High-grade highways deformation and failure laws in mining area – a case in Nantun Coal Mine, China

Abstract

ABSTRACTHigh-grade highways constitute an important transportation infrastructure in coal mine areas in China. The surface subsidence caused by coal mining under high-grade highways poses a serious threat to the safety of high-grade highways. It is imperative to study the influence of mining-induced surface subsidence on high-grade highways. Zouji high-grade highways connect Zoucheng city and Jining city and pass over Nantun Coal Mine. Hence, coal resource exploitation in Nantun Coal Mine negatively affects high-grade highways. The 7328 working face belongs to the upper layers of No. 3 coal of Nantun Coal Mine. A field survey of deformation monitoring points above No. 7328 working face and a field investigation of high-grade highways damage area are performed to examine the subsidence relationship between high-grade highways pavement and surface, high-grade highways deformation and failure characteristics. The results are as follows: (1) the pavement subsidence is essentially consistent with the surface subsidence. When the pavement produces an uplift, the pavement subsidence is lower than surface subsidence. (2) Due to the discontinuous deformation of uplifts and cracks, the inclination curves exhibit obvious fluctuations. (3) The pavement cracks occur in the tensile area. The generation and development of pavement cracks mainly occur prior to the working face advances under the high-grade highways. Advances in working face increases the surface movement and deformation although the cracks width exhibits only a slight change. (4) The pavement uplifts occur in the compression deformation zone. The measured uplift height is between 5 and 15 cm, the length is between 5 and 12 m and the width is between 2 and 9 m. The horizontal profile of uplift generally corresponds to a long and narrow oval. (5) Given a strong stiffness and anti-deformation ability, the kerb also experiences compression failure within 24 h, and this mainly includes folding fracture or comminuted fracture. It is expected that the results of the study can guide coal exploitation under Zouji high-grade highways and provide an experimental reference for coal exploitation under high-grade highways in other mining areas.