Non-power-failure main material replacement method suitable for power transmission tower damaged by rockfall in mountainous area

Abstract

The invention relates to the technical field of power transmission line operation and maintenance, and discloses an uninterruptible power main material replacement method suitable for a mountainous area rockfall damaged power transmission tower, which comprises the following steps: firstly, establishing a protective bent frame with a mechanical trigger in a dangerous rock area, and linking a tower body locking module through a signal cable to construct an induction linkage defense system; a bypass channel is established by using the hoop lined with the friction coating and the rigid-flexible coupling prestress node, and the damaged main material load is smoothly transferred to the auxiliary main material and then the auxiliary main material is dismantled; then a new main material of the prefabricated micro-channel is installed, epoxy structural adhesive is injected, and gapless connection between the new component and the old component is achieved; and finally, dismantling the temporary facility after the glue solution is cured. Through mechanical linkage defense, friction type lossless connection and a micro-channel glue injection technology, the problems of lack of operation safety early warning, tower damage caused by reinforcement and poor connection anti-vibration performance are solved, and the operation safety without power failure is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of power transmission line operation and maintenance technology, specifically a method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption. Background Technology

[0002] Transmission towers, serving as the backbone of power transmission, are widely distributed in mountainous regions. In the complex geological environment of mountainous areas, rockfalls and rockfalls are among the main natural disasters causing damage to the main materials of these towers. To ensure the continuity of power supply, in-situ replacement of damaged main materials without interrupting power is currently the mainstream maintenance strategy. However, existing uninterrupted replacement techniques still have technical limitations when facing mountainous environments with a continuous risk of rockfalls.

[0003] First, the existing safety protection system lacks a physical linkage mechanism between the hazard source and the work site. Relying solely on electronic monitoring equipment is susceptible to interference or failure in the strong electromagnetic environment of mountainous areas, and cannot achieve an immediate mechanical interlock response in the event of a sudden secondary rockfall, resulting in significant safety risks to workers and towers under temporary support.

[0004] Secondly, during load transfer, the conventionally used steel clamps, due to their hard contact with the tower body, are highly susceptible to damaging the original galvanized anti-corrosion layer on the tower material's surface. Simultaneously, the existing rigid jacking method lacks flexible buffering, and the sudden stress changes during load switching can easily trigger localized instability in the damaged tower.

[0005] Finally, due to machining tolerances, assembly gaps are unavoidable at the bolt connections between new and old components. Under long-term wind vibration conditions in mountainous areas, these point-contact connections are prone to fretting wear and loosening. The lack of effective gap-filling and interface fusion methods makes it difficult to guarantee the overall stiffness and fatigue resistance of the repaired tower. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for replacing main materials of power transmission towers damaged by rockfalls in mountainous areas without power interruption. This method solves the problems of electronic monitoring equipment being susceptible to interference and having a delayed response in mountainous operating environments, damage to the anti-corrosion layer of tower materials caused by traditional clamp load transfer and easy instability, and insufficient wind vibration resistance due to assembly gaps between new and old components.

[0007] To address the above problems, this invention provides a method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, comprising the following steps:

[0008] S1. Drill holes on the upslope side of the tower to inject modified static fracturing agent to pre-remove the rock mass that is prone to cracking, and establish a rigid protective frame; install mechanical displacement triggers on the rigid protective frame and extend a signal transmission cable to the damaged tower leg, thereby constructing an induction linkage defense system around the work area.

[0009] S2. Under the protection of the induction linkage defense system constructed in step S1, wedge-shaped clamps with friction-type coatings are installed at the nodes at both ends of the damaged main material section, and secondary main materials and rigid-flexible coupling prestressed nodes are installed in parallel between the hanging points of the wedge-shaped clamps; the signal transmission cable is connected to the spring locking module connected in series on the auxiliary steel wire rope, and the tension of the auxiliary steel wire rope is adjusted to make the tension of the steel wire rope in a defense state ready to be triggered, thus completing the establishment of the dual rigid-flexible reinforcement system;

[0010] S3. Adjust the rigid-flexible coupling prestressed nodes to completely transfer the load borne by the damaged main material to the secondary main material; after confirming that the load path switching is completed, remove the damaged main material to create an installation space;

[0011] S4. Hoist the new main material with pre-fabricated microchannel mesh and injection holes on the flange face in the installation space, and apply the initial tightening torque; use microchannel injection to inject in-situ curing microchannel injection special epoxy structural adhesive, let it stand under pressure until the adhesive initially sets, and then tighten the bolts to achieve a gapless connection between the new main material and the original tower body.

[0012] S5. After the injected in-situ curing microchannel injection special epoxy structural adhesive has fully cured and reached the design strength, perform anti-corrosion treatment on the connection area; finally, complete the system disassembly in the order of first releasing the load of the auxiliary steel wire rope and the main sub-material, and then removing the clamps and linkage defense facilities.

[0013] By adopting the above technical solutions, the following effects are achieved due to the use of inductive linkage defense, friction-type non-destructive connection, and microchannel injection technology:

[0014] Purely mechanical linkage defense: A physical connection channel is established between the mechanical displacement trigger and the signal transmission cable. When a dangerous rock impacts the support structure, it directly triggers the spring locking module at the tower body. This purely mechanical structure avoids interference from the strong electromagnetic field in mountainous areas on electronic sensors, ensuring the reliability of early warning and protective actions.

[0015] Non-destructive load transfer: The micro-roughness of the friction-type coating provides a high static friction coefficient. Combined with the disc spring assembly of the rigid-flexible coupling node, the load is smoothly transferred to the secondary main material, avoiding the damage and stress concentration of the tower material's galvanized layer caused by the hard contact of traditional clamps.

[0016] Zero-gap vibration-resistant connection: The microchannel mesh guides the epoxy structural adhesive to uniformly fill the flange surface and bolt holes. After curing, the point contact is transformed into a surface contact, which improves the joint's shear stiffness and resistance to wind vibration fatigue.

[0017] Preferably, the modified static rock fracturing agent is prepared by mixing component A, component B, and water, with the mass ratio of water to the total mass of components A and B being 28%-32%. The chemical composition of component A, by mass percentage, includes: calcium oxide 75.0%-82.0%, silicon dioxide 6.0%-9.0%, aluminum oxide 2.0%-4.0%, anhydrous gypsum 9.0%-11.5%, and sodium fluorosilicate 0.5%-1.0%. Component B includes a polycarboxylate superplasticizer and an anhydrous citric acid retarder, with the mass of the polycarboxylate superplasticizer being 0.8%-1.2% of the total mass of component A, and the mass of the anhydrous citric acid retarder being 0.15%-0.25% of the total mass of component A.

[0018] By adopting the above technical solution, this modified static fracturing agent achieves controllable fracturing through chemical regulation:

[0019] Expansion source: High content of calcium oxide hydrates to form calcium hydroxide, generating an expansion pressure of 30-50 MPa, which damages the rock structure.

[0020] Rate regulation: Sodium fluorosilicate and anhydrous gypsum work synergistically to regulate the crystal growth rate; anhydrous citric acid prolongs the induction period by chelating calcium ions, preventing blowouts caused by excessively rapid reaction.

[0021] Enhanced penetration: Polycarboxylate superplasticizers disperse particles through steric hindrance, allowing the slurry to maintain high fluidity even at low water-cement ratios, thus fully filling micro-fractures in the rock and improving the fracturing effect.

[0022] Preferably, the preparation method of component A of the modified static fracturing agent for rock fracturing is as follows: limestone, clay and gypsum are mixed in stoichiometric ratio and calcined at 1400℃-1450℃ for 2.0-2.5 hours to obtain clinker; after cooling, the clinker is mixed with sodium fluorosilicate and ground to a specific surface area of ​​350-400m² / kg.

[0023] By adopting the above technical solutions, high-temperature calcination ensures the complete development of calcium oxide crystals and reduces the fluctuation of reactivity caused by lattice defects; controlling the grinding specific surface area balances the hydration reaction rate and slurry density, ensuring a stable output of expansion pressure.

