Width design for gobs and isolated coal pillars based on overall burst-instability prevention in coal mines  

作　　者：Junfei Zhang Fuxing Jiang Sitao Zhu Lei Zhang 

机构地区：[1]School of Civil and Environmental Engineering, University of Science and Technology Beijing

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2016年第4期551-558,共8页岩石力学与岩土工程学报（英文版）

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)

摘　　要：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.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.

关 键 词：Dune sand Bentonite Valorization Landfill liners Hydraulic conductivity 

分 类 号：TD822.3[矿业工程—煤矿开采]