Channel transformation structure for loess plateau collapse slip flow disaster chain prevention and control and construction method

Abstract

The invention relates to the technical field of loess plateau hilly and gully region collapse and slip flow disaster chain improvement, in particular to a loess plateau collapse and slip flow disaster chain prevention and control channel reconstruction structure and a construction method, and the method comprises the steps: dividing a channel into a source region, an overlay region, a dam region and an erosion region according to the elevation and channel trend through a trained machine learning algorithm; the material source area is provided with an energy dissipation device with an oval upper half part and a trapezoid lower half part and matched steps; a diversion pile, a siltation channel, a diversion channel and a flood discharge channel are arranged in the superposition area, and a silt farmland and a drainage blind ditch are built in the siltation channel; the dam area comprises a flood drainage section, a siltation section and a drainage step, and excavation steps are arranged in the corresponding areas of the channel slope. The construction is carried out through engineering geological survey and data supplementation, then through algorithm partitioning, transformation of all areas is carried out in a targeted mode, and finally regular desilting maintenance is carried out. By means of the structure and the method, channel energy dissipation, siltation utilization and flood control are achieved, and the requirements for loess plateau collapse slip flow disaster chain channel treatment are met.

Description

Technical Field

[0001] This invention relates to the field of landslide disaster chain management technology in the hilly and gully areas of the Loess Plateau, specifically to a gully modification structure and construction method for preventing landslide disaster chains in the Loess Plateau. Background Technology

[0002] In the hilly and gully regions of the Loess Plateau, earthen dams, known as "silt-retaining dams," are frequently constructed in the gullies to prevent siltation and land accumulation. However, with the northward shift of the rain belt, extreme heavy rainfall frequently occurs in these areas. While these early silt-retaining dam projects have created new siltation areas and expanded arable land to some extent, the frequent occurrence of heavy rainfall has also led to these dams serving as energy storage and disaster amplification facilities. Over time, these dams may face the risk of collapse.

[0003] Currently, the gully modification structures in the hilly and gully areas of the Loess Plateau are mostly pure earthen gravity dams. These only consider the dam area under their jurisdiction and cannot be linked with upstream loose deposit areas or gully confluence areas. Furthermore, they are not suitable for other complex loess regions. While they often meet the requirement of "retaining silt and creating silt," they fail to meet the needs of water storage and disaster prevention, resulting in significant disaster risks and defects in gully modification projects, affecting the later use of farmland in silted-up areas. Summary of the Invention

[0004] In view of this, the present invention addresses the shortcomings of the prior art by proposing a gully modification structure and construction method for the hilly and gully areas of the Loess Plateau, aiming to solve at least one of the problems mentioned in the background art.

[0005] In a first aspect, the present invention provides a gully modification structure for the prevention and control of landslide disaster chains in the Loess Plateau, comprising: using a machine learning algorithm to divide the gully in the hilly and gully area of ​​the target Loess Plateau into a source area, a superposition area, a dam area and an erosion area, wherein the source area is provided with a gully energy dissipation device, and an energy dissipation device step is provided on one side of the energy dissipation device.

[0006] In some embodiments, the cross-sectional shape of the energy dissipation device is elliptical in the upper half and trapezoidal in the lower half.

[0007] In some embodiments, the superimposed area is provided with diversion piles, and a siltation channel is provided between the diversion piles and the ditch slope. A diversion channel is provided on one side of the siltation channel, and a flood discharge channel is connected to the side of the diversion channel away from the siltation channel. A drainage step is provided at the end of the flood discharge channel, and the drainage step is connected to a first flood discharge channel. A flood discharge section is provided on one side of the first flood discharge channel, and a siltation section is provided at the end of the siltation channel.

[0008] In some embodiments, the interior of the siltation channel is provided with silted farmland, and the interior of the silted farmland is provided with drainage blind ditches.

[0009] In some embodiments, the ditch slope is provided with excavation steps corresponding to the siltation section and the flood discharge section.