[0024] Preferably, the friction coating is prepared by arc spraying, using Q235 low carbon steel plate as the substrate and pure aluminum wire as the spraying material; the parameters are controlled as follows: spraying voltage 28V-32V, spraying current 180A-220A, spraying distance 150mm-200mm, and compressed air pressure 0.5MPa-0.7MPa; the resulting coating thickness is 200μm-300μm, and the surface roughness Ra is 12.5μm-25.0μm.

[0025] By adopting the above technical solution, the pure aluminum coating, as a soft metal medium, undergoes plastic deformation under the action of pre-tightening force, filling the micro-pits on the contact surface and greatly increasing the actual contact area; the specific roughness range provides a stable high coefficient of friction, ensuring the anti-slip capability of the clamp under heavy load.

[0026] Preferably, the in-situ curing microchannel injection-specific epoxy structural adhesive is composed of component A and component B mixed in a mass ratio of 2:1-3:1; component A is made from raw materials containing the following parts by mass: 100.0 parts of bisphenol A type epoxy resin, 8.0-12.0 parts of carboxyl-terminated nitrile rubber, 15.0-20.0 parts of reactive diluent C12-C14 alkyl glycidyl ether, and 2.0-3.0 parts of fumed silica; component B is made from raw materials containing the following parts by mass: 35.0-45.0 parts of modified alicyclic amine curing agent, 2.0-4.0 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 1.0-1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane.

[0027] By adopting the above technical solution, this epoxy structural adhesive is adapted to field microchannel injection conditions through molecular structure design:

[0028] Toughening and impact resistance: The reaction between carboxyl-terminated nitrile rubber and epoxy resin forms an "island structure". When the rubber particles are subjected to stress, they induce crazing and absorb energy, which improves the ability of the rubber layer to withstand the impact of falling rocks and wind vibration loads.

[0029] Rheology control: Reactive diluents reduce the viscosity of the system to accommodate microchannel injection, while fumed silica utilizes thixotropy to prevent sagging on vertical surfaces, ensuring full dispensing.

[0030] Moisture and heat durability: γ-glycidoxypropyltrimethoxysilane acts as a coupling agent to form chemical bonds at the interface between the colloidal and metal, preventing interface delamination in humid mountain environments.

[0031] Preferably, the preparation method of the in-situ curing microchannel injection-specific epoxy structural adhesive includes: preparing component A: stirring bisphenol A type epoxy resin and carboxyl-terminated butadiene-acrylonitrile rubber at 60℃-70℃ for 30-40 minutes for pre-reaction, adding reactive diluent and fumed silica after cooling, and dispersing at 1500r / min-2000r / min for 20-30 minutes under vacuum conditions of -0.095MPa to -0.098MPa; preparing component B: stirring modified alicyclic amine curing agent, 2,4,6-tris(dimethylaminomethyl)phenol and γ-glycidoxypropyltrimethoxysilane at low speed at room temperature for 10-15 minutes until a homogeneous system is formed.

[0032] By adopting the above technical solutions, the pre-reaction process ensures chemical contact between the rubber toughening agent and the matrix resin, avoiding phase separation caused by physical blending; the vacuum high-speed dispersion process effectively removes microbubbles, eliminates stress concentration points inside the cured adhesive layer, and ensures the mechanical strength and homogeneity of the epoxy structural adhesive.

[0033] This invention provides a method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without interrupting power supply. It has the following beneficial effects:

[0034] 1. This invention solves the problem of electronic monitoring equipment being susceptible to interference and having a delayed response in mountainous operating environments by establishing a physical linkage mechanism between the mechanical displacement trigger and the signal transmission cable. It utilizes the displacement generated by the impact of a rockfall on the support frame to directly pull the spring locking module at the tower body. Without the need for external power supply, it can lock the auxiliary reinforcement system instantly before the impact force of falling rocks reaches the tower, thus providing reliable physical safety protection for construction personnel and the tower structure during uninterrupted power supply operations.

[0035] 2. This invention utilizes a wedge-shaped clamp with an inner lining of arc-sprayed friction-type coating in conjunction with a rigid-flexible coupling prestressed node to achieve smooth and lossless load transfer. The friction-type coating provides high static friction by increasing the micro-roughness of the contact surface, avoiding damage to the original galvanized anti-corrosion layer of the tower material caused by hard contact with traditional steel clamps. The disc spring assembly in the rigid-flexible coupling node can absorb the impact energy during load switching and temporary support processes, preventing the risk of local instability of the tower due to sudden stress changes.

[0036] 3. This invention employs a process of prefabricating microchannel mesh on the flange surface and injecting epoxy structural adhesive, which eliminates the assembly gap at the connection between new and old components. The highly permeable epoxy structural adhesive fills the bolt holes and flange mating surfaces under pressure. After curing, it transforms the traditional bolt point contact force into a mixed surface contact force of adhesive and bolt, improving the joint's shear stiffness and wind vibration fatigue resistance, and enabling it to adapt to harsh working conditions such as high wind speeds and potential rockfall vibrations in mountainous areas. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to embodiments, comparative examples, and test examples. 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.

[0038] Preparation Examples 1 to 9:

[0039] Preparation Example 1:

[0040] This preparation example provides a modified static fracturing agent for rock fracturing, comprising the following steps:

[0041] Limestone, clay, and gypsum were mixed in stoichiometric proportions and calcined in a rotary kiln at 1400℃ for 2.5 hours to obtain clinker. After cooling, the clinker was mixed with sodium fluorosilicate stabilizer and ground in a ball mill to a specific surface area of ​​350 m² / g. 2 / kg, to obtain component A; the chemical composition of component A by mass percentage is: calcium oxide 75.0%, silicon dioxide 9.0%, aluminum oxide 4.0%, anhydrous gypsum 11.5%, sodium fluorosilicate 0.5%; prepare component B with high-efficiency water-reducing agent (polycarboxylate) and retarder (anhydrous citric acid) in proportion, wherein the mass of high-efficiency water-reducing agent is 0.8% of the total mass of component A, and the mass of retarder is 0.15% of the total mass of component A; during construction, mix component A and component B, add water at a mass of 28% of the total mass of components A and B, and mechanically stir for 5 minutes to form a slurry.

[0042] Preparation Example 2:

[0043] This preparation example provides a modified static fracturing agent for rock fracturing, comprising the following steps:

[0044] Limestone, clay, and gypsum were mixed in stoichiometric proportions and calcined in a rotary kiln at 1425℃ for 2.2 hours to obtain clinker. After cooling, the clinker was mixed with sodium fluorosilicate stabilizer and ground in a ball mill to a specific surface area of ​​375 m² / g. 2 / kg, to obtain component A; the chemical composition of component A by mass percentage is: calcium oxide 78.5%, silicon dioxide 7.5%, aluminum oxide 3.0%, anhydrous gypsum 10.2%, sodium fluorosilicate 0.8%; prepare component B with high-efficiency water-reducing agent and retarder according to the proportion, wherein the mass of high-efficiency water-reducing agent is 1.0% of the total mass of component A, and the mass of retarder is 0.20% of the total mass of component A; during construction, mix component A and component B, add water at a mass of 30% of the total mass of components A and B, and mechanically stir for 4 minutes to form a slurry.

[0045] Preparation Example 3:

[0046] This preparation example provides a modified static fracturing agent for rock fracturing, comprising the following steps:

[0047] Limestone, clay, and gypsum were mixed in stoichiometric proportions and calcined in a rotary kiln at 1450℃ for 2.0 hours to obtain clinker. After cooling, the clinker was mixed with sodium fluorosilicate stabilizer and then ground in a ball mill to a specific surface area of ​​400 m². 2 / kg, to obtain component A; the chemical composition of component A by mass percentage is: calcium oxide 82.0%, silicon dioxide 6.0%, aluminum oxide 2.0%, anhydrous gypsum 9.0%, sodium fluorosilicate 1.0%; prepare component B with high-efficiency water-reducing agent and retarder according to the proportion, wherein the mass of high-efficiency water-reducing agent is 1.2% of the total mass of component A, and the mass of retarder is 0.25% of the total mass of component A; during construction, mix component A and component B, add water at a mass of 32% of the total mass of components A and B, and mechanically stir for 3 minutes to form a slurry.

