A water-rock separation structure for debris flow prevention in mountainous areas

Abstract

This utility model discloses a water-rock separation structure for debris flow prevention in mountainous areas, comprising a reinforced concrete beam frame, H-shaped steel supports, steel mesh, guide sidewalls, and a bottom spillway structure. The function of this utility model is to filter, screen, and dissipate the mixed flow of water, gravel, and large rocks in the debris flow through the separation effect of the arched water-rock separation corridor. This separates the debris flow into a coarse-particle debris flow and a water flow containing sand and gravel, thus controlling the probability of debris flow occurrence and demonstrating a significant prevention effect. Furthermore, compared to existing prevention technologies, the continuity and integrity of the structure greatly reduce the risk of debris flow collapse, and the separated fluid significantly reduces the impact force of the debris flow blocks and the destructive power of the fluid.

Description

Technical Field

[0001] This utility model patent belongs to the technical field of debris flow prevention devices, specifically relating to a water-rock separation structure for debris flow prevention in mountainous areas. Background Technology

[0002] Debris flows are special types of floods containing large amounts of mud, sand, rocks, and solid materials such as dead grass and trees. They erupt suddenly and are extremely powerful, causing significant casualties and property damage, such as collapsed houses and blocked roads. Yunnan Province is a mountainous region where flash floods and debris flows are frequent. In recent years, debris flows triggered by high-altitude, long-distance landslides have become even more destructive and difficult to prevent.

[0003] Currently, the main approach to debris flow prevention and control involves engineering projects such as interception, diversion, and slope protection to control the replenishment conditions and reduce hydrodynamic conditions, thereby achieving the goal of control. This method requires favorable terrain conditions to implement these projects. For example, interception projects require relatively gentle gully slopes and wide gullies to accommodate large dam reservoirs. However, interception projects are prone to a series of stability and safety hazards, such as dam foundation erosion, dam bypass erosion, and dam failure, and cannot completely eliminate the hazards of debris flows. Diversion projects require relatively straight gully shapes and sufficient scour depth to ensure the stability of the sidewalls. However, diversion projects are prone to foundation erosion, overturning, and collapse of the sidewalls, as well as bottom scour and downcutting. Overall, current traditional prevention and control approaches and technologies can meet the needs of some debris flow prevention and control, but they cannot solve the problem of debris flow prevention and control under special conditions. In cases where the gully is narrow, has a large longitudinal slope, and has many loose and easily activated source bodies upstream, it can easily cause a sudden, devastating disaster.

[0004] In existing technologies, to address the aforementioned challenges, researchers often employ fish-ridge-shaped grid dams for debris flow control. For example, Chinese patent (CN202298575U) discloses a fish-ridge-shaped debris flow water-rock separation system, which innovates the water-rock separation structure by sequentially setting a diversion dam and a fish-ridge-shaped water-rock separation grid dam along the debris flow direction. The ridge line of the water-rock separation grid dam is aligned with the debris flow direction. The diversion dam bears the main load of the debris flow, while the load borne by the water-rock separation grid dam structure is reduced. During operation, the debris flow flows through the diversion dam's inlet to the upper part of the water-rock separation grid dam, where gravity separates the debris flow into water and rocks, causing solid materials to detach from the debris flow path and stagnate on both sides of the gully bed.

[0005] However, this method has its drawbacks: although the diversion dam can withstand the main load of conventional debris flow, the dam loses its function when the debris flow is too large. After the debris flow crosses the dam, it will bury the grid over a large area. The deeper the burial depth, the weaker its infiltration and filtration effect. As the height difference between the front and back of the dam decreases, it loses its effectiveness. Secondly, the grid dam structure is too small and has insufficient impact resistance. It is easily damaged and collapsed by large rocks in the debris flow, thus failing.

[0006] Meanwhile, a debris flow water-rock separation grid dam and water-rock separation system disclosed in Chinese patent (CN109137847B) also has the above-mentioned defects. Moreover, due to its poor overall integrity and uneven local stress, this type of fish spine skeleton will fail after being subjected to a large-scale debris flow, as it will collapse and become blocked due to the impact and destruction at a certain position in the middle. Subsequent debris flows will bury or destroy its structure by uncovering it.

[0007] As described in the prior art, the novel approach utilizes a multi-group debris flow water-rock separation system arranged along the debris flow direction to dissipate energy and separate debris flows. This method is effective in the early stages, but it becomes difficult to clean the accumulated sand and gravel layers on the spillway and the water-rock separation grid dam in the later stages. As siltation increases, the filtration and permeability will inevitably deteriorate, causing the system's separation function to gradually be lost. This approach cannot fundamentally solve the flow pattern and hazard problems of debris flows. Once the interception or separation project becomes unstable and collapses, the resulting amplified effect will cause enormous destructive power and unbearable disasters.

[0008] Therefore, this paper provides a water-rock separation structure for debris flow prevention in mountainous areas. Utility Model Content

[0009] To solve the above technical problems, the utility model provides a water-rock separation structure for preventing and controlling debris flows in mountainous areas. This structure first has sufficient compressive strength, shear resistance, and the ability to resist the impact of boulders. By utilizing the characteristics of fluids, the debris flow fluid with greater power is continuously decomposed and diffused, frictionally dissipated, collided and separated, and screened and filtered above the water-rock separation corridor over a long distance, achieving the separation of soil and water, and water and rock. The large single-block boulders are separated above the corridor, greatly reducing the participation of solid material sources with larger block diameters in debris flow activities. Starting from the fluid characteristics of debris flows, the debris flow that filters large-diameter boulders is transformed into gravel- and sand-containing water flows, and its energy and destructiveness are significantly reduced, and its prevention and control effect is remarkable. At the same time, compared with the existing retaining, drainage, and separation technologies, the strength of the beam frame structure is sufficient to resist its impact and pressure. Through the spatial buffering and energy dissipation of the long-distance corridor, the debris flow staying above is attenuated into a debris flow, and its frictional resistance is greatly increased. The stacking slope of the loose layer will be greatly increased, and the stacking space and accommodation volume along the mainstream direction will be significantly increased. In addition, without the lubrication and buoyancy effects of water, and with the strength and integrity of the corridor structure, the difficulty of restarting and transporting the loose material sources at the bottom of the gully is also greatly increased, prompting the activity intensity of the debris flow gully to gradually decline until it stops.

