雄安至北京大兴国际机场快线起步区地下段结构抗浮设防水位取值研究

抗浮设防水位直接影响到地下结构的安全与建设费用,在地下结构建设中至关重要,因此,科学合理地确定地下结构的抗浮设防水位具有巨大的社会意义和经济价值。本文以“雄安新区至北京大大兴国际机场快线地下工程段”为研究对象,系统分析了研究区水文地质条件以及地下水位年内年际动态变化规律,利用数值模拟法和类比预测法确定了地下结构抗浮设防水位标高建议值。结果表明,该场地区域浅层地下水水位埋深一般为5.0～20.0m,地下水水位标高一般为–10.0～1.0m。近五年场地浅层地下水水位标高一般为–5～–10 m,埋深一般为3.0～15.0 m,地下水位逐年升高,回升速率约1.0 m/a。地下结构抗浮设防水位标高取值建议取使用期抗浮设防水位采用数值模拟法预测结果。该成果服务了“雄安新区至北京大兴国际机场快线(R1线)”项目场地抗浮设计,为雄安新区重大工程建设项目的抗浮安全设计提供了示范。

Study on the Values of Anti-floating Fortification Water Level for the Underground Structure in the Starting Area of Xiongan–Beijing Daxing International Airport Express Line

The anti-floating water level directly affects the safety and construction cost of an underground structure. Therefore, it is of great social significance and economic value to determine the anti-floating water level of underground structures scientifically and reasonably. Taking the underground structure of the Express Railway Line from Xiongan New Area to Beijing Daxing International Airport as the research object, this study systematically analyzed the hydrogeological conditions and the interannual dynamic variation of the groundwater level in the study area and used the numerical simulation method and analog forecasting method to determine a recommended value of the anti-floating water level elevation of the underground structure. The results showed that the depth of shallow groundwater at this site is generally 5 to 20 m and that the elevation of the groundwater level is generally ?10 to 1 m. In the past five years, the elevation of the shallow groundwater level at the site has generally been ?5 to ?10 m, and the burial depth has generally been 3 to 15 m. The groundwater level has been increasing each year, and the recovery rate is approximately 1 m/a. The numerical simulation method was used to predict a recommended value of the anti-floating water level of the underground structure during its service life. The results serve the anti-floating design of the Express Line from Xiongan New Area to the Beijing Daxing International Airport (Line R1) project site and provide a demonstration of anti-floating safety design of major engineering construction projects in Xiongan New Area.