A collaborative system and method for soil and water conservation in the tower foundation area of ​​power transmission and transformation projects.

Abstract

This invention discloses a collaborative system and method for controlling soil erosion in the base area of ​​power transmission and transformation projects, relating to the field of soil and water conservation and ecological restoration technology. The system includes a micro-topographic runoff control unit, a soil improvement unit, and a vegetation restoration unit. The micro-topographic runoff control unit consists of intercepting ditches, drainage ditches, and micro-water collection and storage facilities, forming a three-dimensional runoff control system of "upper interception, middle storage, and lower drainage." The soil improvement unit is a waste-based composite soil improvement layer, its raw materials being composted sludge, crushed straw, crushed construction waste, topsoil from the base area, and a water-retaining agent in a volume ratio of 1:1:0.5:2.5, with 0.1% water-retaining agent added. The vegetation restoration unit consists of a grass-shrub composite plant community. This invention, through deep synergy of engineering, materials, and plants, effectively controls soil erosion in the base area, reducing the soil erosion modulus by more than 80% and achieving a vegetation coverage of 68%, making it suitable for areas with severe soil erosion, such as the Loess Plateau.

Description

Technical Field

[0001] The invention relates to the fields of soil and water conservation engineering and ecological restoration technology, specifically to a collaborative management system and method for soil and water loss in the tower foundation area of ​​power transmission and transformation projects, which is particularly applicable to the prevention and control of soil and water loss and rapid ecological restoration of the slopes of ultra-high voltage power transmission line tower foundations in the hilly and gully areas of the Loess Plateau. Background Technology

[0002] Power transmission and transformation projects, especially ultra-high voltage direct current (UHVDC) transmission projects, inevitably disturb the land surface and damage vegetation during construction, leading to point-to-line soil erosion. In the Loess Plateau region of northern Shaanxi, where soil erosion is most severe, the soil is predominantly loess, with a loose structure and poor erosion resistance, and rainfall is concentrated and heavy rains are frequent. Transmission lines in this region are mostly distributed along loess hills and gullies, and tower foundation construction creates numerous artificially excavated slopes and spoil heaps. Under rainfall conditions, these slopes are highly susceptible to erosion, landslides, and other unstable damage, causing not only severe soil erosion but also threatening the stability of the tower foundations and even triggering safety accidents such as tower collapse.

[0003] Currently, soil and water conservation in tower base areas often employs single engineering measures (such as constructing intercepting and drainage ditches) or single biological measures (such as sowing grass seeds). However, traditional intercepting and drainage projects lack precise calculations of the complex water catchment conditions in tower base areas, resulting in crude designs that are ineffective in intercepting and diverting slope runoff. Simultaneously, simple vegetation restoration measures are limited by unfavorable conditions such as poor soil and low water and fertilizer retention capacity in tower base areas, leading to low vegetation survival rates, slow growth, long restoration cycles, and unsatisfactory control effects. Existing technologies lack a comprehensive management method that synergistically optimizes water catchment control with soil improvement and vegetation restoration, making it difficult to address soil and water loss problems in tower base areas at their source. Therefore, there is an urgent need to develop a synergistic management method that deeply integrates localized intercepting and drainage micro-topographic control with rapid vegetation restoration technology based on soil improvement. This would achieve an organic unity of engineering, soil, and vegetation measures, effectively improving the stability and erosion resistance of tower base slopes and ensuring the safety of power grid construction and operation. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a collaborative system and method for soil and water conservation in the tower foundation area of ​​power transmission and transformation projects. It aims to solve the technical problems in existing technologies, such as the disconnect between engineering and biological measures, difficulties in vegetation restoration due to soil infertility, and the lack of a systematic collaborative governance solution.

[0005] In a first aspect, the present invention provides a collaborative system for controlling soil and water loss in the tower foundation area of ​​power transmission and transformation projects.

[0006] A collaborative water and soil erosion control system for the tower foundation area of ​​a power transmission and transformation project includes:

[0007] The micro-topography runoff control unit includes a water interception ditch laid on the upper slope side of the tower base, a drainage ditch laid on the slope surface, and a micro water collection and retention facility laid on the slope surface between the water interception ditch and the drainage ditch. The water interception ditch is laid along the contour line, and the drainage ditch is laid along the direction perpendicular to the contour line of the slope surface and connected to the water interception ditch. The micro water collection and retention facility includes fish scale pits, ecological bags, or vegetation pits.

[0008] The soil improvement unit is a waste-based composite soil improvement layer laid on the surface of the artificially excavated slope, spoil slope, and the construction disturbance area of ​​the intercepting ditch and drainage ditch in the tower base area. The raw materials of the waste-based composite soil improvement layer consist of composted sludge, crushed straw, crushed construction waste, topsoil stripped from the surface of the tower base area, and water-retaining agent.

[0009] The vegetation restoration unit consists of a grass-shrub complex plant community planted in the soil improvement unit.

[0010] By organically integrating micro-topographic runoff regulation units, waste-based composite soil improvement units, and vegetation restoration units, a systematic governance platform with complementary functions and synergistic effects is formed. Interception ditches and drainage ditches reduce the erosion of the slope by surface runoff at the source, while micro-water collection and retention facilities increase slope roughness and local retention capacity, creating stable site conditions for vegetation restoration. The waste-based composite soil improvement layer improves soil physical structure and fertility, providing a good substrate for plant growth. The well-developed plant root system further enhances the shear strength and erosion resistance of the soil, working together with engineering measures to consolidate slope stability, achieving a three-in-one synergistic governance of engineering, soil, and vegetation.

