A green and efficient underground continuous wall deep foundation pit supporting structure and method

Abstract

The application discloses a kind of green efficient underground continuous wall deep foundation pit support structure and method, it is related to underground engineering construction technical field, including guide wall system, trenching system, wall system and monitoring system, the guide wall system includes two concrete guide walls of symmetrical arrangement, the inside of concrete guide wall is equipped with guide groove, the trenching system includes hydraulic grab, mud circulating device and waste slurry processing device, the wall system includes reinforcing cage and environmental protection concrete, the monitoring system includes stress sensor and displacement monitoring point.The application uses environmental protection concrete by concrete guide wall, and by mixing 30% fly ash or using recycled aggregate, reduces the amount of cement, reduces carbon emission to 18%, while matching mud circulating treatment system, makes mud recovery rate exceed 90%, waste slurry discharge reduces 85%, greatly reduces environmental pollution in construction process, realizes the efficient cyclic utilization of resources, ensures that support structure is safe and reliable by monitoring system.

Description

Technical Field

[0001] This invention relates to the field of underground engineering construction technology, and in particular to a green and efficient deep foundation pit support structure and method for underground continuous wall. Background Technology

[0002] With the acceleration of urbanization, the development and utilization of underground space is becoming increasingly widespread, leading to a continuous increase in the number and scale of deep foundation pit projects. Traditional deep foundation pit support technologies, such as pile support and soil nailing wall support, can no longer meet the environmental protection and efficiency requirements of modern engineering. In recent years, diaphragm wall technology has gradually become the mainstream technology for deep foundation pit support due to its advantages such as good integrity, high rigidity, and good water-stopping effect. However, existing diaphragm wall construction still suffers from problems such as mud pollution, high energy consumption, and low construction efficiency, necessitating a more green and efficient construction method and structure.

[0003] Currently, the main methods for constructing diaphragm walls include hydraulic grab trenching and milling trenching. Hydraulic grab trenching is simple and low-cost, but suffers from poor trenching accuracy and low efficiency. Milling trenching produces high-quality trenches, but requires expensive equipment and consumes a lot of energy. Regarding wall materials, ordinary concrete or reinforced concrete are commonly used, with little consideration for environmental performance. The support structure is often a single wall, lacking design considerations for the coordinated protection of the surrounding environment.

[0004] Existing diaphragm wall construction methods suffer from problems such as large mud discharge, severe noise pollution, high energy consumption, and low construction efficiency. At the same time, the support structure is of a single type, which cannot effectively adapt to complex geological conditions and lacks protection measures for surrounding buildings and underground pipelines. Therefore, it is necessary to design a green and efficient diaphragm wall deep foundation pit support structure to solve the above-mentioned problems. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a green and efficient deep foundation pit support structure and method for continuous underground walls, thereby solving the problems in the aforementioned technical solutions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a green and efficient underground continuous wall deep foundation pit support structure, comprising a guide wall system, a trenching system, a wall system, and a monitoring system. The guide wall system comprises two symmetrically arranged concrete guide walls, with guide grooves provided on the inner side of the concrete guide walls. The trenching system comprises a hydraulic grab bucket, a mud circulation device, and a waste slurry treatment device. The wall system comprises a steel cage and environmentally friendly concrete. The monitoring system comprises stress sensors and displacement monitoring points. The hydraulic grab bucket is used for trenching operations along the guide groove. The steel cage is placed into the guide groove by hoisting equipment. The concrete guide wall is made of environmentally friendly concrete and is cast into a continuous wall by tremie pipe method. The mud circulation device is used to maintain the stability of the trench wall and to purify the mud. The monitoring system is used to provide real-time feedback on the status of the support structure.

[0007] Furthermore, the hydraulic grab bucket is of model SG70 with a width of 800mm; the main reinforcement of the steel cage is HRB400 grade steel with a diameter of 25mm; and the environmentally friendly concrete is C30 concrete with 30% fly ash.

[0008] Furthermore, the hydraulic grab bucket can be replaced by a trenching machine, the environmentally friendly concrete can be replaced by recycled aggregate concrete, prestressed anchor cables are added to the wall system to improve the overall stability of the support structure, and the concrete guide wall adopts a prefabricated structure.

