| At the construction of supporting facilities at the airport,limited to the special requirements of the above-ground space of the flight area,the development of underground space is becoming more and more important.When the oil pipeline,communication fire-fighting pipeline and water supply and drainage pipeline are constructed in the flight area,the airport is satisfied.The traditional open cut method is not applicable for non-stop construction requirements.Due to its low comprehensive cost,short construction period,low impact on the ground transportation environment and good construction safety,the pipe jacking method has been widely used in the construction of underground pipelines in flight areas.During the construction of the pipe jacking,it will inevitably cause disturbance to the soil within a certain range,which will cause the support at the bottom of the airport pavement to change.Once the deformation of the pavement is too large,the runway will be closed,and a major safety accident with a machine crash will occur.Therefore,it is extremely important to study the stress deformation of the pipe jacking through the lower airport road surface.Therefore,this paper analyzes the different movement modes of soil caused by pipe jacking excavation,determines the correction formula of soil loss caused by pipe jacking excavation,and corrects the soil movement mode by classical source-sink method.It is used to calculate the strain calculation formula at any point inside the soil,and the correctness of the theory is verified by a small indoor proportional test.Through the comparison of theoretical and experimental results,it is concluded that the strain is used as the monitoring index for the influence of pipe jacking excavation,which has higher sensitivity and better real-time performance.In order to simplify the calculation,the mechanical model of the pavement structure under excavation disturbance is constructed.The bending moments and displacements of the elastic foundation beam and the Winkler foundation beam under passive displacement are calculated respectively,and the laws of the two solutions are analyzed,and the foundation modulus under the excavation disturbance state is fitted.By analyzing the regular curve of soil settlement caused by excavation,the distribution law of the bottom support spring under excavation disturbance is obtained.With the above analysis,the spring beam model under excavation disturbance is established,and the stiffness variation of the pavement,the position of different aircraft loads,the different load impact coefficients,and the pavement deflection under different pavements are analyzed.The research results show that the above parameters have a great influence on the deflection of the pavement.When several unfavorable working conditions work together,the pavement will cause serious damage.Based on the finite element software,the deformation law of the airport pavement under different excavation steps,the thrust of the face and the friction of the face are analyzed,and the airport road under different construction parameters is discussed by the application of the aircraft load.Deformation of various structural layers and the law of influence range.The research results show that during the construction process,the face force should be controlled to minimize the friction between the pipe and the soil,so that the impact of pipe jacking on the airport road surface is minimized. |