[0011] Furthermore, the micro-topography runoff control unit also includes a stilling basin, which is located at the end of the drainage ditch and connected to the natural ditch. The stilling basin is 1.5m long, 1.0m wide, and 0.8m deep, and the bottom of the basin is paved with 20cm thick stones.

[0012] The stilling basin effectively reduces the kinetic energy of the discharged runoff, prevents local erosion and damage at the drainage outlet caused by water flow, protects the stability of the natural channel, and achieves a safe connection between the interception and drainage system and the natural terrain.

[0013] Furthermore, in the waste-based composite soil improvement layer, the volume ratio of the composted sludge, crushed straw, crushed construction waste, and the topsoil stripped from the tower base area is 1:1:0.5:2.5, and the water-retaining agent is polyacrylamide, which is added at a rate of 0.1% of the total volume of the composted sludge, crushed straw, crushed construction waste, and topsoil stripped from the tower base area.

[0014] By combining a specific ratio of composted sludge to provide organic matter and nutrients, crushed straw to improve soil pore structure and aeration, crushed construction waste to regulate pH and form a supporting framework, and polyacrylamide water-retaining agent to enhance water retention, a composite soil amendment with complementary functions and optimized structure is formed, comprehensively improving the physical, chemical, and biological properties of the soil. This formulation, after systematic pot experiment screening, significantly outperformed other formulations in terms of plant germination rate, biomass, and soil organic matter content.

[0015] Furthermore, the thickness of the waste-based composite soil amendment layer is 10cm to 30cm.

[0016] The modified layer of a specific thickness ensures that the plant roots have enough room to grow and can provide sufficient water and fertilizer supply, while also taking into account the economic efficiency of the project.

[0017] Furthermore, the intercepting ditch has a trapezoidal cross-section with a bottom width of 0.4m, a depth of 0.5m, a side slope ratio of 1:0.5, and a longitudinal slope of 0.5% to 1.0% at the bottom. It is constructed using M7.5 mortar-grouted rubble masonry, and a 10cm thick gravel cushion layer is laid at the bottom of the ditch.

[0018] The trapezoidal cross-section has good hydraulic performance and structural stability. The masonry rubble and gravel cushion layer enhance the scour resistance and drainage efficiency, meeting the flow requirements of the design runoff peak flow.

[0019] Furthermore, the drainage ditch is a precast concrete U-shaped channel structure with a width of 0.4m, a depth of 0.35m, a wall thickness of 6cm, and a length of 0.5m for each section. The sections are connected by a socket joint, and the joints are filled with M10 mortar.

[0020] The U-shaped channel structure has good integrity and resistance to deformation. The socket connection is easy to construct and has good sealing performance. The quality of prefabricated components is controllable and the construction efficiency is high.

[0021] Furthermore, the fish-scale pits are arranged in a triangular pattern along the contour lines, with an opening width of 0.5m and a depth of 0.3m; the planting holes have a diameter of 0.2m and a depth of 0.2m.

[0022] The triangular arrangement of the fish-scale pits can intercept slope runoff to the greatest extent and increase rainwater infiltration; the planting pits provide a local water collection environment for shrub planting and improve the survival rate.

[0023] Furthermore, the herbaceous plants in the vegetation restoration unit include awnless brome, alfalfa, and crested wheatgrass, while the shrubs include Caragana korshinskii and sea buckthorn.

[0024] The selected native plant species are all drought-resistant, tolerant of poor soil, and have well-developed root systems. Herbaceous plants quickly form surface cover to reduce soil erosion, while shrubs have deep roots to stabilize the soil and enhance the long-term stability of the slope, thus forming a multi-layered and multifunctional composite vegetation community.

[0025] Secondly, the present invention provides a method for the coordinated management of soil and water loss in the tower foundation area of ​​power transmission and transformation projects to implement the above-mentioned system.

[0026] A method for collaborative management of soil and water loss in the tower foundation area of ​​power transmission and transformation projects to implement the system described in any of the preceding claims.

[0027] Collect topographic and meteorological data of the base area, use the inference formula method to calculate the design peak runoff, and determine the layout of the interception and drainage system;

[0028] According to the layout, intercepting ditches are laid along the contour lines, and drainage ditches are laid along the direction perpendicular to the contour lines of the slope to connect with the intercepting ditches. Fish scale pits, ecological bags or vegetation pits are laid on the slope between the intercepting ditches and the drainage ditches as micro water collection and retention facilities.

[0029] The composted sludge, crushed straw, crushed construction waste, topsoil stripped from the tower base area, and water-retaining agent are mixed in a volume ratio of 1:1:0.5:2.5, and 0.1% polyacrylamide water-retaining agent is added. After being mechanically stirred and mixed evenly, the mixture is laid on the slope and tilled into the topsoil to form a waste-based composite soil improvement layer.

[0030] Herbaceous plants and shrubs are sown on the waste-based composite soil improvement layer to form a grass-shrub composite plant community.

[0031] This governance method boasts a high degree of standardization, achieving a closed-loop technology process encompassing catchment calculation, engineering layout, soil improvement, and vegetation restoration. Precise runoff calculations determine the parameters of the interception and drainage system, avoiding the extensive nature of traditional designs. The preparation and application of waste-based improvement layers enable the on-site resource utilization of engineering waste. A combination of grass and shrub vegetation creates a stable ecological community. This method can be customized for different pole types and slopes, demonstrating strong applicability and widespread application value.

