Modified epoxy grouting material as well as preparation method and application thereof
By modifying epoxy grouting materials and construction methods, the problem of seepage channels caused by dam foundation fault repair materials was solved, the seepage prevention performance and mechanical properties of the dam were improved, and the safety and construction effect of the hydropower station were achieved.
Patent Information
- Application Number
- CN202511225953.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-29
- Publication Date
- 2025-10-31
AI Technical Summary
Existing dam foundation fault repair materials are prone to causing stress cracks in the dam body to form seepage channels after the hydropower station impounds water, resulting in large repair costs and poor results.
Modified epoxy grouting material is used, which synthesizes a liquid amine adduct by reacting m-phenylenediamine with a monocyclic epoxy compound, and then modifies it with organic acid salts to form a metal ion chelate bridge cross-linking structure. Combined with expanding monomers, this forms a linear structure during epoxy curing, reducing shrinkage and improving toughness. The construction method involves first wet-ground fine cement grouting, followed by high-pressure penetration injection of the modified epoxy grouting material.
It improved the seepage prevention performance and overall mechanical properties of the fault, with the deformation modulus of the fault zone reaching over 5 GPa. This solved the problem of seepage channels formed by stress cracks in the dam body, and enhanced the safety and construction efficiency of the hydropower station.
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Figure CN120865673A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water conservancy construction materials technology, specifically to a modified epoxy grouting material, its preparation method, and its application. Background Technology
[0002] During the construction of the hydropower station's dam, geological defects such as fault fracture zones of varying sizes exist within the dam foundation area, including mud-bearing interlayers that are easily softened by water, with deformation moduli generally ranging from 0.2 to 1.0 GPa. As a building foundation, these will undergo compressive and shear deformation under stress, which is extremely detrimental to the stress transfer of the building foundation. To ensure the safe operation of the hydropower station during water storage, appropriate repair materials and construction techniques should be used when carrying out comprehensive consolidation and seepage prevention treatment on the dam foundation faults.
[0003] Existing dam foundation fault repair materials mostly use inorganic high-strength cement mortar or ordinary cement grouting materials for filling construction. However, after the hydropower station impounds water and is subjected to stress, the small cracks and tiny cavities in the fault structure rock and mud-bearing interlayer of the dam foundation cannot be completely filled. After a long period of operation, the foundation surface of the dam foundation will undergo severe deformation, causing stress cracks in the dam body and thus forming seepage channels. The repair of hydropower stations requires a large investment and the effect is not good.
[0004] Therefore, the current dam foundation fault repair materials applied to dam foundations are prone to causing stress cracks in the dam body, which can lead to seepage channels and result in large investment in hydropower station repairs. Summary of the Invention
[0005] Given that current dam foundation fault repair materials, when applied to dam foundations, easily cause stress cracks in the dam body, thus forming seepage channels, the purpose of this invention is to provide a modified epoxy grouting material, its preparation method, and its application. This modified epoxy grouting material has good bonding effect with concrete, and also has low shrinkage, excellent mechanical properties, and good chemical stability, thus solving the problem that current dam foundation fault repair materials, when applied to dam foundations, easily cause stress cracks in the dam body, thus forming seepage channels.
[0006] This invention is achieved through the following technical solution: In a first aspect, this application provides a modified epoxy grouting material, comprising component A and component B, wherein the mass ratio of component A to component B is (4~6):1; Component A, by weight fraction, includes 90-110 parts of low-viscosity epoxy resin, 25-40 parts of reactive diluent, 13-17 parts of low-viscosity toughening agent, 12-15 parts of hydroxyl-terminated liquid nitrile rubber, 11-14 parts of expanding monomer, and 2-7 parts of silane coupling agent. Component B, by weight fraction, includes 35-45 parts of modified m-phenylenediamine curing agent and 8-10 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent.
[0007] Furthermore, the active diluent includes any one of butylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and butyl glycidyl ether.
[0008] Furthermore, the expanding monomer is a bicyclic lactone, such as bicyclic bis(γ-lactone). During epoxy curing, the bicyclic lactone can participate in the reaction and generate a linear structure from the cyclic structure, resulting in volume expansion and further offsetting the shrinkage of the material.
[0009] Furthermore, the modification method of the modified m-phenylenediamine curing agent is as follows: m-phenylenediamine is synthesized and reacted with a monocyclic epoxy compound to generate a liquid amine adduct, and then an organic acid salt is used to modify the liquid amine adduct to form a metal ion chelate bridge cross-linking structure between macromolecules, and benzyl alcohol groups are introduced on the main chain.
