Studies On Mornitoring Technology Of Mining Space Surrounding Rock Stress And Its Application

With the mining depth and intensity in our country increasing continuously, thedistribution and change of mining space surrounding rock stress are becoming moreand more complex. The phenomenon of coal and rock instability caused by miningsurrounding rock stress is on the rise. Studies on real-time monitoring technology ofmining surrounding rock stress will help deeply analyzing and revealing thedistribution and evolution law of mining surrounding rock stress, in the meantime,providing technical support for predicting and preventing rock burst and some othercoal and rock dynamic disasters accurately. Focusing on the coupling difficulties ofstressometer now available and coal and rock mass, this paper built the couplingmechanical model of stressometer and coal and rock mass surrounding the drill hole,revealed the coupling mechanical mechanism, and developed a mining stressmonitoring system which has good coupling with coal and rock mass. Combined withFLAC^3D and other technologies, this monitoring system was applied to study thespace-time distribution and evolution law of mining space surrounding rock stress.Based on all above, the warning technology and method of critical space mining stressgradient was raised, and has been proved and applied on the spot. The main studyresults as follows:(1) The coupling mechanical model of stressometer and coal and rock masssurrounding the drill hole was built, and the coupling mechanical mechanism wasrevealed, which providing technical support for ascertaining the initial stress of thestressometer,realizing the best coupling of stressometer and coal and rock mass.(2) Invented technology and method for mining stress monitoring, and thendeveloped the mining stress real-time monitoring system, included in which thestressometer could self-adaptively couple the coal and rock surrounding the drill hole,realtimely monitor the size and change of unidirectional, bidirectional andthree-directional coal and rock stress. And it can also connect the KJ system, realizethe synchronous real-time transmission,storage and processing with the monitoringinformation. This paper put forward one method that through combining a few ofstress inductive probes into one stressometer according to certain angle, it canmeasure and monitor the size and direction changes of two primary stresses in a planewhich take drill hole axis as the normal. (3) The real-time mining stress monitoring system was applied to monitor andstudy the dynamic pressure area stress of11061island mechanized working face withsoft coal in Linage coal mine. Combined the FLAC^3D numerical simulation software,electromagnetic radiation and monitoring technology of support resistance, thespace-time distribution and evolution law of mining space surrounding rock stress wasanalyzed synthetically. The results show that the mining stress of11061islandmechanized working face with soft coal is mainly on vertical direction, the influencescope and variable quantity are greater than those of horizontal. The width of pressurereleased zone ahead of coal wall is about6m, wider than that of general mechanizedworking face. The mining influenced distance is nearly120m, longer than that ofgeneral mechanized working face. Double stress peak value appears in dip directionfor the stress superposition in adjacent gobs. The low stress peak value appears6⁸maway from the roadway side wall, while the high stress peak value appearsapproximately17m away from the roadway side wall.(4) The warning technology of critical space mining stress gradient was raised.Indexes like mining stress,drilling volume,electromagnetic radiation and supportresistance included in this technology, and the demonstration and application havebeen conducted in11061working face. The results show that, under the sameconditions of coal and rock mass physical property,geological condition and stressstate, the degree and rate of strata behaviors like collapse and deformation of roadwayenlarged obviously, along with the enlargement of mining space stress gradient. Coaland rock dynamic disasters can be prevented efficiently through reducing miningspace stress gradient of coal and rock mass, releasing elastic energy accumulated bysurrounding rock mining stress changing timely.