# 落石冲击力理论与数值模拟研究Research on the Theory and Numerical Simulation of Rockfall Impact Force

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The impact force of falling rock is one of the main loads to be considered in the design of tunnel structure. ANSYS/LS-DYNA numerical simulation was used to simulate the structure of concrete shed and cave impacted by falling rock. The numerical results were compared with the results of the existing theoretical calculation methods of rockfall impact. The results show that the recom-mended method for calculating rockfall impact force in China is seriously small, and the Japanese formula gives the largest result. The results of various theoretical calculation methods vary greatly. In order to ensure the partial safety design of the shed and cave structure, it is suggested to use the Japanese method to calculate the rockfall impact force.

1. 引言

2. 代表性的落石冲击力计算方法

2.1. 日本公式

Kawahara [2] 等基于Hertz弹性理论和落石冲击试验数据，给出最大冲击力公式为：

${F}_{\mathrm{max}}=2.108{\left(mg\right)}^{2/3}{\lambda }^{2/5}{H}^{3/5}$ (1)

2.2. 瑞士公式

Labiouse [3] 基于Hertz弹性理论和落石冲击试验数据，给出最大冲击力公式为：

${F}_{\mathrm{max}}=1.765×{M}_{E}^{2/5}×{R}^{1/5}×{\left(QH\right)}^{3/5}$ (2)

2.3. 隧道手册公式

《铁路工程设计技术手册–隧道》 [7] 给出了冲击力近似计算方法：

$F=\frac{Q{v}_{0}}{gt}$ (3)

2.4. 杨其新算法

$F=ma\text{\hspace{0.17em}}其中\text{\hspace{0.17em}}a=\frac{\sqrt{2gH}}{t},t=\frac{\left(0.097mg+2.21h+\frac{0.045}{H}+1.2\right)}{100}$ (4)

3. 二十六面体落石冲击棚洞结构数值模拟

3.1. 落石与棚洞材料参数

Figure 1. Structure model of shed

Figure 2. Rockfall model Figure 2Rock fall size

Table 1. The material parameters

3.2. 落石冲击棚洞结构的数值模型

Table 2. Concrete material model of HJC

Figure 3. The element model

3.3. 数值模拟结果与理论计算结果对比分析

Figure 4. The results of various theoretical algorithms are compared with those of numerical simulation

Table 3. The results of various theoretical algorithms are compared with those of numerical simulation

4. 结论

1) 由于日本公式的计算结果是最大的，因此在我国的工程实践中，对于棚洞结构设计时，出于偏安全的考虑，推荐使用日本公式计算落石的最大冲击力，并选取偏大的拉梅常数。

2) 现有落石冲击力计算方法都是基于实验结果的拟合公式，公式中的参数大多没有物理意义，因此导致各个公式计算结果相差千百倍，在今后的研究中，应该提出更为合理的力学模型，建立完善的冲击力理论体系。

3) 现有的落石冲击力计算方法都未考虑落石形状对冲击力的影响，在今后的冲击力理论计算方法研究中，应当考虑落石形状这一重要影响因素。

NOTES

*通讯作者。

 [1] Guangcheng, Z., Huiming, T., Xin, X., et al. (2015) Theoretical Study of Rockfall Impacts Based on Logistic Curves. International Journal of Rock Mechanics and Mining Sciences, 78, 133-143. https://doi.org/10.1016/j.ijrmms.2015.06.001 [2] Kawahara, S. and Muro, T. (2006) Effects of Dry Density and Thickness of Sandy Soil on Impact Response Due to Rockfall. Journal of Terramechanics, 43, 329-340. https://doi.org/10.1016/j.jterra.2005.05.009 [3] Montani, S., Descoeudres, F.O. and Labiouse, V. (1996) Ex-perimental Study of Rock Sheds Impacted by Rock Blocks. Structural Engineering International, 6, 171-175. https://doi.org/10.2749/101686696780495536 [4] Pichler, B., Hellmich, C. and Mang, H.A. (2005) Impact of Rocks onto Gravel Design and Evaluation of Experiments. International Journal of Impact Engineering, 31, 559-578. https://doi.org/10.1016/j.ijimpeng.2004.01.007 [5] 杨其新, 关宝树. 落石冲击力计算方法的试验研究[J]. 铁道学报, 1996(1): 101-106. [6] 中交第二公路勘察设计研究院有限公司. 公路隧道设计细则: JTG/T D70-2010 [S]. 北京: 人民交通出版社, 2010. [7] 铁道部第一勘测设计院. 铁路工程设计技术手册[M]. 北京: 中国铁道出版社, 1999. [8] 徐胜. 落石冲击力计算方法研究[D]: [硕士学位论文]. 重庆: 重庆交通大学, 2016. [9] Yan, P., Zhang, J., Fang, Q., et al. (2018) Numerical Simulation of the Effects of Falling Rock’s Shape and Impact Pose on Impact Force and Response of RC Slabs. Construction and Building Materials, 160, 497-504. https://doi.org/10.1016/j.conbuildmat.2017.11.087 [10] 黎良仆, 袁松, 谢凌志, 等. 落石冲击荷载作用下EPE垫层棚洞缓冲作用研究[J]. 四川建筑科学研究, 2016, 42(3): 46-49. [11] 中交第二公路勘察设计研究院. 公路隧道设计细则: JTG/TD70-2010 [S]. 北京: 人民交通出版社, 2010: 130-131. [12] 熊益波, 陈剑杰, 胡永乐, 王万鹏. 混凝土Johnson-Holmquist本构模型关键参数研究[J]. 工程力学, 2012(1): 121-127. [13] Bhatti, A.Q. and Kishi, N. (2010) Impact Response of RC Rock-Shed Girder with Sand Cushion under Falling Load. Nuclear Engineering and Design, 240, 2626-2632. https://doi.org/10.1016/j.nucengdes.2010.07.029