【摘要】 堰塞湖的溃决问题是研究堰塞湖的核心内容之一,也是堰塞湖进行排险和处置的重要依据。本文以唐家山堰塞湖为原型,设计室内1:250的近似模型实验,完成了堰塞湖自然溃决实验、梯形槽堰塞湖溃决实验、三角形槽堰塞湖溃决实验和复式槽堰塞湖溃决实验,通过对溃决过程中堰塞坝内部土体体积含水量变化特征、泄流槽侵蚀特征和溃决流量过程的分析,获得以下认识:(1)溃决初期以下切侵蚀为主、后期以侧蚀为主;溯源侵蚀方面,自然溃决表现最强烈,人工辅助溃决实验中溯源侵蚀由强到弱依次为:复式槽、三角形槽、梯形槽;(2)人工辅助溃决在一定程度上削减了洪峰流量,与自然溃决相比减小了7.7%～20.1%,表明开挖人工泄流槽降低坝前水位的措施对于降低堰塞湖溃决风险是可行的;(3)以溃决流量增长率高或到达溃决洪峰时间短为判定溃决初期排泄效率高的标准,对比3组人工槽溃决实验,排泄效率由高到低依次为:三角型横断面、复式横断面、梯形横断面。针对唐家山堰塞湖处置,可在梯形槽基础上开挖三角形槽变为复式槽来进一步提升溃决初期排泄效率。更多还原

【Abstract】 Dam-break of barrier-lakes is not only one of the key problems of barrier lake research but also an important topic of engineering research.Based on the Tangjiashan barrier lake induced by the Wenchuan earthquake,an indoor model test for barrier lake,with a scale of 1:250,was carried out,which included some dam-bursting tests without any artificial measures and others with different types of artificial cross-sections of the drainage channel,such as trapezoidal,triangle and compound section.After analyzing the results of the test,the characteristics of volumetric water content of the dam body,erosional features of drainage channels and the variation of bursting discharge,some conclusions are drawn as follows:(1)The dam-break pattern was primarily downward erosion in the early time and lateral erosion in the later time and the strongest intensity of headwater erosion occurred during natural dam-break test,followed by artificial dam-break tests with compound section,triangular section or trapezoidal section,respectively;(2) The discharge of artificial dam-break tests with longer duration was far smaller than natural dam-break test,the peak discharge of the former decreased by 7.7%~20.1%,indicating that the drainage channel was a good method of controlling water level in front of dam and feasible to reduce the risk of dam-break.(3) If a higher growth rate of discharge or a shorter time reaching peak discharge was taken as the standard of high drainage efficiency in the early time of dam-break,the drainage efficiency of triangular section,compound section,and trapezoidal section reduced sequentially.In terms of the experience of handling Tangjiashan barrier lake,a compound section channel is better than others.更多还原