Study And Application Of Piping Risk Assessment Of Embankment Foundation ——Taking The Embankments In The Middle And Lower Reaches Of The Yangtze River As An Example

Piping,which is extremely harmful to the safety of dikes,is one of the common dangers in dike engineering.Classification of piping risk is conducive to the quantitative analysis of the effect of various influencing factors on the regularity of piping.The classification according to the degree of danger is an important foundation of making policy classified for the piping risk.The result not only is an important way to improve the pertinence and scientific of the handling of piping risk,but also could improve the efficiency of emergency rescue.Based on macro risk assessment,from the perspective of emergency rescue,a risk assessment system and a risk assessment model for the risk assessment of dyke foundation pipe risk is established by collecting,sorting out,and screening evaluation indicators for the embankment surge of the middle and lower reaches of the Yangtze River.Then,the emergency response measures are logically analyzed according to the evaluation result and the characteristics of the dangerous situation.the piping emergency response plan is formulated,and the independent programming software,which could realize the real-time assessment of the risk level and the intelligent decision-making of the emergency response measures is worked out.The main research results are as follows:Firstly,based on the analysis of recently management cases for the risk of piping in dike foundation,combining with the development process of embankment piping,evaluation index system is set for embankment piping hazard from hydraulic factor,boundary condition etc.The index is quantified,then the evaluation standard is established.Secondly,according to the index system,a comprehensive evaluation model is constructed by using the analytic hierarchy process and the fuzzy comprehensive evaluation method.The factor sets,evaluation set,weight set and membership function are built for the evaluation target.Comprehensive evaluation results of piping hazard could obtain based on the principle of maximum subordination.Then,the piping emergency response measures are divided into three categories:engineering measures,emergency monitoring and non-engineering measures,which makes the emergency response methods for piping risk more comprehensive.counter measurement is put forward for the emergency monitoring measures,from different countermeasures are put forward for basic observation points and professional observation points,which could effectively deal with the occurrence and development for of the dangerous situation of piping surge in the embankment foundation.Based on the research on emergency response measures,combined with the results of the risk assessment of the embankment foundation piping risk and the characteristics of the danger situation,an emergency response plan for the embankment foundation piping risk danger situation was formulated.Finally,the risk assessment model and emergency disposal decision of embankment foundation piping risk are implemented systematically.It is designed as a GUI interface which is easy operation.And the feasibility of the system is verified through practical cases.By comparing evaluation results with those of the actual situation,it can be shown that the system are reasonable and credible,which could improve the rescue efficiency of piping risk to a certain extent,and avoid piping damage and embankment collapse.