Intelligent supporting system close to existing structure foundation pit and construction method

Abstract

The invention discloses an intelligent supporting system for a foundation pit close to an existing structure and a construction method, and belongs to the technical field of foundation pit construction.The intelligent supporting system comprises a soil retaining unit on the outer side of the foundation pit, a supporting unit is arranged in the soil retaining unit, and the soil retaining unit comprises a first block and a second block; the area of the second block is smaller than that of the side surface of the accommodating groove; the supporting unit comprises a plurality of horizontal supporting systems, and the horizontal supporting systems comprise a plurality of servo steel supporting beams between the first block and the second block at the positions corresponding to the second block. In the foundation pit excavation process, the servo steel supporting beam pushes the second block, soil deformation of an existing structure area is controlled, and differentiated resistance compensation is implemented aiming at the area deformation risk of the existing structure. After foundation pit excavation is completed, after the first block and the second block are connected into a whole through grouting between the first block and the second block, stronger support is provided in a high-risk area, the situation that deformation of the high-risk area exceeds the limit is prevented, and the situation that materials are wasted in a low-risk area is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of foundation pit construction, and particularly relates to an intelligent support system and construction method for a foundation pit adjacent to an existing structure. Background Technique

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

[0003] With the continuous increase in the development density of urban underground space, the scenario of foundation pit engineering construction adjacent to existing buildings is increasing day by day. Traditional foundation pit support technologies (such as row pile support, diaphragm wall, steel support internal bracing system, etc.) expose significant technical limitations in complex environments: Firstly, the traditional rigid support system cannot be dynamically adjusted according to the change of soil stress, there is a problem of lag in deformation control, and the monitoring mainly relies on manual regular data collection, making it difficult to capture sudden displacement changes in time, resulting in the deformation of the existing structure exceeding the safety value; Secondly, the stiffness of the traditional support structure is fixed, and it is impossible to implement differential 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, higher-strength deformation suppression is required on this side, but conventional technologies still use uniform support parameters, resulting in deformation exceeding the limit in high-risk areas or material waste in low-risk areas. Summary of the Invention

[0004] In view of the above problems, the present invention provides an intelligent support system and construction method for a foundation pit adjacent to an existing structure. By connecting a series-fixed inclinometer, a servo steel support beam, and a monitoring platform, the deformation of the soil around the foundation pit is monitored in real time, and precise dynamic adjustment is carried out according to the monitoring results; a separate first block and a second block are set, and a servo steel support beam is set between the first block and the second block. During the excavation of the foundation pit, the second block is pushed by the servo steel support beam to control the deformation of the soil in the area of the existing structure, so as to implement differential resistance compensation for the regional deformation risks of the existing structure; after the excavation of the foundation pit is completed, the first block and the second block are connected into a whole by grouting between them, and then the internal support is converted, and the support is transferred from the second block to the whole, so as to provide stronger support in the high-risk area and prevent the deformation in the high-risk area from exceeding the limit. Other areas are used as low-risk areas, and there will be no material waste. Finally, the seamless conversion of the support system from "discrete blocks" to "integral diaphragm wall" is realized.

[0005] To achieve the above object, the present invention adopts the following technical solutions: 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, a support unit arranged inside the retaining unit, the retaining unit comprising a first block for controlling the deformation of soil in a general area around the foundation pit, and a second block for controlling the deformation of soil in an existing structure adjacent to the foundation pit; a receiving groove matching the contour of the second block is arranged on the first block, a plurality of parallel supports are arranged on a side of the second block facing the first block, and a plurality of support 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; 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 to contact the support. The servo steel support beam includes a first component inserted 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 an end of the second component away from the first component is fixedly connected to the third component through the second servo cylinder group.

[0006] 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, together forming a vertical bearing system.

[0007] Preferably, a plurality of parallel grooves are arranged 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 arranged on the inner wall of the support hole.

[0008] Preferably, it also includes a grouting unit, which includes a grouting machine, which is connected to a grouting pipeline, on which a plurality of grouting pipes are arranged; a plurality of independent grouting channels are arranged in the second block, 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; and each grouting pipe is tightly connected to each grouting channel.

[0009] Preferably, the second component comprises 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 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 cylinder group is fixedly connected between the short rod and the support rod.

