水库岩溶渗漏及防渗研究综述

岩溶地区水库渗漏是可溶岩地区兴建水利枢纽的主要工程地质问题之一,尤其是在可溶岩广布、岩溶发育强烈、地形复杂地区,岩溶渗漏成为了该类地区水利水电工程的一个普遍问题.库区的岩溶渗漏不仅影响建坝后的正常蓄水,还将危及坝体的安全与稳定.因此,有必要对库区渗漏,特别是岩溶地区的库区渗漏进行渗漏机理、渗漏特征、渗漏条件等进行详细分...     

复杂岩溶水系统势汇区建坝成库可行性研究

北盘江流域沿线山高谷深,岩溶水文地质条件复杂,局部区域水资源短缺,岩溶渗漏问题成为水利水电工程建设的瓶颈。文章综合地质调查测绘、钻探及物探、水文地质试验、岩溶水系统分析、地下水均衡分析等方法,论证了PCH水库不会发生邻谷渗漏及绕坝基深部的岩溶管道型渗漏,但发生溶隙型渗漏的可能性较大。采用有限元法模拟溶隙渗漏显示:随着T₁yn1-1灰岩溶蚀率的增大,坝基抗滑稳定系数稍有降低,潜在失稳模式为后缘剪断T₁yn1-2岩体,前缘沿T₁yn1-2层内岩屑夹泥型软弱结构面剪出;坝基渗漏量呈线性增加,T₁yn1-1灰岩溶隙密集带为坝基主要渗漏区。当溶隙密集带沿T₁yn1-1灰岩与T₁yn1-2泥灰岩接触带水平发育且集中分布时,坝基抗滑稳定系数将明显减小,坝基渗漏量将明显增大;当溶隙密集带垂直发育、分散发育或主要分布于坝后区域时,其对坝基抗滑稳定及坝基渗漏量影响微弱。岩溶水文地质分析及数值模拟均显示,复杂岩溶水系统势汇区下游区域多以溶隙渗漏为主,其工程影响有限,具备建坝成库条件。      

自强水库库区工程地质评价与坝线选址研究

自强水库位于陕南秦巴山地中低山地貌区,水库为镇巴县备用水源地及旅游观光风景区,属小(1型水库。通过对库坝区地质构造、地层岩性、岩溶发育等工程地质条件分析可知,对工程建设及坝线选址有影响的工程地质问题主要为库区内发育逆冲叠瓦小断裂以及岩溶发育可能导致水库渗漏等。库区内无大型活动性断裂构造,构造较为稳定,且库区蓄水范围小,蓄水量不大,不易诱发地震。而拟选坝址位于自强河段,沟谷对称顺直,综合水库坝址区地形地貌、工程地质等条件进行坝线比选,推荐下游坝线为较为理想的坝线位置,可满足工程建设要求。     

工程水文地质学及其在水电工程中的应用概述

工程水文地质问题产生于人类工程活动与地质环境中岩土体和地下水之间的相互制约和相互作用过程中,由于问题本身的复杂性,目前对这类问题的研究尚处于相对分散的单一研究状态,缺乏系统的从地质机制分析到地质模型抽象,进而由模拟再现到发展趋势预测以及治理措施论证的全过程研究。本文在系统分析、总结水电工程中水 -岩和水 -工程建筑的作用类型及特征基础上,认为可能出现的工程水文地质问题主要是;水库诱发地震、岩溶渗漏、库岸及高边坡的稳定、坝基、坝肩抗滑稳定、枢纽区深层承压水问题等。     

Study on engineering-hydrogeological problems of hydroelectric project

Engineering-hydrogeological problems arise from the interaction between engineering activities and geological environment, in which rock-soil mass and groundwater are especially important constituents. However, up-to-date research on them is relatively dispersive and simple due to their complexity and lack of comprehensive and systematic study methods. Starting from geological analysis of mechanism to geological model based on geological regularities, the paper predicts the tendency of geological evolvement and puts forward proper measures to solve problems. In this paper, elevated water-sensitive structure in rock-soil mass, which mainly causes engineering hydrogeological problems, and problems in hydropower is discussed based on unique construction in Chinese Western hydropower projects. Engineering hydrogeological problems are reservoir induced earthquakes leakage from reservoir bottom in karst, stability of high slope at reservoir banks, sliding of dam foundation and dam abutment, and confined water at key positions which are introduced and determined by using water-sensitive factors (or structure) according to special hydrogeological conditions.     

