Sheet pile walls serve as retaining walls designed to hold back earth, water, or any other filling materials. Unlike masonry walls, these walls have a thinner section. Typically, they are utilized in a variety of applications such as constructing wharfs, quays, and piers located along water fronts. Additionally, they can be utilized in building diversion dams, like cofferdams, for river bank protection, and retaining the sides of cuts made in earth.
Various materials can be used to construct sheet pile walls, including timber, reinforced concrete, or steel.
Timber sheet piles have various applications, but they are primarily used for short spans and to withstand light lateral loads. Typically, they are employed for temporary structures such as braced sheeting in cuts. However, if timber sheet piles are to be used in permanent structures above water level, they must undergo preservative treatment. Despite this, their lifespan is still relatively short compared to other materials.
Tongue and grove joints are used to connect timber sheet piles to one another. However, they are not suitable for soils that contain stones because the stones may dislodge the joints. Therefore, it is important to consider the composition of the soil when selecting timber sheet piles for a project. If the soil contains stones, an alternative material may be more appropriate.
Fig. Timber sheet piles
Reinforced concrete sheet piles are prefabricated concrete components that usually feature tongue and groove joints. They are relatively heavy and bulky, and during driving, they displace significant volumes of soil. As a result, their driving resistance tends to increase. To address this, suitable reinforcement is provided, taking into account the significant driving stresses.
A typical section of an RCC sheet pile is depicted in the figure below. The large volume displacement of soil that occurs during driving necessitates careful consideration of reinforcement. Therefore, reinforced concrete sheet piles are an effective solution for projects where soil displacement is a concern.
Steel sheet piles are a popular choice for constructing retaining walls and other types of structures in civil engineering projects. One of the main advantages of steel sheet piles is their resistance to high driving stresses. This means they can withstand the force of being driven deep into the ground without deforming or breaking.
Another advantage of steel sheet piles is their relatively lightweight compared to other types of piles. This makes them easier to handle and transport, reducing the overall cost of construction. Additionally, steel sheet piles can be used multiple times, further increasing their cost-effectiveness.
Steel sheet piles are also versatile in their application, as they can be used both below and above water. They have a long lifespan and can withstand harsh environmental conditions. Furthermore, by providing suitable joints, it’s possible to create a continuous wall, increasing their structural integrity.
Steel sheet piles come in various shapes, with different cross-sectional configurations that are designed to suit specific project requirements. The pile length can be increased either by welding or bolting, making them adaptable to different soil and site conditions. Overall, these characteristics make steel sheet piles a highly desirable option for many engineering projects.
Fig. Straight sheet pile
Fig.: Shallow arch web sheet pile
Fig.: Arch web sheet pile
Fig.: Z-shaped sheet pile
Piles are commonly used in construction to resist bending moments. For larger bending moments, arch and Z-piles are preferred as they have a larger section modulus. However, for smaller bending moments, shallow arch piles with a smaller section modulus are used. This is because they are more economical and easier to install.
In cases where the web of the pile will be subjected to tension, such as in cellular cofferdams, straight web-piles are used. This is because they are better equipped to resist tension forces. By using the appropriate type of pile, the overall strength and stability of the structure can be maximized while minimizing costs and simplifying construction.