[0032] Furthermore, the reasoning formula method uses a design rainfall intensity of 45 mm / h and a runoff coefficient of 0.55; the herbaceous plants are sown by broadcasting, with a sowing rate of 80 kg / hm² for awnless bromegrass, 30 kg / hm² for alfalfa, and 45 kg / hm² for crested wheatgrass; the shrubs are sown by hole sowing, with a sowing depth of 2 cm to 3 cm, 5 to 8 seeds sown per hole, and a plant spacing of 1.0 m × 1.5 m.

[0033] The specific design and sowing parameters have been verified through field tests to ensure that the drainage system has sufficient flow capacity under rainfall conditions in the Loess Plateau region, while ensuring rapid seed germination and healthy seedling growth to form a stable vegetation community.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The deep integration of engineering and biological measures: interception and drainage facilities enable the orderly diversion of runoff and provide water support for vegetation through localized interception; the soil stabilization of vegetation roots and surface cover enhance the slope's resistance to erosion, thus contributing to the stability of the engineering project. The two work synergistically to improve the effectiveness of soil and water conservation. Experimental data show that the soil erosion modulus of the synergistic treatment group was reduced by 80.6% compared to the bare control, by 64.1% compared to single engineering measures, by 58.2% compared to single vegetation restoration, and by 75.8% compared to single soil improvement.

[0036] Targeted Soil Improvement: This invention utilizes a combination of waste compost fermentation products and inorganic amendments to improve the physical, mechanical, and biochemical properties of loess. After improvement, soil bulk density decreased by 12.6%, organic matter content increased by 91.5%, total nitrogen increased by 85.5%, total phosphorus increased by 91.7%, saturated water content increased by 40.7%, field water holding capacity increased by 41.9%, soil cohesion increased by 57.0%, internal friction angle increased by 23.9%, water-stable aggregate content increased by 67.6%, and disintegration rate decreased by 62.4%. This effectively solves the problems of slow growth and low survival rate caused by poor soil structure in traditional vegetation restoration.

[0037] Waste resource utilization: This invention transforms sewage sludge from sewage treatment plants, agricultural and forestry waste (straw, branches), and crushed construction waste into soil amendment components, achieving efficient utilization of engineering waste, reducing transportation costs and environmental impact; the cost of the amendment materials is controllable, suitable for large-scale promotion along the route, and is both economical and environmentally friendly.

[0038] Systematic governance solution: This invention forms a complete technical chain from water catchment analysis, engineering layout, soil improvement, vegetation restoration to effect monitoring, and constructs an integrated governance system of engineering, soil and vegetation. It is fully adaptable to the complex conditions of areas with severe soil erosion such as the Loess Plateau, and can be customized for different tower types and slopes, with strong applicability and promotion value. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating the method for coordinated management of soil and water loss in the tower foundation area of ​​power transmission and transformation projects according to the present invention. Detailed Implementation

[0040] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. The described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a collaborative system and method for controlling soil erosion in the tower foundation area of ​​a power transmission and transformation project. It is applied to a typical tower foundation area along an ±800kV ultra-high voltage direct current transmission project in the Loess Plateau region of northern Shaanxi. This tower foundation area is located in a loess hilly and gully region with fragmented terrain, an average slope of 25°±3°, and loess soil of loose structure with poor erosion resistance. The average annual rainfall is approximately 500mm, concentrated in summer, resulting in severe soil erosion and significant gully and shallow erosion.

[0043] I. Water catchment characteristics analysis and micro-topography interception and drainage system design

[0044] 1.1 Catchment Calculation and Risk Assessment

[0045] Before construction began in the tower foundation area, a detailed site survey and data collection were conducted. Specifically, data on the type of transmission tower corresponding to the tower foundation (in this example, a ±800kV UHVDC transmission tower), tower height, tower root opening, and high-precision topographic data of the tower foundation area (using a 1:500 scale topographic map) were collected. Simultaneously, data on the average annual rainfall (approximately 500mm) and rainfall intensity for the area were collected from the local meteorological department.

[0046] Based on the tower type, height, and root spread data, combined with topographic data, the catchment area of ​​the tower and its base area was calculated. Specifically, using the hydrological analysis module of ArcGIS software, the catchment area on the upslope side of the tower base was extracted based on high-precision digital elevation model data, and the calculated catchment area was determined to be 0.032 km².

[0047] Based on the calculated catchment area and local rainfall intensity data, the peak runoff flow rate under a 20-year return period 1-hour rainfall intensity was calculated using the inference formula method. The design rainfall intensity was taken as i = 45 mm / h, and the runoff coefficient was taken as ψ = 0.55 based on the slope soil type and vegetation cover. Substituting these values ​​into the inference formula Q = 0.278 × ψ × i × F, the calculation was performed, where Q is the design peak runoff flow rate (m³ / s) and F is the catchment area (km²). The calculated design peak runoff flow rate is Q = 0.278 × 0.55 × 45 × 0.032 = 0.22 m³ / s.

[0048] Based on the calculation results, the characteristics of soil and water loss and the risk level of slope failure in the tower base area were assessed. The calculation results show that under the design rainfall conditions of a 20-year return period, the peak runoff flow on the upper slope of the tower base will be 0.22 m³ / s. If effective interception and drainage measures are not taken, severe gully and shallow erosion will occur on the slope, and the slope will have a high risk of landslide.

[0049] 1.2 Drainage System Layout

[0050] Based on the above water catchment characteristic analysis results, the layout of the micro-topography interception and drainage system is carried out using high-precision topographic data of the tower base area.

