Study on Dynamic Crack Expansion and Size Effect of Back-Filling Concrete under Uniaxial Compression.

With the continuous expansion of the application range of gob-side entry retaining technology, the depth, height, and advancing speed of coal seams also increase, which brings great problems to the stability control of surrounding rock structures of gob-side entry retaining. As one of the main bearing structures of the surrounding rock, the stability of the roadway-side support body is a key factor for the success of gob-side entry retaining. In order to study the deformation characteristics and instability mechanism of roadway-side support body, based on the roadway-side support materials of gob-side entry retaining, the dynamic expansion test of back-filling concrete cracks under uniaxial compression was carried out.