An intelligent support system and construction method for foundation pits close to existing structures

Abstract

The present invention discloses an intelligent support system and construction method for a foundation pit adjacent to an existing structure, belonging to the technical field of foundation pit construction. The system comprises a retaining unit outside the foundation pit, wherein a support unit is arranged inside the retaining unit, and the retaining unit comprises a first block and a second block; the area of the second block is smaller than the area of the side where the receiving groove is located; the support unit comprises a plurality of horizontal support systems, and the horizontal support system comprises a plurality of servo steel support beams between the first block and the second block at the corresponding position of the second block. During foundation pit excavation, the servo steel support beam pushes the second block to control the deformation of the soil in the area of the existing structure, thereby implementing differentiated resistance compensation for the regional deformation risk of the existing structure; after the foundation pit excavation is completed, by grouting between the first block and the second block to connect the two into a whole, stronger support is provided in the high-risk area to prevent the occurrence of excessive deformation in the high-risk area, and no material waste will occur in the low-risk area.

Description

Technical Field

[0001] The present invention belongs to the technical field of foundation pit construction, and in particular relates to an intelligent support system for a foundation pit close to an existing structure and a construction method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the increasing density of urban underground space development, the number of foundation pit projects near existing buildings is increasing. Traditional foundation pit support technologies (such as pile support, underground continuous walls, and steel support systems) have exposed significant technical limitations in complex environments:

[0004] First, traditional rigid support systems cannot dynamically adjust to soil stress changes, resulting in a lag in deformation control. Monitoring relies primarily on manual, periodic data collection, making it difficult to capture sudden displacement changes in a timely manner, causing deformation of existing structures to exceed safety limits.

[0005] Secondly, the traditional support structure has a fixed stiffness and cannot implement differentiated resistance compensation for the deformation risks in different areas of the foundation pit. For example, when one side of the foundation pit is adjacent to a sensitive building, this side requires higher-intensity deformation suppression, but conventional technology still uses uniformly distributed support parameters, resulting in excessive deformation in high-risk areas or material waste in low-risk areas. Summary of the Invention

[0006] To address the above issues, the present invention provides an intelligent support system and construction method for foundation pits near existing structures. By connecting a serial fixed inclinometer, a servo steel support beam, and a monitoring platform, the system monitors soil deformation around the foundation pit in real time and makes precise dynamic adjustments based on the monitoring results. Separate first and second blocks are arranged, and a servo steel support beam is placed between them. During foundation pit excavation, the servo steel support beam pushes the second block, controlling soil deformation in the area surrounding the existing structure and implementing differentiated resistance compensation for regional deformation risks of the existing structure. After foundation pit excavation is completed, grouting is performed between the first and second blocks to connect them as a whole. Internal support conversion is then performed, with support shifting from the second block to the entire structure. This provides stronger support in high-risk areas, preventing excessive deformation in these areas. Other areas, acting as low-risk zones, are also protected from material waste. Ultimately, a disturbance-free transition from a "discrete block" support system to a "monolithic continuous wall" is achieved.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, an intelligent support system for a foundation pit adjacent to an existing structure is provided, comprising a retaining unit outside the foundation pit, with a support unit disposed within the retaining unit. The retaining unit includes a first block for controlling deformation of soil in a general area surrounding the foundation pit, and a second block for controlling deformation of soil in the existing structure adjacent to the foundation pit. The first block is provided with a receiving groove matching the contour of the second block. The second block is provided with a plurality of parallel supports on a side facing the first block, with a plurality of support holes disposed within the receiving groove. The area of the second block is smaller than the area of the side on which the receiving groove is located.

[0009] The support unit includes a plurality of horizontal support systems. At the corresponding position of the second block, each horizontal support system includes a plurality of servo steel support beams arranged between the first block and the second block; one end of the servo steel support beam passes through the support hole and contacts the support;

[0010] The servo steel support beam includes a first component passed through a second component, a first servo cylinder group is arranged between the first component and the second component, the first servo cylinder group is fixedly connected to the second component and is not connected to the first component, and the end of the second component away from the first component is fixedly connected to the third component through the second servo cylinder group.

[0011] Preferably, each of the horizontal support systems includes a purlin arranged along the circumference of the inner wall of the first block, and a plurality of parallel ordinary steel support beams are arranged between the short side of the first block and the long side away from the existing structure for support. Steel columns are provided at the bottom of the ordinary steel support beams and the servo steel support beams, which together constitute a vertical bearing system.