[0009] A green and efficient support method for deep foundation pits with diaphragm walls, applied to the aforementioned green and efficient diaphragm wall support structure for deep foundation pits, includes the following support methods: S1. Surveying and Setting Out: Using a high-precision total station surveying instrument, combined with geographic information system data and construction drawings, the positions of the two symmetrically set concrete guide walls in the guide wall system are accurately determined. At the same time, on the construction site, white lime is used to clearly set out the lines along the survey marks, and a laser setting out device is used for verification and calibration to ensure that the setting out error is controlled within a very small range and to ensure the accuracy of subsequent construction. S2. Guide Wall Construction and Curing: The guide wall is constructed using precast concrete slabs. During production, high-precision molds and automated vibration equipment are used to strictly control the dimensional accuracy within ±2mm. The concrete strength is prepared according to the design strength grade increased by 5%, ensuring its strength is ≥97% of the preset value. After transportation to the site, large cranes are used in conjunction with professional construction personnel for assembly. Assembly is carried out strictly according to the design layout, ensuring uniform and consistent joints between precast slabs. The joints are sealed with high-strength waterproof mortar, with the coating thickness controlled at 5-8mm to ensure a good seal. After assembly, geotextile is promptly covered and watered for moisturizing and curing for no less than 7 days to allow it to reach the design strength. S3. Trenching Operation and Slurry Treatment: A stable hydraulic grab bucket is selected for trenching operations along the guide channel. Before operation, the hydraulic grab bucket is fully tested to ensure that all performance indicators meet the construction requirements. Simultaneously, the slurry circulation system is activated. The slurry circulation system includes a slurry tank, a slurry pump, and slurry delivery pipelines. The slurry tank is divided into a sedimentation tank and a storage tank. Through reasonable zoning design, the sedimentation and storage effects of the slurry are guaranteed. The slurry is transported to the trenching area via the slurry pump and delivery pipelines. The liquid column pressure of the slurry maintains the stability of the trench wall. The density, viscosity, and other performance parameters of the slurry are monitored. Real-time monitoring and recording ensure that the mud performance meets construction requirements; the waste mud treatment device uses advanced centrifugal separation technology to purify the mud, and the purified mud meets the reuse standards, ensuring that the mud can be reused; when encountering hard strata, a trenching machine is promptly used for trenching operations. The milling speed of the trenching machine is controlled at 20-30 rpm, and the speed is adjusted in real time through an automatic control system to ensure milling efficiency and quality; at the same time, mud lubrication is injected synchronously through a dedicated mud injection system to ensure the smooth progress of trenching operations; S4. Trench Section Acceptance and Reinforcing Cage Placement: After trenching is completed, in accordance with standards and specifications, a professional testing tool, including an ultrasonic wall gauge and a steel tape measure, is used to comprehensively inspect key indicators such as verticality, depth, and width of the trench section. The verticality error is controlled within 0.3%, the depth error within ±50mm, and the width error within ±20mm. After acceptance, a professional large crawler crane with special lifting equipment is used to place the reinforcing cage into the trench. The reinforcing cage is manufactured using high-precision molds at the processing site, and automated welding equipment is used to ensure that the geometric dimensions of the reinforcing cage and the spacing of the reinforcing bars meet the design requirements, with the spacing error controlled within ±5mm. During the placement process, multiple reinforcement support points are set on the reinforcing cage, and steel sections or steel pipes are used for reinforcement. S5. Environmentally friendly concrete pouring: Environmentally friendly concrete is poured into the trench using a tremie pipe method. The environmentally friendly concrete is C30 concrete with 30% fly ash or recycled aggregate concrete. Before pouring, the tremie pipe is tested for sealing and strength. During pouring, the tremie pipe is strictly buried in the concrete to a depth of not less than 2m. The pouring speed and tremie pipe lifting speed are dynamically adjusted through a real-time concrete pouring monitoring system to ensure the compactness of the concrete pouring and prevent quality problems such as broken piles and mud inclusions, thus forming a continuous wall. S6. Monitoring System Installation: Stress sensors and displacement monitoring points are rationally arranged around the continuous wall and foundation pit according to design requirements. High-precision vibrating wire stress gauges are used for stress sensors, and high-precision total stations are used for displacement monitoring points with reflectors. A real-time monitoring data acquisition and transmission system is established to transmit monitoring data to the monitoring center in real time. The data is then processed and analyzed using professional data analysis software to monitor the stress and displacement of the support structure in real time. When the stress monitoring data exceeds the warning value or the displacement change rate is abnormal, the emergency plan is immediately activated, and corresponding measures such as increasing support and backfilling earth are taken to ensure the safety of the foundation pit. S7. Installation of sonic logging pipes: During the fabrication of the reinforcing cage, sonic logging pipes are installed simultaneously. The sonic logging pipes are made of high-quality metal, and their diameter and wall thickness meet relevant testing standards. The installation position of the sonic logging pipes is accurate, and welding or sleeve connection is used to ensure a firm connection without leakage. The top and bottom of the sonic logging pipes are sealed to prevent foreign matter from entering the pipes, which are used for subsequent ultrasonic testing of the quality of the wall concrete. S8. Dynamic Adjustment of Construction: During the excavation of the foundation pit, the stability of the foundation pit is evaluated in real time based on the stress and displacement data of the support structure fed back by the monitoring system and in conjunction with finite element analysis software. Based on the evaluation results, construction parameters such as excavation speed, excavation sequence, and support setting time are adjusted in a timely manner to reasonably arrange the construction schedule and ensure the safety of the foundation pit and its surrounding environment. At the same time, an information feedback mechanism is established during the construction process, and construction personnel and monitoring personnel maintain close communication to promptly resolve problems that arise during construction.

[0010] Furthermore, in step S2, the construction and maintenance of the guide wall, the raw materials for the precast concrete slabs are strictly inspected during factory production. High-quality cement, well-graded aggregates, and high-efficiency water-reducing agents are used to ensure the workability and durability of the concrete. Multiple quality inspection processes are set up on the production line to test the appearance quality, dimensional accuracy, and concrete strength of each precast slab. During transportation, a special transport frame is used to fix the precast slabs to prevent collision damage during transportation. After arriving at the construction site, the precast slabs undergo a second inspection to ensure that they have not been damaged during transportation.

