Abstract：
During shield construction of metro tunnels approaching the buildings, it is necessary to conduct grouting reinforcement for the soft and unconsolidated soil layers above the shield-driven tunnel to avoid damage of buildings caused by excessive uneven settlement, but it is difficult to implement for most of the traditional ground reinforcement techniques due to site coordination problem. The horizontal directional drilling and grouting (HDDG) technique was adopted to reinforce the water-rich sand stratum underlying the Xingzhongwei building group, taking the Dengcun-Jiangpu running tunnel project of Guangzhou metro line 14 as background. With combination of MWD (measurement while drilling) and HDD( horizontal directional drilling) techniques, horizontal grouting holes were drilled along the alignment of the shield tunnel, and repeated grouting at positioned points can be achieved by combining grouting valve tube and grouting packer. Practice proves that this new technology plays a significant role on controlling of uneven settlement of ground surface during shield tunnelling approaching buildings.
2019, Vol. 56 