[0010] These modifications have a significant effect on reducing the shrinkage of epoxy curing and improving the toughness of the cured product. Furthermore, their reaction time is relatively long and the curing heat is low, allowing the grouting material to be mixed in large quantities without causing explosive polymerization.
[0011] Secondly, this application provides a method for preparing a modified epoxy grouting material, comprising the following steps: Weigh out the low-viscosity epoxy resin, reactive diluent, low-viscosity toughening agent, hydroxyl-terminated liquid nitrile rubber, expanding monomer, and silane coupling agent in proportion and mix them to obtain component A; Weigh out the modified m-phenylenediamine curing agent and the 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent according to the proportion and mix them to obtain component B; The modified epoxy slurry material is obtained by mixing component A and component B in a certain proportion.
[0012] Thirdly, this application provides an application of the above-mentioned modified epoxy grouting material or the modified epoxy grouting material prepared by the above-mentioned preparation method, including its use in the construction of hydropower station dams.
[0013] Fourthly, this application provides a method for constructing composite grouting for dam foundation faults, which involves first grouting with wet-ground fine cement, and then grouting with the modified epoxy grouting material described above or the modified epoxy grouting material prepared by the above preparation method.
[0014] First, wet-ground fine cement grouting was used to increase the permeability and fluidity of the cement grout in the fine voids and microcavities within the fault, thereby improving its bonding performance with the concrete substrate. Then, modified epoxy grouting material was used for grouting. Under high pressure, the epoxy chemical grout was used to impregnate and penetrate the loose and semi-loose fault structural rocks and muddy interlayers for a long time. The mechanical properties of the drilled static elastic modulus and core samples after grouting showed that the deformation modulus of the fault zone could reach more than 5 GPa, the deformation modulus of the affected zone was greater than 12 GPa, and other mechanical properties also increased accordingly. The seepage prevention performance and overall mechanical properties of the fault were greatly improved.
[0015] Furthermore, the aforementioned method for constructing composite grouting in dam foundation faults specifically includes the following steps: The layout of borehole locations and borehole pipes: The existing working face is achieved through the construction of drainage construction by setting up water collection wells at three points in the deep foundation pit, the rapid on-site solidification of silt into rock, and the on-site removal of silt.
[0016] The grouting holes were divided into zones and sections, and the drilling sections for the grouting holes were divided into six smaller areas based on the original two units. The principle of "first the two ends and then the middle, first the periphery and then the interior" was adopted. The first two areas of the two units were grouted with wet fine cement first, and then the subsequent areas were grouted with wet fine cement in a skip-zone manner. After the strength of the wet fine cement grout reached the design requirements and the inspection holes of the corresponding parts were completed, the epoxy chemical grouting construction was carried out, first sealing the periphery and then implementing the interior.
[0017] Pilot borehole construction: By using panoramic images and sonic detection of the pilot borehole, the strike and location of the fault are determined by comparing the detection results with the original core sample. Simultaneously, the borehole layout, azimuth, inclination, and depth of subsequent production boreholes are verified and adjusted.
[0018] First, wet-ground fine cement grout is used, followed by modified epoxy grouting material. Wet-ground fine cement grouting involves drilling a borehole pipe 2m into the bedrock using an XY-2PC geological drilling rig with ∅89 casing. Then, a 0.5:1 cement grout is used to anchor the embedded borehole pipe. Subsequently, boreholes are drilled in sections from top to bottom, and pressure water tests are conducted in each section. Grouting is performed in sections with internal circulation, and borehole sealers and grout stoppers are installed in each section for internal circulation grouting. Modified epoxy grouting is achieved by using an XY-2PC geological drilling rig with a ∅76 casing to sweep away the original borehole opening pipe and the sealing cement grout stones in the original wet-ground cement grouting hole from top to bottom. Then, a bottom-up, segmented grouting method is adopted, with water pressure tests conducted in each segment. The pure pressure grouting method is carried out in two phases. The grouting process follows the principle of "low pressure, slow grouting, and full penetration". The chemical grouting grout mix ratio is A:B=4.5:1, 5:1, and 6:1 (weight ratio) and is injected at different time periods.
[0019] After grouting is completed, the modified epoxy grouting inspection hole is constructed: by using panoramic images and sonic detection of the inspection hole, the results are compared with the actual core samples to determine whether the epoxy grouting results meet the design requirements, and at the same time, it is verified whether the epoxy grouting is full and whether the strength meets the standards.
