RU2328577C2 - Method of existing buildings and constructions protection - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method of existing buildings and constructions protection in a working area of open development containing a non-load-bearing design includes installation of injectors from existing buildings and constructions side and fixing solution injecting in a ground, with subsequent ground excavation from development. Injectors are installed in a non-load-bearing design on distance from outer surface of last, and a fixing solution injecting is made in direction of existing building.

EFFECT: increase of efficiency and reliability of buildings and constructions protection in conditions of close site development.

2 cl, 1 ex, 2 dwg

Description

The invention relates to construction and relates to ensuring the safety of existing buildings in the construction zone.

There is a method of protecting foundations during construction near various workings and structures, including the erection of walls in the ground by driving pipes with flat connecting elements into the ground, with the formation of leading cavities in front of the pipes to facilitate clogging [1].

The disadvantages of this method are its complexity, material consumption, the possibility of the appearance of additional sediment foundations as a result of dynamic effects and enumeration of the soil.

There is a method of protecting existing buildings and structures from the negative impact of buildings under construction by installing between them walls of bored piles [2].

The disadvantages of this method are its complexity, material consumption, the inability to restore the initial stress-strain state of the base soils and foundations of the building.

Closest to the proposed method is a method that includes a device in the soil of a geotechnical barrier by introducing a series of vertical injectors into the soil along the propagation wave of a change in the stress-strain state of the soil and once or repeatedly pumping the cement mortar into the soil. The need for a second and subsequent injections of the solution into the soil is established on the basis of monitoring the stress-strain state of the soil of the base [3].

The disadvantages of this method when protecting near open reinforced workings is that there is a need to perform laborious and expensive work on immersion of injectors in the ground. In addition, for the immersion of the injectors, the presence of space between the enclosing structures of the workings and existing buildings and structures is necessary. If the workings adjoin the existing buildings and structures, the installation of a geotechnical barrier is not possible.

The technical task is to increase the protection efficiency of existing buildings, structures and underground utilities located near open pits, due to the joint construction of the open-pit building envelope and injectors.

The problem is solved in such a way that in the method of protecting existing buildings and structures in the area of the opencast mining device containing the enclosing structure, including installing injectors and injecting the fixing solution into the ground, according to the invention, the injectors are installed together with the openwork enclosing structure from the side of existing buildings and structures, and the injection of a fixing solution into the soil is carried out in the direction of existing buildings and structures with subsequent exposure atsiey lot of production. Moreover, the injectors can be installed inside the building envelope, from the side of existing buildings and structures. In addition, the injection of the fixing solution can be performed repeatedly, during and after excavation of the soil from the excavation, depending on the results of monitoring the stress-strain state of the soil of the base.

The proposed method differs from the known one in that the power elements - open-guard fencing structures are arranged in conjunction with the active elements - injectors periodically arranged from the side of existing buildings and structures, through which, after the end of the fencing device, but before excavation of the excavation soil, they actively act on the adjoining from the outside of the excavation of the soil - restore the initial stress-strain state and increase the mechanical properties of the soil base fun Damenty of existing buildings and structures by forcing a fixing solution into the ground through a system of injectors. Injectors are installed inside the fence structure or close to it from the side of existing buildings and structures.

During excavation of the excavation soil and after its completion, the injection of the fixing solution into the soil through a system of injectors can be performed repeatedly, depending on the results of monitoring the stress-strain state of the soil of the base.

The method is illustrated by drawings, where in Fig.1 shows a diagram of the device of the pit using active fences, Fig.2 - 1-1 of Fig.1.

An example of the protection of an existing building located close to the pit.

Close to the foundations 1 of the existing building, a pit is arranged, the enclosing structures of which are bored piles 2.

Geotechnical parameters of active fences: the number of injectors, the length and position of the perforated section of the injector, the composition of the solution, the injection pressure of the solution, the radius of fixation and the characteristics of the fixed soil, the volume of the solution injected into the soil is assigned taking into account the simulation data of changes in the stress-strain state of the soil mass as a result of static and technological impacts as a result of excavation and experimental work at the facility.

The parameters of active fences are selected so that the predicted additional deformations (maximum additional draft, maximum relative difference of draft, maximum additional roll, maximum additional curvature of the base of the foundation) of the building foundations from the influence of tunnel penetration do not exceed 10 ... 30% of the limit values.

They arrange a wall from bored piles 2. They drill a well under the protection of casing pipes and fill the well with concrete. On the armokarkasa, injectors 3 of the cuff-tampon type are fixed, and lowered into the well. Injector 3 have openings closed by cuffs, which are located on the side of the existing building. The injector is installed so that the minimum distance between the injector and the outer surface of the pile is not more than 1 cm. Lift the casing.

After the hardening of concrete in bored piles 2 through the injector 3, compaction and consolidation of the soil is carried out by a single injection of cement mortar into the soil using a high pressure sleeve 4. At the beginning, the injection pressure of the mortar should be such as to allow the protective layer of concrete to be destroyed and the cement mortar to be injected into the ground. The purpose of the zero injection cycle is to check the entire injection system, initial “pressure testing” (precompression, compaction and consolidation) of the soil, comparing the predicted design response of the building to the injection of the solution and, as a result, updating the adopted compensation compensation method. The injection is performed until the required volume of solution is injected into the soil or a reaction of the protected building is detected - raising its foundations to 3 mm. In the process of injection, periodic cycles of engineering and geodetic measurements of the vertical movements of the foundations are performed. After that, excavation of the soil is carried out from the excavation with the device of strapping beams 5 and struts 6.

In the process of constructing the pit, periodic engineering and geodetic measurements are performed. After additional deformations of the building reach 10 ... 30% (not less than 5 mm) of the limiting values, the first and subsequent cycles of compensatory injection of the solution into the soil are carried out through a system of injectors 3 located in the body of the bored pile 2. In this case, the discharge pressure the solution is initially increased to the pressure P _{gi of the} hydraulic fracture, which expands after each injection of the "shell" from the reinforced soil. Then the pressure is reduced to a value of 0.8 * P _gri . Compensatory pumping is carried out until the initial stress-strain state of the foundation soils and foundations of the building is restored, and its foundations are raised and leveled. A slight rise of the building up to 3 mm is allowed.

After the excavation of the pit and the completion of construction work, the final pumping cycle is performed to fix the stress-strain state of the base soil.

The technical result of the invention is: reducing the negative impact of opencast mining on the technical condition of nearby buildings, structures and underground utilities; increasing the efficiency and reliability of their protection in the context of tight development; the possibility of generating devices at a distance from existing buildings to 0.2 m or less.

Information sources

1. RF patent No. 2023811, cl. E02D 5/20, BI No. 22, 11/30/94.

2. Recommendations on the design and installation of foundations and foundations for the construction of buildings close to existing in conditions of dense urban development in Moscow. 1999 year

3. RF patent No. 2245966, cl. E02D 31/08, BI No. 5, 2005.02.10 (prototype).

Claims (2)

1. A method of protecting existing buildings and structures in the area of an open-cut mining device containing a building envelope, comprising installing injectors from the side of existing buildings and structures and injecting a fixing solution into the ground, followed by excavating the soil from the excavation, characterized in that the injectors are installed inside the building envelope at a distance from the outer surface of the latter, and the injection of the fixing solution is carried out in the direction of the existing building. 2. The method according to claim 1, characterized in that the injection of the fixing solution is carried out repeatedly during and after excavation of the soil from the excavation.

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