Thin-wall steel plate dam and construction method thereof

Abstract

The invention discloses a thin-wall steel plate dam and a construction method thereof and belongs to the technical field of municipal water conservancy projects. The dam comprises a thin-wall steel plate, a stand column, an inhaul cable, an anchor seat and a hydraulic membrane. The anchor seat is arranged at the position, higher than the check flood level, of an upstream bank slope of the dam. The stand columns are evenly distributed along the axis of the arc-shaped dam and are oppositely pulled through the inhaul cables and the anchor bases. The tops of the adjacent stand columns are connected with a cable rope. The thin-wall steel plates are welded between the stand columns and curled to form a semicircular cylindrical water retaining dam face. Two sides of the dam body are embedded into rock walls or adjacent dam sections, and the bottom is hermetically connected with the diaphragm wall through the hydraulic membrane. During construction, the anchor bearing is firstly fixed, an anti-seepage system is arranged, a stand column foundation or a raft plate is poured according to geological conditions, after stand columns are installed, inhaul cables and cable ropes are tensioned, steel plates are welded, and a protective layer and a hydraulic film are laid. The structure is thin and light, the modular assembly performance is high, materials are saved by 70%, the construction period is shortened by 50%, the shock resistance is excellent, and the structure adapts to complex geological conditions and is particularly suitable for medium-low water head long dam line projects.

Description

Technical Field

[0001] The present invention belongs to the technical field of municipal water conservancy projects, and specifically relates to a thin-walled steel plate dam and a construction method thereof. The dam is suitable for medium and low head dams, has a thin dam body, and uses very little material. When the dam line is long, the cost and speed advantages are particularly obvious. Background Art

[0002] Traditional dams include gravity dams, arch dams, and steel plate dams. Each of these traditional dams has its own advantages, disadvantages, and limitations when applied in complex geological conditions. Gravity dams require extensive engineering work and a long construction period, and earth-rock dams are difficult to integrate or mix with other dam types. Arch dams have stringent requirements for topographical conditions and construction techniques, and their application is demanding. Currently, commonly used steel plate dams have a monotonous structural design, with a flat retaining surface. Flat plates are extremely inefficient at withstanding water pressure perpendicular to the plate surface, and increasing the plate thickness is costly, limiting their application to low-head projects. Furthermore, steel plate dams also require high foundation anti-slip and anti-seepage properties, making foundation preparation technically challenging and expensive. In existing technologies, lightweight structures are used to simplify construction, such as rubber dams and inflatable dams. However, these structures have weak scour resistance and poor durability, making it difficult to meet the needs of permanent water conservancy projects with high water heads. It is particularly noteworthy that the anti-seepage systems of traditional dams, such as clay core walls, anti-seepage curtains, and anti-seepage walls, all need to be combined with the dam body for joint construction, which takes a long time and will affect each other, making subsequent maintenance and repair very difficult. Summary of the Invention

[0003] The present invention aims to provide a thin-walled steel plate dam and its construction method, which has the characteristics of modular design, strong assembly, good seismic resistance, and convenient construction. It is a dam with fast construction speed, low cost and the ability to flexibly adapt to complex geological conditions.

[0004] A thin-walled steel plate dam, characterized by comprising thin-walled steel plates, columns, cables, anchor seats, and a hydraulic membrane. The anchor seats are arranged on the upstream bank slope of the dam at a position higher than the verified flood level. The columns are evenly arranged along the arc-shaped dam axis with the anchor seats as the center. The columns are steel trusses with continuous closed flat surfaces on both sides of the water-facing surface. The columns are connected to the anchor seats by cables. Adjacent columns are connected top to top with support rods, and scissor braces are installed on the upstream facade; guy ropes are connected at the top of the columns toward the downstream of the dam line; The two ends of the thin-walled steel plate are welded to the flat surface of the adjacent columns. The thin-walled steel plate is curled, and the middle curled section protrudes downstream to form an upright semicircular cylinder with a diameter equal to the distance between the side surfaces of the adjacent columns. The water-facing surface of the columns and the thin-walled steel plate are connected in sequence to form the water retaining dam surface. The thin-walled steel plate retaining dam has columns on both sides or at the ends directly embedded in the rock wall or adjacent dam section; a hydraulic membrane is laid between the lower part of the retaining dam surface and the anti-seepage wall at the top of the anti-seepage curtain, and water-stop joint plates are used at the edges of the hydraulic membrane to seal the upstream dam surface and the anti-seepage wall respectively; a protective layer is set under the hydraulic membrane, hydraulic cloth is laid on steep areas, and fine-grained river sand is laid on flat areas.

