A slope reinforcement method based on microbial regulation of root fiber bundle directional cultivation

Abstract

The application discloses a slope reinforcement method based on root fiber bundle directional cultivation of microbial regulation, and belongs to the cross technical field of slope ecological restoration and geotechnical engineering. The method constructs a "microorganism-secretion-configuration-mechanics" whole-chain active regulation system. Specifically, the method comprises the following steps: reversely designing an optimal root fiber bundle configuration according to slope geomechanical parameters; compounding a PMC composite microbial inoculum with branch promoting, secretion regulation, nitrogen fixation and phosphorus release and mineralization functions; realizing directional cultivation of the root configuration through zoned differential inoculation, pre-embedding of degradable directional fiber catheters and in-situ dynamic monitoring. The application improves the root bundle rate to more than 85%, significantly improves the shear strength of the root-soil composite, increases the safety factor of the slope by 0.3-0.5, shortens the construction period, reduces the cost, and realizes efficient, ecological and long-acting reinforcement of the easy-sliding slope.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of slope ecological restoration and geotechnical engineering, specifically involving a slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles. Background Technology

[0002] Ecological slope protection technology is a product of the cross-integration of geotechnical engineering and ecological restoration. Its core lies in using the interaction between plant roots and soil to improve slope stability, thus achieving both ecological benefits and engineering safety.

[0003] Existing technologies generally follow a passive model of "roots first, assessment later, and remediation later," which has significant drawbacks. First, the spatial configuration of the root system cannot be pre-designed and actively controlled based on key mechanical parameters such as the potential slip surface and internal force distribution of the slope, resulting in a low degree of matching between root reinforcement and actual engineering needs, and limited reinforcement efficiency. Second, existing technologies are mostly limited to the improvement of environmental factors such as soil, water, and fertilizer, or rely on the selection of limited plant species, failing to deeply intervene in the micro-physiological and ecological processes of root development. This leads to slow root development, unclear direction of configuration optimization, and difficulty in forming an effective reinforcement system within the time frame required by the project. In addition, existing methods generally lack a quantitative and standardized verification loop for reinforcement effects, often stopping at increasing vegetation coverage rather than substantially enhancing the mechanical properties of the soil and rock. The lack of simultaneous design of root morphology and mechanical enhancement effects casts doubt on the long-term safety and reliability of the project. The fundamental flaw lies in the failure to actively couple the plant-microbe collaboration (PMC) ecological process with the fiber bundle reinforcement mechanics theory. This results in a low natural root bundle formation rate, weak synergistic effect, and limited improvement in shear strength. At the same time, the microbial function is redundant, and its contribution to the anchoring-friction-filling composite mechanism cannot be quantified and precisely controlled. Furthermore, the technology lacks specificity and it is difficult to achieve differentiated and directional cultivation of root configurations based on different risk areas of the slope, resulting in uneven reinforcement effects and insufficient improvement in stability.

[0004] To overcome the aforementioned shortcomings, some existing technologies have emerged that actively guide root architecture, such as influencing root growth direction through localized water and fertilizer supply. While these methods recognize the importance of architecture regulation, their methods remain indirect. Their limitations lie in the single dimension of regulation, lacking synergistic design and precise intervention of the rhizosphere micro-ecosystem, particularly functional microbial communities; secondly, the guidance mechanism lacks deep coupling with slope mechanics models, failing to achieve a reverse mapping from "mechanical objectives" to "growth instructions"; and thirdly, it lacks the ability to dynamically feedback and optimize based on real-time root development status. Therefore, existing technologies still struggle to achieve proactive synergy between ecological restoration processes and soil and rock reinforcement needs at a quantitative and designable level, failing to meet the increasingly stringent requirements of slope engineering for governance efficiency, reinforcement effectiveness, and long-term stability.

