A grouting anchor rod suitable for microbial-induced mineralization reinforcement and an application method thereof

Abstract

The application discloses a grouting anchor rod suitable for microbial induced mineralization reinforcement and an application method thereof, and the grouting anchor rod comprises a sleeve, an anchor head, a hollow grout stopping plug, an arched backing plate and a nut, and the anchor head is detachably installed at an anchoring end of the sleeve. The sleeve and the hollow anchor rod are combined to form independent grouting channels which do not interfere with each other, grouting material and biological nutrient liquid containing urease-producing bacterial flora are injected into a borehole, pore water around the anchor hole and the injected nutrient liquid are utilized to induce calcium carbonate precipitation in an anchoring area, CaCO3 crystals are deposited at an anchoring interface, pores are filled, the combination strength of the grout and the rock-soil is improved, the peeling of the anchoring layer is effectively prevented, and the interface bonding performance is enhanced; the microbial induced mineralization technology is combined with the anchor rod physical reinforcement system, multi-scale structure-biological-environmental synergistic reinforcement is realized, and macroscopic structure stability and microscopic particle consolidation are unified, so that the slope support effect of enhancement, long-term stability and ecological friendliness is achieved.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering and slope reinforcement technology, specifically relating to a grouting anchor suitable for microbial-induced mineralization reinforcement and its application method. Background Technology

[0002] With the rapid development of mountain highways, railways, and water conservancy and hydropower projects, slope stability issues have become increasingly prominent. Traditional slope protection methods mainly include rigid reinforcement methods such as shotcrete, anchor bolt (anchor cable) support, anti-slide piles, and frame beam support. These traditional support methods have the following shortcomings:

[0003] Excessive stiffness and insufficient flexibility can easily lead to localized stress concentration, resulting in problems such as cracking, detachment, and corrosion during long-term service. The bonding with the soil is limited, and the support effect relies on mechanical embedding, making it difficult to achieve reinforcement of the soil's microstructure. The environmental cost is high, as the construction process requires a large amount of concrete, steel bars, and other materials, resulting in high carbon emissions, which does not conform to the concept of green engineering. Insufficient durability means that in high humidity, high salinity, or freeze-thaw environments, the interface between traditional anchor bolts and grout is prone to degradation, leading to a decline in anchoring performance.

[0004] In recent years, microbially induced calcium carbonate precipitation (MICP) technology has received widespread attention in the field of soil and rock reinforcement due to its green and environmentally friendly characteristics and self-healing properties. MICP can generate calcium carbonate crystals through the hydrolysis of urea, cementing the particles into a monolithic structure and improving soil strength and impermeability. However, the application of microbial mineralization alone in complex terrain or steep slopes has problems such as limited mineralization depth, insufficient mechanical enhancement effect, and difficulties in construction control.

[0005] Combining anchor bolt (anchor cable) support with bio-induced calcium carbonate precipitation technology can improve the bonding strength between the grout and the soil. In the existing technology, the anchor bolt structure is prone to clogging the grouting hole after grouting, which makes it difficult to inject biological nutrient solution. Even if it can be injected from the outside, the distribution of biological nutrient solution is uneven, resulting in the interface bonding performance not meeting the construction requirements and making it difficult to maintain later. After long-term use, the slope support effect will gradually weaken.

[0006] Therefore, it is necessary to research and develop a grouting anchor suitable for microbial-induced mineralization reinforcement and its application method to solve the above problems. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a grouting anchor suitable for microbial-induced mineralization reinforcement and its application method. By combining a casing with a hollow anchor, an independent and non-interfering grouting channel is formed. Grouting material and a biological nutrient solution containing urease-producing bacteria are injected into the borehole. The pore water around the anchor hole and the injected nutrient solution induce calcium carbonate precipitation in the anchoring zone. CaCO3 crystals are deposited at the anchoring interface, filling pores, improving the bonding strength between the grout and the soil / rock, effectively preventing anchoring layer peeling, and enhancing interfacial adhesion performance. This solves the problems of insufficient slope support strength and diminished protection effect in existing technologies.

[0008] The embodiments of the present invention provide the following technical solutions:

[0009] A grouting anchor bolt suitable for microbial-induced mineralization reinforcement includes a casing, an anchor head, a hollow grout stopper, an arched pad, and a nut. The anchor head is detachably installed at the anchoring end of the casing. The hollow grout stopper, the arched pad, and the nut are arranged sequentially along the axial direction of the casing at the end away from the anchor head. A hollow anchor bolt is fixedly connected inside the casing by a support plate. Multiple flexible capsules are sleeved on the hollow anchor bolt. Multiple nozzles are evenly surrounding the outside of the flexible capsules. Multiple injection holes corresponding to the nozzles are distributed through the casing. A check valve is provided at the input end of each nozzle. An extension tube is integrally provided on the outer surface of the casing corresponding to the outside of each injection hole.

