复杂岩溶水库成库条件及岩溶渗漏分析

发布时间：2018-06-20 02:11

本文选题：岩溶水库 + 岩溶发育特征　；参考：《成都理工大学》2017年硕士论文

【摘要】：水利工程建设随着我国经济、技术的进步得到了快速的发展,促使了水利工程向越来越复杂的地质条件区域(如构造发育带、岩溶发育区)挺近。我国西部山区存在丰富的水资源,同时也是构造、岩溶发育的区域,在西部地区进行水利工程建设经常遇到岩溶发育问题,为了发展岩溶地区丰富的水利水电资源,首先要解决的是因为喀斯特的岩溶发育而带来的许多复杂工程与水文地质问题,如水库坝址、水库邻谷、水库库区的岩溶发育所带来的渗漏问题,由于不良地质现象如喀斯特岩溶现象的存在,对水利工程的建设期以及运营期都将产生重大的影响,也是整个项目成败的关键因素。因此,对建设区岩溶发育的调查研究及发育程度的判定在水利项目建设的可行性论证时期起着重要的作用。本文中拟建的长浪坝水库位于施甸县西部山区李为地河上游,属施甸河支流,坝址区右岸分布的主要地层为志留系中统的上仁和桥组(S2r)碳酸盐岩夹碎屑岩(砂泥岩、页岩)地层,发育有微小溶孔、溶槽、溶隙以及规模较小的溶洞;坝址区左岸分布的主要地层为石炭系上统卧牛寺组(C3w)火山岩地层,两个地层在河谷区以断层方式接触,断层走向与拟建的大坝接近垂直。水库建成开始蓄水后,岩溶发育区及断层破碎带等可能形成有利的水库渗漏通道,将会对工程的经济效益及利用率产生较大的影响,甚至还可能导致工程失败。在野外的现场地质调查及前期的勘探资料的基础上,从坝址区所处的地质环境条件入手,对李为地河长浪坝水库坝址区岩溶水文地质条件等进行了系统的分析;结合钻孔的压水试验,简单分析了研究区岩体的渗透特性并计算了岩体的透水率;然后对坝址区的渗漏条件、可能存在的渗漏通道以及渗漏方式进行了阐述,采用水文地质学解析解方法对可能存在的渗漏通道进行渗漏量估算,再利用visual modflow软件进行坝址区地下水渗流场的三维数值模拟分析,通过模拟得出可能渗漏部位渗漏量情况,并提出了防渗建议。主要结论如下:1)分析了坝址区的水文地质条件:坝址区的地下水类型分为潜水和承压水,研究区的承压水存在于右岸山脊的碳酸盐中,潜水在整个研究区均存在;坝址区地下水与岩石相互作用时间具有一定的差异性,碳酸盐岩中主要表现出方解石饱和指数小于零,地下水以溶蚀为主;火山岩中则表现为方解石饱和指数大于零,有发生沉淀的趋势。坝址区水化学简分析测试分析表明,坝址区水化学主要类型为HCO3-Ca型水。2)坝址区物探、钻孔资料及地表调查结果显示,坝址区内大部分碳酸盐岩表层被红粘土覆盖,仅于坝址区左岸山脊较集中出露,此处地表溶沟、溶隙、溶孔较为发育,且节理裂隙发育,形成强溶蚀带,成为了地下水的主要渗流通道。坝址区附近主要受顺河断层的影响,地层中裂隙及小规模断层较为发育,发育有溶孔、溶隙、小型溶洞及破碎溶蚀带,可溶岩结构面的切割组合易形成导水通道。3)通过钻孔压水实验数据分析,右岸岩体透水率值基本都小于3Lu,钻进中局部段地层出现承压性,表明岩体完整性相对较好,渗透性相对较弱,但透水性在垂向上分区不明显;坝基及左岸岩体灰岩的渗透性较好,透水率在4-5Lu;玄武岩体的透水率在2Lu左右。4)在岩溶发育分析的基础上,结合对坝址区的可能渗漏通道条件及蓄水后的水动力条件的分析,认为坝址区主要的渗漏模式为裂隙性渗漏,其中又以坝基渗漏和左岸库首单薄山脊渗漏为主;而坝址区右岸山脊存在分水岭,不存在向低邻谷发生渗漏。利用水文地质学理论计算公式初步计算各渗漏通道的渗漏量:库区蓄水位在1845m时坝基和左岸山脊的渗漏量总计1328.52m~3/d;库区蓄水位在1840m时坝基和左岸山脊的渗漏量总计1037.24m~3/d;库区蓄水位在1835m时坝基和左岸山脊的渗漏量总764.87m~3/d;库区蓄水位在1830m时坝基和左岸山脊的渗漏量总计549.23m~3/d。5)对地下水渗流场数值模拟分析,对天然蓄水条件及重点防渗部位的进行了最大危险蓄水位(1845m)的工况模拟后,水库的总渗漏量分别为1406.71m~3/d和260.45m~3/d,可以看出对水库采取必要的防渗措施是非常必要的,可以有效的减小渗漏量。在对水库进行全断面防渗的情况下,切断了库水的横向绕防渗帷幕的运移及减弱了在垂向上的渗透,将进一步减小渗漏量,分别对不同蓄水高程下进行了渗漏量模拟:蓄水高程1845m时渗漏量为138.29m~3/d;蓄水高程1840m时渗漏量为99.83m~3/d;蓄水高程1835m时渗漏量为36.04m~3/d;蓄水高程1830m时渗漏量为25.34m~3/d。6)通过文中的研究结果可以得出:坝址区的地下水水位较高,可溶岩的岩溶较为发育,渗透性在构造带附近较大,加上库区的汇水面积和来水量较小,认为长浪坝水库在天然条件下的成库条件较差,成库的可能性较小,在采取了工程防渗措施后,通过渗漏量的计算,认为蓄水水位为1835m时有较高成库条件和较好的经济效益。
[Abstract]:With the rapid development of the economic and technological progress of our country, the water conservancy project has made the water conservancy project close to more and more complex geological conditions (such as the tectonic zone and the Karst Development Zone). There are abundant water resources in the western mountainous areas of our country, at the same time, it is also a region of tectonic, karst development and water conservancy projects in the western region. The problem of karst development is often encountered. In order to develop the rich water and hydropower resources in karst areas, the first thing to solve is that many complicated engineering and hydrogeological problems caused by the development of karst in Karst, such as the dam site, the adjacent valley of the reservoir and the karst development of the reservoir area, are caused by the bad geological phenomena. For example, the existence of karst phenomenon in Karst will have great influence on the construction period and operation period of water conservancy projects, and it is also the key factor for the success or failure of the whole project. Therefore, the investigation and Research on the development of karst in the construction area and the determination of the development degree play an important role in the feasibility demonstration period of the construction