Strength and Cost Analysis of New Steel Sets as Roadway Support Project in Coal Mines

Abstract

Roadway support in swelling soft rocks in coal mines has become a critical challenge in recent years. For deformation control in swelling soft rocks, high strength sets are preferred in sites. But high strength always means high costs. Therefore, higher strength sets with not too much cost will be more welcomed in situ. Based on this, three new sets, including a floor beam set, a roof + floor beams set, and a roof + floor beams + braces set, have been developed in the present research. Strength comparisons and costs comparisons have been conducted in this research. Results illustrate that compared with the original set, in the floor beam set, the relative strength of bottom corners reaches 2.964, while the relative cost reaches 1.294; compared with the original set, in the roof + floor beams set, the relative strength of the top arch reaches 2.345, while the relative strength of bottom corners reaches 2.964, and the relative cost reaches 1.568; and compared with the original set, in the roof + floor beams + braces set, the relative strength of the top arch reaches 2.635, and the relative strength of bottom corners reaches 5.905, but the relative cost reaches 1.930. Floor beam set and roof + floor beams set illustrate higher strength and not too higher costs than the original set. Although the roof + floor beams + braces set exhibit much higher strength, they also demonstrate much higher costs than the original set. These new sets can be chosen according to different geological conditions in situ.

Numerical Simulation Analysis of New Steel Sets Used for Roadway Support in Coal Mines

“…In this section, we will verify the numerical model by comparing it with the calculated results [35]. As shown in Figure 6, a vertical downward concentrated load of 10 KN is applied to the top of the top arch, a horizontal to the right concentrated load of 10 KN is applied to the left bottom corner, and a horizontal to the left concentrated load of 10 KN is applied to the right bottom corner.…”

Impact of Depressurizing Boreholes on Energy Dissipation in Deep Roadway

“…The end-step Q and the loop-step m can be defined, and the initial stress σ i I of each cell grid is captured before the operation. Then, the operation is started and the new stress σ i N and strain increment Δε i are captured again after time-steps m. After that, the elastic energy and dissipated energy are calculated by equations ( 4) and (5). The whole loop will continue until the end-steps Q.…”

“…As a result, the roadway is prone to nonlinear large deformation, which leads to the rock burst, coal and gas outburst, or other dynamic disasters in serious cases [2][3][4]. The instability events still occur in coal mines even when measures were implemented in the field, including increasing support strength and repairing large deformed roadway more times [5][6][7][8]. Hence, how to effectively control the deep roadway stability is still a major issue that affects the safety of recovering the deep coal resources [9].…”

Supporting Design Optimization of Tunnel Boring Machines-Excavated Coal Mine Roadways: A Case Study in Zhangji, China

“…Therefore, these roadways need reinforcement and support to ensure the safety of excavation works. Much research has proposed the optimization of coal mine roadway support design based on the results of numerical simulation or in-situ monitoring [11]. Based on the simulation results of FLAC3D, Wang proposed full cross-section anchor-grouting reinforcement technology and applied it in underground coal mine roadways with loose and fractured surrounding rocks based on simulation results of FLAC3D, while Cao resolved the problems of lateral wall collapse and severe floor heaving in roadway support involving fractured rock layers [12,13].…”