Earth-Rockfill Dam Ice Pressure Calculation for Single-Layer and Rafted Ice
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Solution Overview
Problem
Existing methods for calculating dynamic ice pressure on earth-rockfill dams under wave and wind loads fail to distinguish between single-layer and rafted ice, leading to low accuracy and limited applicability, particularly for structures with varying slope ratios and shapes.
Innovation Solution
A method that identifies the type of ice layer as single-layer or rafted ice using experimental parameters and wave measurements, employing distinct formulas for each type, incorporating dam slope coefficients and considering wave and wind loads to calculate dynamic ice pressure accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a unified calculation formula is used for all ice layers according to the Specification for Load Design of Hydraulic Structures (SL744-2016), then the calculation process is simple, but the calculation accuracy is low because single-layer ice and rafted ice are not distinguished
Solution Approach 1:
The patent divides the ice layer into two distinct types: single-layer ice and rafted ice. Different calculation formulas are provided for each type, with single-layer ice using one formula and rafted ice using another. This segmentation allows for more accurate calculations by accounting for the different mechanical properties and failure modes of each ice type, directly resolving the contradiction between simplicity and accuracy.
2Ease of operation
If the existing calculation formula is used, then the calculation method is easy to apply, but the applicability is poor because it is limited to vertical dam surfaces or other wide and elongated structures
Solution Approach 1:
The patent introduces dam slope-specific coefficients (dam slope shape coefficient m and dam slope gradient coefficient λ) that are tailored to different dam configurations. These coefficients allow the calculation formula to adapt to various dam slope geometries and structures, transforming a universally applicable but inaccurate formula into one that maintains both ease of operation and high adaptability to different dam types.
3Ease of manufacture
If the existing calculation formula is used, then the calculation is straightforward, but the reliability is insufficient for determining the strength of hydraulic structures under wave and wind loads
Solution Approach 1:
The patent modifies the calculation parameters by introducing type-specific coefficients (γ = 1 kN·s/m³ for single-layer ice, γ = 1.2 kN·s/m³ for rafted ice) and dam slope coefficients. These parameter changes account for the different mechanical behaviors of single-layer and rafted ice under wave and wind loads, significantly improving the reliability of structural strength determination while maintaining calculation simplicity through the structured formula approach.
Data Source
AI summary
Disclosed is a method for calculating dynamic ice pressure on an earth-rockfill dam under the action of wave and wind loads, including obtaining calculation parameters of an ice layer under a multi-year average winter temperature; arranging a wave measurement device in a water area in front of the earth-rockfill dam to collect winter wave parameters; calculating an extreme wave height that causes ice cracking according to the calculation parameters and the winter wave parameters; determining whether the ice layer generates a crack due to wave fluctuations; calculating a critical ice thickness that causes flexural failure of the ice layer with or without the crack, and comparing the critical ice thickness with an actual ice thickness measured over the water area to determine a type of ice layer, and calculating the dynamic ice pressure exerted by the ice layer on the earth-rockfill due to the action wave and wind loads.