Research On Gradation Design And Performance Of Cement Stabilized Macadam Of Framework Dense Structure

The bowl-type temporary support structure is a commonly used formwork support frame,which is widely used in engineering construction.However,with the increase of the formwork support frame and various reasons,the formwork support safety accident sometimes occurs.Although domestic and foreign scholars have done a lot of research on the bowl-type temporary support structure,there are still some shortcomings.There are two main points.The first is that the rigidity and true bearing capacity of the bowl-type temporary support structure are not well studied."It is not reasonable to stipulate the setting of the bowl-type temporary support structure.As a result,the template support frame is set up with subjective experience,which makes the template bracket unscientific and non-standard,resulting in a large number of safety accidents.In view of this,the main research work of this paper includes:(1)Analyze the cause of the safety accident of the bowl-button temporary support structure.Investigate the failure of the domestic formwork support in recent years,and analyze the case of typical support instability.The reason for the instability of the formwork support is that the stiffness of the formwork support frame is uncertain,the “normative” regulations are not reasonable,and the bowl-button temporary support Insufficient structural bearing capacity.(2)Determine the range of rotational stiffness values of the bowl-button temporary support structure node.The structure of the button-type temporary support structure is studied,and the connection theory of different nodes is analyzed.It is shown that the calculation of the bearing capacity of the bowl-type temporary support structure is more reasonable with the node semi-rigid connection theory,and combined with the "normative" requirements,the bowl-button temporary support structure node is obtained.The rotational stiffness value is reasonably in the range of 19 to 29 kN·m/rad.(3)Analyze the temporary support capacity of the bowl button.To this end,the overall simulation calculation model of the bowl-type temporary support structure was established,and the change of the bearing capacity of the bowl-button temporary support structure under different parameters was studied.The research shows that the bearing capacity of the template support frame decreases with the increase of the height of the sweeping rod and the vertical rod protruding from the top of the sweeping rod.The reduction of the step distance and spacing of the vertical rod can improve the bearing capacity of the bracket,and it is proposed to set up the bowl button type on the basis of research.When the temporary support structure,the sweeping rod should not exceed 0.4m,the height of the vertical bar should not exceed 0.5m,the spacing of the pole should not exceed 1.2m,and the step should not exceed 1.2m.