摘要:
以贵阳市地铁2号线三桥站主体结构基坑抗浮为研究对象,根据长观孔3~5年地下水位与降雨量关系对地下水位动态变化进行分析,提出一种定量计算抗浮水位的取值方法:抗浮水位值包括三个部分,勘察期间场区地下水最高水位(H kmax)、可能的意外补给造成该层地下水位的上升值(ΔH 0)及该层地下水相对勘察时的最大变幅值(ΔH e);长观孔地下水位呈雨季升高、枯季下降的变化规律,最高水位出现在6、7月份;通过对4、5、6月份的降雨量与观测孔水位进行线性拟合,得到地下水位变化量与月降雨量变化量的线性变化关系;结合历史降雨量推测场区地下水位的最大升幅为2.26 m,进而计算场区的抗浮水位为1128.46 m.
Abstract:
This paper studies anti-floating groundwater level of main body structure foundation pit,with a case study of the metro line 2 at Sanqiao station,Guiyang.The relationship between long-term groundwater level monitoring data and rainfall data was analyzed.On this basis,a method for the calculation of anti-uplift water level values was put forward.Main result shows that,(1 )anti-uplift water value consists of three parts,i.e.the highest groundwater level during the site investigation,the groundwater level rise by unex-pected recharge and the maximum groundwater fluctuation rate compared to that of the site exploration peri-od;(2)The groundwater levels monitored fluctuate seasonally which commonly increase in rainy season and decline in dry season,with the highest water levels appear in June and July;(3)The linear relationship be-tween the change of the groundwater level and the change of monthly rainfall was obtained by the linear fit-ting of the rainfall in April,May and June;(4)Combined with the historical rainfall,the maximum increase of the groundwater level in the field area is 2.26 m,and the anti-floating water level in the field area is 1,128.46 m.
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