The rockburst (rock burst) is a peculiar, abnormal, localized, isolated, delayed, sudden and damaging phenomenon associated with the underground rock excavation. Several hours after the completion of the excavation, some parts of the in-situ intact rock wall might be actively, suddenly and vigorously ejected, thrown and blown off from the original wall into the excavated open space, with high initial ejecting velocity and kinetic energy. It often causes fatality, injury and damage because its occurrence is usually unforeseeable and unpredictable. The rockburst is still a worldwide tough problem that puzzles the international communities of rock mechanics in spite of tremendous research efforts over the past 50 years. This paper puts forward a hypothesis of micro-fluid inclusions as the cause and mechanism of the rockburst. The fluid inclusions in the micro-voids of intact rocks may have a high initial pressure equaling to the average of the three in-situ principal stresses. The fluid inclusions with a high initial pressure can have a high expansion power. They can flow, migrate and turn from the liquid phase into the gas phase after the rock excavation. Their physical and chemical expansion power can cause the rockburst of the excavated intact rock wall. This hypothesis offers effective solutions for the rockburst problem to reduce and eliminate its damage.
This paper reviews the developments of the Timoshenko beam theory with consideration of the shear deformation, the calculations of the shear correction factors, the linear and geometrically nonlinear finite elements of the Timoshenko beam, the material nonlinerity analysis, the vibrating theories, the stability theories, the coupling theories of the shear lag and the shear deformation and the coupling theories of the distorsion and the shear deformation in a box beam, the shear deformation effect on the composite box girder with corrugated steel webs, the elastic foundation beam, and the applications in civil engineering.