A method for repairing an underwater expansion joint seal with a cement-based material

Abstract

This invention relates to a method for repairing underwater expansion joint waterproofing using cement-based materials, belonging to the field of hydraulic engineering repair technology. The method involves drilling 1-2 holes along the expansion joint where the waterproofing has been damaged; simultaneously preparing a grout that can rapidly solidify into drifting flocs on-site; mixing the grout on-site; injecting the grout into the downstream hole using a screw pump and a pressurized double-grout injection head; and grouting the front hole with a high-toughness cement-based grouting material, thus forming an expansion joint structure with waterproofing function. The advantages are that it can quickly repair the waterproofing function of expansion joints underwater, restore the underwater waterproofing system of hydraulic structures, and ensure that the expansion joint has a reliable waterproofing function for a long time. This not only shortens the construction period and reduces construction difficulty, but also ensures the durability of the seal and the integrity of the structure. It is suitable for emergency repairs in complex underwater environments and for relatively long-term protection of the waterproofing function of expansion joints.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy engineering repair technology, and in particular relates to a method for repairing underwater expansion joints using cement-based materials. Background Technology

[0002] In water conservancy projects, structures adjacent to water, such as gravity dams, sluice gates, water conveyance tunnels, and retaining walls, must be equipped with expansion joints to prevent water leakage and ensure normal operation. If the water seal is damaged for any reason, leading to leakage, it can seriously endanger the safety of the project.

[0003] Typically, the width of expansion joints in water conservancy projects is 20 to 30 mm. The filling materials include polystyrene boards, asphalt templates, etc., with the aim of adapting to structural deformation by utilizing the elastic deformation of the filling and caulking materials.

[0004] Underwater expansion joints are concealed, making them difficult to locate and repair even if damaged. The direction of leakage after expansion joint damage is very clear: water flows from high head to low head. This is especially problematic when water levels are high, potentially affecting not only the normal operation of the project but also its safety. Therefore, prompt repair is essential. Summary of the Invention

[0005] This invention provides a method for repairing underwater expansion joint waterproofing using cement-based materials. The purpose is to use cement-based materials with high toughness and relatively low elastic modulus to create a novel expansion joint waterproofing structure underwater, thereby quickly repairing the expansion joint waterproofing.

[0006] The technical solution adopted by this invention includes the following steps:

[0007] (1) Drill 1-2 holes along the expansion joint where the water stop is damaged, with a depth 1 meter beyond the depth of the structural foundation surface;

[0008] (2) Prepare slurry A and B on-site, which are driftable flocculants that can quickly solidify and seal the flowing water in the expansion joint. Mix them on-site at a mass ratio of 1:(0.5 to 0.95) to prepare the slurry, and control the slurry diffusion to be greater than 400 mm.

[0009] (3) Grouting is performed in the downstream direction through a screw pump and a booster double-slurry grouting head;

[0010] (4) Use high-toughness cement-based grouting material to grout the front hole until it is filled to form an expansion joint structure with water-stopping function.

[0011] In step (1) of the present invention, double holes are used. If the construction layout is convenient, one hole is drilled 8 to 20 cm downstream and upstream of the damaged expansion joint waterstop. If the layout is inconvenient, two holes are drilled in the downstream direction of the expansion joint at a convenient location, with a distance of L = 20 to 50 cm between the two holes.

[0012] Step (2) of the present invention includes:

[0013] 1) Calculate the time from the feeding trough 1 to the shrinkage outlet 206, and add 20 to 45 seconds to this time as the setting time of the prepared slurry;

[0014] 2) Slurries A and B, which can rapidly coagulate drifting flocs, are prepared simultaneously on-site; wherein:

[0015] i) Prepare a slurry A with the following weight parts of a driftable flocculant that can coagulate rapidly;

[0016] General-purpose Portland cement PO42.5, 1000 parts;

[0017] 200-700 parts of Class II or higher fly ash;

[0018] Silica fume, wherein the SiO2 content is not less than 90%, and the specific surface area is 13,000 m² / kg to 20,000 m² / kg, 2 to 150 parts;

[0019] Cenospheres: 5-550 parts of hollow glass microspheres made from fly ash;

[0020] 10-30 mm short fibers, 1-150 parts;

[0021] Water 200-1460 parts;

[0022] 3-50 parts of polycarboxylate superplasticizer;

[0023] Drag-reducing agent: 1-140 parts of zwitterionic polyacrylamide;

[0024] 1-150 parts of hydroxyethyl cellulose;

[0025] 1-200 parts of hydroxypropyl methylcellulose;

[0026] Add appropriate amounts of various materials to a non-aluminum preparation container and mix until the diffusion degree is not less than 400 mm.

[0027] ii) Prepare a slurry B with the following weight proportions of driftable flocculants that can rapidly coagulate;

[0028] Water glass, 10–45 Bé, modulus 1.5–3.0, 1000 parts

[0029] 200-1060 parts purified water

[0030] The preparation process involves diluting the water glass with pure water in a non-aluminum preparation container. First, pour in the water glass, then slowly add water while stirring.

[0031] iii) When the diffusion of slurries A and B, which can rapidly coagulate driftable flocs, is greater than 400 mm, a specially made feeding trough with a feeding amount control device is installed on the feeding port of the screw pump. The two slurries are fed in proportion in the self-made feeding trough, and the feeding amount is controlled by the controller of the feeding trough. The two slurries are mixed in the screw pump.

[0032] When preparing slurry A, which allows for rapid coagulation of drifting flocs, this invention also includes auxiliary ingredients:

[0033] a) If there are requirements for early strength and later strength, triethanolamine 1-150 parts can be used for adjustment;

[0034] b) If there are requirements for the toughness of the material after solidification, it can be adjusted with 1-12 parts of sodium methylene dinaphthalene sulfonate (NNO), 5-200 parts of acrylic emulsion, or 5-150 parts of waterborne epoxy resin.

[0035] When preparing slurry B, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0036] a) To shorten the setting and curing time of the slurry, add 5-120 parts of sodium hydroxide;

[0037] b) If it is necessary to delay the setting time of the slurry, use any of the following methods:

[0038] ① Add 5-100 parts of liquid inorganic silica gel and 5-50 parts of disodium hydrogen phosphate;

[0039] ② Add 10-300 parts of silica fume and 5-50 parts of disodium hydrogen phosphate.

[0040] If the solidification is too fast, liquid inorganic silica gel and disodium hydrogen phosphate can be added to prolong the solidification time. If the solidification is too slow, sodium hydroxide can be prepared as a solution and then added.

[0041] The feeding trough of the present invention includes a trough body, a central partition, a first feeding port, a second feeding port, a first discharge gate with an opening adjustment valve, a second discharge gate with an opening adjustment valve, and a controller. The central partition divides the trough body into two parts. The upper part of the trough body has a first feeding port and a second feeding port. The bottom discharge gates are respectively equipped with first discharge gates with opening adjustment valves and second discharge gates with opening adjustment valves. The opening adjustment of each discharge gate is completed by the controller.

[0042] Step (3) of the present invention includes:

[0043] 1) Use a screw pump for grouting. Connect the grouting pipe outlet to the polyurethane grouting pump through a pressurized double grouting head. Insert the grouting pipe directly to the bottom of the hole and simultaneously inject grout A and B, which can drift flocs and quickly solidify, and polyurethane grout.