[0010] A through-type first channel is provided at the axis of the hollow anchor rod. Multiple second channels are provided in a ring array outside the first channel. Both the first and second channels are distributed along the axial direction of the hollow anchor rod, and the length of the second channel is less than that of the first channel, so that the second channel only penetrates the end face of the hollow anchor rod at the end away from the anchor head. An input through hole and an output through hole are provided on the outer wall of the hollow anchor rod, which penetrate to the second channel. The input through hole is set in the installation coverage area of ​​the hollow grout stop plug, so that the inner cavity of the hollow grout stop plug is connected to the second channel. The output through hole is set in the installation coverage area of ​​the flexible bladder, so that the inner cavity of the flexible bladder is connected to the second channel. An interface is provided through the tail end of the hollow grout stop plug.

[0011] An overflow channel is provided at the center of the anchor head, and a diverging pipe network is connected to the outside of the overflow channel. The input end of the overflow channel is connected to the first channel.

[0012] Preferably, a buffer spring is sleeved on the outside of the hollow anchor rod, one end of the buffer spring abuts against the side of the support plate, and the other end abuts against the grouting piston. The grouting piston is slidably sleeved on the outside of the hollow anchor rod, and the outer side of the grouting piston slides in cooperation with the inner wall of the sleeve. The grouting piston is made of flexible rubber material.

[0013] Preferably, the hollow anchor rod is fitted with an interface two at the end away from the anchor head, and the interior of the interface two is set in a stepped shape to block the second channel. A sealing gasket is provided between the inner side of the interface two and the end of the hollow anchor rod so that the output end of the interface two is only connected to the first channel. A threaded cover plate is detachably installed at the input end of the interface two.

[0014] Preferably, the hollow grout stopper includes two hemispherical steel pads, which are slidably fitted on the outside of the hollow anchor rod. A flexible sealing ring is provided at the connection between the hemispherical steel pad and the hollow anchor rod. The flexible sealing ring covers both ends of the input through hole. The two hemispherical steel pads are arranged opposite each other and seamlessly welded, forming a hollow spherical cavity inside. A blocking outer ring is fixedly connected at the weld of the two hemispherical steel pads.

[0015] The arched pad is fastened to the outside of one of the hemispherical steel pads. After fastening, the side of the arched pad fits against the outer blocking ring of the hemispherical steel pad. A first sealing ring is filled at the joint between the arched pad and the outer blocking ring.

[0016] The interface 1 passes through a hemispherical steel pad away from the anchor head, and a second sealing ring is provided between the interface 1 and the through hole on the hemispherical steel pad.

[0017] Preferably, a slot is provided on one side of the arched pad, and an interface is embedded inside the slot, with a ball valve installed inside the interface.

[0018] A positioning block is fixedly connected to the side of the outer ring of the barrier near the arched pad, and a positioning groove is provided on the side of the arched pad to engage with the positioning block.

[0019] Preferably, the outer wall of the sleeve is fixedly connected with a spiral reinforcing band, and the number of spiral reinforcing bands is set to multiple, with multiple nozzles corresponding to the same flexible capsule forming a group, and the multiple spiral reinforcing bands are spaced apart between the extension tubes corresponding to each two adjacent groups of nozzles.

[0020] Preferably, the sleeve and the hollow anchor rod are coaxially distributed, and a strain gauge sensor is provided between the sleeve and the hollow anchor rod. A strain gauge sensor is also fixedly connected to the outside of the sleeve.

[0021] Preferably, the second input end of the interface is connected to the grouting pump through a delivery pipe; the first input end of the interface is connected to the pump through a delivery pipe, and the input end of the pump is connected to the mixing container, with three injection pipes provided on the top of the mixing container.

[0022] Preferably, the interface is equipped with an intelligent monitoring module, the connection end of which is electrically connected to a microcontroller. The input and output ends of the microcontroller are respectively equipped with an A / D converter and a D / A converter. The pump is electrically connected to the D / A converter. The connection end of the D / A converter is electrically connected to an early warning indicator. The connection end of the microcontroller is equipped with a display.

[0023] The intelligent monitoring module includes a flow rate sensor, a thermometer, and a pH sensor, which are used to sense the flow rate, volume, temperature, and pH value of the fluid passing through the interface. The strain gauge sensor, flow rate sensor, thermometer, and pH sensor are all electrically connected to the A / D converter.

[0024] This invention also provides an application method for grouting anchors suitable for microbial-induced mineralization reinforcement. The grouting anchors are applied to geotechnical engineering and slope reinforcement. The slope reinforcement steps are as follows:

[0025] S1. Slope pre-maintenance and shaping: A longitudinal section is constructed by excavating a trench on the slope, and a retaining wall is built within the trench.

[0026] S2. Selection of anchor bolts and preparation for grouting: Drill holes in the retaining wall and slope rock and soil according to the design requirements. After drilling is completed, insert the selected grouting anchor bolts into the holes.

