高层建筑物地下室底板下的浅埋暗挖隧道内桩基托换技术应用

为实现深圳地铁1号和3号线老街站平行换乘,需在9层的永新商业城建筑物地下室下的软弱地基土层中扩建1个2层框架结构站台。首先自地下室底板下暗挖1条隧道揭示永新商业城5根桩基,并在隧道内采用连续梁形式对5根桩基（单桩最大重6 500 kN）同时实施主动托换。通过采用非线性数值分析软件ABAQUS对桩基主动托换各工况进行仿真模拟计算分析,在工程施工中通过量测数据的反分析精心指导施工,通过精细化施工组织保证了以连续梁形式同时主动托换多根桩同步顶升,最终确保了在该恶劣条件下桩基主动托换过程中上部建筑物沉降值控制在＋1～-1 mm。

Application of Pile Foundation Underpinning in Tunnel Mining under Shallow Cover below Basement Floor of High Building

A frame-structured platform tunnel with 2 floors needs to be excavated in soft soil strata below the basement floor of a high building,in order to achieve parallel transfer between Line 1 and Line 3 at Laojie Station of Shenzhen Metro.The 5 pile foundations of the building are revealed by means of mining a tunnel below the basement floor and are underpinned with 6 500 kN force by means of continuous beam structures.The underpinning conditions are analyzed by means of ABAQUS software.The measured data are analyzed so as to guide the construction.In the end,the settlement of the buildings is controlled within the range from ＋1 mm to-1 mm.