基于重现期的落石尺寸设计值确定方法  

Method of Determining Design Value of Rockfall Block Size Based on the Return Period

作　　者：王玉锁[1] 吕宁宁 王明年[1] 唐建辉[1] 杨竣翔 赵状 肖鹏[1,2] 安博 WANG Yusuo;LYU Ningning;WANG Mingnian;TANG Jianhui;YANG Junxiang;ZHAO Zhuang;XIAO Peng;AN Bo(School of Civil Engineering,Southwest Jiaotong University,Chengdu 611756,China;College of Engineering,Tibet University,Xizang 850000,China)

机构地区：[1]西南交通大学土木工程学院,四川成都611756 [2]西藏大学工学院,西藏拉萨850000

出　　处：《西南交通大学学报》2025年第2期262-270,共9页Journal of Southwest Jiaotong University

基　　金：四川省自然科学基金项目(2022NSFSC1127);中国国家铁路集团有限公司科技研究开发计划重点课题(N2021G005);中央高校基本科研业务费专项(2682023CX075)资金资助.

摘　　要：山区交通落石事件频发且具有突发性和随机性,基于概率的防护结构可靠性设计是降低灾害风险的必要和有效手段,然而,作为设计基本参数的落石尺寸设计值的确定方法还不明确,使得可靠性设计不能有效进行.介绍基于泊松-广义帕累托分布(GPD)复合模型的落石尺寸-重现期预测方法,结合宝成铁路白—上段落石记录数据,进行GPD阈值选取,并分析记录中缺失的最大、最小落石尺寸对阈值选取和对预测结果的影响;与地震作用标准值超越概率对应,提出以“小落石不坏、中落石可修、大落石不塌”三水准设防为标准的落石尺寸设计值确定方法.研究表明:记录中缺失的最大落石尺寸对阈值选取影响小,但对落石尺寸预测结果影响大,与重现期对应的落石尺寸预测值随设定的最大落石尺寸呈指数型增大趋势,而记录的最小落石尺寸对阈值选取和预测结果的影响都较小;以宝成铁路白—上段落石记录数据为例,根据选取出的合理阈值,设定不同最大落石尺寸值,利用本文方法,预测得到宝成铁路白—上段50、100、1000、10000 a重现期落石尺寸区间范围,计算得到50、100 a设计基准期三水准设防标准对应的落石尺寸标准值即设计值,可为类似工程设计提供参考.The rockfall events on transport lines in mountainous areas occur frequently and are sudden and random.Probability-based reliability design of protective structures is a necessary and effective means to reduce the hazard risk.However,the method of determining the design value of rockfall size,as a basic parameter of the design,is still unclear,making the reliability design fail to be carried out effectively.The prediction method of rockfall size and the return period was introduced based on the Poisson-generalized Pareto distribution(GPD)composite model.According to the rockfall record data of the Bai-Upper section of Baoji-Chengdu Railway,the GPD threshold was selected,and the impact of the missing maximum and minimum rockfall sizes(vmax and vmin)in the record on the threshold selection and prediction results was analyzed.Corresponding to the exceedance probability of the standard value of earthquake action,a method of determining the design value of rockfall size was proposed,which was based on the three-level protection standard featuring“the structure doesn’t break under small rockfalls,can be repaired under medium rockfalls,and doesn’t collapse under large rockfalls”.The results show that the missing maximum rockfall size in the record has a small impact on the threshold selection but a large impact on the prediction results of the rockfall size.The prediction value of rockfall size corresponding to the return period increases exponentially with the set maximum rockfall size,while the recorded minimum rockfall size has less impact on both the threshold selection and the prediction results.By taking the record data of the Bai-Upper section of Baoji-Chengdu Railway as an example,according to the selected reasonable threshold,different maximum rockfall size values are set.By using the method presented in this paper,the interval range of rockfall size in return periods of 50,100,1000,and 10000 years on the Bai-Upper section of Baoji-Chengdu Railway is predicted,and the standard value(design value)of rock

关 键 词：防护结构 落石尺寸 重现期 广义帕累托分布 设计值 

分 类 号：U45[建筑科学—桥梁与隧道工程]