[0011] Furthermore, in step S3, the trenching operation and mud treatment, the volume of the mud tank is rationally designed according to the trenching scale and construction progress. An overflow wall and a guide channel are set between the sedimentation tank and the storage tank to ensure that the mud is fully settled in the sedimentation tank before flowing into the storage tank. The mud pump is selected according to the trenching depth, mud conveying distance, and flow rate requirements to ensure that the mud can be delivered to the trenching site in a timely and stable manner. The mud conveying pipeline uses high-strength and corrosion-resistant pipe materials, and the pipe connection parts use quick couplings with good sealing performance to prevent mud leakage. The mud circulation device is regularly maintained and serviced, the sediment in the mud tank is cleaned, and the operating status of the mud pump and the mud conveying pipeline is checked to ensure their normal operation.

[0012] Furthermore, in step S4, the acceptance of the trench section and the hoisting of the reinforcing cage, a dedicated quality inspection area is set up at the reinforcing cage processing site to conduct a comprehensive inspection of the completed reinforcing cage, including the specifications, quantity, spacing, and welding quality of the reinforcing bars; non-destructive testing equipment is used to conduct random inspections of the welded joints of the reinforcing cage to ensure that the welding quality meets the requirements; when hoisting the reinforcing cage, the crane model and lifting tools are reasonably selected according to the length and weight of the reinforcing cage, and a detailed hoisting plan is formulated; multiple lifting points are set on the reinforcing cage, and auxiliary equipment such as balance beams are used to ensure that the reinforcing cage remains balanced during hoisting and to avoid twisting and deformation.

[0013] Furthermore, in step S6, during the installation of the monitoring system, the emergency plan includes a detailed emergency response process and division of responsibilities, clearly defining the handling measures for different emergency situations. When the stress monitoring data exceeds the warning value, the excavation work of the foundation pit is immediately stopped, and professional technicians are organized to analyze the monitoring data and determine the stability of the support structure. Based on the analysis results, measures such as increasing the number of supports, changing the support type, or strengthening the support stiffness are taken. When the displacement change rate is abnormal, the displacement monitoring points are first checked to eliminate monitoring errors. If the displacement is confirmed to be abnormal, the surrounding buildings and underground pipelines are promptly investigated to assess the impact on the surrounding environment. Based on the assessment results, measures such as backfilling and unloading are taken to control the further development of displacement and ensure the safety of the foundation pit and the surrounding environment. At the same time, the emergency plan is regularly drilled and revised to ensure its effectiveness and operability.

[0014] In summary, this invention provides a green and efficient deep foundation pit support structure and method for continuous underground walls, which has the following beneficial effects: 1. The concrete guide wall uses environmentally friendly concrete and reduces cement usage by adding 30% fly ash or using recycled aggregate, thus reducing carbon emissions by 18%. At the same time, it is equipped with a mud recycling system, which makes the mud recycling rate exceed 90% and reduces waste mud discharge by 85%, greatly reducing environmental pollution during construction and achieving efficient recycling of resources.

[0015] 2. By comprehensively optimizing the construction process, from prefabricating guide walls in the factory to shorten on-site construction time, to selecting high-performance hydraulic grabs, milling machines and other equipment, and reasonably matching mud circulation devices, a series of precise optimizations have significantly improved construction efficiency by more than 20%, effectively shortening the construction period, reducing manpower and material costs, and improving the overall benefits of the project.

[0016] 3. The monitoring system utilizes a high-precision vibrating wire stress gauge to monitor stress, achieving an accuracy of 0.1%. Combined with displacement monitoring points, the resolution reaches 0.5 mm. Data is collected, transmitted, and analyzed in real time. In the event of any anomaly, an early warning is issued and an emergency plan is activated to ensure the safety and reliability of the support structure.

[0017] 4. For complex geological conditions, flexible trenching equipment is used, along with a scientific construction parameter adjustment mechanism. At the same time, timely evaluation and adjustment are made based on monitoring data during construction, effectively protecting surrounding buildings and underground pipelines, and possessing broad geological adaptability and environmental friendliness. Detailed Implementation Example

[0018] This invention provides a technical solution: a green and efficient underground continuous wall deep foundation pit support structure, including a guide wall system, a trenching system, a wall system and a monitoring system. The guide wall system includes two symmetrically arranged concrete guide walls, with guide grooves provided on the inner side of the concrete guide walls. The trenching system includes a hydraulic grab bucket, a mud circulation device and a waste slurry treatment device. The wall system includes a steel cage and environmentally friendly concrete. The monitoring system includes stress sensors and displacement monitoring points. Hydraulic grab buckets are used for trenching operations along guide channels. Reinforcing cages are lowered into the guide channels using hoisting equipment. Environmentally friendly concrete guide walls are cast using a tremie pipe method to form a continuous wall. The prefabricated structure design of the guide wall system significantly improves construction efficiency and reduces on-site wet work pollution. A mud circulation device maintains trench wall stability, achieving a mud recovery rate of over 90%, reducing resource consumption, and simultaneously purifying the mud. A monitoring system provides real-time feedback on the support structure's status, achieving a stress monitoring accuracy of 0.1% and a displacement monitoring resolution of 0.5mm, providing real-time warnings of potential safety hazards. The overall structural rigidity is increased by 25% compared to traditional support systems, making it suitable for ultra-deep foundation pits exceeding 20m.

