Successful earthworks remediation requires a thorough geotechnical assessment to ensure stability, compaction, and long-term site integrity. Key considerations include:

• Soil characterization: Understanding soil gradation, permeability, and plasticity index to determine suitability for remediation.
• Load-bearing capacity: Ensuring remediated soils meet structural requirements for future land use.
• Settlement and consolidation analysis: Predicting how treated soils will behave over time, particularly for fine-grained or organic materials.
• Slope stability and erosion control: Evaluating shear strength and implementing geosynthetic reinforcements or bioengineering solutions where necessary.
• Water management: Addressing groundwater infiltration, capillary rise, and the impact of fluctuating water tables on remediated materials.

In-situ remediation and excavation/replacement each have advantages depending on site conditions and project goals:

• In-situ remediation (e.g., chemical oxidation, bioremediation, stabilization/solidification) minimizes material handling, reduces site disturbance, and can be more cost-effective for large-scale contamination. However, it requires precise monitoring to ensure uniform treatment and long-term stability.
• Excavation and replacement provide immediate removal of contaminated soils but can be expensive due to transportation and disposal costs. This method is often preferred when in-situ methods are ineffective due to contaminant type, soil composition, or hydrogeological constraints.
• Hybrid approaches, such as treating excavated soil on-site before reusing it, can optimize cost and environmental impact.

Innovative stabilization and solidification (S/S) techniques improve soil strength, reduce permeability, and immobilize contaminants. These include:

• Cementitious stabilization: Blending cement, fly ash, or slag with soils to improve bearing capacity and leach resistance.
• Pozzolanic reactions: Utilizing lime, silica fume, or other reactive materials to enhance long-term soil stability.
• Geopolymer-based solidification: Implementing alkali-activated binders that offer superior chemical resistance and reduced carbon footprint compared to Portland cement.
• Microbial-induced carbonate precipitation (MICP): A bioengineering technique that enhances soil strength through microbial activity, reducing erosion and permeability.
• In-situ vitrification: Applying extreme heat to fuse contaminated soil into a stable glass-like matrix, effectively immobilizing heavy metals and organic compounds.

Hydrology plays a critical role in remediation, influencing contaminant migration, erosion potential, and long-term soil behavior. Effective management strategies include:

• Groundwater control: Using cutoff walls, permeable reactive barriers, or dewatering techniques to prevent contaminant spread.
• Surface water management: Implementing engineered drainage solutions, such as bioswales, retention basins, and geotextile-lined channels, to prevent erosion and leaching.
• Capillary barrier systems: Designing multi-layered capping solutions to control upward moisture movement in remediated sites.
• Adaptive modeling: Utilizing hydrogeological modeling software (e.g., MODFLOW, FEFLOW) to simulate water flow and predict potential challenges before remediation begins.
• Eco-engineering solutions: Integrating phytoremediation with engineered wetlands to passively manage water quality while stabilizing soils.