Full-automatic pneumatic direct shear prepressing instrument

The utility model relates to a full-automatic pneumatic direct shear prepressing instrument. The full-automatic pneumatic direct shear prepressing instrument comprises an operation platform, as well as automatic pressurizing control devices, prepressing barrels, gas source solenoid valves, an air compressor and instrument base pressurizing devices, which are arranged on the operation platform. As the automatic pressure adjustment devices are arranged, the prepressing load can be refined according to property of a soil sample so as to achieve automatic graded loading; the pneumatic pressing manner is more stable than the old-fashioned manual weight-adding loading manner, and the soil sample is uniformly stressed; pressure relief can be also controlled respectively to realize unloading one by one; the full-automatic pneumatic direct shear prepressing instrument conforms to the test requirements, not only meets the demands on the prepressing reliability and precision of the soil sample, but also saves manpower and improves the working efficiency.