Conduit Repair Riblet Structure for Sediment Flow
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Solution Overview
Problem
Existing conduit repair methods face challenges in maintaining high flow capacity and preventing the accumulation of sedimentary sand in conduits with flat bottoms, such as horseshoe-shaped and rectangular conduits, where solid matters tend to accumulate easily and are difficult to remove, and the use of inner face bars with high rigidity to resist injection pressure reduces the inner diameter of the conduit after repair.
Innovation Solution
The formation of a riblet shape along the water flow on the bottom surface of the conduit using inner face bars with a recessed shape in the width direction, which reduces frictional drag and prevents solid matter accumulation, while also increasing the strength against injection pressure and facilitating easy removal of accumulated materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inner face bars with high rigidity are used to resist injection pressure, then the strength against injection pressure is improved, but the inner diameter of the conduit after repair is reduced
Solution Approach 1:
The inner face bar is designed with a recessed shape in the width direction, creating local variations in thickness. The recessed portion has reduced thickness to maintain larger inner diameter in critical flow areas, while the protruding portions maintain sufficient thickness for structural strength. This local quality variation allows the inner face bar to provide adequate injection pressure resistance without excessively reducing the overall inner diameter of the conduit.
2Productivity
If continuous inner face bars are used in the conduit-longitudinal direction, then the flow capacity of the conduit is improved, but the total length of inner face bars increases resulting in difficulty in transportation or manufacturing
Solution Approach 1:
The inner face bar is designed with a recessed shape that divides the structure into distinct protruding portions and recessed portions. This segmentation allows the inner face bar to be manufactured and transported in manageable sections while still providing continuous coverage when installed. The recessed portions create natural break points that facilitate manufacturing and transportation, while the overall continuous structure maintains flow capacity.
3Reliability
If inner face bars are installed in conduits with flat bottom, then the repair coverage is improved, but accumulated water and air are mixed into the space between inner face bar and wall surface leading to unfilled portions
Solution Approach 1:
The recessed shape of the inner face bar creates local variations in the gap between the inner face bar and the conduit wall. The recessed portions create larger gaps that facilitate better flow of filling material, while the protruding portions provide structural support. This local quality variation in gap size helps prevent unfilled portions by ensuring adequate filling material flow paths, particularly in flat-bottomed conduits where water and air accumulation is problematic.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The riblet structure enhances the flow capacity and prevents solid matter accumulation on the conduit bottom, making it easier to remove accumulated materials, while maintaining high strength and reducing the need for notches in the reinforcement body, thus simplifying installation and reducing unfilled portions of the filling material.
Implementation Method 1
The formation of a riblet shape along the water flow on the bottom surface of the conduit using inner face bars with a recessed shape in the width direction, which reduces frictional drag
Data Source
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AI summary
A conduit repair structure in which solid objects are less likely to accumulate on a conduit bottom and that, even if solid objects accumulate on the conduit bottom, facilitates removal of the solid objects. A hollow frame-like reinforcement body laid substantially along a cross-sectional shape of a conduit (1) is constructed using a reinforcing member (2) having fixing parts (2p) arranged at predetermined intervals on the inner side of the conduit (2). Resin inner face bars (10) are attached to the inner side of the reinforcement body, and a curable filling material is placed in the space formed by the inner face bars (10) and a conduit inner wall (1a) to form a filling material layer(3).□A body section (10c) of each inner face bar (10) is formed recessed in its width direction. The recessed shape of the body sections (10c) forms riblets on the bottom of the conduit, and this reduces resistance to water flowing in the conduit. Even in conduits, such as a horseshoe-shaped conduit and a rectangular conduit (box culvert), having flat bottoms and in which objects flow at low speed, the structure allows the objects to flow easier.