北京城市副中心综合交通枢纽站止水帷幕深度影响分析

Analysis on the Depth Impact of the Suspended Impervious Curtain of Beijing City Sub-center Comprehensive Transportation Hub Station

以北京市城市副中心综合交通枢纽站深基坑为工程背景,基于Midas GTS NX有限元分析软件,研究悬挂式止水帷幕插入深度对渗流作用下深基坑渗流场及地表沉降的影响。研究表明:在水位降深相同的情况下,随着止水帷幕插入深度的增大,基坑周围的孔隙水压力减小,且分布逐渐趋于均匀,地下水位沿基坑侧壁的降幅逐渐减小;利用数值模拟得到的悬挂式止水帷幕基坑外地表沉降趋势与理论趋势相同,开挖完成后,地表沉降呈现“凹槽型沉降”的变形规律,随着止水帷幕深度的增加,基坑外地表最大沉降量减少了约29%,沉降影响区范围缩小了约21%,当帷幕超过最佳深度后地表沉降将趋于稳定。

Taking the deep foundation pit of Beijing City sub-center comprehensive transportation hub station as the engineering background,based on Midas GTS NX finite element analysis software,investigated the influence of the insertion depth of suspended impervious curtain on the seepage field and surface settlement of deep foundation pit.The results show that under the condition of the same water level drop depth,with the increase of the insertion depth of the suspended impervious curtain,the pore water pressure around the foundation pit decreased,and the distribution gradually becomes uniform;the decline of the groundwater level along the side wall of the foundation pit gradually decreased;the surface settlement outside the foundation pit of suspended impervious curtain obtained by numerical simulation is the same as the theoretical trend.After excavation,the surface settlement shows the deformation law of"fluted settlement".With the increase of suspended impervious curtain depth,the maximum surface settlement outside the foundation pit is reduced by about 29%,and the area affected by settlement is reduced by about 21%.When the curtain exceeds the optimum depth,the surface settlement tends to be stable.