CN117536652A

CN117536652A - High-stress soft rock and surrounding rock crushing supporting construction method and material based on deformation control

Info

Publication number: CN117536652A
Application number: CN202311386797.9A
Authority: CN
Inventors: 李豪; 卫婧; 戴诗媛; 李瑞明
Original assignee: Beijing Resident New Material Technology Co ltd
Current assignee: Beijing Resident New Material Technology Co ltd
Priority date: 2023-10-24
Filing date: 2023-10-24
Publication date: 2024-02-09
Anticipated expiration: 2043-10-24
Also published as: CN117536652B

Abstract

A supporting construction method and a material for high-stress soft rock and broken surrounding rock based on deformation control comprise the following steps: constructing anchor rod holes on the surface of a structure to be supported, installing a first reinforcing mesh, and fixing the first reinforcing mesh by using anchor rods; spraying a first concrete material on the surface of the first reinforcing mesh to form a buffer layer, wherein the tail end of the anchor rod penetrates out of the buffer layer; after the buffer layer is initially set, spraying a layer of curing agent on the surface of the buffer layer; a second reinforcing mesh is arranged on the surface of the buffer layer through the anchor rod; spraying a second concrete material on the second reinforcing mesh as a substrate to construct a supporting layer; and spraying a layer of curing agent on the surface of the supporting layer. The method has the advantage of better supporting stability in the supporting process of the soft rock and the surrounding rock with larger deformation.

Description

High-stress soft rock and surrounding rock crushing supporting construction method and material based on deformation control

Technical Field

The invention relates to the technical field of support, in particular to a support construction method and a material for high-stress soft rock and broken surrounding rock based on deformation control.

Background

At present, anchor spraying support, anchor rope spraying support, arch support or cast-in-place concrete and other support forms are widely applied to water conservancy projects, railways, mine roadways, highways, roadway projects and the like. The main obstacles and threats in the rapid construction process of the roadway are high-ground stress soft rock and broken surrounding rock. In the process of tunnel excavation, the construction progress is restricted due to the problems of soft and firm surrounding rock surface soil layers, poor integrity, poor safety and reliability and the like. The problem is obvious in the construction process of the coal mine tunnel, and the safety condition of tunnel support is seriously influenced.

In the related art, a plurality of forms such as a metal arch, an anchor net spray, an anchor rope and a reinforced concrete pouring support are adopted for combined support, for example, chinese patent publication No. 2023104284497 discloses a mine tunnel support structure which comprises an inner reinforced net sheet, reinforced anchor rods and reinforced net columns, wherein the inner reinforced net sheet is paved on the inner side surface of a tunnel, the reinforced anchor rods are used for anchoring the inner reinforced net sheet, the reinforced net columns are perpendicular to the inner reinforced net sheet and are arranged at intervals, outer reinforced net sheets are arranged on the outer reinforced net sheets, stiffening ribs are arranged on the outer reinforced net sheets at intervals, and foam concrete materials are filled in a space formed by the inner reinforced net sheet, the reinforced net columns and the outer reinforced net sheets.

However, as the mining depth of the roadway increases, particularly in the roadway with high-stress soft rock and broken surrounding rock, concentrated stress and offset stress in the roadway soft rock and the surrounding rock are easily increased, so that the denaturation characteristics of the soft rock and the surrounding rock are obviously changed, and the deep ground stress of the roadway is easily propagated, so that the deep roadway soft rock and the surrounding rock are unstable, the roadway surrounding rock is easily deformed greatly, the application of the supporting structure under the situation is limited, particularly when the deformation reaches 50-100mm, the foam concrete material is subjected to deformation and damage phenomena such as cracking, breaking, loosening and falling, and the supporting effect of the supporting structure is lost, so that the problem needs to be solved.

Disclosure of Invention

In order to solve the problems, the embodiment of the application provides a supporting construction method and a material for high-stress soft rock and broken surrounding rock based on deformation control, which have the advantage of better supporting stability in the supporting process of the soft rock and the surrounding rock with larger deformation.

For this reason, the following technical solutions are adopted in the embodiments of the present application:

in a first aspect, an embodiment of the present application provides a method and a material for supporting high-stress soft rock and broken surrounding rock based on deformation control, including the following steps:

Constructing anchor rod holes on the surface of a structure to be supported, installing a first reinforcing mesh, and fixing the first reinforcing mesh by using anchor rods;

spraying a first concrete material on the surface of the first reinforcing mesh to form a buffer layer, wherein the tail end of the anchor rod penetrates out of the buffer layer;

after the buffer layer is initially set, spraying a layer of curing agent on the surface of the buffer layer;

a second reinforcing mesh is arranged on the surface of the buffer layer through the anchor rod;

spraying a second concrete material on the second reinforcing mesh as a substrate to construct a supporting layer;

spraying a layer of curing agent on the surface of the supporting layer;

the first concrete material comprises the following components in parts by weight: 100 parts of cement, 210-225 parts of rubber particles, 60-80 parts of admixture, 10-20 parts of impervious fiber, 2-5 parts of accelerator, 3-7 parts of foaming agent, 3-5 parts of water reducer, 100-120 parts of water and 15-20 parts of early strength agent; the impervious fiber consists of glass fiber, viscose fiber, polyoxymethylene fiber and polyester fiber in a weight ratio of 2-4:3-4:2-4:1; the glass fiber is hollow fiber with two closed ends, and the glass fiber is filled with an anti-cracking repair material; the anti-cracking repair material comprises acrylic resin, nano aluminum hydroxide, aluminum potassium sulfate and micro silicon powder in a weight ratio of 2-3:1-2:1-2:1;

The second concrete material comprises 20-60 parts of modified cement, 20-40 parts of admixture, 3-6 parts of curing agent, 5-15 parts of reinforcing fiber, 0.5-1.5 parts of water reducer, 0.01-0.05 part of defoamer, 2-4 parts of thixotropic agent and 80-120 parts of high-strength aggregate.

In this embodiment, this application through setting up double-deck reinforcing bar net structure, can effectively improve the stability of strutted, strengthen the bearing capacity of country rock. The double-layer reinforcing steel bar net and the anchor rod structure provide base support for the structures of the buffer layer and the supporting layer, and the buffer layer formed by the first concrete material has enough flexibility to bear large deformation generated by the expansion type soft rock and the high ground stress soft rock so as to convert the expansion energy and the deformation energy of the buffer layer, and also has enough large strength in a specific time period so as to control destructive deformation of the expansion type soft rock and the high ground stress soft rock so as to meet the supporting safety and reliability, and has economic benefit. The buffer layer is matched with the supporting layer formed by the second concrete material to form a combined support, and the buffer layer can well release the deformation energy and the expansion pressure of surrounding rock, so that the stress of the supporting layer is greatly reduced, and the reliability of the supporting structure is improved. Meanwhile, the first concrete material and the second concrete material are both constructed by adopting an injection method, and the first concrete material can be coagulated and solidified in a shorter time to form higher strength, so that the construction method has higher construction efficiency; the second concrete material has high strength and high toughness, and is matched with spraying construction operation, so that the application range is wider, construction can be performed under various complex working conditions, and the construction method has better support stability under the condition of having construction efficiency.

