Construction method for reinforcing soft soil foundation

Abstract

The invention relates to the technical field of civil engineering, in particular to a construction method for reinforcing a soft soil foundation. Comprising the following steps that firstly, prestressed piles are driven into a soft soil layer; filling a high-performance composite material; the foundation performance is enhanced by adopting a multi-layer grouting technology; a protective layer made of a high-strength geogrid and a polyurethane elastic material is laid, so that the pressure of the upper structure is reduced; a monitoring system is arranged to detect settlement and bearing capacity changes in real time, and construction safety and effect are ensured. The prestressed pile technology, the high-performance composite material filling, the multi-layer grouting technology and the protective layer laying technology are combined, an advanced monitoring system is adopted, the change of the foundation can be monitored in real time in the construction process, the reinforcement scheme can be adjusted in time, and the long-term stability and safety of the foundation are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to a construction method for reinforcing a soft soil foundation. Background Art

[0002] The reinforcement of soft soil foundation has always been an important technical challenge in the field of civil engineering. Soft soil usually has the characteristics of high water content, low strength and poor consolidation, which makes the soft soil foundation prone to settlement and deformation when bearing the load of buildings or other structures, affecting the stability and safety of the structure. Therefore, the development of effective soft soil foundation reinforcement technology is crucial to improve the quality of engineering and extend the service life of the structure.

[0003] At present, there are various soft soil foundation reinforcement technologies, mainly including traditional replacement method, drainage consolidation method, deep foundation method and composite foundation reinforcement technology developed in recent years.

[0004] The replacement method increases the bearing capacity of the foundation by excavating the soft soil layer and backfilling it with higher-strength materials (such as sand, gravel, etc.). This method is simple and easy to implement, but it is only suitable for areas with small depths and low groundwater levels. For large-scale or deep soft soil foundations, the replacement method is costly and difficult to construct.

[0005] The drainage consolidation method mainly accelerates the drainage consolidation process of soft soil and improves the foundation strength by setting up drainage channels (such as sand wells, drainage boards, etc.) in the foundation. This method can effectively reduce the settlement of soft soil to a certain extent, but the construction period is long and it is highly dependent on groundwater. It is not effective in areas with high groundwater levels.

[0006] Deep foundation methods such as pile foundations, by driving piles into soft soil layers, transfer the upper load to deeper soil layers with stronger bearing capacity, thereby improving the bearing capacity of the foundation. Pile foundations are widely used in various projects, but there are also problems such as high construction costs and complex construction processes. Especially in foundations with deeper soft soil layers, the construction difficulty and cost of pile foundations will increase significantly.

[0007] In recent years, composite foundation reinforcement technology has gradually become a research hotspot for soft soil foundation reinforcement. This technology combines the advantages of multiple reinforcement methods and comprehensively improves the bearing capacity and stability of the foundation by setting prestressed piles, grouting, and filling high-performance materials in the soft soil layer. Although traditional and emerging soft soil foundation reinforcement technologies have solved the settlement and deformation problems of soft soil foundations to a certain extent, there are still some significant technical defects and limitations.

[0008] (1) Although the traditional replacement and drainage consolidation methods are effective under certain specific conditions, the cost and construction difficulty are significant challenges in large-scale or deep soft soil foundations. The replacement method requires a lot of manpower and material resources for excavation and backfilling operations, while the drainage consolidation method is limited by the groundwater level and construction period, making it difficult to significantly improve the bearing capacity of the foundation in a short period of time.

[0009] (2) Deep foundation methods such as pile foundations, although they are excellent in improving the bearing capacity of foundations, their high construction costs and complex construction processes limit their large-scale application. Especially in foundations with deep soft soil layers, the construction difficulty and cost of pile foundations will increase significantly, and the disturbance of the surrounding soil during the driving of the piles will easily lead to uneven settlement of the foundation. Summary of the invention

[0010] The present invention provides a novel soft soil foundation reinforcement construction method, which combines prestressed pile technology, high-performance composite material filling, multi-layer grouting technology and protective layer laying technology, and adopts an advanced monitoring system. It can monitor the changes of the foundation in real time during the construction process, adjust the reinforcement plan in time, and ensure the long-term stability and safety of the foundation.

