RU2412303C2 - Method to erect tubular drain - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method to erect tubular drain includes making receiving part from flexible mats made of meshy shells and draining filler, which is made of tight rows of light fascines wrapped into geogrid. Flexible mats are arranged around drained perforated pipes normally to direction of filtration flow. At the distance of mats length, additionally around drained pipes, stiffening rings are arranged with height of rib that equals thickness of water receiving part, around which gabion net is tightened along whole area, and fixed to stiffening rings. Draining part is made of similar mats, but arranged at certain distance from each other in direction of filtration flow and with inclination from drained pipes to foot of downward slope. Light fascines are made of dry ripe cane.

EFFECT: reduced labour intensiveness of drainage arrangement and increased efficiency of its operation.

5 dwg

Description

The invention relates to hydraulic engineering and can be used as a drainage device for earthen dams and dams.

The closest technical solution is the tubular drainage of earthen dams and dams [1], made of perforated concrete or asbestos-cement pipes laid with a slope parallel to the bottom of the slope and sprinkled with a reverse filter. The main disadvantages of this technical solution are:

- the need for a large amount of stone and sand-gravel material;

- the complexity of the work of laying inverse filters around the pipe;

- low work efficiency.

The purpose of the invention is to increase work efficiency and reduce the complexity of construction.

This goal is achieved by the fact that in the method of erecting tubular drainage of earthworks, consisting of perforated drainage pipes, receiving and discharge parts, the receiving part is made of flexible mattresses consisting of mesh shells and a drainage aggregate, which is made of dense rows of light fascia wrapped in a geogrid, and flexible mattresses are laid around perforated drainage pipes normally to the direction of the filtration flow, while at a distance of the length of the mattresses additionally around the catchment stiffening rings are arranged with stiffeners with a rib height equal to the thickness of the water-receiving part, and along its circumference over the entire area they tighten the gabion net and attach it to the stiffening rings, and the discharge part is made of similar mattresses, but located at a certain distance from each other in the direction of the filtration flow and with a slope from the drainage pipes to the bottom of the bottom slope.

In figure 1. shows a cross section of an earthen dam (or dam) with tubular drainage; figure 2 is a plan of a horizontal section of the drainage made along the axis of the intake pipe; figure 3 - perforated pipe with rings (ribs) of rigidity in a perspective view; figure 4 is a light fascin of dry reeds; figure 5 is a flexible mattress of light fascia, wrapped in a geogrid.

Tubular drainage consists of perforated drainage pipes 1 with stiffening rings 2; water intake part 3, which is a flexible mattress 4, consisting of light fascia, wrapped in a geogrid and laid around pipes 1 normally to the direction of the filtration stream 5; mesh shell 6 arranged (with tension) around the circumference around the water intake part 3 and attached to the rings (ribs) of rigidity 2; and the drainage part 7, consisting of similar mattresses 4, but laid in the direction of the filtration stream 5 and located at a distance from each other with a slope from the catchment pipes 1 to the bottom of the bottom slope.

The method of erection of tubular drainage is carried out and works as follows.

During the period of construction (reconstruction) of an earthen dam (or dam) at the base of the lower slope, just above the bottom of the NB, a trench is developed for the overall dimensions of the drainage. A net shell 6 (gabion net) is laid along the bottom of the trench, on top of which perforated pipes 1 with stiffening rings 2 are laid, between which flexible mattresses 4 are tightly laid, starting from the base of the pipes 1 to their top. Around the water intake part 3 (from flexible mattresses 4), the mesh shell 6 is tightly tightened around the circumference and attached to stiffening rings (ribs) 2 made of polymeric materials. Further, from the drainage perforated pipes 1 at a certain distance from each other and with a slope towards the downstream (NB), trenches 1-2 meters wide are filled with flexible mattresses 4, forming a drainage part 7 of the drainage, the thickness of the mattress is 0.3-0 , 5 m. After that, on top of the collected drainage complex, they erect (finish) the lower slope of the earthen structure (dam or dam). In this case, the width of the drainage mattress trenches and the distance between them are taken depending on the maximum possible flow rate of the filtration stream. The mattress trench with a width of 1 m and a thickness of 0.3 m, which runs with a slope of 0.05, allows water flow up to 50 l / s. At the same time, it is also necessary to observe the basic condition for the normal operation of tubular drainage: the maximum possible water level in the sewage system must always be below the mark of the bottom of the drainage pipe 1, i.e. there should not be a backwater level on the part of the National Bank.

