RU2539447C2 - Method for horizontal draining of waterlogged structures on pile foundations - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method for horizontal draining of waterlogged structures on pile foundations relates to construction, namely to the construction of drainage systems for the protection of structures on pile foundations against ground water logging. As per the proposed method, dewatering of a waterlogged object is achieved due to the fact that from one radial drain well developed along the outer wall outside the structure normally to rows of the load-carrying piles and equipped with a filter there passed are additional side drain wells between the rows of piles. Drilling of additional shafts is performed by means of a downhole motor and diverting devices out of the above said radial well. The steadiness of walls of the additional wells at drilling is provided by the application of hydrolysed polyacrylonitrile or other self-decomposed drill fluids. After driving of the side additional shafts is completed, the drill tool is disconnected and used for the shutoff of the well bottom, and the motor together with drill pipes is removed through a filter pipe that was drawn by means of the downhole motor.

EFFECT: proposed drainage system allows solving a problem of protection against waterlogging of structures on pile foundations.

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Description

The invention relates to the field of industrial and civil engineering and is intended to drain flooded objects.

From the current technical level, a method is known that is used at the stage of construction of an object in flooded areas, a method of horizontal tubular drains, which includes laying in trenches constructed along the perimeter of the protected object, drainage pipes with filtering dusting. Drainage pipes (asbestos-cement, ceramic, made of porous concrete, etc.) are placed below the bottom of the foundation of the structure [Bolotskikh N.S., Ponomarenko Yu.V. and other Handbook on drainage of rocks. M .: "Nedra", 1984, p.184-186]. At the stage of operation of facilities, the method of radiation drainage is widely used, the use of which is most effective in conditions of high building density and the development of a dense network of underground utilities. The specified method usually includes sinking two vertical shafts at the diagonal corners of the flooded hull, sinking from the shafts of horizontal beam drainage wells under the protected object (s), as shown in Fig. 1. Full-length beam wells are equipped with filters that receive groundwater and discharge them into a catchment located in the buried part of the trunks, after which water is pumped to the surface into the drainage system [Ponomarenko Yu.V., Anpilov V.E. Radiation drainage of built-up areas. M .: "Nedra", 1989, p.22-23].

The described method of radiation drainage, as the closest in the aggregate of essential features to the proposed, is selected as the closest analogue.

The disadvantages of the known method of protection against flooding are the diverging position of the beam wells away from the trunk and, therefore, incomplete drainage of the parts of the protected object removed from the trunk. For this reason, it becomes necessary to construct a second radiation drainage (Fig. 1). It is known that the penetration of the trunk is the most expensive element of radiation drainage, this leads to a significant increase in capital costs.

The second significant drawback of these methods of radiation drainage associated with the widespread use of currently pile foundations. Pile fields are an insurmountable obstacle for constructing beam drainage wells under structures protected from flooding, and tubular drains being built from the outside of the facility are not sufficiently effective.

The objective of the invention is to expand the functionality and increase the technical efficiency of the method of drainage of flooded objects and reduce the cost of the system for protecting objects from flooding.

Technical results that are obtained when implementing the proposed method of drainage are:

- increase in efficiency and a more even (in area) decrease in groundwater levels;

- the possibility of using drains to protect against flooding of objects on pile foundations;

- reduction of capital costs for the construction of a drainage system.

The claimed method is illustrated in figure 2.

Figure 2 shows:

1 - shaft shaft of horizontal horizontal drainage;

2 and 3 - beam drainage wells;

4 - lateral trunks of horizontal drainage wells.

An inventive step of the claimed method is the construction of a system of horizontal drainage wells under the grillage of a flooded object between the rows of load-bearing piles constructed from a beam well, which makes it possible to drain the object on a pile foundation and refuse to dig a second shaft shaft.

The claimed method is carried out as follows: at one of the corners of the protected object, where the groundwater level is at the highest elevations, lay the mine shaft 1 (figure 2) to a depth exceeding the level of the sole of the object grillage, which is necessary to place the mouths of the beam wells and drainage water reservoir. The depth of the ray wells and the volume of the catchment are determined when designing the results of filtration calculations to lower the groundwater level within the boundaries of the area of the object and the expected water inflows.