[0027] S3. Grouting into the borehole. Start the grouting pump to extract grout and pressurize it into the first channel. The grout enters the borehole through the overflow channel and the divergence pipeline network, filling the space enclosed by the borehole, casing, hollow grout stop plug and arched pad.

[0028] S4. Injecting microbial nutrient solution into the borehole: After the slurry has solidified, prepare and inject the microbial nutrient solution, which includes the following steps:

[0029] S4.1. Inject microorganisms, nutrient solution and oxygen into the mixing container, mix thoroughly to prepare a microbial nutrient solution containing bacterial flora.

[0030] S4.2 Start the pump to extract the microbial nutrient solution containing bacteria from the mixing container, pressurize and pump it into the second channel, and let it flow out through the output hole, flexible capsule, nozzle and spray hole, and combine with the anchoring grout. Let it stand for 12-48 hours at intervals.

[0031] S4.3. Inject reaction trigger into the second channel, and it flows out through the output through hole, flexible capsule, nozzle and jet hole, combining with the anchoring grout. The pore water around the anchor hole and the injected nutrient solution induce calcium carbonate precipitation in the anchoring area.

[0032] S5. Microbial-induced mineralization maintenance: Regularly inject nutrient solution or bacterial solution, and regularly backwash.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. By combining the casing and hollow anchor bolts, an independent and non-interfering grouting channel is formed. Grouting material and biological nutrient solution containing urease-producing bacteria are injected into the borehole. The pore water around the anchor hole and the injected nutrient solution induce calcium carbonate precipitation in the anchoring zone. CaCO3 crystals are deposited at the anchoring interface, filling pores, improving the bonding strength between the grout and the soil, effectively preventing the anchoring layer from peeling off, and enhancing the interfacial bonding performance. The combination of microbial induced mineralization technology and the anchor bolt physical reinforcement system achieves multi-scale synergistic reinforcement of structure, biology, and environment. It unifies macroscopic structural stability and microscopic particle consolidation, achieving enhanced, long-lasting stability, and eco-friendly slope support effects.

[0035] 2. By combining with an intelligent monitoring system, real-time monitoring and early warning can be achieved, which can be used for the reinforcement and protection of high-risk slopes. The grouting anchor provided by this invention can be applied to fractured rock, sandy soil and high-permeability slopes, and can resist the effects of humidity, salt corrosion and freeze-thaw cycles; the microbial system has self-healing ability, and can induce mineralization repair again when micro-cracks appear, thus extending the effective support life of the device. Attached Figure Description

[0036] Figure 1 This is a first-view perspective perspective view of the overall structure of the grouting anchor provided by the present invention.

[0037] Figure 2 This is a second-view perspective perspective view of the overall structure of the grouting anchor provided by the present invention.

[0038] Figure 3 This is a front view of the grouting anchor provided by the present invention.

[0039] Figure 4 This is a cross-sectional view of the grouting anchor provided by the present invention.

[0040] Figure 5 This is a half-sectional view of the grouting anchor provided by the present invention.

[0041] Figure 6 This is a first-view exploded view of the grouting anchor provided by the present invention.

[0042] Figure 7 This is a second-view exploded view of the grouting anchor provided by the present invention.

[0043] Figure 8 This is a perspective view of the hollow anchor rod of the present invention.

[0044] Figure 9 This is a cross-sectional view of the hollow anchor rod of the present invention.

[0045] Figure 10The control principle diagram of the intelligent control system provided by the present invention.

[0046] Figure 11 This is a schematic diagram of the grouting anchor provided by the present invention applied to slope reinforcement.

[0047] Marked in the image:

[0048] 1. Sleeve; 2. Anchor head; 3. Hollow grout stop plug; 301. Hemispherical steel pad; 302. Blocking outer ring; 4. Arched pad; 5. Nut; 6. Support plate; 7. Hollow anchor rod; 8. Flexible bladder; 9. Nozzle; 10. Extension tube; 11. First channel; 12. Second channel; 13. Input through hole; 14. Output through hole; 15. Interface 1; 16. Overflow channel; 17. Diverging pipe network; 18. Buffer spring; 19. Grouting piston; 20. Interface 2; 21. Slot; 22. Ball valve; 23. Spiral reinforcing belt; 24. Strain gauge sensor; 25. Mixing container; 26. Intelligent monitoring module; 261. Flow rate sensor; 262. Thermometer; 263. pH sensor; 27. Microcontroller; 28. Early warning device; 29. ​​Display. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0050] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for 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 invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can refer to a detachable connection: it can be a mechanical connection; it can also be an indirect connection through an intermediate medium, or it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] like Figures 1 to 9The grouting anchor bolt shown is suitable for microbial-induced mineralization reinforcement. It includes a sleeve 1, an anchor head 2, a hollow grout-stopping plug 3, an arched pad 4, and a nut 5. The anchor head 2 is detachably installed at the anchoring end of the sleeve 1. The hollow grout-stopping plug 3, the arched pad 4, and the nut 5 are arranged sequentially along the axial direction of the sleeve 1 at the end away from the anchor head 2. A hollow anchor bolt 7 is fixedly connected inside the sleeve 1 via a support plate 6. The sleeve 1 and the hollow anchor bolt 7 must ensure long-term usability (corrosion resistance, non-clogging, maintainability) and provide a suitable living environment for microorganisms while delivering reagents to the anchoring area. For example, corrosion-resistant engineering plastics (HDPE, PVDF, PTFE), 316L stainless steel, or stainless steel composite pipes with plastic linings can be used. Furthermore, the inner surfaces of the sleeve 1 and the hollow anchor bolt 7 are smooth to reduce biofilm adhesion and scaling. Multiple flexible capsules 8 are sleeved on the hollow anchor rod 7. Multiple nozzles 9 are evenly surrounding the outer side of the flexible capsules 8. Multiple injection holes, corresponding one-to-one with the nozzles 9, are penetrating the sleeve 1. A check valve is provided at the input end of the nozzle 9. An extension tube 10 is integrally provided on the outer surface of the sleeve 1, corresponding to the outer side of each injection hole. The flexible capsules 8 and the hollow anchor rod 7 are tightly connected, with no gaps at the joint. The internal channels of the injection holes and the extension tubes 10 are connected, and the nozzles 9 slide in conjunction with the injection holes and the internal channels of the extension tubes 10.