[0019] The hydraulic grab bucket is model SG70, with a width of 800mm; the main reinforcement of the steel cage uses HRB400 grade steel bars with a diameter of 25mm; the environmentally friendly concrete uses C30 concrete with 30% fly ash, achieving a fly ash replacement rate of 30% and reducing carbon emissions by more than 18%; the SG70 model hydraulic grab bucket, combined with the 800mm wide design, achieves a trenching efficiency of 15m³ / h, a 40% improvement over conventional equipment; the amount of HRB400 grade steel bars used is reduced by 12% while the load-bearing capacity is increased by 20%; the C30 fly ash concrete achieves a 28-day strength of 42MPa, a permeability grade of P12, and a 35% improvement in durability.

[0020] Hydraulic grabs can be replaced by trenching machines, and environmentally friendly concrete can be replaced by recycled aggregate concrete. Prestressed anchors are added to the wall system to improve the overall stability of the support structure. The concrete guide wall adopts a prefabricated structure. The trenching machine is equipped with an automatic speed adjustment system, and the trenching efficiency in hard rock strata reaches 3m / h, which is 3 times that of traditional methods. Recycled aggregate concrete utilizes construction waste, increasing resource utilization by 60%. Prestressed anchors reduce the horizontal displacement of the support structure by 40%. The installation error of the prefabricated guide wall is controlled within ±2mm, and the construction cycle is shortened by 40%.

[0021] A green and efficient support method for deep foundation pits with diaphragm walls, applied to the aforementioned green and efficient diaphragm wall support structure for deep foundation pits, includes the following support methods: S1. Surveying and Setting Out: Utilizing a high-precision total station, combined with geographic information system data and construction drawings, the positions of the two symmetrically arranged concrete guide walls in the guide wall system are accurately determined. Simultaneously, on the construction site, white lime is used to clearly mark the lines along the survey markers, and a laser line-setting device is used for verification and calibration to ensure that the line-setting error is controlled within a minimal range, guaranteeing the accuracy of subsequent construction. The high-precision total station, combined with geographic information system data and construction drawings, can accurately locate the guide wall positions with minimal error; the white lime marking and laser line-setting device verification and calibration further ensure positioning accuracy. This not only reduces rework caused by positioning deviations in subsequent construction, saving manpower, material resources, and time costs, but also lays a solid foundation for the stability of the entire deep foundation pit support structure, ensuring smooth connection of subsequent procedures, improving construction efficiency and quality, and making the overall construction process more controllable.

[0022] S2. Guide Wall Construction and Maintenance: Precast concrete slabs are used for guide wall assembly. During production, high-precision molds and automated vibration equipment are employed to strictly control dimensional accuracy within ±2mm. The concrete strength is prepared at 5% above the design strength grade, ensuring its strength is ≥97% of the preset value. After transportation to the site, large cranes are used in conjunction with professional construction personnel for assembly. Assembly strictly follows the design layout, ensuring uniform joints between precast slabs. Joints are sealed with high-strength waterproof mortar, with a thickness controlled at 5-8mm to ensure effective sealing. After assembly, geotextile is promptly covered and watered for at least 7 days to ensure it reaches the design strength. The precast concrete slabs utilize high-precision molds and automated vibration equipment to guarantee dimensional accuracy and strength. On-site assembly is performed according to the design layout, and joints are sealed. Watering and curing further enhance the guide wall's stability and waterproofing. High-strength waterproof mortar sealing and at least 7 days of curing reduce the risk of leakage and extend the guide wall's service life. Simultaneously, the precast slab production and assembly process reduces on-site wet work, lowers environmental pollution, improves the environmental friendliness and efficiency of construction, and ensures safety and stability in the early stages of foundation pit construction.

[0023] S3. Trenching Operation and Slurry Treatment: A stable hydraulic grab bucket is selected for trenching operations along the guide channel. Before operation, the hydraulic grab bucket is fully tested to ensure that all performance indicators meet the construction requirements. Simultaneously, the slurry circulation system is activated. This system includes a slurry tank, a slurry pump, and slurry delivery pipelines. The slurry tank is divided into a sedimentation tank and a storage tank. Through reasonable zoning design, the sedimentation and storage effects of the slurry are guaranteed. The slurry is transported to the trenching area via the slurry pump and delivery pipelines. The liquid column pressure of the slurry is used to maintain the stability of the trench wall. The density, viscosity, and other performance parameters of the slurry are monitored and recorded in real time to ensure that the slurry performance meets the construction requirements. The waste slurry treatment device uses advanced centrifugal separation technology to process the slurry. The purification process ensures that the purified mud meets reuse standards, guaranteeing its reusability. When encountering hard strata, a trenching machine is promptly used for trenching operations. The milling speed of the trenching machine is controlled at 20-30 rpm, with the speed adjusted in real-time by an automatic control system to ensure milling efficiency and quality. Simultaneously, a dedicated mud injection system injects mud for lubrication, ensuring smooth trenching operations. The hydraulic grab bucket is then put into operation after adjustment. A mud circulation device maintains the stability of the trench walls and purifies the mud. A waste mud treatment device allows for mud reuse, conserving resources. The use of a trenching machine with real-time speed adjustment in conjunction with the mud injection system ensures trenching quality and efficiency. A rationally designed mud pit and suitable equipment selection guarantee a stable mud supply. Regular equipment maintenance reduces malfunctions, enabling continuous and efficient trenching construction, lowering construction costs, and improving the overall construction progress.

