Paramesh Wall along Sarangani-Davao del Sur Coastal Road

In the mountainous interior of Sarangani Province, a narrow rural road winds along a steep hillside and connects several farming communities to the municipal center. For many years, this road has served as the primary route for transporting agricultural products such as corn, coconuts, and vegetables to nearby markets. However, residents have recently faced a serious problem: progressive road erosion caused by an unstable slope. The geography of Sarangani contributes significantly to this hazard, as the province consists of gently sloping coastal plains and mountainous uplands inland where many farming communities are situated. The region experiences abundant rainfall throughout the year under the Type IV Philippine climate, where precipitation is relatively evenly distributed with no pronounced dry season. Continuous rainfall saturates the soil and increases slope instability, particularly along road cuts and exposed hillsides. As a result, cracks have formed along the pavement, loose soil frequently washes onto the roadway, and portions of the road shoulder have collapsed, leaving only a narrow passage for vehicles. This condition disrupts transportation of crops, limits access for residents and schoolchildren, and raises concerns that continued rainfall could trigger a larger slope failure that may completely block the community’s only access road.

Due to the increasing risk posed by the unstable slope and the importance of the road to the local community, the project client sought the assistance of Maccaferri to evaluate the site conditions and determine the most suitable engineering solution. The objective was to identify an effective slope stabilization and erosion control system that would restore the safety of the roadway while ensuring long-term stability of the hillside under the area’s challenging soil and rainfall conditions.

To address the instability of the slope and the ongoing erosion affecting the roadway in Sarangani Province, a Mechanically Stabilized Earth (MSE) wall system was proposed as the main slope protection solution. This approach stabilizes the slope by reinforcing the soil mass while providing a durable facing to prevent further erosion and protect the road from collapse, particularly under the area’s heavy rainfall conditions.

The wall facing utilized the Terramesh System from Maccaferri, while Paragrid geogrids were installed as soil reinforcements to improve the stability of the reinforced earth structure. To address scouring at the toe of the wall caused by surface runoff, Reno Mattress Plus units were incorporated to provide erosion protection and prevent soil loss at the base of the structure. Together, these systems provide a stable and durable solution for protecting the slope and maintaining safe road access