# Analytical Solutions of Water Inflow for Foundation Pit in Confined Water Stratum
## 5 Conclusions  
This paper introduces a calculation model for water inflow in foundation pits with suspended waterproof curtains in confined water strata. Analytical solutions for water inflow in circular, strip, and rectangular foundation pits are derived. The calculation formula of the seepage path influence coefficient \(\alpha\) is derived by fitting with the numerical results. By comparing with a large number of numerical results of supplementary cases and site measured data, the correctness and universality of the analytical solutions in this paper are verified:  
(1) For the solutions of the water inflow in the foundation pit for the foundation pit with the suspended water-proof curtain in the confined water stratum, the seepage path influence coefficient \(\alpha\) has a great impact on the calculation results, and it should be determined by the scale of the foundation, the thickness of the aquifer, and the insertion ratio of the curtain;  
(2) The ratio of the foundation pit radius to the thickness of the aquifer (\(r_{0}/M\)) and the insertion ratio of the curtain (\(L/M\)) have a significant influence on the seepage path influence coefficient \(\alpha\), and the dividing points of their influence are \(r_{0}/M=3\) and \(L/M=0.7\), respectively;  
(3) For the water inflow calculation of the rectangular foundation pit, when the length-to-width ratio is greater than 1 and less than 2, the rectangular foundation pit is equivalent to a circular foundation pit according to the principle of equal areas, when the length-to-width ratio is greater than 5, the rectangular foundation pit is equivalent to a strip foundation pit according to the principle of equal areas, and interpolation should be adopted in other cases;  
(4) When the suspended water-proof curtain is selected as the measure to control the groundwater, the water control effect will decrease with the increase in \(r_{0}/M\). When the size of the foundation pit is large, the curtain should be inserted into the bottom of the aquifer to cut off the hydraulic connection between the inside and outside of the foundation pit.  
Conceptualization, [PERSON] and [PERSON]; methodology, [PERSON] and [PERSON]; software, [PERSON]; Writing--review & editing: [PERSON] and [PERSON]; Project administration: [PERSON] and [PERSON]; Supervision: P.L. All authors have read and agreed to the published version of the manuscript.  
The authors declare that this study received funding from Research Reserve Project of Beijing Infrastructure Investment Co., Ltd., grant number No. 2020-JT-28. The funder had the following involvement with the study: Conceptualization, [PERSON]; methodology, [PERSON]; Writing--review & editing: [PERSON] and [PERSON]; Project administration: [PERSON] and [PERSON].  
Data Availability Statement: Data will be made available on request.  
Figure 8: The variation in water blocking effect with \(r_{0}/M\).  
**Conflicts of Interest:** Authors [PERSON] and [PERSON] were employed by the company Beijing City Sub Central Station Integrated Hub Construction Management Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.