[0024] S4. Trench Section Acceptance and Reinforcing Cage Placement: After trenching is completed, in accordance with standards and specifications, a comprehensive acceptance inspection of key indicators such as verticality, depth, and width of the trench section is conducted using ultrasonic wall gauges and steel tape measures. Verticality error is controlled within 0.3%, depth error within ±50mm, and width error within ±20mm. After acceptance, a professional large crawler crane with specialized lifting equipment is used to place the reinforcing cage into the trench. The reinforcing cage is fabricated using high-precision molds at the processing site, and automated welding equipment is used to ensure that the geometric dimensions and spacing of the reinforcing cage meet design requirements, with spacing error controlled within ±5mm. During placement, multiple reinforcement support points are set on the reinforcing cage, reinforced with structural steel or steel pipes. Strict trench section acceptance standards ensure that the trenching quality meets standards. Ultrasonic wall gauges and steel tape measures are used to inspect verticality, depth, and width to ensure the trench section meets design requirements. The reinforcing cage is fabricated using high-precision jigs and undergoes comprehensive inspection. During hoisting, appropriate equipment and reinforcement measures are selected to avoid deformation. This allows for precise installation of the rebar cage, ensuring a tight fit with the trench section, enhancing the overall load-bearing capacity of the wall, reducing potential quality issues caused by rebar cage installation problems, and improving the stability and safety of the diaphragm wall.

[0025] S5. Environmentally Friendly Concrete Pouring: Environmentally friendly concrete, specifically C30 concrete with 30% fly ash or recycled aggregate concrete, is poured into the trench using the tremie pipe method. Before pouring, the tremie pipe undergoes sealing and strength testing. During pouring, the tremie pipe is strictly embedded in the concrete to a depth of no less than 2 meters. A real-time concrete pouring monitoring system dynamically adjusts the pouring speed and tremie pipe lifting speed to ensure the compactness of the concrete and prevent quality problems such as broken piles and mud inclusions, thus forming a continuous wall. Using the tremie pipe method for pouring environmentally friendly concrete, with prior testing of the tremie pipe and control of the pouring depth and dynamic speed adjustment, ensures concrete compactness and effectively prevents problems such as broken piles and mud inclusions. The addition of 30% fly ash or the use of recycled aggregate concrete not only meets strength requirements but also achieves comprehensive resource utilization, reducing costs and environmental impact. The high-quality formation of the continuous wall provides reliable protection for the foundation pit support, improves the durability and stability of the support structure, and ensures the safety of foundation pit construction.

[0026] S6. Monitoring System Installation: Stress sensors and displacement monitoring points are rationally arranged around the continuous wall and foundation pit according to design requirements. High-precision vibrating wire stress gauges are used for stress sensors, and reflectors are used in conjunction with high-precision total stations for displacement monitoring. A real-time monitoring data acquisition and transmission system is established to transmit monitoring data to the monitoring center in real time. This data is processed and analyzed using professional data analysis software to monitor the stress and displacement of the support structure in real time. When stress monitoring data exceeds the warning value or the displacement change rate is abnormal, the emergency plan is immediately activated, and corresponding measures such as increasing support and backfilling are taken to ensure the safety of the foundation pit. The rational arrangement of stress sensors and displacement monitoring points, along with real-time data acquisition and analysis, enables timely detection of abnormalities in the support structure. After an early warning, the emergency plan is activated, and corresponding measures are taken to ensure the safety of the foundation pit. High-precision monitoring equipment and a comprehensive emergency mechanism can prevent accidents in advance, reduce the impact on the surrounding environment, and protect the safety of surrounding buildings and underground pipelines. Regular drills and revisions of the emergency plan enhance emergency response capabilities, ensuring that foundation pit construction is always in a safe and controllable state.

[0027] S7. Installation of Sonic Logging Pipes: Sonic logging pipes are installed simultaneously during the fabrication of the reinforcing cage. These pipes are made of high-quality metal, with diameters and wall thicknesses conforming to relevant testing standards. The installation positions of the logging pipes are accurate, and welding or sleeve connections are used to ensure a secure connection without leakage. The top and bottom of the logging pipes are sealed to prevent debris from entering. These pipes are used for subsequent ultrasonic testing of the wall concrete quality. The simultaneous installation of high-quality metal sonic logging pipes during reinforcing cage fabrication ensures accurate positioning, secure connections, and good sealing, facilitating subsequent ultrasonic testing of the wall concrete quality. Accurate testing can promptly detect internal defects in the concrete, allowing for remedial measures and ensuring wall quality. This helps improve the overall performance of the diaphragm wall, avoids structural hazards caused by concrete quality problems, enhances the reliability of the support structure, and extends the service life of the foundation pit support facilities.

[0028] S8. Dynamic Adjustment of Construction: During the excavation of the foundation pit, the stability of the foundation pit is assessed in real time based on the stress and displacement data of the support structure fed back by the monitoring system, combined with finite element analysis software. Based on the assessment results, construction parameters, such as excavation speed, excavation sequence, and support installation time, are adjusted promptly to rationally arrange the construction schedule and ensure the safety of the foundation pit and its surrounding environment. Simultaneously, an information feedback mechanism is established during the construction process, with close communication between construction and monitoring personnel to promptly resolve problems that arise. The real-time assessment of foundation pit stability based on monitoring data and finite element analysis software, along with timely adjustments to construction parameters, optimizes the construction process. This mechanism ensures a reasonable construction schedule and guarantees the safety of the foundation pit and its surrounding environment. The close communication and feedback mechanism between construction and monitoring personnel allows for rapid resolution of construction problems, reduces construction delays, and improves construction efficiency. Dynamic adjustments enable the rational allocation of construction resources, ensuring the safe, efficient, and orderly progress of foundation pit construction.

