基于落石棚洞冲击试验的落石冲击力研究

基于落石棚洞冲击试验,考虑不同落石重量、高度和冲击角度对落石冲击力的影响,分析了落石冲击力在这三个因素影响下的变化规律,发现落石高度与棚洞顶板倾角共同变化时,随着落石高度的增加和棚洞顶板倾角的减小落石冲击力增大,增大幅度达80.02%;落石高度与重量共同变化时,当落石重量较小,落石冲击力随着落石高度增加后的变化幅度较小,反之较大,最大值较最小值的增大幅度达182.10%;棚洞顶板倾角和落石重量共同变化时,落石重量比棚洞顶板倾角对落石冲击力的影响大,增大幅度达48.99%。然后基于正交试验分析发现落石重量是影响落石冲击力最重要的因素,其次为落石高度,最后为棚洞顶板倾角。最后通过回归分析获得了棚洞落石冲击力计算公式,并通过方差分析证明了棚洞落石冲击力计算公式与各因素间的回归关系高度显著,因此该公式可用于落石棚洞设计时冲击力的计算。

Study on Impact Force of Rockfall Impact Experiment on Shed Tunnel

Rockfall shed tunnel is one of the effective measures for rockfall disaster prevention in the mountain area. Determination of rockfall impact force is the key point in rockfall shed tunnel design. The variation law of rockfall impact force under the impact of rockfall weight, height and impact angle was studied based on the impact experiment. It was found that the rockfall impact force increases when falling height increases and impact angle reduces, and the increment ratio is up to 80.02%. The variation amplitude of the impact force with falling height is smaller for light rockfall and is larger for heavy rockfall. The impact force grows by 182.10% from the minimum value to the maximum value. The influence of rockfall weight is obvious than that of impact angle on the impact force. The increase rate reaches 48.99%. It was concluded that the rockfall weight is the most important factor that affects the value of impact force, followed by rockfall height and impact angle sequentially. The impact force calculation formulas of rockfall on the shed tunnel were derived by regression analysis at the end of this paper. The regression relation between the impact force and influence factors was highly significant through variance analysis. So the calculation formula can be used in impact force calculation of rockfall shed tunnels.