Method for closing settlement post-cast strip of underground garage in advance

Abstract

The invention relates to a method for closing a settlement post-cast strip of an underground garage in advance. According to the invention, the high-performance recycled aggregate is used as a main framework of the concrete, high strength and stability are provided, and the use amount of water is reduced by the super-efficient water reducing agent, so that the porosity of the concrete is reduced, and the compactness and impermeability of the concrete are improved. The fine mineral admixture and the polymer emulsion can be used for filling tiny pores in the concrete, so that the compactness is further improved, and meanwhile, the anti-cracking performance of the concrete is improved. The silicate early strength agent promotes the early strength development of the concrete, so that the post-cast strip can bear the load as soon as possible, and the construction period is shortened. The nanoscale anticorrosive agent and the nano-silver antibacterial agent provide long-term anticorrosive and antibacterial protection for the concrete, and the service life of the post-cast strip is prolonged. The glass fibers or the carbon fibers are doped, so that the tensile strength and the toughness of the concrete are enhanced, and generation and development of cracks are effectively prevented.

Description

Technical Field

[0001] The invention relates to an underground garage construction method, in particular to a method for early sealing of a post-settlement cast-in-place strip of an underground garage. Background Art

[0002] With the acceleration of urbanization, the demand for underground garage construction is growing. However, during the construction of underground garages, settlement often occurs due to geological conditions, construction quality and other reasons. Settlement can cause deformation, cracks and even damage to the structure of underground garages, seriously affecting their service life and safety. In order to prevent the occurrence of settlement, the traditional treatment method is to seal the post-casting strip after the settlement is stable.

[0003] However, traditional concrete materials are susceptible to corrosion and erosion in underground environments, resulting in a decrease in structural performance. Traditional steel reinforcement materials are also susceptible to corrosion, affecting the bearing capacity of the structure. In addition, the traditional post-casting strip sealing method is prone to quality problems such as leakage and hollowing during construction, affecting the durability and safety of the structure. Summary of the invention

[0004] The purpose of the present invention is to provide a method for early sealing of the settlement post-cast strip of an underground garage, so as to solve the problem that the traditional post-cast strip sealing method is prone to quality problems such as leakage and hollowing, which affects the durability and safety of the structure.

[0005] The present invention is implemented in this way: a method for early sealing of a settlement cast-in-place strip of an underground garage, the method comprising the following steps.

[0006] S1: Conduct investigation and analysis: Conduct a detailed investigation on the settlement of the underground garage to understand the cause, scope and degree of settlement; analyze the current status of the settlement post-cast strip, including the width, depth and material of the post-cast strip.

[0007] S2: Develop a plan: Based on the survey results, develop a plan for early closure of the post-settlement pouring zone; determine the construction process, materials and equipment requirements.

[0008] S3: Carry out preparatory work: clean up the debris in the post-cast strip to ensure that the construction surface is clean and tidy; roughen the concrete on both sides of the post-cast strip to increase the bonding strength between the new and old concrete.

[0009] S4: Carry out steel bar processing: according to the design plan, cut, weld and tie the steel bars in the post-cast zone; ensure that the spacing and diameter of the steel bars meet the design requirements.

[0010] S5: Set up formwork: Set up formwork on both sides of the post-casting strip. The formwork should have a certain strength and rigidity; ensure that the formwork is tightly spliced ​​to prevent leakage during concrete pouring.

[0011] S6: An advanced water-stopping concrete belt and a waterproof layer are set at the lower part of the post-cast zone to achieve precipitation and drainage around the foundation pit.

[0012] S7: Prepare concrete, weigh: high-performance recycled aggregate: 1100-1200 parts by weight; high-efficiency coagulant: 80-100 parts by weight; adjusted water with a pH value of 8-9: 150-200 parts by weight; super-efficient water reducer: 10-50 parts by weight; fine mineral admixture: 50-200 parts by weight; polymer emulsion: silicone-acrylic emulsion: 18-20 parts by weight; silicate early strength agent: 25-35 parts by weight; nano-scale anticorrosive agent: 100-120 parts by weight; glass fiber or carbon fiber: 250-290 parts by weight; nano-silver antibacterial agent: 120-140 parts by weight; supported photocatalytic nanomaterial: 20-40 parts by weight; intelligent shape memory alloy fiber: 20-40 parts by weight; magnetic nanoparticles: 20-50 parts by weight; The weighed raw materials are then used to prepare concrete.