[0029] In step S2, during the construction and curing of the guide wall, the precast concrete slabs undergo rigorous raw material inspection during factory production. High-quality cement, well-graded aggregates, and high-efficiency water-reducing agents are used to ensure the workability and durability of the concrete. Multiple quality inspection processes are implemented on the production line to test the appearance quality, dimensional accuracy, and concrete strength of each precast slab. During transportation, a dedicated transport frame is used to secure the precast slabs and prevent damage from collisions. Upon arrival at the construction site, the precast slabs undergo a second inspection to ensure they were not damaged during transportation. The rigorous raw material inspection and multiple quality inspection processes during factory production guarantee the quality of the precast slabs. The dedicated transport frame and on-site secondary inspection prevent damage during transportation, ensuring the quality of the precast slabs used in construction. This effectively improves the construction quality of the guide wall, reduces defects caused by precast slab quality issues, enhances the stability and load-bearing capacity of the guide wall, and thus ensures the smooth progress of the initial construction of the entire deep foundation pit support structure, reducing later maintenance costs.

[0030] In step S3, during trenching and mud treatment, the volume of the mud pit is rationally designed based on the trenching scale and construction progress. An overflow wall and a guide channel are installed between the sedimentation tank and the storage tank to ensure that the mud is fully settled in the sedimentation tank before flowing into the storage tank. The mud pump selection is based on the trenching depth, mud delivery distance, and flow rate requirements to ensure timely and stable delivery of mud to the trenching site. High-strength, corrosion-resistant pipes are used in the conveying pipelines, and quick-connect fittings with good sealing performance are used at pipe connections to prevent mud leakage. Regular maintenance and upkeep of the mud circulation system are performed, including cleaning sediment from the mud pit and checking the operation of the mud pumps and conveying pipelines to ensure normal operation. A rationally designed mud pit volume, optimized internal structure, suitable mud pump selection, high-quality materials and sealing joints in the conveying pipelines, and regular maintenance of the mud circulation system ensure stable mud performance and reliable supply, providing favorable conditions for trenching operations, reducing the risk of trench wall collapse, and improving trenching quality and efficiency. At the same time, it effectively avoids mud leakage and environmental pollution, ensures the cleanliness of the construction site, ensures safe and orderly construction, and improves overall construction efficiency.

[0031] In step S4, during the acceptance of the trench section and the placement of the rebar cage, a dedicated quality inspection area is set up at the rebar cage processing site to conduct a comprehensive inspection of the completed rebar cages, including the specifications, quantity, spacing, and welding quality of the rebars. Non-destructive testing equipment is used to randomly inspect the welded joints of the rebar cages to ensure that the welding quality meets requirements. When placing the rebar cages, the appropriate crane model and lifting equipment are selected based on the length and weight of the rebar cages, and a detailed lifting plan is developed. Multiple lifting points are set up on the rebar cages, and auxiliary equipment such as balance beams are used to ensure that the rebar cages remain balanced during lifting, avoiding twisting and deformation. A dedicated inspection area is set up at the rebar cage processing site to comprehensively inspect the rebar cages and randomly inspect the welding quality to ensure that the rebar cages are of qualified quality. During lifting, the appropriate selection of cranes and lifting equipment, the development of a plan, and the setting of multiple lifting points ensure the balanced lifting of the rebar cages. This effectively prevents deformation and damage to the rebar cages during lifting, ensuring accurate installation, improving the structural strength and stability of the diaphragm wall, guaranteeing the foundation pit support effect, and reducing construction risks.

[0032] During the installation of the monitoring system in step S6, the emergency plan includes a detailed emergency response process and division of responsibilities, clearly defining the handling measures for different emergency situations. When stress monitoring data exceeds the warning value, the excavation work of the foundation pit is immediately stopped, and professional technicians are organized to analyze the monitoring data and determine the stability of the support structure. Based on the analysis results, measures such as increasing the number of supports, changing the support type, or strengthening the support stiffness are taken. When the rate of displacement change is abnormal, the displacement monitoring points are first checked to eliminate monitoring errors. If the displacement is confirmed to be abnormal, the surrounding buildings and underground pipelines are promptly investigated to assess the impact on the surrounding environment. Based on the assessment results, measures such as backfilling and unloading are taken to control the further development of displacement and ensure the safety of the foundation pit and the surrounding environment. At the same time, the emergency plan is regularly drilled and revised to ensure its effectiveness and operability. The detailed emergency plan process and division of responsibilities enable a rapid response in the event of stress or displacement anomalies. Data is analyzed in a timely manner and targeted measures are taken to investigate the impact on the surrounding environment. Regular drills and revisions of the plan ensure that the emergency measures are effective and feasible. This can minimize the construction risks of the foundation pit, ensure the safety of the foundation pit and the surrounding environment, and reduce the losses caused by accidents. A comprehensive emergency response system provides safety assurance for foundation pit construction, enhances the sense of security for construction workers and surrounding residents, and maintains construction order.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A green and efficient underground continuous wall deep foundation pit support structure, comprising a guide wall system, a trenching system, a wall system, and a monitoring system, characterized in that: The guide wall system includes two symmetrically arranged concrete guide walls, with guide grooves provided on the inner side of the concrete guide walls. The trenching system includes a hydraulic grab bucket, a mud circulation device, and a waste slurry treatment device. The wall system includes a steel cage and environmentally friendly concrete. The monitoring system includes stress sensors and displacement monitoring points. The hydraulic grab bucket is used for trenching operations along the guide groove. The steel cage is placed into the guide groove by hoisting equipment. The concrete guide wall is made of environmentally friendly concrete and is cast into a continuous wall by tremie pipe method. The mud circulation device is used to maintain the stability of the trench wall and to purify the mud. The monitoring system is used to provide real-time feedback on the status of the support structure.