[0012] Preferably, a plurality of parallel grooves are provided in the accommodating groove, the number of the grooves is equal to that of the supports, the shapes and sizes match, and the positions correspond; a plurality of groups of support holes are evenly arranged horizontally in each groove, and a rubber sealing ring is provided on the inner wall of the support hole.

[0013] Preferably, it also includes a grouting unit, which includes a grouting machine, the grouting machine is connected to the grouting pipeline, and a plurality of grouting pipes are arranged on the grouting pipeline; a plurality of independent grouting channels are arranged in the second block, and grouting holes are arranged on the top of the grouting channels, and each grouting channel is provided with a plurality of slurry outlet holes at a non-support position on the surface facing the first block; each grouting pipe is tightly connected to each grouting channel.

[0014] Preferably, the second component includes a support plate, one end of which is fixed with two long rods, and the other end of which is fixed with two short rods; the first component is provided with two through-holes, and the long rods are passed through the through-holes;

[0015] The first servo oil cylinder group is fixedly connected to the support plate between the long rods; the third component includes two support rods, and a connecting rod is arranged between the support rods; the second servo oil cylinder group is fixedly connected between the short rod and the support rod.

[0016] Preferably, the end of the first component away from the second component is fixedly connected to the purlin, the long rod passes through the support hole and is supported on the support, and the end of the third component away from the second component is fixedly connected to the purlin; both ends of the ordinary steel support beam are anchored to the purlin.

[0017] Preferably, it also includes an intelligent monitoring unit, which includes several serial fixed inclinometers arranged in the soil layer between the foundation pit and the existing structure; the serial fixed inclinometers are connected to the base station through a communication connection, and the base station is respectively communicated with the monitoring platform and the servo cylinder group in the servo steel support beam.

[0018] Secondly, a construction method for the above-mentioned intelligent support system for foundation pits close to existing structures is provided, which is specifically as follows:

[0019] S1. Install several serial fixed inclinometers between the existing structure and the foundation pit, then install a base station, and establish communication connections between the base station and the serial fixed inclinometers, the servo steel support beam, and the monitoring platform;

[0020] S2. Excavate a guide trench around the foundation pit and build a guide wall. Excavate the trench in sections. After excavating and cleaning each section, insert a joint pipe. Hoist the reinforcement cages of the first and second blocks into the trench. Pour concrete underwater through the guide pipe. Remove the joint pipe. Repeat the above process to complete the construction of all sections.

[0021] S3. After the retaining unit is cured, the foundation pit is excavated. After excavation to the specified depth, the support holes are cleaned and rubber sealing rings are laid. At the same time, the first horizontal support system is installed. Then, the excavation is continued to a deeper specified position and the above steps are repeated until the last horizontal support system is installed.

[0022] S4. After the foundation pit is excavated, the grouting unit is installed and grouting is performed between the first block and the second block to connect the two into a whole, and finally the internal support is replaced;

[0023] S5. When the project is completed, the support units shall be dismantled in sequence according to the construction requirements, and concrete shall be poured at the position of the support holes after dismantling to fill the gaps.

[0024] Preferably, in said S3, when the foundation pit is excavated downward, when the deformation of the soil around the existing structure is too large, the monitoring platform issues a loading instruction to the servo steel support beam of the horizontal support system at the corresponding position of the second block based on the data monitored by the serial fixed inclinometer; in this process, the second servo cylinder group pushes the second component toward the support, thereby pushing the second block to move toward the existing structure; at the same time, the first servo cylinder group contracts to avoid contact with the first component.

[0025] Preferably, in said S4, the specific steps of the internal support conversion are: controlling the servo steel support beam of the horizontal support system at the corresponding position of the second block through the monitoring platform, so that the first servo cylinder group inside it is started and contacts the first component, and force is applied to the purlin through the first component; at the same time, the force output of the first servo cylinder group and the second servo cylinder group is controlled in real time to ensure that the support stress of the first component and the second component remain consistent, thereby achieving smooth replacement of the internal support.

[0026] Compared with the prior art, the present invention has the following advantages and positive effects:

[0027] First, by connecting a serial fixed inclinometer, a servo steel support beam and a monitoring platform, the present invention can monitor the deformation of the soil around the foundation pit in real time, promptly capture sudden displacement changes, and take timely adjustment measures around the existing structure based on the monitoring results to perform precise dynamic adjustments, effectively preventing the soil from exceeding the safety value and excessive deformation, thereby ensuring the stability of the foundation pit and surrounding structures.