[0005] Patent document CN111837909A discloses a "system and method for regulating the root system architecture of slope plants." This system uses a water-conducting pipe with segmented seepage units and a movable water-blocking head to supply water and nutrients to different depths of the slope soil in a differentiated manner. It utilizes the hydrotropism and fertility tropism of plants to induce root growth at a predetermined angle, aiming to improve the root system's slope-stabilizing ability. However, this approach is essentially a passive induction of environmental factors and does not yet incorporate the synergistic effect of plants and microorganisms. Its ability to regulate the intrinsic physiological processes of the root system is limited, and its guiding design is not closely integrated with the quantitative analysis of the specific mechanical model of the slope. Furthermore, it lacks real-time monitoring and dynamic feedback on the root system architecture development itself. Summary of the Invention

[0006] To address the shortcomings of existing ecological slope reinforcement technologies that passively adapt root system configuration to mechanical requirements, this invention provides a method for directional cultivation of root fiber bundles and slope reinforcement based on microbial regulation. This provides an efficient, controllable, and environmentally friendly systematic solution for achieving precise cultivation of root fiber bundle configuration and quantitative improvement of slope mechanical properties.

[0007] To achieve this objective, the following solution is provided: This invention provides a slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles, comprising the following steps: S1. Obtain the geomechanical parameters of the slope through exploration. Based on the geomechanical parameters and fiber bundle shear lag theory, determine the target root fiber bundle configuration parameters for slope reinforcement in reverse. S2. A compound PMC functional bacterial agent containing branching-promoting strains, secretion-regulating strains, nitrogen-fixing and phosphorus-releasing strains, and mineralization-functional strains was prepared and cultured to a final concentration of 10. 9 CFU / mL; S3. Inoculate different risk zones of the slope with PMC functional microbial agent and set up physical guidance structures to promote the growth of plant roots according to the target root fiber bundle configuration parameters. S4. After the root system has been cultivated, test the mechanical properties of the root-soil composite of the slope to verify the reinforcement effect.

[0008] Furthermore, in step S1, the geomechanical parameters include the slip surface dip angle, slip depth, soil internal friction angle, and undisturbed soil cohesion; the target root fiber bundle configuration parameters include root gradation density, branching angle of the taproot and lateral roots, and the preferred spatial orientation of the root system in the slope.

[0009] Furthermore, the root system gradation density has a ratio of 1:5:(20-30) of the number of main roots, lateral roots and fibrous roots, wherein the diameter of the main root is 8-12 mm, the diameter of the lateral root is 2-4 mm, and the diameter of the fibrous root is 0.5-0.8 mm; the branching angle between the main root and the lateral root is 45-60°.

[0010] Furthermore, the preferred spatial orientation is a fan-shaped region with a potential slip surface normal of ±30°.

[0011] Furthermore, in step S2, the branching-promoting strain is Bacillus subtilis, the secretion-regulating strain is arbuscular mycorrhizal fungi, the nitrogen-fixing and phosphorus-releasing strain is nitrogen-fixing bacteria or Bacillus megaterium, and the mineralization-functional strain is Pasteurella multocida; the PMC functional bacterial agent also includes 5% potassium humate as a carbon source synergist.

[0012] Furthermore, in step S2, the ratio of viable bacteria of the branching-promoting strain, the secretion-regulating strain, the nitrogen-fixing and phosphorus-releasing strain, and the mineralization-functional strain is 1:1:(1-2):2.

[0013] Furthermore, in step S3, 10 people were vaccinated in different risk areas. 9 The dosage of PMC functional microbial agent with CFU / mL is: 300 mL / m² in high-risk slope areas. 2 Transition zone 100 mL / m 2 Stable zone 50 mL / m 2 The physical guiding structure is a biodegradable directional fiber conduit pre-embedded in the implantation site.

[0014] Furthermore, the biodegradable directional fiber conduit is made of polylactic acid, has an inner diameter of 3 mm, a guide angle of 45°-50°, a degradation cycle of 12 months, and is also filled with a water-retaining agent and slow-release fertilizer.

[0015] Furthermore, step S3 also includes using microroot canals and distributed fiber optic sensing technology to perform in-situ dynamic monitoring of the root development status, and adjusting the cultivation conditions based on the monitoring results.

