Cemented Rockfill Dam Segregation Control via Layered Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cemented material dams face issues with insufficient utilization of coarse aggregates due to severe aggregate segregation, leading to resource waste and compromised construction quality.
Innovation Solution
A method for cemented material dam construction involving whole-process quality control, which includes determining the optimal water-binder ratio, using image scanners to adjust rockfill particle size and distribution, and employing rolling compaction with nuclear moisture-density gauges to ensure proper density and bonding between layers, thereby optimizing the use of coarse aggregates and minimizing segregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If coarse aggregates with particle size greater than 150 mm are used in cemented material dam construction, then resource utilization is improved and dredged slag can be effectively recycled, but aggregate segregation becomes more severe leading to compromised construction quality
Solution Approach 1:
The dam body is divided into multiple construction layers with different aggregate size requirements. The lower layers (first and second cemented sand and gravel layers) use finer aggregates (≤150mm) while the middle layer (cemented rockfill layer) utilizes coarse rockfill aggregates (>150mm). This segmentation allows coarse aggregates to be used effectively in appropriate zones without causing overall segregation, as each layer is compacted and controlled independently.
Solution Approach 2:
Different zones of the dam body are assigned different aggregate specifications based on local requirements. The cemented rockfill layer in the middle portion is specifically designed to accommodate coarse dredged slag materials (55% >200mm), while the upper and lower cemented sand and gravel layers maintain finer aggregates for better bonding and reduced segregation. This local quality approach allows optimal resource utilization while maintaining construction quality in each specific zone.
2Ease of repair
If coarse rockfill aggregates are used to improve resource utilization, then dredged slag recycling is enhanced, but construction quality control becomes more difficult due to severe segregation
Solution Approach 1:
The aggregate segregation issue is addressed in advance through careful planning of the construction sequence and layer configuration. Before construction begins, the dam cross-section is designed with specific layers (first cemented sand and gravel layer, cemented rockfill layer, second cemented sand and gravel layer) that pre-determine where coarse aggregates will be placed. This preliminary action ensures that coarse dredged slag is directed to the appropriate cemented rockfill layer where it won't cause segregation, eliminating the quality control problem before it arises.
Solution Approach 2:
The construction process implements quality control feedback mechanisms including monitoring aggregate distribution in each layer, verifying compaction quality, and adjusting construction parameters based on observed segregation tendencies. The multi-layer structure provides natural feedback zones where quality can be assessed and corrected layer-by-layer, preventing cumulative segregation effects and maintaining construction quality despite using coarse aggregates.
3Loss of energy
If aggregate particle size is increased to utilize coarse materials, then resource waste is reduced, but maintaining dam strength becomes more difficult due to segregation
Solution Approach 1:
The dam structure employs a composite material approach with three distinct layers: cemented sand and gravel layers (≤150mm) providing strength and bonding, and a cemented rockfill layer (>150mm) utilizing coarse dredged slag for resource recycling. Each layer uses materials optimized for its specific function, creating a composite structure that achieves both strength requirements and resource utilization goals. The cement binding material unifies these different aggregate sizes, preventing segregation while maintaining overall dam strength.
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 allows for the effective utilization of coarse rockfill aggregates, improving the construction quality and strength of cemented material dams by ensuring accurate water-binder ratios, proper particle distribution, and enhanced bonding between layers, thus reducing resource waste and aggregate segregation.
Implementation Method 1
measuring the apparent density of the rolled surface by a nuclear moisture-density gauge
Implementation Method 2
inserting a Vicat apparatus into the first cemented sand and gravel layer to measure an initial setting time and a final setting time
Implementation Method 3
obtaining image information of the rockfill by an image scanner; according to the image information, statistically calculating and obtain a maximum particle size, a minimum particle size, an average particle size
Data Source
AI summary
A method for cemented material dam construction based on whole-process quality control includes: determining a water-binder ratio of a sand and gravel material through a simulation test; laying rockfill on the first cemented sand and gravel layer before the final setting time of the first cemented sand and gravel layer; adjusting the maximum particle size of the rockfill and the distance between the particles in the rockfill according to the design requirements; spraying a cement slurry on the rockfill to wrap all the particles in the rockfill and laying a second cemented sand and gravel layer before the initial setting time of the cement slurry; performing rolling compaction on the construction layer until the decline in the thickness of the construction layer and the apparent density of the rolled surface meet the design requirements; and completing the cemented material dam construction.