[0028] Secondly, the present invention sets up a separate first block and a second block, and sets a servo steel support beam between the first block and the second block. During the excavation of the foundation pit, the servo steel support beam pushes the second block to control the deformation of the soil in the existing structure area, thereby realizing differentiated resistance compensation for the regional deformation risk of the existing structure; after the excavation of the foundation pit is completed, the first block and the second block are connected as a whole by grouting between the two, and then the internal support conversion is performed, so that the servo steel support beam supports the first block and turns to the whole. At this time, the outer side of the first block facing the existing structure is thicker than other surfaces, thereby providing stronger support in the high-risk area to prevent the occurrence of excessive deformation in the high-risk area. Other areas are low-risk areas and there will be no waste of materials; ultimately, the support system is transformed from "discrete blocks" to "integral continuous walls" without disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0030] Figure 1 is an overall schematic diagram of the support system of embodiment 1 or 2 of the present invention;

[0031] Figure 2 is an overall schematic diagram of the retaining unit of embodiment 1 or 2 of the present invention;

[0032] Figure 3 is a schematic diagram of a support hole according to embodiment 1 or 2 of the present invention;

[0033] Figure 4is an overall schematic diagram of the support unit of embodiment 1 or 2 of the present invention;

[0034] Figure 5 is an overall schematic diagram of the servo steel support beam of embodiment 1 or 2 of the present invention;

[0035] Figure 6 is an exploded view of the servo steel support beam of embodiment 1 or 2 of the present invention;

[0036] Figure 7 is a schematic diagram of an intelligent monitoring unit according to Embodiment 1 or 2 of the present invention;

[0037] Figure 8 is a schematic diagram of a grouting unit according to embodiment 1 or 2 of the present invention;

[0038] In the picture:

[0039] 1. Foundation pit; 2. Retaining unit; 21. First block; 211. Receiving groove; 212. Support hole; 213. Rubber sealing ring; 214. Groove; 22. Second block; 221. Support; 222. Grouting hole; 223. Grouting hole; 3. Support unit; 31. Ordinary steel support beam; 32. Servo steel support beam; 321. First component; 3211. Through hole; 3212. First leg; 322. Second component; 3221. Support plate; 3222, long rod; 3223, short rod; 323, third component; 3231, support rod; 3232, connecting rod; 3233, second support leg; 324, first servo cylinder group; 325, second servo cylinder group; 33, steel column; 34, purlin; 4, intelligent monitoring unit; 41, serial fixed inclinometer; 42, base station; 43, monitoring platform; 5, grouting unit; 51, grouting machine; 52, grouting pipeline; 53, grouting pipe; 6, existing structure. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0041] The present invention will be described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] This embodiment discloses an intelligent support system for foundation pits close to existing structures, such as Figure 1As shown, the system comprises a retaining unit 2, a support unit 3, an intelligent monitoring unit 4, and a grouting unit 5. The retaining unit 2 is located outside the foundation pit 1 to resist lateral soil pressure and maintain soil stability. Specifically, the foundation pit 1 is excavated on one side of the existing structure 6, with the retaining unit 2 located outside the pit 1 and the support unit 3 located inside the retaining unit 2. The intelligent monitoring unit 4 includes a series of fixed inclinometers 41, several of which are located in the soil layer between the existing structure 6 and the foundation pit 1 to collect real-time soil deformation data between the existing structure 6 and the foundation pit 1. A grouting unit 5 is also located above the retaining unit 2 on the side facing the existing structure 6.

[0044] Specifically, if Figure 2 As shown, the retaining unit 2 is composed of an underground continuous wall, which is used to resist the lateral pressure of the soil and maintain soil stability. In order to achieve deformation control in different areas, the underground continuous wall is divided into two independent deformation control blocks, namely a first block 21 for controlling the deformation of the soil in the general area around the foundation pit 1, and a second block 22 specifically for controlling the deformation of the soil of the existing structure 6 adjacent to the foundation pit 1. Among them, the first block 21 is the main block. On the side of the first block 21 facing the existing structure 6, the area of the second block 22 is smaller than the area of the side of the first block 21. That is, in the vertical direction, the height of the second block 22 is smaller than the height of the first block 21, and in the horizontal direction, the length of the second block 22 is smaller than the length of the first block 21.

[0045] like Figure 2 As shown, the second block 22 is separated from the first block 21. On the outer wall of the first block 21 facing the existing structure 6, a receiving groove 211 is provided that matches the contour of the second block 22. Within the receiving groove 211, a plurality of supporting holes 212 are opened on the first block 21.

