Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope duri...Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope during excavation of a deep tunnel. Zonal disintegration phenomenon was successfully demonstrated in the laboratory with 3D tests on analogous gypsum models, two circular cracked zones were observed in the test. The linear Mohr-Coulomb yield criterion was used with a constitutive model that showed linear softening and ideal residual plastic to analyze the elasto-plastic field of the enclosing rock mass around a deep tunnel. The results show that tunneling causes a maximum stress zone to appear between an elastic and plastic zone in the surrounding rock. The zonal disintegration phenomenon is analyzed by considering the stress-strain state of the rock mass in the vicinity of the maximum stress zone. Creep instability failure of the rock due to the development of the plastic zone, and transfer of the maximum stress zone into the rock mass, are the cause of zonal disintegration. An analytical criterion for the critical depth at which zonal disintegration can occur is derived. This depth depends mainly on the character and stress concentration coefficient of the rock mass.展开更多
[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated using ultrafiltration membranes at molecular weight of 6 000 Da in order to ...[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated using ultrafiltration membranes at molecular weight of 6 000 Da in order to study on concentration effect of maltose and restoration effect of membranes property through backflushing.[Result] When 40% maltose was concentrated with the membrane,membrane flux weakened rapidly and pores blocked.In contrast,when 15% maltose was concentrated with the same membrane,the membrane flux was high and weakened very slowly.Dextrose equivalent(DE) and luminousness changed from 43% and 91%T before filtration to 50% and 98%T after filtration,respectively.[Conclusion] The research provides a practical method to improve transparency of maltose products and extend quality guarantee period.展开更多
基金Projects 50490275 and 50525825 supported by the National Natural Science Foundation of China
文摘Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope during excavation of a deep tunnel. Zonal disintegration phenomenon was successfully demonstrated in the laboratory with 3D tests on analogous gypsum models, two circular cracked zones were observed in the test. The linear Mohr-Coulomb yield criterion was used with a constitutive model that showed linear softening and ideal residual plastic to analyze the elasto-plastic field of the enclosing rock mass around a deep tunnel. The results show that tunneling causes a maximum stress zone to appear between an elastic and plastic zone in the surrounding rock. The zonal disintegration phenomenon is analyzed by considering the stress-strain state of the rock mass in the vicinity of the maximum stress zone. Creep instability failure of the rock due to the development of the plastic zone, and transfer of the maximum stress zone into the rock mass, are the cause of zonal disintegration. An analytical criterion for the critical depth at which zonal disintegration can occur is derived. This depth depends mainly on the character and stress concentration coefficient of the rock mass.
基金Supported by Demonstration Project of Ecology Restoration on PollutedWater Area in Estuary(2010BAC68B02)
文摘[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated using ultrafiltration membranes at molecular weight of 6 000 Da in order to study on concentration effect of maltose and restoration effect of membranes property through backflushing.[Result] When 40% maltose was concentrated with the membrane,membrane flux weakened rapidly and pores blocked.In contrast,when 15% maltose was concentrated with the same membrane,the membrane flux was high and weakened very slowly.Dextrose equivalent(DE) and luminousness changed from 43% and 91%T before filtration to 50% and 98%T after filtration,respectively.[Conclusion] The research provides a practical method to improve transparency of maltose products and extend quality guarantee period.