[0013] S8: After the concrete pouring is completed, cover and water it in time for maintenance; the maintenance time should be no less than 7 days.

[0014] S9: After the concrete strength reaches the design requirements, remove the formwork; during the formwork removal process, pay attention to protecting the concrete surface to avoid damage.

[0015] S10: Carry out quality inspection on the sealed post-cast joints, including concrete strength and appearance; if there are any quality problems, take timely measures to rectify them.

[0016] S11: Regularly monitor the closed post-cast strip and observe its operating conditions; promptly handle any problems found to ensure safe use of the underground garage.

[0017] In the step S1, a high-precision level is used to observe the settlement, and the cumulative settlement and settlement rate of each observation point are recorded to ensure that the observation error is less than 1 mm; the physical and mechanical properties of the soil layer are analyzed through the geological survey report, including the compression modulus, Poisson's ratio, and cohesion of the soil; an ultrasonic detector is used to detect the compactness and internal defects of the concrete on both sides of the post-cast strip; the size of the post-cast strip is recorded in detail, the width is 800-1200 mm, the depth should reach at least 300 mm below the foundation bottom plate, and the material includes the strength grade of the concrete and the specification of the steel bar; In the step S2, the best time to close the post-casting strip is determined, which is carried out when the settlement rate is less than 0.01 mm / d; the construction method should specify the segment length, each segment should not exceed 20m, and the skip bin method should be used for construction; the concrete mix design should include a water-cement ratio not exceeding 0.45, a sand ratio of 40%-45%, and a maximum aggregate particle size not exceeding 25mm; the equipment requirements should list in detail the models and quantities of concrete mixers, pump trucks, and vibrators.

[0018] In step S3, when cleaning the debris in the post-casting strip, a high-pressure water gun should be used to rinse it to ensure that there is no oil stain or loose soil; a professional chiseling machine should be used for the roughening treatment, and the chiseling depth should be controlled at 8-12mm, and the chiseling area should not be less than 75% of the concrete surface; at the same time, the concrete on both sides of the post-casting strip should be polished to remove the loose layer and floating slurry; In step S4, the cutting length of the steel bars should be adjusted according to the specific conditions of the post-casting strip to ensure that the lap length is not less than 35 times the steel bar diameter required by the specification; carbon dioxide gas shielded welding should be used during welding, the weld width should be not less than 8 mm, and the weld height should be not less than 4 mm; when binding, the transverse and longitudinal spacing of the steel bars should be kept uniform, 150 mm and 200 mm respectively.

[0019] In step S5, a phenolic coated board with a thickness of not less than 15 mm or a steel plate with a thickness of not less than 6 mm is selected as the template; the template joints should be sealed with sealing strips or foam agents to ensure that the joint seams are less than 1.5 mm; the template support system adopts an adjustable steel pipe bracket, with the vertical pole spacing not exceeding 1 m and the horizontal pole spacing not exceeding 0.6 m to ensure the overall stability of the template.

[0020] In step S6, the drainage pipe should be made of PVC or HDPE pipe with a diameter of at least 110 mm, and the slope of the pipe should be maintained at more than 1% when laying; the pipe interface should be hot-melt welded, and the welding joint should be smooth and uniform, without cold welds or leaking welds; the area around the pipe should be filled with fine sand or concrete to prevent the pipe from shifting during the pouring process.

