Soil separation device for geological investigation

The invention relates to the technical field of geological exploration equipment, in particular to a geological exploration soil separation device which comprises a box body, a rotary separation part, a feeding mechanism and a driving part, the separation part comprises a rotating body coaxial with the box body, and the rotating body comprises an inner barrel, an outer barrel arranged outside the inner barrel in a sleeving mode and a spiral piece; the upper end of the outer cylinder is fixedly connected with the upper end of the inner cylinder in a sealed mode, the lower end of the outer cylinder is open, the lower end of the outer cylinder downwards extends out of the box body, the upper end of the inner cylinder upwards extends out of the outer cylinder, the upper end of the inner cylinder is rotationally connected with the cover body, and an annular screening cavity is formed between the outer cylinder and the inner cylinder. A plurality of first through holes are formed in the side wall of the outer barre