[0051] Interception ditches are laid along contour lines 1 to 2 meters from the outer edge of the top of the slope on both sides of the tower base. The ditches have a trapezoidal cross-section design, with a bottom width of 0.4 m, a depth of 0.5 m, a slope ratio of 1:0.5, a cross-sectional area of ​​0.45 m², and a longitudinal slope of 0.5% to 1.0%. Hydraulic testing confirms that their flow capacity meets the design flow requirement of 0.22 m³ / s. The ditches are constructed using M7.5 mortar-grouted rubble masonry, with a 10 cm thick gravel cushion layer at the bottom to enhance erosion resistance and drainage efficiency.

[0052] On the slope surface of the backfill area of ​​the tower base, longitudinal drainage ditches are laid out along a direction perpendicular to the contour lines of the slope. The spacing of the drainage ditches is 15m to 20m, and they are connected to the intercepting ditch. The drainage ditches adopt a precast concrete U-shaped channel structure, with dimensions of 0.4m width, 0.35m depth, and 6cm wall thickness, and each section is 0.5m long. The sections are connected by a socket joint, and the joints are filled with M10 mortar to ensure the integrity and sealing of the drainage ditches.

[0053] Taking into account the micro-topographical features of the slope, micro-water collection and retention facilities such as fish-scale pits, ecological bags, and planting pits were installed on the slope between intercepting ditches and drainage ditches, as well as at other suitable locations on the slope. The main function of these micro-water collection and retention facilities is to intercept a portion of the slope runoff, increase slope roughness to reduce runoff velocity, and provide localized water storage conditions for subsequent vegetation restoration. The fish-scale pits are arranged in a triangular pattern along contour lines, with each pit having an opening width of approximately 0.5m and a depth of approximately 0.3m. The ecological bags are made of biodegradable plant fiber materials and filled with a nutrient substrate containing plant seeds. The planting pits are small planting holes directly excavated on the slope, with a diameter of approximately 0.2m and a depth of approximately 0.2m.

[0054] The aforementioned intercepting ditches, drainage ditches, and micro-collection and storage facilities together constitute a three-dimensional runoff control system of "upper interception, middle storage, and lower drainage": intercepting ditches intercept water coming from uphill, drainage ditches orderly guide slope runoff, and micro-collection and storage facilities locally impound runoff, thereby minimizing the direct scouring of the slope by runoff.

[0055] A stilling basin is installed at the end of the drainage ditch where it connects to the natural channel. The stilling basin is 1.5m long, 1.0m wide, and 0.8m deep. The bottom is paved with 20cm thick stones, and the walls are constructed of mortar-grouted rubble masonry. The stilling basin effectively reduces the kinetic energy of the runoff discharged from the drainage ditch, prevents localized erosion and damage at the drainage outlet due to water flow, and ensures a safe connection between the drainage system and the natural terrain.

[0056] II. Preparation and Laying of Waste-Based Composite Soil Improvement Layer

[0057] 2.1 Raw material screening and pretreatment of composite soil amendment materials

[0058] The recyclable waste used in this embodiment is all collected from along and around the power transmission and transformation project, in order to achieve on-site resource utilization of waste. It mainly includes the following three categories:

[0059] The first category is wastewater treatment plant sludge, taken from dewatered sludge collected from urban wastewater treatment plants along power transmission and transformation projects that have passed relevant environmental protection testing standards. The initial moisture content is 75% to 80%. This dewatered sludge undergoes aerobic composting for 30 days, with the pile turned over every 5 days during the composting process, for a total of 5 times. After composting, the sludge's moisture content is reduced to below 45%, its organic matter content reaches above 28%, its total nitrogen content reaches above 1.8%, and its total phosphorus content reaches above 1.2%. The heavy metal content in the composted sludge should meet the standards of "Urban Wastewater Treatment Plant Sludge Disposal for Agricultural Use" and "Agricultural Sludge Pollutant Control Standard" to ensure the ecological safety of subsequent applications. This composted sludge is hereinafter referred to as composted sludge.

[0060] The second category is agricultural and forestry waste, which is taken from farmland and forest tending along the power transmission and transformation project. Specifically, it includes wheat straw, corn straw, and poplar branches. The straw is crushed to a length of 1cm to 3cm, and the poplar branches are crushed to particles of 0.5cm to 2cm. They are then mixed evenly and set aside for use.

[0061] The third category is shredded construction waste, collected from discarded bricks, tiles, and concrete blocks generated during the demolition of buildings along power transmission and transformation projects. This waste is crushed by a crusher and then screened to produce particles with a diameter of 2mm to 10mm. The main components of these particles are silicates and carbonates, which are used to improve the soil's pore structure and adjust its pH.

[0062] 2.2 Determination of the proportion of composite modified materials

[0063] To determine the optimal ratio of the composite improvement material, a systematic pot experiment was first conducted indoors before the field application of this embodiment, in order to screen out the ratio scheme that can maximize the promotion of plant growth and improve the physical and chemical properties of the soil.

[0064] Nine different volume ratio treatments (M1 to M9) were set up for the pot experiment, with unmodified local loess soil as the control (CK). The ratios of each treatment are detailed in Table 1. Each treatment was replicated three times, for a total of 30 pot experiment units. The pots were 30 cm in diameter and 35 cm in height plastic pots, each containing 15 kg of soil. The modified materials mixed according to different ratios were placed in the pots, and 20 alfalfa seeds were sown. The plants were cultured in an artificial climate chamber for 60 days under the following conditions: temperature 25 ± 2℃, light 12 hours / day, and humidity 60% ± 5%. After the culture period, the germination rate, aboveground biomass, root biomass, and soil organic matter content of each treatment were measured.

