Double-layer steel sheet pile basement outer wall supporting integrated device and construction method thereof

Abstract

The invention discloses a double-layer steel sheet pile basement exterior wall supporting integrated device which comprises a profile steel continuous wall (3) composed of an H-shaped steel component (1) and an L-shaped steel corner component (2), the H-shaped steel component (1) and the L-shaped steel corner component (2) are each provided with a double-lock-catch piece (4), and monitoring elements (8) are arranged in the double-lock-catch pieces (4); the double-locking fastener (4) comprises a first double-locking fastener (41), a second double-locking fastener (42) and a third double-locking fastener (43), integrated grouting channels are preset in the first double-locking fastener, the second double-locking fastener and the third double-locking fastener, each integrated grouting channel comprises a longitudinal grouting core pipe (5) and a branch grouting hole (6) which are matched with each other, and the lower end of each longitudinal grouting core pipe (5) is connected with a segmented grouting auxiliary mechanism (7). The method has the advantages that the rigidity, the waterproof effect, the construction efficiency and the support and outer wall collaboration of a support structure are improved, and the method has the advantages of external sealing and internal seepage double water stopping, full-life-cycle monitoring and early warning, recoverable profile steel and small environmental influence, and is suitable for deep foundation pit engineering in complex geology.

Description

Technical Field

[0001] This invention belongs to the field of building foundation pit support technology, and particularly relates to an integrated device for double-layer steel sheet pile basement external wall support and its construction method. Background Technology

[0002] In underground engineering construction, the stability of deep foundation pit support and the reliability of waterproofing of basement exterior walls are core factors determining the safety and durability of the project. Currently, commonly used technologies for deep foundation pit support include sheet piles, cast-in-place piles, and diaphragm walls. Among these, sheet piles are widely used in temporary support projects in soft soil areas due to their ease of construction, low cost, and recyclability. However, conventional single-layer sheet piles have two significant drawbacks: first, insufficient structural rigidity, leading to significant deformation in deep foundation pits greater than 8 meters or complex geological environments, failing to meet the requirements for permanent support; second, poor interlock sealing, making leakage prone to occur in areas with abundant groundwater, thus unsuitable as a direct waterproofing structure for basement exterior walls. Furthermore, existing sheet piles lack pre-designed grouting channels, making it easy for subsequent grouting to damage the interlocking structure, compromising the water-stopping effect.

[0003] Existing waterproofing technologies for basement exterior walls primarily employ rolled waterproofing materials, coatings, or structural self-waterproofing. These methods all require work to be carried out within a narrow space of only 0.5 to 1.0 meters between the support structure and the exterior wall after the foundation pit excavation is completed. This not only presents significant operational difficulties and low construction efficiency but also increases the risk of damage to the waterproofing layer due to deformation of the support structure or disturbance of the backfill soil, leading to increased maintenance costs later. Furthermore, traditional support structures and basement exterior walls are independent construction systems, lacking a coordinated stress-bearing mechanism. This makes them prone to cracking due to additional stress caused by uncoordinated deformation. More critically, existing systems only provide short-term construction monitoring functions and lack long-term performance monitoring modules. They cannot detect potential problems such as structural aging and interlocking leaks during the service life phase and lack data-driven predictive capabilities, resulting in delayed risk management throughout the entire life cycle and increasing the probability of engineering safety accidents.

[0004] In recent years, although the industry has attempted to develop technologies that combine support and waterproofing, such as using diaphragm walls as basement exterior walls, this process requires mud slurry wall protection, has complex joint treatment, and is more expensive than steel sheet piles. Furthermore, the waterproofing treatment of wall joints is difficult. There is also a double-layer steel sheet pile support scheme, but the existing double-layer steel sheet piles only form a simple combination through interlocking joints and do not achieve an integrated design of "support-waterproofing-long-term monitoring". They lack interlocking structures with integrated grouting channels, do not systematically deploy multi-parameter sensors, and do not have remote monitoring and machine learning prediction functions. They cannot simultaneously meet the comprehensive requirements of support stiffness, waterproof sealing, and full life cycle early warning. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of insufficient rigidity, poor waterproofing and sealing, high operational difficulty, low construction efficiency, lagging risk management, and poor coordination between support and external wall in existing steel sheet pile structures. It provides an integrated double-layer steel sheet pile basement external wall support device, which has high-strength support capacity, double waterproofing performance, and intelligent monitoring function throughout the entire life cycle. It has minimal environmental impact, fast construction speed, and high economic benefits.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An integrated support device for the outer wall of a double-layer steel sheet pile basement includes a continuous steel wall composed of H-shaped steel members and L-shaped steel corner members, both of which are equipped with double locking fasteners. The H-shaped steel members are connected to the first double-locking fasteners at both ends. Adjacent H-shaped steel members are connected by the first double-locking fasteners on the corresponding sides. The L-shaped steel corner members are connected to the second and third double-locking fasteners at both ends. The L-shaped steel corner members are connected to the first double-locking fasteners of the H-shaped steel members on both sides by the second and third double-locking fasteners, respectively, to form a closed steel continuous wall.

