1, piling principle:
Because if the ground building is to be built on the ground, the ground will bear a lot of pressure, and it is often difficult to ensure that the ground has enough strength to resist pressure.
Therefore, it is necessary to reinforce the foundation bearing the building or improve the bearing mode of the foundation, so I thought of piling on the foundation, so that most of the weight of the building can be transferred to a deep position below the ground through the pile, because the foundation at this position has much greater bearing capacity than the ground.
2, piling requirements:
The piling site shall be flat and solid, with no obstacles at high altitude, no holes in the ground, smooth roads and no accumulated water after rain, and a safety warning zone shall be designated to prevent irrelevant personnel from entering or leaving.
About how deep the pile should be driven, it depends on the distribution of underground strata (professionally called geological structure layer). If it can withstand the pressure of the building, the pile will be driven here. If not, then continue to deepen.
Piling method:
1, hammering method:
The impact energy of pile hammer is used to overcome the resistance of foundation soil to pile, and the pile is driven to a predetermined depth, which is suitable for soft plastic or plastic cohesive soil layer. The main equipment used is pile frame, pile hammer and power equipment. There are four common pile hammers: drop hammer, single-acting steam hammer, double-acting steam hammer and diesel hammer, which have the advantage of simple structure.
2, vibration method:
When piling, a high-power vibrating pile driver is installed at the top of the pile to reduce the resistance of foundation soil to the pile by vibration force. The piling efficiency in sandy soil is very high, and it can also be used for sinking and drawing steel sheet piles and steel pipe piles.
3, water injection method:
Also known as water jet pile sinking method, it is an auxiliary method of hammer method and vibration method. Using high-pressure water flow, the soil around the pile tip is loosened through the injection pipe installed at the side of the pile or in the hollow pile, so as to reduce the pile driving resistance. When the pile tip sinks to about 1 ~ 1.5 meters away from the design elevation, water injection shall be stopped.