Influence Research Of Underground Pipeline Tunneling On The Safety Performance Of Airport Pavement Structure

With the accelerating process of modern airport construction, the extension and reconstruction of underground pipeline, which meanwhile is confronted with the limitation requirements that can't affect the normal operation of airport and thus making trenchless construction the only way to cut through the underground in the pipeline construction, need to be done continually in the existing flying area. Pipe jacking method is widely used at present in the underground trenchless construction with a larger cross section, which will inevitably produce disturbance in the surrounding soil, resulting in additional stress and deformation of soil mass. Furthermore, most of the underground pipelines are constructed under the pavement which is in running state, once cross-over construction makes soil displacement too big, it's possible to make superstructure disturb exceedingly, even endangering the safety of the runway and aircraft running in the runway.To prevent excessive deformation of the pavement and harm to plane that may be caused by underground construction, scientific analysis about soil disturbance caused in the crossing process is needed in the program development of engineering construction to evaluate the impact of construction process on the pavement. Therefore, based on the mechanism analysis of soil displacement and pavement failure caused by pipe jacking, the effect law of buried pipe jacking in the airfield on the pavement is discussed and the impact analysis model of underground crossing process on the superstructure is built to provide scientific methods for the reliability assessment of the effect of pipe jacking construction process on the runway.In order to scientifically express the disturbance effect of pipe jacking on the surrounding soil and pavement, based on finite element method, the effect factors and laws of pipe jacking on soil disturbance and soil deformation, supporting condition under the pavement and stress and deformation of runway are studied. Disturbance distribution and influence scope caused by pipe jacking, change of soil support stiffness under the runway and horizontal stress and vertical displacement of the runway are analyzed. By applying the plane loads, the most unfavorable construction condition of pipe jacking method is discussed. By establishing the finite element analysis model, the parametric analysis of pipe jacking construction is discussed, including soil mechanics parameters, pavement mechanics parameters, pipe parameters, grouting pressure and load forms, etc. The results show that the factors above have significant influence on the stress and deformation of pavement and may cause structure failure in severe case. Based on these results, the corresponding prevention measures from the aspects of construction craft and construction technology are given, providing reliable scientific method for developing technical proposal of non-suspend air construction in the airfield.