富水砂卵石地层地铁车站基坑降水优化研究

Optimization of Foundation Excavation Dewatering for Subway Station in Water Rich Sandy Cobble Stratum

为研究基坑含水层渗透系数对基坑降水的影响规律,依托洛阳轨道交通1号线青年宫站基坑降水工程,采用数值模拟分析方法,计算不同含水层渗透系数下基坑降水深度。针对基坑水位无法下降的问题,对基坑初始降水方案进行优化,并将基坑降水数值模拟计算结果与实测数据进行对比分析,验证方案优化效果。研究结果表明,降水初期,基坑水位下降速率较大,降水一段时间后,基坑水位下降速率逐渐减小,水位逐渐趋于稳定;随着含水层渗透系数的增大,含水层补水效率提高,当基坑降水井降水量一定时,降水井降水深度随着含水层渗透系数的增大而减小,结合施工现场实际降水情况确定本工程基坑含水层渗透系数为11.57~17.36cm/s;增加降水井数量可有效增大降水深度,减小降水速率。降水方案优化后,降水井降水深度数值模拟计算结果与实测结果差别较小,达到良好优化效果。

In order to study the influence law of the permeability coefficient of the aquifer on the foundation excavation dewatering,based on the foundation excavation dewatering project of Luoyang Subway Line 1 Youth Palace Station,the foundation excavation dewatering depth under different aquifer permeability coefficients is calculated by using the numerical simulation analysis method.Aiming at the problem that the water level of foundation excavation cannot drop,the initial dewatering scheme of foundation excavation is optimized,and the numerical simulation results of foundation excavation dewatering are compared with the measured data to verify the scheme optimization.The results show that at the initial stage of dewatering,the water level of foundation excavation decreases rapidly,and after a period of dewatering,the water level decreases gradually,and the water level tends to be stable.With the increase of the permeability coefficient of the aquifer,the water supplement efficiency of the aquifer is improved.When the dewatering of the dewatering well of the foundation excavation is certain,the dewatering depth of the dewatering well decreases with the increase of the permeability coefficient of the aquifer.Combined with the actual dewatering on the construction site,the permeability coefficient of the aquifer of the foundation excavation of the project is determined to be 11.57~17.36 cm/s.Increasing the number of dewatering wells can effectively increase the dewatering depth and reduce the dewatering rate.After the optimization of the dewatering scheme,the difference between the numerical simulation results and the measured results of the dewatering depth of the dewatering well is small,which achieves a good optimization effect.