[0046] like Figure 2 As shown, a plurality of parallel supports 221 are provided on the surface of the second block 22 facing the first block 21. In this embodiment, two supports 221 are provided. It is understood that in other embodiments, more supports 221 may be provided. It is also understood that a plurality of parallel grooves 214 are provided inside the receiving groove 211. The number of grooves 214 is equal to the number of supports 221. The shapes and sizes of the grooves 214 and the supports 221 match, and the positions correspond. Figure 2 、 Figure 3As shown, support holes 212 are arranged within grooves 214, with each groove 214 having several groups of support holes 212 evenly spaced horizontally. Rubber sealing rings 213 are also provided on the inner walls of the support holes 212 to prevent groundwater from seeping into the retaining element 2 through the support holes 212. In this embodiment, when the first block 21 and the second block 22 are combined, the retaining element 2 is a hollow rectangular parallelepiped without an upper surface.

[0047] Multiple independent grouting channels are provided in the second block 22, specifically Figure 2 As shown, a grouting hole 222 is provided on the top of each grouting channel, and a plurality of slurry outlet holes 223 are provided on the surface of each grouting channel facing the first block 21 at a non-support position; in this embodiment, slurry outlet holes are provided above the first support and between the first support and the second support. It can be understood that in other embodiments, slurry outlet holes can also be provided below the second support.

[0048] It can be understood that grouting is performed into the grouting channel through the grouting hole 222, and the slurry flows out from the slurry outlet hole 223, filling the area between the first block 21 and the second block 22. After the slurry is finally solidified, a continuous solidified body is formed, so that the first block 21 and the second block 22 are connected, and the two independent support blocks are transformed into an integral load-bearing structure, while improving the stability and anti-seepage performance of the support system.

[0049] like Figure 4 As shown, a support unit 3 is provided inside the retaining unit 2, and the support unit 3 includes an ordinary steel support beam 31, a servo steel support beam 32, a steel column 33, and a purlin 34. Specifically, a number of horizontal support systems are provided inside the foundation pit 1, that is, inside the retaining unit 2. In this embodiment, three horizontal support systems are provided in the vertical direction. It can be understood that in other embodiments, four, five or more horizontal support systems can be provided. More specifically, three purlins 34 are evenly provided along the circumference of the inner wall of the first block 21 to achieve uniform distribution of the load. In the horizontal direction, a plurality of parallel ordinary steel support beams 31 are arranged between the short side of the first block 21 and the long side away from the existing structure, and the two ends of the ordinary steel support beam 31 are anchored to the purlin 34.

[0050] like Figure 4 As shown, on the multiple horizontal support systems at the corresponding positions of the second block 22, multiple servo steel support beams 32 are set between the first block 21 and the second block 22. In this embodiment, servo steel support beams 32 are set on the upper two horizontal support systems, and three servo steel support beams 32 are set on each horizontal support system.

[0051] In this embodiment, three groups of support holes 212 are evenly arranged in the horizontal direction in each groove 214, that is, each groove 214 is evenly arranged in the horizontal direction with a number of support holes 212 equal to the number of servo steel support beams 32 on each horizontal support system.

[0052] like Figure 4 As shown, on the two horizontal support systems above, one end of the servo steel support beam 32 is fixed to the purlin 34, and the other end passes through the support hole 212 preset in the first block 21 and presses against the support 221 of the adjacent second block 22. Figure 4 As shown, since the second block 22 is vertically shorter than the first block 21, one or more horizontal support systems are located below the second block 22. In this embodiment, the lowest horizontal support system is located below the second block 22. The horizontal system below the second block 22 is configured as a conventional steel support beam, with both ends of the conventional steel support beam fixed to the perimeter purlin.

[0053] It can be understood that although several horizontal support systems are set up inside the retaining unit 2, since the height of the second block 22 is smaller than the height of the first block 21 in the vertical direction, only in the horizontal support system corresponding to the second block 22, one end of the servo steel support beam 32 passes through the preset support hole 212 of the first block 21 and presses against the support 221 of the adjacent second block 22.

[0054] like Figure 4 As shown, the bottoms of the common steel support beam 31 and the servo steel support beam 32 are both equipped with steel columns 33, which together constitute a vertical bearing system. Figure 4 As shown, the steel columns 33 include two uprights, with multiple crossarms fixedly positioned between them. The spacing between the crossarms is determined by the spacing between the horizontal support systems. The crossarms are used to support the standard steel support beams 31 or the servo steel support beams 32. The number of steel columns is set based on actual conditions. In this embodiment, the standard steel support beams include two crossbeams, with a number of short beams fixedly connected between the two crossbeams.

[0055] like Figure 5 、 Figure 6 As shown, the servo steel support beam 32 includes a first component 321, the first component 321 is passed through the second component 322, and a first servo cylinder group 324 is arranged between the first component 321 and the second component 322. The first servo cylinder group 324 is fixedly connected to the second component 322 and is not connected to the first component 321. The end of the second component 322 away from the first component 321 is fixedly connected to the third component 323 through the second servo cylinder group 325.

