兴安矿深部软岩巷道大面积高冒落支护设计研究

STUDY ON SUPPORTING DESIGN FOR LARGE AREA SERIOUS ROOF CAVING OF DEEP SOFT ROCK ROADWAY IN XING′AN COAL MINE

普通小面积冒落支护技术已经被掌握,但是大面积高冒落很难被控制。兴安矿四水平重车线巷道破坏严重,发生大面积高冒落,冒落区长度为150 m,最大冒高为8.6 m,被称为“一线天”。通过对兴安矿四水平重车线高冒区支护现状进行现场调查和分析研究,发现其破坏原因主要有:(1)围岩强度低且层理发育;(2)原支护形式不合理;(3)水理作用;(4)巷道埋深大;(5)构造应力影响大。根据现场工程地质条件、岩石特性和破坏特点,通过室内试验,确定其软岩变形力学机制为高应力膨胀性软岩,并提出采用“双曲拱”柔层桁架支护技术进行支护,使巷道在空间上形成上下双硐室。工程应用效果表明,“双曲拱”柔层桁架支护技术是一种有效控制深部软岩巷道大面积高冒落的支护形式。

The support countermeasure of common small area roof caving has been studied and mastered, but the large area serious roof caving is difficult to be controlled, because the support method is very complicated and needs further study. By field investigation, the roadway of loaded-car line in Xing＇an Coal Mine was seriously destroyed. The length of roof fall is about 150 m and the maximum height of roof caving is 8.6 m. Supporting condition of serious roof fall in Xing＇an Coal Mine loaded-car line was investigated and studied by laboratory test and theoretical analysis. The cause of its failure was summarized as follows： （1） the intensity of wall rock is low; （2） original support is irrational; （3） water effect; （4） road way is deep; （5） structure stress effect. According to geological condition, rock character and destruction features, deformation mechanism of soft rock were ascertained as swell under high stress, and the supporting technology of double-arch flexible layer with rigid gap was put forward. The roadway is formed into double-chamber in space. Engineering effects indicate that doublearch flexible layer truss technique, as an effective method can be used to control the distortion of surrounding rock at the intersection successfully.