[0044] Preparation of polyurethane slurry:

[0045] 1000 parts of single-component polyurethane;

[0046] Diluent: 50-1100 parts xylene or acetone;

[0047] The injection volume of polyurethane is adjusted by the switch opening of the polyurethane pump at the pressurized double-slurry injection port.

[0048] 2) Observe the water flow at the leak point. When the downstream outlet water flow rate decreases significantly, it indicates that the gap or orifice has been sealed. At this time, grout can be injected directly to the top of the hole to complete the temporary water-stopping operation of the hole.

[0049] The pressurized dual-slurry grouting head of the present invention includes a screw pump connection port one, an opening adjustment valve one, a polyurethane grouting pump connection port one, an opening adjustment valve two, a grouting head body, and a shrinkage grout outlet. The grouting head body has a screw pump connection port one, a polyurethane grouting pump connection port one, and a shrinkage grout outlet. An opening adjustment valve one is located at the screw pump connection port, and an opening adjustment valve two is located at the polyurethane grouting pump connection port one.

[0050] The high-toughness cement-based grouting material in step (4) of this invention is prepared as follows:

[0051] 1) Raw materials comprising the following weight proportions;

[0052] (a) 1000 parts of general-purpose Portland cement PO42.5;

[0053] 200-800 parts water;

[0054] (b) Admixtures

[0055] 3-150 parts of polycarboxylate superplasticizer;

[0056] Drag-reducing agent: 2-140 parts of zwitterionic polyacrylamide;

[0057] 3-350 parts of hydroxypropyl methylcellulose;

[0058] 1-350 parts of hydroxyethyl cellulose;

[0059] Triethanolamine 1-100 parts;

[0060] Sodium methylene dinaphthalene sulfonate (NNO) 1-80 parts;

[0061] 1-200 parts of latex powder;

[0062] 1-250 parts of quick-setting agent;

[0063] (c) Admixtures

[0064] 500-700 parts of fly ash of grade II or above;

[0065] Silica fume, with a SiO2 content of not less than 90% and a specific surface area of ​​13,000 m² / kg to 20,000 m² / kg, and 3 to 150 parts;

[0066] 2-150 parts of 10-30 mm polypropylene fiber;

[0067] (d) Aggregates

[0068] 3-3500 parts of gravel with a particle size of less than 5 mm;

[0069] Medium to coarse sand, 3000-3000 parts;

[0070] 2) Mixing materials

[0071] According to actual requirements, select the material proportions in (a) to (d) for mixing, and control the expansion during grouting to 400-600mm.

[0072] The grouting process in step (4) of this invention is as follows:

[0073] 1) Use a screw pump to inject grout through a double-slurry pressureless grouting pipe. Connect a polyurethane grouting pump 80cm away from the grout outlet of the grouting pipe and inject polyurethane grout at the same time to mix the polyurethane with the cement-based grout.

[0074] Polyurethane grout preparation:

[0075] 2 to 1100 parts of single-component polyurethane;

[0076] Diluent: 1-1100 parts xylene or acetone;

[0077] (2) Grouting is carried out by inserting a buried pipe: first insert the grouting pipe to the bottom, and then grout.

[0078] (3) Start pulling the pipe upwards when the grout has buried the grouting port for about 20cm;

[0079] (4) Grouting continues until the top is sealed, and the expansion joint waterproofing repair is completed.

[0080] The dual-slurry pressureless grouting pipe of the present invention includes a screw pump connection port 2, an opening adjustment valve 3, a grouting pipe body, a polyurethane grouting pump connection port 2, an opening adjustment valve 4, and a grout outlet. The grouting pipe body has a screw pump connection port 1, a polyurethane grouting pump connection port 2, and a grout outlet. An opening adjustment valve 3 is located at the screw pump connection port, and an opening adjustment valve 4 is located at the polyurethane grouting pump connection port 2.

[0081] The advantages of this invention are its ability to quickly repair the waterproofing function of expansion joints in water and restore the underwater waterproofing system of hydraulic structures. It is suitable for rapid repair scenarios after the waterproofing of expansion joints in hydraulic structures has been damaged. Temporary sealing is achieved through a caulking plate between the expansion joints, preventing water flow inside. Subsequently, a high-toughness, low-elasticity, and rapidly setting cement-based waterproofing material forms in still water, and the novel waterproofing structure assumes the subsequent waterproofing function of the expansion joint. Specifically, this involves drilling holes in the upstream and downstream areas of the original expansion joint, or along the expansion joint at a convenient construction location, and grouting through a double-slurry pressurized grouting head. Utilizing the time-limited setting characteristics of cement-based materials, and the loose flocculated state formed after the sudden release of pressure from the pressurized cement-based material, combined with the guiding effect of water flow, the cement-based sealing material with adjustable density and gradually forming flocs is delivered to the gap between the expansion joint and the caulking plate, gradually sealing the gap between them, thereby quickly stopping the leakage problem of the expansion joint.

[0082] This invention first uses targeted filling with flowing water to initially seal the leakage channels of the expansion joint, and then uses a high-strength cement-based material with both elasticity and toughness to construct a new water-stopping structure, thereby ensuring that the expansion joint has a reliable water-stopping function for a long time. This not only shortens the construction period and reduces the construction difficulty, but also ensures the sealing durability and structural integrity. It is suitable for emergency repair in complex underwater environments and relatively long-term guarantee of the water-stopping function of expansion joints.

[0083] This invention utilizes a cement-based material suitable for rapid repair of underwater expansion joint waterproofing. Extensive testing revealed that adding appropriate amounts of latex powder, polypropylene fiber, and polyurethane materials to the cement-based material significantly improves its toughness and effectively reduces its elastic modulus. The resulting high-toughness cement-based material has minimal impact on its resistance to water pressure. This material, used to repair or replace underwater expansion joint waterproofing structures, effectively resists expansion and contraction caused by temperature changes, achieving excellent waterproofing results. When applied to areas above the operating water level, its effectiveness is even better during low-temperature construction. Attached Figure Description

[0084] Figure 1 This is a schematic diagram of the feeding trough of the present invention;

[0085] Figure 2 This is a schematic diagram of the structure of the pressurized double-slurry grouting head of the present invention;

[0086] Figure 3 This is a schematic diagram of the structure of the double-slurry pressureless grouting pipe of the present invention;

[0087] Figure 4 This is a top view of the expansion joint and drilling location of the water-retaining structure of the present invention;

[0088] Figure 5 This is a cross-sectional view of the expansion joint and drilling location of the water-retaining structure of the present invention. Detailed Implementation

[0089] Example 1

[0090] Includes the following steps:

[0091] (1) For example Figure 4 5. Drill two holes along the expansion joint where the water stop is damaged, with a depth 1 meter beyond the depth of the structural foundation surface.

[0092] Using a double-hole design, if the construction layout is convenient, drill one hole 8cm downstream and one hole upstream of the damaged expansion joint waterstop; if the layout is inconvenient, drill two holes downstream of the expansion joint at a convenient location, with a distance of L=20cm between the two holes. After forming a new type of waterstop, it directly replaces the original expansion joint waterstop.

