Flexible permeable debris flow blocking dam
Technical Field
The invention belongs to the technical field of debris flow prevention and control, and particularly relates to a novel debris flow blocking dam body which is particularly suitable for blocking debris flows possibly occurring in areas, such as a tailing pond or an important building, such as a bridge, a railway, a highway and the like, at the upstream of which the debris flows are easy to occur so as to avoid causing damage to the tailing pond or the important building.
Background
The debris flow refers to a mountain area or other gullies and deep ravines, and a region with dangerous terrain, because of the landslide caused by rainstorm, snowstorm or other natural disasters and the special flood flow carrying a large amount of silt and stones, because of the strong impact and silting capabilities, and the characteristics of high abruptness, high flow rate, large material capacity, strong destructive power and the like, serious disasters are often caused in the circulation and accumulation area, and the flow often destroys the traffic facilities such as roads, railways and the like, even villages and towns and the like, so that huge losses are caused.
In order to reduce damage caused by debris flow disasters, debris flow blocking structures are generally arranged in valleys or deep gullies of debris flow regions, and most commonly, the debris flow blocking structures are debris flow blocking dams, which can not only block and store part of debris flow solid-phase substances to reduce the scale of debris flow, but also stabilize the gullies, control channel erosion and inhibit the development of debris flow.
At present, most of common dam body structures are rigid dam structures made of masonry or concrete as main materials. However, although the rigid retaining dam structure has the advantage of high strength, the rigid retaining dam structure is easy to be damaged by impact under the action of strong impact force of debris flow and flows downstream along with the debris flow due to the characteristics of high flow speed, large volume and solid-liquid mixing of the debris flow, so that debris flow disasters can be increased.
In the article of the optimized design of the debris flow retaining dam published in the 2 nd phase of 2009, geological disasters and environmental protection of Chinese journal, a plan view of a typical debris flow retaining dam is disclosed, and as can be seen from the plan view, in order to prevent and treat the damage of upstream debris flow to downstream urban areas, 7 debris flow retaining dams are arranged, so that the construction cost is very high, and the maintenance and the use are inconvenient.
Disclosure of Invention
The invention aims to solve the problems that the existing rigid debris flow blocking dam is easy to be damaged by impact, and the conventional debris flow blocking dam is high in construction cost and inconvenient to maintain and use, and provides a flexible and water-permeable debris flow blocking dam which is used for reducing the impact energy of debris flow, increasing the water permeability of a dam body, smoothly discharging water bodies in debris flow accumulated in front of the dam in a blocking mode, ensuring the safety and stability of the blocking dam and further reducing or eliminating the damage of debris flow.
In order to achieve the purpose, the flexible permeable debris flow blocking dam is realized by adopting the following technical scheme:
the invention relates to a flexible permeable debris flow blocking dam which comprises a stone masonry blocking dam, wherein bottom water drainage openings are formed in the bottom of the stone masonry blocking dam at intervals, and an anti-clogging reinforcing steel bar net piece is arranged at an upstream water inlet of each bottom water drainage opening; dam body water outlet holes are formed in the dam body of the masonry blocking dam at intervals, and the gradient of the dam body water outlet holes is not smaller than 15 degrees; the top drainage piles are arranged at the upper part of the masonry blocking dam at intervals, the arrangement of the drainage piles can increase the drainage capacity of the dam body, and the danger of flood overflowing from the angle of the dam body structure is avoided when the water level is higher; a rigid mesh sheet and gravel flexible water-permeable body is constructed at the middle upper part in the masonry dam body; the bottom water discharge opening, the dam body water discharge hole, the rigid mesh sheet clamped gravel flexible water permeable body and the top water discharge stack jointly form a debris flow blocking dam water discharge system from bottom to top; a flexible anti-collision protective layer formed by a plurality of closely arranged waste tires is arranged on the upstream face of the stone masonry dam, and the elasticity of the rubber tires is utilized to protect the dam body from being directly impacted and damaged; and the bottom of the masonry blocking dam is provided with concrete poured anti-sliding teeth, and the anti-sliding teeth are poured in anti-sliding tooth open grooves dug at the dam feet of the masonry blocking dam.