[0011] The technical solution adopted by the present invention is: a construction method for reinforcing a soft soil foundation, comprising the following steps:

[0012] Step 1: Use prestressed pile technology to initially reinforce the foundation. By driving prestressed piles into the soft soil layer, the rigidity and friction of the pile body are used to improve the bearing capacity and stability of the foundation.

[0013] Step 2: Fill the space between the prestressed piles with a high-performance composite material, which is a mixture of epoxy resin, cement, nano-silica and multi-walled carbon nanotubes in a specific ratio and has super high bonding strength and durability;

[0014] Step 3: Use multi-layer grouting technology to inject special slurry at different depths around the pile body through the grouting holes on the prestressed pile. The slurry is composed of high modulus polymer, early strength agent and retarder to enhance the filling effect of the composite material between the piles and improve the overall performance of the foundation;

[0015] Step 4: Lay a protective layer composed of high-strength geogrid and polyurethane elastic material on the surface of the foundation. Through the elastic effect of the material, the direct pressure of the upper structure on the soft soil foundation is reduced, and the long-term stability of the foundation is improved;

[0016] Step 5: According to the superstructure load and foundation conditions, set up a monitoring system to regularly detect foundation settlement and bearing capacity changes, and adjust the reinforcement plan in time to ensure construction safety and reinforcement effect.

[0017] As a further improvement of the present invention, the preparation and filling method of the high-performance composite material comprises the following steps:

[0018] S1: Mix epoxy resin, cement, nano-silica and multi-walled carbon nanotubes, and stir them at 1000 rpm for 30 minutes using a high-speed mixer to make them fully uniform;

[0019] S2: Add an appropriate amount of water to the mixture and stir for 10 minutes until the mixture reaches a fluid state;

[0020] S3: The prepared composite material is transported into the gaps between the prestressed piles by means of a pumping device and filled to a predetermined height to ensure the density and uniformity of the material;

[0021] S4: After filling, use a vibrating rod to vibrate the material to remove air bubbles and ensure close contact between the slurry and the pile body.

[0022] As a further improvement of the present invention, the mass ratio of the epoxy resin, cement, nano-silicon dioxide and multi-walled carbon nanotubes is 5:2:0.5:0.1.

[0023] As a further improvement of the present invention, the implementation of the multi-layer grouting technology includes the following steps:

[0024] SS1: Pre-buried grouting holes with a diameter of 32 mm in the prestressed pile, and the grouting holes are evenly arranged along the pile body with a spacing of 1.5 meters;

[0025] SS2: Select high modulus polymer, early strength agent and retarder to mix and prepare a specially formulated slurry. The fluidity requirement of the slurry is 10-15 seconds.

[0026] SS3: Grouting is carried out at different depths of the foundation through grouting holes, and the grouting pressure is controlled at 0.5-1.0 MPa to ensure sufficient diffusion of the slurry;

[0027] SS4: After grouting is completed, close the grouting holes and use sealing materials to prevent slurry backflow to ensure the reinforcement effect.

[0028] As a further improvement of the present invention, the high modulus polymer is one of polyvinyl alcohol, polyacrylate, and polyurethane; the early strength agent is one of calcium chloride and aluminum sulfate; the retarder is one of sodium gluconate and citric acid, and the mass ratio of the high modulus polymer, the early strength agent and the retarder is 1:0.2:0.1.

