Dewatering Design And Optimization Of Construction Of The Beijing Subway Da Guan Ying Station

With the underground structures and high-rise buildings continue to adoptmore extensive, deep foundation applications, many based on depth below thegroundwater level, such a deep foundation construction process, oftenencountered in earthwork excavation underside in groundwater below. Necessaryto carry out the precipitation in order to ensure the smooth completion of civilconstruction, construction, the groundwater level is reduced to the necessarydepth to improve the operating conditions of the construction, to avoidlandslides and foundation bearing capacity decreased. Precipitation works moreand more the concern of the design and construction personnel.This article rely on the Beijing Subway Line7precipitation at Da guan yingstation project, with construction conditions in actual construction effectswell dewatering method, to provide reasonable parameters for the actual projectfor the purpose of checking by pumping test parameters to adjust the design ofprecipitation; optimization study of the construction process. Enhance thescientific nature of the program, improve the efficiency of construction.Details are as follows:Pumping test, the conditional venue construction period and cost controlreasons, it is impossible for each construction segment pumping test programoptimization by the use modflow groundwater flow simulation software, theestablishment of a groundwater flow model subroutine package of WEL simulatewell the simulation with IBD subroutine package Constant Head boundary weresimulated by a single well and group well pump volume (32m~3/h and50m~3/h)pumping1day,5days,10days,20days pumping contour map. According to thesimulation data on the number of wells and well structures, pumps specificationswere adjusted to achieve optimal pumping effect.In the actual construction process, Wu Kasi impact drilling into drillingtechnology is slow, the high cost is not suitable for road construction, sumup experience through on-site, combined with the water effects of the test wells, the eventual adoption of the hole drill wells process, while the well structurereinforced concrete pipe into the steel pipe and pvc pipe to ensure the watereffect at the same time improve the speed and cost savings.By subway precipitation on the surrounding environment. Principle andcalculation of land subsidence caused by the precipitation and the forecast forthe settlement. Comparisons of sand and gravel underlying the settlementcharacteristics of the actual settlement of the monitoring data and calculationof settlement monitoring data, and contingency plans for protection. Proposedto prevent land subsidence taken-groundwater recharge, recharge methods,recharge wells structure are discussed.