[0005] Furthermore, the top ends of all the columns and the bottom ends of the columns fixed on the raft slab are connected to the anchor seats with cables, and the connection points of the cables connected to the bottom ends of the columns are lower than the positions of the water stop plates on the columns.

[0006] Furthermore, when the cable length is greater than 4 times the diameter of the thin-walled steel plate curled section, a segmented arrangement is adopted. The cables merge near the anchor seat and branch near the column. Specifically: The columns are divided into single-cable columns and double-cable columns, and the cables are divided into main cables and auxiliary cables; At least one double-stayed cable column is arranged equidistantly between the single-stayed cable columns; A main cable connected in a straight line to the anchor seat is set on the single-stay column, and two auxiliary cables are set on the double-stay column. The angle between the auxiliary cables and the line connecting the column and the anchor seat is equal to ensure that the direction of the resultant force of the double cables points to the anchor seat; The auxiliary cables are connected to the main cables on both sides respectively. At each bifurcation point of the main cables, auxiliary cables with the same angle as the main cables are branched out to both sides to balance the tension on both sides, or other measures are taken to ensure that the position of the main cables does not shift.

[0007] Furthermore, the portion of the cable below the normal water level covers the floating body.

[0008] Furthermore, when the water depth at the location of the thin-walled steel plate dam is greater than 20m, the columns are vertical layered trusses, each layer is provided with braces and scissors braces, and cables are pulled between the middle of the columns and the anchor seats.

[0009] Furthermore, a waterproof pull rod is used to watertightly connect the cable and the hydraulic membrane at the position where the cable penetrates the hydraulic membrane. The waterproof pull rod is a solid metal rod, and its two ends are respectively connected to the cable. A water stop ring integrated with the waterproof pull rod is provided in the middle of the waterproof pull rod. A hole is opened on the hydraulic membrane, and the waterproof pull rod is inserted into the hole. The outer edge of the hole of the hydraulic membrane is fixed to the water stop ring through a flange and an integrated screw.

[0010] A method for constructing a thin-walled steel plate dam, characterized by comprising the following steps: S1, fix the anchor seat on the rock foundation above the verification flood level on the upstream slope of the right bank of the dam; S2: Arrange an underground anti-seepage system upstream of the thin-walled steel plate dam axis. Set a reinforced concrete anti-seepage wall on top of the anti-seepage system, and embed an anti-seepage water-stop plate on the top of the wall. S3. Excavate the dam foundation, segment it by depth, and trim the cross-section into a stepped shape with vertical slopes on both sides. For the section where the foundation is bedrock, pour a concrete column foundation on the foundation, and directly pour and connect the column on the shore side of the end column with the column foundation as a whole; for the section where the foundation is a stable sediment layer, conduct consolidation grouting and other strengthening treatments to improve the bearing capacity and anti-scouring ability of the base surface. Pour a raft on the foundation as an enlarged foundation for the column. The column is erected on the raft, and limit blocks for restricting the rotation and displacement of the column are arranged on both sides of the column foot. The foundation between the rafts is poured with concrete to the same height as the top surface of the raft at the position below the thin-walled steel plate. S4. Erect scaffolds and scaffolds, and pour and connect the columns to the column foundation or erect them on the raft. S5. Install struts and cross braces, stretch cables and guy wires. Float bodies are covered on the cables located below the normal storage level. After all the cables and guy wires are connected, gradually tighten them symmetrically in a cycle. After the cables are tightened, weld the thin-walled steel plate to the column. The gap between the bottom surface of the thin-walled steel plate and the raft and the foundation is less than 1 cm. Weld a water stop plate at the lower part of the water retaining dam surface. After completion, remove the scaffolds and scaffolds. S6. Lay pebbles with a particle size of 2 - 4 cm at the upstream toe of the water retaining dam surface as a protective layer, and thicken the laying at the corners. Lay a geotextile on the protective layer as an interlayer, lay fine-grained river sand on the geotextile, and lay a geotextile above the fine-grained river sand. S7. Cover the geomembrane, and make a waterproof connection between the geomembrane, the water stop plate and the waterproof tie rod. For the protruding parts in the substructure in contact with the geomembrane, round off the corners or lay a protective layer.

