Coal resources have always been the focus of attention in the field of sustainable development. Based on the problem of surrounding rock control in close-distance coal seams, first, a mechanical model of floor failure was established based on the 29204 working face in Dongqu Mine; the failure mechanism of the floor was revealed by the zero displacement line, and a method to judge the occurrence state of the roof in the lower coal seam was put forward. Furthermore, by FLAC3D numerical simulation software, the mechanical model is verified, and the optimal support parameters are optimized, and the optimal water–cement ratio and grouting pressure are determined to be 0.6 and 3 MPa respectively. The application shows that the roof displacement is reduced by about 73.48% compared with the control group. Compared with the control group, the cable stress decreased by about 50.68%, and the application effect is remarkable. The research results provide an effective solution to ensure the sustainable development of coal resources and disaster prevention.
In China, soft rock roof makes up the majority of coal mine roof, yet it is easy to break due to low strength and poor integrity. As such, it is difficult for the traditional pillar-based roadway protection means and pillarless mining techniques to effectively control the roadway roof. In order to solve the problems with pillarless mining under soft rock roof conditions, using the 1510 working face of Xinyi Coal Mine as an example, a gob-side caving roadway forming (GSCRF) technique for broken immediate roof is developed. This paper discusses the adaptability and feasibility of this technology through theoretical modeling and on-site engineering testing. A roadway rock surrounding control scheme based on “cable + steel beams + yielding prop” is further designed, and field tests and monitoring are carried out. Field tests show that, during GSCRF of the 1510 working face, the maximum subsidence of the roof remains within 200 mm. The convergence of the two sides causes stabilization. The tension on the anchor cables is gradually becoming stable. The monitoring results show that the roadway has a good stress environment and the surrounding rock is effectively controlled. Compared with the traditional pillarless mining mode, this technology has the technical advantages of achieving complete elimination of coal pillars, reduced pressure on the roadway roof, and interference-free mining of the working face. The research outcome can provide useful reference for pillarless mining by GSCRF and a solution for pillarless mining under soft rock roof conditions.
Aiming at the complex situation of mine underground engineering, this paper is chaos optimization to design 3D visualization simulation system of mine underground engineering, especially to satisfy the basic functions of 3D dynamic system and chaos optimization algorithm. A symmetric manifold algorithm is adopted. Explanations, transformation methods, and projective transformation methods and optical processing and conventional vector calculation techniques are used for analyzing underground mining engineering cases; it can be seen as follows: chaos-optimized symmetric variety algorithms in real life as an example. It can offer new ideas for optimizing the composition of underground mining engineering.
Aiming at the problems of difficult support of mining roadway under goaf of the close distance coal seam, obvious large deformation, and long-term continuous deformation of surrounding rock, an advanced bolt-grouting support system is proposed. The system can effectively solve the problem of roadway support from the design system, construction system, and monitoring and evaluation system, and realize the intelligent evaluation of bolt-grouting support. Based on the actual engineering background of 29204 working face in Dongqu Coal Mine, the supporting material and scheme, grouting parameters, and construction technology are studied and analyzed. Finally, the supporting scheme is adjusted and optimized timely by combining with the intelligent evaluation system of anchor grouting. The field practice results show that the advanced bolting-grouting support system has good applicability to roadway deformation under different conditions. The maximum subsidence of the roof in the test section is reduced by 73.48 % compared with the original support scheme, and the maximum stress of the anchor cable is reduced by 50.68 %. The research results provide a set of safe and effective support system and feasible technical ideas and methods to solve the problem of surrounding rock control of mining roadway under goaf of the close distance coal seam.
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