[0010] To achieve the above technical effects, the utility model is realized through the following technical solutions: A water-rock separation structure for preventing and controlling debris flows in mountainous areas, including a water-rock separation corridor and a discharge chute. The water-rock separation corridor is fixedly arranged across above the discharge chute, and the discharge chute is arranged on the debris flow gully bed. The cross-section of the water-rock separation corridor is in a circular arch shape and is a permeable structure. It includes a beam frame, H-shaped steel, a steel mesh sheet, and a diversion side wall. The beam frame is embedded across and fixed in the bedrock on both sides of the gully or cast integrally with the diversion side wall. The H-shaped steel is pre-buried on the top of the beam frame before pouring. The steel mesh sheet is laid in an arc shape on the top of the corridor and is fixedly connected by connecting with the steel bars pre-buried on the beam frame. The edges of the steel mesh sheet are embedded in the bedrock or connected and fixed with the pre-buried steel bars of the diversion side wall.

[0011] Preferably, the beam frame is cast with reinforced concrete of model C25 or above, and the beam frame can be arranged in two different shapes: overall in a "rice" shape and overall in a "well" shape.

[0012] Preferably, the beam frame further includes a longitudinal top beam, an arched cross beam, a diagonal bracing beam, a bottom connecting beam, and a longitudinal side beam;

[0013] The beam frame arranged in an overall "rice" shape is as follows: The longitudinal top beam is longitudinally arranged on the top of the arched beam frame. The arched cross beam spans across and connects the longitudinal top beam and the bottom connecting beam along the arched cross-section. The diagonal bracing beams are obliquely and staggeredly spanned across and connected to the longitudinal top beam and the bottom connecting beam with the arched cross beam as the center. The bottom connecting beam is arranged at the bottom on both sides of the beam frame, and the overall plane of the beam frame is spread out in a "rice" shape;

[0014] The beam frame with an overall "well" shape is arranged such that the longitudinal top beam is longitudinally disposed at the top of the beam frame, the longitudinal side beams are longitudinally arranged on both sides of the beam frame, the arched cross beam spans across and connects the longitudinal top beam, the longitudinal side beams, and the bottom connecting beam along the arched cross-section of the beam frame, the bottom connecting beam is arranged at the bottom of both sides of the beam frame, and the overall plane layout of the beam frame presents a "well" shape.

[0015] Preferably, in the beam frame structure with an overall "rice" shape, 1 to 2 H-shaped steels are arranged at the maximum span between the arched cross beam and the diagonal bracing beam; they jointly form a support system with the beam frame and, together with the upper steel mesh, bear the impact and scraping effects of debris flow.

[0016] Preferably, the beam frame is arranged in two different channel conditions, specifically including:

[0017] For the first case, when the channel is relatively narrow and meets the corridor span and there are relatively complete and hard bedrocks distributed on both sides of the bank slope, the bedrocks on both sides of the channel are used as the foundation support for the corridor. The longitudinal top beam is arranged at the top of the arched beam frame. When the arched cross beam spans across both sides of the channel and the arch top presents a "rice" shape, the two arched cross beams are connected by a diagonal bracing beam, and after the diagonal bracing beam and the arched cross beam meet, they are embedded into the bedrocks on both sides of the channel, and the corridor is enclosed into a whole structure in the form of a bottom connecting beam; when the arch top presents a "well" shape, the two arched cross beams are connected by a longitudinal side beam, the arched cross beam is embedded into the bedrocks on both sides of the channel, and the corridor is enclosed into a whole structure in the form of a bottom connecting beam.

[0018] For the second case, when there are no complete bedrocks on both sides of the channel and it is loose broken accumulation gravel soil, diversion side walls can be built on both sides of the spillway chute. The longitudinal top beam is longitudinally arranged at the top of the arched beam frame. When the arched cross beam spans across both sides of the channel and the arch top presents a "rice" shape, the two arched cross beams are connected by a diagonal bracing beam, and the intersection of the diagonal bracing beam and the arched cross beam is integrally poured with the diversion side wall to form an integral structure; when the arch top presents a "well" shape, the two arched cross beams are connected by a longitudinal side beam, and the arched cross beam is integrally poured with the diversion side wall to form an integral structure.

[0019] Preferably, the spillway chute is paved at the bottom with high-performance wear-resistant concrete of C25 or above, and the bottom is made into a "V" shape, and a super-elevation reverse slope section is provided at the bend to restrain the water flow; preventing it from scouring the diversion side wall or the weathered layer of the bedrock.

[0020] Preferably, the steel mesh is welded into a circular arch shape using HRB400ф32 type steel bars, is fully paved on the top of the corridor close to the beam frame, and is fixed by connecting with the steel bars embedded in the beam frame, and is fixed with the steel bars embedded in the diversion side wall or the bottom connecting beam at both bottom sides.

[0021] Preferably, the steel bar mesh also includes two different planar spreads. When the beam frame is in a "rice" shape structure, the steel bar mesh is made into a diamond structure to match it; when the beam frame is in a "well" shape structure, the steel bar mesh is made into a rectangular structure to match it.