[0016] This invention also applies the slope reinforcement method based on microbial-regulated root fiber bundle directional cultivation to steep red clay slopes or shallow landslides in the weathered layer of granite.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves a fundamental shift from experience-based qualitative adaptation to quantitative design based on mechanical models. By combining fiber bundle shear lag theory with specific slope parameters, it enables precise matching between the target root system structure and the mechanical requirements of slope reinforcement, fundamentally resolving the contradiction between the randomness of root system configuration and the certainty of engineering objectives, and significantly improving the pertinence and reliability of reinforcement measures.

[0018] 2. The plant growth regulators secreted by the functional strains with plant-microbe collaboration (PMC) in this invention can directly stimulate the differentiation of lateral root primordia, actively driving the root system to grow according to the designed branches from a physiological level, overcoming the shortcomings of low efficiency and slow speed of simple environmental induction. Among them, the indoleacetic acid (IAA) concentration of Bacillus subtilis is ≥50 mg / L, which promotes the differentiation and growth of lateral root primordia; arbuscular mycorrhizal fungi and other fungi regulate root exudates, which can increase the total sugar content of root exudates by more than 30%, optimizing the rhizosphere environment; the MIP process driven by Pasteurella multocida can generate calcium carbonate cement in situ at the root-soil interface, significantly enhancing the mechanical interlocking and chemical cementation between roots and soil, and improving the interface strength that is difficult to achieve with traditional plant reinforcement; nitrogen-fixing and phosphorus-releasing strains have an effective phosphorus conversion rate of 40%, which can provide continuous nutrients for plants and functional microbial communities, ensuring the sustainability of high-intensity directional cultivation on barren slopes.

[0019] 3. This invention provides a physical channel for early root growth by pre-embedding biodegradable directional fiber vascular bundles. Especially during the critical periods of seed germination and root tip extension, it can guide the root tip to extend towards the target spatial region such as the slip surface normal, ensuring the accurate realization of the design configuration at the spatial level and greatly improving the success rate of root spatial orientation.

[0020] 4. The in-situ dynamic monitoring and feedback control of this invention uses micro-root canals and fiber optic sensors to monitor root bundle formation rate and soil strain in real time. When development deviates from the design target, intervention measures such as secondary inoculant enhancement can be initiated immediately, realizing visualization, controllability, and intelligence of the cultivation process, ensuring that the final bundle formation rate consistently reaches a high level of over 85%. Simultaneously, differentiated cultivation in slope risk zones can significantly improve the overall effectiveness and economy of the reinforcement system, avoiding resource waste or localized failure caused by averaging treatment.

[0021] 5. Through the synergistic effect of various technical features, this invention ultimately achieves a significant quantitative improvement in the shear strength index of the root-soil composite, resulting in a substantial increase in the slope safety factor and meeting the stability requirements under harsh working conditions. Simultaneously, it eliminates the need for rigid materials such as reinforced concrete, achieving a green reinforcement project. Its core reverse design-microbial regulation-physical guidance framework can adjust specific parameters according to different geological conditions, making it suitable for treating various slippery slopes, from red clay to weathered granite layers, demonstrating enormous application potential. Detailed Implementation

[0022] The present invention will be further described below with reference to preferred embodiments. The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values. These ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed herein.

