US2138071A - Dam - Google Patents

Description

Nov. 29, 1938. E. H. PARKINSON ET AL 2,138,071

v DAM Filed Nov. 24, 1936 2 Sheets-Sheet 1 l I l Fig. 2.

THoMHs Enwnsw RDN ER Wmomzm Tusoo BY? 5 i 47' 7' GA /V5 Nov. 29, 1938. E. H. PARK'INSON ET AL 2,138,071

DAM

Filed Nov. 24, 1936 2 Sheets-Sheet 2 Enema Hqnmsou PHRHINsoN Tuomns Eownao GFmoNsR Wvnonqm THEODORE VINT Patented Nov. 29, 1938 PATENT "OFFICE- D'AM Edgar Harrison Parkinson, Thomas Edward Gardner, and Wyndham Theodore Vint, Bradford, England Application November 24, 1936, Serial No. 112,487

In-GreatBritain December 3, 1935 6 Claims.

This invention. relatesrto improvements in dams, walls of reservoirs, and the like formed of concrete ferro-concrete or other suitable materials, and is particularly adaptable for thin wall construction with a view'to elimination of all instability with increased margin of safety and at much reduced constructional and maintenance cost.

The invention is'a reservoir or dam construction in the form of awall of L-shaped vertical section made up of 021601 a series of units. In the latter case the units are conneotable. The foot of the unit or units projects a convenient distance into the reservoir and is arranged to have no upward pressureon its underside, the inner end or edge, i. e. the toe ofthe foot, being turned down and connected to the cut out or impervious strata, which-prevents water from seeping under the foot .of the dam.

The construction is such that the downward pressure of water upon the foot portion .will balance or exceed the'outward' thrust upon the breast portion'of the wall..

Rigid connections between the foot and wall portions are made in theform of buttresses in tension. and will preferably be connected to the down-turned toe portions.

The possibility of upward water pressure on the underside of the foot may :also be avoided by providing a space beneath such foot, to which access may be had from the downstream side of the wall, which serves to drain away any water seeping in and provides inspection for the underside of the foot portion of the .darn.

Where the wall is made up of aseries of units, suitable joints will be provided preferably those of a type'projecting into the water, which will ensure that the lateral pressure of the water acting thereon will close and tighten them.

While the'verticali section of the wall is L- shaped it must be understood that the actual form of wall may vary and may be of hollow rectangular form braced internally and provided with means of access .of water to the interior to enable horizontal water pressure to act. against the vertical downstream part of the wall, and the vertical pressure to act upon the foot portion, all substantially as hereinafter more particularly described.

ther details of construction will also be referred to.

For the better understanding of our invention reference is made to the accompanying drawings in which the same reference characters refer to A the same parts and wherein:

Fig. 1 represents a plan of a portionof a dam arranged in diagrammatic form according to our invention.

Fig. 2 represents a section online ab of Fig. :1.

Fig. 3 represents a section online c+ -dof Fig-1.

Fig. 4 represents a composite elevation of :a dam according to one form of our invention showing upstream and downstream ifaces Ltd the right and left respectively.

Fig. 5 represents a section through'one of the dam wall units.

Fig. 6 represents a composite sectional plan of the parts incorporated in Fig. l. .In this-.flgwe the left hand part shows the"cut 'out"and joint below the 'foot portion on line 12-) .of Fig.4. The central parts is a section on line.gh of Fig. 4 and the left hand section or part is a section on line 11-9 of 'Fig. 4, and

Fig. 7 represents an enlargedisectional'view o'f the joint referred to.

To carry our invention into-effect :and referring to Figs. 1, 2 and 3 of the-drawings in Fig.1, A, A A A and A represents .units :of a-dam, units A, A and A beingshown in vfullilines, the other two in broken lines. Each unit is characterized by a wall .3 and .a foot'orfloorB 'projecting into the reservoir, or upstream. This foot is connected at its toe.B to a cut out C projecting intotheimpervious strata, and between the undersi'de'of such foot and the upper face of the ground is a space D which is freely drained. Each unit .isprovided with two buttresses in the form of webs F, 'one on each side, and each buttress along its inclined waterside edge is=curved toward the adjacent buttress, so that when the units are assembled the 'said curved edges form a joint as indicated at J. This arrangement results in a space S being provided between each unit and its .next adjoining unit on each side, such space being closed to the passage of water on the waterside at the joint. J, but open on the downstream side of the device.