[0065] Table 1. Experimental Design for Screening Composite Modified Material Formulations

[0066]

[0067] Note: The water-retaining agent is polyacrylamide.

[0068] The experimental results are shown in Table 2. As can be seen from the data in Table 2, with the increase of the proportion of waste added, plant growth indicators and soil organic matter content generally showed a trend of first increasing and then stabilizing. Compared with the control group (CK), all treatments with added waste and water-retaining agent (M1 to M9) showed significant improvements in germination rate, biomass, and soil organic matter content. Among them, treatments M5, M6, and M7 showed the most outstanding performance, with germination rate and biomass significantly higher than other treatments (p<0.05), but the differences among the three treatments did not reach a statistically significant level.

[0069] Table 2. Effects of different ratios of composite amendments on plant growth

[0070]

[0071] Note: Data in the table are mean ± standard deviation; different lowercase letters in the same column indicate significant differences (p<0.05).

[0072] Taking into account the stability of waste sources, engineering application costs, and improvement effects, this embodiment preferably uses the M5 ratio as the final formulation for on-site application. Specifically, composted sludge, crushed straw, crushed construction waste, and topsoil from the tower base area are mixed in a volume ratio of 1:1:0.5:2.5, and 0.1% of polyacrylamide water-retaining agent is added to the total volume of the aforementioned raw materials. This ratio ensures good improvement effects while also considering the economy and availability of materials.

[0073] 2.3 On-site preparation and laying of composite modified materials

[0074] According to the above-mentioned optimized ratio, the composite modified material was prepared on a large scale at the construction site. First, the composted sludge, crushed straw, crushed construction waste, topsoil from the tower base area, and polyacrylamide water-retaining agent were accurately measured according to the ratio. Then, a forced mixer was used for mechanical mixing for no less than 3 minutes to ensure that all components were fully and evenly mixed, and that the polyacrylamide water-retaining agent was evenly distributed in the material.

[0075] In the artificially excavated slope surface, spoil slope surface, and areas disturbed by the construction of intercepting and drainage ditches in the tower base area, the prepared composite soil amendment material was evenly spread on the surface. Then, a rotary tiller was used to till the spread amendment material into the top 0cm to 30cm depth of the slope soil, tilling twice with the tilling directions perpendicular to each other to ensure thorough mixing of the amendment material with the original foundation soil. After leveling the slope, light compaction was used to smooth the surface, forming a 10cm to 30cm thick waste-based composite soil amendment layer. This amendment layer provides a matrix layer rich in organic matter, nutrient-rich, well-structured, and with a certain water retention capacity for subsequent vegetation restoration.

[0076] The changes in soil physicochemical properties before and after improvement are shown in Table 3. Six months after improvement, the test results showed that the soil bulk density decreased significantly by 12.6% (p<0.05) compared to before improvement, indicating a significant increase in the looseness of the improved layer, which is beneficial for plant root penetration and growth. Soil organic matter content increased by 91.5%, total nitrogen content increased by 85.5%, and total phosphorus content increased by 91.7%, indicating a fundamental improvement in the fertility level of the improved layer. Saturated water content and field capacity increased by 40.7% and 41.9%, respectively, indicating a significant enhancement in the water-holding capacity and water regulation capacity of the improved layer, providing a more stable water supply for plant growth.

[0077] Table 3 Comparison of main physicochemical properties of soil before and after improvement

[0078]

[0079] Note: Data in the table are mean ± standard deviation; different lowercase letters in the same row indicate significant differences (p<0.05).

[0080] III. Construction of Vegetation Restoration System

[0081] 3.1 Selection and configuration of suitable plants

[0082] Considering the climate and soil characteristics of the Loess Plateau in northern Shaanxi, and taking into account the local site conditions in the Tarim Basin, native plant species that are drought-resistant, tolerant of poor soil, have well-developed root systems, and strong soil-fixing capabilities were selected. The specific plant species selected in this embodiment and their characteristics are as follows:

[0083] Herbaceous plants include: Bromus inermis, a perennial grass that is drought-resistant, cold-resistant, and has a well-developed root system; Medicago sativa, a perennial leguminous plant with strong nitrogen-fixing ability and drought resistance; and Elymus dahuricus, a perennial grass that is drought-resistant, tolerant of poor soil, and has excellent water and soil conservation performance.

[0084] Shrubs include: Caragana korshinskii, a perennial leguminous shrub with a root system that can reach a depth of more than 5m. It is drought-resistant, cold-resistant, and tolerant of poor soil, making it an excellent shrub for soil and water conservation on the Loess Plateau; and Hippophaerhamnoides, a deciduous shrub that is drought-resistant, salt-tolerant, has a well-developed root system, and strong soil-fixing ability.

[0085] A multi-layered vegetation community structure is formed by adopting a configuration model of "combining grass and shrubs and complementing each other's advantages". Herbaceous plants form a rapid cover layer on the upper part of the slope, while grass and shrubs are mixed in the middle and lower parts of the slope to form a stable soil-fixing layer. Shrubs are planted in key areas of micro water collection and retention facilities (such as fish scale pits and planting holes).

[0086] 3.2 Co-planting

[0087] Sowing should be done in mid-June, before the local rainy season, to fully utilize subsequent natural rainfall to provide moisture for seed germination and seedling growth. Specific sowing parameters are as follows:

[0088] For the three herbaceous plants—awnless bromegrass, alfalfa, and crested wheatgrass—broadcasting was used. The sowing rate for awnless bromegrass was 80 kg / hm², for alfalfa 30 kg / hm², and for crested wheatgrass 45 kg / hm². During broadcasting, the three grass seeds were thoroughly mixed in the correct proportions and then evenly spread on the slope by hand or machine to ensure uniform seed distribution.

