Current situation of gob-side entry retaining and suggestions for its improvement in China

Based on the article of “Status Quo and Suggestions for the Technology Development of Support along Gob-Side Entry Retaining in China” the work summarized the new technological development of gob-side entry retaining in China since the 21st century including the construction technology and method of gob-side fill. It develops from high-water and paste filling to soft mold walls and advanced pillar support. Support strength and isolated tightness have been greatly improved, with certain flexibility to adapt to roof settling. Basic support in the roadway along gob-side entry retaining has high preload, high strength, high stiffness, and large elongation after more than 20 years of development, which can control the large deformation of the surrounding rocks of the roadway and realize timely and active support. Single pillars are generally supplemented as reinforced support in the roadway to further maintain the stability and integrity of surrounding rocks. Statistical analysis shows that the key to the success of gob-side entry retaining is the combination of roadside support and support in the roadway. The new technology of gob-side entry retaining with gob-side fill and roof-cutting pressure relief was introduced, including the principle of pressure relief, the method and parameters of roof cutting, and the support method in the roadway after roof cutting and its engineering application, etc. The work has expounded the new research achievements on gob-side entry retaining in China recently, e.g., the roof-cutting resistance and support resistance of the filling body, the interaction relationship between the filling body and surrounding rocks, stress deformation characteristics, roof-cutting pressure relief, and the surrounding rock activity of the roof-cutting pressure relief of gob-side entry retaining and its interaction with the supporting body. Technical and scientific problems of gob-side entry retaining were pointed out in roadside support and support in a roadway in China. Suggestions for the future development of China's technology along the empty alley were proposed from support design, surrounding rock control, research methods, and technical equipment.