Research on key technology of large bagged sand construction in deep water of complex tidal sea area

In a land reclamation project, water depth variation and underwater topography inequality in the construction water region are large, making the ocean current direction and velocity significant difference. Restricted by these factors, the sand-laying by professional paving ship will be difficult. Through the field test, the opposite-pulled ship was used in large bagged sand construction, and satisfactory effect was obtained in the construction water region, widening the applicable range of the opposite-pulled technology. In the construction process, the professional laying ship was replaced by opposite-pulled ship, and the existing construction technology of the opposite-pulled ship was improved, that is, the floating pipe shunt and anchor drawing technology was adopted. Moreover the position was measured by the buoy at the four corners of the bag, and the bag lap was in stagger way. By this way, the construction efficiency and quality of large bag sand were greatly improved, and the filling time of a large bagged sand can be shortened by 25% with the filling bag body more and smooth. Also the positioning accuracy of bag sand is higher, which ensures the stability of interlayer anti-slip of filling embankment and also reduces the amount of riprap due to the offset of the laying position of the bag body. This technique solves the difficult problem of laying large bagged sand in deep water in complex tidal sea area. It is of low engineering cost, high overall strength of dike body and reliable structure. It is of great significance for the development of offshore deep water shoreline.