[0022] The beneficial effects of the present utility model are as follows:

[0023] This structure first has sufficient compressive capacity, shear resistance and impact resistance against block stones. Utilizing the characteristics of the fluid, the debris flow fluid with greater power is continuously decomposed, diffused, frictionally dissipated, collision-separated and screened-filtered above the water-rock separation corridor over a long distance, realizing the separation of soil and water, and water and stones. The large single-block boulders are separated above the corridor, greatly reducing the participation of solid material sources with larger block diameters in debris flow activities. This method can start from the fluid characteristics of debris flow, filtering the debris flow with large boulders into a gravel- and sand-containing water flow, and its energy and destructiveness are significantly reduced, and its prevention and control effect is remarkable. At the same time, compared with the existing retaining, drainage and separation technologies, the strength of the beam frame structure is sufficient to resist its impact and pressure. Through the spatial buffering and energy dissipation of the long-distance corridor, the debris flow staying above is attenuated into a debris flow, and its frictional resistance is greatly increased. The stacking slope of the loose layer will be greatly increased, and the stacking space and accommodation volume along the mainstream direction will be significantly increased. In addition, without the lubrication and buoyancy effects of water, and with the strength and integrity of the corridor structure, the difficulty of restarting and transporting the loose material source at the bottom of the gully is also greatly increased, prompting the activity intensity of the debris flow gully to gradually decline until it stops;

[0024] The governance concept of the present utility model for debris flow is to fully consider the fluid characteristics of debris flow, adhere to the principle of "adjusting measures to local conditions", and make full use of the natural gully and the water-rock separation corridor to jointly form the overall compressive and impact resistance. Utilize the diffusing and energy-dissipating of the longitudinal top beam, the compressive and impact resistance of the circular-arch reinforced concrete structure, the surface frictional energy dissipation of the HRB400 deformed steel bars and the water permeability of the mesh. And the long-distance continuous action of the corridor enables the debris flow fluid to be fully dissipated, impacted and frictionally dissipated. Due to the differences in its density, viscosity, etc., the solid-liquid mixed flow has different directions after collision, meeting the basic conditions for separation. After its energy is reduced, it is sorted and filtered, separating the water-rock and soil-water mixed flow into a debris flow mainly composed of large boulders and a mixed flow mainly composed of fine particles such as sand and gravel. The sand- and gravel-containing water flow passing through the steel bar mesh at the top of the corridor reaches the discharge chute in a diffused state, and is drained to the downstream outside the corridor area under the drive of the water flow and the acceleration of the terrain;

[0025] In the section with a relatively steep longitudinal slope, it is difficult for the corridor to form accumulations due to the terrain acceleration and the diversion effect of the longitudinal main beam. Instead, a relatively concentrated separation and filtration area will be formed. The lower discharge chute also has good flow-through performance due to the relatively steep terrain. In the section with a relatively gentle longitudinal slope, accumulations will first stop in the narrow areas on both sides of the longitudinal main beam and gradually form a loose accumulation layer that is thicker at the bottom and thinner at the top. Its water filtration and sorting properties will deteriorate. After losing the effect of water, the friction between solid coarse particles will increase significantly, reducing the fluidity of the solid loose layer and increasing the difficulty of initiating sediment transport at the bottom of the gully. Along this section, it is easy to form imbricate accumulations extending upstream. When the overall extension of the corridor is long enough and the terrain is relatively steep, there is enough space for screening and filtration, making it easy to achieve sufficient separation of water and stones, fundamentally reducing the energy and destructive power of debris flows, and the prevention and control effect is remarkable. At the same time, the engineering structure has good integrity and stability. Even if accumulations form over time, the difficulty of initiating sediment transport at the bottom of the gully will increase significantly. Compared with the existing retaining technologies that are prone to collapse and pose a huge risk of "accumulating in small amounts and releasing in large amounts" under extreme working conditions, the engineering reliability has been greatly improved; [[ID=②]]

[0026] Moreover, the beam frame of the corridor extends downstream as a whole. The top of the corridor is generally used to dissipate the energy of the debris flow fluid in a "smooth" manner rather than resisting it. This structure has sufficient spatial ductility. At the same time, by fully utilizing the friction performance of the surface of the deformed steel bars and the steel mesh, it can better dissipate the energy of the debris flow fluid, allowing the debris flow to dissipate energy by "exchanging space for time". The corridor is an arched structure with sufficient compressive strength, shear resistance, and resistance to block impact. The solid loose materials accumulated on the top of the corridor will form an arching effect under the action of increasing thickness and long-term water penetration force. The arch gradually replaces the concrete arched structure in bearing the load, ensuring the long-term sufficient stability and safety of the corridor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Without creative efforts, those skilled in the art can also obtain other drawings based on these drawings:

[0028] Figure 1 Structural diagram of the "cross" - shaped corridor with diversion side walls of the present invention;

[0029] Figure 2 Structural diagram of the "grid" - shaped corridor with diversion side walls of the present invention;

[0030] Figure 3 Structural diagram of the "cross" - shaped corridor without diversion side walls of the present invention;

[0031] Figure 4 Structural diagram of the "grid" - shaped corridor without diversion side walls of the present invention;

[0032] Figure 5 Top view schematic diagram of the "rice" - shaped corridor with diversion side walls of the present utility model;

[0033] Figure 6 Top view schematic diagram of the "grid" - shaped corridor with diversion side walls of the present utility model;

[0034] Figure 7 Top view schematic diagram of the "rice" - shaped corridor without diversion side walls of the present utility model;

[0035] Figure 8 Top view schematic diagram of the "grid" - shaped corridor without diversion side walls of the present utility model;

[0036] Figure 9 Cross - sectional schematic diagram of the "rice" - shaped corridor with diversion side walls of the present utility model;

[0037] Figure 10 Cross - sectional schematic diagram of the "grid" - shaped corridor with diversion side walls of the present utility model;

[0038] Figure 11 Cross - sectional schematic diagram of the "rice" - shaped corridor without diversion side walls of the present utility model;

[0039] Figure 12 Cross - sectional schematic diagram of the "grid" - shaped corridor without diversion side walls of the present utility model;

[0040] Figure 13 Calculation sketch of the corridor in Embodiment 3 of the present utility model;

[0041] Figure 14 In Embodiment 3 of the present utility model, the gravity and overall impact force of the debris flow acting on the rib beams (including arch cross - beams, diagonal braces, and longitudinal side beams) are generalized as uniformly distributed loads in the adverse case;

[0042] Figure 15 Overall impact force of the debris flow acting on the corridor in Embodiment 3 of the present utility model;

[0043] Figure 16 Schematic diagram of the impact force of large boulders acting on the corridor in Embodiment 3 of the present utility model;

