Three-dimensional photoelasticity model test of inclined shaft on stress distribution in thick sand soil layer

Taking the main inclined shaft of a coal mine across thick sandy soil layer as the engineering case,estab- lished a physical model for the inclined shaft wall with the three-dimensional stress-freezing photoelastic method. A three-dimensional simulation for the stress of inclined shaft wall across thick sandy soil layer was made under the con- sideration of inclined roadway inclination. The whole-field maximum shear stress contour map was obtained from the stress-freezing photoelastic test and the changes of shaft wall stress in relation to shaft depth and circumferential angle were also analyzed. According to the results,the internal stress and its uneven distribution of the transverse section of shaft wall were much greater than that of the longitudinal section. The maximum shear stress centered on the inner ed- ges of shaft wall sides at a range of ±25°. The maximum shear stress on the top of inclined shaft wall was larger than the bottom. With the increase of shaft depth,the longitudinal stress showed a near-linear increase,but the rates of in- crease in relation to different circumferential angles differed greatly. Thus,the size and distribution of shaft wall inter- nal stress varied with different shaft depth.