The purpose of this study is to investigate the role of bolt profile configuration in load transfer capacity between the bolt and grout.Therefore,five types of rock bolts are used with different profiles.The rock bolt...The purpose of this study is to investigate the role of bolt profile configuration in load transfer capacity between the bolt and grout.Therefore,five types of rock bolts are used with different profiles.The rock bolts are modeled by ANSYS software.Models show that profile rock bolt T_3 and T_ with load capacity 180 and 195 kN in the jointed rocks,are the optimum profiles.Finally,the performances of the selected profiles are examined in Tabas Coal Mine by FLAC software.There is good subscription between the results of numerical modeling and instrumentation reading such as tells tale,sonic extensometer and strain gauge rock bolt.According to the finding of this study,the proposed pattern of rock bolts,on 7 + 6 patterns per meter with 2 flexi bolt(4 m) for support gate road.展开更多
Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination ...Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination of the support elements can be used to increase rock strength and minimise the displacement of unstable rock mass. It is important to understand how the support system works to ensure the stability of underground excavations. Cable bolts have been commonly used as an effective underground support system and an element of reinforcement to improve rock stability. Cable bolts are usually considered to be subjected to static loads under relatively low stress environments, however, in burst-prone conditions, they might be subjected to dynamic loads. Cable bolts as well as other support elements are used in burst-prone conditions to absorb the kinetic energy of the removed rock to avoid sudden and violent failures. This paper develops numerical and a novel analytical simulation technique for cable bolts to assess their structural behaviour under static and dynamic loading conditions. The numerical and analytical models are then validated against experimental observations reported in the literature, which demonstrates the reliability of the proposed models.展开更多
To study the tensile mechanical properties of constant resistance bolts, the RFPA(Rock Failure Process Analysis) statics software is used to perform a uniaxial tensile test on a constant resistance bolt. The numerical...To study the tensile mechanical properties of constant resistance bolts, the RFPA(Rock Failure Process Analysis) statics software is used to perform a uniaxial tensile test on a constant resistance bolt. The numerical test results show that the plastic strain value is 12 times the magnitude of the elastic strain. During plastic deformation, the fluctuation in the stress magnitude is relatively stable, indicating that the bolt has good constant resistance characteristics. The numerical test results are in good agreement with the laboratory test results of M.C. He, and the accuracy and reliability of the numerical test method are verified. Therefore, the RFPA software with coupled static-dynamic loading is further adopted to study the supporting effects of traditional bolts and constant resistance bolts under coupled staticdynamic loading. The numerical comparison of the test results show that the constant resistance bolts can effectively control the deformation amount and rate of the laneway surrounding rock, reduce the total and rate of increase in the accumulated acoustic emissions,decrease the stress on the units in the model and protect the stability of the laneway. This paper verifies that a constant resistance bolt has better impact resistance mechanical properties than those of a traditional bolt and provides an effective way to control rock burst and soft rock that is prone to large deformation damage.展开更多
文摘The purpose of this study is to investigate the role of bolt profile configuration in load transfer capacity between the bolt and grout.Therefore,five types of rock bolts are used with different profiles.The rock bolts are modeled by ANSYS software.Models show that profile rock bolt T_3 and T_ with load capacity 180 and 195 kN in the jointed rocks,are the optimum profiles.Finally,the performances of the selected profiles are examined in Tabas Coal Mine by FLAC software.There is good subscription between the results of numerical modeling and instrumentation reading such as tells tale,sonic extensometer and strain gauge rock bolt.According to the finding of this study,the proposed pattern of rock bolts,on 7 + 6 patterns per meter with 2 flexi bolt(4 m) for support gate road.
文摘Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination of the support elements can be used to increase rock strength and minimise the displacement of unstable rock mass. It is important to understand how the support system works to ensure the stability of underground excavations. Cable bolts have been commonly used as an effective underground support system and an element of reinforcement to improve rock stability. Cable bolts are usually considered to be subjected to static loads under relatively low stress environments, however, in burst-prone conditions, they might be subjected to dynamic loads. Cable bolts as well as other support elements are used in burst-prone conditions to absorb the kinetic energy of the removed rock to avoid sudden and violent failures. This paper develops numerical and a novel analytical simulation technique for cable bolts to assess their structural behaviour under static and dynamic loading conditions. The numerical and analytical models are then validated against experimental observations reported in the literature, which demonstrates the reliability of the proposed models.
基金supported by the Chinese National Natural Science Foundation (Nos. 51627804, 41572249)the State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining & Technology (No. SKLGDUEK1825)
文摘To study the tensile mechanical properties of constant resistance bolts, the RFPA(Rock Failure Process Analysis) statics software is used to perform a uniaxial tensile test on a constant resistance bolt. The numerical test results show that the plastic strain value is 12 times the magnitude of the elastic strain. During plastic deformation, the fluctuation in the stress magnitude is relatively stable, indicating that the bolt has good constant resistance characteristics. The numerical test results are in good agreement with the laboratory test results of M.C. He, and the accuracy and reliability of the numerical test method are verified. Therefore, the RFPA software with coupled static-dynamic loading is further adopted to study the supporting effects of traditional bolts and constant resistance bolts under coupled staticdynamic loading. The numerical comparison of the test results show that the constant resistance bolts can effectively control the deformation amount and rate of the laneway surrounding rock, reduce the total and rate of increase in the accumulated acoustic emissions,decrease the stress on the units in the model and protect the stability of the laneway. This paper verifies that a constant resistance bolt has better impact resistance mechanical properties than those of a traditional bolt and provides an effective way to control rock burst and soft rock that is prone to large deformation damage.
