立交桥桥台桩基托换基坑支护设计与监测
Design and monitoring of foundation pit support project for pile foundation underpinning of abutment of interchange bridges
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摘要: 以郑州市中州大道黄河路立交桥匝道F26号桥台桩基托换工程基坑支护为例,提出了一种明挖和暗挖相结合的施工方案,及采用土钉墙喷锚、钻孔灌注桩和内支撑相结合的复合支护结构。采用远程自动化监测和人工监测相结合的数据监测方式,对支护结构进行实时数据监测。支护效果表明:支护结构和施工方案合理,边坡和周边地表变形得到有效控制,包含暗挖通道在内的基坑周边地表最大沉降为12 mm,最大水平位移为13 mm,均小于规范中规定的控制值;在整个施工过程中,基坑周边及上部道路交通未受到较大影响;数据监测系统为安全施工提供了参考,使得整个工程顺利完成。Abstract: Based on the engineering case of the foundation pit support of No. F26 abutment pile foundation underpinning project on the ramp of Huanghe Road Interchange Bridge on Zhongzhou Avenue in Zhengzhou City, a construction scheme combining the cut and cover method with the underground excavation is put forward, and the composite support of soil-nailing wall shotcrete anchors, borehole grouting and internal bracings is employed. The real-time data monitoring of supporting structures is carried out by means of the remote automatic monitoring and the manual monitoring. The results show that the supporting structures and the construction scheme are reasonable, and the deformations of the slope and the surrounding ground are effectively controlled, and the maximum vertical displacement and the maximum horizontal displacement are 12 and 13 mm, respectively, which are less than the control values. During the whole construction process, the traffics around and above the foundation pit are not affected. The data monitoring system provides a reference for the safe construction and makes the whole project be successfully completed.