Since the soils at the base of the object are flooded and are in an unstable state, beam wells 2 and 3 are drilled with simultaneous fastening by a column of protective pipes (not shown in Fig.). If the drilling of beam wells is envisaged to be performed by the ULB-130 installation, then the diameter of the barrel should be taken 3.6 m in the light. Beam wells are equipped with full-length filters selected taking into account the particle size distribution of flooded soils. The wellheads are equipped with gate valves (not shown in FIG.).

In the proposed method of drainage, beam wells are laid on the outside of the object parallel to the external walls, one of which is placed normally to the rows of bearing piles. Then, from this beam well 3 from points A, B, C, D, E, F, lateral additional horizontal drainage wells No. 4, 5, 6, 7, 8, 9, parallel to each other and directed under the protected object, pass. The drilling points of the lateral additional horizontal drainage wells are set taking into account the radius of rotation (curvature) of the wells required for the downhole motor used and the penetration of wells in the required direction between the rows of piles. Typically, the radii of curvature under these conditions are in the range of 30-50 m.

The penetration of lateral additional horizontal drainage wells is started from the horizontal end well 4, then the lateral additional horizontal drainage wells 5, 6, 7, 8 and 9 are alternately constructed. The number of lateral wells may vary in accordance with the size of the object.

Lateral additional horizontal drainage wells are drilled with an outlet of at least 5 m beyond the grillage of the protected building, which is required to achieve the necessary lowering of the groundwater level on the outer edge of the grillage.

The lateral additional horizontal drainage wells 4 during the drilling process are equipped with flexible filters that extend beyond the downhole motor (not shown in FIG. 2). To do this, to the downhole motor using an easily released adapter (not shown in FIG. 2), a filter column running next, the inner diameter of which exceeds the outer diameter of the downhole motor, is connected. The diameter of the rock cutting tool connected to the engine, also easily detachable sub, must exceed the diameter of the filter drawn into the well. The latter allows, after reaching a predetermined length of the sidetrack, to free the engine and remove it together with the drill pipes from the well through the filter string.

The stability of the walls of the wells during drilling is ensured by the use of flushing fluids based on self-dissolving or hypane solutions.

Well bending and transition to sidetracking are carried out using a downhole motor and deflecting devices: OTC, P-1, etc.

After the completion of the sidetracking, the drilling tool is disconnected from the engine, it blocks the bottom of the sidetrack and remains in the rock mass.

The practical applicability of the proposed system of horizontal drainage wells is shown by the example of a flooded enrichment case.

Example. The natural base of the body is sandy loam with a filtration coefficient of 1.7 m / day. The depth of the foundations is 5.8 m. The dimensions of the hull in terms of 80 × 30 m.

In contrast to the closest analogue, the protection against flooding by the proposed method is carried out by a method that includes the sinking of one shaft shaft (1), 2 beam wells (2, 3) and three lateral additional horizontal drainage wells (4, 5, 6), as shown figure 3. The operation of the constructed system of drainage wells with their simultaneous operation allowed to reduce the groundwater level by the necessary 1.7 m for 67 days.

Claims (1)

A method of horizontal drainage of flooded structures on pile foundations, including driving a shaft shaft from the outside of the object and drilling beam wells parallel to the external walls of the protected object, characterized in that the beam wells are located normally to the rows of bearing piles using a downhole motor and directional deviations of the drilling pass additional lateral drainage wells directed under the grill of the structure between the rows of piles, additional lateral drainage wells lead outside the object boundaries not less than 5 m; when drilling with a downhole motor, filter columns from flexible filters are pulled into additional lateral drainage wells, the stability of the walls of the beam and additional lateral drainage wells is achieved through the use of gypsum or other self-dissolving drilling fluids, after completing the drilling of additional lateral drainage wells, the disconnected drilling tool is used to overlap the bottom of the additional lateral drainage well and left in the soil mass, and the downhole motor together drillpipe The filter is recovered through the column.

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