Rubber particles in the first concrete material provide better elastic strain performance of the buffer layer, and relatively large deformation generated by surrounding rock is dealt with, and the addition of the impervious fibers can reduce the number of defects such as cracks and hollows in the buffer layer, so that the flexural strength and tensile strength of the buffer layer are improved, the possibility of breakage is reduced, the flexural tensile strength of the buffer layer is enhanced, and the safety and structural stability of the buffer layer are improved. The impervious fiber is composed of glass fiber, viscose fiber, polyoxymethylene fiber and polyester fiber with the weight ratio of 2-4:3-4:2-4:1, the impervious fiber has the advantages of excellent flexibility and dispersibility, the compatibility of the impervious fiber with a concrete matrix is improved, the blended concrete mixture can be kept stable uniformly, the shrinkage and expansion of the system are reduced, the impervious fiber has good stability and is not easy to generate layering phenomenon when being sprayed on the side wall or the top of a structure to be supported, and the glass fiber, viscose fiber, polyoxymethylene fiber and polyester fiber have larger impact strength, can inhibit cracking of concrete due to dry shrinkage, and has better loosening resistance, smaller abrasion, larger impervious pressure and increased tensile strength and flexural strength. The buffer layer is distributed with a plurality of fibers, and the dispersed fibers can reduce the stress of plastic shrinkage of the concrete and improve the cracking resistance of the concrete.

The glass fiber is a high-strength fiber material, can play a role of a reinforcing material in concrete, and improves the tensile strength and toughness of the concrete; the viscose fiber can form adhesion with cement colloid in the concrete, so that the cohesion and shear strength of the concrete are improved, and the overall performance of the concrete is enhanced; the polyoxymethylene fiber has higher tensile modulus and tensile strength, plays a role of a reinforcing material in concrete, and improves the tensile strength of the concrete; the polyester fiber is a high-strength fiber material, plays a role of a reinforcing material in concrete, and improves the tensile strength and toughness of the concrete; the glass fiber, the viscose fiber, the polyoxymethylene fiber and the polyester fiber respectively play roles of reinforcing materials, cracking resistance, permeability resistance, adhesive force increasing, overall performance improving, toughness improving, impact resistance improving, shrinkage cracking controlling, leakage preventing, tensile strength improving and the like in the buffer layer, and jointly improve the performance and durability of the buffer layer structure.

In addition, the glass fiber is filled with an anti-cracking repair material, when the buffer layer is stressed to generate cracks, the glass fiber can release the anti-cracking repair material in the glass fiber to the cracks after being broken by tensile force, and the acrylic resin in the anti-cracking repair material can form firm bonding with the surface of the concrete cracks, fill the concrete cracks and be tightly connected with surrounding concrete structures, so that the bonding strength is enhanced; the nano-hydroxyl aluminum particles have smaller size and high specific surface area, can penetrate into concrete cracks, fill the gaps of the cracks, enhance the closing performance of the cracks, and can form microscopic gel at the cracks, so that the cracking resistance of the concrete is improved, and the expansion of the cracks is effectively inhibited; the aluminum potassium sulfate has gelation property, can react with water in the concrete to generate gelatinous substances, fills concrete cracks, and enhances the continuity and durability of the material; the aluminum potassium sulfate has gelation property, can react with water in the concrete to generate gelatinous substances, fills concrete cracks, enhances the continuity and durability of materials, can generate crystallization products in the curing process of the aluminum potassium sulfate, fills the concrete cracks, forms hard gelatinous bodies and improves the strength and rigidity of the concrete; the micro silicon powder has fine particles and larger specific surface area, can fully fill concrete cracks, fills gaps, improves the closing performance of the cracks, can react with cement colloid in the gelation process to generate silicate colloid, enhances the mechanical property of the concrete, and improves the cracking resistance. That is, when the acrylic resin, the nano aluminum hydroxide, the aluminum potassium sulfate and the micro silicon powder are used together, a synergistic effect can be exerted between the materials, so that a better concrete crack repairing effect can be achieved. First, the acrylic resin has a binding and waterproofing effect, and can firmly adhere to the concrete surface and prevent moisture penetration. Meanwhile, the nano aluminum hydroxide particles can fill gaps of cracks, improve closure performance by forming microscopic gel, and inhibit continuous expansion of the cracks. The aluminum potassium sulfate forms a crystallized product in the gelation process, fills cracks, and enhances the continuity and the durability. The silica fume has filling and strengthening functions, can fully fill cracks, reacts with cement colloid in a gelation reaction, and enhances the mechanical property of concrete.

The addition of the early strength agent and the accelerator can improve the construction rate of the buffer layer, and simultaneously can enable the buffer layer to have better early strength, thereby being convenient for the construction structure of the subsequent support layer.

In addition, the supporting layer constructed by the second concrete material uses components such as high-strength aggregate, reinforcing fiber and the like, so that the stress capacity and bearing capacity of the structure to be supported can be obviously enhanced, and the overall strength is improved. So that the supporting layer can restrain the deformation or crack aggravation of the surrounding rock with its own strength and rigidity. On the other hand, the supporting layer can bear higher pressure, and the supporting layer has better crack resistance due to the high-doping amount of reinforcing fibers, so that the supporting layer can be kept in a non-broken state after bearing pressure exceeding the self compressive strength, and meanwhile, the generation and the expansion of cracks can be effectively prevented, and the supporting capability is improved. The second concrete material has the characteristics of quick solidification and controllable fluidity by adopting measures such as a curing agent, a water reducing agent and the like, and the construction efficiency and quality can be improved. The defoaming agent can reduce the content of bubbles in the concrete and improve the compactness and homogeneity of the concrete, so that the second concrete material can be subjected to thin-layer spraying. The admixture plays roles of filling and refining particles in concrete, and the compactness and strength of the material are improved. The thixotropic agent can increase the viscosity and plasticity of the concrete, so that the second concrete material can realize good slurry coating with the matrix, and the spraying workability of the second concrete material is improved.

By adopting the construction method, the construction procedures can be quickly connected, the construction efficiency is improved, the construction period is shortened, and the construction efficiency and the support stability are both considered.

Above, stock and concrete brickwork are connected, have strengthened the supporting stability of buffer layer and supporting layer, and the buffer layer then can effectually be unloaded the deformation ability and the inflation pressure of country rock, has reduced country rock mechanical state to a certain extent simultaneously, cooperates the supporting layer of high strength for supporting structure reliability is higher.

As one possible embodiment, the cement in the first concrete material is p.o42.5 cement and the modified cement in the second concrete material is p.o42.5r rapid hardening portland cement.

As an implementation mode, the rubber particles are formed by crushing waste natural rubber, and the crushing granularity is 35-40 meshes.

As one possible embodiment, the hollow glass fiber tube has a length of 5 to 15mm, a diameter of 20 to 50 μm, and a hollow ratio of 30 to 60%.

As an implementation mode, the granularity of the micro silicon powder is 120-130 meshes, and the silicon dioxide content of the micro silicon powder is more than 95%.

As an implementation mode, the admixture in the first concrete material and the second concrete material consists of mesoporous molecular sieve and zeolite powder in a weight ratio of 2-4:1.

