普定水电站观测孔水文水化学特征及其潜在风险评估

在喀斯特地区建设和管理水电站难度较大,不但要考虑水库蓄水、岩溶的发育、以及大坝的安全稳定等因素,还需要考虑水文水化学对大坝和机组安全运行的影响。通过对贵州普定水电站大坝的坝底廊道和左右坝肩廊道水的监测和取样,对水温、水位、电导率、Ca2+、Mg2+和HCO-3进行了对比初步分析。得出以下认识:从水温和水位上看,其对大坝安全运行产生风险的可能性不大;根据对Ca2+、Mg2+和HCO-3的分析结果,发现三个廊道内水对大坝都具有不同程度的侵蚀作用,对帷幕灌浆的砼结构有不同程度的破坏,对冲沙闸附近的混凝土的侵蚀程度比其他位置要大;同时发现所有水的Ca2+浓度都较高,很可能对发动机安全运行造成影响,需要定期维护消除。

Hydrological and Hydrochemical Characteristics of the Observation Wells at Puding Hydropower Station and Their Potential Risk Assessment

In the karst areas, it is more difficult to construct and manage hydropower stations than in other areas. This is caused by not only considering the impoundment, karst development, security and stability of the dam as well as other factors, but also needing to consider the impact of hydrology and hydrochemistry on the safety of the dams and generator sets. Monitoring and sampling were performed at the corridor at the end of dam, corridors of right and left dam abutments, and reservoir at the Puding hydropower station of Guizhou Province, SW China, from 1994 to 1998, including water temperature, water level, electrical conductivity, Ca²⁺, Mg²⁺ and HCO₃^-. The following understandings are obtained:1) According to the temperature and water level data, the risk is lesser to dam safe operation; 2) based on the analysis results for Ca²⁺, Mg²⁺ and HCO₃^-, it is found that different degrees of water erosion to the dam occur in the three corridors, with varying-degree damage to curtain grouting concrete structures, and there is larger-extent erosion to concrete near the scouring sluice than in other locations; 3) the Ca²⁺ concentrations of all water are higher, it may be a hidden danger to safe operation of generator sets, therefore the regular maintenance is needed for eliminating this possibility.