外海沉管隧道回淤监测及防淤清淤技术

Technology of siltation monitoring, minimizing and dredging in immersed tunnel of open seas

港珠澳大桥沉管隧道在E15碎石垫层基床铺设后出现异常强回淤,为了摸清基槽的回淤强度及原因,开展一系列回淤监测研究,主要包括多波束扫测、回淤盒监测、含沙量监测等现场实测手段。为了减少回淤,开展覆盖防淤研究,并根据现场流场情况和基槽走向制定截淤坝、扰动等防淤措施。为了清除碎石基床的异常回淤,在整平船上增加清淤设备,并在E22进行清淤施工,效果满足设计要求。从后续管节施工情况看,该成套技术是可行的、有效的。

The Hongkong-Zhuhai-Macao Bridge immersed tunnel occurred abnormal siltation after laying the foundation of E15 gravel cushion. In order to find out the siltation intensity and reasons of foundation trench, we carried out a series of studies in siltation monitoring, including multi-beam bathymetry, monitoring of siltation box and sediment concentration. In order to reduce siltation, we carried out the research on coverage of silt prevention, and developed silt prevention measures of cut silt dam and disturbance according to the scene of the flow field and the direction of the base. In order to remove the abnormal siltation of the gravel bed, we increased the dredging equipment in the leveling ship, and carried out the dredging construction in E22, the effect meets to the design requirements. Based on construction of the subsequent pipe section, the siltation monitoring and minimizing method is feasible and effective.