Uncertainty Analysis of Groundwater Heads around Underground LPGStorage Caverns by Using Stochastic Simulation Technique

Finite element methodology combined with stochastic simulation technique is developed toquantify the uncertainty of heads due to the spatial variability of hydraulic conductivity. MonteCarlo technique is applied to obtain an approximate solution to the two-dimensional steady flow ofa stochastically defined non-uniform medium. A nearest-neighbor stochastic process model is usedto generate a spatial correlation between hydraulic conductivity values in the block system.According to this study, the possible range of hydraulic gradient around cavern can be computedby using stochastic simulation rather than single value which is suggested by using deterministicmodeling. The term stochastic safety factor is suggested as an increment of head value at watercurtains, which should be added to make the all the hydraulic gradients surrounding the upperpart of the caverns larger than 1. By using this stochastic safety factor, the shortage of hydraulicgradient can be compensated and the risk of gas leakage due to heterogeneity of hydraulicconductivity can be overcome.

کلیدواژه ها:

Gas containment condition ، Stochastic safety factor ، Underground storage cavern ، Water curtains ، Stochastic simulation