|
|
|
PDF
|
|
Type:
|
Conference Paper |
|
Author:
|
Shan, Haoyin; Kerenyi, Kornel; Guo, Junke; Shen, Jerry; Wagner, Andreas; Xie, Zhaoding |
|
Conference:
|
6th International Conference on Scour and Erosion (ICSE-6) |
|
Location:
|
Paris |
|
Conf. Date:
|
Aug. 27-31 |
|
Date:
|
2012 |
|
URI:
|
https://hdl.handle.net/10535/8718
|
|
Sector:
|
Land Tenure & Use
Water Resource & Irrigation |
|
Region:
|
North America |
|
Subject(s):
|
erosion
soil
|
|
Abstract:
|
"Erosion in cohesive soils is challenging. It requires a better understanding of forces acting on soil clumps since cohesive soils entrain in a form of clumps. Unfortunately, such information is rarely available due to the slow development of sensors that are capable to capture these forces. An innovative direct force gauge (DFG) in an ex-situ scour testing device (ESTD) was developed to study forces acting on cohesive soil specimens, and to analyze the incipient erosion process. Similar to Couette flow, the ESTD uses a moving belt and a pump to propel the flow in a channel underneath the belt. The channel is 58 cm long, 12 cm wide and 2 cm deep. This well-controlled physical model mimics the near-bed flow of open channel reproducing hydrodynamic forces on cohesive bed soils. Specimens are mounted on a sensor disk that is servo controlled. The reaction forces of the servo controlled DFG equals to erosion forces acting on soil specimens. The pump and two cascaded filter cylinders enable clear flow conditions near soil specimens. When both belt and pump are operating a log-low velocity profile in the near boundary layer can be achieved. The erosion of artificial Kaolin clay specimens reveals the shear stress deceases with the erosion, while the vertical force is hard to predict because it depends on both weight loss of the specimen and the attenuation of the lift force. The mass loss after intermittent running can calculate the erosion rate of soil specimens. Two types of Kaolin are tested in the ESTD and the hole erosion test in the French Institute of Sciences and Technology for Transport, Development and Networks (IFSTTAR). Discrepancy between the critical shear stress exists and possible reasons are discussed."
|