地下环线结构体上盾构吊装设计与选型评价

Hoisting Design and Selection Evaluation of Shield Machine on the Underground Loop Structure

依托济南中心商务区绸带公园站盾构机接收工程为背景,通过MIDAS三维数值模拟和现场实测,重点研究城市轨道交通交叉施工中,选用既有地下道路结构作为接收或始发井,将盾构从吊出井起吊、盾构机起吊挂钩顺时针旋转90°、盾构放置在放置平台上及利用500t汽车式起重机将盾构装车4种工况下地下环线结构受力及变形问题。4种工况研究表明,盾构刚起吊出井时,作用在地下结构的偏心荷载不利作用最明显,会造成地下环线结构发生较大累计沉降和差异沉降,而后在起重机旋转过程中,地下环线结构差异沉降及累计沉降呈微小减小趋势。地下环线西侧填土会使地下环线结构侧墙与底板应力增大,且这种影响会危及结构安全。在4种工况转换过程中,地下环线顶板最大主应力均出现在板与柱交界处,且其位置不会随起重机臂旋转而发生变化。

Based on the shield machine receiving project of Ribbon Park Road Station in Jinan Central Business District,through MIDAS three-dimensional numerical simulation and field measurement,this paper focuses on the selection of the existing underground road structure as the receiving or originating shaft in the cross construction of urban rail transit,the stress and deformation of underground loop structure are discussed under four working conditions of the shield machine hoisted from the shaft and the shield machine lifting hook rotated clockwise for 90°degrees,placing shield machine on the platform and loading shield machine with 500 t truck crane.The results show that,when the shield machine is just hoisted out of the well,the adverse effect of eccentric load on the underground structure is the most obvious,which will cause large cumulative settlement and differential settlement of the underground loop structure.Then,during the rotation of the crane,the differential settlement and cumulative settlement of the underground loop structure decrease slightly.The filling on the west side of the underground loop will increase the stress of the side wall and the bottom plate of the underground loop structure,and this effect will endanger the safety of the structure.In the process of four conditions conversion,the maximum principal stress of the underground loop roof appears at the junction of the slab and the column,and its position will not change with the rotation of the crane boom.