SU1661267A1 - Antiseepage diaphragm of earth dam and method of its construction - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to hydraulic engineering. The purpose of the invention is to increase the anti-filtration reliability of the diaphragm by reducing the length of the joints between the wall elements and making them waterproof and by lengthening the curvature of the flow lines of the filtering water through the diaphragm while accelerating the pace of erection and reducing its cost. The impervious diaphragm includes a vertically positioned layer of asphalt concrete 1 enclosed between walls 2 and 3 formed by panels 4. Panels 4 are installed so that horizontal and vertical joints formed in one wall are offset from the rectangular projection onto this wall between the panels 4 in another wall. In each panel 4, along its perimeter, from the side of the layer of asphalt concrete 1, there are bevels that form grooves running along the horizontal joints and grooves running along the vertical joints. Horizontal seams are filled with a layer of asphalt. The construction of the diaphragm is carried out with the building of concrete panels 4 each other alternately ahead of each other, each time alternately and each time the wall half exceeds the height of panel 4. After each next floor panel is installed, panel 4 is filled with asphalt concrete 1 by walls. 2 sec. and 5 hp ff, 6 ill.

Description

FIELD OF THE INVENTION The invention relates to hydraulic construction and relates to anti-seepage devices for earth dams.

The purpose of the invention is to increase the antifiltration reliability of the diaphragm by reducing the length of the joints between the wall elements and making them waterproof and by lengthening the curvature of the flow lines of the filtering water through the diaphragm while simultaneously accelerating the diaphragm's construction and reducing its cost.

Figure 1 shows the diaphragm of a dirt dam, a cross section; figure 2 is a view of And figure 1; on fig.Z - the node in figure 1; figure 4 - section bb in figure 2; 5 shows a diaphragm of a soil dam during the erection period, a cross section; figure 6 - node II in figure 2.

The impervious diaphragm includes a vertically located layer of asphalt concrete 1, enclosed between walls 2 and 3, formed by panels 4 (Fig. 2). The panels 4 are installed so that the horizontal joints 5 formed by them and the vertical joints 6 in one wall are displaced relative to the rectangular projection on this wall of the joints between the panels in the other wall (the projection of the seams in Figure 2 is shown by a dotted line). In each panel 4, along its perimeter from the side of the layer of asphalt concrete 1, bevels 7 (FIG. 3) and bevels 8 (FIG. 4) are made, which form grooves 9 running along horizontal joints 5 and grooves 10 running along vertical joints 6.

The depth a of the groove 9 is 0.5-0.7 thickness g of the panel 4, and the depth b of the groove 10 is 0.8-0.9 thickness d of the panel 4,

Horizontal seams 5 are filled with asphalt layer 11 (FIG. 3), the thickness h of which, depending on the compressibility in the vertical direction of the soil layers adjacent to the diaphragm, is usually taken equal to

h (0.01-0.03). H, where H is the height of the panel.

The outer surfaces of walls 2 and 3 are coated with antifriction lubricant in the form of a bitumen coating or in the form of two layers of a polymer film with antifriction lubricant between them (the lubricant is not shown in the drawings).

The displacement of vertical joints between panels in adjacent rus of one wall and the displacement of these joints relative to vertical joints between panels in opposite rus of a wall is carried out by the value

,

where I is the length of the panel.

With such an offset, the shortest distance from between a vertical seam in one wall and the nearest vertical seam in another wall will be the same everywhere, the maximum possible and equal to

ten

.L |:

R | 2

91

five

0

five

0

five

0

five

0

five

where z is the thickness of the asphalt layer.

The diaphragm is erected simultaneously with the transition layers 12 of the dam and its side prisms 13.

The construction of the diaphragm is carried out with the building of concrete panels ahead of each other by installing the concrete panels with coats alternately and each time with the excess of the opposing wall half the height of the panel. After installing each successive panel of rushes into one of the walls, asphalt concrete 1 is filled with the space between the walls to a height equal to half the height of panel N.

At the base of each panel being installed, a layer 11 is laid on asphalt tape, the guide pairs 14 (Fig. 2) of the panel are fixed to the underlying wall, and the temporary connections 15 (Fig. 5) of the panel are attached to the fixed part of the dam panel of the opposing wall.