[0010] Secondly, this invention provides a method for constructing a channel modification structure for preventing landslide disaster chains in the Loess Plateau, comprising the following steps: Engineering geological surveys should be conducted in the land area to be transformed in the gully to ascertain the topography, geological structure and soil properties of the gully area, and to determine the design parameters and construction content; if necessary data is missing, it is necessary to supplement the data. The collected gully data were classified and placed into a test set. A trained classification machine learning algorithm was used to partition the area of ​​the gully to be modified, dividing the gully into the following areas along the elevation and direction: source area, superposition area, dam area and erosion area. Select appropriate renovation technologies and methods for the well-defined areas; Grass seed mortar was sprayed on the slope and deposits in the source area. Crushed stone was collected in the source area and filled into the energy dissipation device. Cement mortar was used to shape the surface of the energy dissipation device. Then, energy dissipation device steps were filled behind the energy dissipation device. In the designated dam area, flood discharge channels are excavated, and the excavated soil is piled into siltation channels through the constructed diversion channels to form siltation farmland. Diversion piles are constructed in the designated overlapping area, the length of the siltation channel is longer than the length of the flood discharge channel, and a diversion channel is reserved to extend to the location of the siltation dam; On the slope of the gully, the interface of the silt-retaining dam is excavated. While excavating, the steps are reinforced with a tamping hammer. After the excavation is completed, an ion-biological composite slurry layer is sprayed onto the interface. After waiting for calcium carbonate to precipitate on the surface of loess particles and form a 3-5cm thick reverse seepage layer, the flood discharge section and siltation section of the silt-retaining dam are filled in. A drainage channel for the silt-retaining dam is reserved in the middle. Drainage steps are built before and after the silt-retaining dam to complete the construction of the gully transformation structure in the hilly and gully area of ​​the Loess Plateau. The flood discharge channel is dredged at fixed times each year, and farmland is built on the silted-up area above the channel.

[0011] Compared with existing technologies, the advantages of this invention are as follows: By using machine learning algorithms to precisely partition the gully according to elevation and channel orientation, the modification measures for the source area, superposition area, dam area, and erosion area are more targeted, solving the problem of insufficient precision in traditional modification schemes. The energy dissipation device and matching steps with an elliptical + trapezoidal profile in the source area can efficiently dissipate water flow energy and reduce gully erosion. The coordinated design of superposition diversion piles, siltation channels, and flood discharge channels can both divert floodwater to prevent overflow and utilize silt to form silt-free farmland. Combined with drainage blind ditches, this effectively solves the problem of waterlogging in farmland, achieving a win-win situation for soil and water conservation and land resource utilization. The excavation of steps, the setting of an ion-biological composite slurry reverse osmosis layer, and drainage steps in the dam area significantly improves the stability and seepage resistance of the gully modification structure, reducing the risk of dam failure. Meanwhile, the scientific construction process and regular dredging and maintenance mechanism ensure the long-term effectiveness of the transformation, which can not only effectively prevent floods and reduce erosion, but also increase the area of ​​arable land and improve the regional ecological environment, providing reliable support for the ecological protection and sustainable agricultural development of the Loess Plateau hilly and gully area.

[0012] The above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure.

[0013] Other features and aspects of this disclosure will become clearer from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 A top view of the gully modification structure in the hilly and gully region of the Loess Plateau provided in an embodiment of the present invention; Figure 2 A cross-sectional view of the gully modification structure in the hilly and gully region of the Loess Plateau provided in an embodiment of the present invention; Figure 3 A cross-sectional view of the gully modification structure in the hilly and gully region of the Loess Plateau provided in an embodiment of the present invention; Figure 4 A top view of the gully modification structure in the hilly and gully region of the Loess Plateau provided in an embodiment of the present invention; Figure 5 A cross-sectional view of the gully modification structure in the hilly and gully region of the Loess Plateau provided in an embodiment of the present invention; Figure 6 A cross-sectional view of the gully modification structure in the hilly and gully region of the Loess Plateau provided in an embodiment of the present invention; Figure 7 A flowchart illustrating the construction method for gully channel modification in the hilly and gully region of the Loess Plateau, as provided in this embodiment of the invention.

