Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it.Displacement distribution patterns of r...Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it.Displacement distribution patterns of rock masses in active fault zones which have been investigated previously are the key design basis for such projects.Therefore,a discrete element numerical model with different fault types,slip time,dip angles,and complex geological features was established,and then the creep slip for normal,reverse,and strike-slip faults were simulated to analyze the displacement distribution in the fault rock mass.A disk rotation test system and the corresponding laboratory test method were developed for simulating rock mass displacement induced by creep slippage of faults.A series of rotation tests for softand hard-layered specimens under combined compression and torsional stress were conducted to verify the numerical results and analyze the factors influencing the displacement distribution.An S-shaped displacement distribution independent of fault dip angle was identified corresponding to reverse,normal,and strike-slip faults.The results indicated that the higher the degree of horizontal extrusion,the softer the rock mass at the fault core,and the higher the degree of displacement concentration in the fault core;about 70%of the creep slip displacement occurs within this zone under 100 years of creep slippage.展开更多
Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip su...Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.展开更多
Citrus tristeza virus （CTV）, the most devastating viral pathogen in citrus, causes tremendous economic losses to citrus industry worldwide. The CTV isolates exhibit variable pathogenicities on their hosts indicating...Citrus tristeza virus （CTV）, the most devastating viral pathogen in citrus, causes tremendous economic losses to citrus industry worldwide. The CTV isolates exhibit variable pathogenicities on their hosts indicating a mixed population of the CTV in nature. Several fragments within the CTV genome have been used for studying the genetic diversity of the CTV, however, the best region for rapid the CTV strain differentiation is still absent at present. In present study, a systemic analysis was carried out to evaluate the best region within the CTV genome for rapid CTV strain differentiation. Results of our study showed that the major coat protein （CP） coding region was the best region for this purpose. Using pair-wise distance frequency distribution plot, a reasonable genetic distance cut-off value was set for the CTV CP gene for the CTV strain differentiation. Using this criterion, eight CTV strains, including seven well characterized and a new strain, were successfully differentiated using 537 CTV isolates reported from 38 countries. The global strain distribution pattern was then determined and discussed. Our results also provided a new insight into the evolution and spreading of the virus, as well as the information for developing proper disease management strategy.展开更多
基金Project(U1865203)supported by the Key Projects of the Yalong River Joint Fund of the National Natural Science Foundation of ChinaProjects(41941018,51879135)supported by the National Natural Science Foundation of China。
文摘Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it.Displacement distribution patterns of rock masses in active fault zones which have been investigated previously are the key design basis for such projects.Therefore,a discrete element numerical model with different fault types,slip time,dip angles,and complex geological features was established,and then the creep slip for normal,reverse,and strike-slip faults were simulated to analyze the displacement distribution in the fault rock mass.A disk rotation test system and the corresponding laboratory test method were developed for simulating rock mass displacement induced by creep slippage of faults.A series of rotation tests for softand hard-layered specimens under combined compression and torsional stress were conducted to verify the numerical results and analyze the factors influencing the displacement distribution.An S-shaped displacement distribution independent of fault dip angle was identified corresponding to reverse,normal,and strike-slip faults.The results indicated that the higher the degree of horizontal extrusion,the softer the rock mass at the fault core,and the higher the degree of displacement concentration in the fault core;about 70%of the creep slip displacement occurs within this zone under 100 years of creep slippage.
基金Project(2015M580702)supported by the China Postdoctoral Science FoundationProject(51608541)supported by the National Natural Science Foundation of ChinaProject(2014122006)supported by the Guizhou Provincial Department of Transportation Foundation,China
文摘Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.
基金Supported by the National Natural Science Foundation of China (31101417 31101415)+1 种基金Zhejiang Provincial Natural Science Foundation of China (Y3110175 Y3110277)
文摘Citrus tristeza virus （CTV）, the most devastating viral pathogen in citrus, causes tremendous economic losses to citrus industry worldwide. The CTV isolates exhibit variable pathogenicities on their hosts indicating a mixed population of the CTV in nature. Several fragments within the CTV genome have been used for studying the genetic diversity of the CTV, however, the best region for rapid the CTV strain differentiation is still absent at present. In present study, a systemic analysis was carried out to evaluate the best region within the CTV genome for rapid CTV strain differentiation. Results of our study showed that the major coat protein （CP） coding region was the best region for this purpose. Using pair-wise distance frequency distribution plot, a reasonable genetic distance cut-off value was set for the CTV CP gene for the CTV strain differentiation. Using this criterion, eight CTV strains, including seven well characterized and a new strain, were successfully differentiated using 537 CTV isolates reported from 38 countries. The global strain distribution pattern was then determined and discussed. Our results also provided a new insight into the evolution and spreading of the virus, as well as the information for developing proper disease management strategy.