From' the general arrangement before described it will be understood and clearly seen that a great advantage over prevailing systems is gained as the forces exerted by the water are used to effect its own support, thus making it unnecessary to amass great quantities of material to secure that end.

The meeting faces of the web members preferably will be provided with'a suitable sealing material such as asphalt and the curves at the joints J will be such as to ensure that the lateral pressure of the water acting thereon will close and tighten such joints. The projections of the foot of the dam under the water will be such as to secure a load adequate to ofiset, through the medium of the connecting webs or buttresses, the outward thrust upon the dam.

For shallow dams we propose that units of a size and weight suitable for road transport be made for stock at a works specially equipped for the purpose, and when ordered conveyed to site, placed in position with their cut outs C let into a clay-puddled or like trench, and bolted together along the line of the joints, which in most cases will be vertical throughout. As the walls of such units would be very thin and the manufacture both rapid and economical, the economy over prevailing systems is obvious even for shallow dams, and the: rapidity of erection determined only by the rate of delivery, will be a great asset.

With regard to each unit it will be understood that the outward thrust is concentrated on the wall B and this thrust is balanced by the downward pressure on the foot B via the buttress members which, in effect, are tension webs.

The lateral pressures upon the projecting webs of the buttresses balance similar pressures on the adjoining units and in so doing tighten the jointsv between the units.

The effects of temperature changes are localized in each unit, and cannot become cumulative. Each unit will, by preference, be cast in one continuous operation in order to avoid junctions formed between castings made at differing dates.

Referring now to Figs. 4, 5, 6 and 7 of the a'ccompanying drawings, wherein we have illustrated a modification in the form of a somewhat massive dam. Here it will be noted that the units are substantially rectangular honeycomb blocks. each with an upstream wall B parallel to a downstream wall B, and from the wallB extend webs F of such curvature that the free edges of the webs of adjacent units form between them vertical open joints J through which access is provided for water from the upstream side. In

f this form the walls are provided with a fioor B,

which is the equivalent of the projecting foot B before described. The sectional plan views of each unit shown in Fig. 6 are taken reading from left to right, on lines e-f, gh, -7 of Fig. 4.

55 Each unit is built up as a hollow honeycomb-like body wherein the numerous walls marked R supplement the webs or buttresses E and are distributed throughout the unit in such a manner as to (1) materially support and stiffen each other (2) to relieve at numerous points the outward thrust upon the wall B, and (3) to pass through the floor B at frequent intervals down to the foundations, and in some cases to the bottom of the cut out thereby distributing the load evenly over the whole area.

The water in the reservoir will at all times have free access to the whole of the inter-connected interstices or chambers in the said honeycomblike unit above the floor B entering them by the way of a series of openings 0 through the waterside wall B and any protective skin or like as hereinafter referred to. This ensures the necessary load for balancing the outward thrust.

It will be understood that where a honeycomblike structure is utilized the interior will receive water from the reservoir, each interior chamber being connected by suitable apertures to one or more adjacent ones and the unit will be filled with water to the reservoir water level. It is preferred that the apertures between the chambers will decrease in size from the water side wall B to the wall B, and that no single chamber shall receive water from more than one connection or opening 0.

The lower portion of each unit is shown in section in the central portion of Fig. 6, and this portion connects-to the cut out C. What may be termed the main body of the unit is erected over this base portion, the floor B separating the two and covering or roofing the lower part. The webs R of the lower part will be formed as continuations with the webs R of the main body of the unit and the re-inforcing rods used in construction with the lower webs will continue upwards and serve the upper webs thereby assisting to secure the continuity desired.

P and P represent protective skins over the work, the skin P being pierced by apertures O to permit water to pass through the skin'and into the hollow wall and to permit water pressure to have access to the flexible webs F forming between them the joints J. This construction is best seen in Fig. 7.

Where the skin P surrounds the webs it is not desired to stay or strengthen the webs by the skin and such skin will consequently be entirely severed or cut through from bottom to top as at D between every two supports for same from the projections F, su'ch severances preferably having overlapping sliding portions.

It is preferred to cover the downstream part of the space S and likewise the top or roof thereof by overlapping lips or projections S to prevent. the entrance of extreme cold or hot air, but such arrangement will not be allowed to interfere in any way with the freedom of movement between adjacent units. Each unit may have one or more cross floors N and a roof N the former being pierced to afford access and relieve trapped air, and to allow the unit to fill with water to water level. The necessary service openings above the overflow level will relieve any tendency for air trappings in the upper portions of the units.