[0011] The beneficial effects of the present invention are as follows: (1) The present invention uses a thin-walled steel plate, cables, columns, etc. to construct the dam body. The load characteristics of the combination of columns with equal diameter and equal depth and the thin-walled steel plate are completely consistent, with the same shape and specifications. The steel plate enclosure, segmented columns and cable anchors have strong assemblability, which is conducive to standardization and sizing, fine design and mass production, and is conducive to modular construction. The dam body is thin, the structure is simple, the components are light and small, which is convenient for the rapid assembly of the dam body and reduces the use of large construction machinery and equipment. Compared with the traditional gravity dam, the material consumption is reduced by more than 70%, and the construction period is shortened by 50%. It is especially suitable for the situation where the dam line is long and there is a lack of dam building materials.

[0012] (2) The arc-shaped dam axis and the semi-circular thin-walled steel plate form a curved flexible anti-deformation structure. The segmented columns are erected in the chute at the top of the raft and form an elastic dynamic stability system with the cables, significantly improving the seismic resistance compared with the traditional rigid dam body.

[0013] (3) Combining the cable segmentation and merging, streamlining the cable layout, reducing the cable usage by 30%, and effectively balancing the self-weight of the cable and reducing the internal stress of the structure through the floating body-assisted horizontal positioning of the cable.

[0014] (4) The foundation of the steel plate dam only has requirements for load-bearing and anti-scouring. The anchor seats, underground impervious bodies, and the foundation of the steel plate dam can be arranged separately, reducing the requirements for the engineering geological conditions of the dam site and the difficulty of foundation treatment, and facilitating the organization of parallel construction to speed up the construction speed. The end of the steel plate dam is a regular vertical narrow section, which is convenient for connecting different dam sections or dam types, flexibly matching, and giving full play to their respective advantages to adapt to complex geological and topographical conditions. The steel plate dam is light in weight, does not require the complete removal of the riverbed alluvium, can greatly reduce the amount of dam foundation excavation, make full use of the original strata and protect the geomorphic ecology, and the materials can be disassembled and recycled easily, meeting the concept of green engineering.

[0015] The construction method of the present invention is flexible, fast, economical, environmentally friendly, and widely used, with great popularization and application value and social and economic benefits. Brief Description of the Drawings

[0016] Figure 1 It is a schematic plan layout diagram of Embodiment 2.

[0017] Figure 2 It is a partial top view schematic diagram of a thin-walled steel plate dam.

[0018] Figure 3 It is a schematic cross-sectional diagram of a thin-walled steel plate dam in the direction of water flow.

[0019] Figure 4 It is a schematic perspective view of the upstream elevation of Embodiment 1.

[0020] Figure 5 A partial perspective view of the upstream elevation.

[0021] Figure 6 It is a connection schematic diagram of the water stop connecting plate and the waterproof tie rod.

[0022] Figure 7 It is a schematic diagram of the waterproof tie rod structure.

[0023] Wherein: 1 - anchor seat, 2 - cable, 21 - floating body, 22 - guy wire, 3 - column, 31 - column foundation, 4 - thin-walled steel plate, 5 - strut, 6 - raft plate, 61 - limit block, 7 - hydraulic membrane, 71 - water stop connecting plate, 72 - hydraulic fabric, 8 - waterproof tie rod, 81 - water stop ring, 82 - integral screw rod, 83 - flange plate, 9 - fine-grained river sand, 10 - pebble, 11 - cut-off wall, 12 - impervious curtain, 13 - impervious base line, 14 - concrete gravity dam, 15 - spillway, 16 - bedrock, 17 - riverbed alluvium, 18 - grouting consolidation body. Specific Embodiments

[0024] Example 1: A wide and shallow river channel features a steep right bank and a relatively gentle left bank. The riverbed is thick with sand and gravel deposits, and the bank slopes on both sides are solid and shallowly buried. A hybrid dam is designed and constructed, with a thin-walled steel plate dam in the main channel and concrete gravity dams on both banks. The dam is generally divided into five sections from right to left: the two central sections, C and D, are thin-walled steel plate dams, while sections A, B, and E are concrete gravity dams 14. Section B is the overflow dam, located on the open left bank. A spillway 15 is located on the dam, and the bank slopes are gentle and stable, providing good conditions for water return to the channel.

