Blast pressure measurements of a controlled underwater explosion in the sea were carried out.An explosive of 25-kg trinitro-toluene(TNT)equivalent was detonated,and the blast pressures were recorded by eight diferent ...Blast pressure measurements of a controlled underwater explosion in the sea were carried out.An explosive of 25-kg trinitro-toluene(TNT)equivalent was detonated,and the blast pressures were recorded by eight diferent high-performance pressure sensors that work at the nonresonant high-voltage output in adverse underwater conditions.Recorded peak pressure values are used to establish a relationship in the well-known form of empirical underwater explosion(UNDEX)loading formula.Constants of the formula are redetermined by employing the least-squares method in two diferent forms for best ftting to the measured data.The newly determined constants are found to be only slightly diferent from the generally accepted ones.展开更多
Blast pressure of C-H-O solvents on failed lithium-ion cells at the voltage range between 3.8 V and 4.18 V may be calculated by means of the simple semi-empirical equation, y = （Ia ＋ Jb）/（Ka ＋ Lb ＋ Me）, p is th...Blast pressure of C-H-O solvents on failed lithium-ion cells at the voltage range between 3.8 V and 4.18 V may be calculated by means of the simple semi-empirical equation, y = （Ia ＋ Jb）/（Ka ＋ Lb ＋ Me）, p is the initial density of solvent, Q is the chemical energy of explosion, v is the voltage. The values of a, b, c depend on C-H-O composition. Value of I, J, K, L, Mmay be estimated from the H20-CO2 arbitrary decomposition assumption. Blast pressure derived in this manner can provide preliminary protective estimation and it is compared with experiment results by adiabatic calorimeter.展开更多
Mitigation of blast pressure using water in a walled container was evaluated. A PETN （pentaerythritol tetranitrate） pellet of 1.4 g near the model wall was detonated on a steel plate. A water-filled container was pl...Mitigation of blast pressure using water in a walled container was evaluated. A PETN （pentaerythritol tetranitrate） pellet of 1.4 g near the model wall was detonated on a steel plate. A water-filled container was placed between the explosive and the wall. The pressure histories at six points, which corresponded to Hopkinson scaled distance of from 3.6 m·kg^-1/3 to 21.7 m·kg^-1/3 were evaluated along with dependence of mitigation effects on the amount of water and the position of the container. The presence of the water and the wall mitigated the peak overpressure near the explosion points and the positive impulse along all points. The mitigation effect was equivalent to 20-30% reduction of explosive weight based on discussion of the equivalent ratio. The presence of the water along the wall （not very close to the explosive） also mitigated the blast pressure.展开更多
Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researche...Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researches on partial relieving pressure were completed for the entry with U-steel arched yielding support. The relieving pressure parameters, technology process and results of springing blasting by boreholes and excavating pockets in the two sides of entry were introduced. It is demonstrated that springing will not be shaped under the condition of single borehole arrangement after exploded, the arrangement by a group, it will make borehole bottom form springing in 0.6-0.8 m in diameter, that convergence of two sides and roof to floor have some increments by using springing blasting for reliving pressure. This kind of method for reliving pressure is not suitable to use in the deep mine, and that the convergence of two sides obviously declined by excavating pocket in two sides, it can be still used in the entry with metal support, while maintenance of entry in deep mines is difficult, and can not be supported by bolt or bolt with wire mesh.展开更多
Two large explosion trials (5 000 kg TNT and 500 kg ANFO) were conducted in Woomera, Australia in April/May 2006. Advance Protective Technologies for Engineering Structures (APTES) group tested 2 large single-storey c...Two large explosion trials (5 000 kg TNT and 500 kg ANFO) were conducted in Woomera, Australia in April/May 2006. Advance Protective Technologies for Engineering Structures (APTES) group tested 2 large single-storey concrete modules with individual components such as doors, windows and tiled panels. A description of the trial and details of various modules tested in these trials are presented in the paper. Numerical modelling and simulations are performed using computer programs, CONWEP, AIR3D and AUTODYN. A comparison of the pressure time histories obtained using these codes is made along with the concluding remarks.展开更多
文摘Blast pressure measurements of a controlled underwater explosion in the sea were carried out.An explosive of 25-kg trinitro-toluene(TNT)equivalent was detonated,and the blast pressures were recorded by eight diferent high-performance pressure sensors that work at the nonresonant high-voltage output in adverse underwater conditions.Recorded peak pressure values are used to establish a relationship in the well-known form of empirical underwater explosion(UNDEX)loading formula.Constants of the formula are redetermined by employing the least-squares method in two diferent forms for best ftting to the measured data.The newly determined constants are found to be only slightly diferent from the generally accepted ones.
文摘Blast pressure of C-H-O solvents on failed lithium-ion cells at the voltage range between 3.8 V and 4.18 V may be calculated by means of the simple semi-empirical equation, y = （Ia ＋ Jb）/（Ka ＋ Lb ＋ Me）, p is the initial density of solvent, Q is the chemical energy of explosion, v is the voltage. The values of a, b, c depend on C-H-O composition. Value of I, J, K, L, Mmay be estimated from the H20-CO2 arbitrary decomposition assumption. Blast pressure derived in this manner can provide preliminary protective estimation and it is compared with experiment results by adiabatic calorimeter.
文摘Mitigation of blast pressure using water in a walled container was evaluated. A PETN （pentaerythritol tetranitrate） pellet of 1.4 g near the model wall was detonated on a steel plate. A water-filled container was placed between the explosive and the wall. The pressure histories at six points, which corresponded to Hopkinson scaled distance of from 3.6 m·kg^-1/3 to 21.7 m·kg^-1/3 were evaluated along with dependence of mitigation effects on the amount of water and the position of the container. The presence of the water and the wall mitigated the peak overpressure near the explosion points and the positive impulse along all points. The mitigation effect was equivalent to 20-30% reduction of explosive weight based on discussion of the equivalent ratio. The presence of the water along the wall （not very close to the explosive） also mitigated the blast pressure.
基金Supported by the Key Project of the National Natural Science Foundation （50490273）
文摘Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researches on partial relieving pressure were completed for the entry with U-steel arched yielding support. The relieving pressure parameters, technology process and results of springing blasting by boreholes and excavating pockets in the two sides of entry were introduced. It is demonstrated that springing will not be shaped under the condition of single borehole arrangement after exploded, the arrangement by a group, it will make borehole bottom form springing in 0.6-0.8 m in diameter, that convergence of two sides and roof to floor have some increments by using springing blasting for reliving pressure. This kind of method for reliving pressure is not suitable to use in the deep mine, and that the convergence of two sides obviously declined by excavating pocket in two sides, it can be still used in the entry with metal support, while maintenance of entry in deep mines is difficult, and can not be supported by bolt or bolt with wire mesh.
文摘Two large explosion trials (5 000 kg TNT and 500 kg ANFO) were conducted in Woomera, Australia in April/May 2006. Advance Protective Technologies for Engineering Structures (APTES) group tested 2 large single-storey concrete modules with individual components such as doors, windows and tiled panels. A description of the trial and details of various modules tested in these trials are presented in the paper. Numerical modelling and simulations are performed using computer programs, CONWEP, AIR3D and AUTODYN. A comparison of the pressure time histories obtained using these codes is made along with the concluding remarks.
