Study On The Design Of 800kN Fabricated High-strength Concrete Prestressed Slope Anchorage Beam

Prestressed anchor cable frame beams have been widely used in slope reinforcement projects in water conservancy,mining,railway and other fields.At present,cast-in-place frame beams are mainly used in China,which have the disadvantages of long construction period,poor quality,low anchoring force in design.Landslide accidents are prone to occur during construction.The prefabricated slope anchorage beam can be manufactured and maintained in the factory.It can be directly hoisted and anchored after being transported to the site,which can complete the slope reinforcement in a short period of time and reduce the construction risk factor.This construction method has the advantages of high degree of mechanized construction,short construction period,economy,beauty and durability,and it is also suitable for emergency reinforcement of slopes.There are few domestic researches on prefabricated anchorage beams,and special design specifications have not been formed yet.In-depth research is needed on the design methods of prefabricated anchorage beams.This paper takes the prefabricated high-strength concrete prestressed slope anchorage beam as the object,and studies the mechanical calculation model,design calculation method and finite element simulation during the hoisting and anchoring stage of the anchorage beam.The main research contents and conclusions are as follows:(1)Summarizing the analytical solution of Winkler elastic foundation beam under concentrated load and the related finite difference solution.On this basis,the finite difference solution of inverted T-shaped variable cross-section beam under concentrated load is derived,which can provide theoretical support for the structural optimization and design calculation.(2)Based on the reasonable calculation of the internal force of the inverted Tshaped variable cross-section anchored beam,according to the existing design specifications,a set of design theory for the prefabricated anchorage beam with prestress is summarized.12 types of inverted T-shaped variable-section anchorage beams,which suitable for 800 k N anchoring force,were designed according to this design theory,and the structural dimensions of these beams are given in the form of figures and tables.(3)ABAQUS was used to analyze the stress and deformation of the anchorage beams during the hoisting and serviceability stage,and there were no cracks in anchorage beams during these two stages,which verified the rationality of the structural design method.The simulation results show that when using two-point hoisting,it is more advantageous to set the hoisting rings at a position with 1/8 of the beam length from the beam end;There are always stress centralizations at the position of web width change and intersection corner of node.Therefor smooth transition sections should be designed there;Doubly reinforced sections should be adopted because of the interchange of the positive and negative bending moments during the hoisting and serviceability stage.(4)Compared with rectangular cross-section beams,the inverted T-shaped variable cross-section anchorage beams have a smaller internal force and more reasonable distribution under the same anchoring force because of the smaller overall rigidity.the inverted T-shaped variable cross-section anchorage beams have a higher utilization rate of material and lighter structure,but without reducing the structural bearing capacity.So it is more reasonable to use this kind of cross-section to design the anchor beam.