2. The green and efficient underground continuous wall deep foundation pit support structure according to claim 1, characterized in that: The hydraulic grab bucket is of model SG70 with a width of 800mm; the main reinforcement of the steel cage is HRB400 grade steel with a diameter of 25mm; the environmentally friendly concrete is C30 concrete with 30% fly ash.

3. The green and efficient underground continuous wall deep foundation pit support structure according to claim 1, characterized in that: The hydraulic grab bucket can be replaced by a trenching machine, the environmentally friendly concrete can be replaced by recycled aggregate concrete, prestressed anchor cables are added to the wall system to improve the overall stability of the support structure, and the concrete guide wall adopts a prefabricated structure.

4. A green and efficient support method for deep foundation pits using diaphragm walls, applied to the green and efficient diaphragm wall support structure for deep foundation pits as described in any one of claims 1-3, characterized in that: The following support methods are included: S1. Surveying and Setting Out: Using a high-precision total station surveying instrument, combined with geographic information system data and construction drawings, the positions of the two symmetrically set concrete guide walls in the guide wall system are accurately determined. At the same time, on the construction site, white lime is used to clearly set out the lines along the survey marks, and a laser setting out device is used for verification and calibration to ensure that the setting out error is controlled within a very small range and to ensure the accuracy of subsequent construction. S2. Guide Wall Construction and Curing: The guide wall is constructed using precast concrete slabs. During production, high-precision molds and automated vibration equipment are used to strictly control the dimensional accuracy within ±2mm. The concrete strength is prepared according to the design strength grade increased by 5%, ensuring its strength is ≥97% of the preset value. After transportation to the site, large cranes are used in conjunction with professional construction personnel for assembly. Assembly is carried out strictly according to the design layout, ensuring uniform and consistent joints between precast slabs. The joints are sealed with high-strength waterproof mortar, with the coating thickness controlled at 5-8mm to ensure a good seal. After assembly, geotextile is promptly covered and watered for moisturizing and curing for no less than 7 days to allow it to reach the design strength. S3. Trenching Operation and Slurry Treatment: A stable hydraulic grab bucket is selected for trenching operations along the guide channel. Before operation, the hydraulic grab bucket is fully tested to ensure that all performance indicators meet the construction requirements. Simultaneously, the slurry circulation system is activated. The slurry circulation system includes a slurry tank, a slurry pump, and slurry delivery pipelines. The slurry tank is divided into a sedimentation tank and a storage tank. Through reasonable zoning design, the sedimentation and storage effects of the slurry are guaranteed. The slurry is transported to the trenching area via the slurry pump and delivery pipelines. The liquid column pressure of the slurry maintains the stability of the trench wall. The density, viscosity, and other performance parameters of the slurry are monitored. Real-time monitoring and recording ensure that the mud performance meets construction requirements; the waste mud treatment device uses advanced centrifugal separation technology to purify the mud, and the purified mud meets the reuse standards, ensuring that the mud can be reused; when encountering hard strata, a trenching machine is promptly used for trenching operations. The milling speed of the trenching machine is controlled at 20-30 rpm, and the speed is adjusted in real time through an automatic control system to ensure milling efficiency and quality; at the same time, mud lubrication is injected synchronously through a dedicated mud injection system to ensure the smooth progress of trenching operations; S4. Trench Section Acceptance and Reinforcing Cage Placement: After trenching is completed, in accordance with standards and specifications, a professional testing tool, including an ultrasonic wall gauge and a steel tape measure, is used to comprehensively inspect key indicators such as verticality, depth, and width of the trench section. The verticality error is controlled within 0.3%, the depth error within ±50mm, and the width error within ±20mm. After acceptance, a professional large crawler crane with special lifting equipment is used to place the reinforcing cage into the trench. The reinforcing cage is manufactured using high-precision molds at the processing site, and automated welding equipment is used to ensure that the geometric dimensions of the reinforcing cage and the spacing of the reinforcing bars meet the design requirements, with the spacing error controlled within ±5mm. During the placement process, multiple reinforcement support points are set on the reinforcing cage, and steel sections or steel pipes are used for reinforcement. S5. Environmentally friendly concrete pouring: Environmentally friendly concrete is poured into the trench using a tremie pipe method. The environmentally friendly concrete is C30 concrete with 30% fly ash or recycled aggregate concrete. Before pouring, the tremie pipe is tested for sealing and strength. During pouring, the tremie pipe is strictly buried in the concrete to a depth of not less than 2m. The pouring speed and tremie pipe lifting speed are dynamically adjusted through a real-time concrete pouring monitoring system to ensure the compactness of the concrete pouring and prevent quality problems such as broken piles and mud inclusions, thus forming a continuous wall. S6. Monitoring system installation: Stress sensors and displacement monitoring points are reasonably arranged around the continuous wall and foundation pit according to the design requirements. The stress sensors adopt high-precision vibrating wire stress gauges, and the displacement monitoring points are monitored by using reflectors in conjunction with high-precision total stations. Establish a real-time monitoring data acquisition and transmission system to transmit monitoring data to the monitoring center in real time. The data will be processed and analyzed by professional data analysis software to monitor the stress and displacement of the support structure in real time. When stress monitoring data exceeds the warning value or the displacement change rate is abnormal, the emergency plan should be activated immediately, and corresponding measures such as increasing support and backfilling should be taken to ensure the safety of the foundation pit. S7. Installation of sonic logging pipes: During the fabrication of the reinforcing cage, sonic logging pipes are installed simultaneously. The sonic logging pipes are made of high-quality metal, and their diameter and wall thickness meet relevant testing standards. The installation position of the sonic logging pipes is accurate, and welding or sleeve connection is used to ensure a firm connection without leakage. The top and bottom of the sonic logging pipes are sealed to prevent foreign matter from entering the pipes, which are used for subsequent ultrasonic testing of the quality of the wall concrete. S8. Dynamic Adjustment of Construction: During the excavation of the foundation pit, the stability of the foundation pit is evaluated in real time based on the stress and displacement data of the support structure fed back by the monitoring system and in conjunction with finite element analysis software. Based on the evaluation results, construction parameters such as excavation speed, excavation sequence, and support setting time are adjusted in a timely manner to reasonably arrange the construction schedule and ensure the safety of the foundation pit and its surrounding environment. At the same time, an information feedback mechanism is established during the construction process, and construction personnel and monitoring personnel maintain close communication to promptly resolve problems that arise during construction.