[0089] For both Caragana korshinskii and Hippophae rhamnoides shrubs, hill sowing was used. The parameters for hill sowing were: a sowing depth of 2-3 cm, 5-8 seeds per hill, and a plant spacing of 1.0 m × 1.5 m. During hill sowing, planting holes were dug on a waste-based composite soil amendment layer according to the predetermined plant spacing. After sowing the seeds in the holes, the soil was covered and compacted to ensure close contact between the seeds and the soil.

[0090] After sowing, cover the slope with non-woven fabric (15g / m²) to retain moisture. Secure the four corners of the fabric with soil to prevent it from being blown away by the wind. Covering with non-woven fabric effectively reduces soil moisture evaporation, creating a moist microenvironment for seed germination and seedling growth.

[0091] 3.3 Maintenance and Management

[0092] During the maintenance period, the following maintenance measures shall be taken:

[0093] Irrigation Management: Water every 3 to 5 days, depending on soil moisture, to keep the topsoil moist. The amount of water should be enough to thoroughly wet the top 15cm to 20cm of soil, avoiding overwatering which can cause surface runoff and nutrient loss. During the rainy season, reduce or suspend watering based on actual rainfall.

[0094] Weed removal: Manual weed removal is carried out once a month. The removed weeds are then used to cover the slope as natural organic matter to return to the field.

[0095] Reseeding: On the 30th day after sowing, conduct a seedling survey and promptly reseed or replant in areas with missing seedlings or broken rows to ensure uniform vegetation coverage.

[0096] Pest and disease control: Conduct regular inspections and take timely agricultural and biological control measures when pests and diseases are found. Strictly control the use of chemical pesticides to maintain ecological and environmental safety.

[0097] The maintenance period lasts for 90 days. After the vegetation community is initially established and the ground cover meets the design requirements, human intervention will be gradually reduced to allow the vegetation community to transition to a natural succession state.

[0098] 3.4 Vegetation growth effect

[0099] Six months after vegetation restoration, vegetation growth indicators of the collaborative treatment group (using the complete method of this embodiment) were investigated, and compared with the control group (T2) which only used vegetation restoration without interception and drainage projects and soil improvement. The survey results are shown in Table 4.

[0100] Table 4 Comparison of growth indicators of different treatments after 6 months of vegetation restoration

[0101]

[0102] Note: Data in the table are mean ± standard deviation; different lowercase letters in the same column indicate significant differences (p<0.05); T2 is the vegetation restoration only group, and T4 is the synergistic treatment group.

[0103] Table 4 clearly shows that the survival rate, average plant height, coverage, and aboveground biomass of all plants in the synergistic treatment group (T4) were significantly higher than those in the vegetation restoration group (T2) (p<0.05). Specifically, the average survival rate of herbaceous plants in the synergistic treatment group reached 86.7%, the average survival rate of shrubs reached 91.3%, and the total vegetation coverage of the slope reached 68.3%±2.5%, significantly higher than the 34.5%±2.1% in the vegetation restoration group (p<0.01). These results fully demonstrate that the waste-based composite soil amendment layer can provide sufficient water and fertilizer supply and a good growth substrate for vegetation restoration, thereby significantly improving the restoration effect and restoration speed.

[0104] IV. Verification of the effectiveness of soil and water conservation

[0105] 4.1 Experimental Design

[0106] To systematically verify the overall treatment effect of this invention, this embodiment set up 5 different treatment groups in the base area, using a completely randomized block design. Each treatment had 3 replicate plots, for a total of 15 test plots, each with an area of ​​20m × 5m. A 1m wide isolation zone was set between the plots to prevent the exchange of water and sediment between different treatments. A collection trough (5m wide, 0.3m high) and a runoff bucket (0.5m³ volume) were set at the lower boundary of each plot to collect and measure runoff and sediment generated by rainfall. The setup of each treatment is as follows:

[0107] Compared to CK: The exposed slope surface after the tower foundation construction disturbance was not treated with any remedial measures.

[0108] Treatment T1: Only intercepting and drainage ditches are laid, without soil improvement or vegetation restoration.

[0109] Treatment T2: Only vegetation restoration (same as the vegetation configuration of the collaborative treatment group) is carried out, without the installation of drainage projects or soil improvement.

[0110] Treatment T3: Only composite soil improvement is carried out (using the same mix ratio and laying method as the synergistic treatment group), without the installation of drainage works or vegetation restoration. Treatment T4: The complete synergistic treatment method of this embodiment is adopted, namely, drainage works + composite soil improvement + vegetation restoration.

[0111] 4.2 Runoff and Sediment Monitoring

[0112] Throughout the rainy season monitoring period, after each effective rainfall runoff event, the water depth in each runoff container was measured to calculate the total runoff volume, and water samples were collected to determine the sediment content. The total runoff volume and sediment content data were used to calculate the runoff coefficient and soil erosion modulus. The monitoring results for 12 months are shown in Table 5.

