Energy-Governed Multiscale Reinforcement of Foundation Soils Using Hybrid Nano-Silica and Nano-Polymers: Coupled Shear–Permeability–Thermal Mechanisms and Bounded Impacts on Built Environment Energy Efficiency

Abstract

Soil behavior beneath building foundations is commonly treated as static in energy performance assessments, despite its coupled mechanical, hydraulic, and thermal nature. This study develops an energy-governed multiscale framework to quantify how hybrid nano-silica and nano-polymer reinforcement of foundation soils influences energy efficiency in the built environment through coupled shear–permeability–thermal mechanisms. Laboratory-scale characterization is combined with constitutive modeling, numerical simulations, and foundation-scale energy balance analysis to establish a transparent causal chain from nano-engineered soil behavior to building energy demand. Results demonstrate that hybrid reinforcement produces synergistic stabilization of shear response and permeability, leading to moderated moisture-dependent thermal conductivity and reduced foundation heat losses. Time-series energy analysis and Pareto-based trade-off evaluation confirm that the resulting energy benefits are bounded yet measurable, supporting decision-oriented optimization rather than overgeneralized performance claims. The proposed framework positions soil reinforcement as a complementary energy management strategy that integrates geotechnical performance with building energy efficiency through quantitative, multiscale, and decision-focused analysis.