[0025] A thin-walled steel plate dam includes a thin-walled steel plate 4, a column 3, a cable 2 and an anchor seat 1. The anchor seat 1 is set on the upstream slope of the right bank of the dam at a position higher than the verified flood level. The columns 3 are evenly arranged along the arc-shaped dam axis with the anchor seat 1 as the center. The columns 3 are steel trusses, and their water-facing surface and both sides are continuous closed flat surfaces.

[0026] When the column 3 is set on the bedrock, the column 3 is fixed on the column foundation 31, and the column foundation 31 is fixed on the bedrock. The column foundation 31 is a reinforced concrete load-bearing anti-slip pile, which is connected to the column 3 by anchor bolts or embedded as a whole; When the column 3 is set on the sand and gravel sedimentary layer, the column 3 is erected on the raft 6, and a limit block 61 is set on the raft 6 to limit the rotation and displacement of the column 3. The sedimentary layer below the raft 6 is subjected to consolidation grouting treatment.

[0027] The top ends of all the columns 3 and the bottom ends of the columns 3 erected on the raft 6 , as well as the middle of the columns 3 and the anchor seat 1 are pulled with cables 2 to balance the horizontal thrust of the water carried by the columns 3 .

[0028] Between adjacent columns 3, the top ends are connected with support rods 5, and scissor braces are set up on the upstream facade; a cable rope 22 is connected to the top of the column 3 in the downstream direction of the dam line.

[0029] The thin-walled steel plates 4 are welded at both ends to the flat surfaces of adjacent columns 3. The thin-walled steel plates 4 are curled, with the center protruding downstream, forming a semicircular upright column surface with a diameter equal to the distance between the sides of the adjacent columns 3. The water-facing surfaces of the columns 3 and the thin-walled steel plates 4 are connected in sequence to form the dam surface. The columns 3 on both sides of the dam, or at the ends, are directly embedded in the rock wall or adjacent dam sections.

[0030] Pebbles 10 with a particle size of 2-4 cm are laid as a protective layer at the foot of the upstream side of the dam surface, and are thickened at the corners. A hydraulic fabric 72 is laid on the protective layer as a barrier layer, and fine-grained river sand 9 is laid on the barrier layer. A cushion layer of hydraulic fabric 72 is laid above the fine-grained river sand 9; above the cushion layer, a hydraulic membrane 7 is laid between the lower part of the dam surface and the anti-seepage wall 11 at the top of the anti-seepage curtain 12, and a water stop plate 71 is used at the edge of the hydraulic membrane 7 to seal the upstream dam surface and the anti-seepage wall 11 respectively; a cushion layer of hydraulic fabric 72 is laid between the hydraulic membrane 7 and the dam surface for protection.

[0031] The connection point of the cable 2 connected to the bottom end of the column 3 is lower than the position of the water-stop plate 71 on the column 3. The position where the cable 2 penetrates the hydraulic membrane is connected to the cable 2 and the hydraulic membrane 7 with a waterproof rod 8. The waterproof rod 8 is a solid metal rod with both ends connected to the cable 2. The waterproof rod 8 is provided with a water-stop ring 81 in the middle of the waterproof rod 8. A hole is opened in the hydraulic membrane 7, and the waterproof rod 8 is inserted into the hole. The outer edge of the hole in the hydraulic membrane 7 is fixed to the water-stop ring 81 via a flange 83 and an integral screw 82.

[0032] Follow these steps to build the thin-walled steel plate dam: S1, fix anchor seat 1 on the rock foundation above the verification flood level on the upstream slope of the right bank of the proposed dam location.

