RU2422592C1 - Method to maintain initial stressed-deformed condition of soil in zone of existing building foundation - Google Patents

Abstract

FIELD: construction. ^ SUBSTANCE: method to erect underground structures in an area of city development includes arrangement of a geotechnical barrier in soil between foundations of the existing building and an erected underground structure with its closing for a rated depth, erection of walls and a bottom of the underground structure. At the same time the geotechnical barrier is arranged at a rated distance from the foundation of the existing building in the form of a row of vertical drilled-injection piles with a pitch, at the same time each of them is arranged in the following manner: a conductor is installed into a previously drilled process well, filled with a cement solution with subsequent time delay until full gain of the cement solution strength. Then the formed cement stone is drilled inside the conductor, and the process well is additionally drilled to the rated depth, and then a special well monitor is lowered with side nozzles, and a washing cement solution is supplied to the monitor along a flexible sleeve, and this solution, outgoing from the side nozzles of the monitor in the form of a high-speed jet, washes the specified rated volume of soil, forming a washed cavity (a cavern), filled with a soil-cement mixture. Afterwards the well monitor is extracted from the process well, a packer is installed in its place, and simultaneously, near the process well, there are vertical collar injectors installed, so that holes of injectors are arranged in the washed cavity (the cavern), and the controlled injection of the cement solution is carried out. ^ EFFECT: maintaining initial stressed-deformed condition of soil in the zone of the existing building foundation. ^ 2 cl, 1 dwg

Description

The invention relates to the field of construction, mainly to technologies for laying the foundations of structures erected in the urban area near existing buildings. There is a method of erecting underground structures in the urban area, including the device in the ground of a geotechnical barrier in the form of a separation structure between the foundation of the existing building and the erected underground structure with its closure at the calculated depth, the construction of the walls and the bottom of the underground structure (1). The device in the soil of the separation fence is carried out by loosening around the erected soil structure and crushing the sheet piling with the subsequent installation of a clay curtain from a clay solution. Then they begin to erect the walls of the underground structure. The disadvantage of this method is its complexity and the inability to prevent changes in the stress-strain state of the soil under the foundation of an existing building, which can lead to settlement of the foundation more than acceptable values.

The closest technical solution, selected as a prototype, is a method of erecting underground structures in the urban area (2), including the installation of a geotechnical barrier between the foundation of the existing building and the erected underground structure with its closure at the calculated depth, the construction of walls and the bottom of the underground structure, this geotechnical barrier is arranged by introducing into the ground a number of vertical injectors on the path of wave propagation of changes in the stress-strain state of the soil producing pumping grout up to the calculated volume. The disadvantage of this method is the small amount of impact on the soil mass and the mismatch of the directions of the vertical stresses from the settling foundation with the horizontal direction of the compressive stresses of the soil from the geotechnical barrier.

The technical task is to prevent changes in the stress-strain state of the soil under the foundation of an existing building during the construction of an underground structure next to it.

This is achieved by the fact that in the method of maintaining the initial stress-strain state of the soil in the foundation zone of an existing building, including the installation in the ground of a geotechnical barrier between the foundations of the existing building and the constructed underground structure with its closure to the calculated depth, the construction of the walls and the bottom of the underground structure, according to the invention the geotechnical barrier is arranged as follows: a conductor with a diameter larger than the diameter is installed in a pre-drilled technological well meter of the technological well, the conductor is filled with cement mortar, followed by a temporary exposure until the cement slurry is fully set, then the formed cement stone is drilled inside the conductor, and the technological well is drilled to the calculated depth (h), then the downhole monitor with side nozzles is lowered into the technological well and fed to the monitor along the flexible sleeve, the erosive cement mortar, which, leaving the side nozzles of the monitor in the form of a high-speed jet, produces an erosion set of the calculated soil volume, forming a blurred cavity (cavity) in it, filled with a cement-cement mixture, after that a downhole monitor is removed from a technological well, a packer is inserted in its place, and at the same time, vertical cuff injectors are installed next to the technological well so that the holes of the vertical cuff injectors were located in a diffuse cavity (cavity) and produce a controlled injection of cement mortar until a specified stress-strain state r foundation root of the existing foundation.