In the embodiment, the mesoporous molecular sieve and the zeolite powder are porous materials, and because of the electric field and the polarity action in the holes of the mesoporous molecular sieve and the zeolite powder, the mesoporous molecular sieve and the zeolite powder have the characteristic of higher adsorption capacity, and water is a molecule with very strong polarity, so that the water is easily absorbed by the mesoporous molecular sieve and the pumice powder in the concrete mixing process, and along with the prolongation of the hydration age, the water absorbed by the mesoporous molecular sieve and the pumice powder can be continuously released to supplement capillary water in the concrete, improve the capillary water and the relative humidity in the concrete, reduce the capillary negative pressure, effectively reduce the self-shrinkage of the concrete, and simultaneously improve the self-repairing effect of the buffer layer by matching with the anti-cracking repairing material. And the impervious fiber or the reinforcing fiber enters or partially enters the mesoporous molecular sieve and the pumice powder and is adsorbed in the pore diameters of the mesoporous molecular sieve and the pumice powder, and the mesoporous molecular sieve and the pumice powder play a role of connecting nodes, so that the impervious fiber or the reinforcing fiber forms a reticular structure in the cementing layer. When the concrete is stressed, the modified polypropylene fibers have a tendency of separating from the mesoporous molecular sieve and the pumice powder, and the adsorption force between the mesoporous molecular sieve and the pumice powder on the modified polypropylene fibers prevents the modified polypropylene fibers from separating from the mesoporous molecular sieve and the pumice powder, so that the strength of the concrete is improved.

As one possible embodiment, the reinforcing fibers include organic fibers and inorganic fibers in a weight ratio of 1-3:2-5.

In the embodiment, the organic fiber and the inorganic fiber have certain flexibility and ductility, and the addition of the organic fiber and the inorganic fiber can increase the toughness and the cracking resistance of the concrete, effectively prevent the generation and the expansion of cracks and improve the durability of the concrete. The organic fiber and the inorganic fiber can be closely combined with the concrete to form a whole, thereby enhancing the connection performance and the bearing capacity of the concrete.

As an embodiment, the organic fiber is at least one selected from the group consisting of polypropylene fiber, polyvinyl alcohol fiber, and polyoxymethylene fiber.

In the embodiment, the polypropylene fiber has high chemical stability and heat resistance, can keep stable performance under various environmental conditions, and is not easy to corrode and age; meanwhile, the polypropylene fiber has higher tensile strength and toughness, so that the tensile strength and impact resistance of the concrete can be effectively improved, and the durability of the concrete is improved; and the polypropylene fiber has better resistance to alkaline environment, can effectively prevent the corrosion of alkaline substances in the concrete and delay the aging process of the concrete. The polyvinyl alcohol fiber has higher tensile strength and toughness, can effectively resist cracking of concrete, prevent crack expansion and improve the cracking resistance of the concrete. The polyoxymethylene fiber has extremely high strength and rigidity, and can improve the overall strength and rigidity of the concrete structure while reinforcing the concrete; meanwhile, the weight of the polyoxymethylene fiber is light, the dead weight of the concrete structure can be reduced, the engineering load is reduced, and the shock resistance and the overall performance of the structure are improved. The polypropylene fiber has better durability and toughness, the polyvinyl alcohol fiber has the characteristics of shrinkage reduction and crack resistance, and the polyoxymethylene fiber has high strength and corrosion resistance. The proper organic fiber materials are selected according to specific requirements and use environments, so that the respective advantages of the organic fiber materials can be exerted, and the performance and durability of the concrete are improved.

As an embodiment, the inorganic fiber is at least one selected from basalt fiber, sepiolite fiber and steel fiber.

In the embodiment, the basalt fiber is an inorganic fiber material formed by melting and wiredrawing basalt ore at high temperature, has higher tensile strength, can effectively enhance the tensile strength and impact resistance of concrete, has better tolerance to alkaline environment, can effectively delay the corrosion of alkaline substances in the concrete, and improves the durability of the concrete. The sepiolite fiber is an inorganic fiber material formed by melting and wiredrawing natural sepiolite ore at high temperature, has good resistance to corrosive substances such as acid, alkali and the like, and can maintain the durability and stability of a concrete structure; the sepiolite fiber has light weight, can reduce the dead weight of a concrete structure, reduce engineering load and improve the earthquake resistance and the overall performance of the structure. The steel fiber is an inorganic fiber material formed by drawing and cutting high-strength steel, has extremely high tensile strength and toughness, and can remarkably improve the tensile strength, impact resistance and crack resistance of concrete; meanwhile, the steel fibers can effectively improve the earthquake resistance of the concrete and increase the ductility and bearing capacity of the concrete structure.

The basalt fiber has high strength, high temperature resistance and alkali resistance; sepiolite fiber has the characteristics of excellent heat insulation performance, corrosion resistance and light weight; the steel fiber has extremely high strength, shock resistance and durability. The proper inorganic fiber materials are selected according to specific requirements and use environments, so that the respective advantages of the inorganic fiber materials can be exerted, and the performance and durability of the concrete are improved.

As one possible embodiment, the thixotropic agent comprises a weight ratio of 0.2 to 0.8:2 to 5:2-5, nano alumina fiber, nano silicon oxide fiber and nano carbon fiber.

In this embodiment, the nano alumina fibers can increase the viscosity and viscosity of the concrete and improve its dynamic viscoelastic properties. The nano silicon oxide fiber has higher surface area and pore structure, can increase the cohesion and viscosity of concrete and improve the cracking resistance of the concrete. The nano carbon fiber has higher strength and rigidity, and can increase the tensile strength and toughness of concrete. Meanwhile, the nano aluminum oxide fiber, the nano silicon oxide fiber and the nano carbon fiber have larger specific surface area and good dispersibility, and can form a net structure and tiny fiber bundles in the concrete, so that the fluidity of the concrete is increased, and the working performance and fluidity of the concrete are improved; in addition, the nano aluminum oxide fiber, the nano silicon oxide fiber and the nano carbon fiber have higher tensile strength and toughness, and can effectively prevent crack propagation and resist the influence of external stress, thereby improving the cracking resistance and the shock resistance of the concrete. Furthermore, the nano aluminum oxide fiber and the nano silicon oxide fiber have higher strength and hardness, and can form a 3D network structure in the concrete, so that the strength, the rigidity and the durability of the concrete are improved. The nano carbon fiber has higher tensile strength and modulus, and can further improve the mechanical property of the concrete. Finally, the nano aluminum oxide fiber, the nano silicon oxide fiber and the nano carbon fiber have good chemical stability and corrosion resistance, can effectively block the penetration of moisture and oxygen, reduce the pores and microcracks in the concrete, and improve the durability and the impermeability of the concrete.

The nano aluminum oxide fiber, the nano silicon oxide fiber and the nano carbon fiber play a synergistic role in the thixotropic agent in the aspects of improving the fluidity, the cracking resistance, the mechanical property, the durability and the like. The two components are matched with each other for use, so that a better effect can be achieved, and meanwhile, the proportion can be adjusted according to specific requirements to obtain the best engineering performance.

As an implementation mode, the second concrete material further comprises 5-8 parts of polyacrylate and 2-10 parts of sodium alginate.

In this embodiment, the polyacrylate has good dispersibility and thickening ability, and can significantly improve the fluidity of concrete, making it easier for spray construction. Sodium alginate is a natural gelatinizer with extremely strong adhesiveness and cohesiveness, and the addition of sodium alginate can effectively improve the cohesiveness of concrete and strengthen the cohesiveness between concrete and aggregate, thereby improving the tensile strength and the peeling resistance of concrete; meanwhile, sodium alginate is easy to dissolve in water and can form viscous liquid, so that the sodium alginate has certain bonding capability on modified polypropylene fibers, the reinforcing fibers are fully mixed with each component in concrete, raw materials can be fully mixed, and meanwhile, the sodium alginate also has certain hygroscopicity, so that the sodium alginate has the cracking prevention effect in the later use process of the concrete, the service life and strength of the concrete are improved, the sodium alginate can be added to produce synergistic effect with polyacrylate, the cohesive force and the bonding property of the concrete can be improved, the separation rate of material components is reduced, the uniformity and the workability are improved, the setting time of the concrete is adjusted, and the impermeability of the concrete is further improved. In addition, the cooperation of the two is also shown in the following steps: the polyacrylate and the sodium alginate have good waterproof effect, can fill pores and microcracks in the concrete, reduce the penetration and leakage of moisture, improve the impermeability of the concrete and ensure the durability of the structure. The polyacrylate and the sodium alginate have a certain protective effect on the concrete, can reduce shrinkage and cracking of the concrete, prevent corrosion and damage of external factors, and improve the durability and long-term stability of the concrete.

