Soil expansion stress test device capable of simulating immersion-air drying cyclic action

A soil expansion stress test device capable of simulating immersion-air drying cyclic action comprises a water box, a water storage box, an air-water exchanger and a waste water box, wherein the water storage box, the air-water exchanger and the waste water box are communicated with the water box. The water box comprises a porous collar arranged at the bottom of the water box, and a lower water-permeable stone in the porous collar. The lower water-permeable stone is provided with an annular knife. The middle part of the annular knife is provided with a soil sample. An upper water-permeable stone is arranged on the soil sample. A porous cover plate is arranged on the upper water-permeable stone. A pressure transmitting rod which extends out of the porous cover plate penetrates through a winged box cover which is connected with the water box. The top of the pressure transmitting rod which extends out of the porous cover plate is provided with an upper pressing board. A load sensor is fixed at top of the upper p