[0016] Among them: 1. Source area; 11. Source area slope; 12. Source area deposits; 13. Energy dissipation device; 14. Energy dissipation device steps; 2. Overlapping area; 21. Ditch slope; 22. Silt-covered farmland; 23. Siltation channel; 24. Diversion pile; 25. Diversion channel; 26. Flood discharge channel; 27. Drainage blind ditch; 3. Dam area; 31. Flood discharge section; 32. Siltation section; 33. Drainage steps; 34. First flood discharge channel; 4. Erosion area; 41. Excavated steps. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0019] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] See Figure 1-7As shown, in the first embodiment, a gully modification structure for preventing landslide disaster chains in the Loess Plateau according to an embodiment of this application includes: Machine learning algorithms were used to divide the gullies in the hilly and gully region of the Loess Plateau into source area 1, superposition area 2, dam area 3, and erosion area 4.

[0022] In some specific embodiments, the material source area 1 is provided with a channel energy dissipation device 13, and an energy dissipation device step 14 is provided on one side of the energy dissipation device 13.

[0023] In some specific embodiments, the cross-sectional shape of the energy dissipation device 13 is elliptical in the upper half and trapezoidal in the lower half.

[0024] In some specific embodiments, the superimposed area 2 is provided with diversion piles 24, and a siltation channel 23 is provided between the diversion piles 24 and the ditch slope 21. A diversion channel 25 is provided on one side of the siltation channel 23. A flood discharge channel 26 is connected to the side of the diversion channel 25 away from the siltation channel 23. A drainage step 33 is provided at the end of the flood discharge channel 26. The drainage step 33 is connected to a first flood discharge channel 34. A flood discharge section 31 is provided on one side of the first flood discharge channel 34. A siltation section 32 is provided at the end of the siltation channel 23.

[0025] In some specific embodiments, the siltation channel 23 is provided with silted farmland 22 inside, and the silted farmland 22 is provided with drainage blind ditch 27 inside.

[0026] In some specific embodiments, the ditch slope 21 is provided with excavation steps 41 corresponding to the siltation section 32 and the flood discharge section 31.

[0027] The second embodiment, according to an embodiment of this application, includes a method for constructing a gully modification structure for preventing landslide disaster chains in the Loess Plateau, comprising the following steps: Engineering geological surveys should be conducted in the land area to be transformed in the gully to ascertain the topography, geological structure and soil properties of the gully area, and to determine the design parameters and construction content; if necessary data is missing, it is necessary to supplement the data. The collected gully data were classified and placed into a test set. The trained classification machine learning algorithm was used to partition the area of ​​the gully to be modified, and the gully was divided into the following areas along the elevation and direction: source area 1, superposition area 2, dam area 3 and erosion area 4. Select appropriate renovation technologies and methods for the well-defined areas; Grass seed mortar was sprayed on the slope 11 and the sediment accumulation 12 in the sediment source area. Crushed stone was collected in the sediment source area 1 and filled into the energy dissipation device 13. Cement mortar was used to shape the surface of the energy dissipation device 13. Then, the energy dissipation device steps 14 were filled behind the energy dissipation device 13. In the designated dam area 3, a flood discharge channel 26 is excavated, and the excavated soil is piled in the siltation channel 23 through the constructed diversion channel 25 to form siltation farmland 22. In the designated superimposed zone 2, diversion piles 24 are constructed, the length of siltation channel 23 is greater than the length of flood discharge channel 26, and a diversion channel 25 is reserved to extend to the location of the siltation dam. On the slope 21 of the gully, the interface of the silt-retaining dam is excavated. While excavating, the excavated steps are reinforced with a tamping hammer. After the excavation is completed, an ion-biological composite slurry layer is sprayed onto the interface. After waiting for calcium carbonate to precipitate on the surface of loess particles and form a 3-5cm thick reverse seepage layer, the flood discharge section 31 and the siltation section 32 of the silt-retaining dam are filled. A drainage channel for the silt-retaining dam is reserved in the middle. Drainage steps are built before and after the silt-retaining dam to complete the construction of the gully transformation structure in the hilly and gully area of ​​the Loess Plateau. The flood discharge channel is dredged at fixed times each year, and farmland is built on the silted-up area above the channel.

