OPTIMAL DESIGN OF WELL POINT SYSTEM FOR DEWATERING

Abstract

The most important input parameters for selecting and designing a dewatering system are the height of the ground water above the base of excavation and the permeability of the ground surrounding the excavation. Depending upon the capacity of the machine, the .manpower and time available the excavation work proceeds at certain rate. The design of dewatering system starts with estimation of the inflow quantities. In addition to knowing the permeability of the formation, the depth and plan dimension of the excavation must be known. Duration of dewatering as it relates to power consumption, operating and maintenance cost, installation cost, discharge facility usage cost are important for determining which is the most economical set up. Then selection of a system that will perform economically for the parameters and constraints set forth can be accomplished. Size and spacing of the wells or well points and pump sizes are key in design analysis. Continuous pumping and maintaining water table much below the trench bed means more consumption of energy. Also the water level can be maintained by operating less number of high capacity wells or large number of wells with low capacity. There are effective location of well which lead to more drawdown. All these aspects lead to the fact that there is a pumping schedule and arrangement of well locations that will lead to a minimum cost of pumping....