Mechanical Response Analysis On The Cement Pavement Considering Cavity Beneath Slab

Cavity beneath slab is one of the common damages of the cement concrete pavement. Especially when the position of cavity beneath slab is in the corner, the pavement slab with corner cavity is likely cantilever plate. Under the vehicle loads there is very large stress and deflection at the edge of the pavement, which have a serious influence on pavement performance.At present, the cement concrete pavement design methods in our country don’t include the effects of Cavity beneath slab, which result in easy destruction of pavement. Therefore, it needs the cement pavement design method considering cavity beneath slab to improve the existing design theory. However, it can provide the theoretical analysis basis for the cement concrete pavement design method considering cavity beneath slab to calculate the deflection and stress of pavement considering Cavity beneath slab.This paper introduces two methods for calculating the deflection and stress of pavement considering Cavity beneath slab---the analytical method and numerical method. And focus on the analysis of pavement considering Cavity beneath slab by numerical method. The three-dimension finite element analysis model is built in this paper by software of ABAQUS. The calculation results are shown when the corner of slab bottom appears cavity. The deflection is significantly increased by the side length of cavity surface. Further analysis shows that, the relation between deflection and the side length of cavity surface is in exponential form. As to cavity in the middle longitudinal joints, the relation between deflection and the side length of cavity surface is exponential form, too.Through the analysis of finite element calculation result of different cavity size, the expression between the deflection of cavity beneath slab pavement and the side length of cavity surface is given; the calculation and analysis result of deflections of different slab thickness, the expression between the deflection of cavity beneath slab pavement and the slab thickness is also presented; The calculation and analysis result of deflections of different slab thickness, the expression between the stress of cavity beneath slab pavement and the slab thickness is obtained. Finally, the advantages and disadvantages of the analytic method and numerical method are discussed. The meaningful conclusions based on the calculation and analysis of the cement pavement beneath with cavity can be as a certain reference function for the design theory of cement pavement.