[0044] In the attached drawings, the list of components represented by each reference numeral is as follows:

[0045] 1. Longitudinal top beam; 2. Arch cross - beam; 3. Diagonal brace; 4. Bottom connection beam; 5. Diversion side wall; 6. Drainage channel; 7. Steel mesh; 8. H - shaped steel; 9. Longitudinal side beam. Detailed implementation manners

[0046] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model. Example 1

[0047] like Figures 1 to 4 As shown, the prior art in this embodiment has the following problems: The inventor found that the prior art also has defects: the load-bearing capacity of the rib-shaped fish spine skeleton cannot meet the requirements, and it is very easy to be damaged and collapse by large rocks in the debris flow; this type of water-rock separation barrier dam can achieve a more obvious water-rock separation effect in the early stage of use, but after a period of use, the accumulation of too much loose soil and rocks that are difficult to clean will reduce or even eliminate the water-rock separation performance of the dam body. Even if multiple sets of debris flow water-rock separation systems are used to dissipate energy and separate debris flows, this method is only effective in the early stage.

[0048] Therefore, the utility model provides a water-rock separation structure for debris flow prevention in mountainous areas, including a water-rock separation corridor and a spillway 6. The water-rock separation corridor is fixedly installed across the top of the spillway 6, and the spillway 6 is installed on the debris flow gully bed. The water-rock separation corridor has a circular arched cross-section and a permeable structure, including a beam frame, H-beams 8, steel mesh 7, and a guide wall 5. The beam frame is embedded in the bedrock on both sides of the gully bed or cast integrally with the guide wall 5. The H-beams 8 are pre-embedded in the top of the beam frame before casting. The steel mesh 7 is laid in an arc shape on the top of the corridor and is connected and fixed by the steel bars pre-embedded in the beam frame. The edges of the steel mesh 7 are embedded in the bedrock or connected and fixed to the pre-embedded steel bars in the guide wall 5.

[0049] Its effects and principles are as follows: The utility model fully analyzes the fluid characteristics of debris flow, fully considers "adapting measures to local conditions", utilizes the comprehensive effect of natural channels and water-rock separation corridors to form an organic whole, and makes full use of the performance of the materials and structures of the water-rock separation corridors. Under the continuous action of the debris flow fluid in the corridor over a long distance, the debris flow fluid is fully dissipated, impacted, and its energy is dissipated through friction. After the solid-liquid mixed flow is impacted, due to the differences in its density, viscosity, etc., the basic conditions for separation are met, and then sorting and filtering are carried out to separate the water-rock and water-soil mixed flows into a debris flow mainly composed of large boulders and a mixed flow mainly composed of fine particles such as sand and gravel. The water flow containing gravel and sand passes through the steel mesh 7 at the top of the corridor to form a dispersed flow and enters the interior of the corridor, and then is collected and discharged through the drainage trough 6 at the bottom of the corridor, and the water flow containing sand and gravel is discharged to the downstream channel outside the corridor. In the section with a relatively steep longitudinal slope, it is difficult for the corridor to form a deposit due to the terrain acceleration and the diversion effect of the longitudinal main beam, and a relatively concentrated separation and filtration area will be formed. The lower drainage trough 6 also forms a good flow channel due to the relatively steep terrain; in the section with a relatively gentle longitudinal slope, it will first stop and accumulate in the narrow areas on both sides of the longitudinal main beam, gradually forming a loose accumulation layer with coarser particles at the bottom and finer particles at the top. Its water filtration and sorting properties will deteriorate. After losing the effect of water, the friction between solid coarse particles will be greatly increased, reducing the fluidity of the solid loose layer, increasing the difficulty of starting transportation at the bottom of the ditch, and it is easy to form an imbricate accumulation extending upstream along this section. When the overall water-rock separation corridor is long enough and the terrain is relatively steep, there is enough space for screening and filtering, with sufficient water-rock separation space, fundamentally reducing the energy and destructiveness of debris flow. At the same time, the overall structure formed by connecting the beam frames and the steel mesh 7 has good integrity and stability, and the engineering reliability is greatly improved; and the beam frames of the corridor are distributed downstream as a whole, and at the same time, the friction effect of the surface of the threaded steel bars and the steel mesh 7 is fully utilized, which can better dissipate the energy of the debris flow fluid. The top of the water-rock separation corridor as a whole dissipates the energy of the debris flow fluid in a "smooth" manner, rather than resisting it. This structure has sufficient space ductility to ensure long-term sufficient stability and safety. Its overall prevention and control effect is remarkable.

[0050] Furthermore, the beam frames are cast with reinforced concrete of model C25 or above. The beam frames can be arranged in two different shapes: the first is in an overall "cross" shape, and an H-shaped steel 8 is set at the large-span position in the middle of the beam frame to play a role in densifying the beam frame, fixing the steel mesh 7, and transmitting and bearing forces; the second is in an overall "grid" shape, and three longitudinal beams are arranged parallel to the ditch, and together with the arched cross beam 2, they play a role in supporting and bearing forces and fixing the steel mesh 7.

[0051] This structure is arched, which can give full play to the overall compressive capacity of reinforced concrete and can better transfer the force of the longitudinal top beam 1 laterally to the corridor foundation. The soil arch effect formed by the arched corridor greatly increases the stability of the corridor. Therefore, the beam frame system has sufficient compressive capacity, shear resistance and anti-block impact capacity.

[0052] Furthermore, the beam frame further includes a longitudinal top beam 1, an arched cross beam 2, a diagonal bracing beam 3, a bottom connecting beam 4, and a longitudinal side beam 9;

[0053] The beam frame with an overall "rice" shape is arranged as follows: the longitudinal top beam 1 is longitudinally arranged at the top of the arched beam frame, the arched cross beam 2 spans across and connects the longitudinal top beam 1 and the bottom connecting beam 4 along the arched section, the diagonal bracing beam 3 is obliquely and staggeredly spanned across and connects the longitudinal top beam 1 and the bottom connecting beam 4 with the arched cross beam 2 as the center, the bottom connecting beam 4 is arranged at the bottom on both sides of the beam frame, and the overall plane layout of the beam frame is in the shape of a "rice" character;

[0054] The beam frame with an overall "well" shape is arranged such that the longitudinal top beam 1 is longitudinally arranged at the top of the beam frame, the longitudinal side beam 9 is longitudinally arranged on both sides of the beam frame, the arched cross beam 2 spans across and connects the longitudinal top beam 1, the longitudinal side beam 9, and the bottom connecting beam 4 along the arched section of the beam frame, the bottom connecting beam 4 is arranged at the bottom on both sides of the beam frame, and the overall plane layout of the beam frame is in the shape of a "well" character.