Access to the interior of each unit may be had along a floor or gangway, provided with water tight doors T on. each side of each space S below the Water level, to which doors access may be gained from the space S. Preferably however, a fioor or series of gangways are made above overflow level which will likewise give access to the top of each chamber. These continue across or over spaces S where they are made with overlap- V ping sliding joints to maintain freedom of movement for each unit the whole length of the dam.

In assembling, alternate units will first be erected and when set will have their projecting webs F covered with a suitable layer of mastic asphalt or similar jointing or sealing material as at J Fig. '7. Such webs F are then strained back from their original positions in which they are cast. The intermediate units are then cast with their half portions F of the joint directly against the asphalt referred to. When the intermediate units are set and the backward strain is relieved from the previously cast portions they will spring towards the newly cast parts until the pressure upon the asphalt is equal on both sides of the joint, causing such joint to be reasonably tight even before receiving any lateral pressure from the water. These springy projections will absorb all movement of the concrete without any detectable or permanent results and will cut out the possibility of movement of the various units becoming cumulative.

The said joints are composed of lasting materials and are not subject to disintegration thus completely solving the problem of leak prevention as the forces tending to open the joints are as nothing compared with those available for closing them and squeezing the mastic sealing into any voids that might otherwise permit leakage.

In order to take off or ofiset any undue or excessive strain upon the webs F each web may be provided with one or more ribs F after the manner illustrated in Figs. 6 and 7.

Pairs of doors or lock-gates T, shown in the space S, are attached to opposite buttress members and are adapted to close in the direction of water pressure should any damage occur at the joint J and water leak therethrough as described in our companion specification. Two or more pairs of such doors or lock-gates may be adopted in such space S.

We have described a reservoir construction wherein only one main wall is employed, but the construction may be applied to walls at any angle to each other or upon any curve.

Having thus described our invention we claim:-

1. A dam structure including a downstream vertical Wall, an upstream vertical wall, tension members connecting said walls, and a dam foot extending upstream from the bottom of the downstream wall, said upstream wall having openings therein to permit water to enter the space between said walls thereby to subject the dam foot to downward water pressure between the walls.

2. A dam structure including a downstream vertical wall, an upstream vertical wall, tension members connecting said walls, a dam foot extending upstream from the bottom of the downstream wall, said upstream wall having openings therein to permit water to enter the space between said walls thereby to subject the dam foot to downward water pressure between the walls, and a toe extending downwardly from the forward edge of said foot and imperviously anchored in the geological structure supporting the dam whereby to prevent upward pressure beneath said dam foot.

3. A dam structure including a downstream vertical wall, an upstream vertical wall, tension members connecting said walls, and a dam foot extending upstream from the bottom of the downstream wall, said upstream wall having openings therein to permit water to enter the space between said walls thereby to subject the dam foot to downward water pressure between the walls, said foot having drainage channels at its under side open at their downstream ends and closed at their upstream ends.

a. A dam structure including a downstream vertical wall, an upstream vertical wall, tension members connecting said walls, a dam foot extending upstream from the bottom of the downstream wall, said upstream wall having openings therein to permit water to enter the space between said walls thereby to subject the dam foot to downward water pressure between the walls, said foot having drainage channels at its under side open at their downstream ends and closed at their upstream ends, and a toe extending downwardly from the forward edge of said foot and imperviously anchored in the geological structure supporting the dam whereby to prevent upward pressure beneath said dam foot.

5. A dam consisting of a plurality of sections each having a downstream vertical wall, an upstream vertical wall spaced parallel to the downstream wall and perforated to admit water between said walls, a floor connecting the bottoms of said walls, and side walls rising from the sides of said floor and connecting the side edges of the upstream and downstream walls; said upstream wall having at each side edge a flexible joint portion extending upstream from the wall, and means to secure the upstream edge portions of said joint portions in watertight conjunction.

6. A dam consisting of a plurality of sections each having a downstream vertical wall, an upstream vertical wall spaced parallel to the downstream wall and perforated to admit water between said walls, a floor connecting the bottoms of said walls, and side walls rising from the sides of said floor and connecting the side edges of the upstream and downstream walls; said upstream wall having at each side edge a flexible joint portion extending upstream from the wall, and means to secure the upstream edge portions of said joint portions in watertight conjunction, the pairs of said walls at the adjacent sides of the dam sections being spaced to provide for access to said joints from the downstream side of the dam.

EDGAR HARRISON PARKINSON. THOMAS EDWARD GARDNER. WYNDHAM THEODORE VINT.

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