[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The curing agent in the modified epoxy grouting material of the present invention is synthesized by reacting m-phenylenediamine with a monocyclic epoxy compound to generate a liquid amine adduct; then modified with an organic acid salt to form a metal ion chelate bridge cross-linking structure between macromolecules, and introduce benzyl alcohol groups on the main chain. These modifications have significant effects on reducing the shrinkage of epoxy curing and improving the toughness of the cured product. At the same time, the reaction time is long and the curing reaction heat is low, so that the grouting material can be mixed in large quantities without bursting. The expanding monomer is a bicyclic lactone. During the epoxy curing process, the bicyclic lactone can participate in the reaction and generate a linear structure from the cyclic structure, resulting in volume expansion, which further offsets the shrinkage of the material.
[0021] (2) The construction method of the present invention using modified epoxy grouting material firstly uses wet-ground fine cement grouting. The fine cement is made by grinding P.O42.5 ordinary Portland cement into fine powder using a complete set of wet grinding equipment. The wet-ground fine cement has a maximum particle size Dmax≤40μm and D50=8~12μm of more than 95% of the cement particles, which increases the permeability and fluidity of the cement grout in the fine voids and micro cavities in the fault, and improves the bonding performance with the concrete base surface. Then, epoxy chemical grouting is used. After the rock mass of the fault is grouted with wet-ground fine cement, the epoxy chemical grout is impregnated and penetrated for a long time under high pressure. The loose and semi-loose fault structural rock and muddy interlayers are treated. The mechanical properties of the borehole static elastic modulus and core samples after grouting show that the deformation modulus of the fault zone can reach more than 5GPa, the deformation modulus of the affected zone is greater than 12GPa, and other mechanical properties are also increased accordingly. The seepage prevention performance and overall mechanical properties of the fault are greatly improved, meeting the design requirements and having strong practicality. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a diagram showing the on-site layout of the F2 fault pilot hole and production hole in this invention; Figure 2 This is a flowchart of the "bottom-up" composite grouting construction process for the pilot hole in this invention; Figure 3 This is a flowchart of the "composite grouting - orifice sealing, segmented grouting from top to bottom" process for producing holes in this invention. Figure 4 This is a diagram showing the on-site layout of the F2 fault inspection hole in this invention. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. The illustrative embodiments and descriptions of this invention are only used to explain this invention and are not intended to limit this invention.
[0024] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known materials or methods have not been specifically described in order to avoid obscuring the invention.
[0025] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples.
[0026] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0027] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.
[0028] Example 1 This embodiment provides a method for preparing a modified epoxy grouting material, the raw material composition of which is: Component A: 100 parts low viscosity epoxy resin, 35 parts butanediol diglycidyl ether, 15 parts epoxy resin active toughening agent, 12 parts hydroxyl-terminated liquid nitrile rubber, 11 parts bicyclobis(γ-lactone), and 2 parts γ-aminopropyltriethoxysilane. Component B: 40 parts of modified m-phenylenediamine curing agent, 10 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent; Component A:Component B = 5:1.
[0029] The modification method of the modified m-phenylenediamine curing agent is as follows: m-phenylenediamine is synthesized and reacted with a monocyclic epoxy compound to generate a liquid amine adduct. Then, an organic acid salt is used to modify the liquid amine adduct to form a metal ion chelate bridge cross-linking structure between macromolecules, and benzyl alcohol groups are introduced on the main chain.
[0030] The specific preparation method is as follows: S1. Weigh 100g of low-viscosity epoxy resin, 35g of butanediol diglycidyl ether, 15g of epoxy resin active toughening agent, 12g of hydroxyl-terminated liquid nitrile rubber, 11g of bicyclobis(γ-lactone), and 2g of γ-aminopropyltriethoxysilane and mix them to obtain component A. S2. Weigh 40g of modified m-phenylenediamine curing agent and 10g of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent and mix them to obtain component B; S3. Mix component A and component B in a 5:1 ratio to obtain the modified epoxy slurry material.
[0031] Example 2 This embodiment provides a method for preparing a modified epoxy grouting material. Unlike Embodiment 1, the amount of raw material components used in this embodiment is different, and the raw material composition is as follows: Component A: 110 parts low viscosity epoxy resin, 40 parts butanediol diglycidyl ether, 17 parts epoxy resin active toughening agent, 15 parts hydroxyl-terminated liquid nitrile rubber, 13 parts bicyclobis(γ-lactone), and 5 parts γ-aminopropyltriethoxysilane. Component B: 35 parts of modified m-phenylenediamine curing agent, 8 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent; Component A:Component B = 6:1.
[0032] Example 3 This embodiment provides a method for preparing a modified epoxy grouting material. Unlike Embodiment 1, the amount of raw material components used in this embodiment is different, and the raw material composition is as follows: Component A: 90 parts low viscosity epoxy resin, 25 parts butanediol diglycidyl ether, 13 parts epoxy resin active toughening agent, 13 parts hydroxyl-terminated liquid nitrile rubber, 12 parts bicyclobis(γ-lactone), and 5 parts γ-aminopropyltriethoxysilane. Component B: 45 parts of modified m-phenylenediamine curing agent, 10 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent; Component A:Component B = 4:1.
