This paper presents a study on the valorization of local materials such as desert dune sand obtained from Laghouat region in the South Algeria and mine bentonite intended for the realization of liner base layers in th...This paper presents a study on the valorization of local materials such as desert dune sand obtained from Laghouat region in the South Algeria and mine bentonite intended for the realization of liner base layers in the conception of insulation barriers for hazardous waste facilities. In practice, an economical mixture satisfying the hydraulic requirements is generally concerned. First, in order to get an adequate dune sand ebentonite mixture compacted to the optimum Proctor condition, an investigation on saturated hydraulic behavior is carried out in this study for different mixtures. Using oedometer test（indirect measurement）, the adequate mixture of 85% dune sand and 15% bentonite satisfies the conditions of saturated hydraulic conductivity（k 〈 10^（-9）m/s）. This result of the adequate mixture is also confirmed by direct measurement of saturated hydraulic conductivity using triaxial cell. Second, the unsaturated hydraulic conductivity of the adequate mixture is measured with an original vapor equilibrium technique（VET） used for S r〈 30%（very high suction s 〉 3 MPa）. This technique is conducted based on the exploitation of the water retention curve in order to establish the relationships between hydraulic conductivity, degree of saturation, and suction. It shows that the hydraulic conductivity increases with the degree of saturation and decreases with the suction. However, the hydraulic conductivity has a constant value for suctions larger than 20 MPa. The selected dune sandebentonite mixture satisfies the regulation requirements and hence constitutes a good local and economical material for the conception of barrier base liners.展开更多
基金financially supported by the National Program on Key Basic Research Project(Grant No.210CB226800)the National Natural Science Foundation of China(Grant Nos.51274022 and 51174016)
文摘This paper presents a study on the valorization of local materials such as desert dune sand obtained from Laghouat region in the South Algeria and mine bentonite intended for the realization of liner base layers in the conception of insulation barriers for hazardous waste facilities. In practice, an economical mixture satisfying the hydraulic requirements is generally concerned. First, in order to get an adequate dune sand ebentonite mixture compacted to the optimum Proctor condition, an investigation on saturated hydraulic behavior is carried out in this study for different mixtures. Using oedometer test（indirect measurement）, the adequate mixture of 85% dune sand and 15% bentonite satisfies the conditions of saturated hydraulic conductivity（k 〈 10^（-9）m/s）. This result of the adequate mixture is also confirmed by direct measurement of saturated hydraulic conductivity using triaxial cell. Second, the unsaturated hydraulic conductivity of the adequate mixture is measured with an original vapor equilibrium technique（VET） used for S r〈 30%（very high suction s 〉 3 MPa）. This technique is conducted based on the exploitation of the water retention curve in order to establish the relationships between hydraulic conductivity, degree of saturation, and suction. It shows that the hydraulic conductivity increases with the degree of saturation and decreases with the suction. However, the hydraulic conductivity has a constant value for suctions larger than 20 MPa. The selected dune sandebentonite mixture satisfies the regulation requirements and hence constitutes a good local and economical material for the conception of barrier base liners.