[0048] Preparation Example 4:

[0049] This preparation example provides an in-situ curing microchannel injection-specific epoxy structural adhesive, including the following steps:

[0050] Preparation of Component A: Heat 100.0 parts by weight of bisphenol A type epoxy resin to 60℃, add 8.0 parts by weight of carboxyl-terminated butadiene-acrylonitrile rubber, and stir at 500 r / min for 40 minutes for pre-reaction; cool to 35℃, add 15.0 parts by weight of reactive diluent C12-C14 alkyl glycidyl ether and 2.0 parts by weight of fumed silica, and disperse at 1500 r / min for 30 minutes under vacuum of -0.095 MPa using a planetary mixer until no bubbles are present and the filler is uniformly dispersed; Preparation of Component B: Mix 35.0 parts by weight of modified alicyclic amine curing agent with 2.0 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol and 1.0 parts by weight of γ-glycidyl etheroxypropyltrimethoxysilane at room temperature and stir at low speed (200 r / min) for 15 minutes until a homogeneous system is formed; When using, mix Component A and Component B at a mass ratio of 2:1.

[0051] Preparation Example 5:

[0052] This preparation example provides an in-situ curing microchannel injection-specific epoxy structural adhesive, including the following steps:

[0053] Preparation of Component A: Heat 100.0 parts by weight of bisphenol A type epoxy resin to 65℃, add 10.0 parts by weight of carboxyl-terminated butadiene-acrylonitrile rubber, and stir at 650 r / min for 35 minutes for pre-reaction; cool to 35℃, add 17.5 parts by weight of reactive diluent C12-C14 alkyl glycidyl ether and 2.5 parts by weight of fumed silica, and disperse at 1750 r / min for 25 minutes under vacuum of -0.096 MPa using a planetary mixer until no bubbles are present and the filler is uniformly dispersed; Preparation of Component B: Mix 40.0 parts by weight of modified alicyclic amine curing agent with 3.0 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol and 1.2 parts by weight of γ-glycidyl etheroxypropyltrimethoxysilane at room temperature and stir at low speed (250 r / min) for 12 minutes until a homogeneous system is formed; When using, mix Component A and Component B at a mass ratio of 2.5:1.

[0054] Preparation Example 6:

[0055] This preparation example provides an in-situ curing microchannel injection-specific epoxy structural adhesive, including the following steps:

[0056] Preparation of Component A: Heat 100.0 parts by weight of bisphenol A type epoxy resin to 70℃, add 12.0 parts by weight of carboxyl-terminated butadiene-acrylonitrile rubber, and stir at 800 r / min for 30 minutes for pre-reaction; cool to 35℃, add 20.0 parts by weight of reactive diluent C12-C14 alkyl glycidyl ether and 3.0 parts by weight of fumed silica, and disperse at 2000 r / min for 20 minutes under vacuum of -0.098 MPa using a planetary mixer until no bubbles are present and the filler is uniformly dispersed; Preparation of Component B: Mix 45.0 parts by weight of modified alicyclic amine curing agent with 4.0 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol and 1.5 parts by weight of γ-glycidyl etheroxypropyltrimethoxysilane at room temperature and stir at low speed (300 r / min) for 10 minutes until a homogeneous system is formed; When using, mix Component A and Component B at a mass ratio of 3:1.

[0057] Preparation Example 7:

[0058] This preparation example provides a friction-type clamp liner coating, including the following steps:

[0059] A 2.0mm thick Q235 low-carbon steel plate was selected as the substrate, and a 2.0mm diameter pure aluminum wire was selected as the coating material. The coating was prepared by arc spraying, with the following process parameters: spraying voltage 28V, spraying current 180A, spraying distance 150mm, and compressed air pressure 0.5MPa. The number of spraying passes was controlled to obtain a coating thickness of 200μm, and the surface roughness Ra was measured to be 12.5μm.

[0060] Preparation Example 8:

[0061] This preparation example provides a friction-type clamp liner coating, including the following steps:

[0062] A 2.5mm thick Q235 low-carbon steel plate was selected as the substrate, and a 2.0mm diameter pure aluminum wire was selected as the coating material. The coating was prepared by arc spraying, with the following process parameters: spraying voltage 30V, spraying current 200A, spraying distance 175mm, and compressed air pressure 0.6MPa. The number of spraying passes was controlled to obtain a coating thickness of 250μm, and the surface roughness Ra was measured to be 18.0μm.

[0063] Preparation Example 9:

[0064] This preparation example provides a friction-type clamp liner coating, including the following steps:

[0065] A 3.0mm thick Q235 low-carbon steel plate was selected as the substrate, and a 2.0mm diameter pure aluminum wire was selected as the coating material. The coating was prepared by arc spraying, with the following process parameters: spraying voltage 32V, spraying current 220A, spraying distance 200mm, and compressed air pressure 0.7MPa. The number of spraying passes was controlled to obtain a coating thickness of 300μm, and the surface roughness Ra was measured to be 25.0μm.

[0066] Examples 1 to 3:

[0067] Example 1:

[0068] This embodiment provides a method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption. It is suitable for light-load conditions with gentle slopes and relatively stable environments, and includes the following steps:

[0069] S1. Construction of a slope risk source pretreatment and sensor-linked defense system:

[0070] A 55.0m vertical range on the uphill side of the tower was defined as the inspection area. Holes (38mm diameter) were drilled into the identified unstable rock masses, and the modified static fracturing agent slurry prepared in Example 1 was injected. The slurry was allowed to stand for 12 hours to complete the fracturing process. A rigid protective frame was constructed on the uphill side of the damaged tower leg. The main body was made of D50 steel pipe, 1.9m high and 5.8m wide, with the bottom embedded 30.0cm into the rock. A mechanical displacement trigger was installed on the main upright on the back side of the protective frame, with the trigger threshold set at a 45.0mm horizontal displacement of the frame. A Φ3.0mm stainless steel signal transmission cable was laid and connected to the tower base, with a pretension of 50N.

[0071] S2. Establishment of a dual rigid-flexible reinforcement system for the tower body based on lossless connection:

[0072] Friction-coated wedge-shaped clamps were installed at both ends of the damaged main material section. The inner lining of the clamps was made of aluminum-coated soft steel plate (coating thickness 200 μm, Ra 12.5 μm) prepared in Example 7. A pre-tightening torque of 180 N·m was applied to the clamps to make the wedge structure self-locking. Q420L200×24 secondary main material and rigid-flexible coupling prestressed nodes (disc spring stiffness 1.8 kN / mm) were installed between the clamp hanging points. The nodes were adjusted by a hydraulic pump to pre-apply an axial lifting force of 108.0 kN to the secondary main material. A Φ18 auxiliary steel wire rope and spring locking module were laid out. The release pin of the locking module was connected to the signal transmission cable, and the tension of the steel wire rope was adjusted to 130.0 kN to put it in a ready-to-launch state.

[0073] S3. Uninterrupted removal and load transfer of damaged components:

[0074] Fine-tune the hydraulic nodes of the secondary main material and monitor the strain of the original main material until the load is completely transferred. Maintain a safe distance of 15.5m between the workers and the live parts, remove the connecting bolts of the damaged components one by one and cut them out, controlling the change in horizontal displacement of the tower top to not exceed 3mm during the process.

[0075] S4. Installation of new components and in-situ curing and adhesive bonding:

[0076] The new main material, with a pre-fabricated 0.3mm deep microchannel mesh and injection holes on the flange face, was hoisted into place, and M24 bolts were inserted with an initial tightening torque of 100 N·m. A high-pressure injection gun was connected, and the low-viscosity epoxy structural adhesive prepared in Example 4 was injected, with the injection pressure controlled at 2.0 MPa, until adhesive overflowed from the vent hole. The pressure was maintained for 3 minutes, and after standing for 10 minutes to allow the adhesive to initially solidify, the bolts were finally tightened to a torque of 240 N·m, ensuring the adhesive layer filled the bolt gaps.

[0077] S5. Corrosion Protection and System Decoupling:

[0078] After the epoxy structural adhesive has cured for 24 hours, clean the connection area and spray with epoxy zinc-rich primer, with a dry film thickness of 75.0 μm. Complete the system disassembly in the following order: release the tension of the steel cables, release the pressure of the secondary main materials, and remove the clamps and linkage cables.

