RU131747U1 - ANTI-FILTRATION SCREEN - Google Patents

Abstract

The utility model relates to the field of construction and can be used in the engineering preparation of construction sites in order to protect the foundation pit for a building under construction, construction from filling it with groundwater coming from the sides of the pit, and through its bottom in the case when the filtering coefficient of the surrounding soil exceeds permissible norms. In addition, the utility model can be used to enhance the watertightness of dams enclosing ponds. The antifiltration screen is made in the form of a single soil-cement reinforced massif, consisting of metal, non-recoverable injectors in the form of pipes with a diameter of 32-92 mm, which have blind and perforated parts, driven into pre-drilled wells arranged in a checkerboard pattern in several rows, and through injectors into the soil under load introduced injection clay-bentonite-cement or cement-sand mortar, and the distance between the injectors is inversely dependent on the filtration coefficient saturated soil at the place of work. According to a useful model: - when working on slopes, all injectors are tied by welding at ground level with round steel with a diameter of 10-40 mm or steel wire; - when strengthening dams enclosing ponds, the screen covers the entire body of the dam, and the depth of the injectors is the sum of the height of the dam, the depth of the pond and 100-200 cm below the bottom of the pond; - the screen is made two-row, or three-row, or continuous over the entire area of the reinforced water-saturated soil, and its depth exceeds the depth of the water-saturated soil by 100-150 cm; - in one well there are several injectors of various heights, designed for cementation of different layers of soil, and the perforated part of each subsequent injector is located below the perforated part of the previous one, without blocking it; - wells drilled vertically and / or obliquely, or by beam divergence; - each injector is fixed in the well by a packer, which can be both superficial and deep; - the injection solution injected into the injectors contains at least 30% cement, 70% clay and bentonite, or part of the clay is replaced by fine sand, in addition, the solution may contain liquid sodium or potassium glass at a rate of 3-5 kg per 1 cubic meter solution; - the perforated part of the injector does not exceed 10-12 m. The use of the utility model can increase the efficiency and expand the scope of the anti-filter screen, simplify and reduce the cost of work on its creation. 2 ill.

Description

The utility model relates to the field of construction and can be used in the engineering preparation of construction sites in order to protect the foundation pit for a building under construction, construction from filling it with ground water coming from the sides of the pit, and through its bottom in the case when the filtering coefficient of the surrounding soil exceeds permissible norms. In addition, the utility model can be used to enhance the watertightness of dams enclosing ponds.

Pile structures are currently widely known for arranging anti-filter screens, for example, an anti-filter engineering and protective structure, which includes drill-injection piles made in the ground at a distance from each other (RF patent No. 2111283, IPC E02D 5/56, published on 08.27.2003) . Piles are performed by immersion in the soil of a monolithic body of revolution, then at the mouth of the formed well with an inserted body of revolution, a fixed and / or antifiltration material is fed and the body of rotation is unscrewed to the surface due to its reverse rotation.

The disadvantages of pile structures are the difficulty of installing on the site between the existing building and the excavated foundation pit the powerful equipment necessary for the installation of piles, as well as the dynamic effects on nearby buildings from the operation of such equipment. In addition, it is impossible to perform work in steep slopes, on rocks, in cramped conditions due to the danger of soil movement or subsidence.

Known technologies are “wall in soil”, for example, according to RF patent No. 2447228 (IPC E02B 3/16, published April 10, 2012) an anti-filtration screen is obtained by digging a trench around the perimeter of a constructed screen into which cement mortar is pumped using high-pressure injection , and lay down the drainage pipes.

The disadvantage is the impossibility of digging trenches in cramped conditions during the work, as well as the possible creation of a complete barrage with a “wall in the ground” device, which will lead to a change in the direction of groundwater under the base of buildings and structures located in close proximity. In addition, work on well-known analogues have a high cost.

The objective of the utility model is to increase the efficiency and expand the scope of the anti-filter screen, simplify and reduce the cost of work on its creation.

The technical result is achieved by creating, as a result of the application of the utility model, an almost homogeneous technogenic array with low filtration properties and increased bearing capacity, as well as due to the possibility of screening on almost all types of soils for structures of various purposes.

The problem is solved by an anti-filter screen, made in the form of a single soil-cement reinforced array, consisting of metal, non-recoverable injectors in the form of pipes with a diameter of 32-92 mm, which have blind and perforated parts, hammered into pre-drilled wells located in staggered rows in several rows, and an injection of clay-bentonite-cement or cement-sand mortar was introduced through the injectors into the soil under the load, and the distance between the injectors is inversely related to ffitsienta filtration saturated soil at the job site.

