Abstract:Multifunctional apparatus for geotechnical engineering model tests consists of the main engine and accessory devices. The apparatus possesses six functions,i. e. carrying out geomechanics model tests on the single opening,caverns,slopes and foundation ditches,carrying out shear strength tests on the analogy sample of rock mass reinforced by prestressed anchor cables,and carrying out bending strength tests on concrete and reinforced concrete beam. The apparatus can rotate model in two directions,i. e. 360 degrees rounding its rotation axis and 35 degrees in a straight plane. The apparatus adopts about 10 piston-type uniform pressure loaders successfully to make a large uniform strain field in the model of openings and non-uniform range merely within 10 cm distance to the boundary of model. It also can apply uniformly distributed load or ladder type load to the boundary of the model with different lateral pressure coefficients,to obtain quasi-plane strain conditions and give the whole process curves of t-u in the shearing test. The apparatus has been used to carry out six engineering tests and the test results are all satisfactory. The presented apparatus is of wide utilizable prospect in large-scale model tests for the research and design of national defence projects,civil defences and other civil projects in the future.