[0028] It should be understood that, firstly, machine learning algorithms are used to precisely divide the target area into four functional zones according to the elevation and direction of the gully: 1. Source area; 2. Overlapping area; 3. Dam area; and 4. Erosion area, clearly defining the core objectives of governance in each zone. In the source area, an energy dissipation device 13 with an upper ellipse and lower trapezoidal profile and energy dissipation steps 14 are installed. The upper half of the ellipse disperses the impact force of the water flow, while the lower half of the trapezoid enhances structural stability. Simultaneously, gravel is filled to improve the energy dissipation effect and weaken the scouring effect of the water flow on the slope 11 and deposits 12 of the source area. In the overlapping area, water flow is guided by diversion piles 24, diverting sediment-laden water into the siltation channel 23. After sediment deposition, silt-covered farmland 22 is formed, and drainage blind ditches 27 within the farmland drain excess water. Floodwater exceeding the siltation capacity is diverted through the diversion channel 25 into the flood discharge channel 26, and then connected to the first flood discharge channel 34 of the dam area via drainage steps 33, achieving flood and sediment diversion. The flood discharge section 31 in the dam area receives and discharges floodwaters, while the siltation section 32 stores sediment and continuously expands its capacity. The gully slope 21 is equipped with excavated steps 41 corresponding to the siltation section 32 and the flood discharge section 31, which reduces the slope gradient and enhances stability. The erosion zone is linked with other regional structures to reduce further erosion by water flow and form a complete prevention and control chain.

[0029] Machine learning algorithms enable precise functional zoning of regions, avoiding the traditional "one-size-fits-all" approach to governance. The structures of zones 1-4 are specifically designed to address energy dissipation and erosion prevention, silt diversion, flood control and sediment storage, and erosion prevention, significantly improving governance efficiency. In the superimposed zone, siltation channels 23 intercept sediment to form silt-covered farmland 22, increasing arable land resources. In the sediment source zone 1, grass seed mortar is sprayed to promote vegetation restoration, balancing soil and water conservation with agricultural production and ecological restoration. The "elliptical + trapezoidal" design of the energy dissipation device 13, diversion piles 24, and flood discharge channels 26 form a comprehensive flood control system. Drainage blind ditches 27 and reverse seepage layers solve waterlogging and leakage problems, adapting to the complex topography and hydrological conditions of the Loess Plateau. The structures of zones 1-4 form a closed loop of "source interception - intermediate diversion - end storage and discharge," gradually improving the topography of the gullies and achieving a virtuous cycle of the ecosystem.

[0030] In the early stages of construction, engineering geological surveys were conducted to determine the topography, geological structure, and soil properties of the valleys, and to identify design parameters and construction content. Data was promptly supplemented when needed to avoid construction deviations due to insufficient geological data. The collected valley data was categorized and incorporated into a test set. A trained machine learning algorithm was used to partition the modified gullies, ensuring that the division of the gully into four zones (1. Source Zone, 2. Overlapping Zone, 3. Dam Zone, and 4. Erosion Zone) closely matched the actual conditions. In Source Zone 1, grass seed mortar was first sprayed, followed by filling with crushed stone to form an energy dissipation device 13, and finally, energy dissipation device steps 14 were constructed. In Overlapping Zone 2 and Dam Zone 3, a flood discharge channel 26 was excavated simultaneously. Excavated soil was dumped through a diversion channel 25 to a siltation channel 23 to form silted farmland 22. Diversion piles 24 were constructed, and the slope junction was excavated and compacted. An ion-biological composite slurry was sprayed to form a 3-5cm reverse osmosis layer. Then, the flood discharge section 31 and siltation section 32 were constructed, with drainage channels reserved, and drainage steps 33 were built. After construction is completed, a long-term maintenance mechanism will be established, and the 26th flood discharge channel will be dredged at fixed times every year to ensure that all structures can function stably and in a long-term manner.

[0031] The preliminary survey was combined with machine learning-based zoning, and the construction plan was tailored to the actual geological and hydrological conditions. Dedicated construction processes were configured for zones 1-4 to avoid resource waste and structural failure caused by blind construction. Following the principle of "excavation and reinforcement simultaneously," the excavated steps 41 were promptly compacted, and an ion-biological composite slurry reverse osmosis layer was used to prevent dam leakage. The drainage system was constructed concurrently, ensuring the structure's impermeability and anti-sliding capabilities from the construction stage. The spraying of grass seed mortar in the source area 1 and the creation of silted farmland in the superimposed area 2 integrated engineering construction with ecological restoration and agricultural production, reducing environmental damage from construction. Post-construction dredging and maintenance, including timely removal of silt from the flood discharge channel 26, ensured that the corresponding structures in zones 1-4 would continue to provide comprehensive benefits in soil and water conservation, farmland expansion, and flood control.

