Studies On Carrying Capacity Of Rigid Pavement Based On Displacement Field In Conditions Of Aircraft Taxing

As major infrastructure for aircraft takeoff and landing, airport runways’ detectionreliability of carrying capacity is directly related to the safety of aircraft operations. At present,in most cases the detections concerning carrying capacity of airport runway are adopting theheavy weight deflectometer (HWD) technology, during this method the heavy hammer’spercussion is used to simulate effect of the single wheel load acting on pavement. However,the simulation load is far smaller than the actual aircraft total load, so there is notcoMParability between them on both size and influence depth. In addition, the test can onlybe conducted in conditions that runway is closed, but in large and busy airport aircrafts takeoff and land day and night, gaeat economic and social influence will be brought because ofrunway’s closedown. So how to evaluate carrying capacity of the runway reasonably withoutsuspending flight is still a big problem for aviation engineering.This article is completed under supporting of National Science Technology Foundation.By considerable finite element simulations and theoretical analyses,a new system that is usedto evaluate carrying capacity is presented, the system regards acquisition of oscillationacceleration from paving during aircraft taxing as the test method, the system looks on themeasured dynamic displacement inversion paving hierarchical struction as the core, Themain work and achievements are as follows.1. In consideration of the parameters’ effect of paving unevenness、the aircraft lift、taxiing speed etc, The airplane dynamic load coefficient model is established, which is basedon International Roughness Index (IRI).This model can analyze the real-time force on thepavement in the process of taking off and landing.2. Initial finite element model based on the elastic layered system is establish, and itconsiders the influence of seams between road panels which are simulated by spring unit inorder to transfer shear.At the same time,the model’s accuracy has been verified. Thereasonable criteria is selected to explore the influnent depth of fundation under differentaircraft dynamic loads, so that the fundation thickness of subsequent finite element modelingcan be determined. The results show that the fundation influent depth is affected by pavementstructure, the structure type of main landing gear and aircraft weight.3. The deflection curves of the full width of pavement are calculated under different loadpositions relying on finite element software. The elastic moduluses of surface course, subbasecourse, base course and subgrade are adjusted successively with variables control method.And corresponding displacements are calculated, therefore, displacements in test area variations are got. Key control parameters are determined in the process of strength inversionof each structrual layer. The mathematical models of vertical displacements and surfaceelastic modulus, vertical displacements and subgrade elastic modulus, vertical displacementsand surface thickness are established relying on a large number of the finite elementcalculation results. The conversion relationship model between based top resilient modulusand based top reaction modulus is set up, so the resilient modulus can transform into reactionmodulus, which provides theoretical basis for carrying capacity calculation programming.4. Non-destructive testing programs without suspending flight about pavement’s strengthare put forward. The new inspection techniques are applied in the two different level airportsin North China and Yunnan Province. It proves that the detecting means and theories arefeasible and got good project effectiveness.