[0093] (2) Prepare on-site slurry A and B, which are driftable flocculants that can quickly solidify and seal flowing water in expansion joints, and mix them on-site at a mass ratio of 1:0.5, controlling the slurry diffusion to be greater than 400mm; including:

[0094] 1) Calculate the time from the feeding trough 1 to the shrinkage outlet 206, and add 20 seconds to this time as the setting time of the prepared slurry;

[0095] 2) Slurries A and B, which can rapidly coagulate drifting flocs, are prepared simultaneously on-site; wherein:

[0096] i) Prepare a slurry A with the following weight parts of a driftable flocculant that can coagulate rapidly;

[0097] General-purpose Portland cement PO42.5, 1000 parts;

[0098] Two portions of Class II or higher fly ash;

[0099] Silica fume, wherein the SiO2 content is not less than 90% and the specific surface area is 13,000 square meters / 2 parts per kilogram;

[0100] Cryopreservation beads: 5 parts of fly ash hollow glass microspheres;

[0101] One part of short fibers, 10-30 mm in diameter;

[0102] 200 parts water;

[0103] Three parts of polycarboxylate superplasticizer, a pale yellow liquid or white powder, with good water solubility, high water reduction rate (25%~40%), low dosage, low shrinkage, comb-type polymer copolymer, with acrylic carbon chain as the main chain and polyoxyethylene ether as the side link, containing active anionic functional groups such as carboxyl groups, used in high-strength concrete, self-leveling mortar, and precast components, significantly reducing the water-cement ratio and improving strength and density;

[0104] Drag reducer: 1 part of zwitterionic polyacrylamide, white powder / granules, easily soluble in water, with strong adsorption bridging and charge neutralization capabilities, resistant to salt, acid and alkali, a high molecular linear water-soluble polymer, the main chain of which is a polyacrylamide carbon chain, containing cationic groups (quaternary ammonium salts, etc.) and anionic groups (carboxyl groups, etc.), used for flocculation of building material mud, dewatering of sludge, water retention and thickening of mortar / concrete, and improvement of workability of mixing materials;

[0105] 1 part hydroxyethyl cellulose;

[0106] 1 part hydroxypropyl methylcellulose;

[0107] Add appropriate amounts of various materials to a non-aluminum preparation container and mix until the diffusion degree is not less than 400 mm.

[0108] ii). Prepare slurry B with the following weight proportions of driftable flocs that can coagulate rapidly; since water quality affects the slurry coagulation process, sometimes by tens of seconds, dilute the water glass with pure water;

[0109] Water glass, 10–45 Bé, modulus 1.5–3.0, 1000 parts

[0110] 200 portions of purified water

[0111] The preparation process involves diluting the water glass with pure water in a non-aluminum preparation container. First, pour in the water glass, then slowly add water while stirring.

[0112] iii) When the diffusion of both driftable flocs A and B is greater than 400 mm, the specially made feeding trough 1 with a feeding amount control device is used. Figure 1 Installed on the feed port of the screw pump, the material is fed into the self-made feed trough 1 according to the ratio. The feeding amount is controlled by the controller of the feed trough. The two slurries are mixed in the screw pump and can be used directly for grouting.

[0113] When preparing slurry A, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0114] a) If there are requirements for early strength and later strength, 1 part of triethanolamine can be used for adjustment;

[0115] b) If there are requirements for the toughness of the material after solidification, it can be adjusted with 1 part NNO, 5 parts acrylic emulsion or 5 parts water-based epoxy resin.

[0116] When preparing slurry B, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0117] a) To shorten the slurry setting and curing time, add 5% sodium hydroxide; reduce the water glass modulus.

[0118] b) If it is necessary to delay the setting time of the slurry, use any of the following methods:

[0119] ① Add 5 parts of liquid inorganic silica gel and 5 parts of disodium hydrogen phosphate;

[0120] ② Add 10 parts silica fume and 5 parts disodium hydrogen phosphate.

[0121] If the solidification is too fast, liquid inorganic silica gel and disodium hydrogen phosphate can be added to prolong the solidification time. If the solidification is too slow, sodium hydroxide can be prepared as a solution and added, which can slow down the solidification process and reduce resistance with the surrounding environment.

[0122] The feeding trough 1 includes a trough body 101, a central partition 102, a feeding port 103, a feeding port 2 104, a discharge gate 105 with an opening adjustment valve, and a discharge gate 2 106 with an opening adjustment valve, as well as a controller. The central partition 102 divides the trough body 101 into two parts. The upper part of the trough body 101 has a feeding port 103 and a feeding port 2 104. The discharge gates 105 and 2 106 with opening adjustment valves are installed at the bottom discharge ports, respectively. The opening adjustment of each discharge gate is completed by the controller.

[0123] (3) Grouting the downstream borehole using a screw pump and a booster double-slurry grouting head; including:

[0124] 1) Grouting is performed using a screw pump. At the outlet of the grouting pipe, a booster double-slurry grouting head 2 is connected to the polyurethane grouting pump (see...). Figure 2 Insert the grouting pipe directly to the bottom of the hole and simultaneously inject grout A and B, which can rapidly solidify drifting flocs, and polyurethane grout. If it is necessary to reduce the amount of polyurethane, diluents such as xylene or acetone can be added for adjustment.

[0125] Preparation of polyurethane slurry:

[0126] 1000 parts of single-component polyurethane;

[0127] Diluent: 50 parts xylene or acetone;

[0128] Polyurethane in pressurized double-slurry injection port ( Figure 2The injection volume of polyurethane can be adjusted using the switch opening of the polyurethane pump. If the injection volume is too small, the opening will be too narrow, making it difficult to control the amount of grout entering the pressurized double grout injection port at the outlet. Diluent can be added to adjust this.

[0129] 2) Observe the water flow at the leak point. When the downstream outlet water flow rate decreases significantly, it indicates that the gap or orifice has been sealed. At this time, grout can be injected directly to the top of the hole to complete the temporary water-stopping operation of the hole.

[0130] The pressurized double-slurry grouting head 2 includes a screw pump connection port 201, an opening adjustment valve 202, a polyurethane grouting pump connection port 203, an opening adjustment valve 204, a grouting head body 205, and a shrinkage grout outlet 206. The grouting head body 205 has a screw pump connection port 201, a polyurethane grouting pump connection port 203, and a shrinkage grout outlet 206. An opening adjustment valve 202 is located at the screw pump connection port 201, and an opening adjustment valve 204 is located at the polyurethane grouting pump connection port 203.

[0131] (4) Grout the front hole with high-toughness cement-based grouting material until it is full. Since the water level does not change significantly in a short time, the grout inside the hole will quickly solidify, forming an expansion joint structure with water-stopping function. Considering that the underwater temperature difference is small, the expansion joint water-stopping material only needs to meet the following requirements to achieve the water-stopping function: it should have sufficient strength to resist water pressure and sufficient toughness to adapt to the temperature stress caused by temperature change. Using high-toughness cement-based materials with relatively low elastic modulus to make a new type of expansion joint water-stopping structure underwater is an effective method to quickly repair the water-stopping function of expansion joints.

