| Abstrakt: |
In the planning policy on modern energy system in China's "14th Five-Year Plan", it is proposed to accelerate the improvement of system for energy production, supply, storage and marketing, and to promote the large-scale and high-proportion development of renewable energy, so as to achieve the goal of "carbon peaking and carbon neutralization". Pumped storage is currently recognized as the most mature, reliable, clean and economical means of energy storage. However, the site selection is imminent in order to construct power stations for pumped storage. Taking Guizhou Province as an example, the current planning of site selection and the construction technology of power stations for pumped storage are seldom studied. Karst is distributed in more than 77% of Guizhou's land area, with the peak-cluster depression as the main geomorphological type. As a kind of natural negative terrain, the peak-cluster depression has hardly been excavated. But its excellent surrounding sealing, and wonderful geometric and engineering characteristics can save much investment in excavation support. Thus, the peak-cluster depression is an ideal place for building a reservoir. Taking the karst depression as a research object, this study focuses on the practical engineering problem of building a power station for pumped storage in the karst depression. The factors and their degrees affecting the suitability of reservoir construction in the depression are obviously different in different regions; therefore, some typical factors can only be selected as the evaluation indicators. These factors involve those having an important impact on the stability of the reservoir area, the leakage problem and the benefit of reservoir construction. In this study, samples of karst depressions were automatically extracted, and the attribute analysis and calculation were carried out based on DEM data and ArcGIS platform. According to the engineering practice, experts were organized to discuss and score so as to determine the influence factors of the evaluation model. Then the evaluation was conducted respectively in terms of terrain conditions, geological conditions, engineering conditions, environmental conditions, etc. The model of fuzzy comprehensive evaluation and the model of partial least square path have been constructed based on the seven key influencing factors of the decision-making of reservoir construction, including slope, reservoir capacity, petrofabric type, fault, hydrogeology, vertical distance between the upper and lower reservoirs and the ratio of distance to height. Taking the red line of ecological protection and the autothermal protection area as controlling variables, 488 candidate depressions in the study area were preliminarily screened and sorted in combination with the geological conditions of the supporting site. The results show that vertical distance, storage capacity and distance-height ratio play key roles in site selection. The application of GIS map overlay technology can eliminate the infeasible sites limited by environmental factors and the candidate depressions in the eco-environmental protection area. The geological conditions of the proposed lower reservoir and water conveyance power house were considered in the selection of the optimal candidate depressions, which effectively avoided the subjectivity and limitations of decision makers. A total of 6 of the top 10 selected depressions by the two models are consistent. Their good topographic conditions, suitable geological conditions, superior engineering conditions and good consistency indicate strong applicability and high reliability of the evaluation model. The two models are mutually matched. The depression selected is basically consistent with the quantitative standard of the index system, which has been well verified in engineering practice. No.1 depression of Baishui pond is the most suitable for the construction of power station for pumped storage. The research methods and results can further promote the resource utilization of karst depressions. [ABSTRACT FROM AUTHOR] |
