The Large Interface Direct Shear Apparatus And Its Application

The problem of contact surface between soil and structure is widely existed in engineering problems such as civil,water Conservancy,etc.As more and more high earth dams are established,For example,the Zipingpu panel dam(height is 158m),Jiang Pinghe panel dam(height is 219m),Monkey Rock panel dam(height is 223m),etc.The contact surface problem between coarse grained soil and seepage control structure has become an important research direction in geotechnical engineering.At present,the test of contact surface between coarse grained soils and structure surfaces is based on the direct shear tester.Although the traditional direct shear test has the advantages of simple structure,simple test process,easy operation,etc.But the contact panels are generally placed under the soil particles,the normal force is transmitted to the contact panel through the upper side of the Earth body.Because of the unevenness of soil particles,the force passed to the contact panel is uneven.On the other hand,the traditional direct shear test apparatus has a smaller size and can only be done with small granular sand test and cannot study the test characteristics of the contact surfaces of coarse grained soils and structures.Based on the above situation,referring to the contact surface test apparatus developed at home and abroad,the JAW-500-type large direct shear test apparatus of the Anti-seismic Institute of Dalian University of Technology is reformed,so that the direct shear test apparatus can be carried out under different boundary conditions,monotonous and cyclic contact surface test.Finally,the paper adopts a dam construction material,using smooth plank and steel plate as contact panel,and carries out the experimental research on the contact surface of different structure panels and coarse grained soils.Under the support of the national science fund project(51508071),the following work is done:(1)Through the test of large direct shear test apparatus,the defects in contacting surface test were summarized by using the test apparatus.And combining with the demand of contact surface test,the shear box is reformed and upgraded,the instrument is better solved the problems such as the non-uniformity of the normal stress,the contact area method to the shear swell measurement and the visual test of contact deformation.(2)The contact surface test under different boundary conditions is carried out,the feasibility of the test apparatus is verified,the contact panel is smooth plank and steel plate,the shear type is monotonous and cyclic shearing,and the test results of the contact panel are the plank and the plate respectively.