[0113] The results showed that the runoff coefficient of the control (CK) was as high as 0.32, and the soil erosion modulus was as high as 5780 t·km⁻²·a⁻¹, indicating a "severe" erosion intensity level. Treatment T1, which only implemented interception and drainage works, reduced the runoff coefficient to 0.18 and the soil erosion modulus to 3120 t·km⁻²·a⁻¹, a reduction of 46.0% compared to CK. However, due to the lack of vegetation cover on the slope, the erosion intensity was still classified as "moderate." Treatment T2, which only implemented vegetation restoration, achieved a vegetation cover of 34.5%. However, due to the lack of interception and drainage works to regulate runoff, the runoff coefficient remained at a relatively high level of 0.27, and the soil erosion modulus was 2680 t·km⁻²·a⁻¹. Treatment T3, which only underwent soil improvement, had a runoff coefficient as high as 0.30 and a soil erosion modulus of 4620 t·km⁻²·a⁻¹ due to the lack of interception and drainage projects and vegetation cover. The reduction was only 20.1%, which was not ideal.

[0114] Treatment T4, employing the complete synergistic management method of this embodiment, showed a runoff coefficient reduced to 0.11, a 65.6% decrease compared to the control (CK); the soil erosion modulus decreased to 1120 t·km⁻²·a⁻¹, an 80.6% decrease compared to the CK, achieving a "mild" erosion intensity level. All indicators were significantly better than other treatments (p<0.01). This result fully demonstrates that the synergistic management method of this invention can maximally control soil erosion, with effects far superior to single engineering or biological measures.

[0115] 4.3 Soil erosion resistance index test

[0116] Twelve months later, undisturbed soil samples were collected from each experimental plot at depths ranging from 0 cm to 20 cm using a five-point sampling method, with three replicates at each point, for a total of 15 samples. Soil bulk density was determined using the ring sampler method, the content of water-stable aggregates larger than 0.25 mm was determined using the wet sieving method, soil shear strength (cohesion c and internal friction angle φ) was determined using a direct shear test, and soil disintegration rate was determined using a disintegration tester. The test results are shown in Table 5.

[0117] Table 5 Comparison of soil erosion and soil erosion resistance indices under different treatments

[0118]

[0119] Note: Data in the table are mean ± standard deviation; different lowercase letters in the same column indicate significant differences (p<0.05).

[0120] The data in Table 5 show that treatment T4, which adopted the complete synergistic treatment method of this embodiment, had significantly better soil erosion resistance indicators than other treatments (p<0.01). Specifically: the soil cohesion c value of treatment T4 reached 13.5 kPa, which was 57.0% higher than CK and 25.0% higher than T2, which only underwent vegetation restoration; the internal friction angle φ reached 26.4°, which was 23.9% higher than CK; the content of water-stable aggregates larger than 0.25 mm reached 54.3%, which was 67.6% higher than CK; and the disintegration rate decreased to 3.2 cm³ / min, which was 62.4% lower than CK.

[0121] These data demonstrate that the synergistic treatment method of this invention significantly enhances the structural stability and erosion resistance of the soil. The organic matter and cementing substances in the waste-based composite soil amendment layer promote the formation of water-stable aggregates, while the well-developed vegetation root system further enhances the shear strength of the soil, thereby fundamentally improving the overall stability of the slope.

[0122] 4.4 Monitoring of Slope Micro-topography Changes

[0123] This embodiment also utilizes an all-solid-state 3D laser scanning sensor (Flash LiDAR) to periodically scan the slope micro-topography, with a scanning frequency of once every 3 months and a scanning accuracy of ±2mm. The acquired point cloud data, after denoising and registration, generates a high-precision digital elevation model (DEM, 5cm grid resolution). The DEM of Difference method is used to calculate the changes in slope erosion and deposition volume.

[0124] The 12-month monitoring results showed that no obvious gullies or landslides occurred on the T4 treated slope, and the slope morphology maintained good stability. The net erosion volume of the T4 treated slope was only 12.5% ​​of the control (CK), and slight deposition was also observed in some local areas of the slope, indicating that the slope is gradually entering a positive succession stage. This result is highly consistent with the soil and water loss data monitored by runoff plots, further verifying the synergistic treatment effect of the present invention.

[0125] V. Comprehensive Evaluation of Governance Effectiveness

[0126] The following significant results have been achieved through the collaborative application of this embodiment:

[0127] (1) Soil and water loss control: The soil erosion modulus decreased from 5780t·km⁻²·a⁻¹ before treatment to 1120t·km⁻²·a⁻¹, a reduction of 80.6%, the erosion intensity decreased from “strong” to “slight”, and the runoff coefficient decreased from 0.32 to 0.11.

[0128] (2) Vegetation restoration: The vegetation coverage on the slope reached 68.3%, and the survival rate of each plant species exceeded 85%, forming a stable grass-shrub complex community with awnless brome, alfalfa and crested wheatgrass as the dominant herbaceous layer and caragana and sea buckthorn as the shrub layer.

[0129] (3) Soil improvement: Soil organic matter content increased by 91.5%, water-stable aggregate content increased by 67.6%, soil bulk density decreased by 12.6%, and soil erosion resistance and water retention capacity were significantly enhanced.

[0130] (4) Slope stability: Soil cohesion increased by 57.0%, internal friction angle increased by 23.9%, disintegration rate decreased by 62.4%, no gully or landslide occurred on the slope, and the safety of the tower foundation was effectively guaranteed.

[0131] All the above key indicators were verified by statistical analysis, and the differences reached a significant level (p<0.05 or p<0.01). This embodiment fully demonstrates that the collaborative governance system and method provided by the present invention can be effectively applied to the soil and water conservation in the tower foundation area of ​​power transmission and transformation projects in the Loess Plateau, and has significant engineering and ecological benefits.

[0132] like Figure 1 As shown, the method for coordinated management of soil and water loss in the tower foundation area of ​​power transmission and transformation projects of the present invention includes the following steps:

[0133] First, topographic and meteorological data of the base area were collected, and the design peak runoff flow was calculated using the inference formula method to determine the layout of the interception and drainage system.