[0021] In the step S7, the preparation method of the supported photocatalytic nanomaterial includes: firstly dissolving tetrabutyl titanate Ti(OC4H9)4 as a precursor in anhydrous ethanol, and then slowly dropping it into a solution containing water and acid under stirring conditions to form a transparent TiO2 sol; by controlling the conditions of hydrolysis and condensation reactions, regulating the size and morphology of TiO2 nanoparticles; then aging, drying, and heat treating the sol to obtain TiO2 nanoparticles with high specific surface area and photocatalytic activity; The preparation method of intelligent shape memory alloy fiber includes: firstly melting nickel-titanium alloy, and then extruding the molten alloy through a spinneret under nitrogen protection to form filaments; the filaments are rapidly cooled and solidified in a cooling device to form continuous fibers; in this process, the diameter and shape memory performance of the fiber are controlled by adjusting the aperture of the spinneret, the temperature of the molten alloy, the extrusion speed and the cooling rate parameters; the prepared shape memory alloy fiber is subjected to heat treatment and shape memory training to give it a stable shape memory effect; finally, the fibers are cut into appropriate lengths for use in concrete reinforcement; The preparation method of magnetic nanoparticles includes: firstly dissolving iron salt FeCl3 and ferrous salt FeSO4 in deionized water according to a certain ratio, then heating the mixed solution under nitrogen protection, and quickly adding alkaline NaOH solution to adjust the pH value, so as to promote the coprecipitation reaction of iron ions and ferrous ions to form magnetic Fe3O4 nanoparticles; by controlling the reaction temperature, pH value, reaction time and stirring speed parameters, the size and magnetic properties of the nanoparticles are regulated; after the reaction is completed, the magnetic nanoparticles are separated and purified by centrifugation, washing and drying and other steps; The preparation method of concrete is as follows: first, accurately weigh high-performance recycled aggregate according to the ratio and put it into a concrete mixer; then, add high-efficiency coagulant and fine mineral admixture, and start the mixer for preliminary mixing; then, gradually add adjustment water and super-efficient water reducer, and continue to stir until the mixture is uniform to ensure that the concrete has good working performance; then, add polymer emulsion and silicate early strength agent to improve the early strength and durability of concrete; during the mixing process, gradually add nano-scale anti-corrosion agent, glass fiber or carbon fiber and nano-silver antibacterial agent to enhance the anti-corrosion, anti-cracking and antibacterial properties of concrete; the entire mixing process should continue until all ingredients are completely dispersed and evenly dispersed to form a concrete mixture with uniform texture and good fluidity; finally, the mixed concrete is transported to the construction site in time, and poured, vibrated and cured according to the construction requirements to ensure the strength and durability of the concrete structure.

[0022] In step S8, during the curing process, the concrete covering material should be wet sacks or wet straw mats, and the thickness of the covering layer should be not less than 20 mm; the frequency of watering should be adjusted according to local climatic conditions, and water should be sprinkled every 2-4 hours to keep the concrete surface moist; during the curing period, a cordon should be set to avoid human damage and vehicle crushing.

[0023] In step S9, the concrete strength should be tested by a rebound tester and reach more than 75% of the design strength; when removing the formwork, the formwork that has the greatest impact on the support of the concrete surface should be removed first, and then the other formworks should be gradually removed; during the formwork removal process, the formwork should be gently tapped with a wooden hammer to avoid damage to the concrete surface.

[0024] In step S10, the appearance inspection uses a magnifying glass to observe the concrete surface and record the width, length and distribution of the cracks; if there are quality problems, reinforcement measures should include carbon fiber cloth pasting and grouting reinforcement, and the repair material should be the same as the original concrete material.

[0025] In step S11, the monitoring cycle should be adjusted according to seasonal changes and groundwater level conditions, and monitoring should be intensified during the rainy season or when the groundwater level rises; the monitoring content includes the settlement, horizontal displacement, and crack development of the post-casting strip, and observations are made using precision levels and total stations; the monitoring data should be recorded in a timely manner and processed through data analysis software, and the emergency plan should be immediately activated when an abnormal situation is found.

[0026] In the present invention, high-performance recycled aggregate as the main skeleton of concrete provides high strength and stability, while the use of high-efficiency coagulant and adjustment water ensures that concrete has good workability and pumpability. Super-efficient water reducing agent reduces the amount of water used, thereby reducing the porosity of concrete and improving its compactness and impermeability. Fine mineral admixtures and polymer emulsions can fill the tiny pores inside the concrete, further increase the compactness, and simultaneously improve the crack resistance of concrete. Silicate early strength agents promote the early strength development of concrete, so that the post-casting strip can bear the load as soon as possible, shortening the construction period. Nano-grade anti-corrosion agents and nano-silver antibacterial agents provide long-term anti-corrosion and antibacterial protection for concrete, extending the service life of the post-casting strip. The incorporation of glass fiber or carbon fiber enhances the tensile strength and toughness of concrete, effectively preventing the generation and development of cracks. The comprehensive use of these materials not only improves the mechanical properties of concrete, but also enhances its durability and crack resistance, providing reliable technical guarantee for the early closure of the post-casting strip of the underground garage settlement. The preparation and application of this high-performance concrete helps ensure the stability and safety of the post-casting belt under complex geological conditions, reduces the cost of later maintenance, and improves the overall use function and economic benefits of the underground garage. At the same time, the environmental protection characteristics of these materials also meet the requirements of the modern construction industry for green construction and sustainable development.