[0007] The first double-locking fastener, the second double-locking fastener, and the third double-locking fastener all have an integrated grouting channel pre-set inside. The integrated grouting channel includes a longitudinal grouting core tube and branch grouting holes that cooperate with each other. The lower end of the longitudinal grouting core tube is connected to a segmented grouting auxiliary mechanism. The segmented grouting auxiliary mechanism includes a sealing gasket, a piston, a spring device, a limiting device, a ball valve, and a grating fiber strain gauge that cooperate with each other. The bottom side of the longitudinal grouting core tube is connected to a sealing gasket, and the middle of the sealing gasket is provided with a grout outlet. A piston is provided on the opposite side of the sealing gasket. The spring device is connected between the piston and the ball valve and is located inside the limiting device. After the piston is subjected to grouting pressure, it pushes the spring device to move horizontally along the axis of the limiting device, so that the ball valve is tightly attached to the inner wall of the double-lock fastener. The grating fiber strain gauge is located between the piston and the spring device. The branch grouting holes include a first grouting hole, a second grouting hole, and a third grouting hole. The first and second grouting holes are equally spaced along the longitudinal axis of the sub-locking fastener. The first and second grouting holes are located on the inner and outer sides of the double-locking fastener, respectively, and are staggered in the height direction. The third grouting hole is equally spaced along the longitudinal axis of the female fastener of the double-locking fastener. The third grouting hole is directly opposite the second grouting hole and the two are connected.

[0008] Monitoring elements are arranged inside both H-beam and L-beam corner components. A longitudinally penetrating mounting groove is opened on both the inner and outer sides of the double-locking fastener. The monitoring elements are evenly distributed in the mounting groove along the longitudinal direction. These include grating fiber optic sensors that monitor strain, temperature, humidity, and pore pressure. By arranging different types of strain gauges in the same range, it is possible to effectively prevent them from being connected together during subsequent monitoring. Separate measurements result in higher detection accuracy and better data extraction. In addition, if leakage is detected by the outer strain gauge but not by the inner strain gauge, waterproof material can be applied to the internal steel sheet pile for seepage prevention.

[0009] The aforementioned sensors are connected to the control terminal via a data bus. The control terminal is associated with a cloud-based monitoring platform and integrates a machine learning prediction module to remotely view monitoring data, provide audible and visual warnings for exceeding standards, and predict long-term deformation trends.

[0010] Furthermore, the H-beam steel member includes two parallel first sheet piles and a first connecting plate perpendicular to the first sheet piles. The first sheet piles have a U-shaped groove along their central axis in the height direction. The two ends of the first connecting plate are CNC machined into an integral I-shaped locking buckle. The I-shaped locking buckle and the U-shaped groove form a locking fit, with a gap of less than 5mm between the locking surfaces, so that the first connecting plate is connected between the two first sheet piles to ensure the structural integrity and shear resistance of the assembled H-beam steel member.

[0011] Furthermore, both ends of the first sheet pile are fixed with submerged arc welding to form first double-locking fasteners. Each first double-locking fastener includes a female fastener and a male fastener. The lengths of the female fastener and the male fastener are the same as the height of the first sheet pile, and the female fasteners and male fasteners on two adjacent first sheet piles are arranged alternately. The male fastener on the corresponding side is inserted into the female fastener to securely connect two adjacent H-beam steel members. This design eliminates the need to deliberately select the member orientation during the construction of the H-beam steel continuous wall, enabling double-locking overlaps in any direction and significantly improving construction efficiency.

[0012] Furthermore, the L-shaped steel corner member includes two perpendicularly connected second sheet piles, two perpendicularly connected third sheet piles, and a second connecting plate. The third sheet pile is located inside the second sheet pile, and the length of the second sheet pile is greater than that of the third sheet pile. Both ends of the second and third sheet piles are flush. The second connecting plate is fixed between the corner of the second sheet pile and the corner of the third sheet pile by submerged arc welding. The L-shaped corner member allows the H-shaped steel members to achieve a 90° turn when continuously overlapping, ultimately forming a closed continuous steel wall. It is suitable for rectangular, square, and other regular foundation pit shapes, avoiding the leakage and insufficient rigidity problems of traditional corners.

[0013] Furthermore, a second double-locking fastener is welded to both ends of the second sheet pile, which includes a female fastener and a male fastener. A third double-locking fastener is welded to both ends of the third sheet pile, which includes a female fastener and a male fastener. The female fasteners 2 and 3 are respectively engaged with the male fastener 1 of the corresponding outermost H-shaped steel member. The male fasteners 2 and 3 are respectively engaged with the female fastener 1 of the corresponding outermost H-shaped steel member. The locking depth is greater than 30mm, which is used to ensure the sealing and structural stability of the splice at the corner, eliminate the risk of leakage at the corner, and achieve full sealing and water stop.

[0014] Furthermore, the longitudinal grouting core tube is respectively installed in the middle cavity of sub-clamp one, sub-clamp two or sub-clamp three and pre-embedded along the height direction of the first steel sheet pile, and the outer wall of the longitudinal grouting core tube is 10mm away from the inner wall of the sub-clamp.

[0015] Furthermore, the spacing between two adjacent first grouting holes, the spacing between two adjacent second grouting holes, and the spacing between two adjacent third grouting holes are all set to 200mm. First grouting holes and second grouting holes are respectively provided on both sides of the first, second, and third sub-clamps, and third grouting holes are provided on the first, second, and third female clamps.

[0016] Furthermore, the spring device includes a spring, a guide post, and a cross seal. The spring is sleeved on the outside of the guide post. One end of the guide post is connected to the piston, and the other end passes through the spring and the cross seal and is connected to the ball valve. The guide post is located on the central axis of the limiting device, and the cross seal is connected to the limiting device. The limiting device has a flared structure, and its small end is fixed to the outer wall of the longitudinal grouting core tube. The segmented grouting auxiliary mechanism also includes a camera. The camera is located above the sealing gasket and is set directly in the grouting direction of the sealing gasket to facilitate real-time observation of the grouting situation.

[0017] The monitoring elements used in this invention include grating fiber optic sensors for monitoring strain, temperature, humidity, and pore pressure; the displacement sensor is connected to a control terminal with a wireless transmission module via a data bus for real-time monitoring of the overall deformation state of the steel continuous wall; grating fiber optic sensors are attached inside the double-lock fasteners to monitor strain, temperature, humidity, and pore pressure, and the grating fiber optic sensors can achieve simultaneous monitoring of "overall deformation, lock leakage, and grouting effect".