[0033] Example 4 This embodiment provides a method for preparing a modified epoxy grouting material. Unlike Embodiment 1, the amount of raw material components used in this embodiment is different, and the raw material composition is as follows: Component A: 100 parts low viscosity epoxy resin, 30 parts butanediol diglycidyl ether, 16 parts epoxy resin active toughening agent, 15 parts hydroxyl-terminated liquid nitrile rubber, 14 parts bicyclobis(γ-lactone), and 7 parts γ-aminopropyltriethoxysilane. Component B: 40 parts of modified m-phenylenediamine curing agent, 8 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent; Component A:Component B = 4.5:1.
[0034] Comparative Example 1 This comparative example provides a method for preparing a modified epoxy grouting material. Unlike Example 4, component A in this comparative example does not contain component B, and its raw material composition is as follows: Its raw material composition is as follows: Component A: 100 parts low-viscosity epoxy resin, 30 parts butanediol diglycidyl ether, 16 parts epoxy resin active toughening agent, 15 parts hydroxyl-terminated liquid nitrile rubber, 14 parts bicyclobis(γ-lactone), and 7 parts γ-aminopropyltriethoxysilane.
[0035] Comparative Example 2 This comparative example provides a method for preparing a modified epoxy grouting material. Unlike Example 4, component B of this comparative example does not contain a modified m-phenylenediamine curing agent. Its raw material composition is as follows: Component A: 100 parts low viscosity epoxy resin, 30 parts butanediol diglycidyl ether, 16 parts epoxy resin active toughening agent, 15 parts hydroxyl-terminated liquid nitrile rubber, 14 parts bicyclobis(γ-lactone), and 7 parts γ-aminopropyltriethoxysilane. Component B: 8 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent; Component A:Component B = 4.5:1.
[0036] The performance of the modified epoxy grouting materials prepared in Examples 1-4 and Comparative Examples 1-2 was tested, and the test results are shown in Table 1.
[0037] Table 1
[0038] Example 5 This embodiment provides a method for constructing a composite grouting layer for dam foundation faults, utilizing the modified epoxy grouting material from Embodiment 4. The specific construction method is as follows: S1. Deep foundation pit dewatering construction A three-point layout of collection wells for dewatering was adopted to quickly isolate the silt from internal and external water inflows, creating dry-land operations and improving the speed of dredging. The internal and external water inflows at the site can be categorized into three types: Scenario 1: water from the conventional concrete pouring and curing process on the dam; Scenario 2: constant flow water from the consolidation and curtain grouting within the left and right dam abutments and galleries; Scenario 3: natural rainfall and seepage water from the foundation surface in front of the dam. Based on the site conditions and after careful study, considering the characteristics of the silt and the working face in areas with concentrated internal and external water inflows, a three-dimensional dewatering method was adopted, from both banks to the middle: dewatering wells → collection wells around the bottom of the foundation pit → drainage ditches and sedimentation tanks around the ground.
[0039] S2. Construction of rapid on-site solidification of silt into rock and on-site silt removal. The process utilizes a powdered solidifying agent and 42.5 bulk cement, delivered by high-pressure gas. The cement is sprayed through gaps created by the rotating mixing blades and evenly distributed across the entire gap track surface as the blades rotate, thus mixing with the in-situ foundation soil. The powdered solidifying agent, adapted to local conditions, primarily uses agricultural crop straw ash from the plateau region and coal gangue from the coal industry. Under the combined action of alkaline and sulfur-based activators, a chemical reaction occurs, accelerating the sludge solidification rate. The straw and thickener in the powdered solidifying agent further accelerate the sludge solidification speed by increasing the sludge's resistance to deformation and its viscosity.
[0040] Due to limitations in on-site hoisting conditions, the arch dam slopes downstream, making it impossible for the 300,000-ton cable crane used for pouring concrete on the dam to connect to the inside of the foundation pit. Furthermore, the right bank tower crane only operates for two hours per day, insufficient to meet the intensity requirements for transporting silt from the foundation pit. Additionally, the permissible horizontal distance between the hoisting working face in front of the dam and the inside of the foundation pit does not meet the maximum safe distance for the truck crane required by the maximum allowable load. This solution utilizes a combination of a small excavator for loading and a double-track climbing material hoist for transporting silt from the deep foundation pit, offering wide applicability and high construction efficiency.
