Mining induced pressures are strong and overburden failure areas are large in top coal caving longwall mining, which constrains high production and safety mining. By employing the combination of the full view borehole...Mining induced pressures are strong and overburden failure areas are large in top coal caving longwall mining, which constrains high production and safety mining. By employing the combination of the full view borehole photography technique and the seismic CT scanner technique, the deformation and failure of overlying strata of fully mechanized caving face in shallow coal seam were studied and the failure development of overburden was determined. Results show that the full view borehole photography can reveal the characteristics of strata, and the seismic CT scanner can reflect the characteristics of strata between the boreholes. The combined measurement technique can effectively determine the height of fractured and caved zones. The top end of the caved zone in Yangwangou coal mine employing the top coal caving longwall mining was at the depth of 171 m and fractured zone was at the depth of 106-110 m. The results provide a theoretic foundation for controlling the overburden strata in the shallow buried top coal caving panel.展开更多
Tunnel construction opportunities involving shallow overburdens under difficult(e.g.,soft,unconsolidated)grounds have been increasing in Japan.Various auxiliary methods for excavating mountain tunnels have been develo...Tunnel construction opportunities involving shallow overburdens under difficult(e.g.,soft,unconsolidated)grounds have been increasing in Japan.Various auxiliary methods for excavating mountain tunnels have been developed and can satisfy stringent construction requirements.The ground improvement method,which is one of the auxiliary methods for shallow overburden tunnels,has demonstrated its ability to effectively control the amount of settlement under soft ground.However,the mechanism of the ground improvement method has not been clarified,nor has a suitable design code been established for it.Therefore,because the strength of the improved ground and the suitable length and width of the improved area have not been fully understood,an empirical design has been applied in every case.In this paper,the mechanical behavior during the excavation,including that of the stabilized ground,is evaluated through trapdoor experiments and numerical analyses.In addition,the enhancement of tunnel stability resulting from the application of the ground improvement method is discussed.展开更多
基金provided by the National Natural Science Foundation of China(No.51674132)the State Key Research Development Program of China(No.2016YFC0801407-2)+3 种基金the Research Fund of The State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.SKLCRSM15KF04)Natural Science Foundation of Liaoning Province(No.2015020614)Liaoning BaiQianWan Talents Program(No.201575)the Research Fund of State and Local Joint Engineering Laboratory for Gas Drainage & Ground Control of Deep Mines(Henan Polytechnic University)(No.G201602)
文摘Mining induced pressures are strong and overburden failure areas are large in top coal caving longwall mining, which constrains high production and safety mining. By employing the combination of the full view borehole photography technique and the seismic CT scanner technique, the deformation and failure of overlying strata of fully mechanized caving face in shallow coal seam were studied and the failure development of overburden was determined. Results show that the full view borehole photography can reveal the characteristics of strata, and the seismic CT scanner can reflect the characteristics of strata between the boreholes. The combined measurement technique can effectively determine the height of fractured and caved zones. The top end of the caved zone in Yangwangou coal mine employing the top coal caving longwall mining was at the depth of 171 m and fractured zone was at the depth of 106-110 m. The results provide a theoretic foundation for controlling the overburden strata in the shallow buried top coal caving panel.
文摘Tunnel construction opportunities involving shallow overburdens under difficult(e.g.,soft,unconsolidated)grounds have been increasing in Japan.Various auxiliary methods for excavating mountain tunnels have been developed and can satisfy stringent construction requirements.The ground improvement method,which is one of the auxiliary methods for shallow overburden tunnels,has demonstrated its ability to effectively control the amount of settlement under soft ground.However,the mechanism of the ground improvement method has not been clarified,nor has a suitable design code been established for it.Therefore,because the strength of the improved ground and the suitable length and width of the improved area have not been fully understood,an empirical design has been applied in every case.In this paper,the mechanical behavior during the excavation,including that of the stabilized ground,is evaluated through trapdoor experiments and numerical analyses.In addition,the enhancement of tunnel stability resulting from the application of the ground improvement method is discussed.