[0010] Preferably, one end of the first component away from the second component is fixedly connected to the waling beam. The long rod passes through the support hole and abuts against the support. One end of the third component away from the second component is fixedly connected to the waling beam. Both ends of the common steel support beam are anchored to the waling beam.

[0011] Preferably, it further includes an intelligent monitoring unit. The intelligent monitoring unit includes a number of series-connected fixed inclinometers arranged in the soil layer between the foundation pit and the existing structure. The series-connected fixed inclinometers are connected to the base station through communication, and the base station is respectively communicatively connected to the monitoring platform and the servo oil cylinder group in the servo steel support beam. In a second aspect, a construction method of the intelligent support system for a foundation pit adjacent to an existing structure as described above is provided, specifically as follows: S1. Install a number of series-connected fixed inclinometers between the existing structure and the foundation pit, then install the base station, and communicatively connect the base station to the series-connected fixed inclinometers, the servo steel support beam, and the monitoring platform respectively. S2. Excavate guide ditches around the foundation pit and build guide walls, and carry out trench excavation construction in sub-groove sections. After each section is excavated and cleaned, insert a joint pipe, hoist the steel reinforcement cages of the first block and the second block into the trench, perform underwater concrete pouring through a conduit, and pull out the joint pipe. Repeat the above process to complete the construction tasks of all trench sections. S3. After the retaining unit is cured, carry out the excavation of the foundation pit. After excavating to the specified depth, clean the support holes and lay rubber sealing rings, and at the same time install the first horizontal support system. Then continue to excavate to a deeper specified position, and repeat the above steps until the last horizontal support system is installed. S4. After the excavation of the foundation pit is completed, install the grouting unit and grout between the first block and the second block to connect them as a whole, and finally carry out the replacement of the internal support. S5. At the end of the project, remove the support units in sequence according to the construction requirements, and pour concrete at the positions of the support holes after removal to fill the gaps.

[0012] Preferably, in the step S3, when the foundation pit is excavated downward and the soil deformation amount 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 according to the data monitored by the series-connected fixed inclinometers. In this process, the second servo oil cylinder group pushes the second component towards the support, thereby pushing the second block towards the existing structure; at the same time, the first servo oil cylinder group contracts to avoid contacting the first component.

[0013] Preferably, 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 with 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.

[0014] Compared with the prior art, the present invention has the following advantages and positive effects: Firstly, by connecting a series 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 adjustment measures around the existing structure in time according to the monitoring results for precise dynamic adjustment, effectively preventing the soil from exceeding the safety value and excessive deformation, thereby ensuring the stability of the foundation pit and surrounding structures. 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 foundation pit excavation process, the second block is pushed by the servo steel support beam to control the soil deformation in the existing structure area, thereby realizing differentiated resistance compensation for the regional deformation risk of the existing structure; after the foundation pit excavation 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. As other areas are low-risk areas, there will be no waste of materials; finally, the support system is transformed from "discrete blocks" to "integral continuous walls" without disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings in the specification, 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.

[0016] Figure 1 is an overall schematic diagram of the support system of Embodiment 1 or 2 of the present invention; Figure 2 is an overall schematic diagram of a retaining unit according to Embodiment 1 or 2 of the present invention; Figure 3 is a schematic diagram of a support hole in Embodiment 1 or 2 of the present invention; Figure 4 is an overall schematic diagram of a support unit according to Embodiment 1 or 2 of the present invention; Figure 5 is an overall schematic diagram of a servo steel support beam according to Embodiment 1 or 2 of the present invention; Figure 6 is an exploded view of the servo steel support beam of Embodiment 1 or 2 of the present invention; Figure 7 is a schematic diagram of the intelligent monitoring unit of Embodiment 1 or 2 of the present invention; Figure 8 is a schematic diagram of the grouting unit of Embodiment 1 or 2 of the present invention; In the figure: 1. Foundation pit; 2. Retaining unit; 21. First block; 211. Accommodating groove; 212. Support hole; 213. Rubber sealing ring; 214. Groove; 22. Second block; 221. Support; 222. Grouting hole; 223. Grout outlet hole; 3. Support unit; 31. Ordinary steel support beam; 32. Servo steel support beam; 321. First component; 3211. Penetrating hole; 3212. First leg; 322. Second component; 3221. Support plate; 3222. Long rod; 3223. Short rod; 323. Third component; 3231. Strut; 3232. Link; 3233. Second leg; 324. First servo cylinder group; 325. Second servo cylinder group; 33. Steel column; 34. Waling; 4. Intelligent monitoring unit; 41. Series fixed inclinometer; 42. Base station; 43. Monitoring platform; 5. Grouting unit; 51. Grouting machine; 52. Grout conveying pipeline; 53. Grouting pipe; 6. Existing structure. Detailed implementation manners

[0017] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0018] The present invention will be described in detail below with reference to the accompanying drawings.

