The stepwise compression experiment of soil samples was carried out by WG single lever consolidation instrument (medium and low pressure) and NSIF geotechnical test control data acquisition and processing system, and the compression curve of the pore ratio and external load of the sample soil under the side limit condition and the change of soil stress measured at different depths of the soil were obtained: with the increase of external load, the pore ratio of soil gradually decreased, and the compressive modulus gradually increased. The larger the soil pore ratio, the smaller the allowable bearing capacity of the soil, and when the soil pore ratio is reduced to a certain extent, the stress strain change of the test soil tends to be stable.