RU2338033C1 - Method of erection of concrete in situ piles in laminated driven wells - Google Patents

Abstract

FIELD: building.

SUBSTANCE: invention concerns foundation engineering in particular to methods of increase of a load-carrying capacity of friable and weak priming coats, including, possessing specific, collapsible, salted and other properties. The way of erection of concrete in situ piles includes the following technological operations: formation of a longitudinal hollowness of a driven well in a vertical or slope direction without dredging and lamination of a cylindrical-taper driven well by ground extruding using a fusiform roller in a nearby borehole space, thus forming the condensed working area of a driven well, filling of a driven well with the concrete mix not lower than B 3.5 class. Thus radius of the condensed working area is defined under the formula:

and the expense of concrete for driven well filling is defined under the formula: V₀=(πd²/4)·(l_c+(1/3)·l_k), where: d - diameter of a forming (cylindrical) roller of driven wells, m; ρ_d - initial (to lamination) consistency of the soil in a dry condition, t/m³; ρ_dS - consistency of the soil in a dry condition in the condensed working area, t/m³; d - diameter of the stilt, m; l_c - length of a cylindrical lot of the driven well, m; l_k - length of a cone-shaped lot of the driven well, m; L - length of a stilt, m.

EFFECT: improvement of quality and a load-carrying capacity of erected stilts.

2 cl, 4 dwg

Description

The invention relates to fundamental engineering, in particular to methods of increasing the bearing capacity of loose and soft soils, including those having specific, subsidence, heaving, saline and other properties.

A known method of constructing a stuffed pile in the soil [1], including the formation of a leader well using special mechanisms, lowering a metal casing into the leader well, feeding plastic concrete mix to the casing, compacting the concrete mixture in the casing, which is simultaneously removed from the well. After the concrete mixture has hardened, a concrete stuffed pile is obtained. The disadvantage of this method is the low bearing capacity of the piles due to the minimum inclusion in the work of a smooth side surface, the relatively high complexity of concreting the wellbore.

A known method of construction in the soil of a printed pile [2], selected as a prototype and including the formation using special mechanisms of the leader well with its subsequent concreting.

The disadvantages of this method is the low degree of compaction of the walls of the well and the involvement of near-wellbore space in the work of the soil, which when used in loose and weak soils can lead to their collapse.

The objective of the invention is the creation of technology for the construction of piles in the construction of facilities on loose and soft soils with specific properties.

The problem is solved due to the fact that in the method of erecting a concrete stuffed pile, including the formation of a well in a vertical or inclined direction without excavating and then concreting it, according to the invention, a cylindrical-conical well is first formed by a spindle-shaped reamer and rolled out by displacing the soil with a spindle-shaped reamer into the borehole space, while forming a compacted zone of the borehole space, then fill the well with a movable concrete all class not lower than B 3.5, followed by vibration compaction, while the radius of the sealed zone near the borehole is determined by the formula:

and concrete consumption for filling the well is determined by the formula:

Where:

d is the diameter of the forming (cylindrical) roller of the borehole roll, m;

ρ _d - initial (before rolling) the density of the soil in the dry state, t / m ³ ;

ρ _dS is the density of the soil in the dry state in the compacted zone, t / m ³ ;

D is the diameter of the pile, m;

l _c - the length of the cylindrical section of the well, m;

l _k is the length of the conical section of the well, m;

L is the length of the pile, m

In addition, the rolling of wells in low-moisture sand, hard and plastic sandy loams, as well as hard to soft plastic loams and clays is carried out with the addition of water 0.5 ÷ 1.5 l per 1 meter of rolling of the well.

The technical result provided by the above set of essential features is to improve the quality and bearing capacity of the piles being built, used as a foundation or to strengthen weak foundations of foundations of emergency and reconstructed buildings and structures. The application of this method allows to increase the bearing capacity of loose and weak soils, as well as soils with specific subsidence, swelling, heaving and saline properties (capable of maintaining the stability of wells rolled out in them for at least one hour).

The proposed technical solution is illustrated by drawings, in which Fig. 1 shows a structural diagram of a rolled up vertical pile, and Fig. 2 shows an inclined pile, and Fig. 3 shows a general view of the change in the density of the soil in the dry state (ρ _dS ) in the near-pile space depending on the initial (before the expansion of the well) dry density of the soil (ρ _d ) and the diameter of the reamer d = 2r, Fig. 4 shows the expansion of a cylindrical-conical well with a spindle-shaped reamer to the design depth.

The method is as follows.

First, a spindle-shaped roll (1) creates a cylindrical-conical well (2). In the process of rolling the well (2), the soil is not exposed to the surface, but is rolled in by a spindle-shaped roll with the addition of water into the array surrounding the well and, thus, a compacted zone (3) of the near-borehole space is formed. The radius of the compacted zone near the borehole space is determined by the formula (a), concrete consumption by the formula (b). The required soil density (ρ _dS ) is determined according to the schedule (Fig. 3), constructed according to formula (a), based on the actual values (ρ _d ) of the rolled soil and the diameter (d) of the spindle-shaped roll.

In the rolled cylindrical-conical well (1), a mobile concrete mixture with a class of at least B 3.5 is supplied, followed by vibration compaction. In the case of work in winter conditions, antifreeze additives are introduced into the concrete mixture. After the concrete mixture has hardened, the pile constructed in this way can be used as a supporting structure.

Wells are drilled in wet sand (W≤Woopt) sands, hard and plastic (I _L ≤0.9) loams, and also hard to soft plastic loams and clays with (I _L ≤0.7) with the addition of water 0.5 ÷ 1.5 l per 1 running meter of well rolling.

Information sources

1. Kosolapov V.G. Sawing and drilling equipment for pile work. M., Higher School, 1978, p. 195.

2. Patent of Russia No. 2150549, Cl. E02D 5/34, 2000

Claims (2)

1. The method of construction of concrete rammed piles in rolled wells, including the formation of a well in a vertical or inclined direction without excavation and its subsequent concreting, characterized in that at first the spindle-shaped roll forms a cylindrical-conical well and roll it out by displacing the soil with a spindle-shaped roll in a near-borehole the space, while forming a compacted zone of the near-borehole space of the well, then fill the cylindrical-conical well with a movable concrete mixture not lower than class B 3.5 with subsequent vibration compaction, while the radius of the compacted zone near the borehole is determined by the formula

and concrete consumption for filling a cylindrical-conical well is determined by the formula

where d is the diameter of the cylindrical part of the spindle-shaped roll of the well, m; ρ _d - initial (before rolling) the density of the soil in the dry state, t / m ³ ; ρ _dS is the density of the soil in the dry state in the compacted zone near the borehole space, t / m ³ ; l _c - the length of the cylindrical section of the well, m; l _k is the length of the conical section of the well, m; 2. The method according to claim 1, characterized in that the rolling of a cylindrical-conical well in low-moisture sands, hard and plastic sandy loams, as well as hard to soft plastic loams and clays is carried out with the addition of water 0.5 ÷ 1.5 l per linear meter rolling wells.

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