[0019] Embodiment 1 A near-existing structure foundation pit intelligent support system disclosed in this embodiment, as Figure 1 shown, includes a retaining unit 2, a support unit 3, an intelligent monitoring unit 4, and a grouting unit 5. Among them, the retaining unit 2 is arranged on the outer side of the foundation pit 1 to resist the lateral pressure of the soil and maintain the stability of the soil; specifically, a foundation pit 1 is dug on one side of the existing structure 6, the retaining unit 2 is arranged on the outer side of the foundation pit 1, and the support unit 3 is arranged inside the retaining unit 2; the intelligent monitoring unit 4 includes a series fixed inclinometer 41, and a plurality of series fixed inclinometers 41 are arranged in the soil layer between the existing structure 6 and the foundation pit 1 to collect the soil deformation data between the existing structure 6 and the foundation pit 1 in real time. A grouting unit 5 is also arranged above the side of the retaining unit 2 facing the existing structure 6.

[0020] Specifically, asFigure 2 As shown, the retaining unit 2 is composed of a diaphragm wall, which functions to resist the lateral pressure of the soil mass and maintain the stability of the soil mass. In order to achieve deformation control in different regions, the diaphragm wall is divided into two independent deformation control blocks, namely the first block 21 for controlling the deformation of the soil mass in the general area around the foundation pit 1, and the second block 22 specifically for controlling the deformation of the soil mass 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 this side surface 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.

[0021] As Figure 2 shown, the second block 22 is a piece separated from the first block 21. On the outer wall of the first block 21 facing the existing structure 6, a receiving groove 211 matching the contour of the second block 22 is provided. In the receiving groove 211, a number of support holes 212 are opened on the first block 21.

[0022] As Figure 2 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 can be understood that in other embodiments, more supports 221 can also be provided. It can also be understood that a number 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 grooves 214 match the shape and size of the supports 221 and are in corresponding positions. As Figure 2 、 Figure 3 shown, the support holes 212 are provided in the grooves 214. A number of groups of support holes 212 are evenly provided in the horizontal direction in each groove 214. At the same time, a rubber sealing ring 213 is provided on the inner wall of the support hole 212 to prevent groundwater from seeping into the interior of the retaining unit 2 through the support holes 212. In this embodiment, when the first block 21 and the second block 22 are combined together, the retaining unit 2 is a hollow cuboid without an upper surface.

[0023] A number of independent grouting channels are provided in the second block 22. Specifically, as Figure 2 shown, a grouting hole 222 is provided at the top of each grouting channel. On the surface of each grouting channel facing the first block 21, a plurality of slurry outlet holes 223 are provided at non-support positions; 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.

[0024] It is understandable that grout is injected into the grouting channel through the grouting holes 222, and the grout flows out from the grout outlet holes 223 to fill the area between the first block 21 and the second block 22. After the grout finally sets, a continuous consolidated body is formed, enabling the connection between the first block 21 and the second block 22, transforming the two independent support blocks into an integral stress-bearing structure, and simultaneously enhancing the stability and anti-seepage performance of the support system.

[0025] As Figure 4 shown, a support unit 3 is arranged inside the retaining unit 2. The support unit 3 includes a common steel support beam 31, a servo steel support beam 32, a steel column 33, and a waling 34. Specifically, inside the foundation pit 1, that is, inside the retaining unit 2, several horizontal support systems are arranged. In this embodiment, three horizontal support systems are arranged in the vertical direction. It is understandable that in other embodiments, the horizontal support system can be arranged with four, five or more channels. More specifically, three waling 34 are evenly arranged along the inner wall perimeter of the first block 21 to achieve uniform load distribution. Horizontally, between the short side of the first block 21 and the long side away from the existing structure, multiple parallel common steel support beams 31 are arranged in a cross-bracing manner, and both ends of the common steel support beam 31 are anchored to the waling 34.

