MethodforDirectShearTestonaRockJoint.docVIP

Method for Direct Shear Test on a Rock Joint 1 Scope This standard test method covers the determination of the engineering (strength) properties for a rock joint as the slope, foundation, tunnel and underground cavity. Especially, this test method is conducted by the direct shear test using shear box, it differs from the designation JGS 3511-2004 ‘Method for In-situ Direct Shear Test on Rocks’. 2 Normative Reference The following referenced articles are indispensable for the application of this method. The newest version of the following designation shall apply to this test method. JGS 3821-2006 Method for investigation on geometrical information of discontinuity distribution in rock mass 3 Definitions This standard uses the terms defined as follows. a) Discontinuity: A weak plane in the form of joint, bedding, etc., which disturbs the mechanical continuity of rock material, and whose tensile strength is either nil or negligible. b) Roughness: Geometrical roughness on the surface of a discontinuity. c) Infilling: A material which is used to fill a gap created by a discontinuity. d) Maximum shear strength: Maximum value of shear stress. e) Residual shear strength: Constant value of shear stress after showing maximum shear strength. f) Sample: Rock material of boring core and sampling of blocked shape. It contained a rock joint as a shear plane. g) Specimen: Modified sample as setting in a shear box. h) Angle of shear resistance: Inclination of Coulomb’s failure line on the relationship between normal stress and shear stress. i) Cohesion of rock joint: Y-Intercept of Coulomb’s failure line on the relationship between normal stress and shear stress. 4 Test Apparatus Test apparatus is as follows. 4.1 Shear Box Shear box is divided a moving box and fixed box on boundary of shear plane. Its two parts doesn’t contact each other. Moving box moves parallel to the fixed box. It has enough stiffness under the applied load. 4.2 Apparatus for Loading Apparatus for loadi