[0023] The following examples utilize geological drilling (drilling depth ≥ 1.5 times the potential slip surface depth) and in-situ shear tests (per 500 m). 2 One test point was set up to obtain the geomechanical parameters of the slope, including: the dip angle of the slip surface α (accuracy ±1°), the slip depth H (accuracy ±0.1m), and the cohesion of the undisturbed soil c0 (accuracy ±1kPa); and the internal friction angle φ0 (accuracy ±0.5°), soil particle size distribution, and natural moisture content were also obtained. The following embodiments are based on fiber bundle shear lag theory and geomechanical parameters, using formula d c = √[4T / (πτ max )] Calculate the critical diameter of the root fiber bundle (d) c This ensures that the fiber bundles can withstand the shear force of the sliding soil; where T is the tensile strength of a single root (determined through indoor tensile tests, T≥150N for the main root of a shrub), and τ... max The maximum shear stress of the soil is calculated from φ0 and the self-weight of the overlying soil layer. Based on the calculation results, determine the ratio and branching angles of the main root (d1), lateral roots (d2), and fibrous roots (d3). This invention delineates risk zones based on the slope stability coefficient (Fs) assessment results: High-risk areas: Fs < 1.0, with a high probability of potential slippage (such as the toe of the slope and the exposed area of ​​the slip surface). Transition zone: 1.0≤Fs≤1.2, in a critical state of stability (such as the upper part of the slope). Stable zone: Fs > 1.2, no significant slip risk (e.g., hilltop platform); In the following examples, the method for preparing PMC functional microbial agents is as follows: Bacillus subtilis (CGMCC1.1630) and Bacillus megaterium (CGMCC1.1741): Inoculated into LB medium (10 g / L peptone, 5 g / L yeast extract, 10 g / L NaCl, pH 7.0), and cultured with shaking at 28℃ and 200 rpm for 24 h until the bacterial concentration reached 10. 9CFU / mL, detection of IAA content ≥50 mg / L (using high performance liquid chromatography, HPLC-1260, Agilent Technologies, USA); Arbuscular mycorrhizal fungi (BGCXJ04): Inoculated onto PDA medium (potato 200 g / L, glucose 20 g / L, agar 15 g / L, pH 5.8), cultured at 25℃ in the dark for 7 days, collected the spore suspension, and adjusted the concentration to 10. 8 spores / mL, indicating an increase of more than 30% in total sugar content in secretions (using the phenol-sulfuric acid method). Nitrogen-fixing bacteria (CGMCC1.2393): Inoculated on Ashby nitrogen-free medium (mannitol 10 g / L, KH2PO4 0.2 g / L, MgSO4) (Use 0.2 g / L 7H2O, pH 7.2) and incubate at 30℃ for 48 h until the bacterial concentration reaches 10. 9 CFU / mL, the effective phosphorus conversion rate was detected to be 40% (using the molybdenum antimony colorimetric method).

[0024] Pasteurella multocida (CGMCC1.3687): Inoculated onto urea medium (urea 20 g / L, yeast extract 15 g / L, Ni... 2+ 10 μmol / L, Mn 2+ Incubate at 10 μmol / L (pH 8.0-9.0) with shaking at 30℃ and 180 rpm for 36 h until the bacterial concentration reaches 10. 9 CFU / mL, urease activity ≥150 U / mL (using phenol-hypochlorite colorimetric method); In the following examples, the compounded PMC functional bacterial agent was dispensed into sterile polyethylene bottles (500 mL / bottle), stored at 4 ℃, and had a shelf life of ≤7 days. The following examples, after inoculation with PMC functional microbial agents and carbon source supplementation, targeted the regulation of flavonoid concentration in root exudates to ≥15 μg / g; regulated the content of organic acids (citric acid and oxalic acid) to maintain the pH value of root soil at 5.5-6.5; and regulated the amino acid content to increase to ≥8 mg / g. In the following examples, planting holes (30 cm in diameter and 60 cm in depth) are dug at 2 m × 2 m intervals during planting. In high-risk areas, the spacing is increased to 1.5 m × 1.5 m. A 10 cm thick layer of well-rotted organic fertilizer (organic matter content ≥ 45%) is laid at the bottom of the hole, and the middle layer is filled with improved soil (original soil, 2% peat moss and 1% vermiculite). A 5 cm layer is reserved on the surface for inoculation with fungal agents. In the following examples, a root analyzer (WinRHIZOPro2022, Regent, Canada) was used to scan the microcanals to record root bundle formation rate, branching angle, and diameter distribution. When the bundle formation rate was <70%, 50 mL / well was applied to the corresponding area at a concentration of 10. 8 Enhanced bacterial agent with CFU / mL.

