Meikuang Anquan (Jun 2023)
Deformation mechanism of deep high stress semi coal rock roadway and cross-border high-strength support technology
Abstract
Aiming at the surrounding rock control problems of deep and high stress semi coal and rock roadway, such as long deformation duration, large deformation and damage and breakage of support components, taking N3702 transport roadway of Yuyang Coal Mine as the engineering background, the deformation and instability mechanism and control countermeasures of surrounding rock of semi coal and rock roadway are studied by means of field test, theoretical analysis, numerical simulation and engineering test. Through roadway ground pressure monitoring and loose damage range testing, the characteristics of ground pressure appearance of semi coal rock roadway were quantified, and it was revealed that the weak deformation resistance of shale on the roof of semi coal rock roadway, the shallow depth of anchor cable anchoring into hard siliceous limestone, the high stressenvironment where the roadway is located and its axis is nearly perpendicular to the maximum horizontal principal stress were the root causes of severe ground pressure appearance. Based on the arch forming form of the natural caving arch theory, the combined compression effect and suspension effect of the bolt composite beam theory and the suspension theory, the formation mechanism of the low level “apparent compression beam” structure and the high level “invisible compression arch” structure of the roof during the bolt and anchor cable support of the rectangular section roadway is expounded. Based on the analysis of the influence law of the location lithology of the anchorage section of the anchor cable, the length of the free section and the preload applied by the anchor tail on the bearing capacity of the beam-arch anchor structure, a cross-border high-strength support technical scheme with the anchor bolt and anchor cable as the main support components in the rectangular section semi coal rock roadway is proposed, and the field application is carried out. The practice results show that the technology effectively controls the continuous deformation of deep high stress semi coal rock roadway, and ensures the stability and safety of surrounding rock and support components.
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