Combined supporting method and device

Abstract

The invention provides a combined supporting method and device, and relates to the technical field of mine roadway supporting. The method comprises the following steps: knocking a wall top, and cleaning pumice stones and dangerous stones on the surface of roadway surrounding rock; anchor rods are installed around the roadway, and first preset pre-tightening force is applied to the anchor rods; forming a wet-sprayed concrete layer around the roadway by spraying wet-sprayed concrete, and covering the tail end of the anchor rod with the wet-sprayed concrete layer; anchor cables are installed, and second preset pre-tightening force is applied, so that a shell structure composed of the anchor rods and the concrete layer is anchored in a deep stable rock stratum; and a reaction type thin spraying material is sprayed on the surface of the wet spraying concrete layer through a composite spraying layer technology, and a reaction type thin spraying material layer with the elastomer protection performance is formed on the outer side of the wet spraying concrete layer and the outer side of the anchor cable. By covering the reaction type thin spraying material layer, the characteristics of rigid supporting and flexible supporting are considered, the problems that the brittle geological disaster risk is high, a metal net is prone to corrosion, the effective utilization rate is low, and the net hanging efficiency is low are solved, and the stability of surrounding rock can also be enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of mine tunnel support, in particular to a combined support method and device. Background Art

[0002] Anchor mesh spraying support mainly consists of three parts: anchor rod, steel mesh (or fiber mesh) and sprayed concrete (mortar). As an important support method, anchor mesh spraying support is widely used in mining projects, tunnel projects, water conservancy and hydropower projects, etc. It is of great significance to maintain the stability of rock mass in large-section chambers, high-stress surrounding rocks and other areas.

[0003] However, for soft rock area support, the tunnel surrounding rock is loose and broken, prone to large deformation. Metal mesh has disadvantages such as low installation efficiency and high construction cost, which leads to untimely sealing of the shotcrete surface and further weathering and softening of the surrounding rock. At the same time, as a brittle material, the concrete spraying layer cannot withstand large deformation and is prone to brittle failure, making geological disasters sudden. Therefore, traditional support methods are difficult to effectively control surrounding rock deformation in soft rock tunnels, and more flexible or composite support technologies are urgently needed to deal with the large deformation problem of soft rock tunnels. Summary of the invention

[0004] In order to solve the technical problems that the existing technology of soft rock area support, the tunnel surrounding rock is loose and broken, prone to large deformation, and the sprayed concrete is prone to cracking due to the shortcomings of low metal mesh installation efficiency, high construction cost, and brittle concrete materials that cannot withstand large deformation, and the soft rock tunnel support effect is poor, the embodiment of the present invention provides a combined support method and device. The technical solution is as follows:

[0005] In one aspect, a combined support method is provided, the method comprising:

[0006] Step 1: Knock on the top and clean up the floating stones and dangerous rocks on the surface of the tunnel surrounding rock;

[0007] Step 2: installing anchor rods around the tunnel and applying a first preset preload force to the anchor rods;

[0008] Step 3: Form a wet shotcrete layer around the tunnel by spraying wet shotcrete, and make the wet shotcrete layer cover the tail end of the anchor bolt;

[0009] Step 4: Install the anchor cable and apply a second preset preload force to anchor the shell structure consisting of the anchor rod and the concrete layer in the deep stable rock formation;

[0010] Step 5: Use a composite spraying process to spray the reactive thin-spray material on the surface of the wet-sprayed concrete layer, and form a reactive thin-spray material layer with elastomeric protective properties on the wet-sprayed concrete layer and the outside of the anchor cable.

[0011] Optionally, the reactive thin-spray material layer is formed by using a two-component elastomer nano-modified material, which is processed by a thin-spray machine under heating and pressure, mixed evenly, and then sprayed and cured.

[0012] Optionally, the elastomer nano-modified material includes component A and component B, and the component A and the component B are mixed and reacted at a spray outlet.

[0013] Optionally, the component A is a semi-prepolymer: the semi-prepolymer is prepared by using isocyanate, polyether diol, a second diluent and self-repairing microcapsules as raw materials, and mixing the raw materials and reacting them in an inert gas to obtain:

[0014] The B component includes amino-terminated polyether, composite metal phase change microcapsule emulsion, amine chain extender and metal powder. The preparation method of the self-repairing microcapsule includes:

[0015] S1, ① prepare reaction pre-emulsion M:

[0016] The initiator, the emulsifier and the water are mixed, and the pH value of the obtained solution is adjusted to 3-4 after emulsification to obtain a reaction pre-emulsion M: the emulsifier is one or more of an anionic surfactant and a nonionic surfactant; the initiator is benzoyl peroxide or azobisisobutyronitrile;

[0017] The mass ratio of the emulsifier to water is 1.5-4:60;

[0018] ②Preparing a reaction pre-emulsion N: dispersing and emulsifying a first diluent, an alkyd resin and an aqueous solution of methyl methacrylate to obtain a reaction pre-emulsion N; wherein the first diluent is one or more of di-n-octyl phthalate, dibutyl benzyl phthalate, ethyl carbonate and propyl carbonate;

[0019] The mass ratio of the first diluent to the alkyd resin is no more than 1:1.2;

[0020] S2, mixing the reaction pre-emulsion M and the reaction pre-emulsion N uniformly, heating to 60-80° C., and keeping the temperature for 3-5 hours to obtain a reaction emulsion;

[0021] S3, washing and drying the reaction emulsion to obtain self-repairing microcapsules;

[0022] The second diluent is one or more of di-n-octyl phthalate, dibutyl benzyl phthalate, ethyl carbonate and propyl carbonate.