[0132] The high-toughness cement-based grouting material is prepared as follows:

[0133] 1) Raw materials comprising the following weight proportions;

[0134] (a) 1000 parts of general-purpose Portland cement PO42.5;

[0135] 200 parts water;

[0136] (b) Admixtures

[0137] 3 parts polycarboxylate superplasticizer;

[0138] Drag reducer: 2 parts zwitterionic polyacrylamide;

[0139] 3 parts hydroxypropyl methylcellulose;

[0140] 1 part hydroxyethyl cellulose;

[0141] One part of triethanolamine;

[0142] 1 part of NNO;

[0143] 1 part latex powder;

[0144] 1 part quick-setting agent (powder);

[0145] (c) Admixtures

[0146] Five portions of fly ash of grade II or above;

[0147] Silica fume, with SiO2 content not less than 90% and specific surface area of ​​13,000 square meters / kg, 3 parts;

[0148] Two parts of 10-30 mm polypropylene fiber;

[0149] (d) Aggregates

[0150] Three portions of gravel with a particle size of less than 5 mm;

[0151] 3 parts medium-coarse sand;

[0152] 2) Mixing materials

[0153] According to actual requirements, select the material proportions from (a) to (d) for mixing, and control the expansion during grouting to 400mm;

[0154] The grouting process into the forward hole is as follows:

[0155] 1) Grouting is performed using a screw pump through a double-slurry pressureless grouting pipe 3. The grouting pipe 303 is connected to a polyurethane grouting pump 80cm from the grout outlet. Figure 3 Simultaneously, polyurethane grout is injected to mix the polyurethane with the cement-based grout. The amount of polyurethane added can be adjusted using a diluent.

[0156] Polyurethane grout preparation:

[0157] Two parts of single-component polyurethane;

[0158] Diluent: 1 part xylene or acetone;

[0159] The dual-screw pressureless grouting pipe 3 includes a screw pump connection port 2 301, an opening adjustment valve 302, a grouting pipe body 303, a polyurethane grouting pump connection port 2 304, an opening adjustment valve 4 305, and a grout outlet 306. The grouting pipe body 303 has a screw pump connection port 1 301, a polyurethane grouting pump connection port 2 304, and a grout outlet 306. An opening adjustment valve 302 is located at the screw pump connection port 1 301, and an opening adjustment valve 4 305 is located at the polyurethane grouting pump connection port 2 304.

[0160] (2) Grouting is carried out by inserting a buried pipe: first insert the grouting pipe to the bottom, and then grout.

[0161] (3) Start pulling the pipe upwards when the grout has buried the grouting port about 20cm deep; at this time, pulling the pipe is not difficult.

[0162] (4) Grouting continues until the top is sealed, and the expansion joint waterproofing repair is completed.

[0163] Example 2

[0164] Includes the following steps:

[0165] (1) Drill two holes along the expansion joint where the waterproofing is damaged, extending 1 meter beyond the foundation surface. Figure 4 , 5 ;

[0166] Using a double-hole method, if the construction layout is convenient, drill one hole 15cm downstream and 15cm upstream of the damaged expansion joint waterstop; if the layout is inconvenient, drill two holes in a convenient location along the downstream direction of the expansion joint, with a distance of L=35cm between the two holes.

[0167] (2) On-site preparation of slurry A and B, which are driftable flocculants that rapidly solidify to quickly seal flowing water in expansion joints, and on-site mixing and preparation of slurry at a mass ratio of 1:0.75, controlling the slurry diffusion to be greater than 400mm; including:

[0168] 1) Calculate the time from the feeding trough 1 to the shrinkage outlet 206, and add 32 seconds to this time as the setting time of the prepared slurry;

[0169] 2) Slurries A and B, which can rapidly coagulate drifting flocs, are prepared simultaneously on-site; wherein:

[0170] i) Prepare a slurry A with the following weight parts of a driftable flocculant that can coagulate rapidly;

[0171] General-purpose Portland cement PO42.5, 1000 parts;

[0172] 350 portions of fly ash of grade II or above;

[0173] Silica fume, wherein the SiO2 content is not less than 90%, the specific surface area is 16,000 square meters / kg, 75 parts;

[0174] Cryopreservation beads: 280 parts of hollow glass microspheres made from fly ash;

[0175] 75 parts of short fibers, 10-30 mm in diameter;

[0176] 850 portions of water;

[0177] 26 parts of polycarboxylate superplasticizer;

[0178] Drag-reducing agent: 70 parts of zwitterionic polyacrylamide;

[0179] 75 parts of hydroxyethyl cellulose;

[0180] 100 parts of hydroxypropyl methylcellulose;

[0181] Add appropriate amounts of various materials to a non-aluminum preparation container and mix until the diffusion degree is not less than 400 mm.

[0182] ii). Prepare slurry B with the following weight proportions of driftable flocs that can coagulate rapidly; since water quality affects the slurry coagulation process, sometimes by tens of seconds, dilute the water glass with pure water;

[0183] Water glass, 10–45 Bé, modulus 1.5–3.0, 1000 parts

[0184] 600 portions of purified water

[0185] The preparation process involves diluting the water glass with pure water in a non-aluminum preparation container. First, pour in the water glass, then slowly add water while stirring.

[0186] iii) When the diffusion of both driftable flocs A and B is greater than 400 mm, the specially made feeding trough 1 with a feeding amount control device is used. Figure 1 Installed on the feed port of the screw pump, the material is fed into the self-made feed trough 1 according to the ratio. The feeding amount is controlled by the controller of the feed trough. The two slurries are mixed in the screw pump and can be used directly for grouting.

[0187] When preparing slurry A, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0188] a) If there are requirements for early strength and later strength, 75 parts of triethanolamine can be used for adjustment;

[0189] b) If the toughness of the material after solidification is required, it can be adjusted with 6 parts of sodium methylene dinaphthalene sulfonate (NNO), 100 parts of acrylic emulsion, or 75 parts of waterborne epoxy resin.

[0190] When preparing slurry B, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0191] a) To shorten the setting and curing time of the slurry, add 60 parts of sodium hydroxide;

[0192] b) If it is necessary to delay the setting time of the slurry, use any of the following methods:

[0193] ① Add 50 parts of liquid inorganic silica gel and 25 parts of disodium hydrogen phosphate;

[0194] ② Add 150 parts silica fume and 25 parts disodium hydrogen phosphate;

[0195] If the solidification is too fast, liquid inorganic silica gel and disodium hydrogen phosphate can be added to prolong the solidification time. If the solidification is too slow, sodium hydroxide can be prepared as a solution and then added.

[0196] The feeding trough 1 includes a trough body 101, a central partition 102, a feeding port 103, a feeding port 2 104, a discharge gate 105 with an opening adjustment valve, and a discharge gate 2 106 with an opening adjustment valve, as well as a controller. The central partition 102 divides the trough body 101 into two parts. The upper part of the trough body 101 has a feeding port 103 and a feeding port 2 104. The discharge gates 105 and 2 106 with opening adjustment valves are installed at the bottom discharge ports, respectively. The opening adjustment of each discharge gate is completed by the controller.

[0197] (3) Grouting the downstream borehole using a screw pump and a booster double-slurry grouting head; including:

[0198] 1) Grouting is performed using a screw pump. At the outlet of the grouting pipe, a booster double-slurry grouting head 2 is connected to the polyurethane grouting pump (see...). Figure 2 Insert the grouting pipe directly to the bottom of the hole and simultaneously inject grout A and B, which can drift and flocculate rapidly, and polyurethane grout.