[0026] As Figure 4 shown, on the multiple horizontal support systems at the corresponding positions of the second block 22, multiple servo steel support beams 32 are arranged between the first block 21 and the second block 22. In this embodiment, servo steel support beams 32 are arranged on the upper two horizontal support systems, and on each horizontal support system, three servo steel support beams 32 are arranged.

[0027] In this embodiment, three groups of support holes 212 are evenly arranged in the horizontal direction in each groove 214, that is, in the horizontal direction of each groove 214, several groups of support holes 212 equal to the number of servo steel support beams 32 on each horizontal support system are evenly arranged.

[0028] As Figure 4 shown, on the upper two horizontal support systems, one end of the servo steel support beam 32 is fixed to the waling 34, and the other end passes through the preset support holes 212 of the first block 21 and abuts against the support 221 of the adjacent second block 22. As Figure 4 shown, since the height of the second block 22 is less than that of the first block 21 in the vertical direction, there will be one or more horizontal support systems located below the second block 22. In this embodiment, the lowermost horizontal support system is located below the second block 22. In the horizontal system located below the second block 22, it is set as a common steel support beam, and both ends of the common steel support beam in the horizontal system located below the second block 22 are fixed to the waling.

[0029] It can be understood that although several horizontal support systems are provided inside the retaining unit 2, since the height of the second block 22 is less than that 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 abuts against the support 221 of the adjacent second block 22.

[0030] As Figure 4 shown, steel columns 33 are arranged at the bottoms of both the ordinary steel support beam 31 and the servo steel support beam 32, jointly constituting a vertical load-bearing system. Specifically, as Figure 4 shown, the steel column 33 includes two columns, and a plurality of crossbars are fixedly arranged between the two columns. The distance between the crossbars is determined by the distance between the horizontal support systems, and the crossbars are used to support the ordinary steel support beam 31 or the servo steel support beam 32. The number of steel columns is set according to the actual situation. In this embodiment, the ordinary steel support beam includes two crossbeams, and a plurality of short beams are fixedly connected between the two crossbeams.

[0031] As Figure 5 、 Figure 6 shown, the servo steel support beam 32 includes a first component 321, the first component 321 is sleeved on the second component 322, a first servo oil cylinder group 324 is arranged between the first component 321 and the second component 322, the first servo oil cylinder group 324 is fixedly connected to the second component 322 and is not connected to the first component 321, and one end of the second component 322 away from the first component 321 is fixedly connected to a third component 323 through a second servo oil cylinder group 325.

[0032] Specifically, two through holes 3211 are formed in the first component 321, and first legs 3212 are fixedly connected to both sides of the first component 321. The second component 322 includes a middle support plate 3221, two long rods 3222 are fixedly arranged at one end of the support plate 3221, and two short rods 3223 are fixedly arranged at the other end. The long rods 3222 are sleeved in the through holes 3211. It can be understood that the distance between the long rods 3222 is equal to the distance between the through holes 3211. At one end of the support plate 3221 between the long rods 3222, a first servo oil cylinder group 324 is fixedly connected, and the other end of the first servo oil cylinder group 324 can abut against the first component 321 instead of being fixedly connected. It can be understood that when the first servo oil cylinder group 324 starts to output, it can push against the first component 321 to move in a direction away from the support plate 3221.

[0033] As Figure 5 、 Figure 6As shown, the third component 323 includes two struts 3231. A connecting rod 3232 is arranged between the two struts 3231. At the connection of the connecting rod 3232 and the struts 3231, a second leg 3233 is fixedly arranged. The distance between the struts 3231 is equal to the distance between the short rods 3223 and is also equal to the distance between 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 through a second servo cylinder group 325. Specifically, the two ends of the second servo cylinder group are fixedly connected to the short rod and the strut respectively.

[0034] As Figure 2 , Figure 4 , Figure 5 As shown, one end of the first component 321 away from the second component 322 is fixedly connected to the waling 34. The long rod 3222 of the second component 322 passes through the first component 321, then passes through the support hole 212 on the first block 21, and then abuts against the support 221. One end of the third component 323 away from the second component 322 is fixedly connected to the waling 34. It can be understood that the functions of the first leg and the second leg are to strengthen the connection between the two ends of the servo steel support beam 32 and the waling 34, and at the same time prevent the servo steel support beam 32 from shifting towards both sides, ensuring that the servo force can be applied perpendicular to the long side of the first block 21.

