Fig. 10 | Scientific Reports

Fig. 10

From: Theoretical and numerical investigations of the floor failure characteristics affected by coal mining near complex fault structures

Fig. 10

Stress distribution of floor under normal mining conditions. As the distance from the working face increases, tensile stress caused by the goaf load transitions into compressive stress because of the support pressure in the horizontal direction. The vertical stress in the coal seam near the floor on both sides is greater due to the support pressure, which diffuses outward and downward, forming a “pressure bulb” with a downward stress direction. Horizontal stress produces compressive stress near the floor on both sides and tensile stress near the goaf. Two shear stress bulbs of equal size and opposite directions form in the pressure zones on either side and spread outward. The force direction in the goaf is opposite to the pressure zones on both sides, creating two shear stress bulbs of equal size and opposite directions in the goaf area that spread inward under the combined effect of pressure from both sides and the goaf.

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