[0053] A through-type first channel 11 is provided at the axis of the hollow anchor rod 7. Multiple second channels 12 are arranged in a ring array outside the first channel 11. Both the first channel 11 and the second channel 12 are distributed along the axial direction of the hollow anchor rod 7, and the length of the second channel 12 is less than the length of the first channel 11, so that the second channel 12 only penetrates the end face of the hollow anchor rod 7 at the end furthest from the anchor head 2. An input through-hole 13 and an output through-hole 14 are provided on the outer wall of the hollow anchor rod 7, penetrating to the second channel 12. The input through-hole 13 corresponds to the installation coverage area of ​​the hollow grout stop plug 3, allowing the inner cavity of the hollow grout stop plug 3 to communicate with the second channel 12. The output through-hole 14 corresponds to the installation coverage area of ​​the flexible capsule 8, allowing the inner cavity of the flexible capsule 8 to communicate with the second channel 12. An interface 15 is provided through the tail end of the hollow grout stop plug 3. The first channel 11 is used to transport mortar, and the second channel 12 is used to transport the microbial-induced mixture. In the embodiment provided by this invention, the inner diameter of the first channel 11 is larger than the inner diameter of the second channel 12. Furthermore, the cross-sectional shape of the first channel 11 is set to rectangular, and the corners of the rectangular cross-section of the first channel 11 are rounded. The cross-sectional shape of the second channel 12 is set to strip.

[0054] An overflow channel 16 is provided at the center of the anchor head 2, and the outer side of the overflow channel 16 is connected to the divergence pipe network 17. The input end of the overflow channel 16 is connected to the first channel 11. The anchor head 2 is designed as a detachable structure, such as being threadedly connected to the sleeve 1. During construction, the anchor head 2 can be selected according to the actual working conditions, such as a pier anchor, a tapered anchor, a threaded anchor, a self-drilling anchor, or an expansion shell anchor.

[0055] Furthermore, in the above scheme, a buffer spring 18 is sleeved on the outside of the hollow anchor rod 7. One end of the buffer spring 18 abuts against the side of the support plate 6, and the other end abuts against the grouting piston 19. The grouting piston 19 is slidably sleeved on the outside of the hollow anchor rod 7, and the outer side of the grouting piston 19 slides in cooperation with the inner wall of the sleeve 1. The grouting piston 19 is made of flexible rubber material.

[0056] Furthermore, in the above scheme, the end of the hollow anchor rod 7 away from the anchor head 2 is fitted with an interface 20, and the interior of the interface 20 is set in a stepped shape to block the second channel 12. A sealing gasket is provided between the inner side of the interface 20 and the end of the hollow anchor rod 7, so that the output end of the interface 20 is only connected to the first channel 11. A threaded cover plate is detachably installed at the input end of the interface 20.

[0057] Furthermore, in the above scheme, the hollow grout stopper 3 includes two hemispherical steel pads 301. The hemispherical steel pads 301 are slidably fitted on the outside of the hollow anchor rod 7, and a flexible sealing ring is provided at the connection between the hemispherical steel pads 301 and the hollow anchor rod 7. The flexible sealing ring covers the two ends of the input through hole 13. The two hemispherical steel pads 301 are arranged opposite each other and seamlessly welded, forming a hollow spherical cavity inside. A blocking outer ring 302 is fixedly connected at the weld of the two hemispherical steel pads 301.

[0058] The arched pad 4 is fastened to the outside of one of the hemispherical steel pads 301. After fastening, the side of the arched pad 4 is in contact with the outer blocking ring 302 of the hemispherical steel pad 301. The joint between the arched pad 4 and the outer blocking ring 302 is filled with a first sealing ring.

