A COMPARISON BETWEEN NUMERICAL AND ANALYTICAL METHODS FOR PREDICTION OF TEMPORARY GROUNDWATER DRAWDOWN

Daniel Vélez¹; Celso Romanel¹

¹ Potifical Catholic University of Rio de Janeiro

doi:10.20906/CPS/CILAMCE2015-0877

Resumo

Abstract. When deep excavations reach the phreatic level in soil deposits, either for construction works or excavation stability, a temporary groundwater drawdown is generally required. For the initial design of the pumping system, the engineer frequently makes use of analytical formulation for confined or unconfined aquifers, developed on basis of a steady state flow of water through a homogeneous and isotropic layer of infinite lateral extension. The analytical method approximates the dewatering system as an equivalent circular well or trench of great length, and its distance to a recharge aquifer source or impermeable barrier is taken into account by means of the method of images. In this paper comparisons are made between analytical and numerical solutions obtained by the finite element method through 3D simulations of groundwater drawdown, considering several excavation geometries and recharge source distances.

Palavras-chave: Temporary groundwater drawdown; Finite element model; Analytical drawdown prediction.