以动态破坏时间鉴定煤的冲击倾向

To determine proneness of coal burst by dynamic failure time

一、引言我国煤矿发生冲击地压的条件极为复杂。从地质条件来看,除褐煤以外的各煤种,采深从200～1000m,地质构造从极简单至极复杂,各种厚度、各种倾角的煤层,顶板包括砂岩、灰岩、油母页岩等各种情况都记录到冲击现象;从生产条件来看,各种工艺和各种采煤方法都发生了冲击地压。同时,大量的冲击地压实例表明,同一矿井,

the hazard of impact pressure is not only due to tremendous enegy that coal solid releases when it fails under impact pressure, but also due to its instantaneous failure process. The duration of coal failure reflects its dynamic failure of energy acumulation and consumption. Therefore, the duration of dynamic failure of coal samples can be used to determine proneness of coal burst. Based on the tests of 1070 samples from 11 coal seams with different rock burst proneness in China and Poland, The failuee process of typical coal samples varies with its proneness.And after the ultimate strength is reached, the models of unstable fractures extension also vary. The dynamic time of failure follows the following criteria: DT≤50ms strong proneness 50<DT≤500ms medium proneness DT>500ms no proneness Comparing this index with those we used before, we can see that it reflects the entire process of energy trasition when coal is loaded by a loading system, and dynamic features of coal failure. It reflects the inherent proneness of coal. It is sensitive to impact pressure, so classification of its proneness can be made. This method is simple and can be tested and used easily.