The rigid mesh piece gravel-sandwiched flexible water permeable body comprises 3 rigid mesh pieces with different rigidity characteristics, the first layer from the upstream surface is a large-specification rigid mesh piece, the second layer from the upstream surface is a medium-specification rigid mesh piece, the third layer from the upstream surface is a small-specification rigid mesh piece, pebble or rock block filling bodies with the block degree of 15-20 cm are filled between the large-specification rigid mesh piece and the medium-specification rigid mesh piece, and pebble or gravel filling bodies with the grain grade of 5-10 cm are filled between the medium-specification rigid mesh piece and the small-specification rigid mesh piece. The flexible water permeable body of the macadam utilizes the holes filled with the macadam to naturally drain water.
The waste tires are hung on anchoring steel bars arranged on the upstream face of the masonry dam. As a flexible anti-collision measure, tires have their own advantages, which are manifested in: the tire is of a round hollow structure, and has good buffering and energy absorbing effects; the arc-shaped structures of the hollow part and the side surface of the tire have small influence on the drain hole of the dam body, and can ensure the smooth drainage operation of the drain hole; the rubber material has stable performance, the waste tire is easy to obtain, and the cost is low.
In order to facilitate the drainage and flood discharge of the dam body and ensure that the downstream subsoil of the dam face of the stone masonry blocking dam is not broken in the drainage and flood discharge processes, a concrete drainage bottom plate is constructed in a natural valley of the downstream dam face of the stone masonry blocking dam, and the concrete drainage bottom plate is connected with anti-sliding teeth poured in anti-sliding tooth open grooves dug at the dam feet of the stone masonry blocking dam into an integral structure.
In order to improve the overall strength of the steel meshes, the middle parts and the upper parts of the large-specification steel meshes, the medium-specification steel meshes and the small-specification steel meshes are fixed by welding channel steel, and each channel steel is directly built in the top of the masonry blocking dam and extends into the dam body of the masonry blocking dam by a certain anchoring depth; the lower parts of the large-specification rigid net sheets, the middle-specification rigid net sheets and the small-specification rigid net sheets are grouted by cement mortar to compact the pores.
In order to ensure the firm combination of the masonry stone blocking dam and the foundation, the groove depth of the anti-sliding tooth grooving groove is not less than 0.5m, and the groove width is not less than 0.5 m.
Theoretical calculation and experimental verification prove that for ensuring effective flood discharge in rainstorm seasons, the specifications and the sizes of the bottom water discharge opening, the dam body water discharge hole and the top water discharge stack are designed as follows: the bottom water outlet is rectangular, the width is 0.3-0.5 m, and the height is 0.4-0.6 m; the horizontal spacing of the dam body water outlet is 0.8-1.2 m, the vertical spacing is 0.8-1.2 m, and the aperture of the dam body water outlet is 70-90 mm; the top drainage stack has a stack height of 0.4-0.7 m and a stack width of 0.35-0.6 m. Test and research results show that the water drainage and flood discharge effects are optimal and debris flow can be effectively blocked by the aid of the specifications and the size design and matching of pebble or block stone filling bodies with the block sizes of 15-20 cm and pebble or broken stone filling bodies with the grain sizes of 5-10 cm respectively filled in the rigid mesh sheet clamped broken stone flexible water permeable bodies.
Theoretical calculations and experimental studies have also determined the optimal technical parameters: the large-size rigid mesh adopts an HBR400 phi 20 steel mesh, and the mesh pitch is 15cm multiplied by 15 cm; the medium-sized rigid mesh adopts an HBR400 phi 16 steel bar mesh, and the mesh pitch is 5cm multiplied by 5 cm; the width of a water discharge opening at the bottom is 0.4m, and the height is 0.5 m; DN80PVC pipes are adopted as the drain holes of the dam body, the horizontal spacing of the drain holes is 1m, and the vertical spacing of the drain holes is 1 m; the top drainage stack had a stack height of 0.5m and a stack width of 0.4 m.