[0029] As a further improvement of the present invention, the method for laying the protective layer comprises the following steps:

[0030] MS1: Before laying the protective layer, level the foundation surface to ensure that the surface is clean and free of debris, providing a good foundation for laying the protective layer;

[0031] MS2: Cut high-strength geogrids and polyurethane elastic materials according to the shape and size of the foundation to ensure the integrity and adaptability of the materials during laying;

[0032] MS3: According to the design requirements, first lay the high-strength geogrid, and then lay the polyurethane elastic material on it to ensure that the two layers of materials are tightly combined;

[0033] MS4: Use nails and adhesives to fix the geogrid and polyurethane elastic material to the foundation surface to ensure that the material will not be displaced by external forces;

[0034] MS5: After paving is completed, the surface of the protective layer is compacted to ensure the density and uniformity of the material and prevent gaps between the materials;

[0035] MS6: After the protective layer is laid, a comprehensive inspection and acceptance is carried out to ensure that the protective layer meets the design requirements and construction standards and ensures the overall stability and durability of the foundation.

[0036] As a further improvement of the present invention, the monitoring system is composed of a settlement monitoring instrument, a stress sensor, a data collector, and data analysis software. The settlement monitoring instrument is used to monitor the settlement changes of the foundation in real time; the stress sensor is used to measure the stress distribution and changes of the foundation; the data collector is used to collect and transmit monitoring data; the data analysis software is used to analyze and process the monitoring data, generate reports and predict foundation change trends, thereby realizing real-time monitoring and adjustment of the foundation reinforcement effect.

[0037] As a further improvement of the present invention, the settlement monitoring instrument uses a laser rangefinder, an inclinometer, and a vibrating-wire settlement meter, which are installed in the load concentration area and the weak area of ​​the foundation to record the changes in foundation settlement in real time;

[0038] The stress sensor includes a strain gauge and a pressure cell, which is installed on the contact surface between the prestressed pile and the foundation to monitor the stress change between the pile and the foundation;

[0039] The data collector is equipped with a data logger with wireless transmission function, which can collect data from each sensor in real time and transmit it to the central control room through a wireless network;

[0040] The data analysis software is equipped with advanced algorithms that can perform real-time analysis on the collected data, identify potential risk points, and intuitively display them to engineers and construction personnel through a graphical interface.

[0041] As a further improvement of the present invention, the setting and use method of the monitoring system includes the following steps:

[0042] NS1: Before construction, determine the location of monitoring points based on the structural characteristics of the foundation and the load of the superstructure to ensure that the monitoring points can fully cover the key areas of the foundation;

[0043] NS2: Install settlement monitoring instruments and stress sensors to ensure that all equipment is securely fixed to avoid displacement or damage due to construction vibration and external factors;

[0044] NS3: Connect the data collector to the monitoring instrument and set up the wireless transmission network to ensure that the data can be transmitted to the central control room in real time and accurately;

[0045] NS4: Data analysis software is installed in the central control room to analyze and process the real-time data transmitted back and generate real-time reports on foundation settlement and stress changes;

[0046] NS5: Based on the reports provided by the data analysis software, engineers can adjust the construction plan in time and take necessary reinforcement measures to ensure the stability and safety of the foundation;

[0047] NS6: During the construction process, the monitoring system should be inspected and maintained regularly to ensure the accuracy and reliability of the monitoring data and provide continuous technical support for foundation reinforcement.

[0048] Beneficial effects of the present invention: The construction method of the present invention can effectively improve the bearing capacity of soft soil foundation, reduce settlement, and extend the service life of buildings, including the following beneficial effects:

[0049] (1) Significantly improve the bearing capacity and stability of the foundation: The present invention effectively enhances the shear strength and overall stability of the soft soil foundation through the precise filling of high-performance composite materials and the use of multi-layer grouting technology, significantly improving the bearing capacity of the foundation, which helps to reduce the direct pressure of the superstructure on the foundation and ensure the long-term stability and safety of the building.

[0050] (2) Realize real-time monitoring and adjustment of reinforcement effect: The present invention introduces a monitoring system consisting of a settlement monitoring instrument, a stress sensor, a data collector and data analysis software. The system can monitor the settlement changes and stress distribution of the foundation in real time, discover potential risk points in time, and generate reports through data analysis software to provide decision support for engineers. This ensures timely adjustment of the reinforcement plan and guarantees construction safety and reinforcement effect.

