Study On The Influence Of Adjacent Bridge Piles Due To Construction Of Shallow-buried Excavated Station Tunnel With Large Cross-section

Based on the Chenjiaping station station project of Chongqing Rail Link Phase II project, this paper uses MIDAS GTS NX to simulate the deformation law of strata tunnel excavation through extensive extensive access to relevant literatures at home and abroad, and further simulate the shallow buried large section Influence of Tunnel Tunnel Excavation on Bridge Pile with Different Position and Pile Length. On the basis of this, the reliability of the numerical simulation results is verified by comparing the field monitoring data. The main conclusions are as follows:(1) In the tunnel excavation, the sandstone mudstone of the underlying bedrock is more effective than the sandstone in the sandstone mudstone. The vertical settlement of the strata conforms to the settlement law in the Peck formula and is normal distribution. The sedimentation center is the largest at the center of the tunnel excavation, and the horizontal displacement of the formation is 0 at the center of the tunnel excavation, and the settlement value is symmetrical and opposite in both directions. It is determined by the deformation law of the strata, and the main influence on the strata in the tunnel excavation cross section is between -2B to 2B(B is the tunnel excavation span).(2) Under the load of different pile tops, the vertical settlement of the pile increases with the increase of the pile top load, but the horizontal displacement is almost constant; the axial force of the pile increases with the pile top load, The force curve gradually slows down, the maximum bending moment of the pile increases with the pile load.(3) According to the relative position relationship between the bridge pile and the tunnel, the adjacent pile foundation in the main influence of the tunnel construction is divided into four types: the upper bridge pile, the upper bridge pile, the middle bridge pile and the lower bridge pile. By analyzing the different working conditions, the variation law of displacement and internal force of different types of adjacent bridges during tunnel construction is studied. Aiming at the different types of bridge piles, the corresponding suggestions are put forward for the design and construction of similar tunnels.(4) The relative position of the pile foundation and the tunnel is mainly determined by the length of the pile length s and the horizontal net distance x. The settlement analysis of the settlement of the pile foundation immediately after the tunnel construction is carried out to fit the settlement value of the pile foundation when the tunnel and the adjacent pile foundation are different.dv = 0.13sx-0.4+5.511n(x)-8.796 (4<|x|<40),The calculation formula can be used to estimate the settlement estimation of bridge pile foundation in similar engineering,which provides data support for tunnel construction caused by tunnel construction.(5) Based on the analysis of the settlement results of the pile foundation near the bridge and the results of the on-the-spot monitoring results, the reliability of the law is verified by the analysis of the construction of the Chenjiaping station, and the bridge is removed during the construction of the double- Pile foundation settlement of the pile accounted for more than 50% of the total settlement, so in the excavation of the core soil guide pit, the need to strictly control the construction progress, and do advanced pipe reinforcement measures.