RU2549632C1 - Construction method of pile-slab foundation of high-rise building - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: construction method of pile-slab foundation of high-rise building includes excavation of pits and piling field with subsequent concreting of foundation slab. Piling field is constructed over the entire area of the pit made of bored or driven piles of the same length, after that the jacks are installed on each pile of the central zone of pit and load of value equal to 0.8-1.0 of the estimated load is applied by turn on pile, followed by removal of load after conditional stabilisation of the pile settlement to equalise the stiffness coefficient between the piles of the central and peripheral zones of foundation slab.

EFFECT: increase of the load-carrying ability of the foundation under the high-rise building, reduction of labour coefficient of its construction and materials consumption.

1 ex, 2 dwg

Description

The invention relates to the field of construction, and in particular to the device of plate-pile foundations for high-rise buildings.

A known method of constructing a pile-slab foundation, including the device of a pit, pile field and concrete foundation slab. To increase the bearing capacity of the foundation, the inter-pile space is compacted by injection of a hardening solution into the soil / 1 /.

The closest is the method of constructing a pile-slab foundation, including the construction of a pit, pile field and concreting of a foundation slab. The construction of piles is carried out by immersing the central piles to the calculated depth, and the peripheral ones are higher in accordance with the relief of the pit / 2 /.

The disadvantages of the known methods of constructing a slab-pile foundation are the significant material consumption of the pile field and the complexity of its construction due to the underutilization of the bearing capacity of the piles of the central zone of the pile field.

The technical problem is to reduce the complexity and material consumption of the slab-pile foundation for a high-rise building.

The problem is solved in such a way that in the method of constructing a pile-slab foundation of a high-rise building, including a foundation pit, a pile field and concreting a foundation slab, according to the invention, a pile field is arranged over the entire area of the pit from bored or driven piles of the same length, after which each pile the central zone of the pit, jacks are installed and alternately apply a load of 0.8-1.0 calculated load on the pile, with subsequent removal of the load after conditional stabilization of the wasp pile piles for equalizing the stiffness coefficient between piles of the central and peripheral zones of the base plate.

The proposed method differs from the known one in that the pile field is arranged over the entire area of the pit from bored or driven piles of the same length, after which jacks are installed on each pile of the central area of the pit and, alternately, a load of 0.8-1.0 rated load is applied to pile, with subsequent removal of the load after conditionally stabilizing the pile upset to equalize the stiffness coefficient between the piles of the central and peripheral zones of the base plate.

It is known that the peripheral rows of piles of a pile field perceive load, 2 times, and angular - 3 times higher than the average load on the foundation piles. Therefore, peripheral piles are designed with a large diameter with reinforced reinforcement or piles of the central zone are designed with a larger length than peripheral piles, which leads to an increase in material consumption.

The parameters of the impact force on the pile of the central zone from the jacks are selected based on the fact that when compressing with a force of more than the calculated load, the load bearing capacity of the pile may occur, and less than 0.8 does not lead to optimal soil compaction.

During compression with an effort of more than the calculated load, cracks may occur, and less than 0.8 does not lead to optimal compaction of the soil between the piles in the central zone.

The technical result is to ensure uniform load distribution between piles, reducing the material consumption of the foundation and the complexity of its construction by aligning the stiffness coefficient of piles of the central and peripheral zones of the pile field.

The method is illustrated in the drawing.

Figure 1 presents the pile-slab foundation of a high-rise building, figure 2 - aa of figure 1.

The foundation consists of a pile field formed from bored or driven piles 1 immersed in the ground and reinforced concrete foundation slab 2. Jacks 3 are placed on the pile heads 1 in the central zone under the foundation slab 2.

The method is as follows.

Bored piles are made or driven piles of the same calculated length are immersed in the soil, forming a pile field over the entire area of the pit. Jacks are installed on the piles of the central zone of the pile field between the pile head and the reinforced concrete slab. After the foundation is installed, the piles of the central zone are alternately exposed to a load equal to 0.8-1.0 of the calculated load on the pile in the longitudinal direction until the draft is conditionally stabilized, followed by unloading. Compression of piles in the longitudinal direction ensures equalization of the stiffness coefficient between piles of the central and peripheral zones of the pile field and reduces the deflection of the foundation plate. Due to the redistribution of the load between the piles as a result of the equalization of the stiffness coefficient from the load of the high-rise building, the bearing capacity of the foundation also increases and it becomes possible to reduce the dimensions of the piles and reduce their number.

Example.

A foundation is being erected for a 35-story building of a skeleton-barrel structural scheme with increased requirements to limit the amount of deflection of the foundation. The foundation of the building is a continuous slab on a pile foundation of bored piles with a diameter of 800 mm and a length of 30 m. The soil foundation is represented by homogeneous sandy soils. The design load on the pile is 500 Tf.

To reduce the deflection of the foundation and the redistribution of the stiffness coefficient between the piles in the central zone of the pile field, they are preloaded one after the other, and then the load is removed after conditional stabilization of the draft using jacks installed on the heads of the piles with an force of 450-500 Tc.

As a result, the stiffness of the piles of the central zone increases, which leads to a decrease in the deflection of the foundation slab by up to 30% and a reduction in the number of piles in the central zone.

Information sources

1. RF patent No. 2275470, cl. E02D 27/34, publ. 04/27/2006

2. RF patent No. 2275470, cl. E02D 27/34, publ. April 27, 2006 / prototype /.

Claims (1)

A method of constructing a pile-slab foundation of a high-rise building, including a foundation pit and a pile field followed by concreting a foundation slab, characterized in that the pile field is arranged over the entire area of the foundation pit from bored or driven piles of the same length, after which jacks are installed on each pile of the central area of the pit and alternately apply a load with a value equal to 0.8-1.0 of the calculated load on the pile, with subsequent removal of the load after conditionally stabilizing the pile upset to equalize the coefficient the stiffness between the piles of the central and peripheral zones of the base plate.

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