滇池湖相沉积软土场地基坑安全分析

Foundation pit safety analysis of lacustrine deposits in soft soil area of Dianchi Lake

以某深基坑工程为例对其事故原因进行分析,深基坑支护设计为围护排桩+一道钢筋混凝土内支撑支护结构,内支撑布置为椭圆形大圆环中部桁架的支撑体系。因土层地质差、立柱桩沉降、立柱桩间距过大及基坑边缘大量堆土,导致开挖过程中支撑体系局部变形、对撑梁跨较大的跨中部位出现了明显下挠、对撑梁支撑点处出现裂缝及围护桩出现偏移等。通过增补立柱桩、移除堆土等处理措施,加强对撑结构的强度及稳定性,并运用Midas/Gen有限元软件模拟立柱桩沉降,对事故进行分析,为此类场地上的基坑工程的设计及施工提供指导。

Take a deep foundation pit project as an example to analyze its accident causes.The deep foundation pit support is designed as a supporting structure with a row of piles and a reinforced concrete internal support structure.The internal support layout is a support system consisting of an elliptical large ring and a central truss.Due to the large amount of soil piled at the edge of the foundation pit,the poor soil geology,the settlement of the pillar piles,and the excessively large spacing between the pillars and piles did not meet the expected requirements,the retaining piles were offset,and the supporting system was partially deformed during the excavation process.The large mid-span has obvious deflection and cracks at the supporting point of the brace beam.The strength and stability of the bracing structure were strengthened through the treatment of the supplementary column piles,and the cause of the accident was analyzed using midas/gen finite element software.The analysis of deep foundation pits in this article can provide references for the design and construction of foundation pits on such sites,which has certain guiding significance.