微型集群钢管桩在滑坡体基坑支护工程中的应用

Application of Micro-Cluster Steel Pipe Piles for Foundation Pit Support of Landslide Mass Engineering

目的研究设计非开挖护坡微型集群钢管桩在深基坑支护工程中的施工方案,并在建筑工程应用中验证其可行性.方法对位于已经通过治理滑坡体原抗滑桩下方的某地一高层建筑的基坑支护工程,设计了微型桩群+锚索横梁+挂网喷锚结构、三纵四横的阵列布置方式;根据弹性地基梁的"m"法通过微型桩抗滑桩受力模型转换为由单根微型桩受均布荷载模型和刚框架顶部受集中荷载模型的计算叠加得出抗滑桩内力的计算方法,由深基坑岩土相关软件计算出微型桩体系的抗剪切、抗弯曲内力及最大位移.结果施工后经对桩体变形监测得出,累计平均整体位移数值15.1 mm,小于《建筑基坑工程监测技术规范》(GB50497—2009)位移预警值30 mm,微型桩群设计方案技术指标符合国家规范要求.结论对于近距离周边有滑坡体的深基坑开挖采用非开挖护坡微型集群钢管桩的深基坑支护施工设计方案是完全可行的.尤其在大型机械不能到达的边坡、空间狭小的位置有着很强的适用性.

A construction scheme of non excavation micro-cluster steel pipe piles for deep foundation pit support of landslide mass engineering was studied and its feasibility was verified in construction engineering. For the foundation pit support of a high-rise building in the excavation project located in the landslide governance which has passed the original anti-slide pile below the original anti-slide pile, a micro pile group ＋ anchor beams ＋ hanging spray anchor structure with three vertical and four horizontal array arrangement was designed. Using the elastic foundation beam ＂m＂ method which transfers the anti-slide pile force model into a uniform load model of single micro-pile and a concentrated load model of the top rigid frame, anti-slide internal forces can be calculated. Shear and bending forces and the maximum displacement of micro-cluster steel pipe piles can be obtained. It is found that the overall average displacement value of the pile is 15. 1 mm, which is smaller than the displacement alarm value 30mm, according to（（Technical Code for Monitoring of Building Foundation Pit Engineering）） （GB50497-2009）. Conclusion is that the proposed design scheme is reliable for the landslide close surrounding with deep foundation pit;especially it is very applicable for the narrow space and slope where the large machinery can not be used.