盖挖法托换技术在沈阳站地下通道工程中的应用

通过对沈阳站东站房地下通道工程开挖过程的数值模拟,对基坑开挖过程中地面沉降、支护桩的变形、立柱的内力和下卧地铁区间的变形进行了计算分析.结果表明,托换板可以有效地限制支护桩的水平位移和基底土体的隆起,进而控制地表沉降的产生;基坑开挖过程中所引起的基底土体隆起会使立柱自身的轴力增大,影响内支撑结构体系的稳定;基坑开挖对其下卧地铁区间的水平、竖向位移有明显影响,区间以"水平向压缩、竖向拉伸"的椭圆形形式产生收敛变形.交叉建设的基坑工程对周围环境及建构筑物的影响不容忽略.

Underpinning Technique Based on Cover-Cut Method for Underground Passage Project at Shenyang Railway Station

The excavation process of the underground passage under the east station house at Shenyang station was simulated by FEM. The land subsidence， deformation of retaining piles， inner force of stand columns， and the deformation of underlying tunnel were analyzed. The results show that underpinned plates can limit the horizontal displacement of retaining piles and the upheaval of the pit bottom effectively， thus controlling the land subsidence. The upheaval of the soil at the pit bottom caused by the excavation process leads to the increase of the axial force of stand column， which may affect the stability of the support structure system. Moreover， the excavation process has an obvious effect on horizontal and vertical displacement of underlying tunnel， where one kind of convergent deformation happens in the tunnel in the form of ‘the horizontal compression and the vertical stretch’. The impact of the cross constuction of foundation pit on the ambient environment and structures cannot be ignored.