Based on nearly 100 test specimens from different locations

different depths and different degrees of weathering

under the conditions of different concrete strengths and different water contents

the direct shear.tests have been done. The relation among shearing strength of rock and concrete strength

weathering degree and water content have been studied. The test results show that the concrete strength affects the shearing strength of rock and concrete greatly. The contact shear strength is nearly equal to that of massive structure and sub-massive structure

and thear strength values reduce greatly to that of clastic structure and inter locked structure. The cracking location is not contact area of rock and concrete but partial contact plane and partial structural plane. With the water content increases

the cohesion force and inter-friction degree decreases. Laboratory shear test results only reflect the location of specimens. To gain the contact plane shearing strength

the cohesion force and inter-friction degree is looked as stochastic variables. Regionalized variable and variogram are introduced to represent the rock randomness and structure. Kriging equation is used to calculate weight values of test specimens. At last

the shearings strength of rock and concrete are obtained by statistical method.