Study On Failure Law And Support Technique Of Stratified And Weak Rock Roof Of Roadway

Most rock roof of roadway is sediment rock, so its intensity is low, the stratification is a common rock mass structure in coal mines. Stability of roof is basic condition about safe and high-efficiency produce. Resolve this problem or not, which is a key problem of deep mining and safety produce. So study on failure law and support technique of stratified and weak rock roof, and to logically design project about reinforcing roof ,which have very important theoretical signification and engineering application value. There are five structure styles in roof structure of roadways. The thesis discusses every geology characters and stability properties of roofs, and analyzes four basic styles about failure of weak rock roof in roadways. Using stratified roof of roadway, which was excavated in level or delay-slope coal bed, as study object, the failure mechanism of the single rock stratum is analyzed by the stability theory of plate, the study results have showed : the roof is flectional damage when the beam deflection inclines to infinity as the axial loads tend to critical load; the ratio between roadway's span and thickness is the most important factor of critical stress. Setting up models of numerical test, and carrying out the numerical tests for stratified rock roof in the condition of different thickness of stratum and different stress, to find out correlation failure law. Numerical tests indicate: the less thickness of stratum is, the more instability of the roof is; along with the horizontal stress growing, the damage of roof is increasing; The change of the horizontal stress affects more powerfully than the change of the vertical stress to the failure of the roof. On the basis of former people's study, according to the working mechanism of rock-bolting , this article gives out the methods of designing bolts' parameters about hang-condole action and bag-condole, as according to the different thickness of stratified rock roof, and it also gives out the principle of design. At last, a successful application of roadway supporting is given by the design method, which has proved that it is a simple and useful designing method.