Deep foundation pit supporting structure for backfill slag area of strip mine pit
By using threaded steel bars and steel mesh and other materials in the backfill slag area of open-pit pits to build a plum-shaped deep foundation pit support structure, the problems of large deformation and inconsistency in the soil nail support technology are solved, and the slope stability and construction aesthetics are improved.
Patent Information
- Application Number
- CN202420739853.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-11
- Publication Date
- 2025-04-18
- Estimated Expiration
- 2034-04-11
AI Technical Summary
The existing soil nail support technology has problems of large deformation and inconsistent stress in the backfill slag area of open-pit pits, resulting in poor slope stability and prone to landslides and landslides and landslide accidents.
Threaded steel bars are used instead of anchor rods to arrange them in plum blossoms, and steel mesh and reinforcement bars are installed on the slope. By spraying concrete, an integral support structure is formed to improve slope stability.
While saving costs, it improves slope stability, reduces the risk of landslides, and avoids the problem of incoordination of stress between anchor rods and soil nails.
Smart Images
Figure CN222771502U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of deep foundation pit support, and in particular relates to a deep foundation pit support structure used for backfilling slag areas in open pits. Background Art
[0002] In the reinforcement and support technology of mines and underground projects, soil nail support technology is widely used. However, due to the serious problem of large deformation of soil nail support pits, its engineering application is subject to certain restrictions. In order to solve the engineering problem of large deformation of soil nail support pits, the actual engineering often adopts the construction measures of combining prestressed anchor rods with soil nails, and controls the deformation of the pit by applying prestress to the anchor rods. However, soil nails belong to passive support technology, that is, only when the pit is deformed, the soil nails begin to passively bear the force and play a role, while the purpose of prestressed anchor rods is to reduce or even eliminate the deformation of the pit, which leads to the uncoordinated force between soil nails and prestressed anchor rods, and the bearing capacity of the two cannot be fully exerted at the same time.
[0003] At present, the on-site earthwork in the open-pit mine industrial area is the original open-pit coal mining rock stripping waste soil, which contains a large amount of stone. Since the earthwork that needs to be excavated at the construction site is artificial backfill slag, the soil layer contains a large amount of lumps, etc., it is difficult to construct soil nails in the backfill soil, and the construction period is delayed. In addition, the construction period is in the rainy season, and because of the low terrain and the blockage of drainage on the upper slope, most of the water from the original upstream national highway and rainwater seep into the ground. The foundation pit slope has already landslided and there is a risk of continued landslide. If the seepage is not treated before the slope excavation and support is not carried out in time, landslide accidents are likely to occur.
[0004] Therefore, it is urgent to design a deep foundation pit support structure to avoid the problem of uncoordinated force between anchor rods and soil nails and improve the slope protection capability. Utility Model Content
[0005] The purpose of the utility model is to overcome the deficiencies in the prior art and provide a deep foundation pit support structure for backfilling slag areas in open-pit mines, wherein threaded steel bars are used instead of anchor rods in a plum blossom arrangement, and steel meshes and reinforcing bars are arranged on the slopes. The steel meshes are fixed to the slopes with friction anchor U-shaped steel bars, thereby saving costs and integrating the steel bars replacing the anchor rods, the steel meshes and the slopes, thereby improving the stability of the slopes.
[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a deep foundation pit support structure for backfilling slag areas in open-pit mines, the deep foundation pit support structure is formed by integrally forming threaded steel bar soil nails, first reinforcement bars, steel mesh, second reinforcement bars and drain pipes arranged perpendicular to the slope in the foundation pit body through shotcrete; the threaded steel bar soil nails are arranged in a plum blossom shape on the slope, the first reinforcement bars include first transverse reinforcement bars and first longitudinal reinforcement bars, the first transverse reinforcement bars and the first longitudinal reinforcement bars are fixedly connected to the threaded steel bar soil nails by welding to form an integral structure; the steel mesh is supported and connected above the threaded steel bar soil nails by the second reinforcement bars, and is fixedly connected to the slope by friction anchor U-shaped steel bar clips, the second reinforcement bars include second transverse reinforcement bars and second longitudinal reinforcement bars, and concrete is arranged above the steel mesh; the drain pipe is arranged in a plum blossom shape on the slope, the outside of the drain pipe protrudes from the concrete, a plurality of drainage holes are evenly distributed in the soil section inside the drain pipe, and a fine stone filter bag wrapped with filter cloth is arranged outside the drainage hole.