Tubular drainage works as follows. Filtration water, moving under the influence of hydrostatic pressure from the upstream side (WB) through the pores of the soil body of the dam or dam, falls into the zone of the water intake part 3 of the drainage. Further, flexible mattresses 4 freely accept water because of their high water permeability and pass through slotted holes into the drainage (catchment) pipe 1. And when filling pipe 1 to the middle of its section, water easily flows from pipe 1 to the drainage part 7 - to the mattress discharge trenches , which acceleratedly remove filtered water to the NB due to the good slope and gradient of the filtration flow. In the absence of water level in the NB, more efficient drainage is ensured. Therefore, the proposed design drainage is recommended to be used in medium and low-pressure soil dams and dams of land debris, when there is no water in the NB under normal operating conditions, or when there is a small level of water in the NB that cannot affect the drainage operation mode. The main soil load above the perforated drainage pipes 1 is perceived by stiffening rings 2 and the mesh shell 6. Therefore, flexible mattresses 4 of the water intake part 3 will always work under normal conditions and the reception of filtration water will be provided quite reliably. Above the drainage part 7, also consisting of flexible mattresses 4, there is a small layer of soil, which does not significantly affect their throughput. The efficiency of drainage mattresses increases if sandy or sandy-gravel soil is laid on top of them.

In the manufacture of drainage, the main filtration material uses dry reeds - a fairly stable and durable natural material that works effectively in an aqueous environment and is a highly draining material. Light fascines wrapped in a geogrid, forming a water intake part 3, prevent filtration deformation of adjacent soils. This eliminates the removal and penetration of small particles of soil into flexible mattresses 4, due to the use of the geogrid for wrapping light fascines in mattresses. Thus, safe reception and removal of filtered water through the body of earthworks is ensured at all possible operational water levels in the WB.

Tubular drainage, erected by the proposed method, can work effectively without major repairs for 15-20 years. Due to the fact that dry ripened reeds are highly draining and fairly resistant material, which is able to stay in the aquatic environment for up to 20 years or more. The service life of dry reeds used for the manufacture of light fascia and mattresses can be extended twice if it is treated with a special solution that increases the water resistance of the material.

The invention is recommended to be used on the flat sections of rivers during the construction and reconstruction of earthen dams and dams of landsliding areas where there are not enough stone and gravel materials. And also - in hard-to-reach places where the delivery of construction equipment is difficult.

The source of information

1. Waterworks. Designer reference. / Under the general editorship of Dr. tech. sciences, prof. V.P. Nedrigi. - M.: Stroyizdat, 1983, p. 171-173, p. 491.

Claims (1)

A method of erecting a tubular drainage of earthworks, consisting of perforated drainage pipes, a receiving and a discharge part, characterized in that the receiving part is made of flexible mattresses consisting of mesh shells and a drainage aggregate, which is made of dense rows of light fascines wrapped in a geogrid, flexible mattresses are laid around perforated drainage pipes normally to the direction of the filtration flow, while at a distance of the length of the mattresses additionally around the drainage pipes stiffening rings are formed with a rib height equal to the thickness of the water receiving part, and a gabion net is pulled along its circumference over the entire area and attached to the stiffening rings, and the outlet part is made of similar mattresses, but located at a certain distance from each other in the direction of the filtration flow and with a slope from the drainage pipes to the bottom of the bottom slope.

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