[0199] Preparation of polyurethane slurry:

[0200] 1000 parts of single-component polyurethane;

[0201] Diluent: 550 parts xylene or acetone;

[0202] Polyurethane in pressurized double-slurry injection port ( Figure 2 The injection volume of polyurethane is adjusted using the switch opening of the polyurethane pump;

[0203] 2) Observe the water flow at the leak point. When the downstream outlet water flow rate decreases significantly, it indicates that the gap or orifice has been sealed. At this time, grout can be injected directly to the top of the hole to complete the temporary water-stopping operation of the hole.

[0204] The pressurized double-slurry grouting head 2 includes a screw pump connection port 201, an opening adjustment valve 202, a polyurethane grouting pump connection port 203, an opening adjustment valve 204, a grouting head body 205, and a shrinkage grout outlet 206. The grouting head body 205 has a screw pump connection port 201, a polyurethane grouting pump connection port 203, and a shrinkage grout outlet 206. An opening adjustment valve 202 is located at the screw pump connection port 201, and an opening adjustment valve 204 is located at the polyurethane grouting pump connection port 203.

[0205] (4) Use high-toughness cement-based grouting material to grout the front hole until the front hole is full. Since the water level does not change significantly in a short time, the grout in the hole will quickly solidify and form an expansion joint structure with water-stopping function.

[0206] The high-toughness cement-based grouting material is prepared as follows:

[0207] 1) Raw materials comprising the following weight proportions;

[0208] (a) 1000 parts of general-purpose Portland cement PO42.5;

[0209] 500 portions of water;

[0210] (b) Admixtures

[0211] 75 parts of polycarboxylate superplasticizer;

[0212] Drag-reducing agent: 70 parts of zwitterionic polyacrylamide;

[0213] 180 parts of hydroxypropyl methylcellulose;

[0214] 175 parts of hydroxyethyl cellulose;

[0215] 50 parts of triethanolamine;

[0216] 40 portions of NNO;

[0217] 100 parts latex powder;

[0218] 230 parts of quick-setting agent (powder);

[0219] (c) Admixtures

[0220] 250 portions of fly ash of grade II or above;

[0221] Silica fume, with a SiO2 content of not less than 90% and a specific surface area of ​​16,000 square meters per kilogram, 75 parts;

[0222] 75 parts of 10-30 mm polypropylene fiber;

[0223] (d) Aggregates

[0224] 1750 portions of gravel with a particle size of less than 5 mm;

[0225] 1500 parts of medium-coarse sand;

[0226] 2) Mixing materials

[0227] According to actual requirements, select the material proportions from (a) to (d) for mixing, and control the expansion during grouting to 500mm;

[0228] The grouting process into the forward hole is as follows:

[0229] 1) Grouting is performed using a screw pump through a double-slurry pressureless grouting pipe 3. The grouting pipe 303 is connected to a polyurethane grouting pump 80cm from the grout outlet. Figure 3 Simultaneously, polyurethane grout is injected to mix the polyurethane with the cement-based grout. The amount of polyurethane added can be adjusted using a diluent.

[0230] Polyurethane grout preparation:

[0231] 550 parts of single-component polyurethane;

[0232] Diluent: 550 parts xylene or acetone;

[0233] The dual-screw pressureless grouting pipe 3 includes a screw pump connection port 2 301, an opening adjustment valve 302, a grouting pipe body 303, a polyurethane grouting pump connection port 2 304, an opening adjustment valve 4 305, and a grout outlet 306. The grouting pipe body 303 has a screw pump connection port 1 301, a polyurethane grouting pump connection port 2 304, and a grout outlet 306. An opening adjustment valve 302 is located at the screw pump connection port 1 301, and an opening adjustment valve 4 305 is located at the polyurethane grouting pump connection port 2 304.

[0234] (2) Grouting is carried out by inserting a buried pipe: first insert the grouting pipe to the bottom, and then grout.

[0235] (3) Start pulling the pipe upwards when the grout has buried the grouting port for about 20cm;

[0236] (4) Grouting continues until the top is sealed, and the expansion joint waterproofing repair is completed.

[0237] Example 3

[0238] Includes the following steps:

[0239] (1) Drill two holes along the expansion joint where the waterproofing is damaged, extending 1 meter beyond the foundation surface. Figure 4 , 5 ;

[0240] Using a double-hole method, if the construction layout is convenient, drill one hole 20cm downstream and 20cm upstream of the damaged expansion joint waterstop; if the layout is inconvenient, drill two holes downstream of the expansion joint at a convenient location, with a distance of L=50cm between the two holes.

[0241] (2) Prepare on-site slurry A and B, which are driftable flocculants that can quickly solidify and seal flowing water in expansion joints, and mix them on-site at a mass ratio of 1:0.95, controlling the slurry diffusion to be greater than 400mm; including:

[0242] 1) Calculate the time from the feeding trough 1 to the shrinkage outlet 206, and add 45 seconds to this time as the setting time of the prepared slurry;

[0243] 2) Slurries A and B, which can rapidly coagulate drifting flocs, are prepared simultaneously on-site; wherein:

[0244] i) Prepare a slurry A with the following weight parts of a driftable flocculant that can coagulate rapidly;

[0245] General-purpose Portland cement PO42.5, 1000 parts;

[0246] 700 portions of fly ash of grade II or above;

[0247] Silica fume, with a SiO2 content of not less than 90% and a specific surface area of ​​20,000 square meters / kg, 150 parts;

[0248] Cryopreservation beads: 550 parts of hollow glass microspheres made from fly ash;

[0249] 150 parts of short fibers, 10-30 mm in diameter;

[0250] 1460 portions of water;

[0251] 50 parts of polycarboxylate superplasticizer;

[0252] Drag-reducing agent: 140 parts of zwitterionic polyacrylamide;

[0253] 150 parts of hydroxyethyl cellulose;

[0254] 200 parts of hydroxypropyl methylcellulose;

[0255] Add appropriate amounts of various materials to a non-aluminum preparation container and mix until the diffusion degree is not less than 400 mm.

[0256] ii) Prepare a slurry B with the following weight proportions of driftable flocculants that can rapidly coagulate;

[0257] Water glass, 10–45 Bé, modulus 1.5–3.0, 1000 parts

[0258] 1060 portions of purified water

[0259] The preparation process involves diluting the water glass with pure water in a non-aluminum preparation container. First, pour in the water glass, then slowly add water while stirring.

[0260] iii) When the diffusion of both driftable flocs A and B is greater than 400 mm, the specially made feeding trough 1 with a feeding amount control device is used. Figure 1 Installed on the feed port of the screw pump, the material is fed into the self-made feed trough 1 according to the ratio. The feeding amount is controlled by the controller of the feed trough. The two slurries are mixed in the screw pump and can be used directly for grouting.

[0261] When preparing slurry A, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0262] a) If there are requirements for early strength and later strength, 150 parts of triethanolamine can be used for adjustment;

[0263] b) If there are requirements for the toughness of the material after solidification, it can be adjusted with 12 parts NNO, 200 parts acrylic emulsion or 150 parts water-based epoxy resin.

[0264] When preparing slurry B, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included:

[0265] a) To shorten the setting and curing time of the slurry, add 120 parts of sodium hydroxide;

[0266] b) If it is necessary to delay the setting time of the slurry, use any of the following methods:

[0267] ① Add 5-100 parts of liquid inorganic silica gel and 5-50 parts of disodium hydrogen phosphate;

[0268] ② Add 10-300 parts of silica fume and 5-50 parts of disodium hydrogen phosphate;

[0269] If the solidification is too fast, liquid inorganic silica gel and disodium hydrogen phosphate can be added to prolong the solidification time. If the solidification is too slow, sodium hydroxide can be prepared as a solution and then added.

