A retaining wall is a solid structure, built to support and hold a mass of soil at different levels. There are various materials used to create retaining walls: concrete (blocks or liquid), treated woods, and boulders to help keep the soil to a slope. It is most often used in areas where there is an undesirable slope or in landscaping requiring severe shaping and modification for specific purposes (such as a road overpass or hillside farming).
While there are different types of retaining walls, keep in mind that each serves the same purpose: To retain the soil and prevent it from eroding. Here are the various retaining wall options:
- Gravity – It has a batter setback to resist pressure and improve the stability of soil behind the wall.
- Cantilevered – Often made of cast-in place concrete, reinforced stem steel, or mortared masonry, cantilevered retaining walls are buttressed on the front to help boost structural strength while holding or resisting high loads or pressure.
- Sheet Piling – The materials often used in building sheet pile retaining walls are steel, vinyl, or wooden plank. Its main purpose is to hold soft in tight places.
- Bored Pile – A series of bored pile are put together for excavation and construction purposes.
Why Retaining Walls Fail: Prevention
No matter how durable the materials in a retaining wall, it can fail over time if it is not cared for. Some of the common signs of retaining wall failure are leaning, cracking, and bulging of the structure. While damaged retaining walls can be rehabilitated, it is extremely important to identify what is causing weakness.
Poor Drainage – One of the most common causes for the failure of a retaining wall is poor drainage. Constructing a retaining wall in an area where the drainage system is poor is never advised because bad drainage causes increased hydrostatic pressure behind the wall.
An effective solution for this problem is to ensure that there is proper drainage in the area where you will have the retaining wall erected. A good drainage system can prevent premature deterioration of the structure by moving away excess water that can affect the foundation of the wall.
Improper Reinforcement – In the event where early signs of failure (such as cracks and deflections) begin to show, contact a paving and construction expert to examine the reinforcement depth, size, and spacing.
Design Flaws – Problems in retaining wall design often occur when the owner allows his/her budget get in the way of choosing a reliable retaining wall builder. Although you may think that choosing cheaper construction services might save money, you may pay more in the rehabilitation of the wall.
A good way to prevent flaws in the design is to hire the services of a reliable retaining wall builder. You can do some research about contractors; make sure builders are properly licensed before signing a contract.
Poor Foundation – One of the most important factors in the success of a retaining wall is a sturdy foundation. Poor foundations are the main cause of retaining walls cracking or collapsing. A retaining wall with a shallow footing has less capacity to withstand the lateral pressure of the retained soil.
Make sure your contractor conducts a thorough site inspection and is knowledgeable about compressible soil, the water table, and backfill material before building any retaining wall.