[0051] (3) Environmentally friendly and efficient, reducing construction costs: The construction method of the present invention adopts environmentally friendly materials, which reduces environmental pollution during the construction process. At the same time, the steps of preparation and filling of high-performance composite materials and implementation of multi-layer grouting technology have been optimized, which improves construction efficiency and reduces construction costs. In addition, the laying of the protective layer also enhances the foundation's anti-scouring ability, extends the service life of the building, and further improves the economic benefits. DETAILED DESCRIPTION

[0052] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] The present invention provides a construction method for reinforcing a soft soil foundation, comprising the following steps:

[0054] Step 1: Use prestressed pile technology to initially reinforce the foundation. By driving prestressed piles into the soft soil layer, the rigidity and friction of the pile body are used to improve the bearing capacity and stability of the foundation.

[0055] Step 2: Fill the space between the prestressed piles with a high-performance composite material, which is a mixture of epoxy resin, cement, nano-silica and multi-walled carbon nanotubes in a specific ratio and has super high bonding strength and durability;

[0056] Step 3: Use multi-layer grouting technology to inject special slurry at different depths around the pile body through the grouting holes on the prestressed pile. The slurry is composed of high modulus polymer, early strength agent and retarder to enhance the filling effect of the composite material between the piles and improve the overall performance of the foundation;

[0057] Step 4: Lay a protective layer composed of high-strength geogrid and polyurethane elastic material on the surface of the foundation. Through the elastic effect of the material, the direct pressure of the upper structure on the soft soil foundation is reduced, and the long-term stability of the foundation is improved;

[0058] Step 5: According to the superstructure load and foundation conditions, set up a monitoring system to regularly detect foundation settlement and bearing capacity changes, and adjust the reinforcement plan in time to ensure construction safety and reinforcement effect.

[0059] The preparation and filling method of the high-performance composite material in the present invention comprises the following steps: mixing epoxy resin, cement, nano-silica and multi-walled carbon nanotubes, stirring them at 1000 rpm for 30 minutes using a high-speed stirrer to make them fully uniform; adding an appropriate amount of water to the mixture, stirring for 10 minutes until the mixture reaches a flowing state; delivering the prepared composite material to the gap between the prestressed piles through a pumping device, filling it to a predetermined height, and ensuring the density and uniformity of the material; after the filling is completed, vibrating the material with a vibrating rod to remove bubbles and ensure close contact between the slurry and the pile body. Among them, the mass ratio of epoxy resin, cement, nano-silica and multi-walled carbon nanotubes is 5:2:0.5:0.1.

[0060] The implementation of the multi-layer grouting technology in the present invention includes the following steps: pre-embed grouting holes with a diameter of 32 mm in the prestressed pile, and the grouting holes are evenly arranged along the pile body with a spacing of 1.5 meters; select high modulus polymer, early strength agent and retarder to mix, prepare a special slurry, and the fluidity requirement of the slurry is 10-15 seconds; grouting is carried out at different depths of the foundation through the grouting holes, and the grouting pressure is controlled at 0.5-1.0 MPa to ensure that the slurry is fully diffused; after the grouting is completed, the grouting holes are closed, and sealing materials are used to prevent the slurry from flowing back to ensure the reinforcement effect. Among them, the high modulus polymer is one of polyvinyl alcohol, polyacrylate, and polyurethane; the early strength agent is one of calcium chloride and aluminum sulfate; the retarder is one of sodium gluconate and citric acid, and the mass ratio of the high modulus polymer, the early strength agent and the retarder is 1:0.2:0.1.