[0007] The threaded steel bar soil nails and the first reinforcement bar are both made of C16 threaded steel bars.
[0008] The transverse spacing and row spacing of the threaded steel bar soil nails on the slope are both 1500mm.
[0009] The size of the steel mesh is A6.5@250*250, and the second reinforcement bar is C14 threaded steel bar.
[0010] The overlap width of the steel mesh is not less than 10 cm, and the overlap is fixed with C16 U-shaped steel bar clips.
[0011] The drainage pipe adopts A75UPVC pipe. The horizontal spacing and row spacing of the drainage pipe on the slope of the foundation pit are both 3000mm, the depth of burial is 500mm, and the fine stone filter capsule contains 20mm diameter crushed stone and 1-4mm gravel or stone chips.
[0012] A construction ramp is arranged on one side of the foundation pit body from the upper edge line of the foundation pit to the bottom edge line of the foundation pit, and a slope is arranged in the remaining area between the upper edge line of the foundation pit and the bottom edge line of the foundation pit. The slope includes an upper slope and a lower slope, and a middle platform of the foundation pit is arranged between the upper slope and the lower slope.
[0013] The slope coefficients of the upper slope and the lower slope are both 1:1, and the slope coefficient of the construction ramp is 1:6.
[0014] Drainage ditches are arranged on the top of the upper slope, the middle of the platform in the middle of the foundation pit and the bottom of the lower slope.
[0015] The beneficial effects of the utility model are:
[0016] 1) In the structure of the utility model, threaded steel bars are used to replace anchor rods in a plum blossom arrangement. At the same time, steel mesh and reinforcing bars are set on the slope. The steel mesh is fixed to the slope with friction anchor U-shaped steel bars. While saving costs, the steel bars replacing the anchor rods, the steel mesh and the slope are connected as one, which will not occupy the construction area, making the foundation pit more beautiful, improving the stability of the slope and reducing the risk of landslides.
[0017] 2) In the utility model, C16 threaded steel bars are used to replace anchor rods in a plum blossom arrangement. At the same time, C14 transverse and longitudinal reinforcing ribs are arranged at the ends of the anchor rods and fixed to the ends of the C16 threaded steel bars by welding, so that the threaded steel bars and the reinforcing ribs become an integrated structure, avoiding the uncoordinated force between the anchor rods and the soil nails, and improving the anchoring stability. This connection method not only saves money, but also facilitates material preparation and construction. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the plan structure of foundation pit excavation of the utility model;
[0019] Figure 2 It is a schematic diagram of the elevation structure of the foundation pit excavation of the utility model;
[0020] Figure 3 for Figure 1 Partial cross-section of the middle support structure;
[0021] Figure 4 for Figure 1 Sectional view of the middle support structure;
[0022] Figure 5 for Figure 3 Cross-section of the drain pipe.
[0023] In the figure, 1-threaded steel soil nails, 2-first reinforcement, 201-first transverse reinforcement, 202-first longitudinal reinforcement, 3-steel mesh, 4-second reinforcement, 401-second transverse reinforcement, 402-second longitudinal reinforcement, 5-drain pipe, 501-drainage hole, 502-fine stone filter bag, 6-concrete, 7-upper edge line of foundation pit, 8-bottom edge line of foundation pit, 9-upper slope, 10-lower slope, 11-middle platform of foundation pit, 12-construction ramp, 13-drainage ditch. DETAILED DESCRIPTION
[0024] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.
[0025] Example: Figure 1~Figure 4As shown, the utility model provides a deep foundation pit support structure for backfilling slag areas in open-pit mines. The deep foundation pit support structure is formed in one piece by shotcrete 6 through threaded steel soil nails 1 embedded in the slope of the foundation pit body, first reinforcement ribs 2, steel mesh 3, second reinforcement ribs 4 and drain pipes 5.
[0026] The threaded steel bar soil nail 1 is made of C16 threaded steel bars arranged in a plum blossom shape on the slope, and the transverse spacing and row spacing are both 1500 mm; the first reinforcement rib 2 also uses C16 threaded steel bars, and the first reinforcement rib 2 includes a first transverse reinforcement rib 201 and a first longitudinal reinforcement rib 202. The first transverse reinforcement rib 201 and the first longitudinal reinforcement rib 202 are fixedly connected to the threaded steel bar soil nail 1 by welding to form an integral structure. The material is easy to obtain and the friction force is increased.
