Supporting method and supporting structure for cave-type excavation gravity dam

Abstract

The application discloses a supporting method and structure for cave-type excavation of a gravity dam, which comprises the following steps: S1, installing an arch frame (1) in a construction hole (28) and a grouting hole (29) when the construction hole (28), the grouting hole (29) and a slope cleaning surface (30) are excavated, and arranging a tensile bar (2) and a steel mesh (3) between adjacent arch frames (1); S2, further fixing the arch frame (1) through an anchor rod (6); S3, spraying concrete on the surface of the steel mesh (3) to form a first concrete layer (4), and layering the concrete in the steel mesh (3) to form a second concrete layer (5); S4, cleaning the slope cleaning surface (30) and leveling the slope cleaning surface (30); and S5, arranging a steel support on the slope cleaning surface (30). The application can reliably support the excavated mountain body and has high stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a supporting method and a supporting structure, in particular to a supporting method and a supporting structure for a cave-type excavation of a gravity dam. BACKGROUND

[0002] The dam shoulder of a gravity dam refers to the slope part on both sides of the upstream and downstream of the gravity dam, which plays a role in supporting and stabilizing the gravity dam. The design purpose of the gravity dam is to resist the water pressure behind the dam by its own weight, so the stability of the dam shoulder is very important for the safety of the entire gravity dam. The conventional dam shoulder excavation of an arch dam adopts open excavation, and for the terrain with steep slopes on both banks, the following defects exist: the height and range of slope excavation are large, the safety risk of the slope is high, and the excavation and supporting engineering quantity is large.

[0003] In order to reduce the impact on the slope, a high and steep terrain gravity dam shoulder excavation structure is disclosed in the patent with application number 202320354667.6, which includes a dam shoulder construction hole, the dam shoulder construction hole is a cave-type structure, a grouting traffic hole is arranged on one side of the dam shoulder construction hole, both sides of the bottom of the dam shoulder construction hole are arranged as inwardly curved arc structures, and a boss structure is arranged on the inner side of the bottom of the dam shoulder construction hole. The dam shoulder construction hole is a cave-type structure, which ingeniously combines the requirements of gravity dam foundation treatment and dam shoulder slope stability with the size of the dam body and the topographic and geological conditions, and reduces the damage of engineering construction to the environment. When constructing, the mountain needs to be excavated, which is easy to cause soil layer to fall off and cause safety hazards. SUMMARY

[0004] The purpose of the present application is to provide a supporting method and a supporting structure for a cave-type excavation of a gravity dam. It can reliably support the excavated mountain and has high stability.

[0005] The technical solution of the present application: a supporting method and a supporting structure for a cave-type excavation of a gravity dam, comprising the following steps:

[0006] S1, when excavating the construction hole, the grouting flat hole and the slope cleaning surface, installing arches in the construction hole and the grouting flat hole, and arranging reinforcing bars and steel mesh between adjacent arches;

[0007] S2, further fixing the arches by anchor rods;

[0008] S3, spraying concrete on the surface of the steel mesh to form a first concrete layer, and layering the concrete in the steel mesh to form a second concrete layer;

[0009] S4, cleaning the slope cleaning surface and leveling the slope cleaning surface;

[0010] S5, arranging steel supports on the slope cleaning surface.

[0011] The construction hole bottom surface height is at the same height as the dam top surface.

[0012] The support structure corresponding to the cave-type excavation gravity dam support method comprises a steel support arranged on the slope cleaning surface and a shotcrete support structure with a mesh arranged on the construction hole and the grouting tunnel.

[0013] The shotcrete support structure with a mesh comprises spliced arches uniformly distributed along the depth direction of the construction hole and the grouting tunnel, horizontal setting reinforcing bars arranged between adjacent arches, a steel mesh arranged in the reinforcing bars, a first concrete layer arranged on the surface of the steel mesh, a second concrete layer arranged on the inner side of the steel mesh, and anchor rods arranged vertically and radially in the first and second concrete layers.

[0014] The arches comprise feet arranged at both ends, and the feet are provided with arch segments movable relative to the feet.

[0015] The feet comprise a bottom plate arranged at the bottom, a sleeve rotatable relative to the bottom plate arranged on the bottom plate, a rotating shaft arranged on the inner side of the bottom of the sleeve, a limiting shaft arranged in the middle of the sleeve, a limiting nut arranged at the end of the limiting shaft, a fixed seat corresponding to the rotating shaft arranged on the bottom plate, limiting plates arranged on both sides of the sleeve, limiting grooves corresponding to the limiting shaft arranged in the limiting plates, and a wedge block mechanism arranged on one side of the limiting plates for adjusting the angle between the bottom plate and the sleeve.