According to the technical scheme of the flexible water-permeable debris flow blocking dam in the structural design of the dam body, the flexibility of the dam body is increased, the impact energy of debris flow can be effectively reduced, the water permeability of the dam body can be improved, water in debris flow accumulated in front of the dam can be smoothly discharged, the safety and stability of the blocking dam are guaranteed, and therefore the damage of debris flow is reduced or eliminated.
After the technical scheme is adopted, the flexible and water-permeable debris flow blocking dam has the following beneficial effects:
(1) the invention arranges the waste tire protective layer on the upstream water surface of the debris flow blocking dam. Under the protection of the elastic action of the tire, the impact force of the debris flow is absorbed, so that the impact force of the solid-liquid mixture of the debris flow directly impacting on the masonry dam body is greatly reduced, the tire covers the upstream surface of the dam body, the influence on the plugging of the bottom water outlet and the water outlet is limited, and the water permeability of the dam body can be ensured.
(2) The invention is beneficial to adjusting the rigidity of the whole dam body by arranging the rigid net sheets on the middle upper part of the dam body to clamp the gravel and the flexible water permeable body, three layers of net sheets with various rigidity characteristics and then clamping the gravel in the middle. The arrangement can increase the flexibility of the dam body, and more absorb the impact force of debris flow on the dam body with larger deformation characteristic; and compared with the original dam body structure, the rigid mesh sheet flexible water permeable body with gravels sandwiched therebetween greatly increases the water permeable capacity, so as to be beneficial to the safety and stability of the dam body.
(3) The invention relates to a flexible permeable debris flow retaining dam combined structure and parameter design, which is a novel dam body structure of a debris flow retaining dam provided for the first time at home and abroad, can play a reference role for the same trip at home and abroad, is applied to similar mountain debris flow treatment engineering projects, and can generate huge social benefits.
Drawings
FIG. 1 is a schematic structural elevation view of a flexible water permeable debris flow barrage according to the present invention;
FIG. 2 is a schematic structural cross-sectional view of a flexible permeable debris flow barrage according to the present invention;
FIG. 3 is a schematic diagram of a rigid mesh-sandwiched gravel flexible water-permeable body adopted at the upper part of a dam body of the flexible water-permeable debris flow retaining dam.
The reference signs are: 1-masonry stone blocking dam; 2-a bottom water discharge opening; 3-discarding the tyre; 4-dam body water drainage holes; 5-top drainage stack; 6-rigid type net piece clamped gravel flexible water permeable body; 7-anti-sliding tooth grooves; 8-concrete drainage bottom plate; 9-large-size rigid mesh sheets; 10-medium size rigid mesh sheet; 11-small gauge rigid mesh; filling 12-15-20 cm pebble or block stones; 13-5-10 cm pebble or gravel filling body.
Detailed Description
For further description of the present invention, a flexible water permeable debris flow barrage according to the present invention will be described in detail with reference to the accompanying drawings and examples.