[0027] In the preparation stage, the debris in the post-casting zone was cleaned and roughened to create good conditions for the pouring of concrete. The accuracy of the steel bar treatment ensured the effective combination of new and old concrete and improved the integrity of the structure. In the later monitoring stage, continuous monitoring provided a guarantee for the long-term safe use of the underground garage, and timely discovered and dealt with safety hazards such as settlement and displacement, ensuring the safety and reliability of the underground garage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the method for early sealing of the post-cast strip of the underground garage settlement according to the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Embodiment 1 A method for early sealing of a post-cast zone of an underground garage after settlement, the method comprising the following steps.

[0031] S1: Conduct investigation and analysis: Conduct a detailed investigation on the settlement of the underground garage to understand the cause, scope and extent of the settlement. Analyze the current status of the settlement post-casting belt, including the width, depth and material of the post-casting belt.

[0032] S2: Develop a plan: Based on the survey results, develop a plan for early closure of the post-settlement pouring zone. Determine the construction process, materials and equipment requirements.

[0033] S3: Prepare: clean up the debris in the post-casting strip to ensure the construction surface is clean and tidy. Roughen the concrete on both sides of the post-casting strip to increase the bonding strength between the new and old concrete.

[0034] S4: Process the steel bars: Cut, weld and tie the steel bars in the post-casting zone according to the design plan. Ensure that the spacing and diameter of the steel bars meet the design requirements.

[0035] S5: Set up the formwork: Set up the formwork on both sides of the post-casting strip. The formwork should have a certain strength and rigidity. Ensure that the formwork is tightly spliced ​​to prevent leakage during concrete pouring.

[0036] S6: An advanced water-stopping concrete belt and a waterproof layer are set at the lower part of the post-cast zone to achieve precipitation and drainage around the foundation pit.

[0037] S7: Prepare concrete by weighing: high-performance recycled aggregate: 1100 parts by weight; high-efficiency coagulant: 80 parts by weight; adjusted water with a pH value of 8-9: 150 parts by weight; super-efficient water reducing agent: 10 parts by weight; fine mineral admixture: 50 parts by weight; polymer emulsion (such as silicone-acrylic emulsion): 18 parts by weight; silicate early strength agent: 25 parts by weight; nano-grade anticorrosive agent: 100 parts by weight; glass fiber or carbon fiber: 250 parts by weight; nano-silver antibacterial agent: 120 parts by weight; supported photocatalytic nanomaterial: 20 parts by weight; intelligent shape memory alloy fiber: 20 parts by weight; magnetic nanoparticles: 20 parts by weight; The preparation method of the supported photocatalytic nanomaterial includes: firstly, dissolving tetrabutyl titanate (Ti(OC4H9)4) as a precursor in anhydrous ethanol, and then slowly adding it dropwise into a solution containing water and acid under stirring conditions to form a transparent TiO2 sol; by controlling the conditions of hydrolysis and condensation reactions, the size and morphology of the TiO2 nanoparticles are regulated; then, the sol is aged, dried, and heat-treated at a certain temperature to obtain TiO2 nanoparticles with a high specific surface area and good photocatalytic activity.

[0038] The preparation method of intelligent shape memory alloy fiber includes: firstly melting nickel-titanium alloy, and then extruding the molten alloy through a spinneret under nitrogen protection to form filaments; the filaments are rapidly cooled and solidified in a cooling device to form continuous fibers; in this process, the diameter and shape memory performance of the fiber are controlled by adjusting the aperture of the spinneret, the temperature of the molten alloy, the extrusion speed and the cooling rate parameters; the prepared shape memory alloy fiber needs to be heat treated and shape memory trained to give it a stable shape memory effect; finally, these fibers are cut into appropriate lengths for use in concrete reinforcement.