[0033] S2, the underground anti-seepage body base line 13 is arranged on the upstream side of the dam axis, connected with the anti-seepage bodies under the gravity dam on both sides and extended to both sides to form a continuous and closed underground anti-seepage base surface. The underground anti-seepage body of the dam foundation section includes an anti-seepage wall 11 and an anti-seepage curtain 12. The anti-seepage wall 11 is arranged on the top of the anti-seepage curtain 12, and a water stop plate 71 is buried on the top of the anti-seepage wall.

[0034] S3, excavate the dam foundation and divide it into sections according to depth. In the bedrock section, the cross section is trimmed into a vertical step-shaped bank slope. Concrete column foundations 31 are cast on the bedrock 16. The column foundations 31 are anti-slip piles with a bearing capacity that meets the requirements. The end of the column 3 is directly cast and connected to the foundation or the adjacent gravity dam 14 on the bank side. The riverbed sediment layer and the sand and gravel layer with good bearing capacity are retained. The upper layer is consolidated and grouting is strengthened to improve the bearing capacity and anti-scour capacity of the thin-walled steel plate dam section. A raft slab 6 is cast on the foundation grouting consolidation body 18 as an expanded foundation for the columns 3. The columns 3 are erected on the raft slab 6. On the raft slab 6 on both sides of the column foot, there are raised limit blocks 61 that can limit the rotation and displacement of the columns. The columns 3 are steel trusses, and their water-facing surface and both sides are continuous closed flat surfaces. The foundation between the raft slabs 6 is located below the thin-walled steel plates 4 and is poured with concrete to a height flush with the top surface of the raft slab 6 to control the gap between the thin-walled steel plates 4 and the foundation.

[0035] S4, set up brackets and scaffolding, cast and connect the columns 3 to the column foundation 31 or erect them on the raft 6; the height of the columns 3 in the D dam section is greater than 20m, and the columns 3 are vertically divided into two sections. In the middle of the column 3, 20m below the highest water level, a tensioning point is added to the anchor seat 1 to pull the cable 2. The support rods 5 and scissors braces between the columns 3 are divided into upper and lower layers with the corresponding tensioning points as the boundary.

[0036] S5. Between adjacent columns 3, at the top, struts 5 are used for butt joint connection, and the upstream elevation struts 5 are erected as X-braces; stay cables 22 are connected in the downstream direction of the dam line from the top of the columns 3. At both the top of all columns 3 and the bottom of the columns 3 fixed on the raft 6, tie cables 2 are tensioned between the columns and the anchor seats 1. The part of the tie cable 2 below the normal storage level is covered with floating bodies 21. Since the length of the tie cable 2 is greater than 4 times the diameter of the thin-walled steel plate 4, the tie cable 2 is arranged in sections. At the end close to the anchor seat 1, the adjacent tie cables are merged in pairs. At the position close to the columns 3, each tie cable is symmetrically divided into 3 strands and connected to 3 adjacent columns 3 respectively.

[0037] After all the tie cables 2 and stay cables 22 are connected, gradually tighten them symmetrically and cyclically. After the tie cables are tightened, the thin-walled steel plates 4 are welded and installed. The gap between the bottom surface of the thin-walled steel plates 4 and the raft 6 and the foundation is controlled within 1 cm. A water stop connection plate 71 is welded at the lower part of the water-facing surface of the thin-walled steel plates 4, and then the brackets and scaffolds are disassembled and removed.

[0038] S6. At the upstream toe of the dam, pebbles 10 with a particle size of 2 - 4 cm are laid as a protective layer, and the laying is thickened at the corners such as steps and the toe of the dam. A geotextile 72 interlayer is laid on the pebble layer, and a fine-grained river sand 9 cushion layer is laid on the interlayer. A geotextile 72 cushion layer is laid above the fine-grained river sand 9 cushion layer.