[0055] The longitudinal top beam 1 in this structure is the main longitudinal stress-bearing beam at the top of the corridor, which mainly functions to disperse the debris flow fluid, disintegrate the "head" of the debris flow, change the flow direction of the debris flow, and reduce the energy of the debris flow; the arched cross beam 2 is the main transverse stress-bearing beam of the corridor, which can provide support for the corridor and the accumulated solid loose material accumulation layer thereon; the longitudinal side beam 9 is a secondary stress-bearing beam, which can enhance the integrity of the "corridor" and support the steel mesh 7, and the diagonal bracing beam 3 is a force-transferring beam, and the inclination angle of the diagonal bracing beam 3 can be set according to the size of the longitudinal slope of the gully, which mainly functions to conduct the horizontal impact force of the debris flow from the longitudinal top beam 1 to the bottom connecting beam 4 or the diversion side wall 5 at the lower end; when the arched cross beam 2 is supported in the relatively complete and hard bedrock on both sides of the bank slope and the gully is relatively narrow, the bottom connecting beam 4 is arranged at the bottom on both sides of the corridor to enhance the integrity. When there is loose broken gravel soil without complete bedrock on both sides of the gully, diversion side walls 5 can be built on both sides of the discharge chute 6, and the diversion side walls 5 are integrated with the arched cross beam 2, and the bottom connecting beam 4 does not need to be built separately in this structure.

[0056] Furthermore, in the beam frame structure with an overall "rice" shape, 1 to 2 H-shaped steels 8 are arranged at the maximum span between the arched cross beam 2 and the diagonal bracing beam 3; they jointly form a support system with the beam frame and承受泥石流的冲击、铲刮作用 together with the upper steel mesh 7.

[0057] Furthermore, the beam frame is arranged in two different gully conditions, specifically including:

[0058] For the first case, when the channel is relatively narrow, the span of the corridor is satisfied, and there are relatively complete and hard bedrocks distributed on both sides of the slope, the bedrocks on both sides of the channel are used as the foundation support of the corridor. The longitudinal top beam 1 is arranged at the top of the arched beam frame. When the arched cross beam 2 spans both sides of the channel and the arch top is in the shape of a "rice" character, the inclined strut beam 3 is used to connect between the two arched cross beams 2. After the inclined strut beam 3 and the arched cross beam 2 meet, they are embedded in the bedrocks on both sides of the channel, and the bottom connecting beam 4 is used to enclose the corridor into an integral structure. When the arch top is in the shape of a "well" character, the longitudinal side beam 9 is used to connect between the two arched cross beams 2. The arched cross beam 2 is embedded in the bedrocks on both sides of the channel, and the bottom connecting beam 4 is used to enclose the corridor into an integral structure.

[0059] For the second case, when there is no complete bedrock on both sides of the channel and it is loose broken accumulated gravel soil, the diversion side walls 5 can be built on both sides of the discharge chute 6. The longitudinal top beam 1 is longitudinally arranged at the top of the arched beam frame. When the arched cross beam 2 spans both sides of the channel and the arch top is in the shape of a "rice" character, the inclined strut beam 3 is used to connect between the two arched cross beams 2. The intersection of the inclined strut beam 3 and the arched cross beam 2 and the diversion side wall 5 are integrally cast to form an integral structure. When the arch top is in the shape of a "well" character, the longitudinal side beam 9 is used to connect between the two arched cross beams 2. The arched cross beam 2 and the diversion side wall 5 are integrally cast to form an integral structure.

[0060] Furthermore, the discharge chute 6 is paved at the bottom with high-performance wear-resistant concrete of C25 or above C25, and the bottom is made into a "V" shape. An ultra-high reverse slope section is set at the bend to restrain the water flow, preventing it from scouring the diversion side wall 5 or the weathered layer of the bedrock.

[0061] The design of this structure can increase the erosion resistance of the bottom of the channel. At the same time, the "V" shape can divert and restrain the sand-containing water flow inside the channel, avoiding the side erosion of the two side slopes, increasing the water flow velocity, and discharging the gravel, sand and water passing through the top of the corridor to the downstream area outside the corridor without blocking the corridor.

[0062] Furthermore, the steel mesh 7 is welded into a circular arch shape with HRB400 ф32 type steel bars, closely paved on the top of the beam frame, and fixed by connecting with the steel bars embedded in the beam frame. The two sides at the bottom are fixed with the steel bars embedded in the diversion side wall 5 or the bottom connecting beam 4.

[0063] Furthermore, the steel mesh 7 also includes two different plane spreads. When the beam frame is in the "rice" character structure, the steel mesh 7 is made into a diamond structure to match it. When the beam frame is in the "well" character structure, the steel mesh 7 is made into a rectangular structure to match it.

[0064] The structure is designed to fully cover the top of the corridor, which can make full use of the strong friction performance of the HRB400 threaded steel bar surface and make good use of the ductility of the steel bar in local tensile and bending resistance. It can effectively dissipate the energy of the debris flow and prevent it from being destroyed by the debris flow. The steel mesh 7 acts as a "sieve" to block large and release small stones, stopping large floating stones at the top of the corridor. Gravel and sand-containing water flows into the corridor through the mesh. At the same time, the steel bars pre-embedded in the beam frame are fixed by hooks or welding.

