Callovo-Oxfordian （COx） argillite obtained from the excavation of high-level radioactive waste geological disposal has been evaluated as an alternative sealing/backfill material in France. This paper presents an exp...Callovo-Oxfordian （COx） argillite obtained from the excavation of high-level radioactive waste geological disposal has been evaluated as an alternative sealing/backfill material in France. This paper presents an experimental investigation into the hydro-mechanical behaviour of compacted crushed COx argillite. A series of oedorneter compressive tests including various loading-unloading cycles were conducted on COx argillite powders at different initial water contents. After reaching the desired dry density （2.0 Mg/m^3）, the vertical stress was reduced to different levels （7.0 and 0.5 MPa） and the compacted sample was then flooded under constant volume conditions while measuring the changes in the vertical stress. It was found that the initial water content significantly affects the compressive behaviour. The measured saturated hydraulic conductivity is less than 1×10^-10m/s.展开更多
Natural rock joint permeability deviates from the classic fluid flow governing equations due to the inher-ent fracture surface roughness(i.e.,contact points,spatial correlation,matching,varying aperture,iso-lated void...Natural rock joint permeability deviates from the classic fluid flow governing equations due to the inher-ent fracture surface roughness(i.e.,contact points,spatial correlation,matching,varying aperture,iso-lated voids,infilling material,tortuosity and channellings)and engineering disturbance such as excavations.To improve the accuracy of fracture permeability evaluation,many efforts have been made in analytical,experimental,and numerical methods.This study reviews the modified mathematical gov-erning equations of fluid flow and classifies them based on different influencing factors,such as friction factor,aperture,tortuosity,inertia,and various in situ stress effects.Various experimental and simulation techniques for the coupled normal-and shear-stress flow problems were assessed,and their advantages and disadvantages were also analysed.Furthermore,different surface roughness descriptions and their impacts on mechanical and hydraulic behaviours were discussed,followed by the potential research directions for fracture flow problems.展开更多
基金Supported by the French National Radioactive Waste Management Agency
文摘Callovo-Oxfordian （COx） argillite obtained from the excavation of high-level radioactive waste geological disposal has been evaluated as an alternative sealing/backfill material in France. This paper presents an experimental investigation into the hydro-mechanical behaviour of compacted crushed COx argillite. A series of oedorneter compressive tests including various loading-unloading cycles were conducted on COx argillite powders at different initial water contents. After reaching the desired dry density （2.0 Mg/m^3）, the vertical stress was reduced to different levels （7.0 and 0.5 MPa） and the compacted sample was then flooded under constant volume conditions while measuring the changes in the vertical stress. It was found that the initial water content significantly affects the compressive behaviour. The measured saturated hydraulic conductivity is less than 1×10^-10m/s.
文摘Natural rock joint permeability deviates from the classic fluid flow governing equations due to the inher-ent fracture surface roughness(i.e.,contact points,spatial correlation,matching,varying aperture,iso-lated voids,infilling material,tortuosity and channellings)and engineering disturbance such as excavations.To improve the accuracy of fracture permeability evaluation,many efforts have been made in analytical,experimental,and numerical methods.This study reviews the modified mathematical gov-erning equations of fluid flow and classifies them based on different influencing factors,such as friction factor,aperture,tortuosity,inertia,and various in situ stress effects.Various experimental and simulation techniques for the coupled normal-and shear-stress flow problems were assessed,and their advantages and disadvantages were also analysed.Furthermore,different surface roughness descriptions and their impacts on mechanical and hydraulic behaviours were discussed,followed by the potential research directions for fracture flow problems.
