反压土和中心岛式开挖在某深大基坑工程中的应用

Application of Reverse Pressure Soil and Central Island Excavation in Deep and Large Foundation Pit

为了减小坑底隆起、支护结构过大位移以及增强稳定性,反压土和中心岛式开挖模式被广泛应用于深大基坑施工。文章采用数值模拟方法,以合肥大学城地下工程为例,研究了反压土和中心岛式开挖联合使用对支护结构、位移和稳定性的影响。研究表明,反压土和中心岛式开挖联合使用能大幅度减小各施工步支护结构的内力和基坑变形,通过设置三道斜撑,在其中预留反压土开挖来降低施工过程中引起的土体沉降,减少了开挖工序时支撑与反压土的相互干扰。采用此种方式可增强基坑整体稳定性,经济合理,施工效率较高,为深大基坑的施工提供参考借鉴。

In order to reduce the uplift of the bottom of the pit, the excessive displacement of the supporting structure and enhance the stability, the reverse compacted soil and central island excavation mode are widely used in the construction of deep and large foundation pit. In this paper, the numerical simulation method is used to study the influence of the combined use of reverse pressure soil and central island excavation on the supporting structure, displacement and stability, taking the underground project of Hefei University City as an example. The study shows that the combined use of reverse pressure soil and central island excavation can greatly reduce the internal force and foundation pit deformation of the supporting structure in each construction step, and set up three oblique braces, in which the reverse pressure soil excavation is reserved to reduce the soil settlement caused by the construction process. the mutual interference between support and reverse pressure soil in the excavation process is reduced. The use of this way can enhance the overall stability of the foundation pit,economic and reasonable, high construction efficiency, and provide a reference basis for the construction of deep and large foundation pit.