[0018] The fiber optic grating sensor used in this invention has a stress monitoring accuracy of ±5MPa, a humidity monitoring accuracy of ±2% RH, a temperature monitoring accuracy of ±0.1℃, and a pore pressure monitoring accuracy of ±0.5kPa. It is connected to a control terminal via a data bus. The control terminal is linked to a cloud-based monitoring platform and integrates machine learning prediction modules, such as LSTM models, enabling remote viewing of monitoring data, audible and visual warnings of exceeding standards, and prediction of long-term deformation trends. Warning thresholds are: displacement exceeding 30mm, humidity exceeding 85%, and strain exceeding the design value by 100%.

[0019] To further achieve the objectives of this invention, a construction method for an integrated double-layer steel sheet pile basement exterior wall support device is also provided, the specific steps of which are as follows: S1, Site leveling: Clean the site at the selected foundation pit location, remove surface debris and obstacles, compact the site using compaction equipment, and verify the site bearing capacity through plate load tests to avoid construction equipment settlement causing component installation deviations and ensure that the site bearing capacity meets the operation requirements of construction equipment.

[0020] S2, Positioning and Trenching: Based on the design dimensions of the foundation pit, use a total station or GNSS positioning equipment to lay out the positioning lines for the retaining piles, marking that the axial position deviation of each H-beam steel member is less than 5mm. Then, use a small excavator to excavate the retaining pile trench along the positioning lines. The depth and width of the trench match the dimensions of the sheet piles and the construction operation space.

[0021] S3, Inspection of Locking Pre-hole and Grouting Channel: Based on the preset positions and dimensions of the first to third locking components, a geological drilling rig is used to drill pre-holes at the locking positions; the depth of the pre-hole is consistent with the designed insertion depth of the sheet pile, and the hole diameter is 5-10mm larger than the diameter of the double locking components, leaving space for water-stopping grouting; after drilling, a high-pressure water gun is used to clean the soil inside the hole to ensure that the hole wall is flat and without collapse; at the same time, the integrated grouting channel of the precast sheet pile is inspected, and the longitudinal main pipe is purged with compressed air to ensure that the main pipe is not blocked and the branch hole check valve is unobstructed. The branch hole check valve is pressed to ensure that the valve core is flexible, and the bottom of the main pipe is temporarily sealed with a rubber sealing cap.

[0022] S4, Component Installation: S41, Test element layout: Apply epoxy resin adhesive evenly to the inner wall of the double locking fastener and attach the grating fiber optic sensor that monitors strain, temperature, humidity and pore pressure; the sensor lead wire is laid along the reserved groove on the inner side of the locking fastener, the lead wire joint is wrapped with 3 layers of water-stop tape for sealing, and the end is temporarily fixed to the top of the steel sheet pile. S42, First sheet pile driving: According to the geological conditions, a static pressure pile driver or vibratory hammer is used to drive the first sheet pile with pre-installed sensors and grouting channels vertically to the designed insertion depth along the lock hole position. During the driving process, the verticality is calibrated in real time by a laser plumb line to avoid excessive deviation. S43, Connecting plate installation: After the first steel plate is driven, align the I-shaped locking buckles at both ends of the first connecting plate with the U-shaped slots of the corresponding first steel sheet piles, and use a hydraulic press to press and fix them to form a single H-section steel component unit. S44, segmented splicing: following the process of "sensor deployment, sheet pile driving, and connecting plate installation", adjacent first sheet piles and first connecting plates are driven and assembled in sequence, and continuous splicing is achieved through the cross matching of the first locking fasteners; S45, Corner component installation: When construction reaches the corner of the foundation pit, a grating fiber optic sensor is pasted inside the double-locking fastener of the L-shaped steel corner component. Then, it is matched with the double-locking fastener of the adjacent first steel sheet pile and driven to the design depth using a vibratory hammer to complete the corner connection. S46, Continuous wall closure: Repeat the above steps until all components are assembled to form a closed steel continuous wall. At the same time, connect the sensor leads to the field data acquisition box to conduct preliminary sensor signal testing.

[0023] S5, multiple-layer water-stop grouting: S51, First external sealing grouting: Fill the external gap at the double-lock fastener lead hole with cement-based grouting material with a water-cement ratio of 0.65. Use low pressure and slow injection. Stop grouting when the grout overflows from the adjacent branch hole and continue grouting for the next sheet pile. S52, Maintenance and Monitoring: After external grouting, cover with geotextile for 48 hours to maintain moisture and monitor the humidity of the locking parts through a grating fiber optic sensor. S53, Second internal seepage grouting: After the curing is qualified, cement-based grouting material with a water-cement ratio of 0.5 is injected into the grouting channel. Medium pressure grouting is used. The grout penetrates into the tiny gaps inside the double-lock fastener through the first grouting hole and forms a rigid waterstop after solidification. S54, Third reinforcement: Within one week after the foundation pit is excavated to the bottom elevation, ultrafine cement grout is injected into the grouting channel. Low-pressure grouting is used, and the stress state of the grouting body is monitored by a grating fiber optic sensor to ensure no cracking, make up for the blind spots of the first two groutings, and achieve double water stop.

