Influence of the flooding speed of former lignite open pits on the stability of final slopes

University of Petrosani, Department of Environmental Engineering and Geology, University Street, no. 20, Petrosani, Romania

^* Corresponding author: faurfloring@yahoo.com

Abstract

Flooding the residual gaps of former lignite open pits is often applied worldwide, offering opportunities for the use of the lake and the reclaimed land, as well as many benefits, ranging from the restoration of ecosystems to the development of the local economy. The flooding process is conditioned by the available quantities of water from natural and/or artificial sources. Flooding can be done either by natural methods (underground water inflow plus intake of water from rainfall and superficial drainage), or by natural and artificial methods (water adductions from superficial collectors). Unlike artificial flooding, natural flooding has the advantage of reduced costs, but it is a long-lasting process. Depending on the flooding speed, as a result of rising water level and saturation of rocks from the final slopes, geotechnical phenomena such as landslides may occur. The paper aims at establishing the dependence between the rhythm of raising the water level in the lake and the geotechnical behavior of the rock in the internal dump. Depending on this, there is a need to accelerate the flooding process through adductions, as the hydrostatic pressure manifested on the final slopes determines the increase of their stability reserve.