[0079] Example 2:

[0080] This embodiment provides a method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption. It is applicable to standard mountainous terrain and conventional load conditions, and includes the following steps:

[0081] S1. Construction of a slope risk source pretreatment and sensor-linked defense system:

[0082] A 60.0m vertical range on the uphill side of the tower was defined as the inspection area. Holes (40mm diameter) were drilled into the unstable rock mass, and the modified static fracturing agent slurry prepared in Example 2 was injected. After standing for 10 hours, fracturing and cleaning were completed. A D50 steel pipe protective frame with a height of 2.0m and a width of 6.0m was erected, with the bottom embedded in the rock to a depth of 33.0cm. A mechanical displacement trigger was installed, with the trigger threshold set at a horizontal displacement of 50.0mm for the frame; a Φ3.5mm signal transmission cable was laid, with a pretension set to 65N.

[0083] S2. Establishment of a dual rigid-flexible reinforcement system for the tower body based on lossless connection:

[0084] A wedge-shaped clamp with a friction-type coating is installed, and the inner lining is made of aluminum-coated soft steel plate (coating thickness 250 μm, Ra 18.0 μm) prepared in Example 8; a preload torque of 190 N·m is applied. The secondary main member and rigid-flexible coupling prestressed joint (disc spring assembly stiffness 2.0 kN / mm) are installed, and an axial lifting force of 112.0 kN is pre-applied to the secondary main member. Auxiliary wire ropes and locking modules are laid, signal transmission cables are connected, and the wire rope tension is adjusted to 135.0 kN.

[0085] S3. Uninterrupted removal and load transfer of damaged components:

[0086] From the fine adjustment point to the load transfer, maintain a safe distance of 16.0m from the energized body, remove the damaged components, and control the change in horizontal displacement of the tower top to not exceed 4mm during the process.

[0087] S4. Installation of new components and in-situ curing and adhesive bonding:

[0088] The new main material with a prefabricated microchannel mesh with a depth of 0.4 mm was hoisted, with an initial tightening torque of 110 N·m. The standard viscosity epoxy structural adhesive prepared in Example 5 was injected, with the injection pressure controlled at 2.5 MPa, until overflow. The pressure was maintained for 4 minutes, and the mixture was allowed to stand for 12 minutes for initial setting. Finally, the bolts were tightened to a torque of 250 N·m.

[0089] S5. Corrosion Protection and System Decoupling:

[0090] After curing for 24 hours, apply epoxy zinc-rich primer with a dry film thickness of 80.0 μm. Remove the temporary reinforcement facilities in sequence.

[0091] Example 3:

[0092] This embodiment provides a method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without interrupting power supply. It is applicable to steep slopes, heavy loads, and harsh environmental conditions, and includes the following steps:

[0093] S1. Construction of a slope risk source pretreatment and sensor-linked defense system:

[0094] The area within a 65.0m vertical range on the uphill side of the tower was designated as the inspection zone. Holes (42mm diameter) were drilled into the unstable rock mass, and the modified static fracturing agent slurry prepared in Example 3 was injected. After standing for 8 hours, fracturing and cleaning were completed. A reinforced protective frame with a height of 2.1m and a width of 6.2m was erected, with its bottom embedded in the rock to a depth of 35.0cm. A mechanical displacement trigger was installed, with the trigger threshold set at a 55.0mm horizontal displacement of the frame (anti-accidental trigger mode). A Φ4.0mm signal transmission cable was laid, with a pretension set to 80N.

[0095] S2. Establishment of a dual rigid-flexible reinforcement system for the tower body based on lossless connection:

[0096] Install a wedge-shaped clamp with a friction-type coating. The inner lining layer is made of aluminum-coated soft steel plate (coating thickness 300 μm, Ra 25.0 μm) prepared in Example 9. Apply a preload torque of 200 N·m to ensure maximum frictional engagement force. Install the secondary main member and the rigid-flexible coupling prestressed node (disc spring stiffness 2.2 kN / mm), and pre-apply an axial lifting force of 115.0 kN to the secondary main member. Lay out auxiliary wire ropes and locking modules, connect the signal transmission cable, and adjust the wire rope tension to 140.0 kN.

[0097] S3. Uninterrupted removal and load transfer of damaged components:

[0098] From the fine adjustment point to the load transfer, maintain a safe distance of 16.5m from the energized body, remove the damaged components, and strictly control the change in horizontal displacement of the tower top to not exceed 5mm during the process.

[0099] S4. Installation of new components and in-situ curing and adhesive bonding:

[0100] The new main material with a prefabricated microchannel mesh of 0.5 mm depth was hoisted, with an initial tightening torque of 120 N·m. The high-viscosity / thixotropic epoxy structural adhesive prepared in Example 6 was injected, with the injection pressure controlled at 3.0 MPa to ensure full filling within a large tolerance. Pressure was maintained for 5 minutes, followed by 15 minutes of initial setting. The bolts were then finally tightened to a torque of 260 N·m.

[0101] S5. Corrosion Protection and System Decoupling:

[0102] After curing for 24 hours, apply epoxy zinc-rich primer with a dry film thickness of 85.0 μm. Remove the temporary reinforcement facilities in sequence.

[0103] Comparative Examples 1 to 5:

[0104] Comparative Example 1:

[0105] Compared to Example 2, the difference lies in the following: Traditional live-line reinforcement and replacement methods are employed. Specifically: in step S1, the slope rock fracturing and linkage defense system is not constructed; in step S2, temporary reinforcement does not use non-destructive friction clamps, but instead, bolts are drilled into the original tower material as hanging points; the secondary main material support does not have rigid-flexible coupling prestressed nodes, and is directly lifted rigidly using jacks; in step S4, the new component installation does not use prefabricated microchannels or adhesive injection, but only ordinary bolt connections are used. All other aspects remain the same.

[0106] Comparative Example 2:

[0107] Compared to Example 2, the difference lies in the removal of the linkage mechanism between the slope and the tower. Specifically, in step S1, only the protective frame is erected, without installing mechanical displacement triggers and signal transmission cables; in step S2, the auxiliary steel wire rope of the tower is used only for static reinforcement and is not connected in series with the spring locking module linked to the slope. Everything else remains the same.

[0108] Comparative Example 3:

[0109] Compared to Example 2, the difference lies in the removal of the temporary support flexible buffer unit. Specifically, in step S2, the disc spring assembly in the rigid-flexible coupling prestressed node at the top of the secondary main material is removed, and a hydraulic jack is directly connected in series for pure rigid lifting support. Everything else remains the same.

[0110] Comparative Example 4:

[0111] Compared to Example 2, the difference lies in the replacement of the inner lining material and structure of the clamp. Specifically, in step S2, the inner lining of the friction clamp is replaced with a 5.0mm thick ordinary industrial rubber gasket, and the clamp body has no wedge-shaped self-locking structure on the outside, relying solely on the frictional force generated by the bolt preload for fixation. Everything else remains the same.

[0112] Comparative Example 5:

[0113] Compared to Example 2, the difference lies in the removal of the adhesive injection process for the new component connection. Specifically, in step S4, the new main material flange connection surface does not have a pre-fabricated microchannel mesh or adhesive injection holes. During installation, M24 bolts are directly inserted and tightened with a torque of 250 N·m, without injecting epoxy structural adhesive. Everything else remains the same.

[0114] Test cases 1 to 7:

[0115] Test Example 1: Rock Fracturing Efficiency and Expansion Properties Test

[0116] Experimental instructions and procedures:

[0117] The purpose of this experiment is to verify the hydration exothermic characteristics and cracking efficiency of the modified static fracturing agents obtained in Preparation Examples 1 to 3 in a confined space, and to evaluate whether they meet the working condition requirement of completing cracking within 8-12 hours in the examples.

[0118] The experimental subjects were the powder materials prepared in Preparation Example 1, Preparation Example 2, and Preparation Example 3. The control group used commercially available ordinary SCA fracturing agent.

[0119] The specific experimental steps are as follows:

[0120] Test block preparation: Plain concrete cube test blocks (500mm×500mm×500mm) with a strength grade of C40 were prepared to simulate medium-hardness rock. After curing the test blocks for 28 days, a loading hole with a diameter of 40mm and a depth of 400mm was drilled vertically in the center of the top surface.