[0041] S3, Dam Foundation Fault Composite Grouting Consolidation and Seepage Prevention Construction A consolidation and seepage prevention curtain grouting zone is set up on site, with five rows of divergent cement-chemical composite grouting. The grouting hole depth is not less than 60m, the grouting pressure at the hole opening is not less than 3.5MPa, and the grouting pressure at the bottom of the hole is not less than 2.5MPa. The grout uses 42.5 grade wet-ground cement followed by epoxy grouting material, with a water-cement ratio of 0.5~3.0. The grouting hole spacing and grouting pressure should be determined based on on-site grouting tests. After grouting, the permeability q≤0.8Lu, the average sound wave velocity of a single hole ≥4000m / s, and the proportion of sound wave velocities less than 3000m / s ≤10%. The consolidation and seepage prevention method adopts a composite grouting method of "concrete overlay layer + five rows of divergent inclined boreholes + wet-ground cement material + epoxy grouting material".
[0042] S3-1. Setting out borehole positions and laying out orifice pipes First, a total station is used to survey and mark the borehole positions in the construction area according to the design requirements. The deviation of the borehole position survey should not exceed 10cm, and a clear mark is set at the surveyed borehole position. Before drilling, the station number, unit number, and borehole number at the unit boundary are marked with red paint at the end of each unit. At the same time, the drilling azimuth and borehole inclination are determined. Then, ∅89 casing is used to drill and embed the borehole casing 2m into the bedrock. Afterward, 0.5:1 cement grout is used to anchor the embedded borehole casing.
[0043] S3-2. Division and Sequence of Grouting Holes and Division of Grouting Hole Drilling Section Length In composite grouting projects, grouting holes are constructed in sequence, with increasing density in each sequence: Wet-ground fine cement grouting (except for pilot holes) is carried out first, with the entire hole grouted from top to bottom in sections, and the cement grouting holes are constructed in two sequences. Epoxy chemical grouting adopts a bottom-up, segmented grouting method, using a pure pressure grouting method, and is constructed in two sequences.
[0044] The initial grouting section is 2m and 3m long, and the subsequent grouting sections are all 5m long. The final hole section is no longer than 6m. At the same time, based on the original two units, six small areas are divided. Following the principle of "first the two ends and then the middle, first the perimeter and then the interior", the first two areas of the two units are grouted with wet fine cement first, and then the subsequent areas are grouted with wet fine cement continuously in a skip-area manner. After the wet fine cement grout reaches the design requirements and the inspection holes of the corresponding parts are completed, the epoxy chemical grouting construction is carried out, first sealing the perimeter and then implementing the interior.
[0045] S3-3, Construction of the pilot hole like Figure 1 and Figure 2 As shown, for the borehole positions after the drilling and grouting section length is divided in step S3-2, the borehole pipe is first drilled into the bedrock 2m deep using an XY-2PC geological drilling rig with ∅89 casing, and then the buried borehole pipe is anchored with 0.5:1 cement grout. Then, a top-down segmented core sampling and bottom-up segmented grouting method was adopted: First, segmented drilling and water pressure testing were carried out to the design depth. Core samples were obtained using a double-casing method (outer casing ∅76, inner casing ∅56) to obtain the rock permeability of each grouting section and the original core samples of each grouting section. Then, grout plugs were used to seal the borehole opening and full-hole pressure water fracture flushing was carried out. Simultaneously, panoramic images and sonic detection of the pilot borehole were carried out. Based on the detection results and the comparison with the original core samples, the strike and location of the fault were determined. Simultaneously, the borehole layout, azimuth, inclination and depth of subsequent production boreholes were verified and adjusted. Then, wet-ground fine cement was used for pilot borehole grouting. After the borehole opening section was grouted, full-hole sealing grouting was carried out. Corresponding inspection records and original core samples were promptly compiled and archived for comparison and verification during subsequent construction.