[0027] The size of the steel mesh 3 is A6.5@250*250, and the second reinforcement rib 4 is C14 threaded steel bar. The steel mesh 3 is supported and connected above the threaded steel bar soil nail 1 through the second reinforcement rib 4, and is fixed to the slope through the friction anchor U-shaped steel bar clamp. The overlap width of the steel mesh 3 is not less than 10 cm, and the overlap is fixed with a C16 U-shaped steel bar clamp; the second reinforcement rib 4 includes a second transverse reinforcement rib 401 and a second longitudinal reinforcement rib 402, and the concrete 6 is arranged above the steel mesh 3.
[0028] The drain pipe 5 adopts A75UPVC pipe and is arranged in a plum blossom shape on the slope, with a lateral spacing and row spacing of 3000mm and a burial depth of 500mm. The outside of the drain pipe 5 extends out of the concrete 6, and a plurality of drainage holes 501 are evenly distributed in the internal buried section, and a fine stone filter capsule 502 wrapped with filter cloth is arranged outside the drainage hole 501 to wrap it. The fine stone filter capsule 502 is wrapped with filter cloth, and the fine stone filter capsule contains crushed stone with a diameter of 20mm and gravel or stone chips with a diameter of 1 to 4mm.
[0029] A construction ramp 12 is provided on one side of the foundation pit body from the upper edge line 7 of the foundation pit to the bottom edge line 8 of the foundation pit, and the remaining area is set as a slope between the upper edge line 7 of the foundation pit and the bottom edge line 8 of the foundation pit. The slope includes an upper slope 9 and a lower slope 10. A middle platform 11 of the foundation pit is provided between the upper slope 9 and the lower slope 10. Drainage ditches 13 are provided on the top of the upper slope 9, the middle of the middle platform 11 of the foundation pit and the bottom of the lower slope 10.
[0030] The slope coefficients of the upper slope 9 and the lower slope 10 are both 1:1, and the slope coefficient of the construction ramp 12 is 1:6.
[0031] The construction steps of the above-mentioned deep foundation pit support structure are as follows:
[0032] To prevent rainwater from entering the foundation pit, a 300×300mm intercepting ditch is set at the top of the foundation pit, and the slope inside the ditch is greater than 0.5%; the ditch bottom uses a 60mm thick C15 plain concrete cushion layer, the side walls are made of 120mm thick bricks, and the inside is applied with 20mm thick 1:2 cement mortar.
[0033] like Figure 1 As shown, according to the investigation report, this area is determined to be a backfill area. The excavation depth of the foundation pit is about 11.3m. The foundation pit is excavated in two layers, and the excavation depth of each layer is about 5.6-5.7m. A 3m wide platform is set in the middle of the foundation pit. When excavating the foundation pit, the slope coefficients on the west, south and north sides are 1:1, and a 1:6 construction ramp is set on the east side of the foundation pit.
[0034] like Figure 2 As shown, the main body of the friction anchor is replaced by C16 threaded steel bar soil nails. The length of the steel bar anchored in the soil is not less than 3.0m for the upper layer and not less than 1.5m for the lower layer. Before insertion, the anchor rod body is placed by the driving method. The construction machinery is QC-150 anchor machine. During construction, the anchor position is required to be within ±5cm of the design position. After the soil nails are driven into the soil, they are constructed perpendicular to the slope. The average horizontal spacing is 1.5m, and the row spacing is 1.5m, arranged in a plum blossom shape.
[0035] After the slope is excavated, the slope gradient ratio is based on the 1:1 construction requirement, and the loose soil and excess soil on the slope are manually trimmed off. No loose soil or stones are reserved on the slope before the mesh construction.
[0036] After the slope repair is completed, proceed with the mesh hanging operation. Fix the steel mesh on the slope with friction anchor U-shaped steel bar clips. The overlap width of the steel mesh should be no less than 10cm, and the overlap needs to be fixed with C16 U-shaped steel bar clips.
[0037] After hanging the net, bury the drainage pipe, drill holes in the upper half of the drainage pipe, and wrap it with fine stone filter bags wrapped with filter cloth (501) at a spacing of 3000mm in a plum blossom shape. The fine stone filter bags contain 20mm diameter gravel and 1-4mm gravel or stone chips. Finally, spray 100mm C20 concrete on the slope for reinforcement.
[0038] After the construction of the supporting structure is completed, a 1.5m wide and 30~50mm thick drainage is made on the top of the slope, and a water retaining edge is built to prevent water from flowing into the foundation pit during rainy days and causing adverse effects on the foundation pit.
