Aiming to get the strata behavior and stability rules of surrounding rock of the main return airway of Yushujing Coal Mine, convergence deformation of two sides and force of U-shaped steel yieldable support and bolt w...Aiming to get the strata behavior and stability rules of surrounding rock of the main return airway of Yushujing Coal Mine, convergence deformation of two sides and force of U-shaped steel yieldable support and bolt were monitored, and deformation of surrounding rock and mechanical characteristics of support structure were timely obtained to guide the informa- tion construction and optimize supporting parameters in water-rich soft rock roadway. The field monitoring results indicate the following. （1） Convergence displacement of rock surface increases with time continuity and shows surrounding rock＇s intense theological behavior. The original support scheme cannot control the large deformation and strongly theological behavior; （2） Without backfilling, the U-shaped steel support begins to bear load after erecting for 4-7 days and increases rapidly in the first 30 days. The U-shaped steel support at the right shoulder and top of roadway bears a larger force and the left side and shoulder bears a smaller force; （3） The stress of bolt increasing over time and at the right shoulder of roadway has larger growth and value. The mechanism of rock deformation and the failure and strata behavior in water-rich soft rock roadway are revealed based on the results of the measured relaxation zone of surrounding rock, measured stresses, and the rock mechanics tests.展开更多
The first topic discussed in this paper is to evaluate the present supporting theories,among which the typical two are collapse arch and elasto-plastic theories. The former is rather limited in practical application,a...The first topic discussed in this paper is to evaluate the present supporting theories,among which the typical two are collapse arch and elasto-plastic theories. The former is rather limited in practical application,and the latter is built up on some assumptions which is inconsis-tent with the reality,for it is of no need to support a roadway of which the surrounding rock is in elasto-plastic state. The second topic is to prove the objective existence of the broken zone in surrounding rock(BZSR) by a series of laboratory experiments and field measurements. The paper indicates that the object to be supported mainly is the bulking or expanding force resulted from the development of BZSR. This is remarkably different from the existing points of view which have been generally recognized nowadays. So far ,this theory has been tested in supporting more than ten thousand meters roadways located in various strata and has proved itself to have a great technoeconomical benefit.展开更多
The properties of broken rock before and after grouting reinforcement are studied. Testing results show that grouting can raise the residual strength of broken rock, and the broken rockness by grouting can keep the st...The properties of broken rock before and after grouting reinforcement are studied. Testing results show that grouting can raise the residual strength of broken rock, and the broken rockness by grouting can keep the steady supporting capacity within a relatively large deformation range. Revealing of the characteristics of stage deformation and damage process comes to the conclusion that the supporting of soft rock roadway should be analyzed in a dynamic view, and the grouting should be delayed at a proper occasion. Based on the above, the stepwise reinforcement technology characterized by immediate shotcreting, timely bolting and delay grouting is put forward and illustrated with a successful engineering practice.展开更多
Surrounding rock control in the overlying protective coal seam is a challenging topic for de-stressed mining of multi-seamed coal.Current research findings on roadway control were used in the design of a physical mode...Surrounding rock control in the overlying protective coal seam is a challenging topic for de-stressed mining of multi-seamed coal.Current research findings on roadway control were used in the design of a physical model of a complex textured roof having a varying thickness.The model was used to study roadway instability and collapse caused by dynamic pressure.The results show that when the thickness of the roof exceeds the bolted depth the roadway security is least and the roof has the greatest possibility for collapse.Numerical simulations were also carried out to study stress redistribution before and after roadway excavation during underlying protective seam mining.The evolution of roadway displacement and fracture,as affected by support methods,has been well studied.A series of support principles and technologies for mining affected roadways has been proposed after demonstration of successful practical application in the Huainan Mines.These principles and technologies are of extended value to deep coal mining support in China.展开更多
Based on a great number of measured data, the author put forward zonal com-pressive and tensile deformation mechanism of soft rock around roadway. By using self-supporting capacity of compressive zone and controlling ...Based on a great number of measured data, the author put forward zonal com-pressive and tensile deformation mechanism of soft rock around roadway. By using self-supporting capacity of compressive zone and controlling rock deformation of tensile zone, the long bolt or short bolt group supporting form was given for different size of rock compressive zone and tensile zone. Finally, studied on the determining method of rational support parameters of bolting and shotcreting with wire mesh in different support technol-ogy.展开更多
Numerical analysis of the optimal supporting time and long-term stability index of the surrounding rocks in the underground plant of Xiangjiaba hydro-power station was carried out based on the rheological theory. Firs...Numerical analysis of the optimal supporting time and long-term stability index of the surrounding rocks in the underground plant of Xiangjiaba hydro-power station was carried out based on the rheological theory. Firstly,the mechanical parameters of each rock group were identified from the experimental data; secondly,the rheological calculation and analysis for the cavern in stepped excavation without supporting were made; finally,the optimal time for supporting at the characteristic point in a typical section was obtained while the creep rate and displacement after each excavation step has satisfied the criterion of the optimal supporting time. Excavation was repeated when the optimal time for supporting was identified,and the long-term stability creep time and the maximum creep deformation of the characteristic point were determined in accordance with the criterion of long-term stability index. It is shown that the optimal supporting time of the characteristic point in the underground plant of Xiangjiaba hydro-power station is 5-8 d,the long-term stability time of the typical section is 126 d,and the corresponding largest creep deformation is 24.30 mm. While the cavern is supported,the cavern deformation is significantly reduced and the stress states of the surrounding rock masses are remarkably improved.展开更多
基金Supported by the Projects of National Natural Science Foundation （51174196） the Program for New Century Excellent Talents in University （NCET-07-0519）
文摘Aiming to get the strata behavior and stability rules of surrounding rock of the main return airway of Yushujing Coal Mine, convergence deformation of two sides and force of U-shaped steel yieldable support and bolt were monitored, and deformation of surrounding rock and mechanical characteristics of support structure were timely obtained to guide the informa- tion construction and optimize supporting parameters in water-rich soft rock roadway. The field monitoring results indicate the following. （1） Convergence displacement of rock surface increases with time continuity and shows surrounding rock＇s intense theological behavior. The original support scheme cannot control the large deformation and strongly theological behavior; （2） Without backfilling, the U-shaped steel support begins to bear load after erecting for 4-7 days and increases rapidly in the first 30 days. The U-shaped steel support at the right shoulder and top of roadway bears a larger force and the left side and shoulder bears a smaller force; （3） The stress of bolt increasing over time and at the right shoulder of roadway has larger growth and value. The mechanism of rock deformation and the failure and strata behavior in water-rich soft rock roadway are revealed based on the results of the measured relaxation zone of surrounding rock, measured stresses, and the rock mechanics tests.
