特高位远程危岩群破坏成因及稳定性评价——以滇东北乌峰山地区为例

特高位远程危岩崩塌具有突发性强、速度快、势能大、摧毁力强、冲击性大、影响范围广等特征. 滇东北地区镇雄县5处危岩位于乌峰山南缘斜坡地带, 地层近水平, 崩塌区地形坡度达70°以上. 崩塌区和危岩区基岩裸露面积为0.07 km², 坡脚与坡顶高差达222 m, 危岩体平均高差159 m, 落石水平最大位移216 m, 属典型特高位远程危岩群. 采用定性和定量方法, 结合内外部条件, 综合分析危岩的10项基本影响因子, 评价其稳定性. 5处危岩在不同工况下稳定性差, 破坏模式为倾倒式, 高速远程动力崩塌易产生碎屑流, 呈散态扇形高速冲击流动, 裸露区面积大, 生态环境脆弱, 亟待治理.

DAMAGE CAUSES AND STABILITY EVALUATION OF EXTREMELY HIGH REMOTE DANGEROUS ROCK GROUP: A Case Study of Wufeng Mountain Area in Northeast Yunnan

Extremely high remote dangerous rock collapse is characterized by suddenness, fast speed, great potential energy, severe destruction force, strong impact and wide influence range. Five dangerous rock blocks are located on the southern slope of Wufeng Mountain in Zhenxiong County, northeast Yunnan. The strata are near horizontal and the topographic slope of collapse area is above 70°. The bare area of bedrock is 0.07 km² in collapse and dangerous rock area, with the height difference of 222 m from slope toe to top, the average height difference of 159 m for dangerous rock mass, and the maximum horizontal displacement of rockfall of 216 m, belonging to typical extremely high remote dangerous rock group. The qualitative and quantitative methods are used to comprehensively analyze 10 basic influencing factors of dangerous rocks and evaluate the stability combined with internal and external conditions. The results show that the five dangerous rocks have poor stability with the toppling-type damage mode. The high-speed remote dynamic collapse easily generates debris flows, which impact and flow in high speed as scattered fans. The large bare area and fragile eco-environment are in urgent need of treatment.