[0024] S6, Excavation and Installation of Internal Supports: After the grouting material has cured and the sensors have been properly adjusted, the foundation pit is excavated in layers. The excavation sequence strictly follows the principle of "support first, then excavate; layered excavation; and completion within a time limit." The excavation depth of each layer does not exceed 2m. Simultaneously, the deformation and locking status of the steel continuous wall are monitored in real time through the control terminal. After each layer of excavation is completed, the steel support internal support frame is installed in a timely manner. The two ends of the steel support are welded and fixed to the steel continuous wall through embedded parts, and jacks are used to apply pre-loaded axial force to the steel support. The above steps are repeated until the excavation reaches the designed foundation pit bottom elevation. S7, Long-term monitoring system debugging: S71, Sensor Calibration: The grating fiber optic sensor is calibrated on-site using a standard strain source and humidity source to ensure that the monitoring accuracy meets the standards; S72, Wireless Transmission Test: Simulate different working conditions to verify the stability of data transmission between the control terminal and the cloud platform; S73, Warning Threshold Setting: Set three-level warning thresholds according to engineering design values, and link the on-site audible and visual alarms; S74, Machine Learning Model Training: Collect monitoring data for 6 months during the construction period, import it into the LSTM prediction model for training, and realize the prediction of deformation trends in the next 1-3 years; in the subsequent use stage, the model data is updated regularly to realize the closed-loop management of "monitoring-early warning-prediction-maintenance" throughout the entire life cycle.

[0025] Furthermore, in step S5, the sealing gasket of the longitudinal grouting core tube prevents grout from leaking inward during grouting, the spring device provides elastic restoring force, the limiting device restricts the movement direction of the ball valve during grouting to keep it horizontal, the ball valve ensures that the force applied during grouting is evenly distributed on the pipe wall, and the grating fiber strain gauge is laid along the outside of the pipe to measure the grouting pressure in real time and achieve active control; before construction, the spring device tightens to put the ball valve in a lowered and closed state; during construction, the grout is discharged along the grouting port, and the grouting pressure pushes the ball valve toward the pipe wall through the piston and spring device, the limiting device keeps the ball valve moving horizontally, and the ball valve ensures that the force on the pipe wall is even to ensure stable grout flow, while the grating fiber strain gauge monitors and controls the pressure in real time; after construction is completed, the pressure is released, the spring device contracts and rebounds to drive the ball valve to close, making it easy to lift the grouting core tube to the next grouting point, thus achieving efficient, safe and precise control of the grouting process.

[0026] The full life cycle intelligent monitoring module used in this invention can monitor the grouting situation inside the pipe in real time. The full life cycle intelligent monitoring module specifically includes: (1) Multiple types of sensor configuration: Strain sensors, humidity sensors, temperature sensors and pore pressure sensors are pasted on the inner walls of the first to third double-locking fasteners on the inner side of the H-shaped steel components and L-shaped steel corner components to capture changes in locking stress, leakage, ambient temperature and groundwater pressure, respectively. (2) Sensor protection and deployment: The surface of the steel sheet pile is ground and rusted, and then cleaned with anhydrous ethanol. The sensor is then pasted with high-strength epoxy resin. The outside of the sensor is covered with a protective shell, and the inside of the shell is filled with waterproof sealant to prevent groundwater erosion. The lead wire is laid along the reserved channel on the inside of the steel sheet pile. The distance between the sensor and the grouting channel is greater than 10mm to prevent the grouting pressure from squeezing the sensor or lead wire. (3) Data transmission and early warning: A data acquisition box is set up on site to transmit data to the site gateway via a wireless module, and then upload it to the cloud monitoring platform via 5G; a three-level early warning threshold is set, and the on-site sound and light alarm is triggered when the threshold is exceeded; (4) Machine learning prediction: Collect monitoring data during the construction and use periods, and train an LSTM long short-term memory network model; the model can predict the structural deformation trend in the next 1 to 3 years, and automatically generate preventive maintenance suggestions when the predicted value is close to the secondary warning threshold.

[0027] Compared with the prior art, the advantages of the technical solution of the present invention are as follows: (1) Significantly improved stiffness and strength: Through the precise assembly of the U-shaped slot and the I-shaped lock, and the cross-lapping of the double lock fasteners, the overall stiffness of the H-shaped steel component is better than that of conventional Larssen steel sheet piles, and the shear bearing capacity is significantly improved, which can meet the permanent support requirements of complex geology; (2) High reliability of double-layer water stop: The integrated grouting channel realizes multiple and multi-layer grouting of "external sealing-internal seepage-replenishment", and the superimposed grating fiber humidity sensor monitors in real time, which significantly reduces the leakage rate of the locking and eliminates the need for an additional waterproof layer, thus reducing waterproofing costs. (3) Intelligent management and control throughout the entire life cycle: multi-parameter sensors, wireless remote transmission, and machine learning prediction enable full-process management and control from risk warning during construction to long-term monitoring during use and recycling assessment during decommissioning. It can detect hidden dangers 24 hours in advance and extend the structural safety guarantee period. (4) Excellent integration and synergy: It realizes the integrated design of "support-waterproofing-monitoring-exterior wall", avoids the synergy problem of traditional independent construction, reduces the risk of structural cracking caused by additional stress, can shorten the construction period and reduce the overall cost; (5) Outstanding green economy: For steel components that are not used as underground continuous walls for long-term use but only for short-term support, they can be pulled out by hydraulic pile extractor after the main structure is completed, and reused 3 to 5 times after sandblasting and rust removal, saving steel; low vibration equipment is used in construction, which meets the requirements of green construction. (6) Strong adaptability to working conditions: The H-shaped steel section can be adjusted as needed, and the L-shaped steel corner component meets the requirements of various foundation pit shapes such as rectangle and square. It is suitable for different geological conditions such as soft soil, sand layer, and clay layer, and is compatible with various underground engineering scenarios such as residential basement, underground pipe gallery, and industrial plant. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the first steel sheet pile structure of the present invention; Figure 2 This is a schematic diagram of the first connecting plate structure of the present invention; Figure 3 This is a schematic diagram of the H-beam steel component assembly structure of the present invention; Figure 4 This is a schematic diagram of the splicing of two adjacent H-shaped steel components in this invention; Figure 5 This is a structural schematic diagram of the L-shaped steel corner member of the present invention; Figure 6 This is a schematic diagram of the splicing of the L-shaped steel corner member and the H-shaped steel member in this invention; Figure 7 This is an overall layout diagram of the spliced ​​steel continuous wall in this invention; Figure 8 This is a schematic diagram showing the corresponding height distribution of the first, second, and third grouting holes in this invention; Figure 9 This is a schematic diagram showing the corresponding positions of the branch grouting holes and monitoring elements in a cross-section of the present invention. Figure 10 This is a schematic diagram of the segmented grouting auxiliary mechanism of the present invention; Figure 11 This is a schematic diagram of the grout distribution during external sealing and internal seepage grouting in this invention; Figure 12 This is a schematic diagram of the long-term monitoring device for seepage prevention performance in this invention; Figure 13 This is a flowchart of the long-term monitoring device for seepage prevention performance in this invention; Figure 14 This is a schematic diagram of the construction process for the seepage prevention performance of this invention. Detailed Implementation Example

