薄煤层开采软弱煤岩体巷道变形特征与稳定控制

针对百色矿区薄煤层开采条件下半煤岩巷道大变形及难控制等问题开展了一系列研究工作。首先,在巷道工程资料与数据的基础上,开展了薄煤层回采巷道工程地质特征的分析,发现薄煤层巷道围岩地质构造普遍较为复杂,岩体完整性差;现场监测了回采巷道围岩的变形全过程,分析了掘巷影响阶段、掘巷影响稳定阶段和工作面回采期阶段等时期的围岩工程行为及变形特征。然后,根据所收集的岩样和自制的煤岩组合体试样,分别进行了点载荷强度和不同高度比的煤岩组合体力学强度试验,结果表明,此类岩石力学强度较低,煤体与岩体破坏呈不均匀性。最后,在现有的理论基础上,分析了半煤岩巷道的滑移机制,推导了煤岩体层间滑移与巷道围岩失稳的本构方程,根据锚索的挤压承载和锚杆抗剪作用机理等阐明了软弱半煤岩巷道控制原理和支护要点,提出了以"顶板预应力长锚索+帮高刚度桁架锚索"为主体的"锚、网、索、梁"整体支护技术。支护试验表明:所提出的支护技术对于半煤岩巷道的控制效果较好,围岩变形在可控范围之内。

Deformation characteristics and stability control of soft coal rock mining roadway in thin coal seam

In order to overcome the problems of large deformation and difficult control of surrounding rock in semi coal rock roadway,the deformation mechanism and stability control were studied based on the thin coal seam in Baise Area.Firstly,on the basis of data collection and data sorting,the engineering geological characteristics of thin coal seam mining roadway were analyzed.It was found that the geological structure of thin coal seam mining roadway is generally complex and the integrity of surrounding rock is poor.During the whole process curve of surrounding rock deformation,the engineering behaviors and deformation characteristics of surrounding rock were analyzed in the initial roadway excavation influence stage,roadway excavation stability stage and working face recovery stage.Then,according to the collected rock samples and the self made coal rock combination samples,the mechanical strength experiments of coal rock combination with different point load strengths and different height ratios were carried out respectively.The experiments show that the rock with low mechanical strength,and the failure law of coal and rock mass is different,showing inhomogeneous deformation.Finally,the slip mechanism of semi coal rock roadway was analyzed,and the constitutive equations of interlayer slip and the instability of surrounding rock were derived.The control principle and supporting points of weak semi coal rock roadway were expounded according to the extrusion bearing of cable and the shear action of bolt.The overall support technology with anchor,net,cable and beam was proposed,which is mainly composed of roof pre stressed long cable and high rigidity truss cable.The support test proves that the proposed support technology has a good application effect in No.2406 roadway in Dongsun coal mine,and the deformation of surrounding rock can be restrained within a controllable range.