[0023] Optionally, the mixing ratio of component A to component B is 1:1.

[0024] Optionally, the mass fractions of the components in the raw materials are: 40-60 parts of isocyanate, 40-50 parts of polyether diol, 1-10 parts of self-healing microcapsules and 1-10 parts of the second diluent;

[0025] The mass proportions of the components in the B component are: 40-60 parts of amino-terminated polyether, 30-50 parts of amine chain extender, 1-20 parts of composite metal microcapsule emulsion and 1-5 parts of metal powder.

[0026] Optionally, the thickness of the wet sprayed concrete layer is 100 mm, and the surface roughness of the wet sprayed concrete layer does not exceed a preset threshold;

[0027] The thickness of the reactive thin spray material layer is 3 mm.

[0028] Optionally, the wet sprayed concrete layer has a strength grade of C20, a water-cement ratio of 0.65, a cement-sand ratio of 0.37, and a water reducer of 0.3% of the mass of the cementitious material.

[0029] The present invention also provides a combined support device, the device comprising:

[0030] A prestressed anchor rod, wherein the prestressed anchor rod is installed in the loose surrounding rock outside the tunnel, and the anchor head of the prestressed anchor rod is anchored on the surrounding rock inside the tunnel;

[0031] A wet shotcrete layer, wherein the wet shotcrete layer covers the surrounding rock inside the tunnel and covers the anchor head to form a shell structure;

[0032] A prestressed anchor cable, wherein the prestressed anchor cable is installed in the shell structure, the loose surrounding rock, and the stable surrounding rock outside the loose surrounding rock, and the anchoring end of the prestressed anchor cable is anchored on the shell structure;

[0033] A reactive thin spray material layer is bonded to the shell structure and the anchoring end, and the reactive thin spray material layer is formed by a composite spraying process.

[0034] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0035] The combined support method provided by the embodiment of the present invention can provide initial tension force to enhance the stability of the surrounding rock, reduce the deformation of the rock mass around the tunnel, and control the loosening and collapse of fragments by installing prestressed anchor rods in the loose surrounding rock outside the tunnel, and installing prestressed anchor cables in the shell structure, loose surrounding rock, and stable surrounding rock outside the loose surrounding rock. By covering the wet sprayed concrete layer with a reactive thin spray material layer, the two are consolidated, taking into account the characteristics of rigid support and flexible support, and having a good support effect on soft rock large deformation tunnels; this support method replaces the traditional anchor net spraying support method, avoiding the high risk of brittle geological disasters, easy corrosion of metal nets, low effective utilization rate, low net hanging efficiency, etc., can improve the construction environment, and has excellent green environmental protection characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 is a flow chart of a combined support method provided by an embodiment of the present invention;

[0038] Figure 2 is a cross-sectional view of a combined support device and a tunnel provided in an embodiment of the present invention;

[0039] Figure 3 It is a spacing diagram between anchor rods and anchor cables in a combined support method provided by an embodiment of the present invention;

[0040] Figure 4 is a support cross-sectional diagram of a combined support method provided by an embodiment of the present invention;

[0041] Figure 5 It is a force diagram of various support forms of a combined support method provided in an embodiment of the present invention.

[0042] Reference numerals:

[0043] 1. Prestressed anchor rod; 2. Prestressed anchor cable; 3. Wet sprayed concrete layer; 4. Reactive thin sprayed material layer. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0045] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0046] In the embodiments of the present invention, sometimes a subscript such as W1 may be mistakenly written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are consistent.

[0047] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0048] The embodiment of the present invention provides a combined support method, see Figures 1 to 5 , the method comprising:

[0049] 101: Knock on the sides and top, and clean up the loose stones and dangerous rocks on the surface of the tunnel surrounding rock.

[0050] In step 10, the surface of the surrounding rock of the tunnel is knocked to check whether there are floating stones or dangerous rocks, so as to prevent them from falling off suddenly and injuring people during the construction process. Specifically, appropriate tools (such as hammers, chisels, etc.) can be used to knock on the surface of the surrounding rock, listen to the sound to judge the stability of the rock, and clean up unstable rock fragments in time.

[0051] 102: Anchor rods are installed around the tunnel and a first preset preload force is applied to the anchor rods.

[0052] The anchor rods are used to fix the surrounding rock of the tunnel to prevent it from being deformed too much due to stress release. Specifically, holes can be drilled at certain intervals and angles around the tunnel, anchor rods can be installed, and the first preset preload can be applied using anchor rod tensioning equipment (see Figure 5 F1 in Figure 5 The length of the arrow in the figure indicates the magnitude of the force), so that the anchor rod is tightly combined with the surrounding rock.

[0053] 103: By spraying wet shotcrete, a wet shotcrete layer is formed around the tunnel, and the wet shotcrete layer covers the tail end of the anchor rod.

[0054] The wet shotcrete layer is used to provide additional support and cover the end of the anchor to protect the anchor from corrosion. Specifically, a wet shotcrete machine can be used to spray the pre-mixed concrete material around the tunnel to form a wet shotcrete layer of a certain thickness. Ensure that the concrete layer covers all the ends of the anchors and reaches the thickness and strength required by the design.

[0055] See also Figure 5 , Figure 5 F2 in the figure represents the squeezing force of the roadway side deformation on the concrete spraying layer, and its limit value is related to the compressive performance of the concrete spraying layer; F3 represents the material tension caused by the deformation of the concrete spraying layer, and its limit value is related to the tensile performance of the concrete spraying layer. As can be seen from the figure, the concrete is under compression but not tension.