[0059] Interface 15 penetrates a hemispherical steel pad 301 away from the anchor head 2, and a second sealing ring is provided between interface 15 and the through hole on the hemispherical steel pad 301.

[0060] The first sealing ring, the second sealing ring, the flexible sealing ring, and the sealing gasket are all made of rubber.

[0061] Furthermore, in the above scheme, a slot 21 is provided on one side of the arched pad 4, and an interface 15 is embedded inside the slot 21. A ball valve 22 is provided inside the interface 15.

[0062] A positioning block is fixedly connected to the side of the outer ring 302 near the arched pad 4, and a positioning groove is provided on the side of the arched pad 4 to engage with the positioning block.

[0063] Furthermore, in the above scheme, a spiral reinforcing band 23 is fixedly connected to the outer wall of the sleeve 1, and the number of spiral reinforcing bands 23 is set to multiple, with multiple nozzles 9 corresponding to the same flexible capsule 8 forming a group. The multiple spiral reinforcing bands 23 are spaced apart between the extension pipes 10 corresponding to each two adjacent groups of nozzles 9. This increases the anchoring force between the anchor rod and the soil, improving the slope reinforcement strength and stability, and does not interfere with the normal operation of the nozzles 9.

[0064] Furthermore, in the above scheme, the sleeve 1 and the hollow anchor rod 7 are coaxially distributed, and a strain gauge sensor 24 is installed between the sleeve 1 and the hollow anchor rod 7. A strain gauge sensor 24 is also fixedly connected to the outside of the sleeve 1. During installation, the strain gauge sensor 24 requires proper surface treatment, temperature compensation, and waterproof protection. The strain-axial force relationship is calibrated through a pull-out test to ensure reliable and effective monitoring results. The strain gauge sensor 24 measures the axial strain of the sleeve 1 and the hollow anchor rod 7, and calculates the anchor rod axial force accordingly to determine the anchoring effect. The initial strain value of the strain gauge sensor 24 reflects whether the initial tension has reached the design value. If, during long-term monitoring, the axial force continuously decreases, suddenly drops, or is inconsistent across measuring points along the length, it indicates the presence of loosening, slippage, or deterioration of the anchoring end adhesion.

[0065] Furthermore, in the above scheme, the input end of interface 20 is connected to a grouting pump via a delivery pipe; the grouting pump extracts slurry a and pressurizes it before pumping it into the first channel 11. The input end of interface 15 is connected to a pump via a delivery pipe, and the input end of the pump is connected to a mixing container 25. Three injection pipes are installed on the top of the mixing container 25. The three injection pipes inject microorganisms b, nutrient solution c, and oxygen d into the mixing container 25 respectively. After mixing, the microbial nutrient solution containing the bacterial community is injected into the second channel 12. An intelligent monitoring module 26 is installed inside interface 15, such as... Figure 10 As shown, the intelligent monitoring module 26 is electrically connected to a microcontroller 27. The microcontroller 27 has an A / D converter and a D / A converter at its input and output terminals, respectively. The pump is electrically connected to the D / A converter. The D / A converter is electrically connected to an early warning indicator 28. The microcontroller 27 has a display 29 at its connection terminal.

[0066] The intelligent monitoring module 26 includes a flow rate sensor 261, a thermometer 262, and a pH sensor 263, which are used to sense the flow rate, flow volume, temperature, and pH value of the fluid passing through the interface 15, respectively. The strain gauge sensor 24, the flow rate sensor 261, the thermometer 262, and the pH sensor 263 are all electrically connected to the A / D converter to realize automated injection / alarm.

[0067] This invention also provides an application method for grouting anchors suitable for microbial-induced mineralization reinforcement. Grouting anchors are used in geotechnical engineering and slope reinforcement, such as... Figure 11 As shown, the slope reinforcement steps are as follows:

[0068] S1. Slope pre-maintenance and shaping: A longitudinal section is constructed by excavating a trench on the slope, and a retaining wall is built within the trench.

[0069] S2. Anchor Selection and Grouting Preparation: Drill holes in the retaining wall and slope soil according to design requirements. After drilling, insert the selected grouting anchors into the holes. After inserting the grouting anchors, continuously apply external force to the anchors to ensure that the arched pad 4 fits snugly against the retaining wall. Further, the retaining walls can be fixed together.

[0070] S3. Grouting into the borehole; start the grouting pump to extract grout a and pressurize it into the first channel 11. Grout a enters the borehole through the overflow channel 16 and the divergence network 17, filling the space enclosed by the borehole, casing 1, hollow grout stop plug 3, and arched pad 4. To prevent the nozzle 9 from being blocked during grouting, a backwashing device can be installed. In the embodiments provided by the present invention, before the grouting anchor is inserted into the borehole, an isolation film is wrapped around the outside of the extension pipe 10; or a biological solution and oxygen are injected simultaneously during the grouting process.