[0029] To make the present invention clearer, the following description, in conjunction with the accompanying drawings, further illustrates an integrated double-layer steel sheet pile basement external wall support device and its construction method. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] In this invention, taking a rectangular steel continuous wall as an example, the side of each double-locking fastener 4 closest to the inside of the rectangular structure is defined as the inner side, and the side closest to the outside of the rectangular structure is defined as the outer side, such as... Figure 7 As shown.

[0031] See Figure 7 An integrated support device for the outer wall of a double-layer steel sheet pile basement includes a set of H-shaped steel components 1 spliced ​​along a straight line and four L-shaped steel corner components 2, which are spliced ​​together to form a closed steel continuous wall 3.

[0032] (a) Steel continuous wall See Figures 1-4 H-beam component 1 is a prefabricated H-beam, specifically as follows: The H-beam steel member 1 includes two parallel first sheet piles 11 and a first connecting plate 12 perpendicular to the first sheet piles 11. The first sheet piles 11 are provided with U-shaped slots 111 along the central axis of the height direction. The two ends of the first connecting plate 12 are CNC machined into I-shaped locking buckles 121. The I-shaped locking buckles 121 and the U-shaped slots 111 form a locking fit. The two are pressed and fixed by a hydraulic press. The gap between the locking surfaces is less than 5mm, so that the first connecting plate 12 is connected between the two first sheet piles 11.

[0033] See Figure 5 and Figure 6The L-shaped steel corner member 2 includes two vertically connected second steel sheet piles 21, two vertically connected third steel sheet piles 22, and a second connecting plate 23. The third steel sheet pile 22 is located inside the second steel sheet pile 21, and the length of the second steel sheet pile 21 is greater than that of the third steel sheet pile 22. Both ends of the second steel sheet pile 21 and the third steel sheet pile 22 are flush. The second connecting plate 23 is fixed between the corner of the second steel sheet pile 21 and the corner of the third steel sheet pile 22 by submerged arc welding.

[0034] See Figures 1-7 The two ends of the H-shaped steel member 1 are connected to the first double locking fastener 41. Two adjacent H-shaped steel members 1 are connected by the first double locking fastener 41 on the corresponding side. The two ends of the L-shaped steel corner member 2 are connected to the second double locking fastener 42 and the third double locking fastener 43. The L-shaped steel corner member 2 is connected to the first locking fastener 41 of the H-shaped steel members 1 on both sides by the second and third double locking fasteners respectively, forming a closed steel continuous wall 3.

[0035] (ii) Integrated grouting channel See Figures 8-11 The first double-lock fastener 41, the second double-lock fastener 42 and the third double-lock fastener 43 are all pre-set with integrated grouting channels. The integrated grouting channels include longitudinal grouting core tubes 5 and branch grouting holes 6 that cooperate with each other. The lower end of the longitudinal grouting core tube 5 is connected to a segmented grouting auxiliary mechanism 7.

[0036] See Figure 1 , Figure 3 , Figure 5 The first double-locking fastener 41 includes a female fastener 411 and a female fastener 412; the second double-locking fastener 42 includes a female fastener 421 and a female fastener 422; and the third double-locking fastener 43 includes a female fastener 431 and a female fastener 432. The longitudinal grouting core tube 5 is respectively installed in the middle cavity of the female fastener 412, the female fastener 422, or the female fastener 432 and is pre-embedded along the height direction of the first steel sheet pile 11. The outer wall of the longitudinal grouting core tube 5 is 10mm away from the inner wall of the female fastener.

[0037] See Figure 8 and Figure 9 The branch grouting hole 6 includes a first grouting hole 61, a second grouting hole 62, and a third grouting hole 63. The first grouting hole 61 and the second grouting hole 62 are equally spaced along the longitudinal axis of the sub-lock fastener 4. The first grouting hole 61 and the second grouting hole 62 are respectively located on the inner and outer sides of the double-lock fastener 4, and the first grouting hole 61 and the second grouting hole 62 are staggered in the height direction. The third grouting hole 63 is equally spaced along the longitudinal axis of the female fastener 4. The third grouting hole 63 is directly opposite the second grouting hole 62 and the two are connected.

