Influence Research Of Shallow Buried Pipe-Jacking Crossing On The Pavement Structure And Soil Base

As an important subsidiary facility to improve the function of the airport,the buried pipelines in the airport play an important role in the operation of the airport.For the airport that has been used for years,there are a lot of pipeline reconstruction demands in the process of reorganization and expansion.As a representative of trenchless technology,pipe jacking method is widely used in the reconstruction of airport pipeline network because of its small interference to the flight area.However,because of the shallow depth of the pipeline,the disturbance effect on the soil foundation in the process of excavation is inevitable.Therefore,a full section optical fiber monitoring is carried out on the top of excavation surface to study the influence on the soil base and the pavement surface.Based on the image method,a theoretical model of soil disturbance is established,and a Matlab program for calculating ground settlement is compiled.The influence of excavation disturbance under different ground loss and different construction parameters is discussed.A set of model tests were carried out and distributed optical fiber monitoring technology was applied to measure the ground settlement,soil strain,strain and supporting force under the pavement during the excavation.By contrast,in the ABAQUS software,a group of pipe jacking finite element model,which considering the influence of pavement structure is established to analyzes the influence of different operating parameters and different constraint conditions.The theoretical model was modified and verified using the finite element model results.The main conclusions of this paper are as follows:(1)Pipe jacking will produce certain strain and settlement deformation in the ground.The soil at the top of the excavation face will produce a large pressure strain,and the soil on both sides of the excavation will produce a certain amount tensile strain.The law of ground settlement in the soil is still in accordance with the Peck settlement trough,and the settlement curve is in the form of normal distribution.(2)Due to the different construction parameters such as pipe diameter and buried depth in pipe jacking,the disturbance effect is different.With the increase of the pipe diameter,the effect of excavation on soil disturbance is more intense.The overall performance is that the peak value and the influence width of ground settlement and stratum strain are larger,and the settlement and strain curves have a linear correlation between the peak value and the influence width.(3)Due to the influence of excavation,the supporting force of the soil above the pipe will decrease.The bottom of the pavement will produce a certain amount of tensile strain due to the uneven support of the soil foundation.The effect of the uneven support decreases with the increase of the buried depth of the pipeline.(4)Due to the constraint of the pavement to the soil foundation,the influence range of the settlement curve increases in the soil layer,and at the far distance from the excavation face,the settlement size increases slightly than the free surface deformation of the soil foundation.By using the modified calculation model,the displacement of soil settlement calculation under constraint of the pavement is more accurate...