of water conservancy projects. The Yangtze River is located in the upper reaches of the Li Di River in the western mountain area of Shidian county and is a tributary of the Shidian river. The main stratum in the right bank of the dam site is the upper carbonatite (S2r) carbonate clastic rock (sand shale, shale) strata in the middle of the Silurian system, which has small dissolved pores, slots, dissolving gaps and small karst caves; the main distribution of the left bank in the dam site is the main distribution. The strata are volcanic rocks of the upper Carboniferous series of lying niuusi formation (C3w). The two strata are exposed to the fault mode in the valley area. The strike of the fault is close to the proposed dam. After the reservoir is built, the karst development zone and the fault fracture zone may form a favorable reservoir leakage passage, which will produce the economic benefit and utilization rate of the project. On the basis of field geological survey and preliminary exploration data in the field, based on the geological environment conditions in the site of the dam site, the karst hydrogeological conditions of the dam site area of the Li Chang River Long Lang dam reservoir are systematically analyzed, and a simple analysis is made with the pressure water test of the borehole. The permeability of the rock mass in the study area is calculated and the permeability of the rock mass is calculated. Then the leakage condition, the possible leakage passage and the leakage mode are expounded. The seepage quantity of the possible leakage passage is estimated by the analytical solution of hydrogeology and the Visual MODFLOW software is used to carry out the groundwater in the dam site area. The seepage field of the seepage field is simulated and analyzed, and the seepage quantity of the possible leakage part is obtained, and the seepage prevention suggestion is put forward. The main conclusions are as follows: 1) the main conclusions are as follows: the hydrogeological conditions of the dam site area are analyzed: the groundwater type in the dam site is divided into dive and confined water, and the bearing water in the study area exists in the carbonate of the right bank ridge and dives in the whole area. The interaction time between the ground water and the rock in the dam site is different. In the carbonate rock, the calcite saturation index is less than zero and the groundwater is mainly dissolved. In the volcanic rock, the calcite saturation index is larger than zero, and the precipitation tendency is more than zero. The hydrochemical analysis and analysis of the dam site area It shows that the main type of Hydrochemistry in the dam site is HCO3-Ca type water.2) geophysical prospecting, borehole data and surface investigation results show that most carbonate rocks in the dam site are covered with red clay, but only in the left bank ridge of the dam site, where the surface of the surface is dissolved, dissolved and dissolved, and the joint fracture is developed and a strong dissolution zone is formed. It has become the main seepage channel of groundwater. The vicinity of the dam site is mainly affected by the Shun River fault, and the fracture and small scale faults in the stratum are more developed, and there are dissolving holes, dissolving gaps, small karst caves and broken dissolution zones, and the cutting combination of the karst structure surface is easy to form the water