[0270] The feeding trough 1 includes a trough body 101, a central partition 102, a feeding port 103, a feeding port 2 104, a discharge gate 105 with an opening adjustment valve, and a discharge gate 2 106 with an opening adjustment valve, as well as a controller. The central partition 102 divides the trough body 101 into two parts. The upper part of the trough body 101 has a feeding port 103 and a feeding port 2 104. The discharge gates 105 and 2 106 with opening adjustment valves are installed at the bottom discharge ports, respectively. The opening adjustment of each discharge gate is completed by the controller.

[0271] (3) Grouting the downstream borehole using a screw pump and a booster double-slurry grouting head; including:

[0272] 1) Grouting is performed using a screw pump. At the outlet of the grouting pipe, a booster double-slurry grouting head 2 is connected to the polyurethane grouting pump (see...). Figure 2 Insert the grouting pipe directly to the bottom of the hole and simultaneously inject grout A and B, which can drift and flocculate rapidly, and polyurethane grout.

[0273] Preparation of polyurethane slurry:

[0274] 1000 parts of single-component polyurethane;

[0275] Diluent: 1100 parts xylene or acetone;

[0276] Polyurethane in pressurized double-slurry injection port ( Figure 2The injection volume of polyurethane is adjusted using the switch opening of the polyurethane pump;

[0277] 2) Observe the water flow at the leak point. When the downstream outlet water flow rate decreases significantly, it indicates that the gap or orifice has been sealed. At this time, grout can be injected directly to the top of the hole to complete the temporary water-stopping operation of the hole.

[0278] The pressurized double-slurry grouting head 2 includes a screw pump connection port 201, an opening adjustment valve 202, a polyurethane grouting pump connection port 203, an opening adjustment valve 204, a grouting head body 205, and a shrinkage grout outlet 206. The grouting head body 205 has a screw pump connection port 201, a polyurethane grouting pump connection port 203, and a shrinkage grout outlet 206. An opening adjustment valve 202 is located at the screw pump connection port 201, and an opening adjustment valve 204 is located at the polyurethane grouting pump connection port 203.

[0279] (4) Use high-toughness cement-based grouting material to grout the front hole until the front hole is full. Since the water level does not change significantly in a short time, the grout in the hole will quickly solidify and form an expansion joint structure with water-stopping function.

[0280] The high-toughness cement-based grouting material is prepared as follows:

[0281] 1) Raw materials comprising the following weight proportions;

[0282] (a) 1000 parts of general-purpose Portland cement PO42.5;

[0283] 800 portions of water;

[0284] (b) Admixtures

[0285] 150 parts of polycarboxylate superplasticizer;

[0286] Drag-reducing agent: 140 parts of zwitterionic polyacrylamide;

[0287] 350 parts of hydroxypropyl methylcellulose;

[0288] 350 parts of hydroxyethyl cellulose;

[0289] 100 parts of triethanolamine;

[0290] 80 portions of NNO;

[0291] 200 parts of latex powder;

[0292] 250 parts of quick-setting agent (powder);

[0293] (c) Admixtures

[0294] 700 portions of fly ash of grade II or above;

[0295] Silica fume, with SiO2 content not less than 90%, specific surface area of ​​20,000 square meters / kg, 150 parts;

[0296] 150 parts of 10-30 mm polypropylene fiber;

[0297] (d) Aggregates

[0298] 3500 parts of gravel with a particle size of less than 5 mm;

[0299] 3000 parts of medium-coarse sand;

[0300] 2) Mixing materials

[0301] According to actual requirements, select the material proportions from (a) to (d) for mixing, and control the expansion during grouting to 600mm;

[0302] The grouting process into the forward hole is as follows:

[0303] 1) Grouting is performed using a screw pump through a double-slurry pressureless grouting pipe 3. The grouting pipe 303 is connected to a polyurethane grouting pump 80cm from the grout outlet. Figure 3 Simultaneously, polyurethane grout is injected to mix the polyurethane with the cement-based grout. The amount of polyurethane added can be adjusted using a diluent.

[0304] Polyurethane grout preparation:

[0305] 1100 parts of single-component polyurethane;

[0306] Diluent: 1100 parts xylene or acetone;

[0307] The dual-screw pressureless grouting pipe 3 includes a screw pump connection port 2 301, an opening adjustment valve 302, a grouting pipe body 303, a polyurethane grouting pump connection port 2 304, an opening adjustment valve 4 305, and a grout outlet 306. The grouting pipe body 303 has a screw pump connection port 1 301, a polyurethane grouting pump connection port 2 304, and a grout outlet 306. An opening adjustment valve 302 is located at the screw pump connection port 1 301, and an opening adjustment valve 4 305 is located at the polyurethane grouting pump connection port 2 304.

[0308] (2) Grouting is carried out by inserting a buried pipe: first insert the grouting pipe to the bottom, and then grout.

[0309] (3) Start pulling the pipe upwards when the grout has buried the grouting port about 20cm deep; at this time, pulling the pipe is not difficult.

[0310] (4) Grouting continues until the top is sealed, and the expansion joint waterproofing repair is completed.

[0311] The invention will be further illustrated below with specific experimental examples.

[0312] Experimental Example: Application of Rapid Repair of Expansion Joint Waterproofing Function

[0313] After the construction of a hydroelectric power station, a leak occurred in an expansion joint of the water-retaining structure. The expansion joint was 2.5 cm wide, and the joint sealant was made of polystyrene board (e.g., ...). Figure 4 (As shown). Due to severe leakage, the four 6-inch pumps inside the powerhouse have been pumping water with little effect, and the water level is approaching the submersion line of the generator units. This has rendered the underwater powerhouse unable to operate normally, necessitating the removal of the generator units from the powerhouse. This not only seriously affects the power generation efficiency of the hydroelectric power station but also poses a threat to the safe operation of the project, requiring immediate repair work.

[0314] Using this invention to repair the expansion joint with water stop can restore its water-stopping function.

[0315] (1). Drill two holes at the expansion joint.

[0316] Because it was inconvenient to install a drilling rig at the original expansion joint location of the water-retaining structure, two holes were drilled downstream of the original expansion joint water-stop structure, with a hole diameter R=70mm (e.g., Figure 4 , 5 As shown in the diagram, the distance between the two holes is L=50 cm, and the hole depth exceeds the foundation depth by 1 meter, with an actual drilling depth of 19.90 meters. Actual measurements show that the upstream water depth is H=15.5 meters, the downstream water depth is h=8.5 meters, and the water level difference between the upstream and downstream is approximately 7 meters. To ensure the drill bit drills downwards along the expansion joint direction, a drill bit guide was used during construction.

[0317] (2). Quickly seal the flowing water in the expansion joint.

[0318] 1) The calculated time from the feeding trough to the grout outlet of the injection pipe is 55 seconds. Based on this time, the grout is prepared according to a setting time of 75 seconds.