文摘The first topic discussed in this paper is to evaluate the present supporting theories,among which the typical two are collapse arch and elasto-plastic theories. The former is rather limited in practical application,and the latter is built up on some assumptions which is inconsis-tent with the reality,for it is of no need to support a roadway of which the surrounding rock is in elasto-plastic state. The second topic is to prove the objective existence of the broken zone in surrounding rock(BZSR) by a series of laboratory experiments and field measurements. The paper indicates that the object to be supported mainly is the bulking or expanding force resulted from the development of BZSR. This is remarkably different from the existing points of view which have been generally recognized nowadays. So far ,this theory has been tested in supporting more than ten thousand meters roadways located in various strata and has proved itself to have a great technoeconomical benefit.
文摘The properties of broken rock before and after grouting reinforcement are studied. Testing results show that grouting can raise the residual strength of broken rock, and the broken rockness by grouting can keep the steady supporting capacity within a relatively large deformation range. Revealing of the characteristics of stage deformation and damage process comes to the conclusion that the supporting of soft rock roadway should be analyzed in a dynamic view, and the grouting should be delayed at a proper occasion. Based on the above, the stepwise reinforcement technology characterized by immediate shotcreting, timely bolting and delay grouting is put forward and illustrated with a successful engineering practice.
基金Financial support for this work,provided by the National Key Technology R&D Program(No.2007BAK28B00)the National Natural Science Foundation for the Youth of China(No.50904064)+2 种基金the Research Fund for the Youth of China University of Mining & Technology(No.2008A004)the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.SKLCRSM09X03)the Research Fund of the State Key Laboratory of Coal Resources and Mine Safety,CUMT(No.08KF10)
文摘Surrounding rock control in the overlying protective coal seam is a challenging topic for de-stressed mining of multi-seamed coal.Current research findings on roadway control were used in the design of a physical model of a complex textured roof having a varying thickness.The model was used to study roadway instability and collapse caused by dynamic pressure.The results show that when the thickness of the roof exceeds the bolted depth the roadway security is least and the roof has the greatest possibility for collapse.Numerical simulations were also carried out to study stress redistribution before and after roadway excavation during underlying protective seam mining.The evolution of roadway displacement and fracture,as affected by support methods,has been well studied.A series of support principles and technologies for mining affected roadways has been proposed after demonstration of successful practical application in the Huainan Mines.These principles and technologies are of extended value to deep coal mining support in China.
文摘Based on a great number of measured data, the author put forward zonal com-pressive and tensile deformation mechanism of soft rock around roadway. By using self-supporting capacity of compressive zone and controlling rock deformation of tensile zone, the long bolt or short bolt group supporting form was given for different size of rock compressive zone and tensile zone. Finally, studied on the determining method of rational support parameters of bolting and shotcreting with wire mesh in different support technol-ogy.
基金Projects(50911130366, 50979030) supported by the National Natural Science Foundation of ChinaProject(2008BAB29B01) supported by the National Key Technology R&D Program of China
文摘Numerical analysis of the optimal supporting time and long-term stability index of the surrounding rocks in the underground plant of Xiangjiaba hydro-power station was carried out based on the rheological theory. Firstly,the mechanical parameters of each rock group were identified from the experimental data; secondly,the rheological calculation and analysis for the cavern in stepped excavation without supporting were made; finally,the optimal time for supporting at the characteristic point in a typical section was obtained while the creep rate and displacement after each excavation step has satisfied the criterion of the optimal supporting time. Excavation was repeated when the optimal time for supporting was identified,and the long-term stability creep time and the maximum creep deformation of the characteristic point were determined in accordance with the criterion of long-term stability index. It is shown that the optimal supporting time of the characteristic point in the underground plant of Xiangjiaba hydro-power station is 5-8 d,the long-term stability time of the typical section is 126 d,and the corresponding largest creep deformation is 24.30 mm. While the cavern is supported,the cavern deformation is significantly reduced and the stress states of the surrounding rock masses are remarkably improved.