[0016] The wedge block mechanism comprises a bidirectional screw rod arranged in the bottom plate, a moving block arranged on the bidirectional screw rod, a wedge block arranged on the moving block, and a limiting groove corresponding to the moving block arranged on the bottom plate.

[0017] One end of the arch segment is provided with a tenon block, the other end of the arch segment is provided with a mortise corresponding to the tenon block, the tenon block and the mortise are provided with positioning holes, and a reinforcing rib is arranged outside the arch segment.

[0018] The sleeve is provided with a connecting groove corresponding to the arch segment, the connecting groove is provided with a guide groove corresponding to the reinforcing rib on one side, and the connecting groove is provided with a locking screw rod on one side.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] 1、The application is directed to a cave type excavation gravity dam, a steel support and a net anchor shotcrete support structure are used to form support for the gravity dam abutment, and reliable support for the excavated mountain body, through the cooperation of the arch frame, the reinforcing bar and the steel mesh, the preliminary support for the arch top soft soil layer is realized, the anchor rod can improve the support effect, form the overall support effect, the support strength is high, the steel support can prevent mountain rockfall, and the safety is good;

[0021] 2、The arch joint of the application can move relative to the foot, thereby reducing the overall size of the arch frame, facilitating the delivery into the construction hole and the grouting flat hole, and the construction is more convenient;

[0022] 3、The arch joint of the application is connected through the cooperation of the tenon block and the mortise under the action of external pressure, and can be further pressed tightly, the stability is good, the bottom plate at the lower part of the foot can rotate relative to the sleeve, so that the two bottom plates are always on the same plane, facilitating transportation and not easy to fall. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic view of the application;

[0024] Figure 2 is a structural schematic view of the application;

[0025] Figure 3 is a structural schematic view of the arch frame of the application;

[0026] Figure 4 is a structural schematic view of the arch joint of the application;

[0027] Figure 5 is a structural schematic view of the sleeve of the application;

[0028] Figure 6 is a structural schematic view of the wedge block mechanism of the application.

[0029] The marks in the drawings are: 1-arch frame, 2-reinforcing bar, 3-steel mesh, 4-first concrete layer, 5-second concrete layer, 6-anchor rod, 7-foot, 8-arch joint, 9-bottom plate, 10-sleeve, 11-rotation shaft, 12-limiting plate, 13-limiting shaft, 14-limiting slot, 15-limiting nut, 16-bidirectional screw rod, 17-moving block, 18-wedge block, 19-limiting slot, 20-tenon block, 21-mortise, 22-positioning hole, 23-stiffening rib, 24-connecting slot, 25-guiding slot, 26-locking screw rod, 27-fixing seat, 28-construction hole, 29-grouting flat hole, 30-slope cleaning surface. DETAILED DESCRIPTION

[0030] The technical solutions of the application will be further specifically described below through embodiments and in combination with the drawings.

[0031] Embodiment 1. A supporting method for cave-type excavation of a gravity dam, comprising the following steps as shown in the accompanying drawings: Figures 1-6

[0032] S1, when excavating the construction hole 28, the grouting hole 29 and the slope cleaning surface 30, installing the arch frame 1 in the construction hole 28 and the grouting hole 29, and arranging the reinforcing bar 2 and the steel mesh 3 between adjacent arch frames 1, Figure 1 The dashed line represents the original slope line. The original slope is excavated to form the construction hole 28, the grouting hole 29 and the slope cleaning surface 30, and the supporting is carried out during the excavation to form a stable support and avoid safety accidents.

[0033] S2, further fixing the arch frame 1 by the anchor rod 6;

[0034] S3, spraying concrete on the surface of the steel mesh 3 to form the first concrete layer 4, and layering the concrete in the steel mesh 3 to form the second concrete layer 5;

[0035] S4, cleaning the slope cleaning surface 30 and leveling the slope cleaning surface 30;

[0036] S5, arranging the steel support on the slope cleaning surface 30.

[0037] The bottom surface height of the construction hole 28 is at the same height as the top surface of the dam.

[0038] The supporting method for cave-type excavation of a gravity dam corresponds to a supporting structure, which comprises the steel support arranged on the slope cleaning surface 30 and the net-hanging anchor-shotcrete supporting structure arranged on the construction hole 28 and the grouting hole 29.

[0039] The net-hanging anchor-shotcrete supporting structure comprises the spliced arch frame 1 uniformly distributed along the depth direction of the construction hole and the grouting hole, the reinforcing bar 2 arranged horizontally between adjacent arch frames 1, the steel mesh 3 arranged in the reinforcing bar 2, the first concrete layer 4 arranged on the surface of the steel mesh 3, the second concrete layer 5 arranged on the inner side of the steel mesh 3, and the anchor rod 6 arranged vertically and radially in the first concrete layer 4 and the second concrete layer 5.