As an implementation manner, the curing agent comprises the following components in parts by weight: 7-10 parts of ethylene-vinyl acetate copolymer, 15-25 parts of sodium silicate, 25-30 parts of acrylic ester copolymer emulsion, 2-5 parts of polyethylene wax, 5-10 parts of sodium dodecyl benzene sulfonate, 1-3 parts of dodecyl alcohol ester, 10-15 parts of sodium alkyl naphthalene sulfonate and 15-30 parts of sodium carboxymethyl cellulose.

In the embodiment, the components in the curing agent can cooperate to form a protective film covering the surface of the concrete, so that the moisture on the surface of the concrete can be prevented from being too fast, the moist curing of the interior of the concrete is promoted, and meanwhile, the invasion and damage of foreign matters are avoided, so that the concrete is cured and protected, and the durability of the concrete is improved.

Specifically, the ethylene-vinyl acetate copolymer can form a protective film, can effectively prevent the volatilization of surface moisture after curing of the curing agent, and can prevent the invasion of foreign substances due to the elasticity of the protective film, thereby realizing the functions of water retention and protecting the surface of concrete. Sodium silicate can permeate into capillary holes of concrete to form a silicic acid colloid, and a compact protective film is formed through the gelatinization of the silicic acid colloid, so that the effect of protecting the inside of the concrete is realized. In addition, the permeability of the curing agent can be improved, the permeability of the curing agent into the concrete is promoted, and the protection and the permeability of the curing agent can be exerted to the maximum when the curing agent is cooperated with other components. The acrylic ester copolymer emulsion can enhance the weather resistance and the adhesiveness of the curing agent and promote the curing agent to form a complete protective film on the surface of concrete. The polyethylene wax can improve the wear resistance and chemical resistance of the curing agent, thereby enhancing the protection effect of the curing agent. The sodium dodecyl benzene sulfonate, the dodecyl alcohol ester and the sodium alkyl naphthalene sulfonate are used as surfactant substances, so that the surface tension of the curing agent can be reduced, the curing agent can more easily permeate into capillary pores on the surface of the concrete, and the permeability of the curing agent is promoted. In addition, they can also improve the stability and lubricity of the curing agent so that it covers the concrete surface more uniformly. The sodium carboxymethyl cellulose has good water solubility, can form a polymer protective film, has good water retention performance, and can avoid too fast volatilization of surface moisture, thereby being beneficial to moist maintenance of the inside of concrete.

Meanwhile, a layer of curing agent is arranged between the buffer layer and the support layer, so that a water film between the interfaces of the first concrete material and the second concrete material can be formed, and meanwhile, a part of acrylic ester copolymer emulsion in the curing agent is solidified into a film, and the adhesion between the buffer layer and the support layer is utilized to improve the bonding tensile strength.

In a second aspect, embodiments of the present application further provide a support material for high stress soft rock and broken surrounding rock based on deformation control, including a first concrete material and a second concrete material;

The second concrete material comprises 20-60 parts of modified cement, 20-40 parts of admixture, 3-6 parts of curing agent, 5-15 parts of reinforcing fiber, 0.5-1.5 parts of water reducer, 0.01-0.05 part of defoamer, 2-4 parts of thixotropic agent, 80-120 parts of high-strength aggregate and 10-30 parts of water.

In a third aspect, the embodiments of the present application further provide a reference to a supporting construction method for high-stress soft rock and broken surrounding rock based on deformation control, where the supporting construction method may be applied to any one of supporting a coal mine roadway, deep foundation engineering foundation pit supporting, subway roadway wall supporting, foundation supporting of a large or high-rise building, highway roadway and hydraulic tunnel supporting.

Detailed Description

The following describes the technical solutions in the embodiments of the present application.

The specific description is: unless defined otherwise, technical terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The experimental reagents used in the following examples are all conventional biochemical reagents unless otherwise specified; the raw materials, instruments, equipment, etc. used in the following examples are all commercially available or available by existing methods; the dosage of the experimental reagent is the dosage of the reagent in the conventional experimental operation if no special description exists; the experimental methods are conventional methods unless otherwise specified.

The cement in the first concrete material in the embodiment of the application is P.O42.5 cement, and the modified cement in the second concrete material is P.O42.5R rapid hardening silicate cement; the rubber particles are formed by crushing waste natural rubber, and the crushing granularity is 35-40 meshes; the length of the hollow glass fiber tube is 5-15mm, the diameter is 20-50 mu m, and the hollow rate is 30% -60%; the length of the viscose fiber, the polyoxymethylene fiber and the polyester fiber is 5-7mm, and the diameter is 15-20 mu m; polypropylene fiber, polyvinyl alcohol fiber, polyoxymethylene fiber, basalt fiber, sepiolite fiber, steel fiber with the length of 7-8mm and the diameter of 30-60 μm; the granularity of the micro silicon powder is 120-130 meshes, and the silicon dioxide content of the micro silicon powder is more than 95%; the water reducer is a polycarboxylic acid high-performance water reducer, and the water reducing rate is 26.8%; the accelerator is JYS154 accelerator produced by Wuhan Ji Ye L chemical industry Co., ltd; the foaming agent is sodium dodecyl sulfate, and the foaming agent is prepared into nano foam through a nano foam generator. The early strength agent is triethanolamine; curing agent polyol pyruvate (MIPA) aqueous curing agent; the defoaming agent is tributyl phosphate defoaming agent; the high-strength aggregate is quartz sand, and the particle size of the quartz sand is 1.0-1.8mm.

It should be noted that, the excavation of the coal mine roadway tends to cause the redistribution of the original stress of the surrounding rock, and the mechanical behavior of the stress redistribution of the whole surrounding rock can be generalized as the following processes: after three stages of balancing, loosening and collapsing, a new balance is achieved. The "balance" phase: before tunnel excavation, surrounding rock is in a relatively balanced state, and internal stress distribution is relatively stable. During excavation, the original stress of the surrounding rock is damaged and redistributed. A "relaxation" phase: when the roadway begins to excavate, surrounding rock is affected by stress release of the excavated surface, and original stress is gradually reduced, so that deformation pressure is generated. At this stage, the surrounding rock is deformed to some extent, but the surrounding rock as a whole can still be considered to be a continuous medium or a quasi-continuous medium. Stage "loose, collapse": when the tunnel excavation is further deepened, deformation and growth of surrounding rock reach a certain degree, rock blocks and raw rock can be separated, so that collapse or pressure action caused by the dead weight of the rock blocks is caused, and load generated at the stage is called loose pressure, and the load has a certain influence on a supporting structure. That is, during the roadway excavation process, the surrounding rock undergoes a stress redistribution process of three stages of equilibrium, relaxation and relaxation, and collapse. Prior to the equilibration phase, the surrounding rock is in a relatively stable state; in the relaxation stage, deformation pressure mainly influences the stress distribution of surrounding rock; in the loosening and collapse stage, the loosening pressure is mainly caused by deformation and separation, and influences the supporting structure.