[0071] S4. Injecting Microbial Nutrient Solution into the Borehole: After grout a has solidified, prepare and inject the microbial nutrient solution. The goal of this step is to form a controlled microbial-induced mineralization zone around the grouting anchor, enhancing the anchoring interface with the surrounding soil without causing groundwater or environmental pollution, pipe blockage, or equipment failure. The design must consider microbial survival, nutrient / calcium source delivery, aeration and retention, monitoring and sampling, and maintainability. Specifically, it includes the following steps:

[0072] S4.1. Inject microorganism b, nutrient solution c, and oxygen d into mixing container 25. Microorganism b and nutrient solution c are prepared in a predetermined ratio, with the volume fraction of microorganism b being 5%-20%. Under oxygen supply conditions, they are thoroughly mixed to form an injectable microbial reaction solution. The ratio of microorganism b, nutrient solution c, and oxygen d depends on the specific conditions of the slope soil and the required anchoring. The suitable pH value of the microbial nutrient solution used as the injection fluid is set to 7-8.5, and is adjusted and measured for stability before injection. Specifically, the bacterial community used in this embodiment is a urease-producing bacterial community (such as Bacillus pasteurii). This microbial nutrient solution is a low-nutrient buffer solution carrying bacterial cells, which can be prepared by adding a small amount of yeast extract of the bacterial community to a low-concentration salt buffer solution, avoiding the outbreak of non-target microorganisms caused by high nutrition. The ratio of biological liquid and grouting pressure can be adjusted according to different geological conditions to achieve integrated mechanical strengthening, seepage prevention, corrosion prevention, and ecological restoration.

[0073] Common parameters for Bacillus pasteurii injection reinforcement in slope soil reinforcement are as follows:

[0074] Microbial concentration using OD 600 Or bacterial liquid integral characterization:

[0075] OD 600 The range is 0.5-1.5 (0.8-1.2 is most commonly used in engineering).

[0076] The bacterial liquid fraction ranges from 5% to 20% (w / v).

[0077] The bacterial cell concentration range is 10. 7 -10 8 cells / mL.

[0078] When used for anchoring reinforcement and slope strengthening, a bacterial solution ratio of 10%-15% is recommended to balance permeability and sedimentation efficiency.

[0079] In engineering, the most common and stable volume ratios of microbial solutions and nutrient solutions are as follows:

[0080] Microbial solution: nutrient solution = 1:1-3. Common combinations include: microbial solution: nutrient solution = 1:1 (fast sedimentation, high reinforcement efficiency); microbial solution: nutrient solution = 1:2 (good permeability and uniformity); microbial solution: nutrient solution = 1:3 (for low-permeability soils, avoids clogging).

[0081] Typical nutrient solution composition includes urea: 0.5-1.0 mol / L; CaCl2: 0.25-0.75 mol / L; and a slowing agent (NH4Cl / NaHCO2): optional.

[0082] The oxygen supply is generally not fixed. The oxygen supply methods include bubbling, oxygenation, and oxygen enrichment. Mixing and stirring can maintain aerobic metabolism and increase urease activity.

[0083] S4.2. Start the pump to extract the microbial nutrient solution containing bacteria from the mixing container 25, pressurize and pump it into the second channel 12, and flow out through the output hole 14, flexible capsule 8, nozzle 9 and spray hole, combining with the anchoring grout. Allow it to stand for 12-48 hours at intervals. During injection, use low pressure and low speed (to avoid pore rupture and washing away of bacteria). In cold environments, consider pipeline insulation or electric heating to maintain bacterial activity (the design insulation range depends on the target bacteria, usually 15℃-35℃ is optimal).

[0084] S4.3. Inject reaction triggers into the second channel 12, preferably using urea as the reaction trigger, and minimize the supply of additional organic carbon to avoid inducing the growth of other microorganisms. The reaction triggers flow out through the output hole 14, flexible capsule 8, nozzle 9 and injection hole, and combine with the anchoring grout. The pore water around the anchor hole and the injected nutrient solution induce calcium carbonate precipitation in the anchoring area; CaCO3 crystals are generated, forming a crystal bridging structure between the anchoring grout and the surrounding soil particles, enhancing the interfacial adhesion and overall strength.

[0085] S5. Microbial-induced mineralization maintenance: Regularly inject nutrient solution or bacterial solution for long-term maintenance or remineralization to achieve long-term autotrophic mineralization enhancement; periodic backwashing. For example, install backwashing pipelines and outlets after every N cycles. Before circulation or long-term shutdown, treat the equipment with an antibacterial or flushing program (fresh water + mild disinfectant), but ensure it does not cause unacceptable impact on the soil ecology. Use larger pore size dispersed effluent, periodic backwashing, low-speed injection, intermittent injection (to allow for bacterial retention time), and appropriate nutrients to avoid eutrophication and excessive biofilm growth.

[0086] Specifically, the microbial solution is injected in multiple stages, rather than all at once. The following are common microbial solution injection ranges at the anchor bolt / grouting hole scale.

