巫山县望霞乡桐心村危岩体变形破坏机制分析

FAILURE MODE ANALYSIS OF DANGEROUS ROCKMASS SLOPE AT TONGXIN VILLAGE IN WUSHAN TOWN OF WANGXIA COUNTY

本文通过详细调查危岩体所处斜坡变形现象发现,斜坡下部有约1m厚煤层被开采,斜坡上有塌陷和岩体开裂两种变形现象,两种变形均在继续发展;且这两者均与煤层开采有较大关联。工程地质类比法认为采煤引起的沉陷-掀斜变形机制对地表变形起主导作用。采用UDEC数值模拟表明,煤层开采后,位移变形由下向上传递。地表沉陷量向临空面增加,水平位移量也向临空面增加。上部坡体变形受垂直裂隙控制,下部坡体变形受水平层面和煤层控制;整体形成沉陷-掀斜。计算变形曲线显示变形有两个阶段,突破式跳跃变形阶段和缓慢变形阶段;如果没有新的开采活动,随着时间的推移山体最终会自行稳定下来。临空面的孤立危岩体在斜坡系统平衡后仍有较大速率,其稳定性较差,建议对其进行清除。

A detailed surveying on the deformation of a large rockmass slope at Tongxin Village in Wushan Town of Wangxia county indicates the slope is unstable and danger. This paper presents the finding that a 1 m thick coal seam at the bottom of the slope was mined. The slope has two deformatiom phenomena： subsiding and rockmass cracking. The two phenomena continue to develop. They are closely related to the coal mining. Engineering geological comparison indicates that the subsiding and declining due to the coal mining are the main factor causing slope deforming. The UDEC was used to make the simulation of the slope deformation. The numerical results show that after the coal seam was mined, the displacement is transferred from the lower to the upper portions of the slope. The surface subsiding in the front is larger than other places, also is horizontal displacement. The deformation of the upper slope is controlled by the vertical joints, while the deformation of the lower slope is controlled by the horizontal bedding planes and the coal -mining seam. They in whole form the subsiding -declining deformation of the rock mass slope. The calculated deformation curves suggest that deformation has two phases： Sudden quick deformation and slower deformation. I If no new coal - mining activity is carried out, as the time goes on, the mountain slope itself will become stable. The isolated rock columniation in the front slope still has high movement speed after the slope system has balanced. It is instable and has to be trimmed.