Influence of Groundwater Seepage during Foundation Pit Dewatering on Soil’s Effective Stress

Abstract

Engineering dewatering not only makes soil release gravity water, increasing soil self-weight stress, but also lead to seepage occur along the two sides of waterproof curtain driven by water head difference inside and outside the pit, forming a hydrodynamic pressure, which are the main reasons causing ground settlement. In this paper, the equation of groundwater level drawdown funnel curve firstly is deduced, then we investigate the total effective stress increments of foundation pit soil with seepage works alone as well as both gravity drainage and seepage effect work together, and obtained the formulas for soil effective stress increment calculation. Studies show that the shape of soil settlement cross-section is closely related to the characters of water drawdown funnel curve.