Xiaodae Tailings Dam Consolidation Settlement Experiment And Numerical Simulation

In this paper, Xiaodae tailings dam of Sichuan Lala copper mine is taken as example. First we take samples from the tailings dam, and then proceed laboratory tests, in order to get Physical and mechanical properties and consolidation characters, under the condition of different pressures. The experiments shall use oedometer and triaxial apparatus, meanwhile according to the "geotechnical test standard". Next step is the indoor dam stacking model test, and this simulation is for observing the dam, to see how the depth and variation of the structural composition and the saturation line change, when stacking till the designed value. In the end, use the common way of sedimentation coefficient of consolidation methods and numerical simulation(sigma/w software), to analysis the consolidation settlement characteristics and pore water pressure variation during the dam stacking. The main work and conclusions are as follows:(1) Introduced the concepts of category of tailing pond, structure grades and so on; made description of tailing pond current situation;(2)By laboratory geotechnical test, acquire functional relationship between permeability coefficient and void ratio. As the consolidation process, the permeability coefficient of tailings sharply reduced with the void ratio decrease. But when the void ratio decreases to a threshold, the permeability is coefficient.;(3) Introduction of one-dimensional consolidation theory; two methods to evaluate consolidation coefficient, which generally used on engineering computation; meanwhile, proceed consolidation tests on three different type of samples, under the condition of different pressures, eventually obtain curves and quantitative relationship between consolidation coefficient and pressure;(4) By indoor dam model tests, we simulate the process tailings pile dam, to obtain basic materials for the depth and variation of the structural composition and the saturation line, under the condition when stacking till the designed value;(5) Studied the regular pattern for consolidation settlement as the time change, with usage of relation between variable consolidation coefficient and stress. It found that when dam stacking is higher, the cumulative settlement would be proportional increase. Along the direction from the beach to dry sub-surface, the settlement gradually decreased. Using the SIGMA/W software, we simulated the change of consolidation settlement during 20 years period when tailing pond reached the designed value. The research achievement can be used on technical support for safety management of tailing pond.