)和蓄水后壩基三維滲流場特征進行模擬；分析滲流對巖體力學性質(zhì)的影響，利用FLAC3D軟件模擬蓄水后滲流對壩基抗滑穩(wěn)定性的影響。 取得了如下主要成果： （1）總結(jié)分析了壩基巖體結(jié)構(gòu)面的發(fā)育規(guī)律，尤其對緩傾角結(jié)構(gòu)面的發(fā)育規(guī)律進行了重點研究，得出產(chǎn)狀為N40~50°W/NE∠20~25°的緩傾角結(jié)構(gòu)面發(fā)育具有絕對優(yōu)勢，其產(chǎn)狀穩(wěn)定、平直、延伸長大，，為構(gòu)造結(jié)構(gòu)面。根據(jù)平硐及鉆孔資料分析確定該組緩傾角斷裂在壩基巖體中共發(fā)育11條，其近似等間距發(fā)育，與陡傾角斷裂相互切割，構(gòu)成了壩基巖體滲流及抗滑穩(wěn)定的基本地質(zhì)模型。 （2）將壩基巖體的滲透結(jié)構(gòu)劃分為散體狀滲透結(jié)構(gòu)、帶狀滲透結(jié)構(gòu)及網(wǎng)絡狀滲透結(jié)構(gòu)三種，其中后兩種滲透結(jié)構(gòu)對壩基巖體滲流其主要控制性作用。帶狀滲透結(jié)構(gòu)主要由斷層及其影響帶組成，為壩基巖體滲流的主要通道；網(wǎng)絡狀滲透結(jié)構(gòu)主要由巖體內(nèi)的各種裂隙組成，為壩基巖體滲流的次級通道。 （3）通過鉆孔壓水試驗和滲透系數(shù)張量計算，得到壩基巖體的滲透性隨深度的增加而遞減，新鮮巖體內(nèi)斷層對巖體滲透性的增加作用不明顯，巖體滲透性主要隨卸荷分帶變化。將兩種方法進行相互結(jié)合，綜合選取壩基巖體的滲透系數(shù)。 （4）水庫蓄水后，兩岸山體內(nèi)地下水位線呈現(xiàn)先增高后逐漸降低的變化趨勢，蓄水五年后地下水位降低速度放緩，水位線趨于穩(wěn)定；重力壩的設置使兩岸山體出現(xiàn)了一定的繞壩滲流現(xiàn)象，右岸繞壩滲流現(xiàn)象明顯大于左岸；設置防滲帷幕后，滲流場向深部延伸，滲漏量降低；壩基巖體滲漏量較小，防滲帷幕能起到較好的防滲作用。 （5）壩基巖體發(fā)育不利于其抗滑穩(wěn)定的結(jié)構(gòu)面組合；地下水通過潛蝕結(jié)構(gòu)面性狀、劈裂結(jié)構(gòu)面寬度、降低巖體圍壓使巖體的力學性質(zhì)發(fā)生損傷；在不設抗剪齒槽的情況下，蓄水后重力壩會沿fh07和fh09發(fā)生2mm的錯動，剪應變貫通，穩(wěn)定性較差；設置抗剪齒槽后能有效控制fh07和fh09的錯動，使巖體的穩(wěn)定性增加。
[Abstract]:The proposed root-level hydropower station is located on the main stream of the Yamen River in Yajiang County, Ganzi Prefecture, Sichuan Province. It is the third step power station planned in the middle reaches of the Yamen River. It is designed as a concrete gravity dam. The maximum dam height is 153m, the corresponding storage capacity is 2.54 billion m3, and the installed capacity is 990MW. The fracture and fracture development of the granite body at the dam foundation may cause the seepage of the reservoir and the instability of the rock mass of the dam foundation due to the seepage of the dam foundation under the effect of the reservoir head. Therefore, it is of great practical value to study the seepage of dam foundation. Based on the analysis of the development of the structure surface of the dam site, this paper analyzes the data of the dam foundation and the surface of the drilling structure in detail, and establishes the geological model of the seepage analysis of the dam foundation. The penetration system of different parts of the dam foundation rock mass is determined according to the drilling water pressure test and the fracture statistics. The characteristics of the three-dimensional seepage field of the dam foundation after water storage are simulated by using Visual MODFLOW software, and the effect of the seepage on the mechanical properties of the rock mass is analyzed, and the anti-sliding stability of the dam foundation is simulated by using the FLAC3D software. In response. The following master has been obtained The results are as follows: (1) The development law of the structural surface of the rock mass of the dam foundation is analyzed and the development law of the surface of the gentle dip angle structure is studied, and the development of the slow-dip structure with the occurrence of N40-50 擄 W/ NE and 20-25 擄 has an absolute advantage. Its occurrence is stable, straight, extended, The structure surface is constructed. According to the analysis of the level and the drilling data, it is determined that the set of gentle dip faults have a total development of 11 in the dam foundation rock mass, the approximate equal-spacing development, and the steep dip angle fracture are mutually cut, so as to form the basis for seepage and anti-sliding stability of the rock mass of the dam foundation and (2) dividing the permeable structure of the dam foundation rock mass into three types of an aqueous dispersion-shaped permeable structure, a strip-shaped permeable structure and a network-shaped permeable structure, wherein the following two permeable structures are used for seepage of the rock mass of the dam foundation The main control effect is that the belt-like penetration structure is mainly composed of the fault and its influence belt, which is the main channel for seepage of the rock mass of the dam foundation; the network-like penetration structure is mainly composed of various fractures in the rock mass, which is the rock mass of the dam foundation (3) The permeability of the rock mass of the dam foundation is decreased with the increase of the depth, and the permeability of the rock mass is not obvious, the permeability of the rock mass is not obvious, and the permeability of the rock mass is not obvious. The two methods are combined with each other, and the comprehensive selection The permeability coefficient of the rock mass of the dam foundation. (4) After the reservoir is impounded, the water table line in the mountain body of both sides of the cross-strait is gradually reduced after the water storage is increased, and the water level decreases after the water storage for five years, and the water level line is stable; and the setting of the gravity dam is to make the mountain of both banks The seepage of the surrounding dam on the right bank is obviously larger than that of the left bank. After the anti-seepage curtain is set, the seepage field is extended to the deep part, and the leakage is reduced; and the leakage of the rock mass of the dam foundation is small, and the seepage resistance is low. (5) The development of the rock mass of the dam foundation is not conducive to the combination of the anti-slip and stable structure surfaces, and the mechanical properties of the rock mass can be damaged by the surface property of the submerged structure, the width of the splitting structure, and the confining pressure of the rock mass. In case of no anti-shear tooth slot, the gravity dam after water storage will be 2 mm in the fh07 and fh09, and the shear strain can pass through and the stability is poor; and the fh07 and fh09 can be effectively controlled after the shear tooth slot is set.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV223.4

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