The Research Of Void Evaluation Techniques Of Beneath Cement Pavement Based On Finite Element Analysis

Void beneath slab is one of the common damages of the cement concrete pavement. The void is on the slab beneath, which is extremely unfavorable for the force of cement concrete pavement. Under the load function, the void place will be appear the phenomena of stress concentration, because the early time appeared void can not discovered form pavement, the void will develop gradually in use of pavement, in addition the loads of heavy vehicle is on the pavement repeatedly, which eventually lead to the rupture of the pavement, and affecting road driving conditions. Therefore the judgment that the void is or not on pavement is particularly important, but according to the current domestic analysis and research shows that effectively carry out the void evaluation of cement concrete pavement is very difficult.This paper first uses Westergaard theory to confirm the correctness of analysis the void of cement concrete pavement with ANSYS 3D finite element, after applying ANSYS software to establish road and foundation support model based on the actual parameters of the pavement structure, and the assumption there are the certain area void in the angle of slab and the middle of slab brim, and the load should be same with the load of FWD, afterward, in the postprocessing of ANSYS look at the deflection of the detection point, if the measured deflection value of FWD at the center more than or equal to the software calculated the deflection value, may initially conclude that there is void which is suitable with the hypothesis shape area underneath the road slab , or the void area is bigger than the hypothesis, according to this thought to bring forward the way of the evaluation void.Analyze the void of cement concrete pavement in the course of testing in the highway of Heilongjiang Province by this method, and estimate the void is in existence by ground penetrating radar and verification of drilling, and the result is match with actual situation. use this method could quickly evaluate the void of cement concrete pavement is in existence or not and the area of void by the project.