[0039] The preparation method of magnetic nanoparticles includes: firstly dissolving iron salt (such as FeCl3) and ferrous salt (such as FeSO4) in deionized water in a certain proportion, then heating the mixed solution under nitrogen protection, and quickly adding alkaline NaOH solution to adjust the pH value, so as to promote the co-precipitation reaction of iron ions and ferrous ions to form magnetic Fe3O4 nanoparticles; by controlling the reaction temperature, pH value, reaction time and stirring speed parameters, the size and magnetic properties of the nanoparticles are regulated; after the reaction is completed, the magnetic nanoparticles are separated and purified by centrifugation, washing and drying.

[0040] The weighed raw materials are then used to prepare concrete.

[0041] S8: After the concrete is poured, cover and water it in time for curing. The curing time should be no less than 7 days.

[0042] S9: After the concrete strength reaches the design requirements, remove the formwork. During the formwork removal process, pay attention to protecting the concrete surface to avoid damage.

[0043] S10: Check the quality of the closed post-casting strip, including concrete strength, appearance, etc. If there are any quality problems, take timely measures to rectify them.

[0044] S11: Regularly monitor the closed post-cast strip and observe its operating conditions. If any problems are found, deal with them promptly to ensure the safe use of the underground garage.

[0045] Among them, in step S1, a high-precision level is used to observe the settlement, and the cumulative settlement and settlement rate of each observation point are recorded to ensure that the observation error is less than 1mm. The physical and mechanical properties of the soil layer are analyzed through the geological survey report, including the compression modulus, Poisson's ratio, cohesion, etc. of the soil. An ultrasonic detector is used to detect the compactness and internal defects of the concrete on both sides of the post-cast strip. The size of the post-cast strip is recorded in detail. The width is usually 800-1200mm, and the depth should reach at least 300mm below the foundation slab. The material includes the strength grade of the concrete (such as C30, C35, etc.) and the specifications of the steel bars (such as HRB335, HRB400, etc.).

[0046] In step S2, the best time to close the post-casting strip is determined, which is carried out when the settlement rate is less than 0.01mm / d. The construction method should specify the segment length, each segment should not exceed 20m, and the skip bin method should be used for construction. The concrete mix design should include the water-cement ratio (not exceeding 0.45), sand ratio (40%-45%), maximum aggregate particle size (not exceeding 25mm), etc. The equipment requirements should list in detail the models and quantities of concrete mixers, pump trucks, vibrators, etc.

[0047] In step S3, when cleaning the debris in the post-casting zone, a high-pressure water gun should be used to flush it to ensure that there is no oil stain, loose soil, etc. A professional chiseling machine should be used for the roughening treatment, and the chiseling depth should be controlled at 8-12mm, and the chiseling area should not be less than 75% of the concrete surface. At the same time, the concrete on both sides of the post-casting zone should be polished to remove the loose layer and floating slurry.

[0048] In step S4, the cutting length of the steel bar should be adjusted according to the specific conditions of the post-casting strip to ensure that the lap length is not less than 35 times the steel bar diameter required by the specification. Carbon dioxide gas shielded welding should be used for welding, and the weld width should be not less than 8mm and the weld height should be not less than 4mm. When binding, the transverse and longitudinal spacing of the steel bars should be kept uniform, 150mm and 200mm respectively.

[0049] In step S5, a phenolic coated board with a thickness of not less than 15 mm or a steel plate with a thickness of not less than 6 mm is selected as the template. The template joints should be sealed with sealing strips or foam agents to ensure that the joint seams are less than 1.5 mm. The template support system should use an adjustable steel pipe bracket with a vertical pole spacing of no more than 1m and a horizontal pole spacing of no more than 0.6m to ensure the overall stability of the template.

[0050] In step S6, the drainage pipe should be made of PVC or HDPE pipe with a diameter of at least 110 mm, and the slope should be maintained at more than 1% when the pipe is laid. The pipe interface is welded by hot melt welding, and the welding joint should be smooth and uniform, without cold welding or leaking welding. Fine sand or concrete should be filled around the pipe to prevent the pipe from shifting during the pouring process.

