基于布里渊光时域反射技术的断层稳定性监测试验

Monitoring Experiment on Fault Stability Based on BOTDR

针对断层稳定性问题,采用BOTDR分布式光纤感测技术对内蒙阿拉善地区贺兰山西麓断层进行了监测分析,研究了自然条件下断层内部应力的变化情况。研究结果表明:贺兰山西麓断层在观测周期内钻孔周围围岩整体发生拉伸变形;断层面附近岩层的应力状态易受断层活动的影响,根据分布式光纤的应变分布曲线能够精确划分出断层活动的影响范围在断层之上9m和之下8m;BOTDR分布式监测技术可以有效捕捉到自然条件下断层微弱活动所引起的应变变化,实现应变的动态实时监测。BOTDR监测技术为长期、精细化评价断层稳定性状态提供了十分可靠的监测手段。

Aiming at the problem of fault stability,this paper uses BOTDR distributed optical fiber sensing technology to monitor and analyze the fault in the western foot of Helan Mountain in Alashan area of Inner Mongolia,researching the change of internal stress of fault under natural conditions.The followings were showed by the results.The stress state of rock strata near fault surface is easily affected by fault activity,and the influence range of fault activity can be accurately divided according to the strain distribution curve of distributed optical fiber,which is 9 m above the fault and 8 m below it.The hanging wall is mainly subjected to tensile strain,while the footwall is mainly compressive strain.BOTDR distributed monitoring technology can effectively capture the strain changes caused by weak fault activity under natural conditions,realizing the real-time dynamic monitoring of strain.BOTDR monitoring technology provides a very reliable monitoring means for long-term and fine evaluation of fault stability.