Valley Deformation and Slope Seismic Analysis near Tail Water Outlet of a Hydropower Station

Abstract

The safety and stability problems of high rock slope, such as weaken massif, fully developed geological conformations, widely unloaded or flabby rock layer, and squirming or sliding rock, are often encountered in engineering practice. So it is important to enforce the high slope rock deformation monitoring, and to process and analyze the measuring data timely. The high slope of the left-bank tailrace outlet of Wudongde hydropower station in Jinsha river is given as an example to analyze valley deformation, and to evaluate the seismic stability of high slope by utilizing rock deformation monitoring data. The field data of rock deformation of the left-bank tailrace outlet slope were collected by monitoring system, along with the field data of valley deformation. Based on monitoring data of the left-bank tailrace outlet slope deformation and valley width reduction of Wudongde hydropower station, the time and space deformation distribution regularity of rock mass were summarized. Analysis results and monitoring records reveal the general law of valley deformation, and demonstrate that excavating and other perturbations can quicken the creep deformation of rock mass, and the damage will not happen under action of earthquake.