冲击性顶板运动及其应力演化特征的3DEC 模拟研究

 采用三维离散元程序建立煤层综放开采模型，研究综放工作面推进过程中采场、采空区上覆顶板岩层的冲击性运动形式和分段性垮落形态，记录并且分析采场动态推进过程中，采动围岩中岩层块体垂直应力、水平应力的动态演化特征。研究结果表明，采空区基本顶的运动形式、来压周期、来压强度与直接顶的垮落厚度有关；支架后方的直接顶挤压成拱缓冲了基本顶的来压冲击强度，同时也改变了其来压步距。随着工作面向跟踪块体方向的推进，块体垂向应力、水平应力存在高低应力分区，并且不断地波动，岩层应力峰值位置随着岩层高度的增加稍向煤壁前方移动。

STUDY ON MOVEMENT AND STRESS EVOLUTIONARY PROCESS OF IMPACTED ROOF WITH 3DEC

The model of long wall top-coal caving is established with three-dimensional discrete element method (3DEC) to study the impact movements of stope，mined-out area and roof strata and the segmentation falling are formed in actual mining at comprehensive mining face. The vertical stress and horizontal stress evolutionary process of mining rockmass are recorded and analyzed during the course of the stope moving. The research results indicate that the movement forms，roof pressurization period and strength of main roof have relationship with the drop thickness of immediate roof in mined-out area；the pressure arch formed by immediate roof behind hydraulic power support can buffer the roof pressurization strength of main roof，and at the same time，the roof pressurization period is modified. The block vertical stress and horizontal stress present high and low area divisions，i. e. the stress concentration exists in tracking rock block and the stress concentration degree continually fluctuates with the working face closing up to the tracking rock block. With the height of rock stratum increasing，the peak stress moves to the front of coal face.