This paper presents the results of the shear strength（frictional strength） of cemented paste backfillcemented paste backfill（CPB-CPB） and cemented paste backfillerock wall（CPB-rock） interfaces. The frictional be...This paper presents the results of the shear strength（frictional strength） of cemented paste backfillcemented paste backfill（CPB-CPB） and cemented paste backfillerock wall（CPB-rock） interfaces. The frictional behaviors of these interfaces were assessed for the short-term curing times（3 d and 7 d） using a direct shear apparatus RDS-200 from GCTS（Geotechnical Consulting ＆ Testing Systems）. The shear（friction） tests were performed at three different constant normal stress levels on flat and smooth interfaces. These tests aimed at understanding the mobilized shear strength at the CPB-rock and CPB-CPB interfaces during and/or after open stope filling（no exposed face）. The applied normal stress levels were varied in a range corresponding to the usually measured in-situ horizontal pressures（longitudinal or transverse） developed within paste-filled stopes（uniaxial compressive strength, s c 150 k Pa）. Results show that the mobilized shear strength is higher at the CPB-CPB interface than that at the CPB-rock interface. Also, the perfect elastoplastic behaviors observed for the CPB-rock interfaces were not observed for the CPB-CPB interfaces with low cement content which exhibits a strain-hardening behavior. These results are useful to estimate or validate numerical model for pressures determination in cemented backfill stope at short term. The tests were performed on real backfill and granite. The results may help understanding the mechanical behavior of the cemented paste backfill in general and, in particular, analyzing the shear strength at backfillebackfill and backfill-rock interfaces.展开更多
The dynamic processes and characteristics of solid phase diffusion-bonding of interfacial atoms at high tempera-tures and the effect of that on bonding strength of Ni(111)/)/-Al_(2)O_(3)(0001)interface were investigat...The dynamic processes and characteristics of solid phase diffusion-bonding of interfacial atoms at high tempera-tures and the effect of that on bonding strength of Ni(111)/)/-Al_(2)O_(3)(0001)interface were investigated through molecular dynamics.It is shown that atomic diffusion occurs at the Ni/Al_(2)O_(3) interface in the temperature range from 698 K to 1,098 K,and proceeds mainly from the Ni side to the ) Al_(2)O_(3) side.The interface was previously reconstructed by solid bonding below the melting temperature,leading to the amorphization of the interface.Be-sides,the intermetallic complexes such as Al_(m)Ni_(n)(e.g.,AlNi_(3)),metal oxide NiO and Ni-Al-O bonds were formed gradually during the diffusion process of atoms.The formation mechanisms of the Ni-Al,Ni-O,and Ni-Al-O bonds are revealed.Based on the reconstructed structure,the adhesion effort at the interface is compared.The higher the temperature,the larger the bond number and the higher the interfacial bonding strength.展开更多
文摘This paper presents the results of the shear strength（frictional strength） of cemented paste backfillcemented paste backfill（CPB-CPB） and cemented paste backfillerock wall（CPB-rock） interfaces. The frictional behaviors of these interfaces were assessed for the short-term curing times（3 d and 7 d） using a direct shear apparatus RDS-200 from GCTS（Geotechnical Consulting ＆ Testing Systems）. The shear（friction） tests were performed at three different constant normal stress levels on flat and smooth interfaces. These tests aimed at understanding the mobilized shear strength at the CPB-rock and CPB-CPB interfaces during and/or after open stope filling（no exposed face）. The applied normal stress levels were varied in a range corresponding to the usually measured in-situ horizontal pressures（longitudinal or transverse） developed within paste-filled stopes（uniaxial compressive strength, s c 150 k Pa）. Results show that the mobilized shear strength is higher at the CPB-CPB interface than that at the CPB-rock interface. Also, the perfect elastoplastic behaviors observed for the CPB-rock interfaces were not observed for the CPB-CPB interfaces with low cement content which exhibits a strain-hardening behavior. These results are useful to estimate or validate numerical model for pressures determination in cemented backfill stope at short term. The tests were performed on real backfill and granite. The results may help understanding the mechanical behavior of the cemented paste backfill in general and, in particular, analyzing the shear strength at backfillebackfill and backfill-rock interfaces.
基金supported by the National Natural Science Founda-tion of China(Grant Nos.:52076033 and 51836001).
文摘The dynamic processes and characteristics of solid phase diffusion-bonding of interfacial atoms at high tempera-tures and the effect of that on bonding strength of Ni(111)/)/-Al_(2)O_(3)(0001)interface were investigated through molecular dynamics.It is shown that atomic diffusion occurs at the Ni/Al_(2)O_(3) interface in the temperature range from 698 K to 1,098 K,and proceeds mainly from the Ni side to the ) Al_(2)O_(3) side.The interface was previously reconstructed by solid bonding below the melting temperature,leading to the amorphization of the interface.Be-sides,the intermetallic complexes such as Al_(m)Ni_(n)(e.g.,AlNi_(3)),metal oxide NiO and Ni-Al-O bonds were formed gradually during the diffusion process of atoms.The formation mechanisms of the Ni-Al,Ni-O,and Ni-Al-O bonds are revealed.Based on the reconstructed structure,the adhesion effort at the interface is compared.The higher the temperature,the larger the bond number and the higher the interfacial bonding strength.