[0035] The power of the servo steel support beam 32 is provided jointly by the first servo cylinder group and the second servo cylinder group, and the axial load transfer and control functions are realized through the linkage of each component.

[0036] The servo cylinder group includes: a servo hydraulic cylinder and a PLC controller; the servo hydraulic cylinder is a prior art and generally consists of main parts such as an end cover, a cylinder barrel, a piston rod, a piston assembly, a servo valve, a sensing assembly (displacement sensor, load sensor), a base, etc.; among them, the servo valve and the sensing assembly are both connected to the PLC controller. In this embodiment, the monitoring platform is communicatively connected to the PLC controller of the servo cylinder group. Specifically, an ESP32 wireless communication module can be used.

[0037] As Figure 7As shown in the figure, the intelligent monitoring unit 4 further includes a base station 42. The series fixed inclinometer 41 is communicatively connected to the base station 42 to transmit the monitored data information to the base station 42. The base station 42 is communicatively connected to the monitoring platform 43 and the servo oil cylinder group in the servo steel support beam respectively. In this embodiment, six series fixed inclinometers 41 are provided. At appropriate positions between the existing structure 6 and the foundation pit 1, six drill holes are drilled, and then the six series fixed inclinometers are respectively installed into the drill holes. The base station 42 should be placed at an appropriate position on the construction site as a signal transfer station. Then, a communication connection is established between the series fixed inclinometer 41 and the base station 42, and then the base station is communicatively connected to the servo oil cylinder group and the monitoring platform respectively.

[0038] Based on the concept of digital twin, a monitoring model corresponding to the actual foundation pit project is established using Revit-BIM modeling software and imported into the monitoring platform 43. Next, the control system of the servo steel support beam and the data analysis system of the series fixed inclinometer 41 are written into the monitoring model.

[0039] During the monitoring process, the series fixed inclinometer 41 real-time collects the soil deformation data and transmits the collected data to the base station 42. The base station 42 further transmits these data to the monitoring platform 43. The monitoring platform sorts and analyzes the data and imports it into the monitoring model to achieve the visual display of the data. At the same time, the monitoring platform issues control instructions according to the analysis results. The instructions are transmitted to the PLC controller of the servo steel support beam 32 through the base station 42 to drive the corresponding servo oil cylinder group to control the action of the servo steel support beam, so that the servo steel support beam 32 advances forward to the second block 22 to control the soil deformation between the existing structure 6 and the foundation pit 1.

[0040] In the above process, the loading data of the servo steel support beam 32 will be transmitted to the monitoring platform 43 through the base station 42 again. The monitoring platform 43 further analyzes and sorts the data and updates it to the monitoring model to achieve the visualization of the loading data. At this time, the series fixed inclinometer 41 continues to monitor the soil deformation and transmits the data to the base station 42 and then sends it to the monitoring platform 43 again to update the monitoring model and complete the real-time closed-loop feedback of the information. Through this process, the system can perform precise control and adjustment on the basis of real-time obtaining and processing data to achieve the dynamic monitoring and intelligent management of the foundation pit support structure.

[0041] By connecting the series fixed inclinometer, the servo steel support beam and the monitoring platform, it is possible to real-time monitor the deformation of the soil around the foundation pit, timely capture sudden displacement changes, and take adjustment measures in time around the existing structure according to the monitoring results for precise dynamic adjustment, effectively preventing the soil from deforming excessively beyond the safety value and ensuring the stability of the foundation pit and the surrounding structures.

[0042] Such asFigure 8 As shown in Figure 8 , the grouting unit 5 includes a grouting machine 51. The grouting machine 51 is connected to a slurry conveying pipeline 52. A number of grouting pipes 53 are arranged on the slurry conveying pipeline 52. Each grouting pipe 53 is hermetically 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 the cement-based slurry into the structural gap between the first block 21 and the second block 22 through the slurry conveying pipeline 52. The grouting pressure is controlled within the range of 0.5 - 1.2 MPa. After the slurry finally sets, a continuous consolidation body is formed, converting the two independent support blocks into an integral stress-bearing structure, and at the same time enhancing the stability and anti-seepage performance of the support system.

