Analysis of Riverbed Deformation in Infrastructure Zones
Riverbed formation deformations usually proceed slowly.However during spring and autunn floods the processes are developed quickly.Erection of structures regulating flow in riverbeds or providing engineering services of other nature (dam,bridge passage,etc.) in a given section of the bed initiates artificially caused riverbed forming.They,indeed,are quicker than the previous but die very quickly.However regardless of causes stimulating riverbed forming,sometimes their consequences reach such large sizes,which threaten ecological conditions not only areas of the bed and its surrounding but also nearby residential and industrial areas.Therefore predictions of dangerous riverbed forming process and its final result assume great scientific and practical importance.This paper presents a physical model of riverbed deformation development caused at roads built over rivers and bridge passages erected for other engineering services which enabled to develop conceptions of mathematical description of phenomena related to the riverbed deformation.When a bridge passage is designing and constructing over a river the natural width of the riverbed is narrowing.As a result in that section the flow rate is developed and the stream begins washout process of the riverbed.With time the riverbed non-stable formation causes initiation of largest deformations decreasing the flow rate.In the section of a bridge passage the disturbed stability of the riverbed is recovered but in newly formed riverbed conditions.Hence,it can be assumed that transported by the river sih per route remains constant Qr =const.This concept of the silt balance maintaining is an important condition of the stabilized state.In evaluation of riverbed formation phenomena riverbed deformations final result is of primary importance.Until now the stabilized state was presented by a non-stable flow which was described by a system of non-linear differential equations.The latter are solved for various assumption conditions,limiting the obtained results application frameworks.A new approach for describing the problem is presented,according of which such a pattern of the newly formed stable riverbed is sought when the riverbed formation process runs as a stable one.Therefore the system of equations for a stable state presents a set of differential equations describing stable state.On the basis of the obtained results of their integration parameters of the shaped riverbed are determined and consequences of riverbed forming are evaluated.
river riverbed deformation river structure riverbed forming
P.H.Baljiyan A.A.Sarukhanyan
Yerevan State University of Architecture and Construction, 105/la Teryan Street,Yerevan, 0009, Republic of Armenia
国际会议
The 5th International Yellow River Forum (第五届黄河国际论坛)
郑州
英文
109-112
2012-09-24（万方平台首次上网日期，不代表论文的发表时间）