考虑桥墩作用黏性泥石流淤埋特征试验研究  

Experimental Study on Silting Characteristics of Viscous Debris Flow Considering Pier Action

作　　者：刘志锋 谢涛[1] 陈欢欢 LIU Zhi-feng;XIE Tao;CHEN Huan-huan(College of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]重庆交通大学河海学院,重庆400074

出　　处：《科学技术与工程》2023年第1期77-84,共8页Science Technology and Engineering

基　　金：国家自然科学基金(41807272);第二次青藏高原综合科学考察项目(2019QZKK0902);重庆市研究生联合培养基地建设项目(JDLHPYJD2018001)。

摘　　要：淤埋是泥石流破坏桥墩的主要方式之一,是影响桥墩安全的关键因素。为研究泥石流体容重、沟床坡度、黏性颗粒含量3个因素对桥墩影响下的黏性泥石流淤埋特征,通过水槽试验的方法研究了不同泥石流体容重、不同黏性颗粒含量、不同沟床坡度对泥石流流速和淤埋泥深的影响。对泥石流运动形态、淤埋过程和淤埋特征进行分析,结果表明:黏性泥石流在桥墩作用下随着泥石流容重的增加依次呈现出飞溅型、爬高型、平缓型3种运动形态,淤埋泥深随时间呈“先增大,后减小,最后稳定”的变化规律;泥石流黏性含量、容重与流速呈反比关系,流速与坡度呈正比关系,黏性泥石流容重的增加对泥石流动力的影响弱于对黏度的影响;黏性泥石流容重较低时,泥石流黏度对流速变化的影响弱于坡度对流速变化的影响,黏性泥石流容重较高时,泥石流黏度对流速变化的影响强于坡度对流速变化的影响;坡度较低时,高容重泥石流对坡度改变更敏感,坡度较高时,低容重泥石流对坡度改变更敏感;泥石流黏性含量、容重与淤埋泥深呈反比关系,淤埋泥深与坡度呈正比关系;泥石流流速与淤埋泥深为开口向下的二次函数关系,通过拟合得到二者之间的函数关系式,为估算桥墩影响下的泥石流流速提供科学依据。Siltation is one of the main ways that debris flow destroys bridge pier,and it is the key factor that affects the safety of bridge pier.In order to study the siltation characteristics of viscous debris flow under the influence of debris flow bulk density,gully slope and viscous particle content on bridge pier,the flume test was conducted to study the effects of different debris flow bulk density,different viscous particle content and gully slope on debris flow velocity and mud depth.The results show that under the action of bridge pier,the viscous debris flow presents three motion patterns of splashing,climbing and gentle with the increase of debris flow bulk density,and the depth of buried mud increases with time,then decreases,and finally becomes stable.The viscosity content and bulk density of debris flow are inversely related to flow velocity,and the flow velocity is positively related to slope.The increase of bulk density of viscous debris flow has a weaker effect on debris flow dynamics than viscosity.When the bulk density of viscous debris flow is low,the effect of debris flow viscosity on velocity change is weaker than that of slope,and when the bulk density of viscous debris flow is high,the effect of debris flow viscosity on velocity change is stronger than that of slope.When slope is low,debris flow with high bulk density is more sensitive to slope change,while when slope is high,debris flow with low bulk density is more sensitive to slope change.The viscosity content and bulk density of debris flow are inversely related to the depth of buried mud,and the depth of buried mud is positively related to slope.The relationship between debris flow velocity and buried mud depth is a quadratic function of downward opening,and the functional relationship between the two is obtained through fitting,which provides a scientific basis for estimating debris flow velocity under the influence of bridge pier.

关 键 词：黏性泥石流 桥墩 淤埋泥深 流速 

分 类 号：P642[天文地球—工程地质学]