In order to study stability control methods for a deep gate group under complex stresses,we conducted field investigations and analyses of reasons for damage in the Xuzhou mining district.Three reasons are proposed:de...In order to study stability control methods for a deep gate group under complex stresses,we conducted field investigations and analyses of reasons for damage in the Xuzhou mining district.Three reasons are proposed:deep high stress,improper roadway layout and support technology.The stability control countermeasures of the gate group consist of an intensive design technology and responding bolt-mesh-anchor truss support technology.Our research method has been applied at the -1000 m level gate group in Qishan Coal Mine.Suitable countermeasures have been tested by field monitoring.展开更多
Underground energy and resource development,deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances.An ...Underground energy and resource development,deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances.An evaluation method of the global stability coefficient of underground caverns based on static overload and dynamic overload was proposed.Firstly,the global failure criterion for caverns was defined based on its band connection of plastic-strain between multi-caverns.Then,overloading calculation of the boundary geostress and seismic intensity on the caverns model was carried out,and the critical unstable state of multi-caverns can be identified,if the plastic-strain band appeared between caverns during these overloading processes.Thus,the global stability coefficient for the multi-caverns under static loading and earthquake was obtained based on the corresponding overloading coefficient.Practical analysis for the Yingliangbao(YLB)hydraulic caverns indicated that this method can not only effectively obtain the global stability coefficient of caverns under static and dynamic earthquake conditions,but also identify the caverns’high-risk zone of local instability through localized plastic strain of surrounding rock.This study can provide some reference for the layout design and seismic optimization of underground cavern group.展开更多
A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the descript...A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the description leads us to consider positive homogeneous dynamical systems, establishing conditions for the stationary state existence and its local stability. A fourth pre-reproductive stage was considered, i.e. males and females spend part of their lives before being in condition to reproduce, as a first step to consider more general models. Finally, we parametrized the proposed model using southern elephant seal data, to analyze the direct applicability to a real population.展开更多
基金Projects 50490270 supported by the National Natural Science Foundation of ChinaProjects 2006CB202200 by the National Basic Research Program of ChinaProjects IRT0656 by the Innovation Term Project of the Ministry of Education of China
文摘In order to study stability control methods for a deep gate group under complex stresses,we conducted field investigations and analyses of reasons for damage in the Xuzhou mining district.Three reasons are proposed:deep high stress,improper roadway layout and support technology.The stability control countermeasures of the gate group consist of an intensive design technology and responding bolt-mesh-anchor truss support technology.Our research method has been applied at the -1000 m level gate group in Qishan Coal Mine.Suitable countermeasures have been tested by field monitoring.
基金Project(2023YFC2907204)supported by the National Key Research and Development Program of ChinaProject(52325905)supported by the National Natural Science Foundation of ChinaProject(DJ-HXGG-2023-16)supported by the Key Technology Research Projects of Power China。
文摘Underground energy and resource development,deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances.An evaluation method of the global stability coefficient of underground caverns based on static overload and dynamic overload was proposed.Firstly,the global failure criterion for caverns was defined based on its band connection of plastic-strain between multi-caverns.Then,overloading calculation of the boundary geostress and seismic intensity on the caverns model was carried out,and the critical unstable state of multi-caverns can be identified,if the plastic-strain band appeared between caverns during these overloading processes.Thus,the global stability coefficient for the multi-caverns under static loading and earthquake was obtained based on the corresponding overloading coefficient.Practical analysis for the Yingliangbao(YLB)hydraulic caverns indicated that this method can not only effectively obtain the global stability coefficient of caverns under static and dynamic earthquake conditions,but also identify the caverns’high-risk zone of local instability through localized plastic strain of surrounding rock.This study can provide some reference for the layout design and seismic optimization of underground cavern group.
文摘A mathematical model is presented in order to describe the dynamics of polygamous populations, bearing in mind single individuals of both sexes and the development of reproductive groups. In this context, the description leads us to consider positive homogeneous dynamical systems, establishing conditions for the stationary state existence and its local stability. A fourth pre-reproductive stage was considered, i.e. males and females spend part of their lives before being in condition to reproduce, as a first step to consider more general models. Finally, we parametrized the proposed model using southern elephant seal data, to analyze the direct applicability to a real population.