[0056] Specifically, the first component 321 defines two through-holes 3211, with first legs 3212 fixedly connected to both sides of the first component 321. The second component 322 includes a central support plate 3221, with two long rods 3222 fixedly mounted on one end of the support plate 3221 and two short rods 3223 fixedly mounted on the other end. The long rods 3222 are inserted through the through-holes 3211. It is understood that the spacing between the long rods 3222 is equal to the spacing between the through-holes 3211. A first servo cylinder assembly 324 is fixedly connected to one end of the support plate 3221 between the long rods 3222. The other end of the first servo cylinder assembly 324 can abut against the first component 321, rather than being fixedly connected. It is understood that when the first servo cylinder assembly 324 is activated, it can push the first component 321 away from the support plate 3221.

[0057] like Figure 5 、 Figure 6 As shown, the third assembly 323 includes two struts 3231, with a connecting rod 3232 disposed between the two struts 3231. A second leg 3233 is fixedly mounted at the junction of the connecting rod 3232 and the strut 3231. The spacing between the struts 3231 is equal to the spacing between the short rods 3223 and the long rods 3222. The two short rods 3223 correspond to the two struts 3231, and each short rod 3223 is connected to each strut 3231 via a second servo cylinder assembly 325. Specifically, the ends of the second servo cylinder assembly are fixedly connected to the short rods and the struts, respectively.

[0058] like Figure 2 、 Figure 4 、 Figure 5 As shown, the end of the first component 321 away from the second component 322 is fixedly connected to the purlin 34. The long rod 3222 of the second component 322 passes through the first component 321, then through the support hole 212 in the first block 21, and then rests on the support 221. The end of the third component 323 away from the second component 322 is fixedly connected to the purlin 34. It can be understood that the function of the first and second legs is to strengthen the connection between the ends of the servo steel support beam 32 and the purlin 34, while also preventing the servo steel support beam 32 from deviating to the sides, ensuring that the servo force is applied perpendicular to the long side of the first block 21.

[0059] The power of the servo steel support beam 32 is provided by the first servo oil cylinder group and the second servo oil cylinder group, and the axial load transmission and control functions are realized through the linkage of each component.

[0060] The servo cylinder assembly includes a servo hydraulic cylinder and a PLC controller. The servo hydraulic cylinder is a conventional technology and generally consists of a cover, a cylinder barrel, a piston rod, a piston assembly, a servo valve, a sensor assembly (displacement sensor, load cell), and a base. The servo valve and sensor assembly are both connected to the PLC controller. In this embodiment, the monitoring platform communicates with the servo cylinder assembly's PLC controller, specifically using an ESP32 wireless communication module.

[0061] like Figure 7 As shown, the intelligent monitoring unit 4 also includes a base station 42. The tandem fixed inclinometer 41 is connected to the base station 42 via a communication link, transmitting monitoring data to the base station 42. The base station 42 is then connected to the monitoring platform 43 and the servo cylinder group in the servo steel support beam. In this embodiment, six tandem fixed inclinometers 41 are installed. Six holes are drilled at appropriate locations between the existing structure 6 and the foundation pit 1, and the six tandem fixed inclinometers are then installed in each of the holes. The base station 42 should be placed at a suitable location on the construction site to serve as a signal relay station. A communication link is then established between the tandem fixed inclinometer 41 and the base station 42, which is then connected to the servo cylinder group and the monitoring platform.

[0062] Based on the concept of digital twins, a monitoring model corresponding to the actual foundation pit project was created using Revit-BIM modeling software and imported into the monitoring platform 43. Next, the control system for the servo steel support beams and the data analysis system for the tandem fixed inclinometer 41 were written into the monitoring model.

[0063] During the monitoring process, the tandem fixed inclinometer 41 collects soil deformation data in real time and transmits it to the base station 42. The base station 42 then transmits this data to the monitoring platform 43, which organizes and analyzes the data and imports it into the monitoring model for visualization. Simultaneously, the monitoring platform issues control instructions based on the analysis results. These instructions are transmitted via the base station 42 to the PLC controller of the servo steel support beam 32, which drives the corresponding servo cylinder group to control the movement of the servo steel support beam, forcing the servo steel support beam 32 to push forward into the second block 22, thereby controlling soil deformation between the existing structure 6 and the foundation pit 1.

