Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the pas...Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the passive support to the initiative support, and the soft rock entry was supported.And its process is simple and less equipment is needed,and the cost is low and the advance rate is high,which can meet the require- ments of actual mining.It solves many support difficult problems.展开更多
The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct ...The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.展开更多
Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two dou...Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation （MSE） and uniform support excitation （USE）. In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the ＂overflow＂ mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.展开更多
对新能源多场站短路比(multiplerenewableenergy stations short circuit ratio,MRSCR)进行改进,提出一种实时临界短路比(critical short circuit ratio,CSCR)指标的求取方法,实现静态电压稳定性判别标准与临界短路比算法的统一。首先,...对新能源多场站短路比(multiplerenewableenergy stations short circuit ratio,MRSCR)进行改进,提出一种实时临界短路比(critical short circuit ratio,CSCR)指标的求取方法,实现静态电压稳定性判别标准与临界短路比算法的统一。首先,基于MRSCR的定义分析其优缺点及适用性,在此基础上结合所提出的计及新能源出力特性的扩展雅可比矩阵,得到了新能源多场站临界短路比的求取方法;其次,理论分析了MRSCR在不同因素影响下的变化规律;最后,依托电力系统全数字仿真装置(advanced digital power system simulator,ADPSS)对新能源多场站临界短路比的准确性和有效性以及MRSCR的影响因素进行了仿真验证。仿真结果表明,所提临界短路比能够准确判定系统的临界稳定状态,评估失稳风险,且减小动态感应电动机比重、增加并联电容器容量、新能源并网点位置靠近系统侧均对MRSCR的提升有显著效果。展开更多
基金the Educational Department of Liaoning Province(20081220)
文摘Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the passive support to the initiative support, and the soft rock entry was supported.And its process is simple and less equipment is needed,and the cost is low and the advance rate is high,which can meet the require- ments of actual mining.It solves many support difficult problems.
基金supported by Distinguished Youth Funds of National Natural Science Foundation of China (No.51925402)National Natural Science Foundation of China (Nos.51904203 and 52174125)+4 种基金the China Postdoctoral Science Foundation (No.2021M702049)the Tencent Foundation or XPLORER PRIZEShanxi Science and Technology Major Project Funds (No.20201102004)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering (No.2021SX-TD001)Open Fund Research Project Supported by State Key Laboratory of Strata Intelligent Control and Green Mining Co-founded by Shandong Province and the Ministry of Science and Technology (No.SICGM202209)。
文摘The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.
文摘Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation （MSE） and uniform support excitation （USE）. In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the ＂overflow＂ mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.
文摘对新能源多场站短路比(multiplerenewableenergy stations short circuit ratio,MRSCR)进行改进,提出一种实时临界短路比(critical short circuit ratio,CSCR)指标的求取方法,实现静态电压稳定性判别标准与临界短路比算法的统一。首先,基于MRSCR的定义分析其优缺点及适用性,在此基础上结合所提出的计及新能源出力特性的扩展雅可比矩阵,得到了新能源多场站临界短路比的求取方法;其次,理论分析了MRSCR在不同因素影响下的变化规律;最后,依托电力系统全数字仿真装置(advanced digital power system simulator,ADPSS)对新能源多场站临界短路比的准确性和有效性以及MRSCR的影响因素进行了仿真验证。仿真结果表明,所提临界短路比能够准确判定系统的临界稳定状态,评估失稳风险,且减小动态感应电动机比重、增加并联电容器容量、新能源并网点位置靠近系统侧均对MRSCR的提升有显著效果。
