Experimental infrared-radiometric investigations of stress variations on a borehole face in a model of the soil mass

A procedure for, and results of experimental investigations performed to substantiate the effectiveness of the method of infrared (IR) radiation in diagnosing changes in the stress state of soils over time are presented. The construction of a “large-scale” bench is described for the alternating loading of a relatively large (of the order of 0.35 m3) volume of soil. Variations in the stress state over time in the near-face zone of a “borehole,” which is arranged in a model of the soil mass, are recorded using synchronous recordings of signals from an IR radiometer and load-cell strain gages. The elastic nature of stress variations on the face of the borehole in an unsaturated sandy soil is revealed during alternating-sign stress variations “at infinity.” It is indicated that data derived from noncontact IR measurements will make it possible to record accurately moments of jumpwise stress variations in the soil “mass,” and evaluate their intensity.