Experimental analysis for laying of flexible mattressesquasi-perpendicular to flow direction

• 1、National Inland Waterway Regulation Engineering Research Center, Chongqing Jiaotong University, Chongqing 400074, China
• 2、Chang Jiang Chongqing Waterway Engineering Bureau, Chongqing 400011, China

Abstract：The revetments, such as flexible mattresses, in the long-term riverbank and riverbed protection are commonly used. When in the larger velocity and water depth,however , the associated failure mechanisms of flexible mattresses, tearing and floating mattress are still not well understood yet. To enhance the fundamental understanding of the performance of flow among the pensile mattress at diffident direction placed, a laboratory experimental program was undertaken using high-resolution particle image velocimetry (PIV) to measure the 2-D velocity field of mimetic mattress, where transparent organic glass was used to represent the flexible mattress. The characteristics of water surface profiles, mean velocity profiles and turbulence intensity were analyzed, on the condition that geotextiles laying direction was quasi-perpendicular to the flow. The results indicated that slipping and tearing can easily occur for the beginning mattress and floating can easily occur for the middle mattress, when the upper surface respectively faced and was back to the flow. Besides, when the upper surface was parallel to the flow, it wasof the best advantage forthe sinking of flexible mattress. The results provided a theoretical basis for solving the sinking for flexible mattress in deep water.

Keywords： waterway regulation revetments flexible mattresses geotextiles laying flow characteristics