DEEP EXCAVATION AND SHORING SYSTEMS
Diaphragm Walls
Diaphragm walls, also known as slurry walls, are a type of underground structure used in geotechnical engineering soil projects.
Diaphragm walls are applied to ensure the stability of deep excavation pits, retain the soil and additional loads, control surrounding settlements, and prevent heaving at the excavation base. Additionally, diaphragm walls are the optimal shoring system in areas with a high groundwater table as they provide necessary water impermeability.
Diaphragm walls are constructed by excavating a trench in the ground and supporting it with a slurry mixture to prevent collapse during the excavation.
The slurry, typically a mixture of bentonite clay and water, provides temporary support for the trench walls and prevents collapse during excavation. Once the trench reaches the desired depth, a steel reinforcement cage is placed into the slurry-filled trench, and concrete is poured according to the technique, forming a solid wall.
Diaphragm walls are commonly used in deep excavation projects such as basement construction for high-rise buildings, underground parking lots, metro tunnels, and other infrastructure projects.
One of the main advantages of diaphragm walls is their ability to withstand high lateral loads and provide a waterproof barrier, making them ideal for urban projects with limited space and high groundwater levels. They also offer excellent durability and can be constructed in varying depths and thicknesses to meet project requirements.
Overall, diaphragm walls are a versatile and reliable foundation shoring solution that plays a crucial role in the successful completion of complex construction projects.
Sheet Piles
Sheet piles are typically used to control unwanted water seepage in the soil, enhance soil stability, or create temporary walls. Sheet piles are usually made from steel and are flat, rectangular plates.
Due to their flexibility and lightweight nature compared to other structural elements, sheet piles can be used in various applications.
Sheet piles are typically installed using a crane or hydraulic pile driver. During installation, the plates are driven into the ground, and once the desired depth is reached, they are fixed in place.
Anchored Pile Wall
Bored pile walls are shoring systems used to ensure the stability of deep excavation pits, supported by horizontal elements such as prestressed ground anchors, soil nails, or steel pipe struts. These systems are constructed with spaced, tangent, or intersecting piles to maintain the stability of the excavation.
Soil Nails and Shotcrete
Soil nails are long, slender steel rods installed and secured into the ground or rock mass by drilling. Cement grout is injected into the drilled hole for reinforcement. Soil nailing is a passive anchoring application used to stabilize excavation surfaces or slopes.
Shotcrete is a type of sprayed concrete commonly used to encapsulate soil nails and stabilize excavated slopes. It serves as a protective layer that can be applied to sloped or vertical surfaces, with or without steel mesh reinforcement. Shotcrete effectively minimizes erosion and wear by eliminating air-soil interaction on the surface.
Ground and Rock Anchors
Ground anchors consist of a free zone, root zone, and anchor head. The drilling of anchor holes is carried out using appropriate anchor drilling machines, selected according to the soil type, to ensure the required size and angle as per the project.
The anchor cables are prepared according to project specifications before installation. The prepared anchor cable bundle is placed in the drilled hole, and the anchor head is installed after the anchor production is completed and prior to tension testing. Anchors are typically made of 7-strand, high-strength pre-stressed steel cables with diameters of 0.5 inches or 0.6 inches. A sufficient number of steel cables are placed in each anchor to safely bear the loads specified in the project. Centralizers ensure that the cables are positioned in the center of the hole, and in the root region where the anchor bears the load, the cables remain within the injection material.