[0056] 104: Install the anchor cable and apply a second preset preload force to anchor the shell structure consisting of the anchor rod and the concrete layer in the deep stable rock formation.

[0057] Cable anchors are used to further enhance the stability of the tunnel surrounding rock, especially in soft rock conditions with large deformation. Specifically, holes can be drilled in the tunnel according to the design requirements, cable anchors can be installed, and a second preset preload can be applied using tensioning equipment (see Figure 5 F4 in the figure). The anchor cable connects the tunnel surrounding rock with the deep rock through the anchor section that penetrates deep into the rock layer to form an integral support structure.

[0058] 105: The reactive thin spray material is sprayed on the surface of the wet spray concrete layer by using a composite spraying process, so as to form a reactive thin spray material layer with elastomeric protective properties on the wet spray concrete layer and the outer side of the anchor cable.

[0059] See also Figure 5 , F5 represents the extrusion pressure of the reaction type thin sprayed layer caused by the deformation of the concrete sprayed layer, and its limit value is related to the compressive performance of the reaction type thin sprayed layer; F6 represents the material tension caused by the deformation of the reaction type thin sprayed layer, and its limit value is related to the tensile performance of the reaction type thin sprayed layer.

[0060] The reactive thin-sprayed material layer is subjected to tension but not compression, and the supporting effects of the concrete sprayed layer and the thin-sprayed layer compensate each other. The combined support thus formed can replace the anchor mesh spraying to achieve a combined support effect.

[0061] Among them, the reactive thin spraying material layer is formed by a composite spraying process. Specifically, the reactive thin spraying material layer contains multiple material components and is formed by a composite spraying process. These components will undergo a chemical reaction after mixing, thereby enhancing the strength and adhesion of the material. The reactive thin spraying material layer can provide additional support strength and ensure a tight bond between all support components.

[0062] Composite spraying technology refers to the process of spraying two or more materials of different properties evenly on the surface of the substrate through a specific spraying technology, such as spray guns, spray machines and other equipment, to form one or more layers of coatings with excellent properties. These coatings may have multiple functions such as anti-corrosion, wear resistance, high temperature resistance, oxidation resistance, heat insulation, and insulation to meet the needs of different fields and occasions.

[0063] The materials used in the composite spraying process usually include resin, reinforcing materials (such as glass fiber, carbon fiber, etc.), functional fillers (such as ceramic powder, metal powder, etc.) and solvents. The selection and proportion of these materials will directly affect the performance and quality of the coating. The equipment required for the composite spraying process mainly includes sprayers, spray guns, stirrers, drying equipment, etc. The performance and accuracy of these equipment will directly affect key indicators such as uniformity, thickness and adhesion of the coating.

[0064] Use a sprayer or spray gun to evenly spray the composite material on the surface of the substrate to form one or more layers of coating. During the spraying process, it is necessary to control parameters such as spraying speed, spraying distance and spraying angle to ensure the uniformity and thickness of the coating. The sprayed coating is cured to improve its strength and durability. The curing method may include natural drying, heating curing, etc.

[0065] The composite spraying process can significantly improve the various properties of the product, such as corrosion resistance, wear resistance, high temperature resistance, etc. By optimizing the material ratio and spraying process, the production cost and energy consumption can be reduced. The composite spraying process is efficient and automated, which can greatly improve production efficiency.

[0066] Reactive thin-spraying materials are used to form a layer of reactive thin-spraying materials with elastic protective properties on the surface of the wet-sprayed concrete layer, thereby improving the impact resistance and durability of the roadway. Specifically, the reactive thin-spraying materials can be evenly sprayed onto the surface of the wet-sprayed concrete layer using spraying equipment. After spraying, this material will react and solidify quickly to form an elastic protective layer covering the outside of the concrete and anchor cables.

[0067] In this embodiment, the prestressed anchor rods and prestressed anchor cables in step 102 and step 104 have the characteristics of applying pre-tightening force, the wet sprayed concrete layer in step 103 uses traditional sprayed concrete materials, and the reactive thin sprayed material layer in step 105 uses elastomer nano-modified materials. The loose and broken area surrounding rock is anchored by the pre-tightening force of the anchor rod to control the loosening and collapse of the broken blocks.

[0068] In a specific embodiment, the diameter Φ of the prestressed anchor rod is 20 mm, the length L is 1800 mm, and the spacing between rows is 800 mm×800 mm.

[0069] The wet shotcrete layer is constructed by a wet shotcrete machine: according to the material ratio of water-cement ratio of 0.65, cement-sand ratio of 0.37, and water-reducing agent of 0.3% of the mass of cementitious materials, the raw materials are fed into the wet shotcrete machine and mixed evenly, and the concrete material is sprayed out by the wet shotcrete machine to form a wet shotcrete layer with a strength grade of C20 and a thickness of 100 mm on the surface of the tunnel surrounding rock; because the wet shotcrete layer has a certain spraying layer thickness, it can smooth the unevenness of the tunnel surrounding rock surface, thereby avoiding stress concentration; at the same time, after the wet shotcrete layer and the prestressed anchor rods form a solid shell together, they can provide high flexural strength for the tunnel and effectively bear the pressure of the tunnel surrounding rock.

[0070] Through the suspension effect of the prestressed anchor cable, the shell structure composed of the anchor rod and the concrete layer is anchored in the deep stable rock layer, so that the surrounding rock in the loose area and the deep stable surrounding rock become one, further improving the stability of the tunnel surrounding rock; the diameter of the prestressed anchor cable Φ is 21.8 mm, the length L is 6300 mm, and the spacing between rows is 1600 mm×1600 mm.

