Box-Type Energy-Dissipating Mudflow Flume Design
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Solution Overview
Problem
Drainage channels with energy dissipation structures face challenges in designing optimal roughness coefficients due to differences in baseplate characteristics compared to smooth channels, leading to potential erosion or deposition issues from debris flows, which are not effectively addressed by existing methods.
Innovation Solution
A method for designing an energy dissipation structure section in drainage channels that considers slope, length, width, and stone diameter, using a formula to calculate the roughness coefficient and optimize the design, ensuring debris flow velocity is within safe limits, involving field surveys and model tests to determine optimal parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the roughness coefficient is increased to reduce debris flow velocity and prevent erosion, then the channel's erosion resistance improves, but debris flow deposition occurs which reduces flow capacity
Solution Approach 1:
The invention changes the roughness parameter by introducing an energy dissipation structure section with specific geometric parameters (length L, width b, stone diameter D) and material properties. The roughness coefficient n is calculated using a formula that incorporates these parameters along with channel slope J, allowing precise control of debris flow velocity to prevent both erosion and deposition
Solution Approach 2:
The invention applies local quality by creating a distinct energy dissipation structure section within the drainage channel with different properties from the smooth channel sections. This section has closed five sides with stones and an open top surface, creating localized roughness exactly where energy dissipation is needed, while other channel sections remain smooth to maintain flow capacity
2Ease of manufacture
If the roughness coefficient is determined based on material type for smooth channels, then the design process is simplified, but the design accuracy is insufficient for channels with energy dissipation structures
Solution Approach 1:
The invention transforms the roughness coefficient determination from a simple material-based lookup to a calculated parameter based on multiple geometric and physical parameters. The formula n = n0 * (1 + 0.035 * (b/L) * (D^0.5) * (J^0.25)) incorporates energy dissipation structure dimensions (b, L), stone diameter (D), and channel slope (J) to accurately reflect the actual roughness
Solution Approach 2:
The invention uses a composite approach by combining the smooth channel material (with roughness coefficient n0) with the stone-filled energy dissipation structure. The overall roughness coefficient n is computed as a composite value that reflects the interaction between the smooth channel base and the rough stone filling, rather than selecting a single material type
3Stability of the object's composition
If the debris flow velocity is reduced to prevent channel destruction, then the channel stability improves, but the velocity becomes too small causing debris flow deposition
Solution Approach 1:
The invention uses parameter changes to control debris flow velocity within an optimal range. By adjusting the energy dissipation structure parameters (length L, width b, stone diameter D) and channel slope J in the roughness coefficient formula, the velocity is reduced enough to prevent erosion but maintained above the deposition threshold
Solution Approach 2:
The invention implements feedback by using the calculated roughness coefficient to determine velocity, then comparing this velocity to erosion resistance velocity and deposition velocity thresholds. The design parameters are adjusted based on this feedback to achieve the optimal velocity range that prevents both erosion and deposition
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
This method effectively regulates debris flow velocity by adjusting the energy dissipation structure's dimensions, providing a simple and convenient approach to prevent abrasion and erosion, and is applicable to channels with slopes from 15% to 35% and debris flow densities from 16 kN/m3 to 22 kN/m3.
Implementation Method 1
the roughness coefficient is a key parameter in engineering studies... the increased roughness of the channel caused by the interactions between a debris flow and the stones used to fill the channel
Data Source
AI summary
A method of designing a box-type energy-dissipating section of a box-type energy-dissipating mudflow diversion flume. Firstly, the longitudinal gradient J of the flume and the roughness coefficient n 0 of a fully-lined flume bottom (1) are determined. Then, the parameters of the box-type energy-dissipating section are set, and related parameters are substituted into a formula for calculation, so that the overall roughness coefficient n of the flume is obtained. Further, the flow velocity of the mudflow is calculated by means of the Manning formula. Finally, the flow velocity of the mudflow is compared with the non-scouring and non-silting velocity allowed by the flume, and the design value of the box-type energy-dissipating section is obtained through final optimization. The method factors in the longitudinal gradient J of the flume, the length L of the box-type energy-dissipating section, the width b of the box-type energy-dissipating section, and the average diameter D of filler stones. With the method, the overall roughness coefficient n of the flume under different design conditions can be determined reasonably, so as to further implement the optimized design of the box-type energy-dissipating section of the box-type energy-dissipating mudflow flume. Further provided is an application of the method of designing a box-type energy-dissipating section of a box-type energy-dissipating mudflow flume.