[0121] Grouting: Under an ambient temperature of 20±2℃, the powder and water were mixed according to the water-cement ratio set in each preparation example, and mechanically stirred until a uniform slurry was formed. The slurry was then quickly poured into the test block holes up to 20mm from the hole opening.

[0122] Data monitoring:

[0123] Hydration temperature monitoring: A type K thermocouple is pre-embedded in the center of the charging hole and connected to a data acquisition instrument to record the core temperature changes during the slurry reaction process.

[0124] Crack initiation and propagation monitoring: Crack width gauges and acoustic emission sensors were attached to the concrete surface around the borehole. The time from the start of pouring to the appearance of the first visible crack (width ≥ 0.1 mm) on the surface of the test block was recorded as the crack initiation time; the maximum width of the main crack was measured and recorded 12 hours after pouring.

[0125] Repeatability control: Three test blocks were tested in parallel for each preparation example, and the arithmetic mean was taken.

[0126] Experimental data:

[0127] Table 1. Record of Test Data on the Fracturing Performance of Modified Static Fracturing Agent

[0128] Sample number Calcium oxide content (%) Initial water-cement ratio Maximum hydration temperature of slurry (°C) Crack initiation time (h) 12h main crack width (mm) Remark Preparation Example 1 75.0 0.28 68.4 7.3 4.8 Mild reaction, no nozzles Preparation Example 2 78.5 0.30 79.2 5.1 7.9 The reaction is stable and the cracks are regular. Preparation Example 3 82.0 0.32 88.7 3.6 11.4 Rapid response, fast crack propagation control group - 0.30 55.3 9.8 2.1 Expansion pressure builds up slowly

[0129] Note: - in Table 1 indicates that it is not applicable.

[0130] Experimental conclusions and analysis:

[0131] Experimental data show that the modified static fracturing agent prepared in this invention effectively cracked concrete specimens within 12 hours, with crack initiation time stably controlled within the range of 3.6 to 7.3 hours, and the width of the main crack after 12 hours was more than 3.7 times that of the control group. This confirms that by controlling the calcium oxide content and compounding the lattice stabilizer, the hydration heat release rate and volume expansion characteristics of the slurry were effectively optimized. The continuous expansion stress generated by this formula in confined spaces not only meets the requirements of silent and vibration-free working conditions for slope rockfall treatment, but also solves the problem of construction delays caused by the reaction lag or insufficient cracking efficiency of traditional fracturing agents.

[0132] Test Example 2: Dynamic Response Characteristics Test of Mechanical Linkage Defense System

[0133] Experimental instructions and procedures

[0134] This experiment aims to determine the mechanical response delay characteristics of the slope tower linkage defense system described in Example 2, and to verify whether the signal transmission cable can trigger the locking action of the temporary reinforcement system of the tower body within an effective time when the external impact causes the frame to shift.

[0135] The experimental site was selected in a flat and open area, and a 1:1 physical model system was built strictly according to the structural parameters determined in Example 2.

[0136] System Construction:

[0137] Triggering end: A rigid test bench is set up to simulate the protective frame, and an integrated mechanical displacement trigger is used. A servo hydraulic actuator is used to connect the test bench to apply a controllable horizontal step displacement to simulate the instantaneous deformation caused by falling rocks impacting the frame.

[0138] Transmission end: Lay a 60.0m long Φ3.5mm stainless steel signal transmission cable, and install PTFE guide rings every 5.0m along the line. Apply 65N axial pretension through the end adjusting bolt to eliminate cable slack.

[0139] Response end: Install spring locking module and auxiliary steel wire rope, and rigidly connect the release pin of the locking module to the end of the signal transmission cable.

[0140] Data Acquisition and Definition:

[0141] High-frequency laser displacement sensors (sampling frequency 5kHz) are placed at the trigger end platform and the response end release pin respectively, and displacement-time curves are recorded synchronously.

[0142] The trigger time is defined as the point in time when the horizontal displacement of the test bench reaches 50.0 mm (set threshold).

[0143] The response time is defined as the point in time when the locking module release pin produces axial displacement (the start of the pin pull-out action).

[0144] Calculate the system response delay time.

[0145] Test process:

[0146] Twenty consecutive trigger tests were performed. To assess adaptability to the field environment, a continuous lateral wind (wind speed 8 m / s) was introduced onto the transmission cable during tests 6 to 10; localized contact friction interference was applied to the middle section of the transmission cable during tests 11 to 15. The trigger and pin positions were reset after each test.

[0147] Experimental data:

[0148] Table 2. Test Data Recording Table for Long-Distance Mechanical Response Time of Linkage System

[0149] Serial Number Environmental interference conditions Displacement rate at the trigger end (m / s) Measured pretension (N) of the signal cable Response latency (ms) Triggering state 1 No interference 1.2 64.8 142 success 2 No interference 1.2 65.1 138 success 3 No interference 1.5 65.0 135 success 4 No interference 0.8 64.2 156 success 5 No interference 1.0 65.5 144 success 6 Lateral wind load 1.2 63.8 168 success 7 Lateral wind load 1.2 66.2 162 success 8 Lateral wind load 1.2 62.5 175 success 9 Lateral wind load 1.2 64.0 171 success 10 Lateral wind load 1.2 65.3 165 success 11 Contact friction 1.2 64.5 189 success 12 Contact friction 1.2 64.8 194 success 13 Contact friction 1.2 65.0 182 success 14 Contact friction 1.2 63.9 201 success 15 Contact friction 1.2 64.1 197 success 16 No interference (retest) 2.0 65.2 128 success 17 No interference (retest) 2.0 64.9 131 success 18 No interference (retest) 0.5 65.0 159 success 19 No interference (retest) 1.2 66.5 136 success 20 No interference (retest) 1.2 65.0 140 success

[0150] Experimental conclusions and analysis:

[0151] The average response delay of the mechanical linkage system was measured to be 160.65 ms, and it maintained a 100% trigger success rate under wind load and friction interference conditions. Physical mechanism analysis showed that the mechanical signal transmission speed of the pretensioned steel cable was faster than the propagation speed of the ground seismic waves, establishing the system's time advantage. Utilizing the principle of mechanical waveguides, this device completed the tensioning and locking of the auxiliary steel cable before the destructive vibration energy generated by falling rocks was fully coupled to the tower structure, effectively avoiding the risk of buckling instability of the tower legs in an open state due to sudden disturbances.

[0152] Test Example 3: Simulation Test of Microchannel Resin Filling Morphology and Density

[0153] Experimental instructions and procedures

[0154] This experiment aims to verify the hydrodynamic behavior and final filling quality of the microchannel injection process described in Example 2 within the concealed flange connection surface, and in particular, to assess whether the high-viscosity epoxy structural adhesive can effectively eliminate interfacial air under the set injection pressure, thereby achieving dense filling of the microchannel network and bolt holes.

[0155] To enable visual observation, the experiment used a transparent model to simulate the flange connection interface of the steel structure.

[0156] Visualization model preparation: A 1:1 scale flange model was made using high-transmittance polymethyl methacrylate (PMMA) sheet. Orthogonal grid-like microchannels were machined on the upper surface of the model using a CNC engraving machine, with a groove width of 1.5 mm, a groove depth of 0.4 mm, and a grid spacing of 20 mm.

[0157] Simulated assembly: The machined PMMA flange is overlapped with the flat plate base, and M24 high-strength bolts are inserted. An initial tightening torque of 110 N·m is applied using a torque wrench to simulate the contact state after the steel component is hoisted into place. At this time, the flange face clearance is mainly composed of microchannel space, and there is a tolerance clearance between the bolt and the hole wall.

[0158] Injection procedure: Take the epoxy structural adhesive prepared in Example 5 and add 0.1% by mass of oil-soluble Sudan Red dye to enhance contrast. Connect the injection equipment, set the outlet pressure to 2.5 MPa, and inject the adhesive through the preset injection hole until the adhesive continuously overflows from the vent hole without any air bubbles.

[0159] Data extraction:

[0160] Interface filling rate: After the adhesive has cured, a high-resolution top-view image of the flange surface is taken. The red adhesive layer area is extracted using a grayscale threshold segmentation algorithm, and its percentage of the total flange contact area is calculated.