[0038] See Figure 9 and Figure 10The segmented grouting auxiliary mechanism 7 includes a sealing gasket 71, a piston 72, a spring device 73, a limiting device 74, and a ball valve 75 that cooperate with each other. The bottom side of the longitudinal grouting core tube 5 is connected to the sealing gasket 71. The middle part of the sealing gasket 71 is provided with a grout outlet hole 71a. The opposite side of the sealing gasket 71 is provided with the piston 72. The spring device 73 is connected between the piston 72 and the ball valve 75, and the spring device 73 is located inside the limiting device 74. After the piston 72 is subjected to grouting pressure, it pushes the spring device 73 to move horizontally along the axis of the limiting device 74, so that the ball valve 75 is tightly attached to the inner wall of the sub-lock of the double-lock fastener 4. Specifically, the spring device 73 includes a spring 731, a guide post 732, and a cross seal 733. The spring 731 is sleeved on the outside of the guide post 732. One end of the guide post 732 is connected to the piston 72, and the other end passes through the spring 731 and the cross seal 733 and is connected to the ball valve 75. The guide post 732 is located on the central axis of the limiting device 74, and the cross seal 733 is connected to the limiting device 74. The limiting device 74 has a flared structure, and its small end is fixed to the outer wall of the longitudinal grouting core tube 5.

[0039] (III) Configuration of Intelligent Detection Module See Figure 8 , Figure 9 , Figure 11 Monitoring elements 8 are arranged in both the H-shaped steel component 1 and the L-shaped steel corner component 2. A longitudinal through mounting groove 81 is opened on the inner and outer sides of the double-lock fastener 4. The monitoring element 8 is pasted in the mounting groove 81 along the longitudinal direction. The monitoring element 8 includes a grating fiber optic sensor for monitoring strain, temperature, humidity and pore pressure.

[0040] In addition, see Figure 10 The segmented grouting auxiliary mechanism 7 is also equipped with a grating fiber strain gauge 76 and a camera 77. The grating fiber strain gauge 76 is located between the piston 72 and the spring device 73. The camera 77 is located above the sealing gasket 71 and is set directly in the grout discharge direction of the sealing gasket 71, so that the strain gauge can measure the grouting pressure in real time and the camera can observe the grout discharge in real time, and realize the active control of the grouting process.

[0041] See Figure 12 and Figure 13 The aforementioned sensors are connected to the data acquisition box via leads, and the data is transmitted to the cloud platform via the module, where an LSTM prediction model is integrated. Simultaneously, the cloud platform supports access via a mobile app, resulting in a short warning response time.

[0042] See Figure 14 The construction method using the aforementioned integrated double-layer steel sheet pile basement external wall support device is shown in the figure below, with the specific steps as follows: S1, Site leveling: The site was compacted using a vibratory roller, and the plate load test showed that the bearing capacity was greater than 150 kPa; S2, Positioning and Grooving: Total station positioning, axis deviation less than 5mm; groove depth and width meet dimensional requirements; S3, Inspection of locking pilot hole and grouting channel: Geological drilling rig pilot hole, high-pressure water gun to remove slag; compressed air to purge grouting channel to confirm no blockage; S4, Component installation: The static pressure pile driver drives the first steel sheet pile, and the laser plumb bob is used to calibrate the verticality; the hydraulic press installer installs the first connecting plate, and the gap between the clamping surfaces is less than 3mm; the sections are spliced ​​together to form a straight continuous wall, and the sensor leads are connected to the data acquisition box. S5, multiple layers of water-stop grouting: ① External sealing grouting: cement-based material with a water-cement ratio of 0.65, low-pressure grouting, curing for 48 hours, humidity sensor shows less than 72%; ② Internal seepage grouting: cement-based material with a water-cement ratio of 0.5, medium-pressure grouting; ③ Reinforcement grouting: ultra-fine cement grout, low-pressure grouting. S6, Excavation of foundation pit: Excavate in layers to a depth of 2m. After excavating to the bottom elevation, check the maximum horizontal displacement of the continuous wall and the moisture content of the interlocking to ensure no leakage. S7, long-term monitoring and debugging: sensor calibration, low-latency wireless transmission; input of early warning thresholds, training of LSTM models; regular updates of model data during use.

[0043] In this embodiment, the cross-sectional dimensions of the H-beam steel components can be flexibly adjusted according to the engineering strength requirements. Both the H-beam steel components and the L-beam steel corner components are prefabricated in the factory in batches and processed by CNC cutting and welding robots to ensure the processing accuracy of the U-shaped slots, I-shaped locks, grouting channels and lock parts, so as to meet the requirements of rapid on-site assembly.

[0044] The double-locking steel sheet pile continuous steel wall of this invention, through "external sealing-internal seepage" dual-stage grouting and full life-cycle intelligent monitoring, can detect potential leakage or structural deformation of the locking mechanism 24 hours in advance. Combined with grouting maintenance, the service life of the system can be extended to more than 15 years. Construction equipment can be flexibly selected according to geological conditions, with minimal disturbance to the surrounding environment. The steel has a high recycling rate, which greatly reduces resource consumption and engineering costs. It has significant technical, economic and environmental benefits and can be widely applied to various underground engineering projects.

