摘要
围护体系的加固质量对基坑工程、基坑周边环境和地下管线的变形和稳定性具有重要影响。通过对基坑围护体系和周边环境进行实时、在线监测分析,可掌握基坑变形的发展动态,对基坑失稳破坏进行预警。分布式光纤传感技术与常规监测方法相比具有很大的优越性,如分布式、长距离、实时性和长期稳定性等,可满足基坑工程安全监测和基坑失稳早期预警的要求。本文对布里渊光时域反射计(BOTDR)的测量原理进行了介绍,设计了一套基于BOTDR的新型基坑工程分布式监测系统,详细阐述了工程应用中传感光纤的布设方法、光纤保护和温度补偿技术等。以实际工程为例,对基坑工程分布式变形监测结果进行了分析。监测结果表明,基于BOTDR技术的基坑分布式光纤监测系统能够准确地反映基坑工程的变形情况,具有显著的优越性,可用于基坑工程稳定性的监测和失稳预报。
Outer protective system are widely used in foundation pit, whose reinforcement quality has an important effect on the stability of foundation pit, surroundings around foundation pit. Real-time and on- line monitoring of outer protective system and surroundings around foundation pit will be useful for obtaining the deformation evolution and early-warning the foundation pit failure in time. In comparison with the routine monitoring method, distributed fiber optic sensing offers a number of attractive features, for example, distributed monitoring, long distance, real-time monitoring, long-term stability, and so on. So it fully meets the demand of the health monitoring of foundation pit and early-warning of foundation pit failure. In this paper, the measurement principle of Brillouin Optical Time-Domain Reflectometer （BOTDR） is in- troduced, and a novel distributed fiber optic sensor-based monitoring system for foundation pit engineering is introduced. The relative topics about application of BOTDR in foundation pit engineering are discussed in details, which include installation methods of optical fiber, optical fiber protection and temperature compensation method. Then taking a project as example, the authors analyzed the deformation monitoring data. The monitoring results show that BOTDR-based distributed monitoring system for foundation pit engineering can exactly reflect the states of deformation and has obvious advantages in terms of foundation pit deformation monitoring and real-time foundation pit failure prediction.
出处
《防灾减灾工程学报》
CSCD
2008年第2期184-191,共8页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家杰出青年科学基金项目(40225006)
国家自然科学基金项目(40572154)资助
关键词
围护体系
布里渊光时域反射计(BOTDR)
变形监测
分布式监测
outer protective system
Brillouin Optical Time-Domain Reflectometer（BOTDR）
deformation monitoring
distributed monitoring