[0161] Pore ​​penetration depth: Disassemble the bolted connection and use a vernier caliper to measure the length of the adhesive that has penetrated axially into the thread and hole wall gap along the bolt shank.

[0162] A total of 12 groups of samples were prepared for the experiment. During the gel injection process, the natural fluctuations of injection pressure and ambient temperature were recorded without human intervention.

[0163] Experimental data:

[0164] Table 3. Data Recording Table for Filling Performance Tests of Microchannel Injection System

[0165] Sample number Measured injection pressure (MPa) Laboratory ambient temperature (°C) Time taken for glue application (s) Effective fill rate of the interface (%) Axial penetration depth of bolt gap (mm) Defect Description 3-01 2.52 24.5 42 98.4 18.5 No obvious bubbles 3-02 2.48 24.2 45 99.1 21.2 No obvious bubbles 3-03 2.55 23.8 39 97.8 19.8 Edge micro-airbags 3-04 2.41 24.6 48 96.5 15.6 Local flow channels not full 3-05 2.50 24.1 43 99.5 22.1 No obvious bubbles 3-06 2.62 23.5 36 98.9 24.3 No obvious bubbles 3-07 2.45 25.2 44 97.2 17.4 Locally disconnected regions 3-08 2.51 24.8 41 99.3 20.9 No obvious bubbles 3-09 2.38 22.9 52 95.8 14.2 Flow stagnation 3-10 2.58 24.4 38 99.0 23.5 No obvious bubbles 3-11 2.49 24.0 43 98.6 19.6 No obvious bubbles 3-12 2.53 23.9 40 99.2 20.4 No obvious bubbles

[0166] Experimental conclusions and analysis:

[0167] Experiments confirmed that the microchannel injection process achieved a 98.2% interface filling rate under 2.5 MPa pressure, and allowed the adhesive to penetrate nearly 20 mm axially along the bolt gap. Fluid dynamics analysis showed that the prefabricated microchannels altered the laminar flow pattern of the adhesive, effectively eliminating interfacial air through a skeleton-priority flow mechanism. The cured epoxy resin constructed a composite connection structure of macroscopic adhesive layer bonding and microscopic pin interlocking. This structure fully filled the mechanical assembly gaps, improving the sealing performance and shear stiffness of the connection nodes between new and old components.

[0168] Test Example 4: Axial Slip Resistance Test of Temporary Reinforced Hoop System

[0169] Experimental instructions and procedures:

[0170] This experiment aims to compare and verify the anti-slip limit capability of the aluminum-sprayed wedge clamp described in Example 2 and the conventional rubber pad clamp described in Comparative Example 4 under axial load. The experiment focuses on investigating the tribological properties of the lining interface and the effect of the wedge-shaped self-locking structure on the clamp's load-bearing capacity.

[0171] The experiment was conducted on a 2000kN electro-hydraulic servo universal testing machine.

[0172] Specimen preparation: A Q345B steel pipe (Φ200mm×10mm) was cut as the main material for simulating the tower leg.

[0173] Experimental Group (Group A): The wedge-shaped clamp described in Example 2 was installed, with the inner lining being the arc-sprayed aluminum coating (Ra 18.0 μm) of Preparation Example 8. A preload torque of 190 N·m was applied to the connecting bolts using a torque wrench.

[0174] Control group (Group B): The ordinary clamp described in Comparative Example 4 was installed, with a 5.0 mm thick industrial rubber pad as the inner lining. A preload torque of 190 N·m (or up to the rubber's limit compression) was also applied.

[0175] Loading scheme: The clamp is fixed to the middle of the steel pipe, and the bottom of the steel pipe is rigidly supported. The actuating head of the testing machine presses vertically downward at a rate of 2 mm / min on the upper edge of the clamp to simulate the jacking reaction force of the sub-main material or the axial shear force transmitted by the self-weight of the tower body.

[0176] Failure criterion: When the relative displacement of the clamp along the axial direction of the steel pipe reaches 2.0 mm, it is determined that engineering slippage has occurred, and the load value at this time is recorded as the ultimate anti-slip load.

[0177] Data recording: Load displacement curves were collected throughout the process, and the surface morphology of the clamp lining after slippage was observed.

[0178] Each group underwent 8 parallel tests, and the data dispersion was recorded.

[0179] Experimental data:

[0180] Table 4. Test data of the ultimate slip resistance load of the temporary clamp system

[0181] Test number Sample type Initial preload torque (N·m) Slip critical load (kN) Load retention rate (%) at a displacement of 2 mm Damage mode observation 4-01 Group A 190.2 145.6 98.5 The coating has slight scratches and no peeling. 4-02 Group A 189.8 152.3 99.1 Partial embedding of coating 4-03 Group A 190.5 148.9 98.8 Minor scratches on the coating 4-04 Group A 188.5 139.5 96.4 The wedge block is clearly pressed down to lock. 4-05 Group A 191.0 155.8 99.4 The coating is deeply embedded 4-06 Group A 190.0 147.2 97.9 Normal wear and tear 4-07 Group A 189.5 150.1 98.2 Normal wear and tear 4-08 Group A 190.3 143.7 97.5 Normal wear and tear 4-09 Group B 190.1 38.5 65.2 Rubber shear tearing 4-10 Group B 190.4 42.1 68.4 Rubber large deformation slip 4-11 Group B 189.9 35.6 58.9 Overall sliding 4-12 Group B 190.0 39.8 64.1 Rubber extrusion failure 4-13 Group B 190.2 40.5 66.7 Overall sliding 4-14 Group B 189.6 37.2 61.3 Rubber shear deformation 4-15 Group B 190.5 41.3 67.8 Overall sliding 4-16 Group B 189.7 36.9 60.5 Rubber wear failure

[0182] Experimental conclusions and analysis:

[0183] The average anti-slip limit load measured by the aluminum-coated wedge clamp system is 147.9 kN, approximately 3.8 times that of traditional rubber pad clamps, and the load retention rate after loading exceeds 98%. This performance stems from the micro-mechanical interlocking effect formed between the aluminum coating and the steel substrate, transforming the contact mechanism into a composite friction of adhesion and furrowing. Simultaneously, the self-locking mechanism of the wedge structure converts axial shear force into radial clamping force, creating a positive feedback mechanical characteristic where the greater the load, the tighter the clamping, fundamentally solving the slippage failure problem of temporary support systems under heavy loads.

[0184] Test Example 5: Dynamic Stability and Load Transfer Characteristics Test of Rigid-Flexible Coupled Support System

[0185] Experimental instructions and procedures:

[0186] This experiment aims to verify the load-holding capacity and structural stability of the rigid-flexible coupled prestressed node used in Example 2 under simulated dynamic wind load disturbance, and to compare it with the purely rigid jacking support described in Comparative Example 3. The core of the experiment is to examine whether the temporary support system can maintain a constant support force when the tower undergoes slight elastic deformation, thus avoiding stress abrupt changes caused by stiffness mismatch.

[0187] The experiment was conducted on the reaction wall and loading platform in the structural mechanics laboratory.

[0188] Model building:

[0189] Construct a 1:1 scale Q420 steel single-leg model, 3.5m high. Install the secondary main material next to the section of the main material to be replaced.

[0190] Experimental Group (Group A): The disc spring assembly node described in Example 2 is connected in series at the top of the secondary main material (stiffness set at 2.0kN / mm), and an initial support force of 112.0kN (simulating alternative load) is applied by hydraulic adjustment.

[0191] Control group (Group B): Ordinary steel pads are connected in series at the top of the secondary main material. Only a hydraulic jack is used to apply an initial support force of 112.0kN. After locking the oil circuit, a rigid support is formed.

[0192] Loading conditions:

[0193] Static load transfer: Monitor the stress release rate of the original main material under the initial state, with a target of 100%.

[0194] Dynamic disturbance simulation: A horizontal cyclic load with a frequency of 1.5 Hz and an amplitude of ±2.0 kN was applied to the top of the model using a transverse vibrator to simulate the micro-motion disturbance caused by mountain gusts on the tower legs. The load was applied continuously for 300 seconds.

