Three-dimensional net-type monitoring system and method for underwater landslide deformation

A three-dimensional (3D) net-type monitoring system for underwater landslide deformation, comprising a plurality of overwater monitoring stations and a plurality of multifunctional underwater 3D displacement meters;

• wherein the plurality of multifunctional underwater 3D displacement meters are arranged in a lattice, connected sequentially, and fixed to a surface of an overwater sliding mass and a surface of an underwater sliding mass, each of the overwater monitoring stations is fixedly connected to one multifunctional underwater 3D displacement meter on the surface of the overwater sliding mass, at least three multifunctional underwater 3D displacement meters are located on the surface of the overwater sliding mass and located on different straight lines, and a global positioning system (GPS) device is arranged on the overwater monitoring station and is used for acquiring spatial positions of the multifunctional underwater 3D displacement meters on the surface of the overwater sliding mass;
• the multifunctional underwater 3D displacement meter comprises a housing, four rotation shafts, four metallic lines, four displacement meters and a sensor assembly;
• the four rotation shafts are rotatably mounted in the housing and extend in a vertical direction, one end of the rotation shaft and the housing are connected to a compressible spring, four perforations penetrate the housing in a circumferential direction at intervals, the metallic lines correspond to the perforations in a one-to-one manner, one end of the metallic line is wound around the rotation shaft, and the other end thereof penetrates out of the perforation and is connected to the metallic line of the adjacent multifunctional underwater 3D displacement meter;
• and the displacement meters are fixed in the housing, and each displacement meter corresponds to the metallic line for measuring a take-up and pay-off length of the metallic line;
• and the sensor assembly comprises a three-axis acceleration sensor and a fluxgate, the three-axis acceleration sensor and the fluxgate being fixed in the housing and used for monitoring inclination angle change and azimuth angle change of the multifunctional underwater 3D displacement meter respectively.