[0046] S3-4, Wet-ground fine cement grouting like Figure 3As shown, for the boreholes after the drilling and grouting section length is divided in step S3-2, the XY-2PC geological drilling rig with ∅89 casing is first used to drill and embed the borehole pipe 2m into the bedrock. Then, 0.5:1 cement grout is used to anchor the embedded borehole pipe. Then, boreholes are drilled in sections from top to bottom, and water pressure tests are conducted in each section. Grouting is carried out in sections with circulation. Borehole sealers and grout stop plugs are installed in each section for circulation grouting. Before installing the borehole sealer, the hydraulic system and circuit of the grout stop plug and the expansion of the grout stop plug's rubber ball section are checked for normal operation. At the same time, the sealing rings and gaskets of the borehole sealer and grouting pipeline are checked for integrity. Then, the borehole sealer and grouting pipeline are installed. The distance between the grouting pipe opening and the bottom of the hole is ≤50cm to ensure that the grouting pipe can rotate flexibly at low speed and rise and fall appropriately in the center of the borehole sealer during grouting without leakage. Simultaneously, the grout stop plug is pushed in. At the top 50cm of the grouting section, immediately activate the hydraulic pressurization system to expand the grout stop plug and seal the grouting hole wall. During the wet-ground fine cement grouting process, continuously check the sealing of the grout stop plug. If the sealing effect is poor, take appropriate measures promptly until the grout stop plug seals the hole wall. Repeat this drilling and grouting cycle until grouting is complete. When performing wet-ground fine cement grouting, use an automatic grouting recorder (Zhongda Huarui JT-VI type) to record parameters such as grouting pressure, grout injection rate, and grout volume. Table 2 shows the wet-ground cement grout pressure gauge, and Table 3 shows the relationship between grouting pressure and injection rate. In this grouting project, wet-ground fine cement grouting uses four water-cement ratios: 3:1, 2:1, 1:1, 0.7:1, and 0.5:1 (by weight). The wet-ground fine cement grout ratio changes gradually from thin to thick. The principle for changing the grout ratio is as follows: ① The water-cement ratio must not be changed when the grouting pressure remains constant and the injection rate continues to decrease, or when the injection rate remains constant and the pressure continues to increase.
[0047] ② When the injection volume of a certain grade of grout reaches 300L or more or the injection time reaches 30min, and the grouting pressure and injection rate do not change or change only slightly, use a grout with a higher water-cement ratio.
[0048] ③ When the injection rate is greater than 30L / min, the concentration can be increased by stepping up the injection rate as needed.
[0049] ④ During the grouting process, if the grouting pressure or injection rate suddenly changes significantly, the cause should be investigated immediately, and the supervisor should be notified in a timely manner to take appropriate measures.
[0050] Table 2
[0051] Table 3
[0052] During grouting, a designated person should closely monitor the data from the lifting and deformation device, and the grouting pressure and injection rate should be controlled according to the following regulations: (1) When the lifting deformation value is <50μm, the grouting pressure increase process shall be carried out in accordance with the provisions of the table above.
[0053] (2) When the lifting deformation value is 50μm≤lifting value<100μm, the injection rate should be strictly controlled to be less than 10L / min during the grouting pressurization process. If the lifting value no longer increases, the pressurization should be increased step by step; otherwise, the pressurization should be stopped.
[0054] (3) When the lifting deformation value is ≥100μm, stop grouting and wait for 8 hours after solidification before cleaning the hole and re-grouting.
[0055] S3-5, Modified Epoxy Grouting Material Grouting After completing the inspection hole construction in steps S3-4, the corresponding area's epoxy chemical grouting construction begins. First, using an XY-2PC geological drilling rig with a ∅76 casing, the original borehole opening pipe and the sealing cement slurry stones in the original wet-ground cement grouting hole are swept away from top to bottom. Then, a bottom-up, segmented grouting method is adopted, with water pressure tests conducted in each segment. Pure pressure grouting is performed in two sequences. From the bottom of the hole upwards, grout stop plugs are installed in each section, and chemical grouting is carried out alternately for pure pressure grouting within the hole. Before installing the grout stop plug, its hydraulic system and circuit, as well as the expansion of the rubber ball section, are checked for normal operation. Simultaneously, the sealing rings and gaskets of the grouting pipeline are checked for integrity. Then, the grouting pipeline is installed, with the grouting pipe opening ≤50cm from the bottom of the hole, ensuring that the grouting pipe can rotate flexibly at low speed and rise and fall appropriately in time during the grouting process, without grout leakage. Simultaneously, the grout stop plug is pushed into the upper part of the grouting section. At a depth of 50cm, immediately activate the hydraulic pressure boosting system to expand the grout stop plug and seal the grouting hole wall. During the epoxy grouting process, continuously check the sealing performance of the grout stop plug. If the sealing effect is poor, take appropriate measures in time until the grout stop plug seals the hole wall. After removing the water accumulated in the hole using the top grout drainage method, proceed with the epoxy grouting. During epoxy grouting, first fill the grouting section with the hole volume. When the residual water in the hole is discharged through the return grout pipe at the hole opening and the return grout is consistent with the incoming grout, switch to a small-flow chemical grouting pump for grouting. After the epoxy grouting section is completed, replace the residual chemical grout in the hole with cement grout at a ratio of 0.5:1, and then perform grout shielding for 20-30 minutes. The grout shielding pressure is the same as the chemical grouting pressure. After the grout shielding is completed, close the grouting for 4-8 hours, and then raise a section for grouting until the end. Repeat this cycle of drilling and grouting until the grouting is completed.