[0040] The arch frame 1 comprises the foot 7 at both ends, and the arch joint 8 movably arranged in the foot 7.

[0041] The foot 7 comprises the bottom plate 9 at the bottom, the sleeve 10 rotatably arranged on the bottom plate 9, the pivot shaft 11 arranged on the inner side of the bottom of the sleeve 10, the limiting shaft 13 arranged in the middle of the sleeve 10, the limiting nut 15 arranged at the end of the limiting shaft 13, the fixed seat 27 corresponding to the pivot shaft 11 arranged on the bottom plate 9, the limiting plate 12 arranged on the bottom plate 9 and located on both sides of the sleeve 10, the limiting groove 14 corresponding to the limiting shaft 13 arranged in the limiting plate 12, and the wedge block mechanism for adjusting the angle between the bottom plate 9 and the sleeve 10 arranged on one side of the limiting plate 12.​

[0042] The wedge block mechanism comprises a bidirectional screw rod 16 arranged in the bottom plate 9, a moving block 17 arranged on the bidirectional screw rod 16, a wedge block 18 arranged on the moving block 17, and a limiting groove 19 corresponding to the moving block 17 arranged on the bottom plate 9.

[0043] The arch joint 8 is provided with a tenon block 20 at one end, a tenon groove 21 corresponding to the tenon block 20 at the other end, and a positioning hole 22 arranged on the tenon block 20 and the tenon groove 21, and a reinforcing rib 23 arranged outside the arch joint 8.

[0044] The sleeve 10 is provided with a connecting groove 24 corresponding to the arch joint 8, a guide groove 25 corresponding to the reinforcing rib 23 arranged on one side of the connecting groove 24, and a locking screw 26 arranged on one side of the connecting groove 24.

[0045] The application is a supporting method and structure for cave-type excavation of gravity dam, which supports the gravity dam during the excavation of the dam abutment. Figure 1 As shown in the figure, the gravity dam abutment structure comprises a construction hole, a grouting hole and a slope cleaning surface, the slope is supported by steel support as claimed in application No. 202320354667.6, and the construction hole and the grouting hole are supported by a hanging net anchor shotcrete support structure. When the hanging net anchor shotcrete support structure is installed, the installation of the arch frame 1 is carried out first. During the transportation of the arch frame, the arch joint 8 is moved relative to the support foot 7 to adjust the overall size of the arch frame 1, so that the arch frame can be more conveniently and easily transported into the construction hole and the grouting hole, and the transportation vehicle can also more conveniently transport the arch frame. However, when the relative position of the arch joint and the support foot is adjusted, the angle of the bottom plate 9 under the support foot 7 will change, the contact area of the support foot 7 with the ground is small when the support foot 7 is placed, it is difficult to place stably, and the bottom plate 9 is unevenly stressed, which is easy to cause damage.

[0046] The application can drive the moving block 17 to move through the bidirectional screw rod 16. The bidirectional screw rod 16 can be driven to move through the rocker or motor arranged at the end of the bidirectional screw rod 16. The relative position of the wedge block 18 and the sleeve 10 can be adjusted during the movement of the moving block 17. After the adjustment, the relative position of the bottom plate 9 and the sleeve 10 is locked through the tightening of the limiting nut 15, so that the angle of the bottom plate 9 can be changed, and the bottom plate 9 can be stably attached to the ground or the bottom surface of the carrying vehicle, thereby facilitating the conveying work and reducing the possibility of damage. The application adjusts the relative angle of the bottom plate and the sleeve through the bidirectional screw rod, which is more accurate, and the wedge block can support the sleeve, thereby reducing the force borne by the limiting shaft 13 and the limiting nut. The bidirectional screw rod can enable the wedge block to move symmetrically with the center of the sleeve 10 and the bottom plate 9, and the two wedge blocks can support the sleeve 10 in the same way, thereby balancing the force. The arch segments 8 are connected through the cooperation of the tenon blocks 20 and the mortise grooves 21, and the arch segments are convenient to disassemble and assemble. Since the construction hole 28 and the grouting flat hole 29 have small spaces, the arch segments are generally conveyed into the construction hole 28 and the grouting flat hole 29 after being assembled outside. The relative movement of the supporting legs and the arch segments can adjust the overall size of the arch segments, thereby facilitating the conveying. During the construction, the downward force borne by the arch frame 1 can make the connection between the arch segments 8 more compact, the reinforcing ribs on the surface of the arch segments can improve the bearing capacity of the arch segments, and the reinforcing ribs 23 can further limit and guide the relative position adjustment between the sleeve 10 and the arch segments 8, thereby improving the connection stability.

