RU2352722C1 - Method for reinforcement of building foundation - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method for building foundation reinforcement includes development of trench along reinforced building foundation, arrangement of indents in building wall, reinforcement of foundation grill and its further concreting with provision of holes, through which tubular sections of piles are jacked, at that every pile section is connected between each other by means of transition collar. After design pressure is obtained by piles, they are armored and concreted simultaneously with openings. Openings are shaped as conical since in process of foundation grill reinforcement, in place of openings creation, there are shape-generating conical elements installed, which expand in direction of piles jacking, at that their taper is selected within the limits of 0.17-0.50.

EFFECT: improved reliability of reinforced building foundation.

3 cl, 5 dwg

Description

The invention relates to the field of construction and can be used in the reconstruction of existing foundations.

There is a method of strengthening the foundation of a building, in which cylindrical holes are drilled through the foundation through which sectional crushing of piles to a predetermined depth is carried out, while fixing the head section of the pile is carried out before crushing the head section of the pile, injecting a quick-hardening adhesive composition, and after crushing the head section, the pile is kept under load until the end of the gluing process (patent for invention RU 2057847, IPC 6 E02D 27/08, published September 15, 1996).

The disadvantage of this method is the complexity of the technology, in which holes for the passage of piles are drilled in the concrete body of the foundation, which requires the use of additional equipment and complicates the process of erecting the foundation.

The closest technical solution is the method described in the patent for invention RU 2144111, IPC 7 E02D 27/48, published on 10.01.2000. This method includes transplanting the foundation onto the remote section piles, which are pressed with a hydraulic jack through the cylindrical holes of the grillage formed during its concreting. After installing the piles, they are reinforced with a single rod and concreted with holes.

A disadvantage of the known method is the low reliability of the pile-grill coupler, since during prolonged exposure to loads and / or the appearance of additional loads from the grill (foundation slab) and / or upstream building structures, piling through the grill (foundation slab) can occur, which leads to to partial or complete loss of the bearing capacity of the foundation and its destruction.

An object of the present invention is to provide a method for improving the reliability of a reinforced building foundation.

The problem is solved due to the fact that the method includes the development of a trench along the reinforced foundation of the building, installation of grooves in the wall of the building, reinforcing the grillage and its subsequent concreting with the formation of holes through which the tubular sections of the piles are crushed. Each section of the piles is connected to each other by a transition cuff, and after the piles reach the design pressure, they are reinforced and concreted simultaneously with the holes. Holes form conical. To do this, when reinforcing the grillage in the place of formation of the holes, form-forming cone-shaped elements are installed, expanding in the direction of crushing the piles, while their taper is chosen in the range 0.17-0.50. Piles can be reinforced with a single rod or spatial frame.

The proposed method of strengthening the foundation of the building allows to increase the reliability of the foundation and prevent its destruction by reducing the load on the grillage at the location of the piles.

The essence of the proposed method is illustrated in figures 1-5, illustrating the method of strengthening the foundation.

Strengthening the foundation is as follows.

Along the existing foundation of the building, a trench 1 is developed, and a trench 2 is made in the foundation of the building, in the area of which holes 3 are drilled (Fig. 1), into which the anchor rods are installed 4. Then the grillage is reinforced and technological anchors 5 are mounted for fixing the installation 6 and forming cone-shaped elements 7, which are placed in the place of formation of holes for the passage of piles (Fig.2-3), set the formwork 8. In this case, the cone-shaped elements are installed so as to form a hole Ie, expanding in the direction of crushing piles. After that, the grillage 9 is concreted, and when concrete reaches 60% of the design strength (which is at least 7 days), they begin work on the installation of piles 10 (Fig. 4). Piles are performed using shock-free technology by the method of static crushing of sections of piles, during which mandatory control of the efforts of immersion piles is performed. In this case, the first section has a cone-shaped tip, which provides better conditions for the passage of soil and prevents the latter from entering the pile cavity. The sections are interconnected by welding to a transition cuff made of a pipe of smaller diameter. Crushing of sections of piles is carried out until the pressure is fixed on the manometer of installation 6 of such pressure, which corresponds to an excess of the calculated bearing capacity of the pile by 1.2 times. Then the cavity of the pile reinforced with a single rod 11 or spatial frame (depending on the design characteristics) and filled with concrete simultaneously with a conical hole. As a result, at the junction of the grillage with the pile, a cone-shaped plug 12 (Fig. 5) is formed, formed by the shaping cone-shaped element 7. The conicity of the shaping element 7 is 0.17-0.50.

Long-term action of loads, the appearance of additional loads from the grillage (foundation slab) and upstream building structures can lead to extrusion of piles through the grillage (foundation slab), loss of the bearing capacity of the foundation and its destruction. The increase in the surface area of friction in the node of the interface between the pile-grillage neutralizes the harmful effect of the loads that cause the extrusion of the pile through the grillage. This increase in area is realized due to the formation of a conical-shaped friction surface. The limiting values of the taper are determined by calculation and depend on such parameters as the height of the grillage, the pitch of reinforcement and the diameter of the piles. The minimum taper value of 0.17 was calculated for the maximum height of the grillage. In this case, the friction surface area is increased due to the height of the grillage and a large taper value is not required. The maximum taper value of 0.50 was calculated for the minimum height of the grillage, while the value of 0.50 is limited by such parameters as the step of reinforcing the grillage and the diameter of the piles.

An example implementation of the method.

Along the existing foundation of the building, a trench 600 mm wide to a depth of 800 mm is being developed. Then, in the foundation, a pit is made to a depth of 300 mm, in the area of which bore holes are drilled. In the holes set anchor rods F 25 A III. Then reinforce the grillage; the step of reinforcing the grillage is 400 mm. Simultaneously with the reinforcement, technological anchors F 25 A III are installed to fix the installation, and also form-forming cone-shaped elements with a taper of 0.37 are installed. After that, the grillage is concreted using concrete of class B25. Upon reaching concrete strength of 60%, they begin work on the installation of piles. Piles are performed using shock-free technology by crushing inventory pipes-shells Ф 159 × 6 mm to a depth of 10 m. The elements of the pipe-shells are connected together by welding. The pile is reinforced with a single rod F 25 A III for the entire length, and then the pile is concreted with the conical hole.

The cone-shaped plug formed in this way increases the reliability of the foundation and prevents its destruction by reducing the load on the grillage at the location of the piles, since the effects of the loads leading to the extrusion of the pile through the grillage are more evenly distributed in the grillage body. In addition, the orientation of the cork in the grill, in which the cone with its expanding part is oriented in the direction of crushing the piles, creates a jamming effect, which also prevents the extrusion of piles through the grill (foundation plate).

The proposed method allows the formation of a conical plug in the process of strengthening the foundation, which improves the reliability of the foundation at the location of the piles.

Claims (3)

1. A method of strengthening the foundation of a building, including the development of a trench along the reinforced foundation of the building, the device in the wall of the building strokes, reinforcing the grillage and its subsequent concreting with the formation of holes through which the tubular sections of the piles are crushed, and each section of the pile is connected by a transition sleeve, after when the piles reach the design pressure, they are reinforced and concreted simultaneously with the holes, characterized in that the holes are cone-shaped due to the fact that when reinforced On the basis of the grillage, in the place of formation of the holes, form-forming cone-shaped elements are installed, expanding in the direction of crushing the piles, while their taper is chosen in the range 0.17-0.50. 2. The method of strengthening the foundation according to claim 1, characterized in that the piles are reinforced with a single rod or spatial frame. 3. The method of strengthening the foundation according to claim 1, characterized in that the sections of the piles are interconnected by welding to a transition cuff.

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