[0032] Based on regional characteristics and classification, this invention uses machine learning algorithms to divide common gullies in the hilly and gully areas of the Loess Plateau into source areas, superposition areas, dam areas, and erosion areas along elevation and gully direction. Each area corresponds to a modification structure or technical solution designed for the hilly and gully areas of the Loess Plateau, and the technologies or structures used in each area will be linked accordingly.

[0033] Key characteristics of the source area: mainly high and steep slopes at the head of the gully, with thick deposits of landslides or collapses within the gully; the contents are mainly loess containing silt to fine sand, with a high water content.

[0034] Key features of the superimposed area: mainly the wide valley section in the middle and lower reaches of the channel, the confluence of multiple channels, and the superposition of multiple debris flows in history, forming a layered complex.

[0035] Key features of the dam area: mainly located at the mouth of a gully or at a relatively narrow point in a wide valley, controlled by an artificially constructed earth dam / barrier dam; the dam body is mostly constructed of local loose loess, with a few being concrete gravity dams; in front of the dam is silt deposited after multiple loess mudflows / mountain torrents, with a high water content; behind the dam are drainage channels and farmland for flood discharge and drainage.

[0036] Key characteristics of the erosion zone: mainly wide valleys or plains downstream of gullies, with the gully bed cut down to bedrock or thick alluvial layers, and the bed slope <5°, or loess slopes that are not prone to large landslides.

[0037] The source area involves a plant-based ecological protection technology and a gully leveling structure. By spraying grass seed mortar onto the slopes and deposits in the source area, slope consolidation is accelerated; the gully slope is reduced, thereby reducing the occurrence of landslides and debris flows at the source and fixing geological hazards in other areas into manageable flash floods. Small-flow flash floods, after passing through the gully energy dissipation device, have their energy dissipated and remain in the source area. Large-flow flash floods, after passing through the energy dissipation device, will have large particles of soil deposited on the steps of the energy dissipation device, and the mud-water mixture, after energy dissipation, enters the superposition zone.

[0038] The energy dissipation device used in the source area has an elliptical upper section and a trapezoidal lower section. It is a whole-gravel energy dissipation device formed by piling up local gravel, with a cement finish on the surface. Upstream of the energy dissipation device, there are energy dissipation steps to gradually eliminate the impact of small flash floods on the energy dissipation device and collect large mud and rocks left by large flash floods.

[0039] The superimposed area and dam area involve an improved siltation dam structure that diverts flash floods formed during rainfall through diversion piles. When the flash flood flow is small, the flash flood tends to flow into a narrow and deep spillway, thus forming an irrigation reservoir. When the flash flood flow is large, most of the flash flood flows into a wide and shallow siltation channel. After dissipation of potential and energy, most of the rainwater flows into the spillway through the diversion channel, forming siltation farmland after the flash flood.

[0040] The silt-retention dam is divided into a flood discharge section and a siltation section, connected by a flood discharge channel. The siltation channel is equipped with a blind ditch made entirely of crushed stone, which connects to the flood discharge channel to drain excess water from the silted farmland.

[0041] The erosion zone involves a technique for treating the interface between the silt-retaining dam and the fill slope. This involves excavating the original slope in multiple steps, compacting each step with a tamping hammer, and injecting an "ion-biological composite slurry" layer into the interface between the silt-retaining dam and the fill slope. This induces calcium carbonate precipitation on the surface of loess particles, forming a reverse seepage layer approximately 3-5 cm thick. The flood discharge section and siltation section of the silt-retaining dam are then constructed on the treated interface.

[0042] The modification method and construction process include the following steps: Step 1: Conduct an engineering geological survey of the land area to be transformed in the gully to ascertain the topography, geological structure and soil properties of the gully area, and determine the design parameters and construction content; if necessary data is missing, it is necessary to supplement the data.

