What is Pile Foundation? Common Types, Material, Application of Pile Foundation.

Time:2022-10-14From:sinorock View:

A Pile foundation is a kind of foundation form with high bearing capacity, a wide range of applications, and long history. With the improvement of production and the development of science and technology, the type, process, design theory, calculation method, and application range of pile foundations have been greatly developed and are widely used in high-rise buildings, ports, bridges, and other projects. Pile foundation has significantly improved the efficiency of housing construction and laid a relatively solid foundation for the quality of construction in the modern construction process.

What is Pile Foundation?

The buried depth is relatively shallow (generally not more than 5 meters), for a shallow foundation; foundation buried depth of more than 5 meters is called a deep foundation. The most widely used deep foundation is the pile foundation.

A pile foundation, a type of deep foundation, is a thin column or long cylinder composed of concrete or steel used to support the structure and transfer the load at the necessary depth by end bearing or skin friction.

Common Applications of Pile Foundation

l High and heavy buildings whose natural foundation-bearing capacity and deformation cannot meet the requirements.

l Buildings where the natural foundation bearing capacity basically meets the requirements, but the settlement is too large and the pile foundation needs to be used to reduce settlement, such as multi-story residential buildings on soft ground; or buildings with strict restrictions on settlement.

l Heavy industrial plants and buildings with large loads, such as warehouses, silos, etc.

l Large precision instrument manufacturing such as buildings with very high requirements for building stability. For these buildings, a pile foundation is the best method to minimize ground vibration.

l All kinds of permanent buildings on soft and weak foundations or certain specialty soils.

pile foundation applications

Classifications of Piles

Common Types

l Friction Pile

It can be divided into pressure piles and tension piles and is used in geological situations where there is no hard bearing layer in the ground or the bearing layer is deep.

l End Bearing Piles

The foundation pile is placed on the bearing layer so that the pile cap can carry the superstructure.

pile foundation

According to the construction process, they can be divided into lei cement-soil piles, bored piles, and impact H-piles.

l Lei cement-soil pile

Lei cement-soil piles are driven into the ground by a piling machine. The advantages are material saving, high strength, and suitability for more demanding buildings. The disadvantages are high construction difficulty, long construction time limited by the number of machines, and not suitable for land made by pond filling/reclamation.

l Bored pile

Firstly, holes are drilled on the construction site, and when the required depth is reached, the reinforcement is put in and concrete is poured. The advantage is that the construction difficulty is low, especially for hand-dug piles, which can be free from the limitation of the number of machines and save time greatly. The disadvantage is that the bearing capacity is low and it costs materials.

l Impact H-piles (driven piles)

Impact H-piles are generally used in lands with shallow bedrock.

Classification by pile diameter

(1) Small piles: d≤250 mm

(2) Medium diameter piles: 250 mm<d<800 mm.

(3) Large diameter piles: d≥800 mm.

types of pile foundation

Specialty Piles

1. Jet Grouting Piles

2. Micropile

Micropile, also called mini-piles, pin-piles, or root piles, is a high-performance and high-capacity deep foundation drilling materials. Micropile is a type of grouted pile that uses a drilling and pressure grouting construction process.

3. Sheet Pile

Sheet pile, also known as steel sheet pile or sheet piling. The advantages of sheet piles are: high strength, easy to penetrate into the hard soil layer; can be constructed in deep water, and become a cofferdam with inclined support if necessary. Good waterproof performance; can form various shapes of cofferdam as needed and can be reused many times

4. Soldier Piles

Soldier piles are also known as Berlin walls or king piles. Generally used for foundation pit support, slope support and landslide management, bearing horizontal earth pressure or landslide thrust, generally need higher reinforcement than foundation piles bearing vertical force.

Materials

1. Timber piles

2. Steel Piles, Pipe piles

3. Prestressed concrete piles

4. Composite piles

A "composite pile" is a pile made of steel and concrete members that are fastened together, end to end, to form a single pile

Pile Foundation Design Details

1. Choose the right pile foundation

The reasonable choice of pile foundation form has a great influence on the safety, function, and cost of high-rise buildings. The choice of pile foundation form should consider the following aspects.

(1) Geological conditions.

(2) The physical and structural characteristics of the building.

(3) The way of using underground space for building functions.

2. The reasonable choice of bearing layer and pile length

(1) Provide a large enough single pile bearing capacity.

(2) To ensure that the building does not produce an excessive settlement.

(3) Considering the cost of pile foundation.

(4) Consider the possibility of pile construction technology.

3. Reasonable arrangement of piles

In the case of the same number of piles, the bearing capacity and the role played by the pile foundation are not the same under different ways of pile arrangement.

4. The horizontal bearing capacity of the pile foundation

The horizontal shear force and overturning moment of the base of high-rise buildings are mainly caused by earthquakes and wind. The horizontal shear force of the foundation caused by earthquakes generally does not exceed 5% of the total weight of the high-rise building. Because the center of gravity of the superstructure of the high-rise building is much higher than that of the foundation bottom, it also causes great overturning moments. These effects must be considered in the earthquake area. In coastal areas, due to the intrusion of ocean storms, the impact of wind may be even greater than that of earthquakes. For super high-rise buildings, the wind-induced horizontal shear and overturning moment of the base may be close to or even far exceed the results caused by the earthquake. Therefore, the pile foundation of a high-rise building must have enough ability to resist horizontal load and overturning moments.

5. The impact of pile foundation construction and use on the surrounding environment

Technical and economic rationality must be considered.

Summary

Sinorock has been specializing in the manufacture of geotechnical anchoring materials for more than 10 years, and our self-drilling anchor system has been widely used in foundation engineering, underground tunnel construction and other projects. If you have any other questions about geotechnical anchoring, please feel free to contact us.