[0061] The method for laying the protective layer in the present invention comprises the following steps: before laying the protective layer, the surface of the foundation is leveled to ensure that the surface is clean and free of debris, thereby providing a good foundation for laying the protective layer; according to the shape and size of the foundation, the high-strength geogrid and the polyurethane elastic material are cut to ensure the integrity and adaptability of the materials during the laying process; according to the design requirements, the high-strength geogrid is first laid, and then the polyurethane elastic material is laid thereon to ensure that the two layers of materials are tightly combined; the geogrid and the polyurethane elastic material are fixed to the surface of the foundation using nails and adhesives to ensure that the materials will not be displaced due to external forces; after laying, the surface of the protective layer is compacted to ensure the density and uniformity of the material and prevent gaps between the materials; after the protective layer is laid, a comprehensive inspection and acceptance is carried out to ensure that the protective layer meets the design requirements and construction standards and ensures the overall stability and durability of the foundation.

[0062] The monitoring system in the present invention is composed of a settlement monitoring instrument, a stress sensor, a data collector, and a data analysis software. The settlement monitoring instrument is used to monitor the settlement changes of the foundation in real time; the stress sensor is used to measure the stress distribution and changes of the foundation; the data collector is used to collect and transmit monitoring data; the data analysis software is used to analyze and process the monitoring data, generate reports and predict the trend of foundation changes, so as to achieve real-time monitoring and adjustment of the foundation reinforcement effect. The settlement monitoring instrument uses a laser rangefinder, an inclinometer, and a vibrating wire settlement meter, which are installed in the load concentration area and the weak area of ​​the foundation to record the changes in foundation settlement in real time; the stress sensor includes a strain gauge and a pressure box, which are installed on the contact surface between the prestressed pile and the foundation to monitor the stress changes between the pile body and the foundation; the data collector is equipped with a data recorder with a wireless transmission function, which can collect data from each sensor in real time and transmit it to the central control room through a wireless network; the data analysis software has an advanced algorithm, which can analyze the collected data in real time, identify potential risk points, and intuitively display them to engineers and construction personnel through a graphical interface.

[0063] The setting and use method of the monitoring system in the present invention include the following steps: before construction, according to the structural characteristics of the foundation and the upper structure load, determine the location of the monitoring point to ensure that the monitoring point can fully cover the key areas of the foundation; install settlement monitoring instruments and stress sensors to ensure that all equipment is firmly fixed to avoid equipment displacement or damage due to construction vibration and external factors; connect the data collector to the monitoring instrument and set up a wireless transmission network to ensure that the data can be transmitted to the central control room in real time and accurately; set up data analysis software in the central control room to analyze and process the real-time transmitted data to generate a real-time report on foundation settlement and stress changes; according to the report provided by the data analysis software, engineers can adjust the construction plan in time and take necessary reinforcement measures to ensure the stability and safety of the foundation; during the construction process, regularly inspect and maintain the monitoring system to ensure the accuracy and reliability of the monitoring data and provide continuous technical support for foundation reinforcement.

[0064] Example:

[0065] This embodiment describes in detail a practical case of a specific application of the soft soil foundation reinforcement construction method of the present invention. The project is located in a large industrial park on the southeast coast of my country with complex geological conditions. The soft soil layer is thick, has high water content, and has a high groundwater level, which brings great challenges to the construction project. The project requires the construction of a multi-story building in the soft soil area, which places high requirements on the bearing capacity and stability of the foundation.

[0066] (I) Project Overview

[0067] Project location: An industrial park on the southeast coast

[0068] Foundation type: Deep soft soil layer, water content over 40%, high groundwater level

[0069] Building type: multi-storey industrial plant, total construction area 5000 square meters, design load 150kPa

[0070] (II) Construction steps

[0071] Step 1: Prestressed pile construction

[0072] 1. Pile diameter and length: Select prestressed piles with a diameter of 400 mm and a length of 20 m and drive them into the soft soil layer.

[0073] 2. Pile driving equipment: Use a long spiral drilling machine to construct prestressed piles, ensuring that the verticality error of the pile body does not exceed 1%.

[0074] 3. Pile driving sequence: Use the skipping pile construction method to avoid excessive soil disturbance, which may lead to uneven foundation settlement.

[0075] Step 2: High-performance composite material filling

[0076] 1. Material ratio: The mass ratio of epoxy resin, cement, nano-silicon dioxide and multi-walled carbon nanotubes is 5:2:0.5:0.1.

