深基坑开挖对下方隧道两侧抗浮桩侧摩阻力的影响

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中图分类号：TU473 文献标志码：A

Abstract：To address the isue of underlying tunnel uplift caused by unloading during excavation of deep foundation pits， taking a dep foundation pit projetin Beijing Cityas aresearch object，and MIDAS GTS NX software as afiniteelement modeling tol，anengineering model without anti-floating measures was established.Bycalculating vertical displacementsof aunderlying tunneland groundsurfaceinthemodel，necessityofaddinganti-floating measures totheproject wasanalyzed， andan enginering model with anti-floating measures was then established.Bycalculating vertical displacementsof the underlying tunnel and ground surface in the new modelandcomparing with field monitoring data，accuracyof the new model wasverified.Vertical displacementatthetopoftheuplift pilesobtained from simulation calculation inthe new model was extracted toapplyto single pile modelsand lateral friction resistanceof uplift piles was calculated.Roleand influence mechanismof lateral frictionresistanceof uplift pilesonboth sidesof the tunel underthedeep foundation pit were thus disussed at diferent excavation depthsand grouting effectsaswellas different deep foundation pit positions. Theresultsshow thatanti-floating measurescombinedwith groutingcanefectivelyinhibittunnelupliftduringdeep foundationpit excavation.Excavationdepth impactsrelativedisplacementbetween pileandsoil，therebyafects lateralfriction resistance ofuplift piles.Grouting improves soil compaction，thus allowing forbeterutilizationoflateralfrictionresistance. Lateral frictionresistance of uplift piles nearthecenterof thedep foundation pitcanbe exerted rapidlyand completely， while lateral frictionresistanceof uplift piles neartheedge is exertedslowlydueto constraint of inner wals inthe deep foundation pit.There is a phenomenon that lateral friction resistance of some uplift piles is not fully exerted.

Keywords：tunnelanti-floating；lateral friction resistance；finite element simulation；uplift pile；deep foundation pit

随着我国城市建设的快速发展，可利用的土地资源日益减少，不可避免地出现了大量新建筑物位于隧道上方的情形，其中不乏大量超高建筑和大体量建筑群[1]。（剩余11857字）