深基坑支护桩布里渊光时域分布式监测方法研究

摘要

Retaining pile is a key part of bracing and retaining structures which directly affect the stability of deep foundation pit. Therefore, it is important to monitor the strain and stress state of a retaining pile. In this paper, the single-ended detecting distributed optical fiber sensing technology based on the Brillouin Optical Time-Domain Reflectometer (BOTDR) was used for monitoring the deformation of a PHC type retaining pile in a deep foundation pit. The monitoring method was described and its effectiveness was well verified in a deep foundation pit in Nanjing. The results indicate that the BOTDR-based method is feasible to make a fully-distributed monitoring of the retaining pile in the deep foundation pit. It is expected to be a novel way for monitoring deep foundation pit.%支护桩是深基坑支护结构中的关键组成部分，其支护效果直接影响到深基坑的稳定性，因此对支护桩应力应变状态的监测十分重要。该文选择了一种能够单端测量的分布式光纤感测技术—布里渊光时域反射计（简称BOTDR），将其应用于深基坑支护桩的变形监测，介绍了这一技术的基本原理、需解决的关键问题及实施技术路线，并结合南京某深基坑工程，验证了这一技术方法的监测效果。结果表明，基于BOTDR的监测方法可以对深基坑支护桩进行全分布式监测，方法可行，结果准确，为深基坑支护桩监测提供了一种新的技术手段。