悬挂式止水帷幕圆形基坑承压含水层地下水非稳定流计算

针对悬挂式止水帷幕基坑中复杂的地下水流动，建立了考虑止水帷幕的圆形基坑承压含水层地下水非稳定流动计算模型。通过对地下水流动计算模型的Laplace变换和有限Fourier余弦变换，推导了Laplace空间的水头降深解，采用Stehfest数值逆变换提出了悬挂式止水帷幕圆形基坑承压含水层地下水非稳定流水头降深半解析解。在验证计算方法正确性和数值逆变换计算准确性的基础上，利用工程实例验证了计算方法的工程适用性。分析了悬挂式止水帷幕插入深度对圆形基坑地下水流动的影响规律，阐明了止水帷幕对基坑内外地下水控制的积极作用，为合理开展悬挂式止水帷幕圆形基坑承压含水层的减压降水设计提供了计算方法。

Calculation of non-steady groundwater flow in confined aquifer of a circular excavation pit with suspended waterproof curtain

The mechanism of groundwater flow in the excavation pit with suspended waterproof curtain is very complex. To explore the flow characteristics of groundwater caused by the implementation of the waterproof curtain and pumping well, a novel model is established based on the non-steady groundwater flow in a confined aquifer below a circular foundation pit. By applying Laplace and finite Fourier cosine transforms to the seepage model, the solution of water head drawdown in the Laplace domain is derived. Eventually, the time-domain non-steady groundwater flow drawdown in the confined aquifer subjected to excavation dewatering with suspended waterproof curtain is obtained using the Stehfest method. After the verification of the calculation method and the numerical inverse transformation, the calculation method is further verified in the application to a practical project. Parametric study is also carried out to assess how the flow characteristics of groundwater are influenced by the penetrating depth of the curtain. Results show that the implementation of the curtain has a positive effect on the groundwater control inside and outside the excavation pit. The proposed calculation method provides a new approach for the rational design of the decompression and dewatering of confined aquifer below the circular excavation pit with suspended waterproof curtain.