[0045] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. An integrated support device for double-layer steel sheet pile basement exterior walls, characterized in that: The steel continuous wall (3) consists of H-shaped steel members (1) and L-shaped steel corner members (2), and both the H-shaped steel members (1) and the L-shaped steel corner members (2) are equipped with double locking fasteners (4). Among them, the two ends of the H-shaped steel member (1) are connected to the first double locking fastener (41), and the two adjacent H-shaped steel members (1) are connected by the first double locking fastener (41) on the corresponding side. The two ends of the L-shaped steel corner member (2) are connected to the second double locking fastener (42) and the third double locking fastener (43), and the L-shaped steel corner member (2) is connected to the first double locking fastener (41) of the two H-shaped steel members (1) on both sides by the second and third double locking fasteners respectively, forming a closed steel continuous wall (3). The first double-lock fastener (41), the second double-lock fastener (42) and the third double-lock fastener (43) are all pre-set with integrated grouting channels. The integrated grouting channels include longitudinal grouting core tubes (5) and branch grouting holes (6) that cooperate with each other. The lower end of the longitudinal grouting core tube (5) is connected to a segmented grouting auxiliary mechanism (7). The segmented grouting auxiliary mechanism (7) includes a sealing gasket (71), a piston (72), a spring device (73), a limiting device (74), a ball valve (75), and a grating fiber strain gauge (76) that cooperate with each other. The bottom side of the longitudinal grouting core tube (5) is connected to the sealing gasket (71). The middle part of the sealing gasket (71) is provided with a grout outlet hole (71a). The opposite side of the sealing gasket (71) is provided with a piston (72). The spring device (73) is connected between the piston (72) and the ball valve (75). The spring device (73) is located inside the limiting device (74). After the piston (72) is subjected to grouting pressure, it pushes the spring device (73) to move horizontally along the axis of the limiting device (74), so that the ball valve (75) is tightly attached to the inner wall of the double-lock fastener (4). The grating fiber strain gauge (76) is located between the piston (72) and the spring device (73). The branch grouting holes (6) include a first grouting hole (61), a second grouting hole (62) and a third grouting hole (63). The first and second grouting holes are equally spaced along the longitudinal axis of the sub-lock fastener (4). The first grouting hole (61) and the second grouting hole (62) are respectively located on the inner and outer sides of the double-lock fastener (4), and the first grouting hole (61) and the second grouting hole (62) are staggered in the height direction. The third grouting hole (63) is equally spaced along the longitudinal axis of the female fastener (4). The third grouting hole (63) is directly opposite the second grouting hole (62) and the two are connected. Monitoring elements (8) are arranged in both the H-shaped steel member (1) and the L-shaped steel corner member (2). A longitudinal through-groove mounting groove (81) is opened on both the inner and outer sides of the double-lock fastener (4). The monitoring elements (8) are evenly distributed in the mounting groove (81) along the longitudinal direction. They include grating fiber optic sensors for monitoring strain, temperature, humidity and pore pressure. The sensors are connected to the data acquisition box through leads and transmitted to the cloud platform through the module to integrate the LSTM prediction model.

2. The integrated double-layer steel sheet pile basement external wall support device according to claim 1, characterized in that: The H-shaped steel member (1) includes two parallel first sheet piles (11) and a first connecting plate (12) perpendicular to the first sheet piles (11). The first sheet piles (11) are provided with a U-shaped groove (111) along the central axis of the height direction. The two ends of the first connecting plate (12) are CNC machined into an integral I-shaped locking buckle (121). The I-shaped locking buckle (121) and the U-shaped groove (111) form a snap-fit ​​fit. The gap between the snap-fit ​​surfaces is less than 5mm, so that the first connecting plate (12) is connected between the two first sheet piles (11).

3. The integrated double-layer steel sheet pile basement external wall support device according to claim 2, characterized in that: Both ends of the first sheet pile (11) are fixed with submerged arc welding. Each first double locking fastener (41) includes a female fastener (411) and a male fastener (412). The length of the female fastener (411) and the male fastener (412) is the same as the height of the first sheet pile (11). The female fastener (411) and the male fastener (412) on two adjacent first sheet piles (11) are arranged alternately. The male fastener (412) on the corresponding side is inserted into the female fastener (411) so that the two adjacent H-shaped steel members (1) are tightly connected.

4. The integrated double-layer steel sheet pile basement external wall support device according to claim 3, characterized in that: The L-shaped steel corner member (2) includes a second steel sheet pile (21) with two sides perpendicularly connected, a third steel sheet pile (22) with two sides perpendicularly connected, and a second connecting plate (23). The third steel sheet pile (22) is located inside the second steel sheet pile (21), and the length of the second steel sheet pile (21) is greater than that of the third steel sheet pile (22). Both ends of the two are flush. The second connecting plate (23) is fixed between the corner of the second steel sheet pile (21) and the corner of the third steel sheet pile (22) by submerged arc welding.

5. The integrated double-layer steel sheet pile basement external wall support device according to claim 4, characterized in that: The second sheet pile (21) is welded with a second double-locking fastener (42) at both ends, which includes a female fastener (421) and a male fastener (422). The third sheet pile (22) is welded with a third double-locking fastener (43) at both ends, which includes a female fastener (431) and a male fastener (432). The female fastener (421) and the female fastener (431) are respectively engaged with the male fastener (412) of the corresponding outermost H-shaped steel member. The male fastener (422) and the male fastener (432) are respectively engaged with the female fastener (411) of the corresponding outermost H-shaped steel member. The locking engagement depth is greater than 30mm.

6. The integrated double-layer steel sheet pile basement external wall support device according to claim 5, characterized in that: The longitudinal grouting core tube (5) is respectively installed in the middle cavity of sub-clamp one (412), sub-clamp two (422) or sub-clamp three (432) and pre-embedded along the height direction of the first steel sheet pile (11). The outer wall of the longitudinal grouting core tube (5) is 10mm away from the inner wall of the sub-clamp.

7. The integrated double-layer steel sheet pile basement external wall support device according to claim 5, characterized in that: The spacing between two adjacent first grouting holes (61), the spacing between two adjacent second grouting holes (62), and the spacing between two adjacent third grouting holes (63) are all set to 200mm. The first grouting hole (61) and the second grouting hole (62) are respectively set on both sides of the first (412), the second (422) and the third (432) of the female buckle, and the third grouting hole (63) is set on the female buckle, the second (421) and the third (431).

8. The integrated double-layer steel sheet pile basement external wall support device according to any one of claims 1 to 7, characterized in that: The spring device (73) includes a spring (731), a guide post (732) and a cross seal (733). The spring (731) is sleeved on the outside of the guide post (732). One end of the guide post (732) is connected to the piston (72), and the other end passes through the spring (731) and the cross seal (733) and is connected to the ball valve (75). The guide post (732) is located on the central axis of the limiting device (74), and the cross seal (733) is connected to the limiting device (74). The limiting device (74) has a flared structure and its small end is fixed on the outer wall of the longitudinal grouting core tube (5). The segmented grouting auxiliary mechanism (7) also includes a camera (77). The camera (77) is located above the sealing gasket (71) and is set directly in the grouting direction of the sealing gasket (71).