[0071] The reactive thin-sprayed material layer is operated with a thin-spraying machine: the components A and B of the elastomer nano-modified material are mixed in a 1:1 mass ratio and evenly sprayed through the thin-spraying machine. After mixing and atomization reaction, a reactive thin-sprayed material layer with a thickness of 3 mm is formed on the surface of the wet-sprayed concrete layer; by spraying the reactive thin-sprayed material, an integral support structure of anchor-spray-anchor-spray is formed.

[0072] In addition, the reactive thin-sprayed material layer has good toughness and tensile properties, which can provide high tensile strength for tunnel support; after the thin-sprayed material is effectively bonded with the wet-sprayed concrete, it protects the wet-sprayed concrete layer through the "high-strength membrane" effect, and has a good sealing effect in the surrounding rock support with complex hydrogeological conditions such as large water inflow. This support method takes into account the characteristics of rigid support and flexible support. By replacing the metal mesh of the anchor mesh spraying support, it solves the problems of easy corrosion of the metal mesh, low effective utilization rate, and low mesh hanging efficiency; this support technology can improve the construction environment and has excellent green environmental protection characteristics.

[0073] The combined support method provided by the embodiment of the present invention can provide initial tension force to enhance the stability of the surrounding rock, reduce the deformation of the rock mass around the tunnel, and control the loosening and collapse of fragments by installing prestressed anchor rods in the loose surrounding rock outside the tunnel, and installing prestressed anchor cables in the shell structure, loose surrounding rock, and stable surrounding rock outside the loose surrounding rock. By covering the wet sprayed concrete layer with a reactive thin spray material layer, the two are consolidated, taking into account the characteristics of rigid support and flexible support, and having a good support effect on soft rock large deformation tunnels; this support method replaces the traditional anchor net spraying support method, avoiding the high risk of brittle geological disasters, easy corrosion of metal nets, low effective utilization rate, low net hanging efficiency, etc., can improve the construction environment, and has excellent green environmental protection characteristics.

[0074] In one embodiment provided by the present invention, the reactive thin spraying material layer is formed by using a two-component elastomer nano-modified material, which is heated and pressurized by a thin spraying machine and mixed evenly before being sprayed and cured. This embodiment uses a two-component elastomer nano-modified material and a composite spraying process to achieve the formation of a reactive thin spraying material layer, which has excellent self-repairing properties and mechanical strength, and significantly improves the corrosion resistance and service life of the coating.

[0075] It should be noted that in this embodiment, the thin spray machine is a new type of spraying equipment. The thin spray machine is mainly composed of a liquid material container, a pneumatic control system, a paint pump, an electromagnetic control valve, a nozzle and other components. It uses a pneumatic control system and an electromagnetic control valve to control the opening and closing of the liquid material pump so that the liquid material is sprayed from the liquid material container through the nozzle. After the liquid material is sprayed, the shape and thickness of the spraying are controlled by the pneumatic control system. The position of the nozzle can be freely adjusted to meet different spraying requirements.

[0076] The thin-film spraying machine can form a uniform and dense protective film. By changing the angle of the nozzle and the coating thickness, the thin-film spraying machine can control the amount of material used, save the use of spraying materials, and improve cost-effectiveness. In addition, the thin-film spraying machine can achieve fast and uniform spraying, reduce the labor intensity of workers, and improve construction efficiency.

[0077] Furthermore, in an embodiment provided by the present invention, the elastomer nano-modified material includes component A and component B, and component A and component B are mixed and reacted at the nozzle.

[0078] Specifically, component A may be composed of a basic elastomer material, a nanofiller and an additive.

[0079] The basic elastomer material can be: thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), natural rubber, synthetic rubber (such as styrene-butadiene rubber SBR, nitrile rubber NBR), etc. The basic elastomer material serves as the main matrix of the modified material.

[0080] Nanofillers can be nano-silicon dioxide, nano-calcium carbonate, carbon nanotubes, graphene or their derivatives, etc., which are used to enhance the mechanical properties, wear resistance, thermal conductivity or electrical conductivity of the material.

[0081] Additives include plasticizers, antioxidants, light stabilizers, UV stabilizers, etc. to improve processing performance and long-term stability.

[0082] Component B may consist of: a crosslinking agent or curing agent, a catalyst and a diluent or solvent.

[0083] Crosslinking agents / curing agents are used for the crosslinking reaction of the basic elastomer material in component A, such as isocyanates, peroxides, metal salts, etc., so that the material can cure quickly after mixing.

[0084] Catalysts are used to accelerate the chemical reaction between component A and component B, increasing the curing speed and efficiency.

[0085] The diluent / solvent is used to adjust the viscosity of the system to facilitate efficient mixing and uniform distribution of the two components at the spray outlet.

[0086] In this method, a mixing chamber can also be set upstream of the spray port for mixing reaction. Specifically, a two-component spray system can be used, wherein component A and component B enter the mixing chamber through independent delivery pipes, and in the mixing chamber, high-speed shearing, static mixing elements or dynamic mixers (such as turbine mixers) are used to achieve full mixing of the two components in the mixing chamber. By accurately controlling the flow ratio, spray pressure and temperature of component A and component B, it is ensured that the mixed materials undergo a rapid and uniform cross-linking reaction at the spray port.

[0087] Furthermore, a flow channel structure may be designed inside the nozzle to promote further mixing of the two components and ensure that the ejected material has consistent physical and chemical properties.

