Strengthening canal-adjacent road infrastructure in Thailand with MIRAFI H2Rx 

Overview

The Royal Irrigation Department (RID) of Thailand is the primary government body responsible for managing water resources to support agriculture, domestic use, and sustainable development. Its responsibilities span constructing and maintaining irrigation systems, implementing flood control infrastructure, and developing water management technologies to serve both environmental and community needs. As part of this mandate, the department also supports road infrastructure, particularly in areas where access routes run parallel to canals or water bodies critical to Thailand’s irrigation systems.

This project focused on a local road situated along the Maharahj canal in Singburi Province. The canal is a branch of the major Chainat-Ayutthaya waterway, and both sides of the canal have roads that provide access to nearby rural areas. These access roads, however, were constructed using soil excavated from canal dredging activities, resulting in a subgrade with low shear strength. Additionally, the high groundwater table in proximity to the canal posed ongoing risks for pavement degradation and structural instability.

The project’s primary goal was to increase the pavement stiffness and reduce subgrade moisture to ensure long-term performance of the road while maintaining the structural integrity of the adjacent embankment. The RID design team sought a solution that could simultaneously manage the site’s geotechnical challenges and allow for rapid installation to meet the 150-day project timeline. Solmax partnered with the Royal Irrigation Department’s design engineer to deliver an advanced solution tailored to these conditions.

The successful completion of this road section brought multiple benefits: improved road durability for the client, better access and safety for local communities, reduced environmental impact through smart water management, and a more sustainable infrastructure design.

Challenge

The road’s location alongside the Maharahj canal introduced significant geotechnical and logistical challenges. The embankment supporting the road was vulnerable due to poor soil conditions. Originally formed by dredging soil from the canal itself, the subgrade lacked structural cohesion and had low bearing capacity. Combined with the presence of high groundwater levels, these factors significantly increased the risk of deformation and failure, especially under the dynamic loads introduced during construction.

One of the key risks was the potential collapse of the canal-side embankment due to increased loads from construction equipment and road materials. To mitigate this, the construction team was required to avoid operating heavy machinery near the canal edge. This constraint demanded a design and installation methodology that minimized loading on sensitive zones while maintaining speed and efficiency.

The installation began with excavating down to the subbase level, preparing the site for reinforcement. Following this, 27,000 m² of MIRAFI^® H2Rx was installed to provide reinforcement and moisture control. Crushed rock was placed over the geotextile as a base layer, and the final pavement surface was constructed on top.

Due to the geotechnical limitations of the embankment, constant monitoring was carried out during the installation process. The embankment’s profile was observed for signs of instability or movement, ensuring early detection and immediate mitigation if any failure indicators emerged.

Additionally, time was a constraint. With only 150 days allocated for the entire project, installation speed without compromising on performance was essential. This required a material solution that could be deployed efficiently and offer superior geotechnical benefits.

Solution

Solmax supplied MIRAFI H2Rx geotextile for the full 27,000 m² installation. The product was selected based on its dual-function capabilities, offering both reinforcement and moisture management tailored for soft soil and high groundwater environments.

MIRAFI H2Rx delivers enhanced moisture wicking, increasing the mechanical strength of the basecourse, which improves the road’s ability to distribute traffic loads over weak subgrades. This reinforcement mitigates rutting, reduces deformation, and improves long-term pavement performance. Additionally, the geotextile features internal suction properties, which help lower the equilibrium moisture content of the basecourse. This ability to control moisture further contributes to better compaction, increased load-bearing capacity, and resistance to moisture-induced failures.

One of the notable advantages of MIRAFI H2Rx in this application was the installation efficiency. Because the material is designed with the cross-machine direction (CMD) as the primary strength direction, it allowed for installation with the machine direction aligned longitudinally along the road. This contrasts with other geotextiles, which require installation perpendicular to the road alignment to maximize strength, often slowing the process. The result was a rapid deployment of 3 km of reinforced road in just five days – a significant time saving that contributed to staying on schedule.

No alternative products were considered due to the proven performance of MIRAFI H2Rx in similar conditions and the RID’s existing trust in the Solmax brand. The decision to use this material was also supported by Solmax’s technical services team, who provided guidance and support throughout installation to ensure compliance with best practices and to address site-specific conditions.

Throughout the construction, the project team adhered to strict safety protocols, especially regarding the canal-adjacent embankment. Heavy equipment was kept away from high-risk zones, and visual assessments of the embankment's profile were conducted routinely. These precautions, combined with the reinforcing action of the geotextile, prevented any structural failure of the embankment during or after construction.

In conclusion, the Royal Irrigation Department’s road stabilization project near the Maharahj canal demonstrates the effectiveness of integrating high-performance geosynthetics in complex infrastructure settings. MIRAFI H2Rx not only reinforced a weak subgrade and improved pavement performance but also enabled rapid, low-risk installation in a highly sensitive area.

The success of this project is attributed to three key factors: trust in Solmax’s brand and product performance, the significant time savings achieved through intelligent material selection, and the value-added technical support provided throughout the installation process. This collaboration between engineering design, material innovation, and field execution resulted in a durable, high-performance local road that serves both community and environmental resilience.