[0319] 2) On-site preparation of slurries A and B, which are designed to rapidly seal flowing water in expansion joints and allow for the rapid coagulation of drifting flocs, wherein:

[0320] i) Preparation of rapid setting slurry A

[0321] 1000 parts of cement PO42.5;

[0322] Cryopreservation beads: 400 parts of hollow glass microspheres made from fly ash;

[0323] 80 parts of short fibers, 10-30 mm in diameter;

[0324] 460 portions of water;

[0325] 5 parts of polycarboxylate superplasticizer;

[0326] Drag reducer: 6 parts of zwitterionic polyacrylamide;

[0327] 5 parts hydroxypropyl methylcellulose;

[0328] 4 parts hydroxyethyl cellulose;

[0329] One part of triethanolamine;

[0330] Add appropriate amounts of various materials to a non-aluminum preparation container and mix until the diffusion degree is not less than 400 mm.

[0331] ii) Prepare rapid-setting slurry B;

[0332] Water glass (45 Bé, modulus 2.0) 1000 parts;

[0333] Sodium hydroxide (to reduce the modulus of water glass, for later use) 120 parts;

[0334] 100 parts of liquid inorganic silica gel (to improve the modulus of water glass, for later use);

[0335] 70 parts of disodium hydrogen phosphate;

[0336] 260 portions of purified water;

[0337] The preparation process involves first diluting the water glass with purified water in a non-aluminum container. The water glass is poured in first, followed by slowly adding water while stirring. Sodium hydroxide is added to lower the modulus of the water glass, and inorganic silica gel is added to increase the modulus. After mixing, a diffusion degree of 720 mm is achieved.

[0338] If the coagulation is too fast, an appropriate amount of disodium hydrogen phosphate can be added to prolong the coagulation time, or an appropriate amount of liquid inorganic silica gel can be added; if the coagulation is too slow, an appropriate amount of sodium hydroxide solution can be added.

[0339] This invention employs a screw pump. When the diffusion degree of both slurries A and B is greater than 400 mm, the slurry is fed through a specially manufactured feeding trough equipped with a feeding controller. Figure 1 The mixing effect of the two slurries in the screw pump can directly meet the grouting requirements.

[0340] iii) Mix slurries A and B in a ratio of 1:0.8, prepare a quick-setting slurry through on-site testing, and measure its setting time to the outlet of the delivery pipe to obtain a slurry with good fluidity.

[0341] (3) Grouting is performed in the downstream direction through a screw pump and a booster double-slurry grouting head;

[0342] 1) Grouting is performed using a screw pump. In underwater areas, a booster-type double-slurry grouting head is used, and a polyurethane grouting pump is connected to the booster-type grouting head at the outlet of the grouting pipe. Figure 2 Simultaneous injection of polyurethane grout; specific preparation:

[0343] 800 parts of single-component polyurethane;

[0344] 400 parts xylene or acetone (as a backup diluent);

[0345] The amount of polyurethane pumped in is controlled by adding a diluent, wherein the amount of acetone added is 180 parts.

[0346] The pressure-released slurry at the outlet allows the two slurries to directly form a flocculated state, which helps to quickly seal the flowing water between the expansion joint and the caulking plate. If the polyurethane pump opening is too narrow when adjusting the amount of polyurethane added, causing difficulty in discharging, xylene or acetone can be added as a diluent for adjustment.

[0347] 2) Observe the water level changes at the expansion joint while grouting. If the water level in the upstream hole rises significantly, it indicates that the gap has been basically sealed successfully, and the temporary sealing is complete. Because water glass has a certain water-corroding property, long-term immersion in water may lead to insufficient durability.

[0348] (4) In order to improve the durability of water-stopping and extend the effective water-stopping time, the new type of expansion joint water-stopping grout is used to fill and seal the hole.

[0349] 1) Rapidly construct high-toughness cement-based waterproofing materials for long-term sealing of expansion joints;

[0350] Since the downstream hole has already sealed off the leakage caused by the expansion joint failure, the water in the upstream hole will not continue to flow. At this point, a new type of semi-rigid water-stop structure can be constructed using underwater high-toughness cement-based materials to quickly seal the expansion joint and form a new type of water-stop that can withstand certain limited deformation.

[0351] Preparation of grout for constructing high-toughness cement-based waterproofing material for expansion joints;

[0352] (a) Cement

[0353] General-purpose Portland cement PO42.5, 1000 parts;

[0354] 470 portions of water;

[0355] (b) Admixtures

[0356] 5 parts of polycarboxylate superplasticizer;

[0357] 4 parts of zwitterionic polyacrylamide (drag reducer);

[0358] 6 parts of hydroxypropyl methylcellulose;

[0359] 5 parts hydroxyethyl cellulose;

[0360] Two parts of triethanolamine;

[0361] 3 portions of NNO;

[0362] 58 parts latex powder;

[0363] 100 parts of quick-setting agent (powder);

[0364] One part of air-entraining agent;

[0365] (c) Admixtures

[0366] 200 portions of Class II or higher fly ash;

[0367] Silica fume, with a SiO2 content of not less than 90% and a specific surface area of ​​13,000 m² / kg to 20,000 m² / kg (30 parts);

[0368] 10 parts of 10-30 mm polypropylene fiber;

[0369] (d) Aggregates

[0370] 100 portions of 5 mm diameter gravel;

[0371] 300 parts of medium-coarse sand;

[0372] 2) Select materials from (a) to (d) according to actual requirements for mixing. The expansion during grouting can be controlled between 400 and 550 mm.

[0373] The grouting process in the forward hole is as follows:

[0374] 1) Grouting is performed using a screw pump. The pump's own feed trough is used to inject high-toughness cement-based grout into both underwater and above-water areas using pressureless grouting pipes. A polyurethane grouting pump is connected to the grouting pipe 80 cm from the outlet (see...). Figure 3 Simultaneously inject polyurethane grout to ensure thorough mixing of the polyurethane with the cement-based grout; the polyurethane grout is prepared as follows:

[0375] 800 parts of single-component polyurethane;

[0376] 400 parts xylene or acetone (for backup, diluent);

[0377] The amount of polyurethane added was controlled by a diluent; in this case, 180 parts of acetone were used.

[0378] 2) The grouting operation adopts the pipe insertion and embedment method;

[0379] 3) Pull out the pipe when the grout has buried about 20cm of the injection port;

[0380] 4) The work is completed when the concrete is poured to the top.

[0381] The material begins to set 25 minutes after being discharged and begins to gain strength after 30 minutes. That is, the expansion joint waterproofing structure has officially begun to bear the load 30 minutes after the capping.

[0382] Excluding drilling time, the temporary hole sealing for this project took less than 2 hours, and the total time to complete the expansion joint waterproofing work was less than 4 hours.

[0383] Because the engineering problems were dealt with in a timely manner, the project was able to operate normally, not only safely through the winter but also successfully through the spring and summer floods, ensuring the safety of the project without any abnormalities.

Claims

1. A method of repairing an underwater expansion joint seal with a cementitious material, characterized by, Includes the following steps: (1) Drill 1-2 holes along the expansion joint where the water stop is damaged, with a depth 1 meter beyond the depth of the structural foundation surface; (2) Prepare slurry A and B on-site, which are driftable flocculants that can quickly solidify and seal the flowing water in the expansion joint. Mix them on-site at a mass ratio of 1:(0.5 to 0.95) to prepare the slurry, and control the slurry diffusion to be greater than 400 mm. (3) Grouting is performed in the downstream direction through a screw pump and a booster double-slurry grouting head; (4) Use high-toughness cement-based grouting material to grout the front hole until it is filled to form an expansion joint structure with water-stopping function.

