Evaluation of optimized depth of waterproof curtain to mitigate negative impacts during dewatering

• Published in: Journal of hydrology (Amsterdam) Vol. 577; p. 123969
• Main Authors: Wang, Xu-Wei, Yang, Tian-Liang, Xu, Ye-Shuang, Shen, Shui-Long
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2019
• Subjects: confined aquifer; Depth of waterproof curtain; Dewatering; diaphragm; Environmental effect; equations; Filter length; mathematical models; wells; Filter length; Environmental effect; Dewatering; Depth of waterproof curtain
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2019.123969

•Evaluating environmental effects due to foundation pit dewatering by numerical simulation.•Impact on the environmental effects considering the interaction between the waterproof curtain and pumping wells.•Optimized depth of the waterproof curtain is evaluated, including the effective, suggested and control value.•Determining the optimized depth of the waterproof curtain according to the filter length of the pumping wells. Dewatering using a combination of waterproof curtain and pumping wells is commonly adopted to ensure the stability of foundation pits in multi-aquifer strata. However, dewatering is likely to result in environmental problems. This paper investigates the impact on surroundings owing to the interaction between the waterproof curtain and pumping wells by numerical simulation. The depth of the diaphragm wall penetrating the dewatering aquifer (D) and the filter length of pumping wells (L) are varied in the simulation. The relationship between approximate hydraulic gradient (Δi) or ground settlement outside the foundation pit (S) with curtain depth ratio RD (D over the thickness of the dewatering confined aquifer Ha) or filter length ratio RL (L/Ha) can be divided into three change parts, namely initial gradual, middle sharp and final gentle part. Three values of RD and RL, namely effective, suggested and control value, are proposed. RD and RL should vary between the effective and control value. The suggested value of RD and RL is recommended in actual engineering by comprehensive consideration. The effective, suggested and control value of RD can be calculated by a linear equation according to the value of RL.