The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mech...The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mechanical properties of rock.However,the used incremental cyclic loading−unloading compression test for the determination of strength components is very complicated,which limits the application of CWFS model.In this paper,incremental cyclic loading−unloading compression test was firstly carried out to study the evolution of deformation and the strength properties of Beishan granite after various temperatures treated under different confining pressures.We found the axial and lateral unloading modulus are closely related to the applied stress and damage state of rock.Based on these findings,we can accurately determine the plastic strain during the entire failure process using conventional tri-axial compression test data.Furthermore,a strength component(cohesive and frictional strength)determination method was developed using conventional triaxial compression test.Using this method,we analyzed the variation of strength mobilization and deformation properties of Beishan granite after various temperatures treated.At last,a non-simultaneous strength mobilization model for thermally treated granite was obtained and verified by numerical simulation,which demonstrated the effectiveness of the proposed strength determination method.展开更多
The microstmcture evolution of plastic-bonded explosives (PBXs) after thermal stimulus plays a key role in PBX performance. In this paper, the nanoscale pores of thermal-treated octahydro-1,3,5,7-tetranitro-1,3,5,7 ...The microstmcture evolution of plastic-bonded explosives (PBXs) after thermal stimulus plays a key role in PBX performance. In this paper, the nanoscale pores of thermal-treated octahydro-1,3,5,7-tetranitro-1,3,5,7 tetrazocine (HMX)- based PBXs with different HMX particle sizes [approximately 40 (FLIP) and 100 μm (LHP)] were measured using small- angle X-ray scattering (SAXS). No obvious pore variations were found in the LHP samples heated at 160 ℃ for 6 h, whereas the amount of pores of FHP decreased when subjected to 160 ℃ for 6 h. At 180 ℃, the average pore radii of FHP and LHP decreased from approximately 45 nm to 25 nm, and the total pore volume increased distinctively because of phase transformation. The LHP sample reached a high level of pore content after being held at 180 ℃ for 1 h, whereas FHP required 3 h. Both FHP and LHP had relatively high pore volumes when subjected to 200 ℃ for 1 and 3 h.展开更多
基金Project(41902301)supported by the National Natural Science Foundation of ChinaProject(20201Y185)supported by the Science and Technology Foundation of Guizhou Province,China+2 种基金Project(Z018023)supported by the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,IRSM,CASProject(201822)supported by the Foundation for Young Talents of Guizhou University,ChinaProject(2017-5402)supported by the Mountain Geohazard Prevention R&D Center of Guizhou Province,China。
文摘The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mechanical properties of rock.However,the used incremental cyclic loading−unloading compression test for the determination of strength components is very complicated,which limits the application of CWFS model.In this paper,incremental cyclic loading−unloading compression test was firstly carried out to study the evolution of deformation and the strength properties of Beishan granite after various temperatures treated under different confining pressures.We found the axial and lateral unloading modulus are closely related to the applied stress and damage state of rock.Based on these findings,we can accurately determine the plastic strain during the entire failure process using conventional tri-axial compression test data.Furthermore,a strength component(cohesive and frictional strength)determination method was developed using conventional triaxial compression test.Using this method,we analyzed the variation of strength mobilization and deformation properties of Beishan granite after various temperatures treated.At last,a non-simultaneous strength mobilization model for thermally treated granite was obtained and verified by numerical simulation,which demonstrated the effectiveness of the proposed strength determination method.
基金supported by the National Natural Science Foundation of China(Grant Nos.11205137,11079043,and 11302199)
文摘The microstmcture evolution of plastic-bonded explosives (PBXs) after thermal stimulus plays a key role in PBX performance. In this paper, the nanoscale pores of thermal-treated octahydro-1,3,5,7-tetranitro-1,3,5,7 tetrazocine (HMX)- based PBXs with different HMX particle sizes [approximately 40 (FLIP) and 100 μm (LHP)] were measured using small- angle X-ray scattering (SAXS). No obvious pore variations were found in the LHP samples heated at 160 ℃ for 6 h, whereas the amount of pores of FHP decreased when subjected to 160 ℃ for 6 h. At 180 ℃, the average pore radii of FHP and LHP decreased from approximately 45 nm to 25 nm, and the total pore volume increased distinctively because of phase transformation. The LHP sample reached a high level of pore content after being held at 180 ℃ for 1 h, whereas FHP required 3 h. Both FHP and LHP had relatively high pore volumes when subjected to 200 ℃ for 1 and 3 h.