王琼 金永黎 欧元超 付茂如

摘 要：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。

关键词：贺兰山;断层稳定性;BOTDR;分布式监测;应变

中图分类号： P694文献标志码：A

文章编号：1672-1098（2021）02-0051-06

收稿日期：2020-05-18

基金项目：安徽理工大学研究生创新基金资助项目（2019CX1002）

作者简介：王琼（1997-），女，陕西宝鸡人，在读硕士，研究方向：地球探测与信息技术。

Monitoring Experiment on Fault Stability Based on BOTDR

WANG Qiong， JIN Yongli，OU Yuanchao，FU Maoru

（School of Earth and Environment， Anhui University of Science and Technology， Huainan Anhui232001， China）

Abstract：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.

Key words：Helan Mountain; fault stability; BOTDR; distributed monitoring; strain

斷层是地壳受力发生断裂，沿断裂面两侧岩块发生的显著相对位移的构造，在浅层地壳中发育广泛[1]。断层结构面不仅破坏了岩体的连续性、完整性，而且严重影响着断层带内岩体的物理力学特性，对地层稳定性有着极为不利的影响[2]。国内外学者针对该问题开展了大量研究工作，也取得了一定成果。文献[3]等通过对SanAndreas断层地应力变化的长期观测，得出断层附近一定范围内岩体所受最大剪切应力与其距断层的距离成反比。文献[4]利用断层的几何形态和三向主应力间的关系将断层划分为正断层、逆断层及走滑断层，并利用库伦准则计算出此类断层的摩擦系数。……