[0195] Data collection:

[0196] Full-bridge strain gauges were attached to the middle of the secondary main structure to record real-time changes in the support axial force at a sampling rate of 50Hz. The maximum fluctuation amplitude and standard deviation of the support force were extracted as a key focus. Simultaneously, laser displacement gauges were used to monitor the vertical relative displacement of the nodes.

[0197] Each set of operating conditions was tested six times, including simulations of different initial installation deviations.

[0198] Experimental data

[0199] Table 5. Comparison of Dynamic Response Data between Rigid-Flexible Coupling and Rigid Support Systems

[0200] Test number Sample type Initial support force setting (kN) Force fluctuation amplitude (kN) under dynamic disturbance Load standard deviation (kN) Maximum vertical displacement of the node (mm) State determination 5-01 Group A 112.1 3.4 0.85 1.65 Stablize 5-02 Group A 111.8 4.1 1.02 1.92 Stablize 5-03 Group A 112.5 2.9 0.74 1.48 Stablize 5-04 Group B 112.2 28.6 8.45 0.32 Load mutation 5-05 Group B 111.9 32.1 9.12 0.28 Load mutation 5-06 Group A 112.0 3.8 0.96 1.74 Stablize 5-07 Group A 112.3 3.2 0.81 1.55 Stablize 5-08 Group B 112.4 25.8 7.88 0.35 Load mutation 5-09 Group B 111.7 35.4 10.25 0.24 Extremely unstable 5-10 Group A 111.5 4.5 1.15 2.05 Stablize 5-11 Group B 112.6 29.7 8.66 0.30 Load mutation 5-12 Group B 112.0 31.2 9.04 0.29 Load mutation

[0201] Note: In the sample types, Group A is from Example 2 and Group B is from Comparative Example 3.

[0202] Experimental conclusions and analysis:

[0203] Under dynamic wind load disturbance, the rigid-flexible coupling support system controls the fluctuation range of the support force to within 3.2% of the initial load, while the fluctuation range of the purely rigid support system is as high as 27.2%. Data shows that the nonlinear elastic buffer introduced by the disc spring assembly effectively solves the stiffness mismatch problem. This structure utilizes the constant force spring effect to absorb and dissipate external displacement energy, ensuring that even when the tower undergoes micro-deformation, the secondary main material can still provide a constant and continuous support reaction force, avoiding instantaneous unloading or overload impact caused by rigid contact.

[0204] Test Example 6: Fatigue Resistance and Stiffness Degradation Test of Connection Nodes

[0205] Experimental instructions and procedures:

[0206] This experiment aims to evaluate the structural durability of the microchannel injection-bonded bolt connection described in Example 2 under high-cycle fatigue loads, particularly to examine the effects of this composite connection method on suppressing nodal slip, delaying stiffness degradation, and improving fatigue life. The ordinary bolt connection described in Comparative Example 5 is used as a comparison.

[0207] The experimental equipment used was the MTS370.50 electro-hydraulic servo fatigue testing machine.

[0208] Specimen design and preparation:

[0209] The test unit is designed with a double shear lap joint. Both the main board and the cover plate are made of Q420 steel, with a Φ26mm hole in the middle, and are connected with M24 high-strength bolts.

[0210] Experimental group (Group A): Following the process in Example 2, microchannels were prefabricated on the bonding surface of the board, and after assembly, an initial tightening torque was applied, epoxy structural adhesive was injected and cured, and finally tightened to 250 N·m.

[0211] Control group (Group B): The assembly was carried out directly according to the process of Comparative Example 5 and finally screwed to 250 N·m without glue injection.

[0212] Fatigue loading scheme:

[0213] Sine wave loading was used with a stress ratio of R=0.1 (tension-tension cycle) and a loading frequency of 8Hz. The maximum fatigue load was set to 160kN (approximately 65% ​​of the main material's design yield strength, sufficient to induce fretting slip in a conventional connection).

[0214] Termination conditions:

[0215] The test is stopped when the specimen breaks, or the displacement amplitude increases by 2.0 mm from the initial value (determined as loosening failure), or the number of cycles reaches 2,000,000 (considered as infinite life).

[0216] Monitoring indicators:

[0217] The load-displacement hysteresis curve was recorded in real time using an extensometer. The nodal secant stiffness was extracted for a specific number of cycles (N=1,1000,10000,100000,500000...), and the final failure life and failure mode were recorded.

[0218] Each test group consists of 10 specimens to capture the dispersion of fatigue data.

[0219] Experimental data:

[0220] Table 6. Record of Test Data on Fatigue Life and Residual Stiffness of Nodals

[0221] Sample number Group Initial stiffness (kN / mm) Stiffness retention rate (%) after 500,000 cycles Fatigue life Final Destruction Mode 6-01 Group A 215.4 98.2 ＞2,000,000 Not expired (stopped) 6-02 Group A 218.1 97.5 ＞2,000,000 Not expired (stopped) 6-03 Group A 214.8 96.8 1,854,200 Bolt root fracture 6-04 Group A 216.5 98.1 ＞2,000,000 Not expired (stopped) 6-05 Group A 212.9 97.3 1,923,500 Cracking at the edge of the hole in the board 6-06 Group A 217.0 97.9 ＞2,000,000 Not expired (stopped) 6-07 Group B 208.5 65.4 542,100 Loose bolts sheared 6-08 Group B 210.2 72.1 688,400 Loose bolts sheared 6-09 Group B 198.6 58.2 421,500 Plate hole wall crushing 6-10 Group B 205.4 68.9 615,200 Loose bolts sheared 6-11 Group B 202.1 61.5 489,300 Loose bolts sheared 6-12 Group A 213.5 96.2 1,789,000 The adhesive layer broke after detachment. 6-13 Group B 209.8 70.3 654,100 Loose bolts sheared 6-14 Group B 201.5 63.8 501,200 Plate hole wall crushing

[0222] Experimental conclusions and analysis:

[0223] The microchannel glue-injected joint did not fail after 2 million high-cycle fatigue cycles, maintaining a stiffness retention rate of over 97%, far superior to the approximately 560,000-cycle fatigue life of ordinary bolted connections. The mechanism lies in the fact that the cured adhesive layer completely fills the bolt holes and microchannels, forming a high-strength mechanical key. This restricts the initial relative displacement between the plate and bolts, eliminating the motion conditions that lead to fretting wear, allowing the joint to maintain a quasi-rigid state throughout its entire lifespan and delaying structural stiffness degradation.

[0224] Test Example 7: Verification of the operating system's stability under full-condition shock and its active defense effectiveness

[0225] Experimental instructions and procedures:

[0226] This experiment aims to verify the system-level response capability of the inductive linkage defense system constructed in Example 2 under real rockfall impact conditions. The focus is on assessing whether, under the most unfavorable condition of main material removal and load temporarily borne by secondary main materials, the system can effectively suppress transient displacement of the tower leg structure and prevent structural instability caused by kinetic energy transfer when an external impact occurs.

[0227] The experiment was conducted at a large-scale structural impact dynamics test site.

[0228] Model building:

[0229] Establish a 1:1 full-size single tower leg node model, including the tower leg plate, main material nodes, and connecting diagonal members.

[0230] Operating conditions: The middle section of the main structure is removed, and the rigid-flexible coupling secondary main structure and auxiliary steel wire rope described in Example 2 are installed. An axial load of 112kN is applied through the hydraulic system to simulate the self-weight of the upper tower.

[0231] Defense system connection: A protective frame is set up 3.0m uphill on the model.

[0232] Experimental Group (Group A): Connect the mechanical displacement trigger to the signal transmission cable, and the auxiliary steel wire rope series spring locking module (in standby state).

[0233] Control group (Group B): Only protective frames and auxiliary steel wire ropes (static tension) were installed, without mechanical linkage triggering mechanism (simulation comparison example 2).

[0234] Impact loading:

[0235] A pendulum impact testing machine with a pendulum mass of 500 kg was used. The height of the pendulum was adjusted to apply lateral horizontal impacts of different energy levels (2kJ, 5kJ, 8kJ, 10kJ) to the protective frame to simulate falling rocks hitting the frame.

[0236] Data collection:

[0237] The maximum horizontal transient displacement at the top of the tower leg node was monitored using a non-contact three-dimensional dynamic capture system (sampling rate 1000Hz).