[0039] S7. The geomembrane 7 is covered. At the position where the tie cable 2 penetrates the geomembrane 7, a waterproof tie rod 8 is used for watertight connection between the tie cable 2 and the geomembrane 7. The waterproof tie rod 8 is a solid metal rod, and its two ends are respectively connected to the tie cable 2. A water stop ring 81 integrated with the waterproof tie rod 8 is arranged in the middle of the waterproof tie rod 8. An opening is made on the geomembrane 7, and the opening is fixed on the water stop ring 81 through a flange 83 and an integral screw rod 82; the top of the downstream side wall of the cut-off wall 11 under the geomembrane 7 is rounded and a protective layer is laid to protect the geomembrane.

[0040] Example 2: As Figure 1 shown, the length of the tie cable 2 is greater than 4 times the diameter of the coiled section of the thin-walled steel plate 4, and the tie cable 2 is arranged in sections. The tie cable 2 is merged near the anchor seat and bifurcated near the columns. Specifically: The columns 3 are divided into single-tie-cable columns and double-tie-cable columns, and the tie cable 2 is divided into a main tie cable and an auxiliary tie cable; A double-tie-cable column is arranged in the middle of the single-tie-cable columns; The main tie cable directly connected to the anchor seat is arranged on the single-tie-cable columns, and two auxiliary tie cables are arranged on the double-tie-cable columns. The included angles between the auxiliary tie cables and the connection line between the columns and the anchor seats are equal to ensure that the resultant force direction of the double tie cables points to the anchor seat; The auxiliary tie cables are respectively connected to the main tie cables on both sides; at the bifurcation points of the main tie cables, auxiliary tie cables with equal included angles with the main tie cables are branched out to both sides to balance the lateral tension, or other measures are taken to ensure that the position of the main tie cable does not shift.

[0041] The columns 3 at both ends of the described thin-walled steel plate dam are embedded in the adjacent concrete gravity dam 14. Auxiliary cables are connected to the columns 3 at the ends to play a balancing role to ensure that the positions of the adjacent main cables do not shift.

[0042] Other structures and construction methods of the thin-walled steel plate dam are the same as those in Embodiment 1.

Claims

1. A thin-walled steel plate dam, characterized in that It includes thin-walled steel plates, columns, cables, anchor seats and hydraulic membranes. The anchor seats are set on the upstream slope of the dam at a position higher than the verified flood level. Columns are evenly arranged along the arc-shaped dam axis with the anchor seats as the center. The columns are steel trusses with continuous closed flat surfaces on both sides of the water-facing surface. The columns and anchor seats are connected by cables. Adjacent columns are connected top to top with support rods, and scissor braces are installed on the upstream facade; guy ropes are connected at the top of the columns toward the downstream of the dam line; The two ends of the thin-walled steel plate are welded to the flat surface of the adjacent columns. The thin-walled steel plate is curled, and the middle curled section protrudes downstream to form an upright semicircular cylinder with a diameter equal to the distance between the side surfaces of the adjacent columns. The water-facing surface of the columns and the thin-walled steel plate are connected in sequence to form the water retaining dam surface. The edges or end columns on both sides of the retaining dam are directly embedded in the rock wall or adjacent dam section; a hydraulic membrane is laid between the lower part of the retaining dam surface and the anti-seepage wall at the top of the anti-seepage curtain, and water stop plates are used at the edges of the hydraulic membrane to seal the water-facing surface of the column and the anti-seepage wall respectively; a protective layer is set under the hydraulic membrane, hydraulic cloth is laid on steep areas, and fine-grained river sand is laid on flat areas.

2. The thin-walled steel plate dam according to claim 1, characterized in that When the column is set at the bedrock, the column is fixed on the column foundation, and the column foundation is fixed on the bedrock. The column foundation is a reinforced concrete load-bearing anti-slip pile, which is connected to the column anchor bolt or buried as a whole.

3. A thin-walled steel plate dam as claimed in claim 1, wherein When the column is set at a sedimentary layer with stable bearing capacity, the column is fixed on the raft, and a limit block is set on the raft to limit the rotation and displacement of the column. The sedimentary layer below the raft is subjected to consolidation grouting treatment.

4. A thin-walled steel plate dam according to claim 2, characterized in that The top ends of all the columns and the bottom ends of the columns fixed on the raft slab are connected to the anchor seats with cables, and the connection points of the cables connected to the bottom ends of the columns are lower than the positions of the water stop plates on the columns.