[0043] In this embodiment, the necessary data for dividing the land area of ​​the ditch to be transformed into zones are: regional topographic map (1:5000~1:200), digital elevation model, geological data, hydrological data, and soil and rock data.

[0044] Step 2: Classify the collected gully data and put it into the test set. Use the trained classification machine learning algorithm to partition the area of ​​the gully to be modified, and divide the gully into the following areas along the elevation and direction: source area, superposition area, dam area and erosion area. Key features of the source area 1: It mainly consists of steep slopes at the head of the gully, with thick deposits of landslides or collapses within the gully; the contents are mainly loess containing silt to fine sand, with a high water content.

[0045] Key features of the superimposed zone 2: It mainly consists of the wide valley section in the middle and lower reaches of the channel, the confluence of multiple channels, and the superposition of multiple debris flows in history, forming a layered complex.

[0046] The three key characteristics of the dam area are: mainly the mouth of a gully or the relatively narrow part of a wide valley, the area controlled by artificially constructed earth dams / landslide dams; the dam body is mostly filled with local loose loess, and a few are concrete gravity dams; in front of the dam is silt formed after multiple loess mudflows / mountain floods, with a high water content; behind the dam are drainage channels and farmland for flood discharge and drainage.

[0047] The key characteristics of the erosion zone 4 are: it is mainly a wide valley or plain in the lower reaches of a gully, the gully bed cuts down to the bedrock or thick alluvial layer, the slope of the bed surface is <5°, or it is a loess slope that is not prone to large landslides.

[0048] Step 3: Select appropriate transformation technologies and methods for the identified areas. The source area involves a plant ecological protection technology and gully leveling structure. The superimposed area and dam area involve an improved siltation dam siltation structure. The erosion area involves a gully interface treatment technology. Source area 1 involves a plant ecological protection technology and gully leveling structure. By spraying grass seed mortar on the slope 11 and the sediment deposits 12 of the source area, the slope consolidation is accelerated; the gully slope is reduced, reducing the generation of landslides and debris flows from the source, and fixing geological hazards in other areas into easily manageable flash floods. Flash floods with small flow rates are dissipated after flowing through the gully energy dissipation device 13 and remain in source area 1. Flash floods with large flow rates are deposited on the energy dissipation device steps 14 after flowing through the energy dissipation device 13. The mud-water mixture is then dissipated and enters the superposition zone 2.

[0049] Step 4: Spray grass seed mortar on the slopes and deposits in the source area. Collect gravel in the source area and fill it into the energy dissipation device. Shape the surface of the energy dissipation device with cement mortar, and then build energy dissipation device steps behind it.

[0050] It should be noted that the channel energy dissipation device 13 used in source area 1 has an elliptical upper section and a trapezoidal lower section. This shape utilizes the composite cross-section of the upper elliptical streamline and the lower trapezoidal contraction section to change the local velocity distribution, causing sediment to be deposited at the leading edge of the device or discharged with the high-speed core area, thus achieving a balance between sediment reduction and scour in the channel. The device is formed by piling up local crushed stone, with a cement finish, making the material readily available. An energy dissipation step 15 is set upstream of the channel energy dissipation device 13. Flash floods ascend step by step through the step, consuming kinetic energy and eliminating the impact of small flash floods on the channel energy dissipation device 13. The characteristics of the energy dissipation device 13 determine that even if a large flash flood passes through, it can leave behind large mud and rocks.

[0051] Step 5: Excavate flood discharge channels in the designated dam area. The excavated soil is then piled into siltation channels through the constructed diversion channels, forming the earliest siltation farmland.

[0052] It should be noted that the flood discharge channel 26 is narrow and deep, while the siltation channel 23 is wide and shallow, with a difference of 3-5 meters in the bottom elevation of the channels. When the flash flood flow is small, the flash flood tends to flow into the narrow and deep flood discharge channel 26, thus forming an irrigation reservoir. When the flash flood flow is large, most of the flash flood flows into the wide and shallow siltation channel 23. After the potential energy is dissipated, most of the rainwater flows into the flood discharge channel 34 through the diversion channel 25, forming silted farmland 22 after the flash flood.

[0053] Step 6: Construct diversion piles in the designated overlapping area, with the siltation channel side being longer and the flood discharge channel side being shorter, reserving diversion channels that extend all the way to the siltation dam location.

