落石运动过程偏移与随机特性的试验研究

Research on the Offset and Random Characteristics of the Rockfall during the Falling Process by Field Tests

通过112块不同形状、不同质量的落石现场滚落试验,发现落石形状、质量和运动模式对落石偏移比有显著影响。落石越接近球形、质量越大、运动模式越单一,其偏移比越小,反之则会出现较大的偏移比和横向威胁范围;试验中绝大部分落石的偏移比大于0.1,但均在0.3以内。鉴于此,建议在实际落石防护工程设计中落石偏移比取0.3,以控制落石横向威胁范围;或依据落石灾害危险性评价结果和可接受风险水平确定落石偏移比的取值。通过9块试验条件近似的落石试验表明,落石运动过程充满随机性,在落石运动路径计算方法中应考虑落石运动过程随机特性的影响,这对于落石灾害威胁区域的划定和被动防治系统的布置非常重要。

By the field tests on the falling process of 112 rockfall with different shape and quality, it was found that the shape, quality and movement mode of rockfall had significant effects on rockfall offset ratio. The more spherical shape, the larger quality and the lack of changes in its movement mode, the rockfall had smaller offset ratio. Vice versa, the rockfall had large offset ratio and transverse falling range. In the tests, the offset ratios of most rockfall were more than 0.1, but all of them were below 0.3. In view of this, it is recommended that the offset ratio of rockfall should adopt 0.3 in the design of practical rockfall protection engineering in order to control the transverse falling range of rockfall. Alternatively, the offset ratio value can be determined based on the risk assessment results of rockfall disaster and the acceptable risk level. The tests of 9 rockfall under almost the same test conditions show that rockfall movement is full of randomness. The influence of the randomness on rockfall movement should be considered in trajectory calculation method for rockfall movement, which is of great importance to defining the falling range of rockfall disaster and designing the passive prevention system.