Analysis of Roof Stability of Coal Roadway Heading Face

Abstract

One of the challenges that urgently needs to be addressed, both in current times and in the future, is to improve the heading speed of coal roadways. The roof instability of the heading face is the main factor restricting the rapid heading of coal roadways. Based on the theory of thin plate, a mechanical model of the roof in the heading face is established, the distribution law of deflection, stress, and internal force is discussed, and the supporting principle of the roof is clarified. Through a Flac3D numerical simulation, the main influencing factors of roof stability in the heading face are analyzed, including ground stress, surrounding rock strength, roadway section, unsupported distance, etc., and the regression analysis of each factor is carried out by evaluating the amount of roof subsidence. The results show that the maximum tensile stress and the corresponding bending moment of the roof appear at the fixed supported edge, and the maximum compressive stress and the maximum value of the corresponding bending moment appear at the center of the roof slightly close to the simply supported edge. In the on-site construction process, the position close to the fixed supported edge needs to be supported first. The roof subsidence has a positive exponential relationship with the stress level, a negative exponential relationship with the surrounding rock strength, a quadratic functional relationship with the roadway section, and a logarithmic relationship with the unsupported distance. In fractional support, the initial partial support can timely reduce the roof span and partially recover the confining pressure. Under certain geological and production conditions, the use of fractional support can not only effectively maintain the stability of the roadway but also speed up the heading speed. According to the research results, it is determined that in the auxiliary transportation roadway of the Caojiatan Coal Mine, the 122,110 working face adopts the fractional support model, the maximum roof subsidence is 18 mm, the roof is stable, and the monthly progress is more than 1000 m, which significantly improves the roadway heading speed.

Multifactor analysis of roof deformation and reasonable determination of the unsupported distance of a coal roadway heading face based on response surface method

“…The total length of new roadways in China is more than 12,000 km/year, and the safe and rapid tunneling of underground roadways is required for efficient coal mining 1–3 . Roadway heading and supporting technologies have developed rapidly in recent years.…”

“…The total length of new roadways in China is more than 12,000 km/year, and the safe and rapid tunneling of underground roadways is required for efficient coal mining. [1][2][3] Roadway heading and supporting technologies have developed rapidly in recent years. Current commonly used coal roadway heading and supporting technology can be roughly divided into three types [4][5][6][7] : (i) continuous shearer and anchor trolley cross displacement tunneling; (ii) excavation and anchor unit integration tunneling; and (iii) cantilever tunneling machine and single drilling rig or anchor trolley combined tunneling.…”

Collaborative optimization of driving support technology in the W3233 working face return airway

“…The progress in design concepts for open stopes and stopes with caving of the roof strata is illustrated. Su et al (2023) used a numerical simulation and response surface method to study the problems affecting roadway heading speed and roof stability. The supporting strength and driving speed under different supporting spacings were compared and analyzed to verify the feasibility of the method.…”