Abstract:A new laboratory apparatus for coupling shear and seepage of rock joints is developed and used to investigate coupling effect of joint shear deformation and dilatancy on hydraulic conductivity of rock joints. The test apparatus consists of three parts:a normal and shear force loading system,a hydraulic loading system and a sealing shear box,each including a control and data acquisition unit. The maximum normal pressure and shear pressure are both 600 kN. The sizes of specimens for directional flow are 200 mm in length along permeation direction,100 mm in width perpendicular to the permeation direction and 100 mm in height,while those for radial flow are 300 mm in length,300 mm in width and 150 mm in height. During the shear test of joint specimen,at least until the water pressure reaches 0.5 MPa,equaling to the hydrostatic pressure caused by a water head of 50 m,leakage will not happen at the shear box. Besides the loading condition of constant normal load and constant normal volume,shear test can also be adopted with constant normal stiffness,which is considered to reproduce more real-world phenomena than other testing methods by equating spring stiffness with the stiffness of surrounding ground. The principle of hydraulic loading system is similar to a “needle syringe”. In the course of coupling shear and seepage test,the flow rate and water pressure of water inlet and outlet can be measured at any time. The sealing shear box is designed especially to meet the purpose that seepage water of high-pressure flows along appointed path of joint face during the test while no leakage will happen. A lot of shear-seepage tests are carried out on rock samples from Jinping area on Yalong River of China. The results reveal the following facts:(1) the apparatus can satisfy the requirement for coupled shear-seepage test of rock joints;(2) the apparatus is easy to operate with satisfactory performance,and the precision of results meet the national standards for regular test. It can be used to investigate certain scientific natures of reservoir and dam safety,cavern excavation,deep mining process,deep petroleum extraction,nuclear waste disposal and geothermal excavation,etc..