[0025] Unless otherwise specified, the experimental methods in the following embodiments are conventional methods, performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0026] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0027] Example 1 This embodiment provides a slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles.

[0028] This method was applied to a 18 m high, 55° red clay slope located at a newly built substation in Wuping County, Fujian Province. The potential slip surface depth reached 3.2 m. The original soil was red clay with a clay content of 65%, a cohesion c0 of 22 kPa, an internal friction angle φ0 of 18°, and an initial safety factor Fs of 0.95 (which decreased to 0.88 under heavy rainfall conditions), indicating a potential landslide hazard. The area has a subtropical monsoon climate with an annual rainfall of approximately 1400 mm, with the rainy season mainly concentrated from June to August. The steps included are as follows: S1. Based on the fiber bundle shear retardation theory, the geomechanical parameters of the red clay slope obtained through surveying are calculated to determine the main root diameter d1 as 12 mm and the arrangement density as 3 roots / m. 2 The lateral root diameter d2 is 4 mm, and the arrangement density is 15 roots / m. 2 The root diameter d3 is 0.8 mm, and the arrangement density is 300 roots / m. 2 The ratio of graded density is 1:5:20, the branching angle β between the main root and the lateral root is 50°, and the root system develops in a fan-shaped area along the normal (inclination angle 38°) ±30° of the slip surface. S2. A PMC functional bacterial agent was prepared by compounding Bacillus subtilis (CGMCC 1.1630), arbuscular mycorrhizal fungi (BGCXJ04), nitrogen-fixing bacteria (CGMCC 1.2393), and Pasteurella multocida (CGMCC 1.3687) at a live bacteria ratio of 1:1:1:2. A 5% potassium humate solution was added as a carbon source supplement, and the mixture was cultured to a final concentration of 10. 9 CFU / mL; S3. Divide the slope into a high-risk zone (slope toe), a transition zone (slope middle), and a stable zone (slope crest), and apply 300 mL, 100 mL, and 50 mL of inoculant per well, respectively. 9 Inoculate with CFU / mL, and prepare 200 mL, 150 mL, and 100 mL of 0.5% urea solution respectively; use Amorpha fruticosa and Paspalum distichum for mixed sowing. In the planting hole, symmetrically bury 6 polylactic acid biodegradable directional fiber vascular bundles with a degradation period of 12 months along the slip surface as a physical guiding structure. The top of the vascular bundle is 10 cm from the hole opening, the bottom is inserted 30 cm into the improved soil, the length is 50 cm, the inner diameter is 3 mm, and the guide angle is 45°. Add a water-retaining agent and slow-release fertilizer mixture with a mass ratio of 1:1, where the water-retaining agent is acrylamide-potassium acrylate copolymer, and the slow-release fertilizer is NPK=15-10-15; per 30 m 2 One micro-root canal is installed, buried 0.5 m below the potential slip surface, every 100 m 2 One set of fiber optic sensors was installed, and the monitoring frequency was increased to twice a week during the rainy season. During the cultivation process, the root bundle rate was monitored, the root bundle rate, branch angle and diameter distribution were recorded monthly, and an in-situ direct shear test was conducted once every 3 months to determine the root-soil composite cohesion c and internal friction angle φ. S4. After 6 months of cultivation, the root-soil composite reinforcement effect was verified again through in-situ direct shear test.

[0029] The reinforcement effect was verified using standard indicators, including: c≥35 kPa, φ≥5°, fiber bundle synergy coefficient≥1.8; slope safety factor Fs≥1.3 (calculated using the simplified Bishop method); vegetation coverage ≥80%, and root bundle formation rate ≥85%.