[0087] When the diameter of the anchor hole is 20-30mm, the injection volume of the microbial solution is 0.5-2L / time.

[0088] When the diameter of the anchor hole is 30-50mm, the injection volume of the microbial solution is 1-5L / time.

[0089] When the length of the grouting anchor is >3m, the amount of microbial solution injected is 3-10L / time.

[0090] In the specific embodiments provided by the present invention:

[0091] The bacterial concentration in the injected microbial nutrient solution was set to 10. 7 -10 8 CFU / mL.

[0092] The concentration of urea used as a reaction trigger was set to 0.25-1.0 M.

[0093] Ca in microbial nutrient solution 2+ The (CaCl2) concentration should be set to 0.25-0.5M, or other calcium sources should be selected to reduce the Cl concentration. - .

[0094] The injection pressure range of the microbial nutrient solution is set to 0.1–0.5 MPa.

[0095] The retention time after injection of microbial nutrient solution was set to 24 hours for bacterial culture; and 72 hours for injection of reaction trigger.

[0096] The number of replenishment cycles N before backflushing is set to 10, or until the target CaCO3 / mechanical parameters are achieved.

[0097] The above are merely specific embodiments of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A grouting anchor suitable for microbial-induced mineralization reinforcement, comprising a sleeve (1), an anchor head (2), a hollow grouting stopper (3), an arched backing plate (4) and a nut (5), the anchor head (2) being detachably installed at an anchoring end of the sleeve (1), the hollow grouting stopper (3), the arched backing plate (4) and the nut (5) being sequentially arranged along an axial direction of the sleeve (1) at an end of the sleeve (1) away from the anchor head (2), characterized in that: The sleeve (1) is fixedly connected with a hollow anchor rod (7) inside through a support plate (6), a plurality of flexible capsules (8) are sleeved on the hollow anchor rod (7), a plurality of nozzles (9) are uniformly arranged outside the flexible capsules (8), a plurality of injection holes corresponding to the nozzles (9) are arranged on the sleeve (1), a check valve is arranged at the input end of the nozzle (9), an extension pipe (10) is integrally arranged outside the sleeve (1) and corresponds to each injection hole. The hollow anchor rod (7) is provided with a first through channel (11) at the shaft center, a plurality of second channels (12) are annularly arranged outside the first channel (11), the first channel (11) and the second channel (12) are arranged along the axial direction of the hollow anchor rod (7), the length of the second channel (12) is smaller than the length of the first channel (11), so that the second channel (12) only penetrates the end surface of the hollow anchor rod (7) at the end away from the anchor head (2), the hollow anchor rod (7) is provided with an input through hole (13) and an output through hole (14) which penetrate the second channel (12), the input through hole (13) is arranged corresponding to the installation coverage area of the hollow grouting stopper (3), so that the inner cavity of the hollow grouting stopper (3) is communicated with the second channel (12), the output through hole (14) is arranged corresponding to the installation coverage area of the flexible capsule (8), so that the inner cavity of the flexible capsule (8) is communicated with the second channel (12), the hollow grouting stopper (3) is provided with a connector I (15) penetratingly arranged at the tail end. The anchor head (2) is provided with an overflow channel (16) at the shaft center, and the overflow channel (16) is communicated with a divergent pipe network (17) outside.

2. A grouting anchor rod suitable for microbial induced mineralization reinforcement according to claim 1, characterized in that: The hollow anchor rod (7) is sleeved with a buffer spring (18) outside, one end of the buffer spring (18) abuts against the side surface of the support plate (6), and the other end abuts against a grouting piston (19), the grouting piston (19) is slidingly sleeved outside the hollow anchor rod (7), and the outer side surface of the grouting piston (19) is slidingly matched with the inner wall of the sleeve (1), the grouting piston (19) is made of flexible rubber material.

3. The grouting anchor rod suitable for microbial-induced mineralization reinforcement according to claim 1, characterized in that: The hollow anchor rod (7) is sleeved with a connector II (20) at the end away from the anchor head (2), the inside of the connector II (20) is arranged in a stepped shape for blocking the second channel (12), and a sealing gasket is arranged between the inside of the connector II (20) and the end of the hollow anchor rod (7), so that the output end of the connector II (20) is only communicated with the first channel (11), and a threaded cover plate is detachably arranged at the input end of the connector II (20).

4. A groutable anchor rod suitable for use in microbial induced mineralization reinforcement according to claim 3, characterized in that: The hollow grouting stopper (3) comprises two half-spherical steel pads (301), the half-spherical steel pads (301) are slidingly matched outside the hollow anchor rod (7), and a flexible sealing ring is arranged at the connection between the half-spherical steel pads (301) and the hollow anchor rod (7), the flexible sealing ring covers the two end regions of the input through hole (13), the two half-spherical steel pads (301) are oppositely arranged and are welded without seams, and a hollow spherical cavity is formed inside, a blocking outer ring (302) is fixedly connected at the weld seam between the two half-spherical steel pads (301). The arched backing plate (4) is buckled outside one of the half-spherical steel backing plates (301), the side of the buckled arched backing plate (4) is attached to the blocking outer ring (302) of the half-spherical steel backing plate (301), and the joint between the arched backing plate (4) and the blocking outer ring (302) is filled with a first sealing ring; The interface one (15) penetrates one of the half-spherical steel backing plates (301) away from the anchor head (2), and a second sealing ring is arranged between the interface one (15) and the penetrating hole on the half-spherical steel backing plate (301).

