Multiple Bores-Holes that Help Your Structures

As we dive deep into the depths of civil engineering, bored pile foundations catch our attention as they sit in the soil and support the structure but then how does the soil help these foundation piles? To ensure that these foundations are laid down in the right area where the soil is healthy, a civil engineer performs boring in multiple areas, which is referred to as multiple bores.

 Types of Multiple Bores:

Displacement Boring: This type of boring is generally not suitable in the sand areas. It is carried out to understand the soil character through penetration resistance. Usually, 25mm to 75mm holes are made through displacement bore.

Wash Boring: Often carried out by the limited equipment, its inexpensive approach makes it one of the most sought-after ones by the vendors and contractors. A pipe—usually of 5cm diameter—is driven into the soil and then filled with water. When the pressure is applied, slurry soil comes out of the tube. Based on the color of the soil, its quality and type are ascertained.

Auger Boring: Ideal for soft to stiff soil types, Auger Boring is widely used for piling for both small and significant structures. The auger that’s equipped with the steel casing will rotate to collect the soil. Compared to other types, auger boring is efficient and saves time.

Rotary Drilling: As the name suggests, in rotary drilling, a sharp machine is drilled into the soil that even cleaves through the rock. The broken hard soil or rocks are then removed for examination. It is suitable when the designed hole diameter is not exceeding 20cm. It is the robust and conventional method of bore drilling, although it’s often expensive.

Percussion Drilling: When auger boring and water boring don’t work due to hard soil and the presence of rocks, percussion drilling comes to the forefront as a rescue. Percussion drilling is a manual process wherein the hammer is attached to the rope that will be descendent into the soil through the temporary casing with the help of a tripod. Since the stick is at cutting end, it will easily break through the stones and can reach depths of several hundred feet. Earlier, China-based engineers reached a whopping 4000 feet through multiple bores.

Benefits of Multiple Bores:

  • Stable structures that can have strong foundations
  • Less economical as foundation repairs would not crop up in the future
  • Can get the holistic view of the subsurface soil type
  • Extensive excavations can be significantly minimized
  • Engineers can construct Caissons of high capacity seamlessly  by expanding the base of the soil
  • Piles can be extended beyond and below the seasonal moisture variation
  • Minimal or zero disruption to the surrounding soil

 

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