Method Of Deflection Basin Shape Factor In Recognition Of Voids Under Rigid Pavement

Void under the rigid pavement is one of common constitutive damages. For the rigid pavement's road surface in use, partial foundation void phenomenon exists in large quantities. It will extend gradually if the void area is left without handling timely. Otherwise, pavement surface will cracks and staggered. It may cause smash and sedimentation of the pavement surface when the void is serous. Therefore, how to use the effective method to detect the rigid pavement surface and how to judge if there is void under the pavement surface and determine the size of it have become the key of the pavement maintenance work.At present, both at home and abroad the voids spatially to the rigid pavement is mainly the qualitative judgment, to escapes the spatial size the research to involve are very few, the spatial quota judgment voids also to be at the exploration stage. Therefore this article mainly aims at the above existence the question, the research and the discussion useing FWD quota judgment rigid pavement escapes spatially.Based on the FWD principle of work, this article unifies the existing no-damage test technology of the pavement, and carries on the computation analysis of the deflection distribution of cement concrete road surface under FWD load by 3D FEM. During the process of building finite element mode, Winkler ground model was used and cutting spring was used to imitation the load-transferred capacity of seam. In view of static, dynamic load models, related physical mechanics parameter of computation model was adjusted and different computed result was recorded. It carried on analysis and comparison of the computed result.Based on analysis and comparison, according to the characteristic of deflection basin when the rigid pavement road surface has void for the board angle, this article proposed the void evaluation method—deflection basin shape factor. This article can estimate the size of the void area according to the actual deflection difference and proposed corresponding void detection method and measure.Through FWD examination data analysis of an airport runways' actual cement concrete pavement, it evaluates the condition of road surface void using void detection methods in this article. The results show that evaluation result in this article is in accordance with the three-point regression void detection on whether exist void. Thereby we had proven the validity and the usability of the void detection method which is proposed in this article. Compared with the existing rigid pavement void detect method, the method proposed in this article is characteristic of easy use. It can estimate the size of void, and is of important reference value for guiding the road surface rehabilitation work.