5. A groutable anchor rod suitable for use in microbial induced mineralization reinforcement according to claim 4, characterized in that: The arched backing plate (4) is provided with a clamping groove (21) on one side, and the interface one (15) is embedded in the inner side of the clamping groove (21), and the interface one (15) is provided with a ball valve (22) inside. The blocking outer ring (302) is fixedly connected with a positioning block on the side close to the arched backing plate (4), and a positioning groove is arranged on the side of the arched backing plate (4) to match the positioning block.

6. A groutable anchor rod suitable for use in microbial induced mineralization reinforcement according to claim 1, characterized in that: The sleeve (1) is fixedly connected with a spiral reinforcing belt (23) on the outer wall, and the number of the spiral reinforcing belts (23) is multiple, and the multiple spray heads (9) corresponding to the same flexible bag body (8) are taken as a group, and the multiple spiral reinforcing belts (23) are arranged at intervals between the extension pipes (10) corresponding to every adjacent two groups of spray heads (9).

7. A groutable anchor rod suitable for use in microbial induced mineralization reinforcement according to claim 1, characterized in that: The sleeve (1) and the hollow anchor rod (7) are coaxially distributed, and a strain gauge sensor (24) is arranged between the sleeve (1) and the hollow anchor rod (7), and the strain gauge sensor (24) is also fixedly connected to the outer side of the sleeve (1).

8. A grouting anchor rod suitable for microbial induced mineralization reinforcement according to claim 3, characterized in that: The input end of the interface two (20) is connected with a grouting pump through a conveying pipe; the input end of the interface one (15) is connected with a pump through a conveying pipe, and the input end of the pump is communicated with a mixing container (25), and the top of the mixing container (25) is provided with three injection pipelines.

9. A groutable anchor rod suitable for use in microbial induced mineralization reinforcement according to claim 8, characterized in that: The interface one (15) is provided with an intelligent monitoring module (26), and the connection end of the intelligent monitoring module (26) is electrically connected with a single-chip microcomputer (27), and the input end and the output end of the single-chip microcomputer (27) are respectively provided with an A / D converter and a D / A converter, the pump is electrically connected with the D / A converter, the connection end of the D / A converter is electrically connected with a pre-warning indicator (28), and the connection end of the single-chip microcomputer (27) is provided with a display (29). The intelligent monitoring module (26) includes a flow rate sensor (261), a thermometer (262) and a pH value sensor (263), which are respectively used for sensing the flow rate, flow, temperature and pH value data of the fluid substance in the interface one (15), and the strain gauge sensor (24), the flow rate sensor (261), the thermometer (262) and the pH value sensor (263) are electrically connected with the A / D converter.

10. The application method of the grouting anchor rod for microbial induced mineralization reinforcement according to any one of claims 1-9, which is applied to geotechnical engineering and slope reinforcement, characterized in that: The slope reinforcement steps are as follows: S1, slope pre-maintenance and shaping: grooving is constructed on the slope to form a longitudinal section, and a slope retaining wall is built in the groove; S2, anchor rod selection and grouting preparation: drill holes in the slope retaining wall and the slope soil according to the design requirements, and insert the selected grouting anchor rod into the drill hole after the drilling is completed; S3, grouting into the borehole; starting the grouting pump to draw the slurry and pump it into the first channel (11), the slurry enters the borehole through the overflow channel (16) and the divergent pipe network (17), and fills the space enclosed by the borehole, the casing (1), the hollow grout stopper (3) and the arched pad (4); S4, injecting microbial nutrient solution into the borehole: after the slurry solidifies, the microbial nutrient solution is prepared and injected, which specifically includes the following steps: S4.1, injecting microorganisms, nutrient solution and oxygen into the mixing container (25) and mixing thoroughly to prepare the microbial nutrient solution containing bacterial flora; S4.2, starting the pump to draw the microbial nutrient solution containing bacterial flora in the mixing container (25) and pump it into the second channel (12) under pressure, and then it flows out through the output through hole (14), the flexible sac (8), the nozzle (9) and the injection hole, combines with the anchoring slurry, and is left for 12-48 hours; S4.3, injecting a reaction trigger into the second channel (12), which flows out through the output through hole (14), the flexible sac (8), the nozzle (9) and the injection hole, combines with the anchoring slurry, and induces calcium carbonate precipitation in the anchoring area using the pore water around the anchor hole and the injected nutrient solution; S5, microbial induced mineralization maintenance: regular injection of nutrient solution or bacterial solution and regular backwashing.

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