深海沉管隧道基础水下沉降监测技术

为消除管节间差异沉降,港珠澳大桥岛—隧过渡段沉管基础采用挤密砂桩+堆载预压的地基处理方式。详细介绍了采用液体压差式沉降仪监测沉管隧道基础沉降的应用技术,并获得了较好的复合地基沉降数据。采用多种技术手段保证仪器埋设成功率,包括作业时机选择、导线接头及导线保护等。对试验结果进行分析,结果表明该技术运行稳定性高、数据误码率低、不易受风浪及施工干扰,可实现对沉管基础的连续稳定无线监测。

An Underwater Settlement Monitoring Technique for Deep-sea Immersed Tunnel Foundation

The island-tunnel segment of Hong Kong-Zhuhai-Macau Bridge is featured with deep soft soil under the immersed tube foundation. Sand compaction pile together with preloading was adopted to eliminate the differential settlement between joint parts. In this paper,the technique of monitoring tube foundation settlement by liquid pres-sure settlement sensor is introduced in details. Satisfactory settlement data was obtained. A variety of technical ap-proaches,including the timing of operations,protection of wire connectors and wire,were employed to improve the success rate of equipment burying. Test results showed that the technique could perform continuous stable wireless monitoring as it is of high stability,low error rate,and is less susceptible to wind and waves and construction inter-ferences. Therefore it could realize the continuous and stable wireless monitoring of the foundation. The study is ex-pected to provide reference for the monitoring of composite foundation under deep water conditions.