贵州平寨水库左岸底层灌浆廊道大型充填溶洞及其形成机制

平寨水库坝址区以碳酸盐岩为主,岩溶较发育,水库左岸底层灌浆廊道大型充填溶洞,是水库地下工程施工开挖中揭露的规模最大、对水库渗漏影响最大、设计及施工处理难度最大的溶洞。本文以工程前期地质勘察工作为基础,在区域地貌、地质构造格局、地层岩性、地表及地下水系发育特征研究的基础上,结合工程防渗施工揭露的岩溶水文地质现象、洞穴充填物研究等,从可溶性岩层、地下水来源及运移途径、暗河冲刷与洞顶坍塌作用4个方面,对溶洞发育形成机制进行了研究。分析认为,鸡场背斜北西翼纵向张裂隙和横张裂隙及层间滑脱、断裂破碎带,为五里大洞鸡场洼地上坝洼地地下水向三岔河的径流提供了运移的原始空间与通道,形成溶洞的地下水为五里大洞鸡场洼地上坝洼地地下暗河,长期溶蚀作用使裂隙通道变为溶蚀宽缝并最终转化为岩溶管道,岩溶水沿此通道在左岸底层灌浆廊道桩号0+238～0+296m附近下中部岩体呈虹吸状循环,地下水的强烈冲刷与洞顶坍塌在溶洞形成过程中的作用巨大,后因深部径流条件改变,岩溶管道被逐渐堵塞,形成如今的大型充填溶洞。     

应用泉水均衡法分析四川省兴文县新坝水库岩溶渗漏问题

岩溶地区水库渗漏是碳酸盐岩地区兴建水利枢纽的主要工程地质问题之一,尤其是在可溶岩广布、岩溶发育强烈、地形复杂地区。拟建兴文县新坝水库地处岩溶地区,存在岩溶渗漏的可能性。通过对该水库库区地质概况、岩溶水系统进行分析研究,论证了水库潜在的三条岩溶渗漏途径均不会发生渗漏;并利用库区降雨量与泉流量进行水均衡计算,计算结果进一步论证了该水库不存在岩溶渗漏问题。     

CT-between electromagnetic detection revealed reservoir dam foundation karst morphological characteristics

The Dalongtan Reservoir Project is located in Jingxi County of Guangxi Autonomous Region; of which the masonry dam, is 249 meters long; it was completed and impounded in 1963. The dam foundation occurred a large number of water leakage; a number of vortex of leakage appeared; water flows under the dam into lower reaches. When emptying the reservoir, it is found that some karst collapses in the reservoir bottom. The past used conventional methods can only understand a single exploration drilling vertical direction of the geological conditions, not conducive to identify foundation for the development of horizontal and cave with broken spatial distribution. CT-between electromagnetic detection with drilling technology integration, it can make up for this deficiency. CT-between electromagnetic detection Dalongtan Reservoir dam foundation in the exploration of karst results show that this approach is feasible and effective.     

贵州冗赖水库岩溶成库条件分析

冗赖水库位于珠江流域的北盘江与南盘江两大水系之间的高原岩溶台地,左右岸外侧均存在低邻槽谷,坝址下游存在底部发育落水洞的大型岩溶海子,水库成库难度大,当地人饮水问题突出。通过岩溶水文地质调查、钻探、物探、连通试验等手段,从地形条件、地层岩性、地质构造、水文地质条件、岩溶发育特征等方面,对冗赖水库成库条件进行了分析论证。认为水库库盆底部依托隔水性岩体,不存在库水渗漏问题,但水库两岸受分水岭地下水位低、断层破碎带及岩溶发育等影响,存在库水渗漏问题,同时库首两岸可能存在顺平缓岩层面、溶蚀裂隙等产生渗漏问题。因此建议采用垂直防渗方式,防渗标准（透水率）小于3 Lu或防渗帷幕下限接稳定地下水位以下10 m,遇到溶洞等地质缺陷时应查明其分布特征,并根据实际情况降低防渗底线。      

文山小河尾水库岩溶渗漏水文地质条件与管道位置识别

小河尾水库是云南省文山州重要的集中式饮用水水源地,承担着22万人饮水供应任务,长年受到渗漏病害问题困扰。文章在水文地质调查基础上,提出小河尾水库岩溶渗漏水文地质条件的新认识:泥盆系坡折落组硅质岩和榴江组硅质岩构成南北两侧隔水边界,中间厚约40米的分水岭组灰岩构成渗漏条带,一NE-SW向压扭性逆断层F₁构成西侧隔水边界,库水主要向东北侧渗漏。采用大功率充电法和音频大地电磁法2种物探方法探测岩溶渗漏管道位置和深度,并实施钻孔验证,综合分析水文地质调查、物探和钻探成果,认为在分水岭组灰岩与上部榴江组硅质岩、下部坡折落组硅质岩岩性接触带附近分别存在强岩溶渗漏带,并分析2处强岩溶渗漏带分布特征、规模和充填性质,为小河尾水库渗漏治理提供依据,为以后岩溶地区类似水库渗漏病害问题调查治理提供借鉴。      

Gypsum-karst problems in constructing dams in the USA

Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30–60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US $12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming.     