Especially, the probability of plastic deformation of soft rock (namely weak surrounding rock) is very high, which often causes the clearance of the roadway to be small, and the normal roadway construction and use are affected. Because of loose geological property structure of the weak surrounding rock and extremely poor stability, the weak surrounding rock is determined to be inevitably deformed to a certain extent in tunnel construction. Due to the fact that the stability of the weak surrounding rock is poor, after a roadway is excavated, the original ground stress balance is destroyed, and therefore the surrounding rock is deformed. That is, the supporting difficulty of the large deformation of the soft rock and the surrounding rock caused by high ground stress is as follows: the surrounding rock after excavation has huge stress, extremely high requirements on the strength and rigidity of the supporting system, and the high ground stress soft rock has large deformation, rapid development and continuous non-convergence, so that the situation of limit invasion caused by poor deformation control of the supporting system after the excavation is very common. Therefore, the special support method has the advantages of simple steps, reasonable design, convenient construction and good use effect, can simply, conveniently and rapidly complete the support construction of high-ground-stress weak surrounding rock and broken surrounding rock roadway, is safe and reliable in construction process, and can effectively control the large deformation of the soft rock.

The first concrete material, the second concrete material and the curing agent provided in the embodiments of the present application will be described in detail.

Preparation example

Preparation example 1

Preparation of a first concrete material: 100 parts of cement, 210 parts of rubber particles, 60 parts of admixture, 10 parts of impervious fiber, 2 parts of accelerator, 3 parts of foaming agent, 3 parts of water reducer, 100 parts of water and 15 parts of early strength agent; uniformly mixing the raw materials to obtain first concrete material mortar; wherein, the impervious fiber consists of glass fiber, viscose fiber, polyoxymethylene fiber and polyester fiber in a weight ratio of 2:3:2:1; the glass fiber is hollow fiber with two closed ends, and the glass fiber is filled with an anti-cracking repair material; the anti-cracking repair material comprises acrylic resin, nano aluminum hydroxy, aluminum potassium sulfate and micro silicon powder in a weight ratio of 2:1:1:1; the admixture consists of mesoporous molecular sieve and zeolite powder in the weight ratio of 2 to 1.

Preparation example 2

Preparation of a first concrete material: 100 parts of cement, 218 parts of rubber particles, 70 parts of admixture, 15 parts of impervious fiber, 3.5 parts of accelerator, 5 parts of foaming agent, 4 parts of water reducer, 110 parts of water and 17.5 parts of early strength agent; uniformly mixing the raw materials to obtain first concrete material mortar; wherein, the impervious fiber consists of glass fiber, viscose fiber, polyoxymethylene fiber and polyester fiber in a weight ratio of 2:3:2:1; the glass fiber is hollow fiber with two closed ends, and the glass fiber is filled with an anti-cracking repair material; the anti-cracking repair material comprises acrylic resin, nano aluminum hydroxy, aluminum potassium sulfate and micro silicon powder in a weight ratio of 2:1:1:1; the admixture consists of mesoporous molecular sieve and zeolite powder in the weight ratio of 3 to 1.

Preparation example 3

Preparation of a first concrete material: 100 parts of cement, 225 parts of rubber particles, 80 parts of admixture, 20 parts of impervious fiber, 5 parts of accelerator, 7 parts of foaming agent, 5 parts of water reducer, 120 parts of water and 20 parts of early strength agent; uniformly mixing the raw materials to obtain first concrete material mortar; wherein, the impervious fiber consists of glass fiber, viscose fiber, polyoxymethylene fiber and polyester fiber in a weight ratio of 2:3:2:1; the glass fiber is hollow fiber with two closed ends, and the glass fiber is filled with an anti-cracking repair material; the anti-cracking repair material comprises acrylic resin, nano aluminum hydroxy, aluminum potassium sulfate and micro silicon powder in a weight ratio of 2:1:1:1; the admixture consists of mesoporous molecular sieve and zeolite powder in the weight ratio of 4 to 1.

Preparation example 4

Preparation of a first concrete material: the difference from preparation example 2 is that the impervious fibers consist of glass fibers, viscose fibers, polyoxymethylene fibers and polyester fibers in a weight ratio of 2:4:4:1.

Preparation example 5

Preparation of a first concrete material: the difference from preparation example 2 is that the impervious fibers consist of glass fibers, viscose fibers, polyoxymethylene fibers and polyester fibers in a weight ratio of 3:4:3:1.

Preparation example 6

Preparation of a first concrete material: the difference from preparation example 2 is that the impervious fibers consist of glass fibers, viscose fibers, polyoxymethylene fibers and polyester fibers in a weight ratio of 4:3:3:1.

Preparation example 7

Preparation of a first concrete material: the difference with the preparation example 2 is that the anti-cracking repair material comprises acrylic resin, nano aluminum hydroxide, aluminum potassium sulfate and micro silicon powder in a weight ratio of 2:2:2:1.

Preparation example 8

Preparation of a first concrete material: the difference with the preparation example 2 is that the anti-cracking repair material comprises acrylic resin, nano aluminum hydroxide, aluminum potassium sulfate and micro silicon powder in a weight ratio of 3:2:2:1.

Comparative example 1

Comparative example 1 also provides a first concrete material, which differs from preparation example 1 in that no rubber particles are added.

Comparative example 2

Comparative example 2 also provides a first concrete material, differing from preparation example 1 in that the barrier fibers consist of viscose, polyoxymethylene and polyester fibers in a weight ratio of 3:2:1.

Comparative example 3

Comparative example 3 also provides a first concrete material, differing from preparation example 1 in that the barrier fibers consist of a 2:1 weight ratio of polyoxymethylene fibers and polyester fibers.

Comparative example 4

Comparative example 4 also provides a first concrete material, which differs from preparation example 1 in that no barrier fiber was added.

Comparative example 5

Comparative example 5 also provides a first concrete material, which is different from preparation example 1 in that the crack-resistant repair material includes nano-sized aluminum hydroxyls, aluminum potassium sulfate and micro silicon powder in a weight ratio of 1:1:1.

Comparative example 6

Comparative example 6 also provides a first concrete material, which is different from preparation example 1 in that the crack-resistant repair material includes aluminum potassium sulfate and silica fume in a weight ratio of 1:1.

Comparative example 7

Comparative example 7 also provides a first concrete material, which is different from preparation example 1 in that the crack-resistant repair material is not added.

The first concrete materials obtained in preparation examples 1 to 8 and comparative examples 1 to 7 were poured into standard cubic test pieces of 150 mm. Times.150 mm and cantilever test pieces of 80 mm. Times.80 mm. Times.1000 mm, respectively, to test compressive strength and damping ratio. According to the specification of GB/T50081-2019 'test method Standard for physical and mechanical properties of concrete', an electrohydraulic servo press is adopted to perform an axial compression test on a 28+28d age standard cube test piece, and the compressive strength of the cube is measured (28+28d compressive strength refers to the compressive strength after the concrete test piece subjected to standard maintenance 28d is prefabricated into a crack and then is maintained for 28d again); and carrying out a free vibration damping test on the cantilever beam test to test the damping ratio of the concrete. The data results of the tests are shown in Table 1.