[0039] In the structure of the utility model, threaded steel bars are used instead of anchor rods to be arranged in a plum blossom shape. At the same time, a steel mesh and reinforcing ribs are arranged on the slope. The steel mesh is fixed to the slope with a friction anchor U-shaped steel bar clamp. While saving costs, the steel bars replacing the anchor rods, the steel mesh and the slope are connected as one, without occupying the construction area, making the foundation pit more beautiful, improving the stability of the slope and reducing the risk of landslides.
[0040] The above description is only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.
Claims
1. A deep foundation pit support structure for backfilling slag areas in open pits, characterized in that: The deep foundation pit support structure is composed of threaded steel bar soil nails (1) arranged perpendicular to the slope in the foundation pit body, first reinforcing ribs (2), steel mesh (3), second reinforcing ribs (4) and drain pipes (5) formed in one piece by spraying concrete (6); the threaded steel bar soil nails (1) are arranged in a plum blossom shape on the slope, the first reinforcing ribs (2) include first transverse reinforcing ribs (201) and first longitudinal reinforcing ribs (202), and the first transverse reinforcing ribs (201) and the first longitudinal reinforcing ribs (202) are fixedly connected to the threaded steel bar soil nails (1) by welding to form an integral structure; The steel mesh (3) is supported and connected above the threaded steel soil nail (1) through the second reinforcement rib (4), and is fixedly connected to the slope through the friction anchor U-shaped reinforcement clamp, the second reinforcement rib (4) includes a second transverse reinforcement rib (401) and a second longitudinal reinforcement rib (402), and the concrete (6) is arranged above the steel mesh (3); the drainage pipe (5) is arranged in a plum blossom shape on the slope, the outside of the drainage pipe (5) protrudes from the concrete (6), and the inside of the drainage pipe (5) is evenly distributed with a plurality of drainage holes (501), and a fine stone filter bag (502) wrapped with a filter cloth is arranged outside the drainage hole (501).
2. A deep foundation pit support structure for backfilling slag areas in an open pit according to claim 1, characterized in that: The threaded steel bar soil nails (1) and the first reinforcing bar (2) are both made of C16 threaded steel bars.
3. A deep foundation pit support structure for backfilling slag areas in an open pit according to claim 2, characterized in that: The transverse spacing and row spacing of the threaded steel bar soil nails (1) on the slope are both 1500 mm.
4. A deep foundation pit support structure for backfilling slag areas in an open pit according to claim 1, characterized in that: The size of the steel mesh (3) is A6.5@250*250, and the second reinforcing rib (4) is C14 threaded steel bar.
5. A deep foundation pit support structure for backfilling slag areas in an open pit according to claim 4, characterized in that: The overlap width of the steel mesh (3) is not less than 10 cm, and the overlap is fixed with a C16 U-shaped steel bar clip.
6. A deep foundation pit support structure for backfilling slag areas in an open pit according to claim 1, characterized in that: The drainage pipe (5) is made of A75 UPVC pipe. The lateral spacing and row spacing of the drainage pipe (5) on the foundation pit slope are both 3000 mm, and the depth of the drainage pipe (5) is 500 mm. The fine stone filter capsule (502) contains crushed stone with a diameter of 20 mm and gravel or stone chips with a diameter of 1 to 4 mm.
7. A deep foundation pit support structure for backfilling slag areas in an open pit according to claim 1, characterized in that: A construction ramp (12) is provided on one side of the foundation pit body along the upper edge line (7) of the foundation pit to the bottom edge line (8) of the foundation pit, and the remaining area between the upper edge line (7) of the foundation pit and the bottom edge line (8) of the foundation pit is provided as a side slope, the side slope comprising an upper side slope (9) and a lower side slope (10), and a foundation pit middle platform (11) is provided between the upper side slope (9) and the lower side slope (10).
8. The deep foundation pit support structure for backfilling slag areas in an open pit according to claim 1, characterized in that: The slope coefficients of the upper slope (9) and the lower slope (10) are both 1:1, and the slope coefficient of the construction ramp (12) is both 1:
6.
9. The deep foundation pit support structure for backfilling slag areas in an open pit according to claim 1, characterized in that: Drainage ditches (13) are arranged on the top of the upper slope (9), the middle of the platform (11) in the middle of the foundation pit, and the bottom of the lower slope (10).