Experimental and theoretical study on the surface subsidence by dewatering of foundation pit in phreatic aquifer
YANG Qingyuan1,2,ZHAO Boming1,2
(1. Key Laboratory of Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;2. School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)
Abstract:The ground surface subsidence outside the foundation pit caused by the incomplete well dewatering in the foundation pit under the condition that the aquifer inside and outside the foundation pit is not separated completely is studied in the foundation pit in Shenzhen Metro hub by means of the model tests and theoretical analysis. The effective depth due to incomplete well dewatering in the phreatic water stratum and the variation of the soil pore water pressure outside the foundation pit are revealed. The calculation formulas for the effective depth due to the incomplete well dewatering,the varying curve of water level outside the foundation pit and the percolation zone partition are put forward respectively. A simplified calculation method for the surface subsidence outside the foundation pit is proposed. The theoretically calculated trend of the surface subsidence curve is basically consistent with the measured results. However,the theoretical results tend to be conservative. Therefore,the simplified method is revised further by using the seepage principle of a by-pass seepage zone,which improves effectively the precision of theoretical calculation. Finally,the comparison between the in-situ monitoring data and theoretical calculated results shows that the proposed method is applicable in practical engineering.
杨清源1,2,赵伯明1,2. 潜水层基坑降水引起地表沉降试验与理论研究[J]. 岩石力学与工程学报, 2018, 37(6): 1506-1519.
YANG Qingyuan1,2,ZHAO Boming1,2. Experimental and theoretical study on the surface subsidence by dewatering of foundation pit in phreatic aquifer. , 2018, 37(6): 1506-1519.
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