摘要
河道大规模采沙引起的溯源冲刷是一种剧烈的自然演变冲刷,会显著降低上游跨河桥梁的基础埋置深度,但我国相关规范中尚无关于桥下采沙坑溯源冲刷深度的简易计算方法。为提出一个可供实际工程使用的采沙河段桥下溯源冲刷深度计算公式,采用量纲分析方法分析桥下溯源冲刷深度的主要影响因素,建立桥下溯源冲刷深度计算公式的一般形式,并利用实验及实测数据确定公式待定系数。结果表明,桥下溯源冲刷深度主要受上游来流流速与床沙起动流速之比、水深与采沙坑深度之比、桥位至采沙坑距离与采沙坑深度的影响,桥下溯源冲刷深度随桥位至采沙坑距离增加按指数规律减小,建立的桥下溯源冲刷深度计算公式符合客观规律且与已有数据吻合较好。研究提出的溯源冲刷深度计算方法可为采沙河段桥梁基础埋置深度的设计与评估提供依据。
The retrogressive scouring caused by large-scale sand mining pits in rivers is a kind of severe natural evolution scouring,which can significantly reduce the buried depth of the foundation of upstream bridges.However,there is still no calculation method for quickly determining the retrogressive scour depth at bridges in sand mining rivers in the design codes of China.In order to put forward a formula that can be used in practical projects,the dimensional analysis method is adopted to analyze the major influencing factors of the retrogressive scour depth at bridges under the influence of downstream sand mining pits.The general form of the formula is obtained through the dimensional analysis,and the undetermined coefficient of the formula is determined using the experimental and measured data.Results show that the retrogressive scour depth at the bridge is mainly affected by the ratio of the flow velocity to the incipient velocity of bed sediments,the ratio of the water depth to the depth of the sand mining pit,the distance from the bridge site to the sand mining pit,and the depth of the sand mining pit.The retrogressive scour depth at the bridge decreases with the distance to the sand mining pit according to the exponential law.The proposed formula is in good agreement with the existing data and correctly represent the objective laws.It can provide a basis for the design and evaluation of the buried depth of the bridge foundation in sand mining rivers.
作者
陈启刚
赵恒
杨文杰
Chen Qigang;Zhao Heng;Yang Wenjie(Engineering Research Center of Railway Industry of Construction Technology for LongSpan Bridge in Special and Complex Environment,China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan,Hubei 430050,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《铁道技术标准（中英文）》
2023年第3期45-50,共6页
Railway Technical Standard(Chinese & English)
基金
青海省重点研发与转化计划科技成果转化专项项目(2021-SF-161)。
关键词
桥梁
基础埋深
采沙坑
溯源冲刷
计算方法
bridges
foundation buried depth
sand mining pits
retrogressive scour
calculation method
