RU2328576C1 - Method of slab-pile foundation erection - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method of a slab-pile foundation erection on loose grounds includes compaction of ground near piles, immersing of vertical piles in a ground and arrangement of slab raft foundation. At first on earth foundation a casing is installed, ferro fabric is mounted and bottom part of a slab-raft is concreted in height not less than 100-150 mm with through holes under piles. When concrete will be strengthen through holes a driven wells are drilled on depth of 1-2 m and piles are stemmed in a ground with simultaneous compaction of a ground near piles under a slab-raft with subsequent embedment of holes of a slab-raft bottom part by concrete. Then on a slab-raft bottom part a waterproof finish is carried out, then a casing and ferro fabric of slab-raft upper part are installed and monolithic reinforced concrete slab is erected.

EFFECT: increase of a slab-pile foundation load-carrying capacity and simplification of its arrangement due to prevention of ground de-compaction under a foundation slab.

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Description

The invention relates to the construction, namely, the construction of pile foundations on soft soils.

A known method of construction of a pile foundation on soft soils, including compaction of the soil by deep vibration and immersion piles / 1 /.

A known method of construction of a pile foundation on soft soils, including immersion of long piles around the perimeter of the foundation and compaction of the soil by impact by tamper, followed by immersion of a short pile in the center of the compacted zone / 2 /.

A disadvantage of the known methods is the high complexity due to the immersion of piles in compacted soil, the high resistance of which makes it difficult to use long piles, and therefore leads to a decrease in the bearing capacity of the pile foundation.

Closest to the proposed method for the construction of a pile foundation with a slab-grill is a method that includes immersion of piles and simultaneous compaction of the near-pile soil, followed by the device of the slab-grill foundation / 3 /.

The disadvantage of this method is the complexity of the construction work due to the need for dynamic effects on the soil and insufficient bearing capacity of the foundation, which is determined by the length of the piles.

The technical problem is to increase the bearing capacity of the slab-pile foundation, simplifying its construction by preventing decompression of the soil under the foundation slab and the possibility of waterproofing the pile foundation.

The problem is solved in such a way that in the method of erecting a slab-pile foundation on soft soils, including compaction of near-pile soil, immersion of vertical piles in the ground and the construction of a foundation slab, according to the invention, the formwork is first installed on the soil foundation, the arm frame is mounted and the lower part is concreted. grill slabs with a height of at least 100-150 mm with through holes for piles, and after gaining strength with concrete, holes are drilled through holes to a depth of 1-2 m and the piles are driven into the ground okolosvaynogo simultaneous compaction of soil under the plate-grillage with subsequent embedment of the bottom of the holes-plate grillage concrete, then on the bottom-plate grillage operate waterproofed, whereupon the formwork and reinforcement mounted upper part of the plate-grillage and erecting a monolithic reinforced concrete slab.

The proposed method of erecting a slab-pile foundation on soft soils differs from the known one in that, first, formwork is installed on the soil foundation, an armature frame is mounted and the lower part of the grillage is concreted with a height of at least 100-150 mm with through holes for piles, and after concrete has set strength wells are drilled through the holes to a depth of 1-2 m through the holes and piles are driven into the soil with simultaneous compaction of the near-pile soil under the grillage slab with subsequent monolithic openings of the bottom of the grillage concrete slab m, then on the bottom-plate grillage operate waterproofed, whereupon the formwork and reinforcement mounted upper plate portion and erected grillage monolithic reinforced concrete slab.

The device of the slab-grillage from two parts of the lower and upper with the proposed sequence of technological operations and preliminary drilling of wells to a depth of 1-2 m before driving piles significantly reduces the complexity of the work, eliminates the softening (restructuring) of the soil of the upper part of the soil base and the deformation of the grill-slab, and also perform reliable waterproofing of the pile foundation. The depth of the preliminary drilling is due to the deformability of the soil.

The proposed sequence of work - first, the device of the lower part of the grillage, and then immersion of piles through the plate - allows without additional impact on the soil to avoid softening of the soil when driving piles and increase the bearing capacity of the foundation.

The technical result of the proposed technology for the construction of a slab-pile foundation is to reduce precipitation and reduce the complexity by reducing the number of piles and eliminating the operation of cleaning the soil of the base of the slab-grillage and increasing the reliability of the waterproofing of the underground structure.

The height of the lower part of the grillage slab should be at least 100-150 mm and is due to the possibility of working on the plate of heavy equipment for driving piles and carrying out waterproofing, and the height of the upper part is determined by calculation depending on the loads acting on the foundation (building weight).

The method is illustrated in the drawing, which shows a plate-pile foundation.

The method is as follows.

On the soil base 1, formwork is installed (not shown in the drawing) and the reinforcement cage 2 of the grillage plate 3 is mounted. The lower part of the grillage plate 3 with through holes 4 with a height of 150 mm is concreted. After concrete has gained strength through holes 4, wells are drilled with a diameter corresponding to 0.6-0.8 of the diameter of the pile (side of the square section of the pile), to a depth of 1-2 m, depending on the deformability of the soil, and pile 5 to the design mark. Then monolith holes 4 concrete. Then, waterproofing is carried out on the surface of the lower part of the grillage slab 3. After that, the formwork and reinforcement cage of the upper part of the grillage slab are installed and a continuous monolithic reinforced concrete slab 7 is erected with a height of 500-800 mm, calculated on the construction of a 17-story building. The total height of the grillage slab is taken 600-900 mm. Especially effective is such a foundation device in two stages when building on soft soils.

When the loads acting on the foundation change, the thickness of the upper part of the grillage plate will change.

Information sources

1. SU Copyright certificate No. 1565965, cl. E02D 27/12, publ. 05/23/1990.

2. SU Copyright certificate No. 1498891, cl. E02D 7/02, publ. 08/07/1989.

3. RF patent No. 2258114, cl. E02D 27/12, publ. 08/10/2005 / prototype /.

Claims (1)

A method of constructing a slab-pile foundation on soft soils, including compaction of near-pile soil, immersion of vertical piles in the ground and the construction of a foundation slab, characterized in that the formwork is first installed on the soil base, an armature frame is mounted and the lower part of the slab is concreted with a height of not less than 100-150 mm with through holes for piles, and after gaining concrete strength, holes are drilled through holes to a depth of 1-2 m through holes and piles are driven into the soil with simultaneous compaction of the near-pile soil one slab-grillage followed by monolithic holes in the lower part of the grillage slab with concrete, then waterproofing on the bottom of the grillage slab, formwork and reinforcement cage of the upper part of the grillage slab and erect a monolithic reinforced concrete slab.