By analyzing GPS, leveling and gravity observation data from the Minle, Huazangsi and Shagouhe profiles across the Qilian Mountain-Haiyuan fault during 2005 - 2009, the changes of these data and activity characteristi...By analyzing GPS, leveling and gravity observation data from the Minle, Huazangsi and Shagouhe profiles across the Qilian Mountain-Haiyuan fault during 2005 - 2009, the changes of these data and activity characteristics of the main faults in different time are obtained. The results show that the Changma-Erbo, Maomaoshan, Zhunglanghe and Haiyuan faults have been active in recent years. The relationship between the vertical displacement and mobile gravity data is analyzed, and the results reveal the gravity changes are mainly due to mass transfer. The results of GPS observation show that the direction of the horizontal movement velocity was almost along the fault strike in 2006 - 2007, while the horizontal velocity deviated from the fault direction in 2007 - 2008, characterized by increased eastward displacement. Further analysis upon removal of the linear trend on the time series of the N and E coordinate values of the continuous observation stations of the Crustal Movement Observation Network of China near the three profiles reveals that the Wenchuan earthquake had an effect on the observations in 2007 - 2008. Comparing the gravitational changes in 2008 - 2009 with the Bouguer gravity anomaly background, we find that the area near Minle profile is in the stage of adjustment and recovery, while the anomaly is not completely recovered around Huazangsi and Shagouhe profiles.展开更多
The distinct characteristic of subcritical propagation requires at least two control parameters to completely express expansion of cracks in the concrete.The basic definition of crack tip opening displacement(CTOD)is ...The distinct characteristic of subcritical propagation requires at least two control parameters to completely express expansion of cracks in the concrete.The basic definition of crack tip opening displacement(CTOD)is corrected based on the monitored variable of crack mouth opening displacement(CMOD).The improved CTOD criterion,called the double CTODd criterion,for the abnormality diagnosis of cracks in the concrete is constructed based on the fictitious crack model and linear asymptotic superposition assumptions of the concrete.The double CTODd criterion is verified using two specimens of three-point bending notched beam.The verification results are reasonable and correct.The establishment of the double CTODd criterion lays a solid theoretical foundation for the abnormality diagnosis of cracks in concrete structures(such as concrete dams)based on CMOD.展开更多
基金sponsored by Special Scientific Research Project,China Earthquake Administration(200908029)National Natural Science Foundation of China(40674057)
文摘By analyzing GPS, leveling and gravity observation data from the Minle, Huazangsi and Shagouhe profiles across the Qilian Mountain-Haiyuan fault during 2005 - 2009, the changes of these data and activity characteristics of the main faults in different time are obtained. The results show that the Changma-Erbo, Maomaoshan, Zhunglanghe and Haiyuan faults have been active in recent years. The relationship between the vertical displacement and mobile gravity data is analyzed, and the results reveal the gravity changes are mainly due to mass transfer. The results of GPS observation show that the direction of the horizontal movement velocity was almost along the fault strike in 2006 - 2007, while the horizontal velocity deviated from the fault direction in 2007 - 2008, characterized by increased eastward displacement. Further analysis upon removal of the linear trend on the time series of the N and E coordinate values of the continuous observation stations of the Crustal Movement Observation Network of China near the three profiles reveals that the Wenchuan earthquake had an effect on the observations in 2007 - 2008. Comparing the gravitational changes in 2008 - 2009 with the Bouguer gravity anomaly background, we find that the area near Minle profile is in the stage of adjustment and recovery, while the anomaly is not completely recovered around Huazangsi and Shagouhe profiles.
基金supported by the Open Foundation of State Key Laboratory of Hydrology-Water Resources (Grant No. 2012490211)the Doctoral Scientific Research Fund of Northwest A&F University in 2012 (Grant No.2012BSJJ007)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. QN2013046)the National Natural Science Foundation of China (Grant No. 51139001)
文摘The distinct characteristic of subcritical propagation requires at least two control parameters to completely express expansion of cracks in the concrete.The basic definition of crack tip opening displacement(CTOD)is corrected based on the monitored variable of crack mouth opening displacement(CMOD).The improved CTOD criterion,called the double CTODd criterion,for the abnormality diagnosis of cracks in the concrete is constructed based on the fictitious crack model and linear asymptotic superposition assumptions of the concrete.The double CTODd criterion is verified using two specimens of three-point bending notched beam.The verification results are reasonable and correct.The establishment of the double CTODd criterion lays a solid theoretical foundation for the abnormality diagnosis of cracks in concrete structures(such as concrete dams)based on CMOD.