[0051] In step S7, the preparation method of concrete is as follows: first, accurately weigh high-performance recycled aggregate according to the ratio and put it into a concrete mixer. Then, add high-efficiency coagulant and fine mineral admixture, and start the mixer for preliminary mixing. Subsequently, gradually add adjustment water and super-efficient water reducer, continue to stir until the mixture is uniform, and ensure that the concrete has good working performance. Then, add polymer emulsion (such as silicone-acrylic emulsion) and silicate early strength agent to improve the early strength and durability of concrete. During the stirring process, gradually add nano-scale anti-corrosion agent, glass fiber or carbon fiber and nano-silver antibacterial agent to enhance the corrosion resistance, crack resistance and antibacterial properties of concrete. The whole stirring process should continue until all ingredients are completely dispersed and uniform, forming a concrete mixture with uniform texture and good fluidity. Finally, the mixed concrete is transported to the construction site in time, and poured, vibrated and maintained according to the construction requirements to ensure the strength and durability of the concrete structure.

[0052] In step S8, during the curing process, the concrete covering material should be wet sacks or wet straw mats, and the thickness of the covering layer should be no less than 20 mm. The frequency of watering should be adjusted according to local climatic conditions, and water should be sprinkled every 2-4 hours to keep the concrete surface moist. During the curing period, a cordon should be set to avoid human damage and vehicle crushing.

[0053] In step S9, the concrete strength should be tested by a rebound hammer and reach more than 75% of the design strength. When removing the formwork, the formwork that has the greatest impact on the support of the concrete surface should be removed first, and then the other formworks should be removed step by step. During the demolding process, the formwork should be gently tapped with a wooden hammer to avoid damage to the concrete surface.

[0054] In step S10, the appearance inspection should use a magnifying glass to observe the concrete surface and record the crack width, length and distribution. If there are quality problems, reinforcement measures should include carbon fiber cloth pasting, grouting reinforcement, etc. The repair material should be the same as the original concrete material.

[0055] In step S11, the monitoring cycle should be adjusted according to seasonal changes and groundwater level conditions, and monitoring should be intensified during the rainy season or when the groundwater level rises. The monitoring content includes the settlement, horizontal displacement, crack development, etc. of the post-casting belt, and observations are made using precision leveling instruments, total stations and other equipment. The monitoring data should be recorded in a timely manner and processed through data analysis software, and the emergency plan should be activated immediately when abnormal conditions are found.

[0056] Embodiment 2 The other steps in this embodiment are the same as those in the first embodiment, except that step S7 uses a different ratio.

[0057] In step S7: concrete is prepared by weighing: high-performance recycled aggregate: 1200 parts by weight; high-efficiency coagulant: 100 parts by weight; adjusted water with a pH value of 8-9: 200 parts by weight; super-efficient water reducer: 50 parts by weight; fine mineral admixture: 200 parts by weight; polymer emulsion (such as silicone-acrylic emulsion): 20 parts by weight; silicate early strength agent: 35 parts by weight; nano-scale anticorrosive agent: 120 parts by weight; glass fiber or carbon fiber: 290 parts by weight; nano-silver antibacterial agent: 140 parts by weight; supported photocatalytic nanomaterial: 40 parts by weight; intelligent shape memory alloy fiber: 40 parts by weight; magnetic nanoparticles: 50 parts by weight.

[0058] The weighed raw materials are then used to prepare concrete.

[0059] The present invention uses high-performance recycled aggregate as the main skeleton of concrete, provides high strength and stability, and the use of high-efficiency coagulant and adjustment water ensures that the concrete has good workability and pumpability. Super-efficient water reducing agent reduces the amount of water used, thereby reducing the porosity of concrete and improving its compactness and impermeability. Fine mineral admixtures and polymer emulsions can fill the tiny pores inside the concrete, further increase the compactness, and simultaneously improve the crack resistance of the concrete. Silicate early strength agents promote the early strength development of concrete, so that the post-casting strip can bear the load as soon as possible, shortening the construction period. Nano-level anti-corrosion agents and nano-silver antibacterial agents provide long-term anti-corrosion and antibacterial protection for concrete, extending the service life of the post-casting strip. The incorporation of glass fiber or carbon fiber enhances the tensile strength and toughness of concrete, effectively preventing the generation and development of cracks. The comprehensive use of these materials not only improves the mechanical properties of concrete, but also enhances its durability and crack resistance, providing reliable technical guarantee for the early closure of the post-casting strip of the underground garage settlement. The preparation and application of this high-performance concrete helps ensure the stability and safety of the post-casting belt under complex geological conditions, reduces the cost of later maintenance, and improves the overall use function and economic benefits of the underground garage. At the same time, the environmental protection characteristics of these materials also meet the requirements of the modern construction industry for green construction and sustainable development.

