分布式光纤技术在覆岩岩层运动监测中的应用

Field application of distributed fiber optic sensing on overlying strata movement

为监测上覆岩层运动,利用BOTDR分布式光纤传感技术,研究了上覆岩层随工作面开采变形破坏运动规律。结果表明:随工作面推进,采空区顶板岩层存在悬臂梁和砌体梁两种形态,呈现旋转沉降和平移下沉两种运动状态;开采初期,采空区中部顶板岩层首先断裂垮落,采空区未垮落的顶板岩层呈现裂纹发育的悬臂梁状态,旋转下沉运动;开采中期,悬臂梁岩块断裂为旋转下沉运动的砌体梁B关键块;开采后期,该岩块破断为平移下沉的砌体梁C关键块。覆岩破坏范围呈现由中央向两侧煤柱移动的规律。

This paper aims to explore the movement law behind overlying strata affected by coal mining.The exploration is obtained by performing optical fiber strain monitoring of overburden movement by employing BOTDR distributed optical fiber sensing technology and thereby identifying the movement law governing overlying strata with mining deformation and failure of working face.The results show that along with the advance of the working face come two forms of cantilever beam and masonry beam in the roof strata of goaf,showing two motion states of rotational settlement and translational settlement;the early stage sees the overlying strata breaking and collapsing in the center of the goaf,leaving the adjacent un-collapsed strata in the state of cantilever beam with crack development and in rotary subsidence movement;the middle stage witness the rock block of the cantilever beam breaking in such a way to be the key block B of the voussoir beam with rotary subsidence movement;the later stage sees the key block B breaking to form the key block C of the voussoir beam in translational subsidence;and the failure range of the overlying strata is underlain by gradual expansion from the goaf center to both sides coal pillars.