Cause Analysis and Countermeasures of Through Shakes in Foamed Concrete Subgrade

摘要

The paper presents a new type of materialfoamed concreteadopted for expansion subgrade of the expressway. Intriguingly, the irregular through shakes appear on its top. The method combining the engineering case, theoretical analysis, and numerical simulation is employed to analyze its T-shaped and tree-shaped through shake. The research indicates that when the underground water table is high, cracks are easily seen on the top of step-shape foamed concrete due to buoyancy force. Under the concentrated load effect, the maximum displacement of 27.09mm is observed on the top of the simply supported beam when elastic modulus is 200MPa. The maximum principle tensile stress of 0.34MPa also occurs on the top of the simply supported beam when elastic modulus is 200MPa and 400MPa, which is greater than tensile strength of foamed concrete of 0.31MPa and 0.26MPa at 7d and 28d, respectively. Thus, the adoption of a simply supported beam structure fits site through crack. To avert cracks on the top of foamed concrete in high groundwater table, the antibuoyancy measures should be adopted prior to construction of the upper bearing stratum. The study has expanded the application scope of subgrade and enriched theory of foamed concrete filled in high groundwater table, providing a significant reference to similar projects.