[0064] During this process, the loading data from the servo steel support beam 32 is again transmitted via base station 42 to monitoring platform 43. Monitoring platform 43 further analyzes and organizes the data and updates it to the monitoring model, visualizing the loading data. Meanwhile, the tandem fixed inclinometer 41 continues to monitor soil deformation and transmits this data to base station 42, which in turn feeds it to monitoring platform 43, which updates the monitoring model and completes a real-time closed-loop feedback loop. This process enables precise control and adjustment based on real-time data acquisition and processing, enabling dynamic monitoring and intelligent management of the foundation pit support structure.

[0065] By connecting the serial fixed inclinometer, servo steel support beam and monitoring platform, it is possible to monitor the deformation of the soil around the foundation pit in real time, promptly capture sudden displacement changes, and take timely adjustment measures around the existing structure based on the monitoring results for precise dynamic adjustments, effectively preventing the soil from exceeding the safety value and excessive deformation, and ensuring the stability of the foundation pit and surrounding structures.

[0066] like Figure 8 As shown, the grouting unit 5 includes a grouting machine 51, which is connected to a grouting pipeline 52. The grouting pipeline 52 is provided with a plurality of grouting pipes 53. Each grouting pipe 53 is tightly connected to a grouting hole 222, so that the grouting pipes 53 correspond to the grouting channels one by one. After the support is completed, the grouting machine 51 injects cement-based slurry into the structural gap between the first block 21 and the second block 22 through the grouting pipeline 52. The grouting pressure is controlled within the range of 0.5-1.2MPa. After the slurry is completely set, a continuous solid body is formed, which transforms the two independent support blocks into an integral load-bearing structure, while improving the stability and anti-seepage performance of the support system.

[0067] Example 2

[0068] This embodiment discloses a construction method of an intelligent support system for a foundation pit close to an existing structure, which utilizes the intelligent support system for a foundation pit close to an existing structure disclosed in Example 1, and is specifically as follows:

[0069] S1. First, install the intelligent monitoring system; first install the serial fixed inclinometer 41 between the existing structure 6 and the foundation pit 1, then install the base station 42, and make the base station communicate with the serial fixed inclinometer 41, the servo steel support beam 32 and the monitoring platform 43 respectively.

[0070] It is understandable that in this process, a monitoring model corresponding to the actual foundation pit project was established using Revit-BIM modeling software and has been imported into the monitoring platform 43.

[0071] S2. Then, the underground continuous wall is poured. First, the steel cages of the first block 21 and the second block 22 are made (during the production process, it is necessary to ensure that the specifications, types and welding quality of the steel bars meet the design requirements), support holes 212 are reserved at the predetermined positions of the steel cages of the first block 21, and formwork is constructed for the support holes 212. Simultaneously, the steel cages of the second block 22 are made, grouting holes 222 and grouting holes 223 are reserved at the corresponding positions, and grouting channels are pre-buried. The steel cages of the first block 21 and the second block 22 are simply spliced together, and a partition is set between the two to prevent them from mixing during pouring and to facilitate separation later.

[0072] Guide trenches are excavated around the foundation pit and guide walls are constructed. After the guide walls reach the designed strength, the formwork is removed and support treatment is completed before backfilling. Next, trench excavation is carried out. Before construction, the trench sections are divided according to requirements. The length of the underground continuous wall unit trench section should be controlled within the range of 4-6m. Mud is injected simultaneously during the excavation process to ensure that the mud surface in the trench is always 0.2m below the guide wall surface and 1m above the groundwater level.

[0073] After each section is excavated, the silt and debris at the bottom of the trench are cleaned and the slurry in the trench is replaced with circulating slurry. A joint pipe is then inserted, and the steel cages of the first block 21 and the second block 22 are hoisted into the trench. Finally, underwater concrete is poured through the guide tube, and the joint pipe is removed.

[0074] Repeat the above steps to complete the construction of all trench sections.

[0075] S3. After the curing of the first block 21 and the second block 22 is completed, the foundation pit is excavated and supported. After excavation to the specified depth according to the construction requirements, the support holes 212 reserved in the first block 21 are cleaned, and then rubber sealing rings 213 are laid to waterproof the support holes 212. At the same time, the ordinary steel support beams 31, servo steel support beams 32, steel columns 33, and surrounding purlins 34 are assembled, and the first horizontal support system is installed.

[0076] After the first horizontal support system is completed, continue to excavate to a deeper designated position, repeat the above steps, and install the second horizontal support system; then continue to excavate to a deeper designated position, repeat the above steps until all horizontal support systems are installed. Figure 3 、 Figure 4 As shown;

[0077] It is important to note that the intelligent monitoring unit also starts working during the excavation process. As the depth of the foundation pit increases, the lateral earth pressure gradually increases, and the deformation of the surrounding soil also intensifies. Since the allowable deformation of the soil in the general area is relatively large, the support of the first block 21 can meet the requirements.

