By the methods of uniaxial single-stage loading and graded incremental cyclic loading, the creep experiments were performed on the deep saturated rock from Dongguashan Mine, and the creep curves of saturated rock unde...By the methods of uniaxial single-stage loading and graded incremental cyclic loading, the creep experiments were performed on the deep saturated rock from Dongguashan Mine, and the creep curves of saturated rock under different loading stresses were obtained. By comparing with the creep rule of dry rock in the same location, the creep rule of deep saturated rock was analyzed. Based on the united rheological mechanical model, the rheological model of deep saturated rock was recognized, and the parameters of the model were determined. The results show that the creep curves are very smooth under low stress, but the phenomena of wave and catastrophe turn up under high stress, and the bearing capacity of rock is weakening over time. The rheological properties of saturated and dry rocks are very different under tlie condition of deep high stress, especially when unloading, degradation and damage of rock quality is more serious, and the effect of water cannot be neglected. The H--HIN--NJS model （Schofield-Scott-Blair model） was selected to represent the rheology rule of deep saturated rock, and the fitting curves of model agree well with the experiment data, so the selected model is reasonable.展开更多
A regional model of vegetation dynamics was revised to include land use as a constraint to vegetation dynamics and primary production processes. The model was applied to a forest transect in eastern China (NSTEC, Nort...A regional model of vegetation dynamics was revised to include land use as a constraint to vegetation dynamics and primary production processes. The model was applied to a forest transect in eastern China (NSTEC, North-South transect of eastern China) to investigate the responses of the transect to possible future climatic change. The simulation result indicated that land use has profound effects on vegetation transition and primary production. In particular, land use reduced competition among vegetation classes and tended to result in less evergreen broadleaf forests but more shrubs and grasses in the transect area. The simulation runs with land use constraint also gave much more realistic estimation about net primary productivity as well as responses of the productivity to future climatic change along the transect. The simulations for future climate scenarios projected by general circulation models (GCM) with doubled atmospheric CO2 concentration predicted that deciduous broadleaf forests would increase, but conifer forests, shrubs and grasses would decrease. The overall effects of doubling CO2 and climatic changes on NSTEC were to produce an increased net primary productivity (NPP) at equilibrium for all seven GCM scenarios. The predicted range of NPP variation in the north is much larger than that in the south.展开更多
基金Project (50774095) supported by the National Natural Science Foundation of ChinaProject (200449) supported by China National Outstanding Doctoral Dissertations Special Funds
文摘By the methods of uniaxial single-stage loading and graded incremental cyclic loading, the creep experiments were performed on the deep saturated rock from Dongguashan Mine, and the creep curves of saturated rock under different loading stresses were obtained. By comparing with the creep rule of dry rock in the same location, the creep rule of deep saturated rock was analyzed. Based on the united rheological mechanical model, the rheological model of deep saturated rock was recognized, and the parameters of the model were determined. The results show that the creep curves are very smooth under low stress, but the phenomena of wave and catastrophe turn up under high stress, and the bearing capacity of rock is weakening over time. The rheological properties of saturated and dry rocks are very different under tlie condition of deep high stress, especially when unloading, degradation and damage of rock quality is more serious, and the effect of water cannot be neglected. The H--HIN--NJS model （Schofield-Scott-Blair model） was selected to represent the rheology rule of deep saturated rock, and the fitting curves of model agree well with the experiment data, so the selected model is reasonable.
文摘A regional model of vegetation dynamics was revised to include land use as a constraint to vegetation dynamics and primary production processes. The model was applied to a forest transect in eastern China (NSTEC, North-South transect of eastern China) to investigate the responses of the transect to possible future climatic change. The simulation result indicated that land use has profound effects on vegetation transition and primary production. In particular, land use reduced competition among vegetation classes and tended to result in less evergreen broadleaf forests but more shrubs and grasses in the transect area. The simulation runs with land use constraint also gave much more realistic estimation about net primary productivity as well as responses of the productivity to future climatic change along the transect. The simulations for future climate scenarios projected by general circulation models (GCM) with doubled atmospheric CO2 concentration predicted that deciduous broadleaf forests would increase, but conifer forests, shrubs and grasses would decrease. The overall effects of doubling CO2 and climatic changes on NSTEC were to produce an increased net primary productivity (NPP) at equilibrium for all seven GCM scenarios. The predicted range of NPP variation in the north is much larger than that in the south.