5. A thin-walled steel plate dam as claimed in claim 1, characterized in that When the cable length is greater than 4 times the diameter of the thin-walled steel plate curled section, a segmented arrangement is adopted. The cables merge near the anchor seat and branch near the column. Specifically: The columns are divided into single-cable columns and double-cable columns, and the cables are divided into main cables and auxiliary cables; At least one double-stayed cable column is arranged equidistantly between the single-stayed cable columns; A main cable connected in a straight line to the anchor seat is set on the single-stay column, and two auxiliary cables are set on the double-stay column. The angle between the auxiliary cables and the line connecting the column and the anchor seat is equal to ensure that the direction of the resultant force of the double cables points to the anchor seat; The auxiliary cables are connected to the main cables on both sides respectively. At each bifurcation point of the main cables, auxiliary cables with the same angle as the main cables are branched out to both sides to balance the tension on both sides, or other measures are taken to ensure that the position of the main cables does not shift.

6. A thin-walled steel plate dam as claimed in claim 1, wherein The portion of the cable located below the normal water level covers the floating body.

7. A thin-walled steel plate dam according to claim 1, characterized in that When the water depth at the location of the thin-walled steel plate dam is greater than 20m, the columns are vertical layered trusses, each layer is provided with braces and scissors braces, and cables are pulled between the middle of the columns and the anchor seats.

8. A thin-walled steel plate dam according to claim 1, characterized in that A waterproof pull rod is used to watertightly connect the cable and the hydraulic membrane at the position where the cable penetrates the hydraulic membrane. The waterproof pull rod is a solid metal rod, and its two ends are respectively connected to the cable. A water stop ring integrated with the waterproof pull rod is provided in the middle of the waterproof pull rod. A hole is opened on the hydraulic membrane, and the waterproof pull rod is inserted into the hole. The outer edge of the hole in the hydraulic membrane is fixed to the water stop ring through a flange and an integrated screw.

9. A construction method of a thin-walled steel plate dam, characterized in that The following steps are involved: S1. Fix the anchor seat on the rock foundation above the checking flood level on the upstream slope of the dam. S2. Arrange the underground anti-seepage system of the dam upstream of the axis of the thin-walled steel plate dam. Set a reinforced concrete anti-seepage wall at the top of the anti-seepage system, and embed an anti-seepage water-stop connecting plate at the top of the wall. S3. Excavate the dam foundation. Segment by depth and trim the cross-section into a stepped shape with a vertical bank slope. In the area where the foundation is bedrock, pour a concrete column foundation on the foundation. The column on the shore side at the end is directly poured and connected to the column foundation as a whole. In the area where the foundation is a stable sediment layer, carry out consolidation grouting and other strengthening treatments to improve the bearing capacity and anti-scouring ability of the base surface. Pour a raft on the foundation as an enlarged foundation for the column. The column is erected on the raft, and limit blocks for restricting the rotation and displacement of the column are set on both sides of the column foot. The foundation between the rafts is poured with concrete to the same height as the top surface of the raft at the position below the thin-walled steel plate. S4. Set up supports and scaffolds, and pour and connect the columns to the column foundation or erect them on the rafts. S5. Install struts and diagonal braces, stretch cables and guy ropes. Cover the cables below the normal storage level with floating bodies. After all the cables and guy ropes are connected, gradually tighten them symmetrically in a cycle. After the cables are tightened, weld the thin-walled steel plate to the column. The gap between the bottom surface of the thin-walled steel plate and the raft and the foundation is less than 1 cm. Weld a water-stop connecting plate at the lower part of the water-retaining dam surface. After completion, remove the supports and scaffolds. S6. Lay pebbles with a particle size of 2 - 4 cm at the upstream toe of the water-retaining dam surface as a protective layer, and thicken the laying at the corners. Lay a geotextile as an interlayer on the protective layer, lay fine-grained river sand on the geotextile, and lay a geotextile above the fine-grained river sand. S7. Cover the geomembrane, and make a waterproof connection between the geomembrane and the water-stop connecting plate and the waterproof tie rod. For the structures under the membrane, round off the protruding parts in contact with the geomembrane or lay a protective layer.

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