[0065] It should be understood that when the engineering geological conditions of both bank slopes can meet the stress requirements of the corridor, there is no need to construct the diversion sidewall 5 as the foundation of the corridor, so the utility model retains this solution. Example 2

[0066] Based on the above technical solution, the utility model is realized in the following ways:

[0067] First, based on historical meteorological data, determine the peak flow of the rainstorm, the peak flow of the debris flow, the flow velocity, the characteristics of the debris flow basin, the source conditions, the total source amount, the amount of source material that can participate in the debris flow, the distribution location of the main sources participating in the debris flow and the way they participate in the debris flow, the amount of source material ejected in a single debris flow, the total amount of solid material ejected by the debris flow, the impact force of the debris flow, and the impact force of large rocks.

[0068] Next, the cross-section of the corridor is determined based on the debris flow rate and velocity to ensure that the corridor has sufficient flow cross-section; the weight of the solid material accumulated at the top of the corridor is determined based on the amount of solid material ejected from the debris flow and the amount of debris flow source material that can participate; the cross-sectional size of the main load-bearing beams of the corridor, the strength of the H-beams 8, and the spacing of their arrangement are determined based on the weight of the accumulated solid material, the impact force of the debris flow, and the impact force of large rocks; the mesh size of the steel mesh 7 is determined based on the content and size of solid particles in the debris flow fluid.

[0069] Then, by performing structural mechanics calculations on the water-rock separation corridor, it is ensured that the main load-bearing beams have sufficient compressive strength, shear strength, and resistance to rock impact. The inclination angle of the inclined bracing beam 3 is set according to the longitudinal slope of the channel to ensure the overall stability of the corridor. The paving thickness of the spillway 6 and the strength of the wear-resistant concrete are determined according to the geological and hydrodynamic conditions at the bottom of the channel. The foundation depth of the diversion sidewall 5 is determined by the geological conditions at the bottom of the channel, or the embedment depth of the arched crossbeam 2 and the inclined bracing beam 3 is determined by the integrity and weathering degree of the bedrock on both sides of the bank slope to ensure the foundation stability of the corridor.

[0070] Finally, it is important to note that the span of the water-rock separation corridor should not be too large to ensure sufficient stability. The arch curvature of the corridor should not be too gentle; the corridor should be made approximately semi-circular to form a compression structure, fully utilizing the compressive strength of the concrete. The longitudinal top beam 1 is the main load-bearing beam, acting as the "head" for disintegrating debris flows. After solid loose material accumulates at the top, it becomes the main load-bearing component, and its cross-section must meet the requirements of structural integrity and safety. The guide walls 5 on both sides of the corridor should have sufficient support capacity and resistance to lateral erosion, utilizing the foundation bearing capacity to ensure the overall stability of the corridor. The spillway 6 should have sufficient wear resistance to ensure long-term stable operation without being cut off by the undercut. Example 3

[0071] like Figures 13 to 16 As shown, based on the above embodiments, the utility model provides a case study of applying the key technology (water-rock separation corridor) of the water-rock separation method for debris flow prevention in mountainous areas to the upper and middle sections of the C30 gully, Z1 tributary, and Lanlin River main channel in the Tiejia River basin of Eryuan County, Dali Prefecture, Yunnan Province:

[0072] This project involved constructing an 18.0m long LD1 water-rock separation corridor at the starting section of the C30 gully in the upper reaches of the Heilong River. This corridor is used to manage the source of the active gully upstream of the debris flow, filtering and draining loose material sources such as landslides at the gully source, and stabilizing these sources at the gully source and on both sides, thereby achieving the goal of gully management. A 47.2m long LD2 water-rock separation corridor was constructed in the middle and lower section of the Z1 tributary. This corridor controls and impedes loose material sources such as landslides on both sides of the gully. It fully utilizes the arched structure of the corridor to stabilize larger landslides on both sides of the gully, preventing further collapse and expansion of these loose materials and blocking their entry into the gully bed to participate in debris flow. The permeability of the corridor allows water from loose material sources such as landslides to drain out, while allowing upstream debris flows or sand-laden water to pass through the discharge channel 6 at the bottom of the corridor. This also controls the scraping and cutting action of upstream debris flows or sand-laden water on this section, thus achieving the goal of managing this section of the gully. A 420.54m long LD3 water-rock separation corridor was constructed in the upper and middle section of the main gully of the Lanlin River. This corridor utilizes the favorable natural gully bed and sufficient length to separate water and rocks from debris flows from upstream, reducing the threat of potential chain disasters of landslides and debris flows from upstream. It separates large boulders, boulders, and water flows containing gravel and sand, while also playing a role in energy dissipation and force reduction, stabilizing the gully bed and banks, and mitigating debris flows, thereby achieving the goal of managing this section of the gully.

[0073] LD1 Water-Stone Separation Corridor: 18.0m long, with a longitudinal top beam of 150cm wide * 50cm high, an arched crossbeam of 240cm wide * 50cm high every 5.6m, a diagonal bracing beam of 340cm wide * 50cm high, and a guide wall 5 3.0m high, 72cm wide at the top, and 1.2m wide at the bottom. At the large span between the longitudinal top beam 1 and the diagonal bracing beam 3, 20A100*100*6*8 H-beams 8 are laid on the top of the corridor, extending at least 0.2m into the connecting beam. A diamond-shaped steel mesh 7 composed of HRB400φ32 steel bars is laid on the top of the corridor and the steel sections, with vertical spacing of 0.5m and the bars extending at least 0.2m into the guide walls 5 on both sides. A drainage channel 6 is installed at the bottom of the corridor, with C25 wear-resistant concrete used for the bottom paving. The drainage channel 6 has a "V" shaped cross section and a thickness of 0.4m. An expansion joint is installed at every interval of an arched crossbeam 2 (12m) along the longitudinal top beam 1. The soil and rock in this area are fractured, with a large thickness of loose material, developed landslides in the source area, and strong gully activity. The overall size of the broken stones is small. Therefore, APS-100(RN) / P protective netting is used to completely cover the upper part of the steel mesh 7 at the top of the corridor to densify the pores of the diamond-shaped steel mesh 7.