[0030] The slope reinforcement method described in this embodiment resulted in a root system configuration that highly matched the design objectives, with a root bundle rate of 87%, an average taproot depth of 1.8m, and an average angle between the taproot and lateral roots of 52°. This optimized configuration significantly improved the mechanical properties of the root-soil composite, increasing the cohesion c to 58 kPa (a 163.6% increase from the initial value), the internal friction angle φ to 24° (a 33.3% increase from the initial value), and the fiber bundle synergy coefficient to 2.1. Finally, the slope's safety factor Fs under heavy rainfall conditions increased to 1.45 (a 64.8% increase from the initial value), with no signs of slippage, fundamentally improving stability, and the reinforcement effect fully meeting the expected goals. The vegetation coverage reached 85%, the soil organic matter content increased from 1.2% to 2.8%, and soil erosion decreased by 70%.

[0031] Example 2 This embodiment provides a slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles.

[0032] This method was applied to a shallow landslide in a weathered granite layer, 8 m high and with a slope of 45°. This slope was a construction site for a power transmission line project in Anxi County, Fujian Province. The soil layer thickness was 0.8-1.2 m, with a gravel content of 40%. The potential slip surface depth was 0.6 m, the undisturbed soil c0 was 18 kPa, φ0 was 22°, and the initial safety factor Fs was 1.02 (0.98 during the rainy season), indicating a risk of shallow landslide. The method includes the following steps: S1. Geomechanical parameters of the completely weathered granite layer were obtained through surveying. Based on the fiber bundle shear retardation theory, the diameter d1 of the main root was determined to be 8 mm, and the arrangement density was 3 roots / m. 2 The lateral root diameter d2 is 2 mm, and the arrangement density is 15 roots / m. 2 The root diameter d3 is 0.5 mm, and the arrangement density is 300 roots / m. 2 The density ratio of the graded root system is 1:5:30, the branching angle β between the main root and the lateral root is 60°, and the root system develops in a fan-shaped area along the normal direction (inclination angle 38°) ±30° of the slip surface. S2. A PMC functional microbial agent was prepared by compounding Bacillus subtilis (CGMCC 1.1630), arbuscular mycorrhizal fungi (BGCXJ04), Bacillus megaterium (CGMCC 1.1741), and Diplococcus pasteurella (CGMCC 1.3687) at a live bacteria ratio of 1:1:2:2. A 5% potassium humate solution was added as a carbon source supplement, and the mixture was cultured to a final concentration of 10. 9 CFU / mL; S3. Divide the slope into a high-risk zone (slope toe), a transition zone (slope middle), and a stable zone (slope crest). Apply 300 mL, 100 mL, and 50 mL of inoculant per well, respectively. 9 CFU / mL) inoculated, and 200 mL, 150 mL, and 100 mL of 0.5% urea solution were prepared respectively; a mixture of edamame and switchgrass was selected for sowing. In the planting hole, six polylactic acid biodegradable directional fiber vascular bundles with a degradation period of 12 months were symmetrically buried along the slip surface as a physical guiding structure. The top of the vascular bundle was 10 cm from the hole opening, and the bottom end was inserted 30 cm into the improved soil. The bundles were 50 cm long with a 50° bevel angle. A 1:1 mixture of water-retaining agent and slow-release fertilizer was added, where the water-retaining agent was acrylamide-potassium acrylate copolymer, and the slow-release fertilizer was NPK=15-10-15. 0.5% sodium carboxymethyl cellulose was added as a binder. 30 m 2 One micro-root canal is installed, buried 0.5 m below the potential slip surface, every 100 m 2One set of fiber optic sensors was installed, and the monitoring frequency was increased to twice a week during the rainy season. During the cultivation process, the root bundle rate was monitored, the root bundle rate, branch angle and diameter distribution were recorded monthly, and an in-situ direct shear test was conducted once every 3 months to determine the root-soil composite cohesion c and internal friction angle φ. S4. After 3 months of cultivation, the root-soil composite reinforcement effect was verified again through in-situ direct shear test.