9. A construction method for an integrated double-layer steel sheet pile basement external wall support device as described in any one of claims 1 to 7, characterized in that, include: S1, Site leveling: Clean the site at the selected excavation pit location, remove surface debris and obstacles, compact the site, and ensure that the site's bearing capacity meets the requirements for construction equipment operation; S2, Positioning and trenching: Use a total station or GNSS positioning equipment to set up the positioning line of the retaining piles, and excavate the trench of the retaining piles along the positioning line. The depth and width of the trench are matched with the size of the steel sheet piles and the construction operation space. S3, Inspection of locking lead hole and grouting channel: According to the preset position and size of the first to third locking components, make lead holes at the locking positioning point; the depth of the lead hole is consistent with the design insertion depth of the steel sheet pile, and the hole diameter is 5~10mm larger than the diameter of the double locking components. After the lead hole is made, clean the soil in the hole, and at the same time check the integrated grouting channel of the precast steel sheet pile to ensure that the main pipe is not blocked and the one-way valve of the branch hole is unobstructed. Press the one-way valve of the branch hole and temporarily seal the bottom of the main pipe with a rubber sealing cap. S4, Component Installation: S41, test element layout: apply epoxy resin glue evenly to the inner wall of the double-lock fastener (4) and paste the grating fiber optic sensor; lay the sensor lead wire along the reserved groove on the inner side of the lock, wrap the lead wire joint with 3 layers of water-stop tape for sealing, and temporarily fix the end to the top of the steel sheet pile. S42, First sheet pile (11) driving: Using a static pressure pile driver or vibratory hammer, the first sheet pile (11) with pre-installed sensor and grouting channel is driven vertically along the lock hole to the designed insertion depth. During the driving process, the verticality is calibrated in real time by a laser plumb bob. S43, Connecting plate installation: After the first steel plate (11) is driven, align the I-shaped buckles (121) at both ends of the first connecting plate (12) with the concave slots (111) of the corresponding first steel sheet pile (11), and use a hydraulic press to press and fix them to form a single H-section steel component unit. S44, segmental splicing: following the process of "sensor deployment, sheet pile driving, and connecting plate installation", adjacent first sheet piles (11) and first connecting plates (12) are driven and assembled in sequence, and continuous splicing is achieved through the cross matching of the first locking fasteners (41); S45, installation of corner components: When construction reaches the corner of the foundation pit, a sensor is placed in the double-locking fastener of the L-shaped steel corner component (2), and then matched with the double-locking fastener of the adjacent first steel sheet pile (1), and driven to the design depth to complete the corner connection; S46, Continuous wall closure: Repeat the above steps until all components are spliced ​​together to form a closed steel continuous wall (3). S5, multiple-layer water-stop grouting: S51, First external sealing grouting: Fill the external gap at the lead hole of the double lock fastener (4) with cement-based grouting material with a water-cement ratio of 0.65, and use low pressure and slow injection. Stop grouting when the grout overflows from the adjacent branch hole. S52, Maintenance and Monitoring: After external grouting, maintain the humidity of the locking parts for 48 hours using a grating fiber optic sensor. S53, Second internal seepage grouting: Inject cement-based grouting material with a water-cement ratio of 0.5 into the grouting channel, and use medium pressure grouting. The grout penetrates through the first grouting hole (61) into the tiny gap inside the double-lock fastener (4), and forms a rigid waterstop after solidification. S54, Third reinforcement: Within one week after the foundation pit is excavated to the bottom elevation, ultrafine cement grout is injected into the grouting channel. Low-pressure grouting is used, and the stress state of the grout body is monitored by sensors to ensure that there is no cracking. S6, Excavation and installation of internal supports: Excavate the foundation pit in layers, with each layer not exceeding 2m in depth. Simultaneously monitor the deformation and locking status of the steel continuous wall in real time through the control terminal. After each layer of excavation is completed, install the steel support internal support frame in a timely manner until the excavation reaches the designed foundation pit bottom elevation. S7, Long-term monitoring system debugging: S71, Sensor Calibration: The grating fiber optic sensor is calibrated on-site using a standard strain source and humidity source to ensure that the monitoring accuracy meets the standards; S72, Wireless Transmission Test: Verify the stability of data transmission between the control terminal and the cloud platform; S73, Warning Threshold Setting: Set three-level warning thresholds according to engineering design values, and link the on-site audible and visual alarms; S74, Machine Learning Model Training: Collect monitoring data during the construction period, import it into the LSTM prediction model for training, and realize the prediction of deformation trends in the next 1-3 years; in the subsequent use stage, the model data is updated regularly to realize full life cycle monitoring and management.

10. The construction method of the integrated double-layer steel sheet pile basement external wall support device according to claim 9, characterized in that: In step S5, before construction, the spring device (73) tightens to put the ball valve (75) in a closed state. During construction, the grout is discharged along the grouting port. The grouting pressure pushes the ball valve (75) towards the pipe wall through the piston (72) and the spring device (73). The limiting device (74) keeps the ball valve (75) moving horizontally. The ball valve (75) makes the pipe wall bear force evenly to ensure stable flow of grout. At the same time, the grating fiber strain gauge (76) monitors and adjusts the pressure in real time. After construction is completed, the pressure is released, the spring device (73) contracts and rebounds to drive the ball valve (75) to close, so that the longitudinal grouting core tube (5) can be lifted to the next grouting point.

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