This paper presents the results of triaxial tests conducted for the investigation of the influence of geotextiles on stress-strain and volumetric change behaviour of reinforced sandy soil. Tests were carried out on lo...This paper presents the results of triaxial tests conducted for the investigation of the influence of geotextiles on stress-strain and volumetric change behaviour of reinforced sandy soil. Tests were carried out on loose sandy soil. The experimental program includes drained compression tests on samples reinforced with different values of both geotextiles layers （Ng） and confining pressure （σ′c）. Two methods of preparation were used： air pluviation （AP） and moist tamping （MT）. Test results show that the geotextiles induce a quasi-linear increase in the stress deviator （q） and volume contraction in the reinforced sand. Method of preparation significantly affects the shear strength; samples prepared by the air pluviation method and mobilized deviator stresses are significantly higher than those prepared by moist tamping method. Geotextiles restrict the dilation of reinforced sandy soil and consequently the contraction increases. The mobilized friction angle increases with increasing number of layers and decreases with increasing initial confining pressure. Samples prepared by moist tamping present mobilized friction angles significantly lower than those prepared by air pluviation method. For samples prepared by the air pluviation method, the secant modulus at ε1=1% and 5% decreases with increasing geotextile layers; those prepared by the moist tamping method, secant modulus at ε1=1% and 5% increases with increasing number of geotextile layer sand confining pressure. From 10% axial strain, secant modulus increases with increasing inclusions of geotextile layers.展开更多
The equivalent permeability tensor is essential to the application of the equivalent porous media model in the numerical seepage simulation for fractured rock masses. In this paper, a revised solution of the equivalen...The equivalent permeability tensor is essential to the application of the equivalent porous media model in the numerical seepage simulation for fractured rock masses. In this paper, a revised solution of the equivalent permeability tensor is proposed to represent the influence of the fracture connectivity in discontinuous fractures. A correction coefficient is involved to reflect the com- plex seepage flow type through the rock bridge. This correction coefficient is back analyzed from single-hole packer tests, based on the Artificial Neural Network （ANN） back analysis and the Finite Element Method （FEM） seepage simulation. The limitation of this back analysis algorithm is that the number of single-hole packer tests should be equal or greater than the number of fracture sets, and three is the maximum number of the fracture sets. The proposed solution and the back analysis algorithm are applied in the permea- bility measurement and the seepage simulation for the Xiaowan arch dam foundation.展开更多
文摘This paper presents the results of triaxial tests conducted for the investigation of the influence of geotextiles on stress-strain and volumetric change behaviour of reinforced sandy soil. Tests were carried out on loose sandy soil. The experimental program includes drained compression tests on samples reinforced with different values of both geotextiles layers （Ng） and confining pressure （σ′c）. Two methods of preparation were used： air pluviation （AP） and moist tamping （MT）. Test results show that the geotextiles induce a quasi-linear increase in the stress deviator （q） and volume contraction in the reinforced sand. Method of preparation significantly affects the shear strength; samples prepared by the air pluviation method and mobilized deviator stresses are significantly higher than those prepared by moist tamping method. Geotextiles restrict the dilation of reinforced sandy soil and consequently the contraction increases. The mobilized friction angle increases with increasing number of layers and decreases with increasing initial confining pressure. Samples prepared by moist tamping present mobilized friction angles significantly lower than those prepared by air pluviation method. For samples prepared by the air pluviation method, the secant modulus at ε1=1% and 5% decreases with increasing geotextile layers; those prepared by the moist tamping method, secant modulus at ε1=1% and 5% increases with increasing number of geotextile layer sand confining pressure. From 10% axial strain, secant modulus increases with increasing inclusions of geotextile layers.
基金supported by the National Natural Science Foundation of China(Grant No.51079109)
文摘The equivalent permeability tensor is essential to the application of the equivalent porous media model in the numerical seepage simulation for fractured rock masses. In this paper, a revised solution of the equivalent permeability tensor is proposed to represent the influence of the fracture connectivity in discontinuous fractures. A correction coefficient is involved to reflect the com- plex seepage flow type through the rock bridge. This correction coefficient is back analyzed from single-hole packer tests, based on the Artificial Neural Network （ANN） back analysis and the Finite Element Method （FEM） seepage simulation. The limitation of this back analysis algorithm is that the number of single-hole packer tests should be equal or greater than the number of fracture sets, and three is the maximum number of the fracture sets. The proposed solution and the back analysis algorithm are applied in the permea- bility measurement and the seepage simulation for the Xiaowan arch dam foundation.
