Cooperative Control Mechanism of Efficient Driving and Support in Deep-Buried Thick Top-Coal Roadway: A Case Study

Abstract

For deep-buried thick top-coal roadways under high stress, there exists great difficulty in controlling the stability of the surrounding rock as well as in the necessity for low driving speeds. Taking the return air roadway 20201 (RAR 20201) of the Dahaize Coal Mine as the background, this paper presents a typical engineering case of a deep-buried thick top-coal roadway in a western mine. Through methods such as in situ investigation, theoretical analysis, numerical simulation and engineering practice, we studied the deformation and failure mechanisms of the surrounding rock in a deep-buried high-stress thick top-coal roadway, and revealed the driving speed effect. Results show that compared with shallow buried roadways, the deep-buried thick-roof coal roadway suffers a greater range of damage and failure. The roof damage is so deep that it exceeds the action range of bolts, resulting in the stress transferring to both sides, which affects the stability of the roadway surroundings. The curve of unloading disturbance stress produced by roadway head-on driving is in accordance with the “power exponential” composite function; that is, the faster the driving speed, the less unloading disturbance intensity that is exerted on the roof strata. This paper puts forward targeted cooperative control countermeasures of efficient driving and support in a deep-buried thick top-coal roadway. On one hand, the support efficiency of a single bolt is improved so as to reduce the overall support density; on the other hand, under low support density, the driving-supporting circulation efficiency is also accelerated so as to weaken the unloading disturbance and improve roadway formation speed. Engineering practice shows great control effect of the roadway surrounding rock, and the roadway formation speed is also greatly improved. This research can provide reference for efficient driving and support design in similar deep-buried thick top-coal roadways.

Failure properties of roadway with extra-thick coal seams and its control techniques

“…Based on the relevant research results, it is well known that the superimposed mining stress which induced by the large mining thickness of the coal seams and the intense movement of the overlying strata could aggravate the deformation and instability failure of the roadway with thick coal roof [ 4 ], the supporting system and its efficiency will gradually decrease [ 5 , 6 ] during this process, and the asymmetric floor heave and significant deformation was more easily appear for gob side roadway in extra-thick Coal Seams [ [7] , [8] , [9] ]. In order to control the surrounding rock deformation of the roadway with extra-thick coal seam, the dense combined supports have to be applied in roadway construction on site, which significantly reducing the driving efficiency and leading to the technical problem of mining proportion imbalance in the mine [ 10 ]. Meanwhile, the reasonable support technologies for roadway with extra-thick coal seam were extensively studied and proposed based on different geological condition, such as the high strength and high pre-stress bolt and diagonal cable and beam structure [ 2 ], the pressure relief anchor box beam [ [11] , [12] , [13] ] and the combining high prestress constant resistance support with roof-cutting technology [ 14 , 15 ] for deep roadway, the combined support method of “high prestressed long and short anchor cables” by double arch bearing structure [ 16 ], the integrated shed system used for the roadway in loose thick coal seam [ 17 ], the combined supporting technology of “coal wall water injection + metal roof frame” [ 18 ], the secondary support schemes called “grouting + I-steel support + bolt” and “grouting + U steel support + anchor + anchor cable” [ [19] , [20] , [21] ] and so on[ 22 ] .…”

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

“…This study explores a synergistic optimization method for support technology and roadway excavation to improve the efficiency of coal mine roadway mining and support reliability, reduce safety risks, and provide technical support for the sustainable development of coal mine production (Han, 2017;Hu et al, 2022;Wang, 2014). Based on the engineering practice of the Qianyingzi Mine, support schemes were explored through data collection, theoretical derivation, and numerical simulation (Hou, 2017;Wang, 2021).…”

Study on the Upper Limit of Roof Failure in Soft Rock Roadway

“…Jia et al [11,12] used FLAC 3D numerical simulation software to investigate roadway roofs containing coal seams of diferent thicknesses with low strength, identifying the primary causes of severe deformation of soft rock roadways. Li et al [13][14][15][16] determined the distribution pattern of the plastic zone of the surrounding rock of the roadway through theoretical analysis. In response to the failure characteristics of soft rock roadways, Zhao et al [17][18][19][20] examined the deformation mechanism of deep roadways and proposed a composite support technology for the surrounding rock.…”