According to the utility model:

- when working on slopes, all injectors are tied by welding at ground level with round steel with a diameter of 10-40 mm or steel wire;

- when strengthening dams enclosing ponds, the screen covers the entire body of the dam, and the depth of the injectors is the sum of the height of the dam, the depth of the pond and 100-200 cm below the bottom of the pond;

- the screen is made of two-row, or three-row, or continuous over the entire area of the reinforced water-saturated soil, and its depth exceeds the depth of the water-saturated soil by 100-150 cm;

- in one well there are several injectors of various heights, designed for cementation of different layers of soil, and the perforated part of each subsequent injector is located below the perforated part of the previous one, without blocking it;

- wells drilled vertically and / or obliquely, or by beam divergence;

- each injector is fixed in the well by a packer, which can be both superficial and deep;

- the injection solution injected into the injectors contains at least 30% cement, 70% clay and bentonite, or part of the clay is replaced by fine sand, in addition, the solution may contain liquid sodium or potassium glass at a rate of 3-5 kg per 1 cubic meter solution;

- the perforated part of the injector does not exceed 10-12 m.

The essence of the utility model is illustrated by drawings, which show the claimed anti-filter screen:

figure 1 is a diagram of the location of the injectors of the anti-filter screen, intended for enclosing the dam body of water, in the thickness of the dam body;

figure 2 - arrangement of injectors with its three-row execution, top view.

The anti-filter screen (Fig. 1 and Fig. 2) contains non-removable metal injectors 1. Position 2 denotes the body of the dam, position 3 denotes a reinforced cement-cemented massif, position 4 denotes the bottom of the reservoir.

The construction of the anti-filter screen is as follows.

At the first stage, marking of future wells for drilling and subsequent driving of injectors into them is carried out 1. The marking is carried out according to the natural topography or along the already built dam (in the case of a screen in the dam body), starting with the extreme injector attached to the project by a specific point (edge dams, pit board). The mesh or distance between the injectors is determined taking into account the filtration coefficient in the soil. The higher the filtration coefficient, the smaller the distance between the injectors. For example, soils at the facility indicated in table No. 1 under No. 1 have a filtration coefficient equal to 0.55 m \ day. These soils are classified as highly permeable. The distance along the grid between the injectors in this case is minimal from 1 × 1 m to 2 × 2 m. The soils at the object indicated in the table under No. 2 have a filtration coefficient of 0.08 m / day. These soils are included in the category of permeable. The distance along the grid between the injectors in this case is from 2 × 2 m to 3 × 3 m.

After driving all the injectors 1, if the work is carried out on a slope or on the crumbling surface of the dam, they are strapped with round steel or steel wire (not shown) at the mark of the day surface. The binding is made by welding the edges of round steel with the body of the injector 1.

Then, an injection solution is injected into the injectors 1, which contains at least 30% cement, 70% clay and water. Part of the clay clay can be replaced with fine sand. Sodium or potassium liquid glass of 3-5 kg per 1 cubic meter of solution can also be added to the solution to reduce the formation time of the technogenic array.

When installing a three-row and continuous anti-filter screen, the injection solution is first injected through the injectors of the outermost rows or the first and third row injectors (with a three-row curtain), or the first row of injectors located along the contour of the reinforced array (if the screen is continuous throughout the bottom area of the pit), and the injection solution is prepared in a more viscous consistency with the use of quick-hardening additives, which allows you to create a screen that prevents the injection solution from breaking outside the cemented area, and gives tangible savings on consumables.

When two or three injectors are installed in one well, intended for alternately cementing two or three zones at different depths, the perforated part of each of them is located below the perforated part of the previous one, without blocking it. In this case, when installing two injectors, the second injector will have a blind part equal to the perforated part of the first injector, and when installing the third injector, the height of its blind part will be the sum of the heights of the perforated parts of the first and second injector for accurate spreading of the injection solution in each of the reinforcement zones ( cementation) in depth. For example, 2 injectors located on the dam body at one injection point will be as follows: the first injector has a blind part of 1 m, the perforated part is 7 meters from the mark 0.00 (absolute zero) 0-8 m, then the second injector with a length of 14 m will have a blind part 8 meters from 0-8 m and the perforated part 6 m from -8 to -14 m from the mark of 0.00. If there are two or three injectors at one injection point, the cementation of the soil zones in depth is carried out in a stepwise descending or ascending way (from a shorter injector to a longer one or vice versa).

The number of rows of installed injectors should not be less than 2. Injectors in rows are staggered.

Soil strengthening is carried out under the load created by overlying natural soils, the body of the structure or a special plate. Weight, deformation properties, bearing capacity and permeability of the loading layer should ensure cementation at the design pressure of the mortar without violating the continuity of the loading layer and without leakage of cement mortar to the surface or to the loading layer. Cementation is carried out under a working pressure of 5-15 atm.

The procedure and conditions for carrying out cementation work to create an anti-filter screen are different depending on the properties of the soils and the tasks set. For example, injection of solutions in fractured rocky and karst soils, where the task is to lower the filtration coefficient to reduce the risk of soaking soluble soils, and which leads to the spread of the karst-forming process, injection of the injection solution is carried out in one zone, immediately to the entire depth of cementation. The size of the zone is set by the project.

