Characteristics and Connectivity Analysis of Hidden Karst in Jurong Pumped Storage Power Station Area, China

Abstract

Based on the hidden karst exposed in Jurong Pumped Storage Power Station, combined with the field exploration data, the temporal and spatial development characteristics of hidden karst in the power station area are analyzed using the methods of specific solubility and specific corrosion, water chemical composition analysis, borehole television imaging, tracer test, and water pressure test. The results show that the karst development in the study area can be divided into three periods: pre-Cretaceous, Pleistocene, and modern karst. Karst development is controlled by soluble rock, non-soluble rock, and their combination, and the development direction is basically consistent with the fault strike. Karst caves are mainly distributed below the elevation of 100 m, with different shapes and scales and randomness. Non-soluble rocks and impure carbonate rocks are widely distributed in the study area, and surface karst is not developed. The underground karst caves are filled with red clay, and the rate of groundwater circulation is slow. The existence of geological bodies such as rock veins causes the groundwater levels to have obvious double-layer characteristics, which results in weak connectivity between karst caves. Although the karst in the power station area has a certain hydraulic connection with the surface water outside the area, the hydraulic connection of karst in the power station area is generally weak. The research results provide a scientific basis for the anti-seepage measures of underground powerhouses.

Permeability Tests and Numerical Simulation of Argillaceous Dolomite in the Jurong Pumped-Storage Power Station, China

“…The normal storage level of the lower reservoir is 81 m with a total storage capacity of 20.35 million m 3 . The power station consists of the upper and lower reservoirs, dams, water conveyance systems, underground powerhouses, and permanent flood discharge structures (Figure 1) [26]. The upper reservoir is located on the southwest side of the main peak of Lunshan Mountain and is formed by excavating and filling the valleys of the main peak of Lunshan Mountain.…”

“…The strata in the power station area belong to the Ningzhen Formation, the Lower Yangtze Formation, and the Yangtze Formation Region. The lithology is mainly Sinian, Cambrian, and Permian strata (Figure 2) [26]. Sinian Dengying Group (Z 2 dn) mainly consists of fine crystal dolomite and internal clastic dolomite with a thickness of 150-227 m. The Cambrian Guanyintai Group (∈ 2-3 gn) is mainly composed of chert-bearing nodules or chert-banded dolomite mixed with argillaceous and calcareous dolomite with a thickness of 150-210 m. Baotaishan Group (∈ 1 p) mainly consists of a thin (less than 10 cm) to medium (10-50 cm) layer of argillaceous dolomite, siliceous dolomite, and cataclastic dolomite with an exposed thickness of 39-78 m. The argillaceous dolomite is thin, and the surface is strongly weathered.…”