Experimental Study On The Cause Of Water Damage In The Root Of The Xiaomi Spur Dike

Spur dike as the main channel regulation building,it can fetter the flow in channel,increase the depth of channel,protect the levees,but the spur dike will be damage in different degree under the water long time erosion.For the damaged of spur dike in the past,the main research was the groin head and the through dam,the study on the root of spur dike relatively few,but the damage of the root of spur dike some times happened in the upper reaches of the Yangtze River,researching on the damage of spur dike have great significance for protecting and optimizing the channel regulation structure.Based on the previous research methods and the corresponding theory,this paper relies on the river terrain of Xiaomi beach in the upper reaches of the Yangtze River and have done various flume experiments,including immovable bed experiments and movable bed experiments,The experiments use DCMS Velocity System to control the flow and use the Propeller Flow Velocity Meter which independently developed by Chongqing Jiaotong University to acquire velocity data.By flume experiments and combine with theoretical analysis,Study on the damage degree of different flow conditions and different riverbed terrain conditions,which Including the volume of washout,the formation and development of scour hole behind the root of groin,the water surface profile near the root of groin and speed of every section.And drawing the contrast diagram of washout volume under different conditions,the formation of scour hole behind the root of groin,the finally topographic map under the scour of water,the water surface profile and velocity distribution near the root of groin.In the detailed analysis of these and summarized the process and causes of washout and proposed the measures to protect it.Flow was the most influential factor of washout and the next was the length of spur dike,the water depth's influence only for 1cm to 3cm on groin crest.This paper revealed the whole process and critical condition of the damage of the spur dike and the velocity distribution near the root of groin by means of experiment for the first time.By changing the sizes of obstacle which in the upstream of opposite bank and the distances between the spur dike and it we can derivation formulas about best location of groin.