[0033] The root system configuration formed by the slope reinforcement method described in this embodiment is highly consistent with the design target, with a root bundle rate of 86% and a fibrous root density of 450 roots / m². 2 The biomass of the shallow root system (0-0.6m) increased by 40% compared to the traditional scheme; this optimized configuration significantly improved the mechanical properties of the root-soil composite, with cohesion c increasing to 59 kPa (227.8% higher than the initial value), internal friction angle φ increasing to 28° (27.3% higher than the initial value), and topsoil erosion resistance increasing by 65%; finally, the safety factor Fs of the slope under heavy rain conditions increased to 1.42, with no signs of shallow slippage, and the stability was fundamentally improved, with the reinforcement effect fully achieving the expected goals; the mixed-seeded vegetation coverage reached 90%, the soil organic matter content increased from 1.2% to 2.8%, and soil erosion decreased by 70%.

[0034] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles, characterized in that, Includes the following steps: S1. Obtain the geomechanical parameters of the slope through exploration. Based on the geomechanical parameters and fiber bundle shear lag theory, determine the target root fiber bundle configuration parameters for slope reinforcement in reverse. S2. A compound PMC functional bacterial agent containing branching-promoting strains, secretion-regulating strains, nitrogen-fixing and phosphorus-releasing strains, and mineralization-functional strains was prepared and cultured to a final concentration of 10. 9 CFU / mL; S3. Inoculate different risk zones of the slope with PMC functional microbial agent and set up physical guidance structures to promote the growth of plant roots according to the target root fiber bundle configuration parameters. S4. After the root system has been cultivated, test the mechanical properties of the root-soil composite of the slope to verify the reinforcement effect.

2. The slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 1, characterized in that, In step S1, the geomechanical parameters include the slip surface dip angle, slip depth, soil internal friction angle, and undisturbed soil cohesion; the target root fiber bundle configuration parameters include root gradation density, branching angle of the taproot and lateral roots, and the preferred spatial orientation of the root system in the slope.

3. The slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 2, characterized in that, The root system gradation density is the ratio of the number of main roots, lateral roots and fibrous roots in the ratio of 1:5:(20-30), wherein the diameter of the main root is 10-12 mm, the diameter of the lateral root is 2-4 mm, and the diameter of the fibrous root is 0.5-0.8 mm; the branching angle between the main root and the lateral root is 45°-60°.

4. The slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 2, characterized in that, The preferred spatial orientation is a fan-shaped region within ±30° of the potential slip surface normal.

5. The slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 1, characterized in that, In step S2, the branching-promoting strain is Bacillus subtilis, the secretion-regulating strain is arbuscular mycorrhizal fungi, the nitrogen-fixing and phosphorus-releasing strain is nitrogen-fixing bacteria or Bacillus megaterium, and the mineralization-functional strain is Pasteurella multocida; the PMC functional bacterial agent also includes 5% potassium humate as a carbon source synergist.

6. A slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 1, characterized in that, In step S2, the ratio of viable bacteria of the branching strain, secretion-regulating strain, nitrogen-fixing and phosphorus-releasing strain to mineralization-functional strain is 1:1:(1-2):

2.

7. The slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 1, characterized in that, In step S3, 10 people were vaccinated in different risk areas. 9 The dosage of PMC functional microbial agent with CFU / mL is: 300 mL / m² in high-risk slope areas. 2 Transition zone 100 mL / m 2 Stable zone 50 mL / m 2 The physical guiding structure is a biodegradable directional fiber conduit pre-embedded in the implantation site.

8. The slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 7, characterized in that, The biodegradable directional fiber conduit is made of polylactic acid, has an inner diameter of 3 mm, a guide angle of 45°-50°, a degradation cycle of 12 months, and is also filled with a water-retaining agent and slow-release fertilizer.

9. A slope reinforcement method based on microbial-regulated directional cultivation of root fiber bundles according to claim 1, characterized in that, Step S3 also includes using microroot canals and distributed fiber optic sensing technology to perform in-situ dynamic monitoring of the root development status, and adjusting the cultivation conditions based on the monitoring results.

10. The slope reinforcement method based on microbial regulation of root fiber bundle directional cultivation as described in any one of claims 1-9 is applied to steep red clay slopes or shallow landslides in the weathered layer of granite.