Evolution of Interior and Exterior Bearing Structures of the Deep-Soft-Rock Roadway: From Theory to Field Test in the Pingdingshan Mining Area

Abstract

Pingdingshan mining area is one of the typical deep mining areas in China, and most of the mines in this area are troubled by the difficulties of the deep-soft-rock roadway support. Based on the concept of synergistic interactions of the interior and exterior bearing structure of the surrounding rock and, considering the specific geological conditions of the research site, we establish the mechanical model of the interior and exterior bearing structure of the roadway. Based on numerical simulation, we reveal the influence of main factors, such as support strength and mechanical characteristics, of surrounding rock on the distribution and evolution of the interior and exterior bearing structure. We found that increasing the support strength and mechanical parameters of surrounding rock can make the exterior bearing structure close to the roadway enhance the bearing characteristics of the interior and exterior bearing structure and improve the roadway stability. The distribution characteristics of the interior and exterior bearing structure of the roadway under six different support strengths and six different grouting parameters were systematically investigated by field measurements. According to the field test results, an effective strategy for controlling the deep-soft-rock roadway is proposed, which provides a good reference for surrounding rock control of the deep-soft-rock roadway in the Pingdingshan mining area and mines with similar mining conditions.

Mechanism of Time-Dependent Instability of Deep Soft-Rock Roadway and Crack-Filling Reinforcement Technology

“…After roadway excavation, the plastic damage degree and range of the surrounding rock both increase, and the soft surrounding rock is prone to overall roof subsidence, rib bulge, and floor structural rheology. Statistics found that 90% of underground deep soft-rock roadways have been repaired at least once [3][4][5][6]. Considering the stability of the roadway surrounding rock, it is of great significance to analyze the time-dependent damage of deep soft-rock roadways and propose effective support measures.…”

Large Deformation Characteristics of Surrounding Rock and Support Technology of Shallow-Buried Soft Rock Roadway: A Case Study

“…Rocks surrounding the coal seams are generally very weak [3,7]. Increasing mining depth due to high in-situ stress, high overburden, and tectonic stress causes the surrounding rock to undergo large nonlinear deformation [8], making it soft [9], e.g., the Pingdingshan mining area [10], Yili No. 1 Coal Mine [11], Xiaokang Coal Mine [12], Xin'an coal mine in Gansu Province [13,14].…”

Calculation of Stability Limit Displacement of Surrounding Rock of Deep-Buried Soft Rock Tunnel Construction Based on Fuzzy Logic Matching Algorithm

“…The stress concentration phenomenon after the excavation of the cavern in the deep and weak rock mass may cause the stress level of the rock mass to exceed the strength of the surrounding rock, forming a plastic stress area. Plastic shear slip or plastic flow tends to increase the risk of construction and threaten the quality and safety of the project [4][5][6][7][8]. Therefore, it is extremely necessary to calculate the stability limit displacement of surrounding rock for deep-buried soft rock tunnel construction [9][10][11][12].…”