[0088] The elastomer nano-modified material solidifies quickly at the spray outlet, which can improve production efficiency. The elastomer nano-modified material has excellent mechanical properties, wear resistance and weather resistance. Through precise control of the mixing and spraying process, high-precision and high-quality coatings or molded parts can be achieved.

[0089] Furthermore, in one embodiment provided by the present invention, component A is a semi-prepolymer: the semi-prepolymer is prepared by mixing isocyanate, polyether diol, a second diluent and self-repairing microcapsules as raw materials, and reacting the raw materials in an inert gas to obtain:

[0090] Component B includes amino-terminated polyether, composite metal phase change microcapsule emulsion, amine chain extender and metal micropowder: the preparation method of self-repairing microcapsules includes:

[0091] S1, ① prepare reaction pre-emulsion M:

[0092] The initiator, the emulsifier and the water are mixed, and the pH value of the obtained solution is adjusted to 3-4 after emulsification to obtain a reaction pre-emulsion M: the emulsifier is one or more of an anionic surfactant and a nonionic surfactant; the initiator is benzoyl peroxide or azobisisobutyronitrile;

[0093] The mass ratio of emulsifier to water is 1.5-4:60;

[0094] ②Preparing reaction pre-emulsion N: dispersing and emulsifying the first diluent, alkyd resin and methyl methacrylate aqueous solution to obtain reaction pre-emulsion N; the first diluent is one or more of di-n-octyl phthalate, dibutyl benzyl phthalate, ethyl carbonate and propyl carbonate;

[0095] The mass ratio of the first diluent to the alkyd resin shall not exceed 1:1.2;

[0096] S2, mixing the reaction pre-emulsion M and the reaction pre-emulsion N uniformly, heating to 60-80° C., and keeping the temperature for 3-5 hours to obtain a reaction emulsion;

[0097] S3, washing and drying the reaction emulsion to obtain self-repairing microcapsules;

[0098] The second diluent is one or more of di-n-octyl phthalate, dibutyl benzyl phthalate, ethyl carbonate and propyl carbonate.

[0099] Through the self-healing microcapsule synthesis method and the preparation method of composite metal phase change microcapsule emulsion, the dual self-healing mechanism of the coating is realized, which significantly improves the corrosion resistance and mechanical strength of the coating and extends the service life of the coating.

[0100] Furthermore, in S1, the emulsifier is a compound of one or more of anionic surfactants and nonionic surfactants, such as an alkane sodium salt emulsifier, an acid anhydride emulsifier, an enol emulsifier, a polyether emulsifier or a polyester emulsifier.

[0101] Furthermore, the metal powder is one or more of aluminum, zinc and magnesium.

[0102] Furthermore, the isocyanate is one or more of diphenylmethane diisocyanate, xylylene diisocyanate, toluene diisocyanate and polymethylene polyphenyl isocyanate.

[0103] Furthermore, the polyether diol is one or more of polypropylene glycol, polytetramethylene glycol and tetrahydroxypropylethylenediamine.

[0104] Furthermore, the amino polyether is a polyether diamine and / or triamine.

[0105] Furthermore, the chain extender is selected from one or more of dimethylthiotoluenediamine, diethyltoluenediamine, 1,4-bis-sec-butylaminobenzene, 4,4'-bis-sec-aminodiphenylmethane, isophoronediamine, and diaminodimethylthiotoluene.

[0106] Furthermore, the preparation method of the composite metal microcapsule emulsion in component B comprises the following steps:

[0107] Step 1, preparing a composite phase change material core material dispersion: fully mixing a low melting point metal alloy and paraffin wax in a preset ratio, and dispersing under the action of mechanical shear force to obtain a composite phase change material core material dispersion; depending on the ratio of the added metal and paraffin wax, there can be two types of composite phase change material core material dispersions, namely, small paraffin droplets are wrapped by metal or small metal droplets are wrapped by paraffin wax;

[0108] Step 2, preparing a shell material solution: mixing the shell material and water in a preset ratio to obtain a shell material solution;

[0109] Step 3: preparing low melting point metal phase change microcapsules: under stirring at 45-60°C, dropwise add the core material dispersion obtained in step 1 to the shell material solution obtained in step 2, and then dropwise add acetic acid to adjust the pH of the solution to 3.5-4.5;

[0110] After the core material dispersion liquid is added dropwise, the reaction liquid is cooled to below 10°C, and formaldehyde solution or glutaraldehyde solution is added for cross-linking and curing. After curing, the reaction is terminated, and the mixture is filtered, washed to neutrality, and air-dried to obtain composite metal microcapsules.

[0111] Step 4, preparing a composite metal microcapsule emulsion: mixing the low melting point composite metal phase change microcapsules obtained in step 3 with epoxy resin to finally obtain a composite metal microcapsule emulsion.

[0112] Furthermore, in step 1, the low melting point metal is a gallium indium tin alloy, and the weight ratio of gallium indium tin is 0-90:0-90:0-60; the weight ratio excluding gallium indium tin is 0:0:0.

[0113] Furthermore, in step 1, the weight ratio of the low melting point metal to the paraffin is 1-5:1-5.

[0114] Furthermore, in step 2, the mass fraction of acetic acid is selected to be 10%,

[0115] Furthermore, the mass fraction of formaldehyde in the formaldehyde solution in step three is 37%.

[0116] Furthermore, the mass fraction of glutaraldehyde in the glutaraldehyde solution in step three is 10%.

[0117] Furthermore, in step 2, the shell material is a natural polymer material; and the weight ratio of the shell material to water is 1:10-100.

