Experimental Study on Anisotropic Characteristics of Mica Quartz Schist in Pumped Storage Power Stations
The anisotropic characteristics of mica quartz schist have significant impact on the stability of the surrounding rock of the underground cavern of the pumped storage power station.Through rock and mineral identification,indoor compression test,direct shear test,point load field test and other means,the variation law of strength and deformation of mica quartz schist is analyzed,and the anisotropic characteristics of mica quartz schist with different weathering degrees in different loading directions are studied.The results show that during the long geological history,the minerals of mica quartz schist have formed a strong directional arrangement structure after various geological actions,which makes mica quartz schist have obvious lamellae,resulting in obvious anisotropy in mechanical properties.Under the action of loads in different directions,the com-pressive strength,deformation modulus and elastic modulus of mica quartz schist all show certain anisotropy.With the increase of the angle be-tween the horizontal and the schistosity plane,the uniaxial compressive strength,deformation modulus and elastic modulus of mica quartz schist first decrease and then increase,showing a"U"-shaped variation law.When the angle between the horizontal and the schistosity plane a is 0°,the rock failure is compression shear failure,and when α is 40°,the rock failure is compression shear failure.When α is 70°,the rock failure is compound shear failure,and when α is 90°,the rock failure is splitting tensile failure.The direct shear test indicates that the bonding strength be-tween schistosity planes is low,and dislocation is prone to occur when the load direction is parallel to the schistosity direction,reflecting the ani-sotropy of mica quartz schist.Through the point load test,the point load strength of mica quartz schist with different weathering degrees and differ-ent loading directions shows obvious anisotropy.The strength of parallel schistosity planes is mainly provided by the bonding strength between schistosity layers,rather than the mechanical strength characteristics of mica quartz schist itself.Meanwhile,the anisotropy of mica quartz schist is slightly weakened as the weathering degree decreases.
mica quartz schistpumped storage power stationanisotropyindoor rock testpoint load test
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