the German goldsmith Gutenberg invented the printing press including ink, printing, a set of metal printing , at the same time, the first press of the West was established.

Analysis of three probability models between trace length and diameter of rock discontinuities;

Various interface elements are successfully applied in traditional finite element method(FEM) to model discontinuities,in which Goodman element is the most representative one.

Analysis of influence of discontinuous plane on strength of rock mass based on unified strength theory;

There are a lot of discontinuous planes in rock mass of Longtan hydropower station underground power-house,so it is of practical value to make certain whether there are unstable blocks on excavation planes where faults and joints interlace with each other.

For the research on shear deformation characteristics of the discontinuous plane, the hyperbolic function is adopted to describe the shear deformation curve, and the key factors are discussed.