[0118] Furthermore, the natural polymer material includes gelatin and gum arabic.

[0119] Furthermore, in step 4, the mass ratio of the composite metal microcapsule to the epoxy resin is 0-1:2-10, excluding 0:2-10.

[0120] Furthermore, the elastomer nano-modified material is treated by ultrasonic emulsification to improve the uniformity and reactivity of the components, promote the mutual reaction between the components, and improve the cross-linking degree of the components in the coating.

[0121] Furthermore, when the elastomer nano-modified material is used, it is evenly coated on the surface of the target object to form a scratch self-repairing spray protective coating; when scratches are generated on the coating surface, the low-melting-point metal microcapsules in the coating material are broken, and the low-melting-point metal and metal micropowder therein are mixed to form an alloy. Because the alloy has a high melting point, it is solid at room temperature, which is equivalent to forming a solid metal skeleton in the repair area (scratch). Therefore, the mechanical strength of the repair area can be greatly improved, solving the risk of low strength of the repair area in the traditional method, which easily causes the object to crack again.

[0122] The self-repairing coating obtained by the self-repairing microcapsules, wherein the self-repairing microcapsules and the composite metal microcapsules can realize dual self-repair of the coating at room temperature, improve the corrosion resistance of the coating after damage, and extend the service life of the coating.

[0123] This elastomer nano-modified material uses a composite metal microcapsule. Unlike traditional metals, the phase change material based on a composite of low-melting-point metals and paraffin has many advantages such as no corrosion, no supercooling, and high safety. It overcomes the inherent shortcomings of organic and inorganic salt phase change materials and gives capsules and application products additional functions. Compared with existing self-healing microcapsules, it reacts more quickly, therefore accelerating the repair effect, achieving timely repair of cracks, and avoiding more serious consequences and higher repair costs.

[0124] The elastomer nano-modified material has a compact structure of prepared self-repairing microcapsules and composite metal microcapsules, and is easy to mix with the same coating to obtain a self-repairing coating with good combination of microcapsules and substrate.

[0125] Further, in one embodiment provided by the present invention, the mixing ratio of component A and component B is 1:1. That is, when preparing or mixing the two components, their amounts are completely equal. This equal proportion mixing is usually used to ensure that the two components can fully react, be evenly dispersed, or achieve specific performance requirements.

[0126] Mixing component A and component B in equal proportions can ensure that the reaction between them can proceed fully, thereby improving the purity and yield of the product and achieving balanced performance.

[0127] Furthermore, in an embodiment provided by the present invention, the mass fractions of each component in the raw material are: 40-60 parts of isocyanate, 40-50 parts of polyether diol, 1-10 parts of self-healing microcapsules and 1-10 parts of the second diluent;

[0128] The mass proportions of each component in component B are: 40-60 parts of amino-terminated polyether, 30-50 parts of amine chain extender, 1-20 parts of composite metal microcapsule emulsion and 1-5 parts of metal powder.

[0129] When using this material, it is evenly coated on the surface of the target object to form a scratch self-repairing spray protective coating; when scratches appear on the coating surface, the low-melting-point metal microcapsules in the coating material are broken, and the low-melting-point metal and metal micropowder are mixed to form an alloy. Because the alloy has a high melting point and is solid at room temperature, it is equivalent to forming a solid metal skeleton in the covered area. Therefore, the mechanical strength of the covered area can be greatly improved.

[0130] In a specific embodiment, the thin spray material used is a two-component, high-performance elastomer nano-modified spray material with buffer protection performance, dense and seamless coating, good flexibility, strong adhesion, good elasticity and toughness, and can adapt to large deformation substrates; high early strength, can be cured within a few minutes, and has good flame retardant and antistatic capabilities; excellent corrosion resistance and chemical resistance such as acid, alkali, salt, etc.; excellent waterproof and moisture-proof performance. Its performance is shown in Table 1 and Table 2:

[0131] Table 1

[0132] <![CDATA[Density / (g / cm 3 )]]> 1.1 Consolidation time / min 8~15(Surface dry) Tensile strength / MPa >25MPa Tear strength / (kN / m) >140(ASTM D-624) Impact resistance (kg*m) 2.4 (ASTM D2794) Adhesion (steel substrate, MPa) >12(HG / T 3831-2006)

[0133] Table 2

[0134] Substrate temperature 10℃ 20℃ 30℃ Surface drying time / min 15 12 8 Walking intensity time / min 90 60 45 Complete curing time / d 12 7 5

[0135] In one embodiment provided by the present invention, the thickness of the wet sprayed concrete layer is 100 mm, and the surface roughness of the wet sprayed concrete layer does not exceed a preset threshold; the thickness of the reactive thin sprayed material layer is 3 mm.

[0136] The thickness of the wet shotcrete layer is 100mm, which can meet the requirements of engineering structure strength, stability and durability. The thickness of 100mm can provide sufficient support and protection to prevent erosion of the external environment and damage to the internal structure.

[0137] Surface roughness is an important indicator to measure the degree of irregularity of the concrete surface. By controlling the surface roughness, the unevenness of the tunnel surrounding rock surface can be smoothed, thereby avoiding stress concentration, thereby ensuring that the reactive thin spraying material layer can be tightly attached to the wet spraying concrete layer to form a solid structural whole.

[0138] A 3mm layer of reactive spray material is sufficient to provide the necessary protection without significantly increasing the weight or cost of the overall structure. Reactive spray materials generally have excellent adhesion, chemical corrosion resistance and wear resistance, and can cure in a short time and form a hard protective layer.