As shown in fig. 1, the flexible water-permeable debris flow blocking dam of the present invention is shown in a schematic structural elevation view in combination with fig. 2 and fig. 3, and comprises a masonry blocking dam 1, bottom water discharge openings 2 are arranged at the bottom of the masonry blocking dam 1 at intervals, and an upstream water inlet of the bottom water discharge opening 2 is provided with a clogging-preventing reinforcing mesh; dam body water outlet holes 4 are formed in the dam body of the masonry blocking dam 1 at intervals, and the gradient of the dam body water outlet holes 4 is not smaller than 15 degrees; top drainage piles 5 are arranged at intervals on the upper part of the masonry blocking dam 1, pile openings are built evenly and smoothly, and the surfaces of the pile openings are plastered by M10 mortar; a rigid mesh sheet and gravel flexible water-permeable body 6 is constructed at the middle upper part in the body of the stone masonry blocking dam 1. The rigid mesh piece gravel-sandwiched flexible water permeable body 6 comprises 3 rigid mesh pieces with different rigidity characteristics: the first layer from the upstream surface is a large-size rigid mesh 9-phi 20HBR400 steel bar mesh, and the mesh pitch is 15cm multiplied by 15 cm; the second layer from the upstream surface is a middle-specification rigid mesh 10-HBR 400 phi 16 steel bar mesh, and the mesh pitch is 5cm multiplied by 5 cm; the third layer from the upstream surface is a small-sized rigid net sheet 11-
HBR400 phi 8 steel mesh, mesh hole distance is 2cm multiplied by 2 cm. Pebble or block stone filling bodies 12 with the block degree of 15-20 cm are filled between the large-specification rigid net sheets 9 and the medium-specification rigid net sheets 10, pebble or broken stone filling bodies 13 with the grain size of 5-10 cm are filled between the medium-specification rigid net sheets 10 and the small-specification rigid net sheets 11, and filling is required to be naturally filled and compacted in the construction process without vibrating or rolling. The middle parts and the upper parts of the large-specification rigid net sheets 9, the medium-specification rigid net sheets 10 and the small-specification rigid net sheets 11 are fixed through welding channel steel, each channel steel is directly built in the top of the masonry blocking dam 1 and extends into the dam body of the masonry blocking dam 1 for a certain anchoring depth, and the rigid net sheets and the channel steel are subjected to anticorrosion treatment in construction; the lower parts of the large-specification rigid mesh 9, the medium-specification rigid mesh 10 and the small-specification rigid mesh 11 are grouted by M30 cement mortar to compact the pores. The bottom water discharge opening 2 is rectangular, and is 0.4m wide and 0.5m high; DN80PVC pipes are adopted by the dam body water outlet 4, the horizontal distance of the water outlet 4 is 1m, and the vertical distance of the water outlet 4 is 1 m; the stack height of the top drainage stack 5 is 0.5m, and the stack width is 0.4 m; the bottom water outlet 2, the dam body water outlet 4, the rigid mesh sheet-sandwiched gravel flexible water permeable body 6 and the top drainage stack 5 jointly form a debris flow blocking dam drainage system from bottom to top; a flexible anti-collision protective layer consisting of a plurality of closely arranged waste tires 3 is arranged on the upstream face of the masonry blocking dam 1, the waste tires 3 are hung on anchoring steel bars arranged on the upstream face of the masonry blocking dam 1, and the elasticity of rubber tires is utilized to protect a dam body from being damaged by direct impact. The concrete poured anti-sliding teeth 7 are arranged at the bottom of the masonry blocking dam 1, the anti-sliding teeth 7 are poured in anti-sliding tooth open grooves dug by dam feet of the masonry blocking dam 1, the groove depth of the anti-sliding tooth open grooves is not less than 0.5m, and the groove width is not less than 0.5 m. A concrete drainage bottom plate 8 is constructed in a natural valley of the downstream of the dam face of the masonry blocking dam 1, and the concrete drainage bottom plate 8 is connected with anti-sliding teeth 7 poured in anti-sliding tooth grooves dug in dam feet of the masonry blocking dam 1 to form an integral structure.
In the construction process of the dam body of the debris flow masonry dam 1, the flexible anti-collision protective layer formed by the plurality of closely-arranged waste tires 3 is distributed on the upstream water-facing surface of the masonry dam 1, and the rigid net piece clamped gravel flexible water permeable body 6 arranged at the middle upper part of the dam body is used for adjusting and increasing the flexibility of the dam body, absorbing and weakening the impact force of debris flow, has good water permeability, can quickly permeate and discharge water bodies in the debris flow blocking accumulation bodies of the debris flow dam, ensures the safety and stability of the blocking dam, and reduces or eliminates the damage of the debris flow.
The invention is applied to mountain valley areas where debris flow is easy to occur at the upstream of a certain large tailing pond in the south in China, and application results show that the built flexible water-permeable debris flow blocking dam is tested by meeting heavy rain for 500 years, thereby effectively preventing debris flow disasters and ensuring the operation safety of the large tailing pond.