[0074] LD2 Water-Stone Separation Corridor: 47.20m long, with a longitudinal top beam of 160cm wide x 60cm high, an arched crossbeam of 250cm wide x 60cm high every 6m, a diagonal bracing beam of 350cm wide x 60cm high, and a guide wall 5 2.2m high, 85cm wide at the top, and 1.09m wide at the bottom. At the large span between the longitudinal top beam 1 and the diagonal bracing beam 3, 20A100*100*6*8 H-beams 8 are laid on the top of the corridor, extending at least 0.2m into the connecting beam. A diamond-shaped steel mesh 7 composed of HRB400 φ32 steel bars is laid on the top of the corridor and the steel structure, with vertical spacing of 0.6m and the bars extending at least 0.2m into the guide walls 5 on both sides. A drainage channel 6 is installed at the bottom of the corridor. C25 wear-resistant concrete is used to pave the bottom. The cross-section of the drainage channel 6 is a gentle "V" shape with a thickness of 0.4m. An expansion joint is set every 13m along the longitudinal top beam 1 with an arched crossbeam 2. The soil and rock in this area are broken, and landslides are developed on both sides of the ditch. The debris flow has formed a large free face, and the landslide body can directly reach the ditch bed and participate in the debris flow. The overall size of the broken stones is relatively small. Therefore, APS-100(RN) / P protective netting is used to cover the upper part of the steel mesh 7 at the top of the corridor to densify the pores of the diamond steel mesh 7.

[0075] LD3 Water-Stone Separation Corridor: 420.54m long, with a longitudinal top beam of 1100cm wide x 100cm high, an arched crossbeam of 280cm wide x 100cm high every 5.8m, longitudinal side beams of 960cm wide x 100cm high, a bottom connecting beam of 440cm wide x 50cm high, and a guide wall 5 4.0m high, with a top width of 1.33m and a bottom width of 2.41m. The overall planar layout of the corridor's beams is in a "well" shape, with longitudinal top beam 1, longitudinal side beams 9, arched crossbeams 2, and bottom connecting beams 4. Guide walls 5 are installed in sections according to the engineering geological conditions of both banks. The top of the corridor is covered with a rectangular steel mesh 7 composed of HRB400 φ32 steel bars, with vertical spacing of 0.4m. The steel mesh 7 extends at least 0.2m into the bottom connecting beams 4 and guide walls 5 on both sides. The sections at KO+86.60-KO+125.40 and KO+317.60-KO+402.60 along the corridor are characterized by large-scale landslides on the bank slope. The landslide debris consists of small-sized stones with a high soil content. Therefore, APS-100(RN) / P protective netting was laid on the top of the corridor at these two locations to densify the mesh size of the reinforcing steel mesh 7. A drainage channel 6 was installed at the bottom of the corridor, with C25 wear-resistant concrete used for the bottom paving. The drainage channel 6 has a gently sloping "V" shape and a thickness of 0.4m. An expansion joint is installed at every 12m interval between the longitudinal top beam 1 and an arched crossbeam 2.

[0076] Calculation parameters: To simplify the calculation, the connection points of the longitudinal top beam 1, arched crossbeam 2, and longitudinal side beam 9 are simplified to hinged joints, and the constraint between the arched crossbeam 2 and the bottom connecting beam 4 is simplified to hinged supports, making it a statically determinate structure. Meanwhile, corridors are generally small-span structures, and the corridor grid mainly bears vertical loads. Therefore, the vertical deformation of the corridor grid can be mainly considered, while the lateral deformation at the impact point can be ignored, thus simplifying the grid into a planar structure. Each rib beam (including the arched crossbeam 2, the diagonal bracing beam 3, and the longitudinal side beam 9) is analyzed separately. The simplified calculation diagram of the corridor is as follows: Figure 13 As shown.

[0077] The beams of the corridor will be mainly subjected to vertical loads such as the gravity of the debris flow, the vertical pressure of the loose sediment on the top of the corridor, the impact force of large rocks in the debris flow, and the impact pressure of the debris flow.

[0078] (1) Gravity of mud and debris fluid, vertical pressure of loose sediment on the top of the corridor

[0079] Gravity of debris flow: Assume the debris flow rushes down from upstream, is uniformly distributed along the longitudinal length of the top beam 1, and the flow depth remains the overflow depth when the debris flow passes through the overflow outlet. Since the debris flow will quickly pass through or slide off the gallery grid as it moves on the gallery, the debris flow moving along the surface of the gallery grid can be ignored. That is, the gravity of the debris flow on the arched beam 2 can be simplified to the distributed load (as shown in Figure 14):

[0080] Its load intensity can be calculated using the following formula:

[0081] W=hd*rd

[0082] Where hd is the design overflow thickness (m), and rd is the design overflow unit weight (kN / m³). 3 );

[0083] Vertical pressure of silt deposits on the tunnel roof: The silt deposits are piled up to a height of 10m as the earth pressure calculation height on the tunnel roof. Simplified to a vertical linear load, the vertical pressure of the silt deposits on the rib beams can be simplified as follows: Figure 2 The load intensity of the distributed load shown can be calculated using the following formula:

[0084] qi=kγdi

[0085] qi — Vertical pressure of backfilled soil and rock at any point on the tunnel roof (KN / m) 2 );

[0086] k — Design safety factor, taken as 1.1;

[0087] γ — Unit weight of the deposit (gravelly soil), taken as 21.5 KN / m 3 ;

[0088] di——Calculate the height of the soil column at point i (m);

[0089] (2) Calculation of debris flow impact force

[0090] 1) Overall impact force of debris flow

[0091] The debris flow impact force calculation formula in the "Specification for Investigation of Debris Flow Disaster Prevention Engineering" (DZ / T 0220-2006) is adopted:

[0092] ;

[0093] The overall impact force of mud and rock fluid borne by the beam frame can be simplified as (e.g.) Figure 15 The distributed load (as shown) is generalized to a uniformly distributed load under unfavorable conditions (e.g., ...). Figure 14 (As shown). The stress-bearing surface of the building is perpendicular to the direction of the debris flow impact; a circular building is used to calculate the overall impact force of the debris flow.