The proposed method differs from the known one in that the geotechnical barrier is arranged by underground erosion of the soil using a downhole monitor with horizontal jets from pre-drilled technological wells with the formation of cavities in the soil of specified shapes and sizes and the simultaneous filling of these cavities with a hardening solution through vertical cuff injectors.

The proposed method allows you to maintain the initial stress-strain state of the soil in the foundation zone of an existing building in the process of erecting a ground structure, which makes it possible to reduce vertical and horizontal movements to the maximum permissible values.

The proposed technical solution is illustrated by the drawing, which shows the technological scheme of the implementation of this method.

The method of maintaining the initial stress-strain state of the soil in the foundation zone of an existing building is as follows. First, a technological well (1) is drilled and a conductor (2) is installed in it, moreover, the diameter of the conductor is larger than the diameter of the technological well. Then the conductor (2) is filled with cement mortar and give time for a complete set of strength of the poured cement mortar. Next, the formed cement stone is drilled inside the conductor (2), and the technological well (1) is drilled to the calculated depth (h), and the depth of the technological well (1) should be greater than the depth of the base of the foundation of the existing structure (3). Then, a downhole monitor (4) having side nozzles is lowered into the drilled technological well (1). A cement slurry is supplied to the downhole monitor (2). At the same time, a high-speed stream of cement mortar (5) leaves through the side nozzles, which erodes the soil, forming a horizontal cavity in it (6). If the downhole monitor (2) is rotated around the vertical axis and at the same time they begin to slowly raise, then, as the rotated downhole monitor (4) rises, a part of the soil washed out by the rotated stream (within the radius of the erosion ability of the stream) is mixed with the solution and In the image, a cylindrical blurred cavity (7) is formed in the soil massif, filled with a cement-cement mixture. After that, the downhole monitor (4) is removed from the production well (1) and a packer (not indicated) is installed in its place. At the same time, vertical cuff injectors (8) are driven in such a way that their openings are located in a diffuse cavity (6) or (7). And produce a controlled injection of cement mortar under a pressure equal to or greater than the pressure under the foundation. In the process of injection, they monitor the movement of the foundation of an existing building and, in accordance with the movements, change the mode of injection of cement mortar. There can be several such injection modes, each subsequent one with a pressure exceeding the pressure in the previous injection mode. After the cement mortar hardens, a geotechnical barrier is formed in the form of a horizontal formation (6) or a cylindrical column (7).

Information sources

1. Patent of Russia, No. 2042013, cl. E02D 29/045, BI No. 23, 08.20.95.

2. Patent of Russia, No. 2245966, cl. E02D 31/08, BI No. 35, 12.20.2008.

Claims (2)

1. A method of maintaining the initial stress-strain state of the soil in the foundation zone of an existing building, including the installation of a geotechnical barrier in the ground between the foundation of the existing building and the underground structure being constructed with its depth being fixed, the walls and the bottom of the underground structure being erected, characterized in that the geotechnical barrier arrange as follows: a conductor is installed in a pre-drilled technological well, it is filled with cement mortar, followed by with a slow shutter speed until the cement mortar is fully cured, then the formed cement stone is drilled inside the conductor, and the technological well is drilled to a depth exceeding the depth of the foundation foundation of the existing building, and then the downhole monitor with side nozzles is lowered and the erosive cement mortar is fed to the monitor through a flexible sleeve which, exiting the side nozzles of the monitor in the form of a high-speed jet, erodes the specified design soil volume, forming a blurry a cavity (cavity) filled with a cement-cement mixture, after that a downhole monitor is removed from a technological well, a packer is inserted in its place, and at the same time, vertical cuff injectors are installed next to the technological well so that the openings of the cuffed injectors are located in a diffuse cavity (cavern) , and produce a controlled injection of cement to maintain the initial stress-strain state of the soil in the foundation zone of an existing building in the process of eniya underground structure. 2. The method of maintaining the initial stress-strain state of the soil in the foundation zone of an existing building according to claim 1, characterized in that the technological well is made with a diameter smaller than the diameter of the conductor.

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