Study on the Frictional Mechanical Properties of Curved Filling Interface of Rock Pipe Jacking

In order to verify the suitability and correctness of plane test and curved surface test in studying the frictional mechanical characteristics of pipe jacking in rock stratum under complex contact conditions, large-scale rock direct shear test was used to study the shear frictional characteristics between plane sandstone and new curved sandstone and concrete pipe under seven kinds of complex contact conditions. On this basis, the mechanical effects of pipe jacking under low contact height and variable contact conditions were numerically analyzed. The results show that the difference of the shape of the specimen results in the great difference of the effective friction angle between the plane test and the curved test. In numerical analysis, it is more reasonable to uniformly set the contact range of pipe jacking to 1/2 contact than 1/3 contact. By comparing the jacking force error of 1/2 contact condition in two types of tests, it can be saw that the average jacking force error based on the result of curved surface friction test is smaller than that of plane test. Finally, it is concluded that the curved surface test has better adaptability in the relationship between test conditions and the quantitative accuracy of test results.