复杂工况下超大型人工堆山与邻近工程施工时序耦合影响研究

Coupled Effects of Construction Sequence between a Super-Large-Scale Artificial Hill and Adjacent Engineering Works under Complex Construction Conditions

摘要: 为研究人工堆山及不同施工顺序对邻近基坑变形的影响，采用MIDAS GTS NX建立堆山–基坑三维有限元模型，设置仅开挖基坑、基坑–堆山同步施工、先开挖后堆山和先堆山后开挖四种工况，对靠山侧地表沉降、两侧拉森钢板桩侧向位移及坑底隆起进行对比分析。结果表明：堆山显著增大靠山侧地表沉降和钢板桩侧向位移，同步施工和先开挖后堆山工况的不均匀沉降更为突出；远山侧位移因距离衰减及基坑开挖对浅层传递路径的削弱而明显小于靠山侧；四种工况的最终坑底隆起量较为接近，施工顺序主要改变变形的发展过程和增长速率。研究结果表明，不同工序对应的主要变形控制指标不同，工程评价应综合考虑沉降量、沉降差、两侧围护结构位移及坑底隆起。

Abstract: To investigate the effects of artificial hill piling and construction sequence on the deformation of an adjacent foundation pit, a three-dimensional finite element model was established using MIDAS GTS NX. Four cases were considered: foundation-pit excavation only, simultaneous excavation and hill piling, excavation followed by hill piling, and hill piling followed by excavation. Ground settlement on the hill side, lateral displacement of the sheet-pile walls on both sides, and basal heave were compared. The results show that hill piling markedly increases hill-side settlement and lateral displacement, while simultaneous construction and excavation followed by piling produce more evident differential settlement. The far-side response is smaller because of distance attenuation and the weakening of the shallow transfer path caused by excavation. The final basal heave is similar among the four cases, although the construction sequence changes its development process and growth rate. The results indicate that the principal deformation control indicators vary with the construction sequence. A comprehensive assessment should therefore consider settlement, differential settlement, wall displacement on both sides, and basal heave.