[0139] This embodiment achieves an optimal balance of structural strength, stability and durability by precisely controlling the thickness and surface roughness of the wet shotcrete layer and the reactive thin shotcrete layer. The wet shotcrete layer provides a solid base, while the reactive thin shotcrete layer enhances the durability and protection of the surface.

[0140] In one embodiment provided by the present invention, the strength grade of the shotcrete layer is C20, the water-cement ratio is 0.65, the cement-sand ratio is 0.37, and the water reducer is 0.3% of the mass of the cementitious material. The wet shotcrete is bonded to the tunnel surrounding rock to form a closed layer, which provides high flexural strength for the tunnel and effectively bears the tunnel surrounding rock pressure, preventing the tunnel rock blocks from loosening and collapsing and large deformation.

[0141] Specifically, the strength grade of the sprayed concrete layer is C20: it means that the standard value of the compressive strength of the concrete is 20MPa.

[0142] The water-cement ratio is the ratio of the mass of water in concrete to the mass of cement (or cementitious material), which directly affects the strength, durability and working performance of concrete. A water-cement ratio of 0.65 not only ensures the strength requirements of concrete, but also takes into account the operability of construction.

[0143] The lime-sand ratio is the ratio of the mass of cement (or cementitious material) to the mass of sand in concrete. This ratio has an important influence on the strength, workability and cost of concrete. A lime-sand ratio of 0.37 can balance the strength, workability and cost of concrete.

[0144] Water reducer is an admixture that can significantly improve the working performance of concrete. It can increase the fluidity of concrete without increasing the amount of water, thereby improving the construction performance of concrete. At the same time, the use of water reducer can also reduce the bleeding and segregation of concrete, and improve the homogeneity and strength of concrete. 0.3% water reducer can effectively improve the working performance of concrete without significantly increasing the cost.

[0145] This embodiment optimizes concrete performance and improves construction efficiency by precisely controlling parameters such as the strength grade, water-cement ratio, cement-sand ratio, and water-reducing agent dosage of the shotcrete layer.

[0146] The present invention also provides a combined support device, see Figures 2 to 5 , the device comprises:

[0147] Prestressed anchor rod 1, wet sprayed concrete layer 3, prestressed anchor cable 2 and reactive thin sprayed material layer 4. The reactive thin sprayed material layer 4 has high tensile strength and takes into account both rigid support and flexible support.

[0148] The above-mentioned prestressed anchor rod 1 is installed in the loose surrounding rock outside the tunnel, and the anchor head of the prestressed anchor rod 1 is anchored on the surrounding rock inside the tunnel. The main function of the prestressed anchor rod 1 is to provide initial tension to enhance the stability of the surrounding rock and reduce the deformation of the rock mass around the tunnel. The loose and broken area surrounding rock is anchored by the pre-tightening force of the anchor rod to control the loosening and collapse of the broken pieces.

[0149] The wet sprayed concrete layer 3 covers the surrounding rock on the inner side of the tunnel and covers the anchor head to form a shell structure. That is to say, the anchor head of the spear rod is fixed first, and then the wet sprayed concrete layer 3 is applied. Because the wet sprayed concrete layer 3 has a certain spraying layer thickness, it can smooth the unevenness of the tunnel surrounding rock surface, thereby avoiding stress concentration, providing a relatively flat attachment surface for the subsequent reactive thin sprayed material layer 4, and improving the support strength. The wet sprayed concrete layer 3 forms a protective shell structure, which can not only provide additional support, but also prevent the surrounding rock from further weathering or peeling. The wet sprayed concrete layer 3 and the prestressed anchor rod 1 together form a solid outer shell, which can provide high flexural strength for the tunnel and effectively bear the pressure of the tunnel surrounding rock.

[0150] The prestressed anchor cable 2 is installed in the shell structure, the loose surrounding rock and the stable surrounding rock outside the loose surrounding rock, and the anchoring end of the prestressed anchor cable 2 is anchored on the shell structure. The anchoring end of the anchor cable is anchored on the shell structure so that they can provide additional tension and further enhance the supporting effect of the tunnel. The use of the prestressed anchor cable 2 helps to disperse and resist the pressure of the surrounding rock in a larger range. Through the suspension effect of the prestressed anchor cable 2, the shell structure composed of the anchor rod and the concrete layer is anchored in the deep stable rock layer, so that the surrounding rock in the loose area and the deep stable surrounding rock become one, further improving the stability of the tunnel surrounding rock.

[0151] The reactive thin spray material layer 4 is bonded to the shell structure and the anchoring end formed by wet spraying concrete, and the reactive thin spray material layer 4 is formed by a composite spraying process. Specifically, the reactive thin spray material layer 4 contains a variety of material components and is formed by a composite spraying process. These components will react chemically after mixing, thereby enhancing the strength and adhesion of the material. The reactive thin spray material layer 4 can provide additional support strength and ensure close bonding between all support components.

[0152] The above-mentioned reactive thin-sprayed material layer 4 has good toughness and tensile properties, and can provide high tensile strength for tunnel support. By spraying reactive thin-sprayed materials, an integral support structure of anchor-sprayed-anchor-sprayed is formed. After the thin-sprayed material is effectively bonded with the wet-sprayed concrete, it plays a protective role on the wet-sprayed concrete layer 3 through the "high-strength membrane" effect, and has a good sealing effect in the surrounding rock support with complex hydrogeological conditions such as large water inflow.