[0047] The arch frame is matched with the construction hole 28 and the grouting flat hole 29. The arch frame is sent into the construction hole 28 and the grouting flat hole 29 in a shortened state, and then the positions between the arch segments 8 and between the arch segments and the supporting legs are adjusted, so that the arch frame is attached to the construction hole 28 and the grouting flat hole 29. Then, the tie bars 2 and the steel mesh 3 are installed, and further fixed through the anchor rods. The application sprays concrete through the spraying device to form the first concrete layer 4 on the surface of the steel mesh. After the first concrete layer 4 is coagulated, multiple grouting is performed from bottom to top through the grouting holes reserved in the first concrete layer, thereby forming the second concrete layer 5, and the supporting effect is better. The surface of the slope cleaning surface 30 is fixed through the steel support after being cleaned and leveled, thereby reducing the risk of rock falling and improving the safety.

Claims

1. A method of supporting a gravity dam of the cave type, characterized in that, The supporting structure comprises steel supports arranged on the slope cleaning surface (30) and a hanging net anchor shotcrete supporting structure arranged on the construction hole (28) and the grouting flat hole (29); the hanging net anchor shotcrete supporting structure comprises spliced arch frames (1) uniformly distributed along the depth direction of the construction hole (28) and the grouting flat hole (29), horizontal setting of the pull bars (2) is arranged between adjacent arch frames (1), the pull bars (2) are internally provided with the steel mesh (3), the surface of the steel mesh (3) is provided with the first concrete layer (4), the inner side of the steel mesh (3) is provided with the second concrete layer (5), and the first concrete layer (4) and the second concrete layer (5) are provided with the anchor rods (6) arranged in the vertical radial direction; the arch frame (1) comprises the feet (7) at two ends, the feet (7) are internally provided with the arch joints (8) capable of moving relative to the feet (7); the foot (7) comprises the bottom plate (9) at the bottom, the sleeve (10) capable of rotating relative to the bottom plate (9) is arranged on the bottom plate (9), the bottom inner side of the sleeve (10) is provided with the rotating shaft (11), the middle part of the sleeve (10) is provided with the limiting shaft (13), the end part of the limiting shaft (13) is provided with the limiting nut (15), the bottom plate (9) is provided with the fixed seat (27) corresponding to the rotating shaft (11), the bottom plate (9) is provided with the limiting plates (12) separately arranged on the two sides of the sleeve (10), the limiting plate (12) is internally provided with the limiting groove one (14) corresponding to the limiting shaft (13), and the limiting plate (12) is provided with the wedge block mechanism for the angle relative adjustment of the bottom plate (9) and the sleeve (10) on one side. Specifically comprising the following steps: S1, when the construction hole (28), the grouting flat hole (29) and the slope cleaning surface (30) are excavated, the arch frames (1) are installed in the construction hole (28) and the grouting flat hole (29), and the pull bars (2) and the steel mesh (3) are arranged between adjacent arch frames (1); S2, the arch frames (1) are further fixed through the anchor rods (6); S3, the first concrete layer (4) is formed by spraying concrete on the surface of the steel mesh (3), and the second concrete layer (5) is formed by layering pouring concrete in the steel mesh (3); S4, the slope cleaning surface (30) is cleaned and leveled; S5, the steel supports are arranged on the slope cleaning surface (30).

2. The method of supporting a cavern excavated gravity dam as claimed in claim 1 wherein: The bottom surface height of the construction hole (28) is at the same height as the top surface of the dam.

3. The method of supporting a cavern excavated gravity dam as claimed in claim 1 wherein: The wedge block mechanism comprises the bidirectional screw rod (16) arranged in the bottom plate (9), the moving block (17) is arranged on the bidirectional screw rod (16), the wedge block (18) is arranged on the moving block (17), and the limiting groove two (19) corresponding to the moving block (17) is arranged on the bottom plate (9).

4. The method of supporting a cavern excavated gravity dam as claimed in claim 1 wherein: One end of the arch joint (8) is provided with the tenon block (20), the other end of the arch joint (8) is provided with the mortise groove (21) corresponding to the tenon block (20), the tenon block (20) and the mortise groove (21) are provided with the positioning hole (22), and the arch joint (8) is externally provided with the reinforcing rib (23).

5. The method of supporting a cavern excavated gravity dam as claimed in claim 1 wherein: The sleeve (10) is provided with a connecting groove (24) corresponding to the arch joint (8), one side of the connecting groove (24) is provided with a guide groove (25) corresponding to the reinforcing rib (23), and one side of the connecting groove (24) is provided with a locking screw rod (26).

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