[0077] 2. Mixing and pumping: After mixing the above materials, use a high-speed mixer to stir at 1000 rpm for 30 minutes, then add an appropriate amount of water and stir for 10 minutes until it is fluid. Then use pumping equipment to transport the composite material to the gaps between the prestressed piles and fill it to the predetermined height.

[0078] 3. Vibration treatment: After filling is completed, use a vibrating rod to vibrate the material to remove bubbles and ensure close contact between the material and the pile body.

[0079] Step 3: Multi-layer grouting technology

[0080] 1. Grouting hole setting: Pre-embed grouting holes with a diameter of 32 mm in the prestressed pile, with a spacing of 1.5 meters and evenly distributed on the pile body.

[0081] 2. Slurry preparation: Polyvinyl alcohol is selected as a high modulus polymer, calcium chloride is used as an early strength agent, and sodium gluconate is used as a retarder. The mass ratio of the three is 1:0.2:0.1. The fluidity requirement of the slurry is 10-15 seconds.

[0082] 3. Grouting implementation: Grouting is carried out at different depths of the foundation through grouting holes. The grouting pressure is controlled at 0.6 MPa to ensure sufficient diffusion of the slurry.

[0083] 4. Hole sealing: After grouting is completed, use sealing materials to seal the grouting hole to prevent slurry backflow.

[0084] Step 4: Laying the protective layer

[0085] 1. Foundation surface treatment: Before construction, level the foundation surface to ensure that the surface is clean and free of debris.

[0086] 2. Material cutting: Cut high-strength geogrids and polyurethane elastic materials according to the shape and size of the foundation.

[0087] 3. Laying order: first lay the high-strength geogrid, and then lay the polyurethane elastic material on it, ensuring that the two layers of materials are tightly combined.

[0088] 4. Fixing and compaction: Use nails and adhesives to fix the geogrid and polyurethane elastic material to the foundation surface, and then compact it to ensure the density and uniformity of the material.

[0089] 5. Inspection and acceptance: After laying is completed, a comprehensive inspection and acceptance is carried out to ensure that the protective layer meets the design requirements and construction standards.

[0090] Step 5: Monitoring system settings

[0091] 1. Monitoring point selection: Determine the location of the monitoring points based on the structural characteristics of the foundation and the superstructure load to ensure that the monitoring points can fully cover the key areas of the foundation.

[0092] 2. Instrument installation: Install settlement monitoring instruments such as laser rangefinders, inclinometers, and vibrating-wire settlement meters in the load concentration areas and weak foundation areas of the foundation. Install stress sensors such as strain gauges and pressure cells on the contact surface between the prestressed piles and the foundation.

[0093] 3. Data collection and transmission: Connect the data collector to the monitoring instrument and set up a wireless transmission network to ensure that the data can be transmitted to the central control room in real time and accurately.

[0094] 4. Data analysis: Data analysis software is installed in the central control room to analyze and process the data transmitted in real time and generate real-time reports on foundation settlement and stress changes.

[0095] 5. Plan adjustment: Based on the report provided by the data analysis software, engineers can adjust the construction plan in time and take necessary reinforcement measures to ensure the stability and safety of the foundation.

[0096] 6. Maintenance and inspection: During the construction process, the monitoring system should be inspected and maintained regularly to ensure the accuracy and reliability of the monitoring data.

[0097] (III) Implementation Effect

[0098] 1. Foundation bearing capacity: The bearing capacity of the foundation reinforced by the method of the present invention is significantly improved, reaching the design requirement of 150kPa.

[0099] 2. Settlement control: Monitoring data show that the settlement of the foundation has been effectively controlled, with the maximum settlement not exceeding 10 mm, which meets engineering standards.

[0100] 3. Enhanced stability: The laying of the protective layer effectively reduces the direct pressure of the superstructure on the foundation, and the overall stability of the foundation is significantly enhanced.