[0060] In the preparation stage, the present invention cleans the debris in the post-casting zone and roughens it, creating good conditions for pouring concrete. The accuracy of steel bar processing ensures the effective combination of new and old concrete and improves the integrity of the structure. In the later monitoring stage, continuous monitoring provides a guarantee for the long-term safe use of the underground garage, timely discovers and handles safety hazards such as settlement and displacement, and ensures the safety and reliability of the underground garage.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for early closing of the post-casting zone of an underground garage, characterized in that: The method for sealing the post-casting strip of the underground garage in advance comprises the following steps: S1: Conduct investigation and analysis: Conduct a detailed investigation on the settlement of the underground garage to understand the cause, scope and extent of the settlement; analyze the current status of the settlement post-casting belt, including the width, depth and material of the post-casting belt; S2: Formulate a plan: According to the survey results, formulate a plan for early closure of the post-settlement pouring zone; determine the construction process, materials and equipment requirements; S3: Carry out preparation work: clean up the debris in the post-casting belt to ensure that the construction surface is clean and tidy; roughen the concrete on both sides of the post-casting belt to increase the bonding strength of the new and old concrete; S4: Process the steel bars: cut, weld and tie the steel bars in the post-casting zone according to the design plan; ensure that the spacing and diameter of the steel bars meet the design requirements; S5: Set up formwork: Set up formwork on both sides of the post-casting strip. The formwork should have a certain strength and rigidity; ensure that the formwork is tightly spliced ​​to prevent leakage during concrete pouring; S6: An advanced water-stopping concrete belt and a waterproof layer are set at the lower part of the post-cast belt to achieve precipitation and drainage around the foundation pit; S7: Prepare concrete, weigh: high-performance recycled aggregate: 1100-1200 parts by weight; high-efficiency coagulant: 80-100 parts by weight; adjusted water with a pH value of 8-9: 150-200 parts by weight; super-efficient water reducer: 10-50 parts by weight; fine mineral admixture: 50-200 parts by weight; polymer emulsion: silicone-acrylic emulsion: 18-20 parts by weight; silicate early strength agent: 25-35 parts by weight; nano-scale anticorrosive agent: 100-120 parts by weight; glass fiber or carbon fiber: 250-290 parts by weight; nano-silver antibacterial agent: 120-140 parts by weight; supported photocatalytic nanomaterial: 20-40 parts by weight; intelligent shape memory alloy fiber: 20-40 parts by weight; magnetic nanoparticles: 20-50 parts by weight; Then, concrete is prepared using the weighed raw materials; S8: After the concrete pouring is completed, cover and water it in time for curing; the curing time shall not be less than 7 days; S9: After the concrete strength reaches the design requirements, remove the formwork; during the removal process, pay attention to protecting the concrete surface to avoid damage; S10: Check the quality of the sealed post-cast strip, including concrete strength and appearance; if there are any quality problems, take timely measures to rectify them; S11: Regularly monitor the closed post-cast strip and observe its operating conditions; promptly handle any problems found to ensure safe use of the underground garage.

2. A method for early sealing of a post-casting zone of an underground garage according to claim 1, characterized in that: In the step S1, a high-precision level is used to observe the settlement, and the cumulative settlement and settlement rate of each observation point are recorded to ensure that the observation error is less than 1 mm; the physical and mechanical properties of the soil layer are analyzed through the geological survey report, including the compression modulus, Poisson's ratio, and cohesion of the soil; an ultrasonic detector is used to detect the compactness and internal defects of the concrete on both sides of the post-cast strip; the size of the post-cast strip is recorded in detail, the width is 800-1200 mm, the depth should reach at least 300 mm below the foundation bottom plate, and the material includes the strength grade of the concrete and the specification of the steel bar; In the step S2, the best time to close the post-casting strip is determined, which is carried out when the settlement rate is less than 0.01 mm / d; the construction method should specify the segment length, each segment should not exceed 20m, and the skip bin method should be used for construction; the concrete mix design should include a water-cement ratio not exceeding 0.45, a sand ratio of 40%-45%, and a maximum aggregate particle size not exceeding 25mm; the equipment requirements should list in detail the models and quantities of concrete mixers, pump trucks, and vibrators.