guide channel.3) and the right bank rock permeability is permeable through the drilling pressure water test data. The rate is basically less than 3Lu, and the strata in the middle section of the drilling are under pressure, indicating that the integrity of the rock mass is relatively good and the permeability is relatively weak, but the permeability is not obvious in the vertical zoning; the permeability of the limestone in the dam foundation and the left bank is better, the permeability is in the 4-5Lu, the permeability of the basalt rock is about 2Lu.4) on the basis of the analysis of the karst development. According to the analysis of the possible seepage channel conditions and the hydrodynamic conditions after the storage of the dam site, the main seepage mode of the dam site is fissure leakage, in which the seepage of the dam foundation and the leaking of the thin ridge of the left bank are the main seepage, and the ridge of the right Bank of the dam site has a watershed, and no seepage to the low adjacent valley is found. The theoretical calculation formula calculates the leakage of each seepage channel preliminarily: the leakage of the dam foundation and the left bank ridge is 1328.52m~3/d when the reservoir area is at 1845m; the leakage of the dam foundation and the left bank ridge is 1037.24m~3/d when the reservoir area is at 1840m; the leakage of the dam foundation and the left Bank ridge is always 764.87m~3/d; the reservoir area is stored in the reservoir area, and the reservoir area is stored in the reservoir area. When the water level is at 1830m, the leakage of the dam foundation and the left bank ridge is 549.23m~3/d.5). The numerical simulation analysis of the seepage field of the groundwater, the simulation of the maximum dangerous storage position (1845m) of the natural water storage conditions and the key impervious parts, the total leakage of the reservoir is 1406.71m~3/d and 260.45m~3/d respectively. It can be seen that the reservoir is necessary to be taken. The seepage prevention measures are very necessary and can effectively reduce the leakage. In the case of full section seepage prevention of the reservoir, the migration of the lateral seepage prevention curtain of the reservoir and the seepage in the vertical direction are cut off, and the leakage will be further reduced. The seepage quantity is simulated under different water storage elevation, when the water storage elevation is 1845m respectively. The leakage amount is 138.29m~3/d; the seepage amount is 99.83m~3/d when the water storage elevation is 1840m; the seepage amount is 36.04m~3/d when the water storage elevation 1835m is 36.04m~3/d; the leakage of the storage elevation 1830m is 25.34m~3/d.6). Through the research results in the paper, it can be concluded that the groundwater level of the dam site is high, and the karst of the karst is more developed, and the permeability is larger near the tectonic zone. In the upper reservoir area, the water catchment area and water amount are small. It is considered that the reservoir condition of the reservoir in the natural condition is poor and the possibility of the reservoir formation is small. After the seepage control measures are taken, the reservoir water level is 1835m and the reservoir condition and the better economic benefit are considered.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV697.32;P642.25

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