Interconnection of karst systems and flow piracy through karst collapse in layered carbonate rocks

A new mode of interconnecting karst systems separated by impermeable bed due to karst collapse was discovered in the study of dam site in Guizhou, South China. Karst flow may be diverted from conduits in one layer to another, thus forming a connected karst system. Comprehensive methodology and techniques used in the investigation included surface geological surveys, geophysical investigations, special drilling, and tracer tests. In the stage of preliminary study, the karst conduits were considered to be developed separately along individual karstified layers. However, further investigation shows that karst collapse may be associated with conduit and cavern development, damaging the impermeable bed and its watertight function. Accordingly, a new pattern of karst conduit system was reestablished. The results obtained enable the dam designer to plan a reliable alternative for seepage protection.     

清华洞暗河堵洞成库与防渗技术

为解决富宁县城供水及其附近乡村农业灌溉问题,对清华洞暗河进行堵洞成库。水库设计总库容9934万m3,堵洞体高87.5m,最大蓄水深约116m。地质调查发现,库盆及四周均分布有较完整的相对隔水层、隔水层,山体雄厚,泉点出露均高于水库设计蓄水高程,但是,枢纽区地质构造较为复杂,岩溶发育,暗河进口左岸有溶洞和断层溶塌体分布,引起绕坝渗漏的可能性很大。根据枢纽区工程地质条件,选择附近有D3g隔水层分布并能避开溶洞影响,同时距暗河进口较近而利于施工的0+085坝址段对清华洞暗河进行封堵,并采用上下两层悬挂式半封闭帷幕灌浆对溶塌体和其他岩溶裂隙通道进行防渗处理。经多年实践表明,本防渗技术可行,坝址、防渗帷幕灌浆线路以及灌浆设计合理,水库造价低,有效地解决了县城供水和下游2.26万亩农田及21.5万亩热区作物灌溉问题。      

孔间电磁波CT探测揭示水库坝基岩溶形态特征——以广西靖西大龙潭水库帷幕灌浆为例

广西靖西大龙潭水库枢纽,为浆砌石重力坝,坝轴线长249 工程于1963年竣工蓄水,同年坝基大量漏水,库内出现多处漏水漩涡,水从坝下穿流而过在下游涌出,当水库泄空后,发现库内有岩溶塌陷(落水洞)多处.以往采用常规的勘探方法仅能了解单个钻孔竖直方向的地质情况,不利于查清坝基横向连续发育的破碎带和溶洞空间分布.孔间电磁波CT探测技术与钻探相结合,正好可以弥补这方面的不足.孔间电磁波CT探测在大龙潭水库坝基的岩溶探测结果说明,这种方法可行有效,溶洞和破碎带探测结果还经过灌浆钻孔的验证.     

Palaeo-karst collapse pillars in northern China and their damage to the geological environments

According to statistics, there are a total of 39 sites of palaeo-karst collapse pillars in Northern China, as well as 3,650 palaeo-karst collapse pillars. Through an overall survey and analysis of the distribution regularities and formation mechanisms of palaeo-karst collapse pillars in the northern coal mine regions, this paper found that the rock formation structures, geological structures, karst characters, underground hydrodynamic conditions of karst and neotectonic movement conditions are basic geological bases for the formation of karst collapse pillars and rule the distribution of them. Karst collapse pillars apparently have three south–north regularities in terms of distribution, and they have resulted in severe damages to geological resources and environment in their distribution areas: mine water inrush causing and coal resources damage and influencing the impounding of reservoirs as well as the stability of dam sites. Based on the basic geological features of palaeo-karst collapse pillars in northern China, this paper also introduces the new methods of integrated prospecting of successive approximation to determine hydraulic conductivity of palaeo-karst collapse pillars.     

