Structure And Material Selection Of Small Precast Block Framework For Highway Slope Protection

Considering the stability of highway slope,as well as the coordination with environment,highway slope protection is combined with engineering protection and plant protection.At the same time with the development and promotion of precast component,slope protection structure made of precast block becomes a priority choice.There are three different shapes of framework: arch,herringbone and gridiron.Two kinds of most commonly used materials for precast block framework: mortar rubble leveling foundation and mortar leveling foundation.Two joint ways of precast block: buckle joint and flush joint.Various research methods such as numerical analysis,model experiment and field monitoring were used in this paper to analyze the slope protection structure made of precast block,in order to find the structure has best comprehensive properties,select most stable shape,material and joint way.A series of test of material strength has been made base on failure mechanism research of slope protection structure made of small precast block,reach characteristic value of framework bond strength,masonry mortar strength,base friction force.It applied to practical project need divide by a safety factor between 1.2-1.5.Eleven kinds of numerical models with different shapes,materials and joint ways were built to analyze equivalent stress,vertical displacement and lateral displacement of key points and slope lines,it shows that for the same structural material,the best shape is arch,for the same shape,the best structural material is mortar rubble foundation,in conclusion the structure with the best mechanical properties is framework slope protection structure have mortar rubble foundation and arch precast block surface.According to the conclusion of numerical analysis,four kinds of scale models with different shapes,joint ways and same mortar rubble foundation,were constructed according to1:4 ratio due to limited condition,loading and unloading step by step.Analysis on their stress and displacement of key points shows that: the best shape is arch,and the best joint way is buckle joint.According to the conclusion of numerical analysis,taking slope test section of Longcha Highway as the object of study,key points on three kinds of arch precast blocks were chosen to supervise the stress and displacement.It shows: the best joint way is buckle joint,and the best material is mortar rubble foundation.Summing up the numerical analysis,model experiment and field monitoring,the finalresult is: framework slope protection structure have mortar rubble foundation and arch buckle joint precast block surface comprehensive properties are best,it can emphasis promotion in actual engineering.