颗粒流冲击力研究现状及讨论∗

颗粒流包括滑坡、泥石流、碎屑流、雪崩等,通常对桥梁、公路、居民区具有较大危害。分析了颗粒流的运动过程及其侵蚀、堆积和爬高等特性;此外,对颗粒流冲击力计算模型及其野外观测结果进行阐述。结果表明:现有冲击力计算模型认为冲击力在结构全断面呈均匀分布,忽略了颗粒流的运动特性对冲击力的影响;大块石冲击力计算忽略了颗粒破碎和浆体垫层效应对冲击力的影响,造成巨大的计算误差;由于传统传感器的缺陷,现有野外观测结果也存在较大误差。对此本文提出野外观测需要通过引入或开发新式压力传感器以得到更准确的颗粒流冲击力大小及其分布形式,从而更精确的修正理论模型;理论计算模型研究工作需要考虑颗粒流浆体的垫层效应、流体与基底的相互作用及块石冲击破碎等对流体冲击力的影响,从而推导出更准确的冲击力计算模型,指导工程实际。

Research Status and Discussion on Granular Flow Impact Force

Granular flow movement such as landslide,debris flow and avalanche usually has tremen?dous harm. This review paper concludes the kinetic characteristics of the granular flow,including accu?mulation,run up and erosion. This review provides an overview of the impact computational modelsand the results of the field observations of granular flow. Consequently,we find some problems of theimpact computational models and the results of the field observations of granular flow. First,the con?clusion that impact is uniform distribution along the whole section is incomplete,and the existing com?putational models exclude kinetic characteristics of the granular flow. Besides,when calculating the impact of the boulder,the existing models exclude the cushioning effect of slurry as well as the graincrush of the boulder,which results in great errors. Due to the defects of traditional sensors,there ex?ists great deviations in the field observation data. As for the above problems,our review providessome useful suggestions. For instance,a new pressure sensor need to be introduced or created in thefield investigations,which can obtain the good value and distribution of impact in the whole section,then the theoretical models can be corrected more accurately. Meanwhile,correction factors on thecushioning effect of slurry as well as the crush of the boulders should be taken into consideration whencrating new impact computational models. Thus,the corrected new computational models will pro?vide a guidance for engineering design.