How is the cement pile used as a support structure different from that used as a foundation pile?
The requirements of the force characteristics of the pile is different. The stress of the foundation pile is characterized by the decrease of the pile stress with the increase of the depth, so the pile foundation of the pile is also larger. The support pile is different, such as cantilever structure, the pile at both ends of the pile at both ends of the shear force and bending moment is small, the second half of the force, so the pile body force two small middle.
Holding layer and base. Foundation pile often choose a better soil as a pile end bearing layer. And in order to make the pile bottom and the holding layer to better integration, usually have the base requirements, that is, after the drill bit to reach the bottom of the pile, do not enhance the original spray mixing 30 ~ 60s, so that the pile end and soil have a good contact. Cement soil support pile is no such requirement.
Pile head. The quality of the pile head is very important for the base pile, often by re-stirring, increase the amount of cement and other means to increase its strength, and usually 0.3 ~ 0.5m poor quality of the pile head removed. Support pile in addition to the pile to set the crown beam, plus top support, the general no such requirements.
Pile form. The use of the function determines the support pile usually overlap with each other into a concrete wall, the surface of the pile in the form of wall-like, grille and block, the pile in addition to the form of these pile, but also the form of column-like pile. In addition, the foundation pile is usually in accordance with the different soil to take the length of the pile in combination with the form of pile, and the length of the support pile is usually the same, or sometimes on the small variable cross-section form.
Offset. Cement pile as a foundation pile usually forms a composite foundation with the soil between the piles, usually allowing the pile to have a deviation of 50 to 200 mm. When used as a support pile, especially as a water curtain, the pile is very easy to cause leakage after the leakage, so the requirements of the pile position is very strict, usually not less than 50mm.