[0056] Grouting was performed using the modified grouting material prepared in Example 4. During chemical grouting, the chemical grout in the grouting tank was weighed periodically using an electronic scale. The grout injection rate was calculated by converting the smaller grout mass within a time period into the grout injection volume. The grouting pressure was controlled by a pressure gauge at the orifice. The grouting process (mainly grouting pressure and injection rate) was manually recorded in a timely manner. Grout mixing records and shift handover records were kept during the grouting process. After grouting was completed, the on-site manual records were promptly submitted to the on-site supervising engineer for verification. The mixing ratio of the epoxidized chemical grout and the principle for changing different grouts were selected based on the results of laboratory research. Chemical grouting should follow the principle of "low pressure, slow grouting, and full penetration." The mixing ratio of the chemical grout was A:B = 4.5:1, 5:1, and 6:1 (weight ratio) for grouting at different time periods. The principle for changing different grouts was selected based on the results of laboratory research. The grouting pressure is shown in Table 4.
[0057] Table 4
[0058] This grouting project employs a control method primarily based on injection rate to coordinate the relationship between grouting pressure and injection rate. During chemical grouting, the principle of "long time, slow rate, and achieving a certain injection volume as much as possible" should be followed to effectively control the coordination between grouting pressure and injection rate. Generally, the injection rate should be controlled between 0.05 L / min·m and 0.1 L / min·m. When the injection rate is ≤0.05 L / min·m, the grouting pressure should be appropriately increased (based on the design grouting pressure); when the injection rate is ≥0.1 L / min·m, the grouting pressure should be appropriately decreased (based on the design grouting pressure) or the injection volume should be controlled. Table 5 shows the grouting detection and control standards.
[0059] Table 5
[0060] S3-6 Grouting Completion Criteria A. Wet-ground fine cement grouting (1) When the "top-down" segmented grouting method is used for the production hole, the injection rate of the grouting section is no more than 0.02 L / min•m under the maximum design pressure. Continue grouting for 30 minutes and then the grouting can be stopped.
[0061] (2) When the pilot hole is grouted in segments from bottom to top, the injection rate of the grouting segment should not be greater than 1L / min under the maximum design pressure. After grouting for 30 minutes, the grouting can be stopped.
[0062] (3) If the completion criteria are not met for an extended period, the supervisor and designer should be consulted to jointly study and resolve the issue.
[0063] B. Chemical grouting For chemical grouting, after the injection rate is no more than 0.02 L / min under the maximum design pressure, grouting should continue for 30 minutes, or until the gelation time is reached, at which point grouting can be terminated. For borehole sections with unfavorable geological conditions such as muddy interlayers, the grouting time should be extended until the grout initially sets, and the grouting time should not be less than 48 hours.
[0064] When the injection volume is greater than 100 L / m and the injection rate does not change significantly, the supervisor and designer should be notified to jointly study whether it is necessary to use other grouts for injection.
[0065] S3-7 Construction of Modified Epoxy Grouting Inspection Holes like Figure 4 As shown, after completing the epoxy chemical grouting construction in steps S3-5 and S3-6 in different areas, the construction of inspection holes in the corresponding areas begins. First, the XY-2PC geological drilling rig with ∅89 casing is used to drill into the bedrock to a depth of 2m. Then, the buried wellhead pipe is anchored with 0.5:1 cement grout. Then, a top-down segmented core sampling and bottom-up segmented grouting method was adopted: First, segmented drilling and water pressure testing were carried out to the design depth. Core samples were obtained using a double-casing method (outer casing ∅76, inner casing ∅56) to obtain the rock permeability of each grouting section and the original core samples of each grouting section. Then, grout plugs were used to seal the borehole opening and full-hole pressure water fracture flushing was carried out. At the same time, panoramic images of the inspection borehole and sonic testing were carried out. Based on the test results and the actual core samples, it was determined whether the epoxy chemical grouting results met the design requirements. Then, wet-ground fine cement full-hole sealing grouting was carried out. The corresponding inspection records and original core samples were promptly compiled and archived for comparison and verification in subsequent construction processes.
