基于Rockfall数值模拟的边坡落石防护网修复加固方案研究∗

某水电站尾水支洞边坡多次发生落石灾害，原被动防护网已发生局部破损，严重威胁着尾水支洞施工期和运行期的安全，需对原防护网进行修复加固。由于山体陡峭、地貌复杂，人工调查无法确定落石源，采用高精度无人机航摄初步排查出四处可疑危险源区域，利用Rockfall 软件进行落石轨迹模拟计算，通过对比分析计算成果与观测到的落石落点位置与威胁区域分布情况，反分析确定了两处落石源。在此基础上，根据落石源的落石运动特征，复核分析了原防护能力不足的原因，发现原防护网的能级和高度不足是导致落石灾害发生的主要原因。通过提高防护网的能级和高度，提出了原位修复和增高加固两种方案。研究结果表明：两种方案均能有效减小落石威胁区域面积、降低落石率、改善运动特征参数。其中增高加固方案的防护效果更加显著，落石被全部拦截，落石弹跳高度和动能的最大值分别降低了69.64%、66.02%。对被动防护网破损部位的修复加固，综合考虑现场实际情况与落石模拟计算成果进行修复方案设计更为科学合理。研究成果可为该工程的落石防护方案提供科学依据，为类似工程设计与落石分析提供参考。

Study on Repair and Reinforcement Strategies for Rockfall Passive Protective Network Based on Rockfall Numerical Simulation

Rockfall disasters frequently occur in the tailrace branch tunnel slope of a hydropower sta-tion, leading to partial damage to the original passive protection network and posing severe risk to thesafety of the tunnel exit area during the construction and operation period. It is very urgent and neces-sary to repair and reinforce the original passive protection network. Given the steep and complex landform, the rockfall sources could not be identified through manual survey. Therefore, high-precisionUAV aerial imagery was utilized to preliminarily identify four potential hazard areas. Rockfall softwarewas used for trajectory simulation calculations. By comparing and analyzing the simulated results withthe observed rockfall landing positions and the distribution of the threatened areas, two rockfall sourc-es were identified through inverse analysis. Based on this, by analyzing the movement characteristicsof these sources, a review was conducted on the reasons behind the insufficient original protection ca-pacity. It was discovered that the primary causes for rockfall disasters were the low energy level and in-adequate height of the existing protection network. Two schemes were proposed to enhance the net-work''s energy level and height: in-situ repair and heightening reinforcement. The analysis results indi-cated that both schemes could effectively reduce the area threatened by rockfalls, lower the rockfall oc-currence rate, and improve movement characteristic parameters. Among them, the heightening rein-forcement scheme had a more significant protection effect, with all rockfalls being intercepted. Themaximum values of rockfall''s kinetic energy and bouncing height were reduced by 66.02% and69.64%, respectively. The scheme of in-situ repair and reinforcement of the network''s damaged sec-tions would be more logical and scientific when the actual site conditions and rockfall simulation resultswere taken into consideration. The research results provide a scientific basis for rockfall protection mea-sures of this project and serve as a reference for similar rockfall analysis and engineering design.