In order to study the rules of distribution in a plastic zone of rocks, surrounding a roadway, affected by tectonic stress, we first analyzed the mechanics of a roadway affected by tectonic stress and derived a theore...In order to study the rules of distribution in a plastic zone of rocks, surrounding a roadway, affected by tectonic stress, we first analyzed the mechanics of a roadway affected by tectonic stress and derived a theoretical formula for the plastic zone of rocks surrounding a roadway. We also analyzed the distribution characteristics of the plastic zone under different levels of tectonic stress, vertical pressure, cohesion and friction angle of the surrounding rock. Secondly, we used numerical simulation to analyze the range and shape features of the plastic zone of rocks surrounding the roadway, given different tectonic stress levels. Finally we used a rock drilling detector to carry out field measurements on the broken state of rock surrounding the roadway at the –700 substation and channels in the Xinzhuang mine of the Shenhuo mining area. Given the measured ground stress, we analyzed the relationship between tectonic stress and the distribution of this plastic zone. Our results show that the range of the plastic zone at the top and bottom of the roadway increases with an increase in tectonic stress and this increase is especially obvious at the roadway corner.展开更多
A metal rod is used in the high temperature testing for ultrasonic propagation and heat output, but the trailing ech- oes generated by ultrasonic penetration through the metal rod seriously affect the recognition and ...A metal rod is used in the high temperature testing for ultrasonic propagation and heat output, but the trailing ech- oes generated by ultrasonic penetration through the metal rod seriously affect the recognition and extraction of characteristic signals. According to the phenomenon, the Finite Element Method （FEM） is used to analyze ultrasonic penetration through a metal rod, the reason of the trailing echoes and the regularity of ultrasonic signals. The motion equation of ultra- sonic propagation in a metal rod is established and calculated, then the simulation signals and instantaneous eartographies of the process are obtained. Based on the results of the analysis, it can be concluded that the intervals of the trailing echoes are de- termined by the rod＇ s diameter and wave velocity. In practical applications, the FEM is used to analyze ultrasonic propagation in the designed buffer rod at first. Based on the characteristics of the simulation signals, the material and dimension are ad- justed and selected, aiming to identify the characteristic echo and trailing echoes in time domain and extract characteristic echo from the ultrasonic signals available.展开更多
基金Financial support for this work, provided by the research fund of the State Key Laboratory of Coal Resources and Mine Safety of the China University of Mining & Technology (No.08kf11) is gratefully ac-knowledged
文摘In order to study the rules of distribution in a plastic zone of rocks, surrounding a roadway, affected by tectonic stress, we first analyzed the mechanics of a roadway affected by tectonic stress and derived a theoretical formula for the plastic zone of rocks surrounding a roadway. We also analyzed the distribution characteristics of the plastic zone under different levels of tectonic stress, vertical pressure, cohesion and friction angle of the surrounding rock. Secondly, we used numerical simulation to analyze the range and shape features of the plastic zone of rocks surrounding the roadway, given different tectonic stress levels. Finally we used a rock drilling detector to carry out field measurements on the broken state of rock surrounding the roadway at the –700 substation and channels in the Xinzhuang mine of the Shenhuo mining area. Given the measured ground stress, we analyzed the relationship between tectonic stress and the distribution of this plastic zone. Our results show that the range of the plastic zone at the top and bottom of the roadway increases with an increase in tectonic stress and this increase is especially obvious at the roadway corner.
基金supported by the National Natural Science Foundation of China(No.60672005)the Shanxi Provincial Foundation for Returned Scholars(Main Program),China(No.69)the Science Programof Shanxi Province,China(No.20110321029)
文摘A metal rod is used in the high temperature testing for ultrasonic propagation and heat output, but the trailing ech- oes generated by ultrasonic penetration through the metal rod seriously affect the recognition and extraction of characteristic signals. According to the phenomenon, the Finite Element Method （FEM） is used to analyze ultrasonic penetration through a metal rod, the reason of the trailing echoes and the regularity of ultrasonic signals. The motion equation of ultra- sonic propagation in a metal rod is established and calculated, then the simulation signals and instantaneous eartographies of the process are obtained. Based on the results of the analysis, it can be concluded that the intervals of the trailing echoes are de- termined by the rod＇ s diameter and wave velocity. In practical applications, the FEM is used to analyze ultrasonic propagation in the designed buffer rod at first. Based on the characteristics of the simulation signals, the material and dimension are ad- justed and selected, aiming to identify the characteristic echo and trailing echoes in time domain and extract characteristic echo from the ultrasonic signals available.
