Correlation analysis of impact force of debris flow on bottom bed and flow characteristics based on solid-liquid two-phase experiment

ObjectiveWith the development of environmental seismology, ground motion signals have gradually become an effective means of debris flow monitoring and warning, which has the advantages of far distance, no contact and containing dynamic information. At present, many studies have been carried out on the relationship between ground motion signal generated by debris flow and the basal force, but the relationship between the basal force and the flow characteristics is not clear, which leads to the difficulties in the establishment of debris flow inversion model. Therefore, it is urgent to study the relationship between the basal force of debris flow and its flow characteristics from the perspective of the basal force of debris flow.MethodsFirstly, a small-scale flume model was designed based on dimensionless analysis and similarity theory. A sensor module was installed in the middle of the bottom of the flume 3 meters away from the gate of the material pool, including a unidirectional force sensor, a three-directional acceleration sensor and a pore water pressure sensor, which was used to collect the basal force, acceleration and pore water pressure. A high-speed camera is mounted on the side to record the simulated debris flow. Secondly, 16 groups of flume experiments with different flow characteristics were designed under the control of three influence factors. Sensors collected data, high-speed cameras recorded the flow process, and PIVlab was used to calculate the flow parameters (velocity and flow depth) of each group of experiments. Finally, the data is analyzed to study the relationship between the basal force of the solid-liquid relative bottom bed and its flow characteristics. Combined with the moving images recorded by the high-speed camera, the particle movement in the simulated debris flow with different flow characteristics is analyzed from the dynamic point of view, and the change law of the basal force is explained.