TABLE 1 detection results of the first concrete materials obtained in preparation examples 1 to 8 and comparative examples 1 to 7

Project	28+28d compressive Strength (MPa)	Damping ratio (%)	Poisson's ratio
				Preparation example 1	3.1	4.52	0.23
Preparation example 2	3.6	4.85	0.31
				Preparation example 3	3.5	4.81	0.28
Preparation example 4	3.8	5.12	0.35
				Preparation example 5	4.2	5.32	0.38
Preparation example 6	4.1	5.28	0.36
				Preparation example 7	3.9	4.88	0.29
Preparation example 8	3.8	4.86	0.30
				Comparative example 1	3.0	3.22	0.15
Comparative example 2	1.8	3.98	0.18
				Comparative example 3	1.6	3.68	0.16
Comparative example 4	1.2	2.25	0.11
				Comparative example 5	2.6	4.52	0.21
Comparative example 6	2.4	4.52	0.21
				Comparative example 7	2.1	4.52	0.21

The poisson ratio of concrete refers to the absolute value μ of the ratio of the transverse positive strain to the axial positive strain when the material is pulled or pressed in one direction, and is also called a transverse denaturation coefficient, which is an elastic constant reflecting the transverse deformation of the material. Within the proportional limits of the material, the absolute value of the ratio of the transverse strain to the corresponding longitudinal strain caused by the uniformly distributed longitudinal stress. The damping ratio of concrete refers to the ratio of the rate of vibration damping due to internal friction and energy loss to the vibration period of the concrete after the concrete is subjected to external force. Generally, the larger the damping ratio, the better the dynamic characteristics of the concrete and the better the damping capacity when subjected to impact or shock loads.

As can be seen from comparing preparation examples 1-8 with comparative examples 1-7 in Table 1, the addition of the particles of the anti-permeability fibers and the rubber provides the first concrete material with a higher damping ratio and Poisson's ratio on the basis of having a better compressive strength, wherein the damping ratio of the first concrete material can reach 5.32% and the Poisson's ratio can reach 0.38. The first concrete material is applied to the support of the roadway, can utilize the high damping performance of the first concrete material to dissipate partial energy generated by the soft surrounding rock, can form a multi-support system with the second concrete material, and reduces the damage and damage degree of the support structure in the roadway support with higher pressure and deformation.

As can be seen from the preparation example 1 and the comparative example 1 in combination with Table 1, the addition of the rubber particles improves the damping ratio of the test piece by 40% as compared with the test piece of the comparative example 1 without the rubber particles. As can be seen from preparation examples 1, 4-6 and comparative examples 2-4 in combination with Table 1, the anti-permeability fibers are prepared from glass fibers, viscose fibers, polyoxymethylene fibers and polyester fibers in a ratio of 2-4:3-4:2-4:1, so that the compressive strength and damping ratio of the test piece can be obviously improved, and the lack of any fiber can cause the reduction of the compressive strength and damping ratio of the test piece. Especially, the glass fiber filled with the anti-crack repairing material is prepared according to examples 2, 7-8 and comparative examples 5-7, the anti-crack repairing material is filled in the glass fiber, when a test piece is cracked due to stress, after the glass fiber is broken by tensile force, the anti-crack repairing material in the glass fiber can be released to the crack, and the acrylic resin, nano aluminum hydroxide, aluminum potassium sulfate and micro silicon powder in the anti-crack repairing material can form firm bonding with the surface of a concrete crack, fill the concrete crack and be tightly connected with surrounding concrete structures, so that the bonding strength is enhanced, and the self-repairing of the concrete crack is realized. The lack of any component in the anti-cracking repair material can greatly reduce the repair effect, and the self-repair effect is better when the weight ratio of the acrylic resin to the nano-hydroxyl aluminum to the aluminum potassium sulfate to the micro-silicon powder is 2-3:1-2:1-2:1.

And through testing, the initial setting time of the second concrete material in the preparation example 2 is 1min50s, the final setting time is 3min30s, the compressive strength of the mortar for 1h is more than 1MPa, and the concrete is suitable for supporting construction of a roadway, so that the construction efficiency is improved. The second concrete material is sprayed on the surface of the to-be-supported body by adopting a spraying construction method and can work together with the surrounding rock of the anchor rod to form a supporting system with enough resistance; the second concrete material can also play roles of timely sealing soft rock and surrounding rock, preventing the soft rock and the surrounding rock from weathering and deliquescing, supporting and filling up reinforced soft rock and surrounding rock, distributing external force and the like.

Preparation example 9

Preparing a second concrete material: the second concrete material comprises 20 parts of modified cement, 20 parts of admixture, 3 parts of curing agent, 5 parts of reinforcing fiber, 0.5 part of water reducer, 0.01 part of defoamer, 2 parts of thixotropic agent and 80 parts of high-strength aggregate; uniformly mixing the raw materials to obtain second concrete material mortar; wherein the admixture consists of mesoporous molecular sieve and zeolite powder in a weight ratio of 2:1; the reinforcing fiber consists of polypropylene fiber and basalt fiber in the weight ratio of 1:2; the thixotropic agent comprises the following components in parts by weight: 2, nano alumina fiber, nano silica fiber and nano carbon fiber.

Preparation example 10

Preparing a second concrete material: the second concrete material comprises 40 parts of modified cement, 30 parts of admixture, 4.5 parts of curing agent, 10 parts of reinforcing fiber, 1 part of water reducer, 0.03 part of defoamer, 3 parts of thixotropic agent and 100 parts of high-strength aggregate; uniformly mixing the raw materials to obtain second concrete material mortar; wherein the admixture consists of mesoporous molecular sieve and zeolite powder in a weight ratio of 3:1; the reinforcing fiber consists of polyvinyl alcohol fiber and sepiolite fiber in the weight ratio of 2:3.5; the thixotropic agent comprises the following components in parts by weight: 4, nano alumina fiber, nano silica fiber and nano carbon fiber.

PREPARATION EXAMPLE 11

Preparing a second concrete material: the second concrete material comprises 60 parts of modified cement, 40 parts of admixture, 6 parts of curing agent, 15 parts of reinforcing fiber, 1.5 parts of water reducer, 0.05 part of defoamer, 4 parts of thixotropic agent and 120 parts of high-strength aggregate; uniformly mixing the raw materials to obtain second concrete material mortar; wherein the admixture consists of mesoporous molecular sieve and zeolite powder in a weight ratio of 4:1; the reinforcing fiber consists of polyoxymethylene fiber and steel fiber in the weight ratio of 3:5; the thixotropic agent comprises the following components in percentage by weight of 0.8:5:5, nano alumina fiber, nano silica fiber and nano carbon fiber.

Preparation example 12

Preparing a second concrete material: unlike preparation 10, the thixotropic agent includes a weight ratio of 0.8:4:3, nano alumina fiber, nano silica fiber and nano carbon fiber.

Preparation example 13

Preparing a second concrete material: unlike preparation 10, the thixotropic agent includes a weight ratio of 0.6:2:3, nano alumina fiber, nano silica fiber and nano carbon fiber.

PREPARATION EXAMPLE 14

Preparing a second concrete material: unlike preparation 10, the thixotropic agent includes a weight ratio of 3.5:4, nano silicon oxide fiber and nano carbon fiber.

Preparation example 15

Preparing a second concrete material: unlike preparation 10, the thixotropic agent was only carbon nanofibers.

PREPARATION EXAMPLE 16

Preparing a second concrete material: unlike preparation example 10, 5 parts of polyacrylate and 2 parts of sodium alginate were added.

Preparation example 17

Preparing a second concrete material: unlike preparation 10, 6.5 parts of polyacrylate and 6 parts of sodium alginate were added.

PREPARATION EXAMPLE 18

Preparing a second concrete material: unlike preparation 10, 8 parts of polyacrylate and 10 parts of sodium alginate were added.