仙岭水库土坝渗流稳定分析及除险加固措施

根据湖南省仙岭水库的地质勘探资料,利用有限元进行计算分析,弄清了大坝的渗流情况,分析了大坝存在的渗漏和渗透变形问题,并提出了除险加固的措施,经过计算分析说明：所提出的措施是合理可靠的,所得出的结论可为同类土坝的安全鉴定、加固以及今后土坝设计、施工和管理提供借鉴。     

滇东高原罗平湾子水库岩溶渗漏机理及库外补漏设想

在总结和分析前人研究成果的基础上,结合云南省罗平湾子水库地层岩性、地质构造、水文地质工程地质条件、岩溶发育特征、水库汇流条件、多次补漏未遂等因素,对影响水库渗漏的主要因素进行分解,结果表明:岩溶强发育带地层中溶蚀孔、洞发育,土工膜铺盖封闭库底,蓄水后便在土工膜之下、地下水位之上的岩溶空隙中形成真空,在库水位频繁、大幅度波动条件下易发生真空吸蚀作用,充填物部分被淘空;库底以上的蓄水压力与库底以下的真空产生的负压叠加后形成附加应力,当附加应力大于孔洞之上岩土体的抗剪强度,或大于孔、洞充填物与洞壁之间的粘结强度时发生冲切破坏,这是导致水库多次补漏未遂,且同一渗漏片区重复发生岩溶塌陷、出现落水洞的主要原因。在库区内补漏具有很大的局限性,而在库区外适当部位设置防渗帷幕,不仅可根治渗漏,还可明显抬高地下水位,改善蓄水条件,扩大原设计库容数倍。      

Karst Hyporheic Zone及其研究进展

Karst Hyporheic Zone(笔者将之译为“岩溶交互带”)是近三年来新出现的一个岩溶术语,我国尚未开展“岩溶交互带”的研究工作,它主要是指岩溶地下水与周边岩溶基质(含沉积物、基岩)水之间物质能量活跃交替的地带。本文从“岩溶交互带”的概念来源、含义、最新的研究进展和监测技术发展等方面进行了总结,并就现存的问题和未来研究提出了看法。      

Optimization design and assessment of the effect of seepage control at reservoir sites under karst conditions: a case study in Anhui Province,China

Seepage analysis and assessment of the effect of seepage control at reservoir sites are essential parts of dam design and operations, and of considerable significance for the safe and economic design of the masses and hydraulic structures associated with reservoir sites. In this study, a systematic process is provided for the optimal design and assessment of seepage control of reservoir dams under karst development conditions. A reservoir dam planned for construction in the middle-upper reaches of the Huayang River in China is selected as a case example for illustration. A three-dimensional equivalent continuum seepage finite-element numerical model is applied to investigate the effectiveness of the proposed and optimized seepage-control schemes, and it is calibrated by an inversion analysis of the initial seepage field based on the flexible tolerance method and field penetration test data. By analyzing the sensitivity of seepage discharge to the length and depth of the grouting curtain, a safe and economic seepage-control optimization scheme is suggested. Additionally, the sensitivity of seepage discharge to the hydraulic conductivity of the limestone layer is analyzed, and the results show that the hydraulic conductivity of the limestone layer has a significant impact on the seepage discharge of the reservoir site. The methodology and results derived from this study can provide technical support and reference for the optimal design and assessment of seepage control for reservoir dam engineering under karst conditions.

     

岩溶关键带水文地球化学研究进展

岩溶关键带处于岩石、水、土壤、大气、生物五圈交汇地带。正确认识岩溶关键带的结构、特点及其水文地球化学过程是当前地球关键带与岩溶水科学研究的重点问题。本文基于对国内外相关研究成果的归纳整理,剖析了岩溶关键带水文地球化学内涵、岩溶关键带水动力垂向分带、岩溶关键带框架下的水文地球化学过程与机制, 探寻变化环境下岩溶关键带水文地球化学过程演变的规律与驱动机制。指出了当前研究中存在的薄弱环节:目前工作仅停留在传统岩溶地下水科学工作范畴,未从岩溶关键带框架体系的角度考虑植物冠层至岩溶含水层之间水文地球化学过程及其耦合关系,未考虑新污染物持续输入、地球大数据科学工程深入实施、全球碳排放路径逐渐改变等时代因素对岩溶水文地球化学研究的潜在影响。进一步的研究可以从以下方面开展:基于岩溶关键带框架体系的新污染物水文地球化学研究,基于大数据框架体系的岩溶水文地球化学研究,“双碳战略”下的岩溶水文地球化学研究,岩溶关键带水文地球化学驱动的物质转化与能量迁移过程及其耦合以及高分辨率监测、评估与模拟手段的综合应用。