[0054] It should be noted that the materials used for diversion piles 24 are generally reinforced concrete and ditch loess. Generally, only the front part that is in direct contact with water is made of reinforced concrete. The diversion piles that divide the siltation channel 23 and the flood discharge channel 26 can be filled with loess.

[0055] Preferably, all diversion piles 24 can be constructed using reinforced concrete.

[0056] Step 7: Excavate the interface of the silt-retaining dam on the slope of the gully. While excavating, use a tamping hammer to reinforce the excavated steps. After the excavation is completed, spray the "ion-biological composite slurry" layer onto the interface. Wait for the calcium carbonate on the surface of the loess particles to precipitate and form a reverse seepage layer of about 3-5 cm thick. Then, fill the flood discharge section and siltation section of the silt-retaining dam, leaving a drainage channel for the silt-retaining dam in the middle. Build drainage steps (33) in front of and behind the silt-retaining dam to complete the construction of the gully transformation structure in the hilly and gully area of ​​the Loess Plateau.

[0057] Preferably, when excavating the interface, a table of recommended excavation schemes for different slopes can be used as a reference.

[0058] Recommended Excavation Schemes for Slopes with Different Heights

[0059] Step 8: Dredge the flood discharge channel at fixed times each year and build farmland on the silted-up area above the channel.

[0060] The gully transformation structure and construction process described in this invention for the Loess Plateau hilly and gully region is simple to obtain materials and easy to implement. It rationally divides the common Loess Plateau hilly and gully region into four major areas: source area, superimposed area, dam area, and erosion area. This regional division method is applicable to most Loess hilly and gully areas and is easy to promote and implement. Each area corresponds to a transformation technology, which works in tandem and coordinates with each other to coordinate loess gully resources from a regional perspective, creating high-quality loess gully siltation farmland. The transformed loess gullies retain the "silt retention and siltation" function of existing siltation dams. Furthermore, due to the unique design of the flood discharge channels in the superimposed and dam areas, not only are irrigation reservoirs formed, but the formation of siltation is also accelerated. Faced with increasingly frequent extreme rainfall events, the new loess gully structure can effectively reduce the occurrence of mountain disasters such as landslides, flash floods, and debris flows, maintaining regional safety.

[0061] In this invention, the energy dissipation device in the ditch of the material source area adopts a streamlined elliptical top and a contracting trapezoidal bottom to form a transverse circulation of "high speed at the bottom and slow flow at the surface". Sediment larger than 0.05mm is automatically swept and thrown into the silt storage area in front of the dam, and clear water overflows the top and enters the downstream. A single flood can achieve a sediment separation rate of ≥75%, and the reservoir can be reduced by more than 30% in 5 years.

[0062] In this invention, a narrow and deep flood discharge channel and a wide and shallow siltation channel are superimposed in the superimposed zone and dam area. When the flow of mountain torrents is small after being diverted by diversion piles, the torrents tend to flow into the narrow and deep flood discharge channel, thus forming an irrigation reservoir. The flood discharge channel area serves as a reservoir for water storage in normal times and plays a role in flood discharge in the event of extreme rainfall.

[0063] In this invention, when treating the sediment deposits 12, ditch slopes 21, superimposed areas 2, and dam areas 3, the original ground surface is usually covered with a lot of vegetation and topsoil. The topsoil contains a lot of plant roots and cannot be used to fill the foundation of the silted farmland 22 and dam areas 3, otherwise it will become a weak layer in the foundation, and it will be difficult to predict the future stability of the farmland and the deformation of the dam. Therefore, the topsoil should be loosely spread onto the constructed silted farmland after the silted farmland has been treated.

[0064] In actual construction, the loess hilly and gully areas are covered with a large amount of loess, and the thickness of the loess cover varies. In this invention, it is necessary to modify a large area of ​​gully, so it is necessary to pay close attention to preventing foundation settlement and preventing water accumulation in farmland. However, in some areas where the loess layer is thin and the bedrock is shallow, it is also possible to excavate to the bedrock surface and then carry out anti-seepage treatment on the bedrock surface to serve as the base surface of the flood discharge channel, depending on the actual construction conditions.