Comparative example 8

Preparing a second concrete material: unlike preparation 10, no thixotropic agent was added.

The mechanical properties of the second concrete materials of preparation examples 9 to 18 and comparative example 8 were carried out in accordance with GB/T50081-2019 "test method for physical mechanical Properties of concrete", and the hardened concrete cubes 28d compressive strength, 28d flexural Strength and 28d tensile Strength were tested. The durability is carried out according to GB/T50081-2009 Standard for test methods for the long-term performance and durability of ordinary concrete, and the main test contents are water permeation resistance, chloride ion permeation resistance and carbonization resistance, wherein the water permeation resistance adopts a water permeation height method, and the chloride ion permeation resistance adopts an electric flux method and an RCM method. The detection results are shown in Table 2.

TABLE 2 detection results of the second concrete materials obtained in PREPARATIVE EXAMPLES 9-18 and COMPARATIVE EXAMPLE 8

As can be seen from preparation examples 9-18, the second concrete material in the embodiment of the present application has high strength and high toughness, and in particular, in preparation example 10, compared with comparative example 8, after the thixotropic agent is added, the mechanical property, elastic modulus, water permeation resistance, chloride ion permeation resistance and carbonization resistance of the second concrete material are obviously improved, and the thixotropic agent improves the thixotropic property of the mortar system, when the mortar system is subjected to shear stress, the viscosity of the mortar system is greatly improved, and the sagging resistance of the mortar during construction is also increased, so that the mortar is easy to construct, and the abrasion coefficient of the mortar is lower, thereby having better abrasion resistance. The 28d compressive strength of the second concrete material can reach 150MPa, which indicates that the second concrete material can bear higher pressure; the 28d flexural strength reaches 38MPa, the 28d tensile strength reaches 9.9MPa, which shows that the second concrete material has higher impact resistance, and the 28d flexural strength reaches 30MPa, which shows that the second concrete material has better flexural resistance. In particular, after the second concrete material exceeds self-bearing stress to generate cracks, the second concrete material can still rely on reinforcing fibers in the second concrete material to effectively prevent the cracks from generating and expanding, and meanwhile, the tensile and shearing resistance of the second concrete material can be maintained. The second concrete material has excellent stress-strain capacity, namely, the second concrete material can support larger initial stress and has excellent deformability, and when the second concrete material is applied to roadway support, the second concrete material can inhibit the deformation or crack aggravation of surrounding rock by being matched with the first concrete material with the strength and the rigidity of the second concrete material. On the other hand, the supporting layer can bear higher pressure not less than 120MPa, and the supporting layer has better crack resistance due to the high-doping amount of reinforcing fibers, so that the supporting layer can be kept in a non-broken state after bearing pressure exceeding self compressive strength, and meanwhile, the generation and the expansion of cracks can be effectively prevented, and the supporting capability is improved.

The second concrete material is applied to the supporting system through spraying construction, so that the construction is quick and efficient, and the supporting strength can be quickly established because the second concrete material has higher early strength (the 2h compressive strength is greater than or equal to 15 MPa).

Preparation example 19

Preparation of curing agent: the curing agent comprises the following components in parts by weight: 7 parts of ethylene-vinyl acetate copolymer, 15 parts of sodium silicate, 25 parts of acrylic ester copolymer emulsion, 2 parts of polyethylene wax, 5 parts of sodium dodecyl benzene sulfonate, 1 part of dodecyl alcohol ester, 10 parts of sodium alkyl naphthalene sulfonate and 15 parts of sodium carboxymethyl cellulose.

Preparation example 20

Preparation of curing agent: the curing agent comprises the following components in parts by weight: 8.5 parts of ethylene-vinyl acetate copolymer, 20 parts of sodium silicate, 27.5 parts of acrylic ester copolymer emulsion, 3.5 parts of polyethylene wax, 7.5 parts of sodium dodecyl benzene sulfonate, 2 parts of dodecyl alcohol ester, 12.5 parts of sodium alkyl naphthalene sulfonate and 17.5 parts of sodium carboxymethyl cellulose.

Preparation example 21

Preparation of curing agent: the curing agent comprises the following components in parts by weight: 10 parts of ethylene-vinyl acetate copolymer, 25 parts of sodium silicate, 30 parts of acrylic ester copolymer emulsion, 5 parts of polyethylene wax, 10 parts of sodium dodecyl benzene sulfonate, 3 parts of dodecyl alcohol ester, 15 parts of sodium alkyl naphthalene sulfonate and 30 parts of sodium carboxymethyl cellulose.

The curing agents obtained in preparation examples 19 to 21 were coated on the first concrete material test piece in preparation example 1, placed in curing boxes at 5 ℃, 25 ℃ and 35 ℃ for 28d, the crack areas of the curing agents were tested, and the concrete coated with the curing agents obtained in preparation examples 19 to 21 did not develop cracks at all three temperatures.

The curing agent obtained in preparation examples 19 to 21 was coated on the first concrete material test piece in preparation example 1, and then the second concrete material was sprayed on the curing agent, and the bonding strength of the interface 28d between the first concrete material and the second concrete material was measured under the condition of wet heat at 80 ℃, and the measurement results are shown in table 3:

TABLE 3 preparation examples 19-21 28d bond Strength of curing agent as bonding interface of first concrete Material and second concrete Material

Project	28d bond Strength (MPa)
		Preparation example 19	3.23
Preparation example 20	3.62
		Preparation example 21	3.55
Blank group	2.13

The blank set in table 3 represents that the surface of the first concrete material test piece was not coated with the curing agent, but the second concrete material was directly sprayed on the surface of the first concrete material test piece. As can be seen from preparation examples 19 to 21 in combination with Table 3, the application of the curing agent significantly improved the adhesive strength between the first concrete material test piece and the second concrete material compared to the uncoated blank.

Example 1

A supporting construction method for high-stress soft rock and broken surrounding rock based on deformation control comprises the following steps:

and constructing anchor rod holes on the surface of the structure to be supported, installing a first reinforcing mesh, and fixing the first reinforcing mesh by using anchor rods.

The surface of the structure to be supported can be any one of a coal mine tunnel surface, a foundation pit surface, a highway tunnel and a hydraulic tunnel. The following is an exemplary illustration of a coal mine roadway surface, but it should be understood that the present application is not limited thereto.

Illustratively, the anchor rod is a screw-thread steel anchor rod, and the specification phi is 0.02 multiplied by 2.00m; one end of the anchor rod is rolled and threaded, the length of the screw thread is 30cm, the depth of the anchor rod hole is 170cm, the anchoring length is 120cm, and the exposed length is 80cm, so that the anchor rod is used for temporary support and can be hung with a first reinforcing mesh.

Exemplary, the supporting main bars of the first reinforcing mesh are made of phi 22 screw thread steel, the longitudinal spacing is 20cm, the distributing bars are made of phi 14 screw thread steel, the circumferential spacing is 25cm, and the stirrups are made ofRound steel, spacing 25cm.

The first concrete material in preparation example 5 was sprayed on the surface of the first reinforcing mat by wet spraying to construct a buffer layer, the thickness of the buffer layer was controlled to 500mm, and the tail end of the anchor rod penetrated out of the buffer layer by about 30mm.

In one possible implementation manner, a layer of curing agent can be sprayed on the surface of the roadway and the surface of the first reinforcing mesh, so that the buffer layer is firmly bonded with the surface of the roadway and the surface of the first reinforcing mesh.

After the initial setting of the buffer layer 5 (1 min50 s), a layer of the curing agent of preparation 20 was sprayed on the surface of the buffer layer 5.