[0101] 4. Environmentally friendly and efficient: The high-performance composite materials and slurry used in the construction process are environmentally friendly materials, which reduces environmental pollution. At the same time, the optimized construction process improves efficiency, shortens the construction period and reduces costs.

[0102] (IV) Conclusion

[0103] This embodiment significantly improves the bearing capacity and stability of the foundation, effectively controls settlement, and ensures the safety and durability of the building through the comprehensive application of prestressed piles, high-performance composite material filling, multi-layer grouting technology, and protective layer laying. In addition, the introduction of a real-time monitoring system allows the reinforcement plan to be adjusted in a timely manner during the construction process, ensuring the quality and safety of the construction. This method has a significant application effect under complex geological conditions and has a wide range of promotion value.

[0104] In summary, the construction method for reinforcing the soft soil foundation of the present invention has significant technical advantages and economic benefits, and provides a new solution for construction projects under similar geological conditions. Through the implementation of this method, not only the bearing capacity and stability of the foundation are improved, but also the settlement is effectively controlled, ensuring the long-term safety and durability of the building. At the same time, the environmental protection characteristics of the method meet the requirements of current sustainable development, and the improvement of construction efficiency and the reduction of cost also make it economically competitive. Therefore, the construction method for reinforcing the soft soil foundation of the present invention has important application prospects and promotion value in engineering practice.

[0105] 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 aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for reinforcing a soft soil foundation, characterized in that: The following steps are involved: Step 1: Use prestressed pile technology to initially reinforce the foundation. By driving prestressed piles into the soft soil layer, the rigidity and friction of the pile body are used to improve the bearing capacity and stability of the foundation. Step 2: Fill the space between the prestressed piles with a high-performance composite material, which is a mixture of epoxy resin, cement, nano-silica and multi-walled carbon nanotubes in a specific ratio and has super high bonding strength and durability; Step 3: Use multi-layer grouting technology to inject special slurry at different depths around the pile body through the grouting holes on the prestressed pile. The slurry is composed of high modulus polymer, early strength agent and retarder to enhance the filling effect of the composite material between the piles and improve the overall performance of the foundation; Step 4: Lay a protective layer composed of high-strength geogrid and polyurethane elastic material on the surface of the foundation. Through the elastic effect of the material, the direct pressure of the upper structure on the soft soil foundation is reduced, and the long-term stability of the foundation is improved; Step 5: According to the superstructure load and foundation conditions, set up a monitoring system to regularly detect foundation settlement and bearing capacity changes, and adjust the reinforcement plan in time to ensure construction safety and reinforcement effect.

2. A construction method for reinforcing a soft soil foundation according to claim 1, characterized in that: The preparation and filling method of the high-performance composite material comprises the following steps: S1: Mix epoxy resin, cement, nano-silica and multi-walled carbon nanotubes, and stir them at 1000 rpm for 30 minutes using a high-speed mixer to make them fully uniform; S2: Add an appropriate amount of water to the mixture and stir for 10 minutes until the mixture reaches a fluid state; S3: The prepared composite material is transported into the gaps between the prestressed piles by means of a pumping device and filled to a predetermined height to ensure the density and uniformity of the material; S4: After filling, use a vibrating rod to vibrate the material to remove air bubbles and ensure close contact between the slurry and the pile body.

3. A construction method for reinforcing a soft soil foundation according to claim 2, characterized in that: The mass ratio of the epoxy resin, cement, nano-silicon dioxide and multi-walled carbon nanotubes is 5:2:0.5:0.

1.

4. A construction method for reinforcing a soft soil foundation according to claim 1, characterized in that: The implementation of the multi-layer grouting technology includes the following steps: SS1: Pre-buried grouting holes with a diameter of 32 mm in the prestressed pile, and the grouting holes are evenly arranged along the pile body with a spacing of 1.5 meters; SS2: Select high modulus polymer, early strength agent and retarder to mix and prepare a specially formulated slurry. The fluidity requirement of the slurry is 10-15 seconds. SS3: Grouting is carried out at different depths of the foundation through grouting holes, and the grouting pressure is controlled at 0.5-1.0 MPa to ensure sufficient diffusion of the slurry; SS4: After grouting is completed, close the grouting holes and use sealing materials to prevent slurry backflow to ensure the reinforcement effect.