[0065] This unique design for the loess hilly and gully region not only maximizes soil moisture retention of the silt-retaining dams but also prevents farmland water shortages due to pre-reserved drainage channels, facilitating crop cultivation and promoting agricultural development on the Loess Plateau. The novel and rational design is easy to promote and apply, enabling the modified loess gullies to simultaneously serve three functions: flood control and water storage, disaster prevention and mitigation, and sand retention and land reclamation. The adopted structure and processes are based on both industry and agriculture, promoting multidisciplinary integration. This effectively avoids chain reactions of disasters in the loess hilly and gully region while also creating suitable growing conditions for crops, facilitating diversified agricultural development in the Loess Plateau hilly and gully area and promoting ecological restoration and system evolution.

[0066] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A gully modification structure for preventing landslide disaster chains in the Loess Plateau, characterized in that, include: Machine learning algorithms were used to divide the gullies in the hilly and gully region of the Loess Plateau into source areas, superposition areas, dam areas and erosion areas. The source areas were equipped with gully energy dissipation devices, and energy dissipation device steps were provided on one side of the energy dissipation devices.

2. The gully modification structure for preventing landslide disaster chains in the Loess Plateau according to claim 1, characterized in that, The cross-sectional shape of the energy dissipation device is elliptical in the upper half and trapezoidal in the lower half.

3. The gully modification structure for preventing landslide disaster chains on the Loess Plateau according to claim 2, characterized in that, The superimposed area is equipped with diversion piles, and a siltation channel is set between the diversion piles and the ditch slope. A diversion channel is set on one side of the siltation channel, and a flood discharge channel is connected to the side of the diversion channel away from the siltation channel. A drainage step is set at the end of the flood discharge channel, and the drainage step is connected to a first flood discharge channel. A flood discharge section is set on one side of the first flood discharge channel, and a siltation section is set at the end of the siltation channel.

4. The gully modification structure for preventing landslide disaster chains in the Loess Plateau according to claim 3, characterized in that, The siltation channel contains silted farmland, and the silted farmland contains drainage blind ditches.

5. The gully modification structure for preventing landslide disaster chains on the Loess Plateau according to claim 4, characterized in that, The ditch slope is provided with excavation steps corresponding to the siltation section and the flood discharge section.

6. A method for constructing a gully modification structure for preventing landslide disaster chains in the Loess Plateau, characterized in that, The gully modification structure applied to the prevention and control of landslide disaster chains in the Loess Plateau as described in any one of claims 1 to 5 includes the following steps: Engineering geological surveys should be conducted in the land area to be transformed in the gully to ascertain the topography, geological structure and soil properties of the gully area, and to determine the design parameters and construction content; if necessary data is missing, it is necessary to supplement the data. The collected gully data were classified and placed into a test set. A trained classification machine learning algorithm was used to partition the area of ​​the gully to be modified, dividing the gully into the following areas along the elevation and direction: source area, superposition area, dam area and erosion area. Select appropriate renovation technologies and methods for the well-defined areas; Grass seed mortar was sprayed on the slope and deposits in the source area. Crushed stone was collected in the source area and filled into the energy dissipation device. Cement mortar was used to shape the surface of the energy dissipation device. Then, energy dissipation device steps were filled behind the energy dissipation device. In the designated dam area, flood discharge channels are excavated, and the excavated soil is piled into siltation channels through the constructed diversion channels to form siltation farmland. Diversion piles are constructed in the designated overlapping area, the length of the siltation channel is longer than the length of the flood discharge channel, and a diversion channel is reserved to extend to the location of the siltation dam; On the slope of the gully, the interface of the silt-retaining dam is excavated. While excavating, the steps are reinforced with a tamping hammer. After the excavation is completed, an ion-biological composite slurry layer is sprayed onto the interface. After waiting for calcium carbonate to precipitate on the surface of loess particles and form a 3-5cm thick reverse seepage layer, the flood discharge section and siltation section of the silt-retaining dam are filled in. A drainage channel for the silt-retaining dam is reserved in the middle. Drainage steps are built before and after the silt-retaining dam to complete the construction of the gully transformation structure in the hilly and gully area of ​​the Loess Plateau. The flood discharge channel is dredged at fixed times each year, and farmland is built on the silted-up area above the channel.

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