[0134] Secondly, according to the layout, intercepting ditches are laid along the contour lines, and drainage ditches are laid along the direction perpendicular to the contour lines of the slope to connect with the intercepting ditches. Fish scale pits, ecological bags or vegetation pits are laid on the slope between the intercepting ditches and the drainage ditches as micro water collection and retention facilities.

[0135] Then, composted sludge, crushed straw, crushed construction waste, topsoil from the tower base area, and water-retaining agent are mixed in a volume ratio of 1:1:0.5:2.5, and 0.1% polyacrylamide water-retaining agent is added. After being mechanically stirred and mixed evenly, the mixture is laid on the slope and tilled into the topsoil to form a waste-based composite soil improvement layer.

[0136] Finally, herbaceous plants and shrubs are sown on the waste-based composite soil improvement layer to form a grass-shrub composite plant community. Maintenance and management such as covering, watering, and reseeding are carried out until a stable plant community is formed.

[0137] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A collaborative water and soil erosion control system for the tower foundation area of ​​a power transmission and transformation project, characterized in that, include: The micro-topography runoff control unit includes a water interception ditch laid on the upper slope side of the tower base, a drainage ditch laid on the slope surface, and a micro water collection and retention facility laid on the slope surface between the water interception ditch and the drainage ditch. The water interception ditch is laid along the contour line, and the drainage ditch is laid along the direction perpendicular to the contour line of the slope surface and connected to the water interception ditch. The micro water collection and retention facility includes fish scale pits, ecological bags, or vegetation pits. The soil improvement unit is a waste-based composite soil improvement layer laid on the surface of the artificially excavated slope, spoil slope, and the construction disturbance area of ​​the intercepting ditch and drainage ditch in the tower base area. The raw materials of the waste-based composite soil improvement layer consist of composted sludge, crushed straw, crushed construction waste, topsoil stripped from the surface of the tower base area, and water-retaining agent. The vegetation restoration unit consists of a grass-shrub complex plant community planted in the soil improvement unit.

2. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, The micro-topography runoff control unit also includes a stilling basin, which is located at the end of the drainage ditch and connected to the natural ditch. The stilling basin is 1.5m long, 1.0m wide, and 0.8m deep, and the bottom of the basin is paved with 20cm thick stones.

3. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, In the waste-based composite soil improvement layer, the volume ratio of the composted sludge, crushed straw, crushed construction waste, and the topsoil of the tower base area is 1:1:0.5:2.

5. The water-retaining agent is polyacrylamide, and its addition amount is 0.1% of the total volume of the composted sludge, crushed straw, crushed construction waste, and topsoil of the tower base area.

4. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, The thickness of the waste-based composite soil amendment layer is 10cm to 30cm.

5. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, The intercepting ditch has a trapezoidal cross-section, with a bottom width of 0.4m, a depth of 0.5m, a side slope ratio of 1:0.5, and a longitudinal slope of 0.5% to 1.0% at the bottom. It is constructed with M7.5 mortar-grouted rubble masonry and a 10cm thick gravel cushion layer is laid at the bottom of the ditch.

6. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, The drainage ditch is a precast concrete U-shaped channel structure with a width of 0.4m, a depth of 0.35m, a wall thickness of 6cm, and a length of 0.5m for each section. The sections are connected by a socket joint, and the joints are filled with M10 mortar.

7. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, The fish-scale pits are arranged in a triangular pattern along the contour lines, with an opening width of 0.5m and a depth of 0.3m; the planting holes have a diameter of 0.2m and a depth of 0.2m.

8. The system for coordinated water and soil erosion control in the tower foundation area of ​​power transmission and transformation projects according to claim 1, characterized in that, The herbaceous plants in the vegetation restoration unit include awnless brome, alfalfa and crested wheatgrass, and the shrubs include Caragana korshinskii and sea buckthorn.

9. A method for the coordinated management of soil and water loss in the tower foundation area of ​​a power transmission and transformation project for implementing the system described in any one of claims 1 to 8, characterized in that: Collect topographic and meteorological data of the base area, use the inference formula method to calculate the design peak runoff, and determine the layout of the interception and drainage system; According to the layout, intercepting ditches are laid along the contour lines, and drainage ditches are laid along the direction perpendicular to the contour lines of the slope to connect with the intercepting ditches. Fish scale pits, ecological bags or vegetation pits are laid on the slope between the intercepting ditches and the drainage ditches as micro water collection and retention facilities. The composted sludge, crushed straw, crushed construction waste, topsoil stripped from the tower base area, and water-retaining agent are mixed in a volume ratio of 1:1:0.5:2.5, and 0.1% polyacrylamide water-retaining agent is added. After being mechanically stirred and mixed evenly, the mixture is laid on the slope and tilled into the topsoil to form a waste-based composite soil improvement layer. Herbaceous plants and shrubs are sown on the waste-based composite soil improvement layer to form a grass-shrub composite plant community.

10. The method for coordinated management of soil and water loss in the tower foundation area of ​​power transmission and transformation projects according to claim 9, characterized in that, The reasoning formula method uses a design rainfall intensity of 45 mm / h and a runoff coefficient of 0.

55. The herbaceous plants are broadcast sown at a rate of 80 kg / hm² for awnless bromegrass, 30 kg / hm² for alfalfa, and 45 kg / hm² for crested wheatgrass. The shrubs are sown in holes at a depth of 2 cm to 3 cm, with 5 to 8 seeds per hole and a plant spacing of 1.0 m × 1.5 m.

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