Experimental Study on the Stability Performance of Foamed Concrete Subgrade Structure in High-Speed Railway
[Purposes]In order to explore the feasibility of foamed concrete subgrade structure in high speed railway engineering,laboratory model test method was established to make the test.[Methods]The foam concrete layer is used to replace the large scale model for part of the foundation bed,and the long-term static and dynamic stability of the foamed concrete subgrade structure is tested by applying static load and constant frequency and amplitude dynamic load.[Findings]①When the surface height of the subgrade is the same,the additional stress at the measuring point decreases with the increase of horizon-tal and vertical distance between the measuring point and the loading point under static load,and the stress decreases significantly when passing through the foamed concrete layer.②The attenuation coeffi-cient of dynamic stress decreases and the value of dynamic stress decreases with the increasing depth of measuring point.Both graded gravel layer and foamed concrete layer have significant energy dissipation effect,and the degree of dissipation to dynamic stress of graded gravel layer is higher than that of foamed concrete layer than that of group A and B packing layer.③When the thickness of graded gravel layer is 0.5 m and 0.7 m,the cumulative deformation of foamed concrete layer under cyclic dynamic stress load-ing and unloading accounts for 3.18%and 3.80%of the total cumulative settlement,respectively.Foamed concrete as a whole packing does not produce large plastic deformation,the deformation is mainly caused by graded gravel layer.[Conclusions]The foamed concrete subgrade structure under load has good performance of reducing force,energy dissipation and deformation resistance.The research re-sults can be used as reference for similar engineering upgrading test parameters in the future.
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