CCS水电站引水发电系统洞群防排水关键技术

Study on the Key Technologies of Waterproof-Drainage of Diversion to Power Generation System Under the High Internal and External Water Condition for CCS Hydropower Station

厄瓜多尔CCS水电站引水发电系统轴线长达2800 m,内外水头均超过600 m、地下水补给量大、陡倾破碎带发育、洞室布置密集且纵横交错,致使施工突涌水问题突出、防排水设计重难点多。基于FLAC3D地下系统各工况渗流场分析进行内水外渗的敏感性分析,将3DEC大洞室节理裂隙水压力与地应力耦合进行楔形体多因素失稳分析,并结合基于高压压水试验的高压渗透特性分析,充水试验后特征时间点安全监测数据规律分析,进行防排水关键技术研究及控制措施认证。在上游高内水头引水系统采用透水衬砌,结合土工膜、固结灌浆、帷幕灌浆,以及下游发电系统采用基于排水洞的排水孔幕、系统排水孔等永临结合措施下,目前电站运行良好,各监测数据无异常且已经长期收敛,证明了高内外水头引水发电系统防排水设计的合理性。

The CCS Hydropower Station in Ecuador is characterized by the axis of the diversion to power generation system up to 2800 m long,the internal and external heads more than 600 m,the large groundwater recharge,the developed steeply dipping broken zone and the densely caves criss-crossly arranged,all of these result in gushing water problems during construction and many key and difficult points in waterproof-drainage design.According to the sensitivity analysis of internal water leakage based on seepage field’s analysis over various conditions by FLAC3 D,multi-factor instability analysis for wedges considering joints’and fractures’water pressure coupling of in-situ stress by 3DEC,combining with the high-pressure permeability characteristics analysis based on high water pressure tests results,features analysis of the safety monitoring data at the characteristic times after the water-filling test until recently,the research on key technologies for waterproofdrainage and also certification for control measures were finally put forward.Using water-permeable lining,combining with geomembrane,consolidation grouting,curtain grouting for the upstream high-head water diversion system,drainage hole curtain based on drainage gallery and system drainage holes for the downstream power generation system and so on,after all these permanent and temporary combination measures,the power station currently is running well,the safety monitoring data are not anomaly and have been converged for a long time,which certifies the rationality of the waterproof-drainage design for diversion to power generation system under the high internal and external water condition.