[0078] However, the soil around the existing structure 6 is allowed to deform relatively little, and the support of the first block 21 alone cannot meet the requirements. When the soil deformation around the existing structure 6 is too large, the serial fixed inclinometer 41 transmits the real-time monitored data to the monitoring platform 43 via the base station 42; after receiving the data, the monitoring platform 43 issues a loading instruction to the servo steel support beam 32 of the horizontal support system located at the corresponding position of the second block through the base station 42 (that is, the servo steel support beam in the horizontal support system located below the second block will not receive the instruction), and the first servo cylinder group and the second servo cylinder group in the corresponding servo steel support beam 32 will start working.

[0079] Specifically, during this process, the second servo cylinder group will push the second component toward the first component, act on the support of the second block, and then push the second block to move toward the existing structure. However, during this process, the first servo cylinder group is contracted, and it is necessary to avoid contact between the first servo cylinder group and the first component, so as to achieve effective control of soil deformation between the existing structure and the foundation pit.

[0080] S4. After the excavation of the foundation pit is completed, the grouting unit is installed and grouting is carried out, and then the internal support is replaced; the grouting unit is connected to the second block 22, and then the grouting machine is turned on to inject cement-based slurry into the structural gap between the first block 21 and the second block 22. The grouting pressure is controlled within the range of 0.5-1.2MPa; after the slurry is finally set, a continuous solidified body is formed, and the two independent support blocks are transformed into an integral load-bearing structure, while improving the stability and anti-seepage performance of the support system.

[0081] Next, the support switching operation is performed. The monitoring platform 43 controls the servo steel support beam of the horizontal support system located at the corresponding position in the second block, activating the first servo cylinder group within it and contacting the first assembly. This first assembly then applies force to the perimeter purlin 34. Simultaneously, the force output of the first and second servo cylinder groups is controlled in real time to ensure consistent support stresses in the first and second assemblies, thus enabling smooth replacement of the internal supports.

[0082] It should be noted that under the push of the long rod, the gap between the first block and the second block is not large, only a few centimeters. The internal support conversion is carried out after the grouting solidifies. The long rod does not need to be pulled out during the internal support conversion. During adjustment, the stress output of the long rod and the first component will not have a large displacement, only a few millimeters; when the long rod is removed later, it will not be impossible to pull it out.

[0083] S5. Finally, when the project is finished, the support units are removed in sequence according to the construction requirements, and concrete is poured at the positions of the removed support holes 212 to fill the gaps and complete the construction.

[0084] It is not difficult to understand that by setting up separate first and second blocks, and setting up a servo steel support beam between the first and second blocks, the servo steel support beam is used to push the second block during the foundation pit excavation process, thereby controlling the soil deformation in the existing structure area and implementing differentiated resistance compensation for the regional deformation risk of the existing structure. After the foundation pit excavation is completed, the first and second blocks are connected as a whole by grouting between them, and then the internal support conversion is performed so that the servo steel support beam supports the first block. At this time, the outer side of the first block facing the existing structure is thicker than other sides, thereby providing stronger support in the high-risk area to prevent the occurrence of excessive deformation in the high-risk area. Other areas are low-risk areas, and there will be no waste of materials.

[0085] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. An intelligent support system for foundation pits adjacent to existing structures, comprising a retaining unit outside the foundation pit, a support unit disposed within the retaining unit, and characterized in that: The retaining unit includes a first block and a second block that are separated from each other; a receiving groove is provided on the first block, and a plurality of parallel supports are provided on the second block, and a plurality of supporting holes are provided in the receiving groove; the area of the second block is smaller than the area of the side where the receiving groove is located, and the second block is separated from the first block; Multiple independent grouting channels are set in the second block, and grouting holes are set on the top of the grouting channels. Each grouting channel is provided with multiple grouting holes at non-support positions on the surface facing the first block; The support unit includes several horizontal support systems, each of which includes a purlin arranged along the perimeter of the inner wall of the first block. At the corresponding position of the second block, the horizontal support system includes multiple servo steel support beams between the first block and the second block; one end of the servo steel support beam passes through the support hole to contact the support; the end of the third component away from the second component is fixedly connected to the purlin; the end of the second component away from the third component passes through the support hole to contact the support; The servo steel support beam includes a first component that is passed through a second component, an end of the first component away from the second component is fixedly connected to the purlin, a first servo cylinder group is provided between the first and second components, the first servo cylinder group is fixedly connected to the second component and is not connected to the first component, and an end of the second component away from the first component is fixedly connected to the third component via the second servo cylinder group; The second servo cylinder group pushes the second component to move toward the first component. During this process, the first servo cylinder group does not contact the first component.