2. The method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 1, characterized in that: In step (1), double holes are used. If the construction layout is convenient, one hole is drilled 8-20cm downstream and upstream of the damaged expansion joint waterstop. If the layout is inconvenient, two holes are drilled in the downstream direction of the expansion joint at a convenient location, with a distance of L=20-50cm between the two holes.

3. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 1, characterized in that: Step (2) includes: 1) Calculate the time from the feeding trough to the shrinkage outlet, and add 20 to 45 seconds to this time as the setting time of the prepared slurry; 2) Slurries A and B, which can rapidly coagulate drifting flocs, are prepared simultaneously on-site; wherein: i) Prepare a slurry A with the following weight parts of a driftable flocculant that can coagulate rapidly; General-purpose Portland cement PO42.5, 1000 parts; 200-700 parts of Class II or higher fly ash; Silica fume, wherein the SiO2 content is not less than 90%, and the specific surface area is 13,000 m² / kg to 20,000 m² / kg, 2 to 150 parts; Cenospheres: 5-550 parts of hollow glass microspheres made from fly ash; 10-30 mm short fibers, 1-150 parts; Water 200-1460 parts; 3-50 parts of polycarboxylate superplasticizer; Drag-reducing agent: 1-140 parts of zwitterionic polyacrylamide; 1-150 parts of hydroxyethyl cellulose; 1-200 parts of hydroxypropyl methylcellulose; Add appropriate amounts of various materials to a non-aluminum preparation container and mix until the diffusion degree is not less than 400 mm. ii) Prepare a slurry B with the following weight proportions of driftable flocculants that can rapidly coagulate; Water glass, 10–45 Bé, modulus 1.5–3.0, 1000 parts 200-1060 parts purified water The preparation process involves diluting the water glass with pure water in a non-aluminum preparation container. First, pour in the water glass, then slowly add water while stirring. iii) When the diffusion of slurries A and B, which can rapidly coagulate driftable flocs, is greater than 400 mm, a specially made feeding trough with a feeding amount control device is installed on the feeding port of the screw pump. The two slurries are fed in proportion in the self-made feeding trough, and the feeding amount is controlled by the controller of the feeding trough. The two slurries are mixed in the screw pump.

4. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 3, characterized in that: When preparing slurry A, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included: a) If there are requirements for early strength and later strength, triethanolamine 1-150 parts can be used for adjustment; b) If there are requirements for the toughness of the material after solidification, it can be adjusted with 1-12 parts of NNO, 5-200 parts of acrylic emulsion or 5-150 parts of water-based epoxy resin. When preparing slurry B, which allows for rapid coagulation of drifting flocs, auxiliary ingredients are also included: a) To shorten the setting and curing time of the slurry, add 5-120 parts of sodium hydroxide; b) If it is necessary to delay the setting time of the slurry, use any of the following methods: ① Add 5-100 parts of liquid inorganic silica gel and 5-50 parts of disodium hydrogen phosphate; ② Add 10-300 parts of silica fume and 5-50 parts of disodium hydrogen phosphate.

5. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 3, characterized in that: The feeding trough includes a trough body, a central partition, a feeding port one, a feeding port two, a discharge gate one with an opening adjustment valve, a discharge gate two with an opening adjustment valve, and a controller. The central partition divides the trough body into two parts. The upper part of the trough body has a feeding port one and a feeding port two. The discharge gate one with an opening adjustment valve and the discharge gate two with an opening adjustment valve are respectively installed at the discharge ports at the bottom. The opening adjustment of each discharge gate is completed by the controller.

6. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 1, characterized in that: Step (3) includes: 1) Use a screw pump for grouting. Connect the grouting pipe outlet to the polyurethane grouting pump through a pressurized double grouting head. Insert the grouting pipe directly to the bottom of the hole and simultaneously inject grout A and B, which can drift flocs and quickly solidify, and polyurethane grout. Preparation of polyurethane slurry: 1000 parts of single-component polyurethane; Diluent: 50-1100 parts xylene or acetone; The injection volume of polyurethane is adjusted by the switch opening of the polyurethane pump at the pressurized double-slurry grouting port. 2) Observe the water flow at the leak point. When the downstream outlet water flow rate decreases significantly, it indicates that the gap or orifice has been sealed. At this time, grout can be injected directly to the top of the hole to complete the temporary water-stopping operation of the hole.

7. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 6, characterized in that: The pressurized dual-slurry grouting head includes a screw pump connection port one, an opening adjustment valve one, a polyurethane grouting pump connection port one, an opening adjustment valve two, a grouting head body, and a shrinkage grout outlet. The grouting head body has a screw pump connection port one, a polyurethane grouting pump connection port one, and a shrinkage grout outlet. There is an opening adjustment valve one at the screw pump connection port and an opening adjustment valve two at the polyurethane grouting pump connection port one.

8. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 1, characterized in that: The high-toughness cement-based grouting material in step (4) is prepared as follows: 1) Raw materials comprising the following weight proportions; (a) 1000 parts of general-purpose Portland cement PO42.5; 200-800 parts water; (b) Admixtures 3-150 parts of polycarboxylate superplasticizer; Drag-reducing agent: 2-140 parts of zwitterionic polyacrylamide; 3-350 parts of hydroxypropyl methylcellulose; 1-350 parts of hydroxyethyl cellulose; Triethanolamine 1-100 parts; Sodium methylene dinaphthalene sulfonate (NNO) 1-80 parts; 1-200 parts of latex powder; 1-250 parts of quick-setting agent; (c) Admixtures 500-700 parts of fly ash of grade II or above; Silica fume, with a SiO2 content of not less than 90% and a specific surface area of ​​13,000 m² / kg to 20,000 m² / kg, and 3 to 150 parts; 2-150 parts of 10-30 mm polypropylene fiber; (d) Aggregates 3-3500 parts of gravel with a particle size of less than 5 mm; Medium to coarse sand, 3000-3000 parts; 2) Mixing materials According to actual requirements, select the material proportions in (a) to (d) for mixing, and control the expansion during grouting to 400-600mm.

9. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 8, characterized in that: The grouting process in step (4) is as follows: 1) Use a screw pump to inject grout through a double-slurry pressureless grouting pipe. Connect a polyurethane grouting pump 80cm away from the grout outlet of the grouting pipe and inject polyurethane grout at the same time to mix the polyurethane with the cement-based grout. Polyurethane grout preparation: 2 to 1100 parts of single-component polyurethane; Diluent: 1-1100 parts xylene or acetone; (2) Grouting is carried out by inserting a buried pipe: first insert the grouting pipe to the bottom, and then grout. (3) Start pulling the pipe upwards when the grout has buried the grouting port for about 20cm; (4) Grouting continues until the top is sealed, and the expansion joint waterproofing repair is completed.

10. A method for repairing underwater expansion joint waterproofing using cement-based materials according to claim 8, characterized in that: The dual-slurry pressureless grouting pipe includes a screw pump connection port 2, an opening adjustment valve 3, a grouting pipe body, a polyurethane grouting pump connection port 2, an opening adjustment valve 4, and a grout outlet. The grouting pipe body has a screw pump connection port 1, a polyurethane grouting pump connection port 2, and a grout outlet. An opening adjustment valve 3 is located at the screw pump connection port, and an opening adjustment valve 4 is located at the polyurethane grouting pump connection port 2.

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