Filling the space between walls 2 and 3 with asphalt concrete 1 is carried out by layers and offset from each other by horizontal technological joints 16 (FIG. 3) between the layers of asphalt concrete and horizontal joints 5 between panels 4.

Each guide pair 14 consists of a rod 17 protruding from the overlying panel 4 and a cavity-forming element 18 located in the underlying panel. The rods 17 and the elements 18 may be fixed on the outer edges of the panels 4 by means of the fixing plates 19 and 20 (Fig 6) or may be recessed in the panel 4 (the execution of the guide pair recessed in the drawings is not shown). In the latter case, immediately before installing the panel 4, the cavity of the guide pair is filled with hardening mastic.

The thickness d of slept soil layers 21 and 22 (figure 5) is prescribed in accordance with condition H

d j

where n is an integer, usually 1 or 2 or 3,

The diaphragm works as follows.

Under pressure, water from the upstream filters through the asphalt concrete 1 through the layer of asphalt 1 mainly through interlayer seams 16. When entering the asphalt 1 layer and leaving it, the water overcomes an obstacle in the form of high-quality concrete (reinforced concrete) walls 2 and 3 along the most permeable places that are usually the seams between the panels. However, as a result of displacing the seams in one wall relative to the seams in the other wall, the probable water flow lines are significantly lengthened, which increases the water tightness of the diaphragm.

During deformations in the body of the dam, the panels 4 are moved along the outer surface of the layer of asphalt concrete 1. In this case, the asphalt layers 11 are partially extruded from the horizontal joints 5, and the sharp edges of the panel in the vertical joints 6 may be exposed to smthy.

The presence of antifriction lubricant on the outer surface of walls 2 and 3 ensures that the soil slides along the diaphragm, without creating additional compressive stresses in the diaphragm1.

Claims (7)

Claims 1. An impervious diaphragm of an earth dam comprising a vertically positioned layer of asphalt concrete sandwiched between two walls formed by mounting wall elements on top of each other, in order to increase the anti-filtration reliability of the diaphragm by reducing the length of the seams between the elements walls and making them waterproof and by lengthening the curvature of the current lines filtering water through the diaphragm while simultaneously accelerating the pace of erection s and a reduction of its cost, wall elements are in the form of concrete panels installed with offset joints between panels in one wall with respect to the rectangular projection on the wall joints between panels in one wall with respect to the rectangular projection on the wall the joints between the panels in the other wall, and in the panels along their perimeter, from the side of the asphalt concrete layer, are made bevels. 2, Aperture according to claim 1, characterized by because the horizontal joints between the panels are filled with a layer of asphalt, the thickness h of which satisfies the condition  h (0.01-0.03) H ,, where H is the height of the panel. 3. The diaphragm according to claim 1, characterized in that the outer surface of the diaphragm is coated with antifriction lubricant. 4. The diaphragm according to claim 1, about tl and h and y and a with the fact that the offset of the vertical seams between the panels in adjacent rus of one with if genes, these seams are displaced relative to the vertical seams between panels in opposite rus of the other wall by the amount and -3 I where I is the length of the panel. 5. The method of construction of the impervious diaphragm of the earth dam, including the buildup of two opposing walls by installing the elements of the walls of Rus with each other and layer-by-layer filling the spaces between the walls with asphalt concrete, characterized in that elements of the walls are made in the form of panels, and building up the walls with Rusas is carried out alternately and each time the panel exceeds the height of the opposing wall by half the panel height, and filling the space between the walls with asphalt concrete after the installation of each next floor of the panels in one of the walls. 6. A method according to claim 4, characterized in that when the walls are expanded, the panels of the rus being installed are mounted with guide pairs on the panels of the lower rus and temporary horizontal connections to the panels of the opposing wall. 7. The method according to claim 4, characterized in that the filling of the space between the walls with asphalt concrete is carried out with displacement relative to each other of the horizontal process joints between layers of asphalt concrete and seams between the panels. j. l-i- i .L- Hyi-h j - "- i - - . „ Taf-pp1 % 1J. V myth J 1931981 FIG. 3 Bb " . - V-: X; : -:;: - Vl -. X .. ;; -: .. v-- -v -; : ; 9 - :: V: Vtt fe FIG. 4tt