摘要
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T_(1)yn^(1-1)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T_(1)yn^(1-2)岩体,前缘沿T_(1)yn^(1-2)层内岩屑夹泥型软弱结构面剪出;坝基渗漏量呈线性增加,T_(1)yn^(1-1)灰岩溶隙密集带为坝基主要渗漏区。当溶隙密集带沿T_(1)yn^(1-1)灰岩与T_(1)yn^(1-2)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。
The topographic and geological conditions in the basin of Beipan River are complex with high mountains and deep valleys on both banks, strong karst development and deeply buried groundwater.Consequently, water resources are in great shortage in this area. The construction of water conservancy projects can effectively solve the problem of water shortage. However, karst leakage has become a difficult problem restricting the construction. By comprehensively using the methods of geological survey and mapping, drilling and geophysical exploration,hydrogeological test, karst water system analysis and groundwater balance analysis, this paper demonstrates that a leakage to the adjacent valley or along the karst pipeline deep under the dam foundation will not occur in the Pucha reservoir, but the possibility of solution crack leakage is great. The finite element method is used to simulate the solution crack leakage and analyze the engineering impact. Results show that with the increase of the dissolution rate of Tynlimestone, the anti-sliding stability coefficient of the dam foundation decreases slightly, and there is an inverse correlation between them. The regression equation is y=-0.081x +2.678. The potential instability mode of the dam foundation is that the Tynmarl rock mass is sheared at the upstream, and the bottom is sheared along the gently inclined upstream with weak structural plane of rock debris mixed with mud in Tynlayer. With the increase of dissolution rate of Tynlimestone, the leakage of dam foundation increases significantly, and there is a positive correlation between them. The regression equation is y=120.3x+224.8. The concentrated belt of solution crack is the main leakage area of dam foundation. When the concentrated belt develops horizontally and distributes intensively along the contact belt between Tynlimestone and Tynmarl, the anti-sliding stability coefficient of dam foundation will significantly reduce and the leakage of dam foundation will significantly increase.Therefore, the concentrated belt should be treated as a key area. When the concentrated belt is vertically developed, dispersed or mainly distributed in the area behind the dam, it has little impact on the anti-sliding stability and leakage of the dam foundation, and can be used as a secondary treatment area. Karst hydrogeological analysis and numerical simulation show that in complex karst areas, after groundwater is discharged from the surface in the potential catchment area, it mainly influxes in the form of runoff to the downstream river channel, and the vertical infiltration of water flow is relatively weak, so it is difficult to form karst pipelines bypassing the anti-seepage curtain and connecting the upstream and downstream in the deep part of the riverbed. The leakage form of dam foundation is mainly solution crack leakage,and its engineering impact is limited. Therefore, the catchment area of karst groundwater is suitable for dam and reservoir construction. In addition, according to the spatial distribution characteristics of the concentrated belt of solution crack, the targeted treatment of zoning grouting can improve the treatment efficiency and save investment.
作者
胡大儒
郑克勋
赵代尧
陈占恒
HU Daru;ZHENG Kexun;ZHAO Daiyao;CHEN Zhanheng(Power China GuiyangEngineering Corporation Limited,GuiyangfGuizhou 55008l,Ctoa)
出处
《中国岩溶》
CAS
CSCD
北大核心
2022年第5期736-745,共10页
Carsologica Sinica
关键词
水库渗漏
溶隙密集带
岩溶
数值模拟
北盘江
reservoir leakage
concentrated belt of solution crack
karst
numerical simulation
Beipan River
