FAST地锚基础工程中的若干问题探讨

Several Problems of Anchor Foundation Engineering in FAST Project

FAST工程主动反射面为一半径300 m、口径500 m的球冠面,是一种基于柔性基底的预应力整体索网结构,索网包括2225个主索节点及下拉索驱动装置和地锚。由于台址岩土单元复杂,地锚点多、分布范围广、定位精度要求高、与场地其他基础设施的相互干涉大,给地锚基础的设计带来了一定的难题。本文针对FAST地锚基础中的特殊问题一一展开研究:以工程地质调查和测绘为基础,通过抓台址区主控因素,集合影响台址岩土性质的自然因素,对岩土单元进行了合理的分区;通过建立台址开挖后的BIM模型,利用极射投影技术实现了地锚中心点的精确定位;利用极射投影结果,对设备之间的相互干涉情况进行了调节和处理。研究成果最终确保了FAST地锚基础工程的顺利竣工。

FAST active reflector is a spherical cap with radius of 300 m and diameter of 500 m,and it is a kind of prestressed cable-nets structure as a whole which based on flexible base. The cable-nets structure have included2 225 main cable nodes,downhaul driving devices and ground anchors. The design of the anchor foundation was extremely difficult because of geotechnical unit complex,ground anchors more,wide distribution,high positioning accuracy,mutual interference with other basement. The special problems in FAST anchor foundation had been studied one by one： the geotechnical units had been partitioned through engineering geological survey and mapping,main controlling factors in sites area,natural factors influencing geotechnical properties in sites area; accurate positioning of anchor center had been realized by setting up BIM after excavation and polar projection technology; mutual interference between devices had been adjusted and processed through polar projection technology. Research results had ensured the completion of FAST anchor foundation engineering successfully.