Crouching Tiger Mountain Reservoir Dam Stability Seepage Monitoring And Data Analysis

Wohushan reservoir is the only one large-size reservoir in Jinan city. It takes primarily the tasks of flood control, water supply, springhead alimentation, and irrigation. The reservoir has been in operation for more than fifty years. After several times of rebuilding, strengthening and rehabilitation, it satisfies the national stipulated basic requirements for a safe reservoir. However, after several decades of operation of the artificial facilities for the observation of dam deformation and seepage, various degrees of distortions appear in observed data, especially for seepage observations where the standpipes was choking. To this end, rebuilding of a dam seepage observation system for the Wohushan reservoir was initiated by the Flood Control Office of Jinan City in September 2004.The items of the automatic seepage monitoring system include the monitoring of the phreatic lines in embankment and dam foundation, at the interface between the right-end of the dam and a mountain, and at the bypass of two opposite sluice piers of a spillway. According to the practical situation of the dam, seven cross-sections along the longitudinal axis of the dam was selected for the seepage monitoring. They are, from north to south of the dam, sections 0+020, 0+135, 0+415, 0+635, 0+835 and two sides of the spillway. In order to monitor the seepage loss of the dam foundation, additional standpipes were installed at the dam foundations of the sections 0+415 and 0+635. A total of 28 standpipes, each with a piezometer inside, were installed. Type 4500AL vibrating-wire piezometers made by Geokon and Type 2380 automatic data acquisition system made by Geomation of USA were used. The piezometers at the monitoring sections were connected by using purpose-made electric cables with the on-site automatic data acquisition systems, which were connected further by using optic cables with the personal computer in the central controlling room. With purpose-made software, the personal computer can make rounds of monitoring of the piezometers, store the data and transport them to the database established in a server in the central controlling room. In this way, the water head at each monitoring location can be recorded automatically. This system has been developed successfully and operated well since October 2005.This dissertation carries out the study of the applications of the above-mentioned project. The necessity, implementation method and construction workmanship of the automatic seepage monitoring were investigated in terms of the stability of the earth-fill dam of the Wohushan reservoir. The actually measured data and the theoretically derived data were analysed and compared for determining the practical operation situation of the reservoir. This provides some theoretical bases for guaranteeing the engineering safety and normal operation.