2. The intelligent support system for foundation pits close to existing structures according to claim 1, characterized in that: A plurality of parallel ordinary steel support beams are arranged between the short side of the first block and the long side away from the existing structure for support. Steel columns are provided at the bottom of the ordinary steel support beams and the servo steel support beams, together forming a vertical bearing system.

3. The intelligent support system for foundation pits close to existing structures according to claim 1, characterized in that: A plurality of parallel grooves are arranged in the accommodating groove, and the number of the grooves is equal to that of the supports, the shapes and sizes match, and the positions correspond; a plurality of groups of support holes are evenly arranged horizontally in each groove, and rubber sealing rings are arranged on the inner walls of the support holes.

4. The intelligent support system for foundation pits close to existing structures according to claim 1, characterized in that: It also includes a grouting unit, which includes a grouting machine. The grouting machine is connected to a grouting pipeline, and a plurality of grouting pipes are arranged on the grouting pipeline; each grouting pipe is tightly connected to each grouting channel.

5. The intelligent support system for foundation pits close to existing structures according to claim 1, characterized in that: The second component includes a support plate, one end of which is fixed with two long rods, and the other end of which is fixed with two short rods; the first component is provided with two through-holes, and the long rods are inserted into the through-holes; The first servo oil cylinder group is fixedly connected to the support plate between the long rods; the third component includes two support rods, and a connecting rod is arranged between the support rods; the second servo oil cylinder group is fixedly connected between the short rod and the support rod.

6. The intelligent support system for foundation pits close to existing structures according to claim 5, characterized in that: The long rod passes through the support hole and is placed on the support, and both ends of the ordinary steel support beam are anchored and connected to the surrounding purlin.

7. The intelligent support system for foundation pits close to existing structures according to claim 1, characterized in that: It also includes an intelligent monitoring unit, which includes several serial fixed inclinometers set in the soil layer between the foundation pit and the existing structure; the serial fixed inclinometers are connected to the base station through a communication connection, and the base station is respectively communicated with the monitoring platform and the servo cylinder group in the servo steel support beam.

8. A construction method for an intelligent support system for foundation pits close to existing structures according to any one of claims 1 to 7, characterized in that: The details are as follows: S1. Install several serial fixed inclinometers between the existing structure and the foundation pit, then install a base station, and establish communication connections between the base station and the serial fixed inclinometers, the servo steel support beam, and the monitoring platform; S2. Excavate a guide trench around the foundation pit and build a guide wall. Excavate the trench in sections. After excavating and cleaning each section, insert a joint pipe. Hoist the reinforcement cages of the first and second blocks into the trench. Pour concrete underwater through the guide pipe. Remove the joint pipe. Repeat the above process to complete the construction of all sections. S3. After the retaining unit is cured, the foundation pit is excavated. After excavation to the specified depth, the support holes are cleaned and rubber sealing rings are laid. At the same time, the first horizontal support system is installed. Then, the excavation is continued to a deeper specified position and the above steps are repeated until the last horizontal support system is installed. S4. After the foundation pit is excavated, the grouting unit is installed and grouting is performed between the first block and the second block to connect the two into a whole, and finally the internal support is replaced; S5. When the project is completed, the support units shall be dismantled in sequence according to the construction requirements, and concrete shall be poured at the position of the support holes after dismantling to fill the gaps.

9. The construction method of the intelligent support system for foundation pits close to existing structures according to claim 8, characterized in that: In S3, when the foundation pit is excavated downward, when the deformation of the soil around the existing structure is too large, the monitoring platform issues a loading instruction to the servo steel support beam of the horizontal support system at the corresponding position of the second block based on the data monitored by the serial fixed inclinometer; during this process, the second servo cylinder group pushes the second component toward the support, thereby pushing the second block to move toward the existing structure; at the same time, the first servo cylinder group contracts to avoid contact with the first component.

10. The construction method of the intelligent support system for foundation pits close to existing structures according to claim 8, characterized in that: In S4, the specific steps of internal support conversion are: controlling the servo steel support beam of the horizontal support system at the corresponding position of the second block through the monitoring platform, so that the first servo cylinder group inside it is started and contacts the first component, and force is applied to the purlin through the first component; at the same time, the force output of the first servo cylinder group and the second servo cylinder group is controlled in real time to ensure that the support stress of the first component and the second component remains consistent, thereby achieving smooth replacement of the internal support.

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