[0094] 2) Calculation of impact force of large rocks in debris flows

[0095] According to the "Specification for Investigation of Debris Flow Disaster Prevention Engineering" (DZ / T 0220-2006), the impact force of large rocks (such as...) Figure 16 As shown), its calculation formula is:

[0096] ;

[0097] Based on the above calculation parameters and formulas, the structural mechanics of the water-rock separation corridor were verified to ensure that the main load-bearing beams have sufficient compressive strength, shear strength, and resistance to rock impact. This allows for the control of the debris flow source, transforming it into a gravel and sand-laden water flow, fundamentally reducing its energy and destructiveness, resulting in significant prevention and control effects. Simultaneously, it addresses the challenges posed by current technology, such as narrow channels, steep longitudinal slopes, and the presence of high-level landslide sources upstream that are inaccessible under conventional construction conditions. The corridor's beam frame possesses sufficient compressive strength, shear strength, and resistance to rock impact, exhibiting good overall stability.

[0098] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0099] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A water-rock separation structure for debris flow prevention in mountainous areas, comprising a water-rock separation corridor and a spillway, wherein the water-rock separation corridor is fixedly installed across the top of the spillway, and the spillway is installed on the debris flow gully bed, characterized in that: The cross-section of the water-rock separation corridor is circular-arch shaped and a permeable structure, which includes a beam frame, H-shaped steel, a steel mesh, and a diversion side wall. The beam frame spans and is embedded in the bedrock on both sides of the gully bed or is cast integrally with the diversion side wall. The H-shaped steel is embedded in the top of the beam frame before casting. The steel mesh is laid in an arc shape on the top of the corridor and is connected and fixed by connecting with the steel bars embedded in the beam frame. The edges of the steel mesh are embedded in the bedrock or connected and fixed with the embedded steel bars of the diversion side wall.

2. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 1, characterized in that: The beam frame is cast with reinforced concrete of model C25 or above, and the beam frame can be arranged in two different shapes, namely, the overall shape of "rice" character and the overall shape of "well" character.

3. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 1, characterized in that: The beam frame further includes a longitudinal top beam, an arched cross beam, a diagonal brace beam, a bottom connecting beam, and a longitudinal side beam. The beam frame with the overall shape of "rice" character is arranged as follows: the longitudinal top beam is longitudinally arranged on the top of the arched beam frame, the arched cross beam spans across and connects the longitudinal top beam and the bottom connecting beam along the arched cross-section, the diagonal brace beams are obliquely and staggeredly spanned across and connected to the longitudinal top beam and the bottom connecting beam with the arched cross beam as the center, the bottom connecting beam is arranged at the bottoms on both sides of the beam frame, and the overall plane layout of the beam frame is in the shape of "rice" character. The beam frame with the overall shape of "well" character is arranged as follows: the longitudinal top beam is longitudinally arranged on the top of the beam frame, the longitudinal side beams are longitudinally arranged on both sides of the beam frame, the arched cross beam spans across and connects the longitudinal top beam, the longitudinal side beams, and the bottom connecting beam along the arched cross-section of the beam frame, the bottom connecting beam is arranged at the bottoms on both sides of the beam frame, and the overall plane layout of the beam frame is in the shape of "well" character.

4. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 3, characterized in that: In the beam frame structure with the overall shape of "rice" character, 1 to 2 H-shaped steels are arranged at the place with the largest span between the arched cross beam and the diagonal brace beam; they jointly form a support system with the beam frame and, together with the upper steel mesh, bear the impact and scraping effects of debris flow.

5. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 1, characterized in that: The beam frame is arranged according to two different gully conditions, specifically including: First, when the gully is relatively narrow and meets the span of the corridor and there are relatively complete and hard bedrocks distributed on both sides of the bank slopes, the bedrocks on both sides of the gully are used as the foundation support of the corridor. When the longitudinal top beam is arranged on the top of the arched beam frame, the arched cross beam spans across both sides of the gully, and the arch top is in the shape of "rice" character, the diagonal brace beams are used to connect between the two arched cross beams, and after the diagonal brace beams and the arched cross beams meet, they are embedded in the bedrocks on both sides of the gully, and the bottom connecting beam is used to enclose the corridor into a whole structure; when the arch top is in the shape of "well" character, the longitudinal side beams are used to connect between the two arched cross beams, the arched cross beams are embedded in the bedrocks on both sides of the gully, and the bottom connecting beam is used to enclose the corridor into a whole structure. Second, when there are no complete bedrocks on both sides of the gully and it is loose broken accumulation gravel soil, diversion side walls can be built on both sides of the spillway chute. When the longitudinal top beam is longitudinally arranged on the top of the arched beam frame, the arched cross beam spans across both sides of the gully, and when the arch top is in the shape of "rice" character, the diagonal brace beams are used to connect between the two arched cross beams, and the intersection of the diagonal brace beams and the arched cross beams is integrally cast with the diversion side wall to form an integral structure; when the arch top is in the shape of "well" character, the longitudinal side beams are used to connect between the two arched cross beams, and the arched cross beam is integrally cast with the diversion side wall to form an integral structure.

6. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 1, characterized in that: The described discharge chute is paved at the bottom with high-performance wear-resistant concrete of C25 or above C25, and the bottom is made into a "V" shape. An ultra-high reverse slope section is provided at the bend to restrain the water flow; preventing it from scouring the diversion side wall or the weathered layer of the bedrock.

7. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 1, characterized in that: The described steel mesh is welded into a circular arch shape with HRB400 ф32 steel bars, fully paved on the top of the corridor close to the beam frame, and connected to the steel bars embedded in the beam frame for fixation. The two bottom sides are fixed to the steel bars embedded in the diversion side wall or the bottom connecting beam.

8. The water-rock separation structure for debris flow prevention in mountainous areas according to claim 1, characterized in that: The described steel mesh also includes two different plane layouts. When the beam frame is in a "rice" shape structure, the steel mesh is made into a diamond structure to match it; when the beam frame is in a "well" shape structure, the steel mesh is made into a rectangular structure to match it.

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