地铁竖井深基坑与龙门吊轨道基础共同作用分析?

为合理设计地铁区间隧道竖井基坑支护方案和龙门吊基础，以厦门市轨道3号线某区间隧道竖井工程为研究背景，采用PLAXIS 3D岩土有限元数值分析软件建立竖井基坑、龙门吊轨道基础结构及邻近渣坑堆土相互作用的三维数值模型，模拟计算12种龙门吊荷载不同作用位置及偏压作用工况，结果表明：龙门吊行车作用下的地表最大沉降为4 mm，基坑围护墙结构最大变形值为16 mm，约为基坑开挖深度的0.64‰；基坑开挖变形引起的龙门吊轨道基础结构内力变化最大值为270 kN?m，变化幅度约为16.4%；周边堆土对竖井基坑变形及轨道梁内力变化量不超过13%，主要需满足未堆土工况下的侧壁自身稳定性；最后通过对基坑的监测数据分析，表明数值模型可靠，基坑总体上安全稳定，龙门吊基础设计合理，且有足够的安全度。

Analysis on the Interaction between Deep Foundation Pit of Subway Shaft and Rail Foundation of Gantry Crane

In order to reasonably design the supporting scheme of the shaft foundation pit and the gantry crane foundation of the Metro tunnel, taking the shaft engineering in Xiamen Railway Line 3 as the research background, this paper establishes a three-dimensional numerical model by using the 3D geotechnical finite element numerical analysis software PLAXIS to study the interaction of the shaft foundation pit, the gantry crane rail foundation structure and the adjacent slag pit . The conditions with 12 kinds of gantry crane loads at different locations and under eccentric loading conditions are simulated and calculated. Results show that the maximum ground settlement under gantry crane operation is 4 mm. The maximum deformation value of the retaining wall structure of the foundation pit is 16 mm, which is about 0.064 percent of the excavation depth. The variation of the internal force of gantry crane rail foundation structure caused by deformation of foundation pit excavation is 270 kN?m. The variation rate is about 16.4%. The variation of foundation pit deformation and internal force of rail beam caused by surrounding pile soil is no more than 13%. The design mainly needs to meet the side wall stability under the condition of no pile soil. Finally, the monitoring data of foundation pit shows that the numerical model is reliable, the foundation pit is generally safe and stable, and the gantry crane foundation is reasonable and safe enough.