Subgrade Water-Vapor-Heat Simulation for Polyurethane Grouting Insulation
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Solution Overview
Problem
Existing thermal insulation methods for subgrades in permafrost regions are inefficient, costly, and disruptive, failing to effectively manage frost heave and thaw settlement due to seasonal climate changes.
Innovation Solution
A grouting subgrade water-vapor-heat coupling simulation method and system that utilizes a double-layer polyurethane thermal insulation structure, simulating temperature and water distribution through a two-dimensional axisymmetric geometric model and partial differential equations to analyze the impact of polyurethane layers on temperature profiles and freeze-thaw cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active refrigeration methods (duct-ventilated subgrade, slab-ventilated subgrade, thermal probe subgrade) are used to reduce subgrade temperature, then the temperature control effect is improved, but the construction cost and disturbance to the subgrade increase significantly
Solution Approach 1:
The subgrade utilizes its own thermal properties and the natural cooling effect of permafrost to regulate temperature. The thermal insulation layer reflects solar radiation and the subgrade's inherent thermal capacity provides passive temperature control without requiring external refrigeration systems, thereby eliminating construction costs and disturbances associated with active refrigeration infrastructure.
Solution Approach 2:
The patent replaces mechanical active refrigeration systems (ducts, vents, thermal probes) with a passive thermal insulation system based on thermal physics principles. The thermal insulation layer uses material properties (thermal conductivity, reflectivity) to achieve temperature control through natural heat transfer mechanisms rather than mechanical intervention.
2Temperature
If high-reflectivity surface is applied to reduce solar radiation heat input, then daytime thermal insulation is improved, but nighttime cooling effect is lost
Solution Approach 1:
The thermal insulation layer is designed as a composite structure combining materials with different thermal properties: high-reflectivity materials for solar radiation blocking during daytime, and thermally insulating materials with low thermal conductivity for both day and night performance. This composite structure enables the system to adapt to different temporal thermal conditions simultaneously.
Solution Approach 2:
The thermal insulation layer's parameters (reflectivity, thermal conductivity, thickness) are optimized to achieve different functional requirements at different times. The reflectivity parameter maximizes solar radiation blocking during daytime, while the thermal conductivity parameter maintains insulation performance during nighttime, allowing the same structure to adapt to varying temporal conditions.
3Temperature
If thermal insulation materials (EPS, XPS) are paved on site to insulate heat, then thermal insulation effect is improved, but the paving process is time-consuming and interferes with traffic
Solution Approach 1:
The thermal insulation layer is pre-fabricated as an integrated component before being installed on the subgrade. This preliminary preparation allows for quality control and optimization during manufacturing, and the pre-assembled structure can be installed more efficiently on-site, reducing the time required compared to laying individual insulation boards while minimizing traffic interference.
Solution Approach 2:
The thermal insulation layer is merged with other subgrade components (base course, binding layer) into an integrated multi-layer structure. This consolidation eliminates the need for separate insulation board paving operations, as the insulation function is incorporated within the existing construction sequence, thereby reducing overall construction time and traffic disruption.
4Reliability
If double-layer polyurethane grouting thermal insulation structure is used, then thermal insulation performance and subgrade stability are improved, but the simulation complexity increases
Solution Approach 1:
The thermal insulation structure is segmented into multiple polyurethane grouting layers with different thicknesses and positions. This segmentation allows the complex multi-layer structure to be modeled as discrete, manageable components in the simulation, where each layer can be independently defined and analyzed. The segmentation principle helps simplify the simulation process by breaking down the complex structure into standardized elements.
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
Provides accurate simulation and analysis of temperature and water migration, enhancing thermal insulation and stability of subgrades in permafrost regions, improving durability and safety.
Implementation Method 1
a double-layer polyurethane grouting thermal insulation structure
Implementation Method 2
a partial differential equation of a subgrade water-vapor-heat coupling process
Implementation Method 3
subgrade water-vapor-heat coupling simulation
Data Source
AI summary
Provided are a grouting subgrade water-vapor-heat coupling simulation method and system, a device and a medium, including: constructing a subgrade water-vapor-heat coupling geometric model; acquiring a partial differential equation of a subgrade water-vapor-heat coupling process, and establishing a relationship between physical fields; setting a temperature and water boundary condition; performing mapping and free triangle mesh generation on the subgrade water-vapor-heat coupling geometric model to obtain a meshing model; selecting initial data, and performing a simulation solution on the meshing model to obtain a water-vapor-heat coupling simulation result; and analyzing the impact of a double-layer polyurethane grouting thermal insulation structure on a temperature distribution, a freeze-thaw cycle depth, and water migration of a subgrade.