River flow bed hydraulic model

The invention relates to a river flow bed hydraulic model, and belongs to the field of water conservancy. The IPC of the hydraulic model is E02B1/02. High-pressure impact force of a high-pressure air bag driver is utilized for enabling a sampling probe to be instantly inserted into alluvial sediment, meanwhile, liquid nitrogen in a liquid nitrogen container rapidly enters the sampling probe, and the truth-preserving sampling process of bed sand is completed. A horizontal moving mechanical arm and a vertical moving mechanical arm are adopted to move along a horizontal guide rail and a vertical guide rail respectively, and the sampling position can be precisely controlled; due to the fact that the size of the high-pressure air bag driver is fixed, the falling distance of the sampling probe can be determined by the initial position of the vertical moving mechanical arm on the vertical guide rail. The real-time truth-preserving sampling of the bed sand section of the movable bed model is achieved, meanwhile the sampling efficiency is greatly improved, and the model has the great promotion role in precision and perfecting of test data.