[0066] This construction method is rationally designed. First, wet-ground fine cement grouting is used. The fine cement is made from P.O42.5 ordinary Portland cement, which is ground using a complete set of wet grinding equipment. The wet-ground fine cement has a maximum particle size Dmax≤40μm and D50=8~12μm for more than 95% of the cement particles, which increases the permeability and fluidity of the cement grout in the fine voids and microcavities within the fault, and improves the bonding performance with the concrete substrate. Then, epoxy chemical grouting is used. After wet-ground fine cement grouting, the rock mass in the fault area is infiltrated and penetrated by epoxy chemical grout under high pressure for a long time. The loose and semi-loose fault structural rock and muddy interlayers are treated. The mechanical properties of the static elastic modulus of the borehole and the core samples after grouting show that the deformation modulus of the fault zone can reach more than 5GPa, the deformation modulus of the affected zone is greater than 12GPa, and other mechanical properties also increase accordingly. The seepage prevention performance and overall mechanical properties of the fault are greatly improved, meeting the design requirements and demonstrating strong practicality.
[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.
Claims
1. A modified epoxy grouting material, characterized in that, It includes component A and component B, wherein the mass ratio of component A to component B is (4~6):1; Component A, by weight fraction, includes 90-110 parts of low-viscosity epoxy resin, 25-40 parts of reactive diluent, 13-17 parts of low-viscosity toughening agent, 12-15 parts of hydroxyl-terminated liquid nitrile rubber, 11-14 parts of expanding monomer, and 2-7 parts of silane coupling agent. Component B, by weight fraction, includes 35-45 parts of modified m-phenylenediamine curing agent and 8-10 parts of 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent.
2. The modified epoxy grouting material according to claim 1, characterized in that, The active diluent includes any one of butylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and butyl glycidyl ether.
3. The modified epoxy grouting material according to claim 1, characterized in that, The expanding monomer is a bicyclic lactone.
4. The modified epoxy grouting material according to claim 1, characterized in that, The modification method of the modified m-phenylenediamine curing agent is as follows: m-phenylenediamine is synthesized and reacted with a monocyclic epoxy compound to generate a liquid amine adduct, and then an organic acid salt is used to modify the liquid amine adduct to form a metal ion chelate bridge cross-linking structure between macromolecules, and benzyl alcohol groups are introduced on the main chain.
5. A method for preparing a modified epoxy grouting material, characterized in that, Includes the following steps: Weigh out the low-viscosity epoxy resin, reactive diluent, low-viscosity toughening agent, hydroxyl-terminated liquid nitrile rubber, expanding monomer, and silane coupling agent in proportion and mix them to obtain component A; Weigh out the modified m-phenylenediamine curing agent and the 2,4,6-tris(dimethylaminomethyl)phenol modified curing agent according to the proportion to obtain component B; The modified epoxy slurry material is obtained by mixing component A and component B in a certain proportion.
6. The application of a modified epoxy grouting material according to any one of claims 1 to 4 or a modified epoxy grouting material prepared by the preparation method according to claim 5, characterized in that, This includes the construction of dams for hydroelectric power stations.
7. A method for constructing composite grouting in dam foundation faults, characterized in that, First, wet-ground fine cement is used for grouting, followed by grouting with the modified epoxy grouting material according to any one of claims 1 to 4 or the modified epoxy grouting material prepared by the preparation method according to claim 5. Specifically, the grouting process includes the following steps: Layout of borehole positions and borehole pipes; The grouting holes are divided into zones and sequences, and the drilling sections for the grouting holes are divided. Pilot hole for construction; First, use wet-ground fine cement to form grout, then use modified epoxy grouting material to form grout. After grouting is completed, construct the modified epoxy grouting inspection hole.
8. The method for constructing a composite grouting system for dam foundation faults according to claim 7, characterized in that, The grouting hole sequence and drilling section length are divided into six small areas based on the original two units. The principle of starting from the two ends and then the middle, and starting from the periphery and then the interior is adopted. The first two areas of the two units are wet-ground cement grouting first, and then the subsequent areas are wet-ground cement grouting continuously in a skip-area manner. After the wet-ground cement grout reaches the required strength and the corresponding inspection hole results are completed, the modified epoxy grouting construction is carried out first, then the periphery is sealed and then the interior is implemented.
9. The method for constructing a composite grouting system for dam foundation faults according to claim 7, characterized in that, Wet grinding fine cement slurry is carried out by drilling a casing into the bedrock using a geological drilling rig, then anchoring the buried casing with cement slurry, and finally drilling in sections from top to bottom, conducting water pressure tests in each section, circulating slurry in each section, and installing wellhead sealers and slurry stop plugs in each section for slurry circulation in the well.
10. The method for constructing a composite grouting system for dam foundation faults according to claim 7, characterized in that, Modified epoxy grouting material is prepared by using a geological drilling rig with a matching casing to sweep away the original borehole opening pipe and the original wet-ground cement grouting hole sealing cement slurry stones from top to bottom, and then using a bottom-up, segmented grouting method.