Preventive Technology Of Unstable Rock And Rockfall Hazard At Tunnel Entrance In High And Steep Slope

In this thesis, the author chooze rockfall hazards at tunnel entrance as research object and complet the following work:Numerical simulation of the slope movement about falling rocks, disaster risk classification and decision assessmentof rockfall at tunnel entrance, the layout of the tunnel entrance in the area threatened by rockfall and rockfall disaster prevention etc..The following results were obtained:(1) As the slope angle increases, the rockfall at the foot of the slope of the more recent placement, the bounce height increasing.The platform have a roll in rockfall energy dissipation. The greater slope angle, slope effect of energy dissipation is significantly reduced.The closer the foot of the slope, falling rocks in the faster the energy loss of the slope movement.(2) On the convex curve, the rockfall movement in the first stage is to scroll as the main, through the second and third stages are obvious projectile, with little slope effect, and most have significant secondary bounce. On the convex curve the rockfall will eventually enter the projectile state.(3)The author suggests that the preliminary evaluation criteria of rockfall. Researching the various factors of development of unstable rock and dividing them into two levels. The first level of topography, lithology, meteorology and hydrology, structure, surface development and other factors.Factors Influencing the development of analytic hierarchy process model to establish the dangerous rock,And asked the unstable rock developmental level of the evaluation of various factors and criteria.Establishing a unstable rock developmental fuzzy membership function and introducing the method of AHP-Fuzzy comprehensive evaluation.(4)Cuducting initial evaluation of the development of unstable rock at the Persimmon Park Tunnel entrances, and carry out a detailed assessment the tunnel exit. Comparing each factor of unstable rock development at the exit section and getting the Analytic Hierarchy judgment matrix.In accordance with the unstable rock evaluation grades and standards, the author scores various factors of development of various factors and cuducts AHP-Fuzzy comprehensive evaluation on unstable rock developmental risk at the Persimmon Park tunnel entrance and proposes protection recommendations.