And a second reinforcing mesh is arranged on the surface of the buffer layer through an anchor rod.

Exemplary, the main supporting bars of the second reinforcing mesh are made of phi 22 screw thread steel, the longitudinal spacing is 20cm, the distributing bars are made of phi 14 screw thread steel, the circumferential spacing is 25cm, and the stirrups are made ofRound steel, spacing 25cm.

The second concrete material of preparation example 17 was spray-coated by wet spray method using the second reinforcing mesh as a substrate to construct a supporting layer, the thickness of which was controlled to 200mm. Optionally, the equipment used for the second concrete material spraying operation adopts an ultra-high performance concrete spraying device with an authorization number of CN218437057U for spraying construction.

Then, a layer of the curing agent of preparation example 20 is sprayed on the surface of the supporting layer 8.

In this embodiment, adopted stock and buffer layer effective connection's let pressure preliminary bracing, effectively utilized the bearing capacity of country rock, showing the bearing capacity that improves the preliminary bracing, control the country rock and produce large deformation, the large deformation that the high ground stress soft rock tunnel appears of more effective reply, guarantee construction safety, wet process jet construction is compared in pouring construction moreover, can promote the efficiency of construction effectively. Meanwhile, the buffer layer constructed by the first concrete material in the preparation example 5 has high damping ratio, poisson ratio, high compressibility, high ductility and certain bearing capacity, can absorb deformation energy generated by surrounding rock after the supporting layer is applied under the reaction force provided by the supporting layer, and can generate 100-150cm yielding deformation. Aiming at unpredictable deformation load of a high-ground-stress soft rock stratum, when the primary support is allowed to deform greatly, the buffer layer can generate compression deformation under the support of the support layer, and under the combined action of bonding and connection of cement and impervious fibers, the buffer layer can generate certain compression deformation without cracking, so that the energy generated by the large deformation load of surrounding rock is absorbed, and the support performance of the buffer layer is not affected. Similarly, the second concrete material in preparation example 17 has excellent stress-strain capacity, namely the second concrete material has larger initial stress, excellent deformability and wear resistance, and the wear coefficient is only 1.6; on the other hand, the supporting layer can bear higher pressure not less than 120MPa, and the supporting layer has better crack resistance due to the high-doping amount of reinforcing fibers, so that the supporting layer can be kept in a non-broken state after bearing pressure exceeding self compressive strength, and meanwhile, the generation and the expansion of cracks can be effectively prevented, and the supporting capability is improved.

In the embodiment, the mode of combining deformation leaving, softness before rigidity and support reinforcement is adopted to effectively control the large deformation of the soft rock, ensure the construction safety of the roadway and greatly reduce the construction risk. Meanwhile, the buffer layer and the support layer are constructed in a wet spraying concrete mode in construction, the buffer layer realizes the effect of resisting partial deformation pressure while ensuring the construction efficiency, and the support layer realizes the reinforcing effect thereof, so that a system is formed together to control the roadway large deformation support system, and the soft rock large deformation is further effectively controlled.

After the roadway support structure is finished, monitoring parameters of vault settlement value and peripheral convergence value in the roadway according to GB/T35056-2008 coal mine roadway anchor bolt support technical specifications, wherein all the parameters are qualified after monitoring without obvious change within three months. Specifically, the maximum value of the vault settlement of the roadway is 220.1mm, the minimum value of the vault settlement of the roadway is 34.3mm, and the average value of the vault settlement of the roadway is 123.3mm. The vault settlement values are mainly concentrated between 100mm and 200 mm. The maximum value of the tunnel periphery convergence is 211.7mm, the minimum value of the tunnel periphery convergence is 32.5mm, the average value of the tunnel periphery convergence is 101.8mm, and the tunnel periphery convergence value is mainly concentrated between 100mm and 200 mm.

The implementation principle of the supporting construction method for high-stress soft rock and broken surrounding rock based on deformation control disclosed by the embodiment of the application is as follows: the double-layer reinforcement mesh structure can effectively improve the stability of support and enhance the bearing capacity of surrounding rocks. The double-layer reinforcing steel bar net and the anchor rod structure provide base support for the structures of the buffer layer and the supporting layer, and the buffer layer formed by the first concrete material has enough flexibility to bear large deformation generated by the expansion type soft rock and the high ground stress soft rock so as to convert the expansion energy and the deformation energy of the buffer layer, and also has enough large strength in a specific time period so as to control destructive deformation of the expansion type soft rock and the high ground stress soft rock so as to meet the supporting safety and reliability, and has economic benefit. The buffer layer is matched with the supporting layer formed by the second concrete material to form a combined support, and the buffer layer can well release the deformation energy and the expansion pressure of surrounding rock, so that the stress of the supporting layer is greatly reduced, and the reliability of the supporting structure is improved. Meanwhile, the first concrete material and the second concrete material are both constructed by adopting an injection method, and the first concrete material can be coagulated and solidified in a shorter time to form higher strength, so that the construction method has higher construction efficiency; the second concrete material has high strength and high toughness, and is matched with spraying construction operation, so that the application range is wider, construction can be performed under various complex working conditions, and the construction method has better support stability under the condition of having construction efficiency.

Finally, the above embodiments are only used to illustrate the technical solutions of the present application. It will be appreciated by those skilled in the art that, although the present application has been described in detail with reference to the foregoing embodiments, various modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof. Such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. The supporting construction method for high-stress soft rock and broken surrounding rock based on deformation control is characterized by comprising the following steps of:

spraying a layer of curing agent on the surface of the supporting layer;

2. The support construction method according to claim 1, wherein the admixture in the first concrete material and the second concrete material is composed of mesoporous molecular sieve and zeolite powder in a weight ratio of 2-4:1.

3. The support construction method according to claim 1, wherein the reinforcing fibers comprise organic fibers and inorganic fibers in a weight ratio of 1-3:2-5.

4. A support construction method according to claim 3, wherein the organic fibres are selected from at least one of polypropylene fibres, polyvinyl alcohol fibres, and polyoxymethylene fibres.

5. A support construction method according to claim 3, wherein the inorganic fibres are selected from at least one of basalt fibres, sepiolite fibres, steel fibres.

6. The support construction method according to claim 1, wherein the thixotropic agent comprises a weight ratio of 0.2-0.8:2-5:2-5, nano alumina fiber, nano silicon oxide fiber and nano carbon fiber.

7. The method according to claim 1, wherein the second concrete material further comprises 5-8 parts of polyacrylate and 2-10 parts of sodium alginate.

8. The support construction method according to any one of claims 1 to 7, wherein the curing agent comprises the following components in parts by weight: 7-10 parts of ethylene-vinyl acetate copolymer, 15-25 parts of sodium silicate, 25-30 parts of acrylic ester copolymer emulsion, 2-5 parts of polyethylene wax, 5-10 parts of sodium dodecyl benzene sulfonate, 1-3 parts of dodecyl alcohol ester, 10-15 parts of sodium alkyl naphthalene sulfonate and 15-30 parts of sodium carboxymethyl cellulose.

9. The supporting material for the high-stress soft rock and the broken surrounding rock based on the deformation control is characterized by comprising a first concrete material and a second concrete material;

10. The use of the support construction method according to any one of claims 1 to 7, wherein the support construction method is applicable to any one of a support for a coal mine tunnel, a foundation pit support for a deep foundation engineering, a wall support for a subway tunnel, a foundation support for a large or high-rise building, a highway tunnel, and a hydraulic tunnel support.