Dike Breach Calculation Using Unit Discharge
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Solution Overview
Problem
Current methods for calculating dike breach development are limited by inaccurate empirical formulas and complex mathematical models that require difficult-to-measure parameters, lacking a comprehensive and accurate description of the breach development process.
Innovation Solution
A calculation method using discharge per unit width of the breach as a variable, establishing formulas for lateral widening and downcutting rates, suitable for the entire dike breaching process and applicable under different inflow conditions, based on the broad crested weir flow formula and erosion coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If empirical formulas based on data statistics are used to calculate breach development, then the calculation structure is simple and can be used to quickly evaluate the development process, but the accuracy is low and the calculation results are unstable due to limited and poor-quality measured data
Solution Approach 1:
The patent transforms the calculation approach by changing from empirical parameters (requiring extensive measured data) to physical mechanism parameters (erosion coefficient and critical shear stress) that can be determined from fundamental soil and flow properties. This parameter transformation enables accurate breach development calculation without relying on large datasets for regression analysis.
2Measurement precision
If mathematical models based on physical mechanism are used to calculate breach development, then the simulation of actual dike breaching process is more accurate, but the method is complicated to solve and contains parameters that are not easy to be measured in the field
Solution Approach 1:
The patent extracts the essential physical mechanism from complex mathematical models by focusing on the core relationship between flow shear stress and soil erosion. It isolates the key parameters (erosion coefficient and critical shear stress) that govern breach development, eliminating unnecessary complexity while preserving the physical accuracy of the simulation.
Solution Approach 2:
The patent introduces flow shear stress as an intermediary parameter that connects the easily measurable flow characteristics with the soil erosion process. This intermediary enables the calculation of breach development using readily available flow data without requiring direct measurement of difficult-to-obtain erosion parameters in the field.
3Measurement precision
If flow shear stress is used as the main variable to describe breach development, then the scour rate can be calculated, but the water depth is difficult to measure accurately due to drastic elevation changes and difficulty in distinguishing the water-sediment interface
Solution Approach 1:
The patent uses flow rate as an intermediary parameter that can be accurately measured without requiring direct water depth measurement. By establishing the relationship between flow rate and shear stress through channel geometry, it bypasses the measurement difficulty of water depth while still enabling accurate calculation of scour rate through the shear stress erosion relationship.
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 provides a physically significant, practical, and repeatable calculation of dike breach development, accurately describing the breach process with fewer required parameters and high consistency with measured data, suitable for various inflow conditions.
Implementation Method 1
the breach flow is calculated by using a broad crested weir flow formula
Implementation Method 2
Q=μB√2gh1.5 where Q is breach flow, μ is breach flow coefficient, B is width of water surface at the breach, h is water depth of the breach
Implementation Method 3
the scour width (rate) of soil is expressed by water shear stress, critical shear stress and erosion coefficient
Implementation Method 4
E=kdΔt(τ−τc) or Vz=kd(τ−τd); where E is scour depth, kd is erosion coefficient, Δt is time, τ is average shear stress of flow, τd is the critical shear stress, and Vz is scour rate
Data Source
AI summary
The invention provides a calculation method for dike breach development process, which relates to the field of flood disaster prevention. In this method, the influence of hydrodynamic on the development rate of the breach is considered, and the unit discharge of the breach is taken as the main parameter. The parameter expression between the hydrodynamic factors and the development process of the breach is established for both lateral widening and vertical downcutting. According to the invention, the whole development process of dike breach can be calculated with only a few parameters, and the main parameter unit discharge can be directly obtained by the discharge formula of broad crested weir. As the calculation incorporating as much physical mechanism as possible and simple calculation procedure, the method has high practicability, good repeatability and scientificity.