[0238] Strain patterns were attached to key sections of the secondary main material and the remaining diagonal material to record the peak stress changes during the impact process.

[0239] Record the operating status of the auxiliary wire rope locking module and the tension changes after locking.

[0240] Three tests were conducted for each impact energy level, and the structural integrity was checked and the structure was reset after each test.

[0241] Experimental data:

[0242] Table 7. System Impact Response and Structural Stability Test Data Recording Table

[0243] Sample number Group Impact energy (kJ) Defense mechanism status Maximum horizontal displacement of tower leg joint (mm) Peak stress (MPa) of critical oblique material Auxiliary cable tension increment (kN) Structural state determination 7-01 Group A 2.1 Trigger Lock 1.2 45.3 +12.5 Stablize 7-02 Group B 2.0 No action 3.8 62.1 +1.2 The shaking was obvious. 7-03 Group A 4.9 Trigger Lock 2.4 58.7 +21.8 Stablize 7-04 Group B 5.1 No action 8.6 115.4 +2.5 violent shaking 7-05 Group A 8.2 Trigger Lock 3.9 72.5 +34.1 Stablize 7-06 Group B 7.9 No action 15.2 189.6 +4.1 Local yield risk 7-07 Group A 10.1 Trigger Lock 5.1 84.2 +42.6 Stablize 7-08 Group B 10.0 No action 21.4 245.8 +5.3 Structural instability and failure 7-09 Group A 5.0 Trigger Lock 2.6 60.1 +20.9 Stablize 7-10 Group B 4.9 No action 9.1 118.2 +2.8 violent shaking 7-11 Group A 8.0 Trigger Lock 4.2 75.8 +33.5 Stablize 7-12 Group B 8.1 No action 14.8 182.3 +3.9 Local yield risk

[0244] Experimental conclusions and analysis:

[0245] The coordinated defense system limited the maximum displacement of the tower leg to 5.1 mm under a 10 kJ high-energy impact, effectively preventing structural instability and damage (displacement up to 21.4 mm) that would have occurred without defense. By instantaneously tensioning the auxiliary cables, the system introduced new high-stiffness constraint points into the structure within milliseconds, actively reconstructing the boundary conditions. This mechanism converted the overturning energy originally acting on the damaged tower leg into cable axial force and transmitted it to the anchorage end, successfully preventing the accumulation of impact energy towards weak points in the structure and ensuring the overall safety of the operating system.

Claims

1. A method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, characterized in that, Includes the following steps: S1. Drill holes on the upslope side of the tower to inject modified static rock fracturing agent to remove the unstable rock mass in advance, and establish a rigid protective frame; install mechanical displacement triggers on the rigid protective frame, and extend signal transmission cables to the damaged tower leg, thereby constructing an induction linkage defense system around the work area. S2. Under the protection of the inductive linkage defense system constructed in step S1, wedge-shaped clamps with friction-type coatings are installed at the nodes at both ends of the damaged main material section, and secondary main materials and rigid-flexible coupling prestressed nodes are installed in parallel between the hanging points of the wedge-shaped clamps; the signal transmission cable is connected to the spring locking module connected in series on the auxiliary steel wire rope, and the tension of the auxiliary steel wire rope is adjusted to make the tension of the steel wire rope in a defense state ready to be triggered, thus completing the establishment of the reinforcement system; S3. Adjust the rigid-flexible coupling prestressed node to transfer the load borne by the damaged main material to the secondary main material; After the load transfer is completed, the damaged main material is removed to create an installation space; S4. Hoist the new main material with pre-fabricated microchannel mesh and injection holes on the flange face in the installation space, and apply the initial tightening torque; use microchannel injection to inject in-situ curing microchannel injection special epoxy structural adhesive, let it stand under pressure until the adhesive initially sets, and then tighten the bolts to achieve a gapless connection between the new main material and the original tower body. S5. After the injected in-situ curing microchannel epoxy structural adhesive has fully cured and reached the design strength, perform anti-corrosion treatment on the connection area; finally, complete the system disassembly in the order of first releasing the load of the auxiliary steel wire rope and the secondary main material, and then removing the clamps and linkage defense facilities.

2. The method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, is characterized in that... The modified static fracturing agent for rock fracturing is made by mixing component A, component B and water, with the mass ratio of water to the total mass of components A and B being 28%-32%. The chemical composition of component A, by mass percentage, includes: calcium oxide 75.0%-82.0%, silicon dioxide 6.0%-9.0%, aluminum oxide 2.0%-4.0%, anhydrous gypsum 9.0%-11.5%, and sodium fluorosilicate 0.5%-1.0%. Component B includes a polycarboxylate superplasticizer and an anhydrous citric acid retarder. The mass of the polycarboxylate superplasticizer is 0.8%-1.2% of the total mass of component A, and the mass of the anhydrous citric acid retarder is 0.15%-0.25% of the total mass of component A.

3. The method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 2, is characterized in that... The preparation method of component A of the modified static fracturing agent for rock fracturing is as follows: limestone, clay, and gypsum are mixed in stoichiometric ratio and calcined at 1400℃-1450℃ for 2.0-2.5 hours to obtain clinker; after cooling, the clinker is mixed with sodium fluorosilicate and ground until the specific surface area is 350-400 m². 2 / kg.

4. The method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, is characterized in that... The trigger threshold of the mechanical displacement trigger is set to a horizontal displacement of 45.0mm-55.0mm for the rigid protective frame; the pretension of the signal transmission cable is set to 50N-80N.

5. The method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, is characterized in that... The friction coating is prepared by arc spraying process, using Q235 low carbon steel plate as substrate and pure aluminum wire as spraying material. The parameters of the arc spraying process are controlled as follows: spraying voltage 28V-32V, spraying current 180A-220A, spraying distance 150mm-200mm, and compressed air pressure 0.5MPa-0.7MPa; the resulting coating thickness is 200μm-300μm, and the surface roughness Ra is 12.5μm-25.0μm.

6. The method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, is characterized in that... The stiffness of the disc spring assembly in the rigid-flexible coupling prestressed node is 1.8kN / mm-2.2kN / mm; the axial lifting force of the secondary main material is 108.0kN-115.0kN; and the tension of the auxiliary wire rope is adjusted to 130.0kN-140.0kN.

7. The method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, is characterized in that... The in-situ curing microchannel injection-specific epoxy structural adhesive is composed of component A and component B mixed in a mass ratio of 2:1-3:

1. The first component is made from raw materials comprising the following parts by weight: 100.0 parts of bisphenol A type epoxy resin, 8.0-12.0 parts of carboxyl-terminated butadiene-acrylonitrile rubber, 15.0-20.0 parts of reactive diluent C12-C14 alkyl glycidyl ether, and 2.0-3.0 parts of fumed silica. Component B is made from raw materials comprising the following parts by weight: 35.0-45.0 parts of modified alicyclic amine curing agent, 2.0-4.0 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 1.0-1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane.

8. A method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 7, is characterized in that... The preparation method of the in-situ curing microchannel injection-specific epoxy structural adhesive includes: Preparation of component A: The bisphenol A type epoxy resin and the carboxyl-terminated butadiene nitrile rubber are stirred and pre-reacted at 60℃-70℃ for 30-40 minutes. After cooling, the reactive diluent and the fumed silica are added. The mixture is dispersed at 1500r / min-2000r / min for 20-30 minutes under a vacuum of -0.095MPa to -0.098MPa. Preparation of component B: The modified alicyclic amine curing agent, the 2,4,6-tris(dimethylaminomethyl)phenol and the γ-glycidoxypropyltrimethoxysilane are stirred at low speed at room temperature for 10-15 minutes until a homogeneous system is formed.

9. A method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, is characterized in that... The depth of the microchannel mesh is 0.3mm-0.5mm; the injection pressure is controlled at 2.0MPa-3.0MPa; and the final tightening torque is 240N·m-260N·m.

10. A method for replacing main components of power transmission towers damaged by rockfalls in mountainous areas without power interruption, as described in claim 1, characterized in that, In step S3, the change in horizontal displacement of the tower top is controlled to not exceed 3mm-5mm; in step S5, the surface anti-corrosion treatment is to spray an epoxy zinc-rich primer with a dry film thickness of 75.0μm-85.0μm.