某露天铁矿废弃排土场高134 m,基底为粉质黏土,平均厚度为12．65 m,基底坡度前缓后陡,后部坡度达16°。运用底面摩擦模型实验,研究基底在天然状态和饱水状态下的排土场边坡的变形破坏特征,并对排土场边坡潜在破坏的演化过程和诱因进行了探讨。基底天然状态下排土场边坡整体稳定,仅在下部边坡发生局部破坏。基底饱水排土场边坡沿粉质黏土层发生整体滑动。排土场的潜在破坏模式为滑塌—牵引—推移复合破坏模式,首先是排土场前缘一级边坡失效,沿基底粉质黏土层剪出；然后是边坡前缘侧向支撑力降低导致二级边坡临空面加大,潜在滑面逐渐扩展至二级边坡水平；最后是排土场边坡出现整体滑移,后缘张裂牵引排土场顶部,并沿张拉裂缝下挫至二级边坡,并继续推移下级边坡滑移,最终形成前部鼓胀后缘下挫的稳定状态。%A waste-dump in an Open-pit Iron Mine is with a height of 134 m. Its basis is on a silty clay layer with an av-erage thickness of 12. 65m,where slope gradient of the font area is slow but steep in the rear area;The maximum gradient in the rear area is 16°. A series of experiments on deformation and failure features of waste-dump slope with its basement in natu-ral and saturated state are conducted by the floor friction model. The evolution process of potential destruction and causes of de-stabilization are explored as well. The results show that the waste-dump slope with its basement in natural state is stable in whole,and only damaged in bottom. However,the waste-dump slope with its basement in saturated state slides down over the silty clay layer. The potential failure mode of the slope is a combination pattern of slump,tow and shove. Firstly,the first beach in the front of slope becomes unstable and shears over the silty clay layer. Secondly,the area of free face in the second beach increases since the lateral force is decreased. In the same time the slip surface develops from the first beach to the second one. Finally,the slope slides down in whole with the top area decreasing from the tension crack. Then the broken area shoves the top area to the second beach and the lower one. The slope ends up stable with bulging deformation in the front area and decreasing deformation in the rear area.
展开▼
