Calibration Of Erosion Testing Cylinder And Study Of Method For Cylinders Erosion Test

Scour is the number one cause of bridge failures, destruction of hydraulic structures and migration of the river bank. As a result, in a variety of soils it becomes necessary to predict and determine the rate at which scour takes place.But little is known about scour.In an attempt to assess this question,a large Erosion TestingCylinder(ETC) device has been developed by china institute of water resources and hydropower research.First,the device has some bugs which make it become impossible to conduct experiment of scour effectively;second,the large cylinder device is so unique that new design of experimental method for it is necessary.After a brief review of current knowledge on fundamentals of scour and the experimental method of previous erosion apparatus,improvement of large cylinder device is made,which includes adding a filter device and calibration of flow rate in the cylinder with flow probe.Secondly,design the method for estimating incipient motion of noncohesive soils and mensurating scour rate of soils.Then,calculate shear stress at soil-water interface for the cylinder device by using the Moody chart,adjust the calculation parameters by comparing the results of critical shear stress from cylinder device with Shields diagram at the same time.The result of cylinder device test indicates the improvement of large cylinder device and new method for erosion test are feasible.At last,the present paper deals with the diffierences between exponential erosion rate models and hyperbolic models by cylinder device erosion test.