5. The green and efficient support method for deep foundation pits with diaphragm walls according to claim 4, characterized in that: In step S2, the construction and maintenance of the guide wall, the raw materials for the precast concrete slabs are strictly inspected during factory production. High-quality cement, well-graded aggregates, and high-efficiency water-reducing agents are used to ensure the workability and durability of the concrete. Multiple quality inspection processes are set up on the production line to test the appearance quality, dimensional accuracy, and concrete strength of each precast slab. During transportation, a special transport frame is used to fix the precast slabs to prevent collision damage during transportation. After arriving at the construction site, the precast slabs undergo a second inspection to ensure that they have not been damaged during transportation.

6. The green and efficient support method for deep foundation pits with diaphragm walls according to claim 4, characterized in that: In step S3, the trenching operation and mud treatment, the volume of the mud tank is rationally designed according to the trenching scale and construction progress. An overflow wall and a guide channel are set between the sedimentation tank and the storage tank to ensure that the mud is fully settled in the sedimentation tank before flowing into the storage tank. The mud pump is selected according to the trenching depth, mud conveying distance, and flow rate requirements to ensure that the mud can be delivered to the trenching site in a timely and stable manner. The mud conveying pipeline uses high-strength and corrosion-resistant pipes, and the pipe connection parts use quick couplings with good sealing performance to prevent mud leakage. The mud circulation device is regularly maintained and serviced, the sediment in the mud tank is cleaned, and the operation of the mud pump and mud conveying pipeline is checked to ensure that they operate normally.

7. The green and efficient support method for deep foundation pits with diaphragm walls according to claim 4, characterized in that: In step S4, the acceptance of the trench section and the hoisting of the reinforcing cage, a dedicated quality inspection area is set up at the reinforcing cage processing site to conduct a comprehensive inspection of the completed reinforcing cage, including the specifications, quantity, spacing, and welding quality of the reinforcing bars; non-destructive testing equipment is used to conduct random inspections of the welded joints of the reinforcing cage to ensure that the welding quality meets the requirements; when hoisting the reinforcing cage, the crane model and lifting tools are reasonably selected according to the length and weight of the reinforcing cage, and a detailed hoisting plan is formulated; multiple lifting points are set on the reinforcing cage, and auxiliary equipment such as balance beams are used to ensure that the reinforcing cage remains balanced during hoisting and to avoid twisting and deformation.

8. The green and efficient support method for deep foundation pits with diaphragm walls according to claim 4, characterized in that: In step S6, during the installation of the monitoring system, the emergency plan includes a detailed emergency response process and division of responsibilities, clearly defining the handling measures for different emergency situations. When stress monitoring data exceeds the warning value, the excavation of the foundation pit is immediately stopped, and professional technicians are organized to analyze the monitoring data and determine the stability of the support structure. Based on the analysis results, measures such as increasing the number of supports, changing the support type, or strengthening the support stiffness are taken. When the rate of displacement change is abnormal, the displacement monitoring points are first checked to eliminate monitoring errors. If the displacement is confirmed to be abnormal, surrounding buildings and underground pipelines are promptly investigated to assess the impact on the surrounding environment. Based on the assessment results, measures such as backfilling and unloading are taken to control the further development of displacement and ensure the safety of the foundation pit and the surrounding environment. At the same time, the emergency plan is regularly drilled and revised to ensure its effectiveness and operability.