[0153] The combined support device provided by the embodiment of the present invention can provide initial tension force to enhance the stability of the surrounding rock, reduce the deformation of the rock mass around the tunnel, and control the loosening and collapse of fragments by installing the prestressed anchor rod 1 in the loose surrounding rock outside the tunnel, and installing the prestressed anchor cable 2 in the shell structure, the loose surrounding rock, and the stable surrounding rock outside the loose surrounding rock. By covering the reactive thin spraying material layer 4 on the wet spraying concrete layer 3, the two are consolidated, taking into account the characteristics of rigid support and flexible support, and having a good support effect on soft rock large deformation tunnels; the support device replaces the traditional anchor net spraying support method, avoiding the high risk of brittle geological disasters, easy corrosion of metal nets, low effective utilization rate, low net hanging efficiency and other problems, can improve the construction environment, and has excellent green environmental protection characteristics.

[0154] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship, but it may also indicate an "and / or" relationship. Please refer to the context for specific understanding.

[0155] In the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0156] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0157] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A combined support method, characterized in that: The method comprises: Step 1: Knock on the top and clean up the floating stones and dangerous rocks on the surface of the tunnel surrounding rock; Step 2: installing anchor rods around the tunnel and applying a first preset preload force to the anchor rods; Step 3: Form a wet shotcrete layer around the tunnel by spraying wet shotcrete, and make the wet shotcrete layer cover the tail end of the anchor bolt; Step 4: Install the anchor cable and apply a second preset preload force to anchor the shell structure consisting of the anchor rod and the concrete layer in the deep stable rock formation; Step 5: Use a composite spraying process to spray the reactive thin-spray material on the surface of the wet-sprayed concrete layer, and form a reactive thin-spray material layer with elastomeric protective properties on the wet-sprayed concrete layer and the outside of the anchor cable.

2. The combined support method according to claim 1, characterized in that: The reactive thin-spray material layer is formed by using a two-component elastic nano-modified material, which is heated and pressurized by a thin-spray machine, mixed evenly, and then sprayed and cured.

3. The combined support method according to claim 2, characterized in that: The elastomer nano-modified material comprises component A and component B, and the component A and the component B are mixed and reacted at a spray outlet.

4. The combined support method according to claim 3, characterized in that: The component A is a semi-prepolymer: the semi-prepolymer is prepared by using isocyanate, polyether diol, a second diluent and self-repairing microcapsules as raw materials, and the raw materials are mixed and reacted in an inert gas to obtain: The B component includes amino-terminated polyether, composite metal phase change microcapsule emulsion, amine chain extender and metal powder. The preparation method of the self-repairing microcapsule includes: S1, ① prepare reaction pre-emulsion M: The initiator, the emulsifier and the water are mixed, and the pH value of the obtained solution is adjusted to 3-4 after emulsification to obtain a reaction pre-emulsion M: the emulsifier is one or more of an anionic surfactant and a nonionic surfactant; the initiator is benzoyl peroxide or azobisisobutyronitrile; The mass ratio of the emulsifier to water is 1.5-4:60; ②Preparing a reaction pre-emulsion N: dispersing and emulsifying a first diluent, an alkyd resin and an aqueous solution of methyl methacrylate to obtain a reaction pre-emulsion N; wherein the first diluent is one or more of di-n-octyl phthalate, dibutyl benzyl phthalate, ethyl carbonate and propyl carbonate; The mass ratio of the first diluent to the alkyd resin is no more than 1:1.2; S2, mixing the reaction pre-emulsion M and the reaction pre-emulsion N uniformly, heating to 60-80° C., and keeping the temperature for 3-5 hours to obtain a reaction emulsion; S3, washing and drying the reaction emulsion to obtain self-repairing microcapsules; The second diluent is one or more of di-n-octyl phthalate, dibutyl benzyl phthalate, ethyl carbonate and propyl carbonate.

5. The combined support method according to claim 4, characterized in that: The mixing ratio of the A component and the B component is 1:

1.

6. The combined support method according to claim 5, characterized in that: The mass fractions of the components in the raw materials are: 40-60 parts of isocyanate, 40-50 parts of polyether diol, 1-10 parts of self-repairing microcapsules and 1-10 parts of the second diluent; The mass proportions of the components in the B component are: 40-60 parts of amino-terminated polyether, 30-50 parts of amine chain extender, 1-20 parts of composite metal microcapsule emulsion and 1-5 parts of metal powder.

7. The combined support method according to claim 1, characterized in that: The thickness of the wet sprayed concrete layer is 100 mm, and the surface roughness of the wet sprayed concrete layer does not exceed a preset threshold; The thickness of the reactive thin spray material layer is 3 mm.

8. The combined support method according to claim 1, characterized in that: The wet sprayed concrete layer has a strength grade of C20, a water-cement ratio of 0.65, a cement-sand ratio of 0.37, and a water reducer of 0.3% of the mass of the cementitious material.

9. A combined support device, characterized in that: The device comprises: A prestressed anchor rod, wherein the prestressed anchor rod is installed in the loose surrounding rock outside the tunnel, and the anchor head of the prestressed anchor rod is anchored on the surrounding rock inside the tunnel; A wet shotcrete layer, wherein the wet shotcrete layer covers the surrounding rock inside the tunnel and covers the anchor head to form a shell structure; A prestressed anchor cable, wherein the prestressed anchor cable is installed in the shell structure, the loose surrounding rock, and the stable surrounding rock outside the loose surrounding rock, and the anchoring end of the prestressed anchor cable is anchored on the shell structure; A reactive thin spray material layer is bonded to the shell structure and the anchoring end, and the reactive thin spray material layer is formed by a composite spraying process.

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