The injection of the injection solution through the remaining injectors with the device of 3 row and continuous screens and through all the design injectors with the device of 2 row screens is carried out by a gradual approximation, starting with the maximum distances between the injectors at which there is practically no hydraulic connection between them when injecting the solution. In case of complication with the injection of the design quantity of solutions, the injection solution is fed into the cementation zone through each injector in stages, creating a layered soil-cement compound in the cementation zone. After introducing 1/3 of the design quantity of solutions, the well is washed and poured with clay-bentonite solution, shut off with a ball valve installed on each injector. They defend in this position for a day, after which the work on introducing the remaining amount of the solution through the well into the soil is resumed. As a result, a soil-cement reinforced massif 3 is formed.

At the end of the cementation work, the aboveground part of the injector is cut off and filled with a cement plug.

The utility model is illustrated in tables 1-3, which show examples of the application of the proposed technical solution for specific objects (3 objects).

Table 1. Property Number Type of soil at the place of work, features Purpose of work The composition of the solutions used additives one Soils are highly permeable, open karst cavities, marl, mudstone, sandstone, karst-suffusion process Lowering the filtration properties of soils at the base of pile foundations in order to localize the karst process Cement, water, clay-bentonite, fine sand. 2 Bulk soils, loams, fluid clay. Lowering the filtration properties of soils to prevent underflooding of the pit for new construction. Cement, water, clay-bentonite, sodium liquid glass 3 Bulk soils constituent of which are clay, coarse sand Lowering the filtration properties of soils in the body of a dam enclosing a reservoir Cement, water, clay-bentonite, potassium water glass Table 2. Characteristics of the filtration properties of soils before the installation of an anti-filter screen Property Number Deformation Module, Mna specific grip, Mna filtration coefficient, ms porosity coefficient angle of internal friction, degrees natural humidity, d, units plasticity number, d, units flow indicators, d, units tight s / cm3 one fifteen 0.024 0.55 0.78-0.087 19 1.8

2 9 0,03 0.08 eighteen 1.89 3 13 0,03 0.1 16 0.17 0.01 1.9 Table 3. Property Number Physico-mechanical properties of soils after the installation of an anti-filter screen deformation modulus, MPa specific adhesion, MPa filtration coefficient, ms porosity coefficient angle of internal friction, degrees density, g / cm3 one 25 0,038 0.008 22 2.2 2 twenty 0.06 0.01 24 2.25 3 22 0.05 0.001 21 2,3

As a result of the application of the utility model in the treated soil, a reinforced technogenic array is created with low filtration properties and increased bearing capacity. The created technogenic massif consists of natural soils, inclusions of cement stone, other components introduced into the soil and non-recoverable steel injectors, which are a vertical element of reinforcing the technogenic massif. The man-made array, along with high load-bearing capacity, has a virtually waterproof structure. The anti-filter screen replaces the costly anti-filter structures performed in other ways. Soil properties are changed in accordance with table 3.

Work on the installation of an anti-filter screen is environmentally friendly, equipment for the production of work does not carry out harmful emissions into the atmosphere, since it works from electric power supplies. Production is almost waste-free.

The construction of an anti-filter screen is possible on almost all types of soils: rocky and semi-rocky at the base of buildings and structures, including in the slopes of foundation pits, karsted, incoherent (sand, gravel, gravel), bulk and subsidence.

Thus, the use of a utility model can increase the efficiency and expand the scope of the anti-filter screen, simplify and reduce the cost of work on its creation.

Claims (9)

1. The anti-filter screen, made in the form of a single soil-cement reinforced array, consisting of metal, non-recoverable injectors in the form of pipes with a diameter of 32-92 mm, which have blind and perforated parts, driven into pre-drilled wells located in staggered order in several rows, and an injection of clay-bentonite-cement or cement-sand mortar was introduced through the injectors into the soil under the load, and the distance between the injectors is inversely related to the filter coefficient ation saturated soil at the job site. 2. The anti-filter screen according to claim 1, characterized in that when working on the slopes, all injectors are tied by welding at ground level with round steel with a diameter of 10-40 mm or steel wire. 3. The antifiltration screen according to claim 1, characterized in that when strengthening the dams enclosing the reservoirs, the screen occupies an area over the entire body of the dam, and the installation depth of the injectors is the sum of the height of the dam, the depth of the reservoir and 100-200 cm below the bottom of the reservoir. 4. The anti-filter screen according to claim 1, characterized in that it is made double-row, or three-row, or continuous over the entire area of the reinforced water-saturated soil, and its depth exceeds the depth of the water-saturated soil by 100-150 cm 5. The antifiltration screen according to claim 1, characterized in that several injectors of different heights are arranged in one well, intended for cementing layers of soil different in depth, and the perforated part of each subsequent injector is located below the perforated part of the previous one, without blocking it. 6. The anti-filter screen according to claim 1, characterized in that the wells are drilled vertically and / or obliquely, or beam divergence. 7. The anti-filter screen according to claim 1, characterized in that each injector is fixed in the well by a packer, which can be either surface or deep. 8. The anti-filter screen according to claim 1, characterized in that the injection solution injected into the injectors contains at least 30% cement, 70% clay and bentonite, or part of the clay is replaced by fine sand, in addition, the solution may contain liquid sodium or potash glass at the rate of 3-5 kg per 1 cubic meter of solution. 9. The anti-filter screen according to claim 1, characterized in that the perforated part of the injector does not exceed 10-12 m

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