5. A construction method for reinforcing a soft soil foundation according to claim 4, characterized in that: The high modulus polymer is one of polyvinyl alcohol, polyacrylate, and polyurethane; the early strength agent is one of calcium chloride and aluminum sulfate; the retarder is one of sodium gluconate and citric acid, and the mass ratio of the high modulus polymer, the early strength agent and the retarder is 1:0.2:0.

1.

6. A construction method for reinforcing a soft soil foundation according to claim 1, characterized in that: The method for laying the protective layer comprises the following steps: MS1: Before laying the protective layer, level the foundation surface to ensure that the surface is clean and free of debris, providing a good foundation for laying the protective layer; MS2: Cut high-strength geogrids and polyurethane elastic materials according to the shape and size of the foundation to ensure the integrity and adaptability of the materials during laying; MS3: According to the design requirements, first lay the high-strength geogrid, and then lay the polyurethane elastic material on it to ensure that the two layers of materials are tightly combined; MS4: Use nails and adhesives to fix the geogrid and polyurethane elastic material to the foundation surface to ensure that the material will not be displaced by external forces; MS5: After paving is completed, the surface of the protective layer is compacted to ensure the density and uniformity of the material and prevent gaps between the materials; MS6: After the protective layer is laid, a comprehensive inspection and acceptance is carried out to ensure that the protective layer meets the design requirements and construction standards and ensures the overall stability and durability of the foundation.

7. A construction method for reinforcing a soft soil foundation according to claim 1, characterized in that: The monitoring system consists of a settlement monitoring instrument, a stress sensor, a data collector, and data analysis software. The settlement monitoring instrument is used to monitor the settlement changes of the foundation in real time; the stress sensor is used to measure the stress distribution and changes of the foundation; the data collector is used to collect and transmit monitoring data; the data analysis software is used to analyze and process monitoring data, generate reports and predict foundation change trends, thereby realizing real-time monitoring and adjustment of the foundation reinforcement effect.

8. A construction method for reinforcing a soft soil foundation according to claim 7, characterized in that: The settlement monitoring instrument uses a laser rangefinder, an inclinometer, and a vibrating-wire settlement meter, which are installed in the load concentration area and the weak area of ​​the foundation to record the changes in foundation settlement in real time; The stress sensor includes a strain gauge and a pressure cell, which is installed on the contact surface between the prestressed pile and the foundation to monitor the stress change between the pile and the foundation; The data collector is equipped with a data logger with wireless transmission function, which can collect data from each sensor in real time and transmit it to the central control room through a wireless network; The data analysis software is equipped with advanced algorithms that can perform real-time analysis on the collected data, identify potential risk points, and intuitively display them to engineers and construction personnel through a graphical interface.

9. A construction method for reinforcing a soft soil foundation according to claim 8, characterized in that: The setting and use method of the monitoring system includes the following steps: NS1: Before construction, determine the location of monitoring points based on the structural characteristics of the foundation and the load of the superstructure to ensure that the monitoring points can fully cover the key areas of the foundation; NS2: Install settlement monitoring instruments and stress sensors to ensure that all equipment is securely fixed to avoid displacement or damage due to construction vibration and external factors; NS3: Connect the data collector to the monitoring instrument and set up the wireless transmission network to ensure that the data can be transmitted to the central control room in real time and accurately; NS4: Data analysis software is installed in the central control room to analyze and process the real-time data transmitted back and generate real-time reports on foundation settlement and stress changes; NS5: Based on the reports provided by the data analysis software, engineers can adjust the construction plan in time and take necessary reinforcement measures to ensure the stability and safety of the foundation; NS6: During the construction process, the monitoring system should be inspected and maintained regularly to ensure the accuracy and reliability of the monitoring data and provide continuous technical support for foundation reinforcement.