3. A method for early closing of a post-casting zone of an underground garage according to claim 1, characterized in that: In step S3, when cleaning the debris in the post-casting strip, a high-pressure water gun should be used to rinse it to ensure that there is no oil stain or loose soil; a professional chiseling machine should be used for the roughening treatment, and the chiseling depth should be controlled at 8-12mm, and the chiseling area should not be less than 75% of the concrete surface; at the same time, the concrete on both sides of the post-casting strip should be polished to remove the loose layer and floating slurry; In step S4, the cutting length of the steel bars should be adjusted according to the specific conditions of the post-casting strip to ensure that the lap length is not less than 35 times the steel bar diameter required by the specification; carbon dioxide gas shielded welding should be used during welding, the weld width should be not less than 8 mm, and the weld height should be not less than 4 mm; when binding, the transverse and longitudinal spacing of the steel bars should be kept uniform, 150 mm and 200 mm respectively.

4. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In the step S5, a phenolic coated board with a thickness of not less than 15 mm or a steel plate with a thickness of not less than 6 mm is selected as the template; The joints of the formwork should be sealed with sealing strips or foam to ensure that the joints are less than 1.5mm; the formwork support system uses adjustable steel pipe brackets, with the spacing between vertical poles not exceeding 1m and the spacing between horizontal poles not exceeding 0.6m to ensure the overall stability of the formwork.

5. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In step S6, the drainage pipe should be made of PVC or HDPE pipe with a diameter of at least 110 mm, and the slope of the pipe should be maintained at more than 1% when laying; the pipe interface should be hot-melt welded, and the welding joint should be smooth and uniform, without cold welds or leaking welds; the area around the pipe should be filled with fine sand or concrete to prevent the pipe from shifting during the pouring process.

6. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In step S7, the preparation method of concrete is as follows: first, accurately weigh high-performance recycled aggregate according to the ratio and put it into a concrete mixer; then, add a high-efficiency coagulant and fine mineral admixture, and start the mixer for preliminary mixing; then, gradually add adjustment water and super-efficient water reducing agent, and continue to stir until the mixture is uniform to ensure that the concrete has good working performance; then, add polymer emulsion and silicate early strength agent to improve the early strength and durability of the concrete; during the stirring process, gradually add nano-scale anti-corrosion agent, glass fiber or carbon fiber and nano-silver antibacterial agent to enhance the anti-corrosion, anti-cracking and antibacterial properties of the concrete; the entire stirring process should continue until all components are completely dispersed and uniform to form a concrete mixture with uniform texture and good fluidity; finally, the mixed concrete is transported to the construction site in time, and poured, vibrated and cured according to the construction requirements to ensure the strength and durability of the concrete structure.

7. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In step S8, during the curing process, the concrete covering material should be wet sacks or wet straw mats, and the thickness of the covering layer should be not less than 20 mm; the frequency of watering should be adjusted according to local climatic conditions, and water should be sprinkled every 2-4 hours to keep the concrete surface moist; during the curing period, a cordon should be set to avoid human damage and vehicle crushing.

8. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In step S9, the concrete strength should be tested by a rebound tester and reach more than 75% of the design strength; when removing the formwork, the formwork that has the greatest impact on the support of the concrete surface should be removed first, and then the other formworks should be gradually removed; during the formwork removal process, the formwork should be gently tapped with a wooden hammer to avoid damage to the concrete surface.

9. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In step S10, the appearance inspection uses a magnifying glass to observe the concrete surface and record the width, length and distribution of the cracks; if there are quality problems, reinforcement measures should include carbon fiber cloth pasting and grouting reinforcement, and the repair material should be the same as the original concrete material.

10. A method for early sealing of a post-casting zone of an underground garage as claimed in claim 1, characterized in that: In step S11, the monitoring cycle should be adjusted according to seasonal changes and groundwater level conditions, and monitoring should be intensified during the rainy season or when the groundwater level rises; the monitoring content includes the settlement, horizontal displacement, and crack development of the post-casting strip, and observations are made using precision levels and total stations; the monitoring data should be recorded in a timely manner and processed through data analysis software, and the emergency plan should be immediately activated when an abnormal situation is found.

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