[0043] Embodiment 2 A construction method of an intelligent support system for a foundation pit adjacent to an existing structure disclosed in this embodiment uses an intelligent support system for a foundation pit adjacent to an existing structure disclosed in Embodiment 1, as follows: S1. First, install the intelligent monitoring system; first install the series-connected fixed inclinometer 41 between the existing structure 6 and the foundation pit 1, and then install the base station 42, and make the base station communicate with the series-connected fixed inclinometer 41, the servo steel support beam 32, and the monitoring platform 43 respectively.

[0044] It can be understood that in this process, a monitoring model corresponding to the actual foundation pit project is established using Revit - BIM modeling software and has been imported into the monitoring platform 43.

[0045] S2. Then, carry out the casting of the diaphragm wall; first fabricate the steel reinforcement cages of the first block 21 and the second block 22 (during the fabrication process, it is necessary to ensure that the steel bar specifications, models, and welding quality meet the design requirements). Reserve support holes 212 at the predetermined positions of the steel reinforcement cage of the first block 21, and carry out formwork construction for the support holes 212; synchronously fabricate the steel reinforcement cage of the second block 22, reserve grouting holes 222 and slurry outlet holes 223 at the corresponding positions, and embed grouting channels; simply splice the steel reinforcement cages of the first block 21 and the second block 22, and set a partition between the two to avoid being integrated during casting and facilitate later separation; Excavate guide ditches and build guide walls around the foundation pit. After the guide walls reach the design strength, remove the formwork and do a good job in support treatment, and finally backfill; then carry out trench excavation construction. Before construction, divide the trench sections as required. The length of the unit trench section of the diaphragm wall should be controlled within the range of 4 - 6 m. During the excavation process, inject slurry synchronously to ensure that the slurry surface in the trench is always 0.2 m below the guide wall surface and 1 m above the groundwater level; After the excavation of each section is completed, clean the silt and residues at the bottom of the trench, and use circulating slurry to replace the slurry in the trench; then insert the connector pipe, hoist the steel reinforcement cages of the first block 21 and the second block 22 into the trench, and finally carry out underwater concrete pouring through the conduit and pull out the connector pipe; Repeat the construction according to the above procedures to complete the construction tasks of all trench segments.

[0046] S3. After the curing of the first block 21 and the second block 22 is completed, carry out the excavation and support of the foundation pit; according to the construction requirements, after excavating to the specified depth, clean the reserved support holes 212 in the first block 21, and then lay the rubber sealing ring 213 for waterproofing the support holes 212; at the same time, assemble the ordinary steel support beams 31, the servo steel support beams 32, the steel columns 33, and the waling 34, and install the first horizontal support system. After the first horizontal support system is supported, continue to excavate to a deeper specified position, repeat the above steps, and install the second horizontal support system; then continue to excavate to a deeper specified position, repeat the above steps until all horizontal support systems are installed, as Figure 3 , Figure 4 shown. It should be noted that during the excavation of the foundation pit, the intelligent monitoring unit also starts to work synchronously. 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 ordinary area is relatively large, the support of the first block 21 can meet the requirements. However, the allowable deformation of the soil around the existing structure 6 is relatively small, and the support only relying on the first block 21 cannot meet the requirements. When the deformation of the soil around the existing structure 6 is too large, the series fixed inclinometer 41 transmits the real-time monitored data to the monitoring platform 43 through 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 at the corresponding position in the second block through the base station 42 (that is, the servo steel support beam in the horizontal support system below the second block will not receive the instruction), and the first servo oil cylinder group and the second servo oil cylinder group in the corresponding servo steel support beam 32 work.

[0047] Specifically, in this process, the second servo oil cylinder group will push the second component to move towards the first component, acting on the support of the second block, and then push the second block to move towards the existing structure. However, in this process, the first servo oil cylinder group is contracted, and it is necessary to avoid the contact between the first servo oil cylinder group and the first component, so as to effectively control the deformation of the soil between the existing structure and the foundation pit.

[0048] S4. After the excavation of the foundation pit is completed, install the grouting unit and carry out grouting, and then carry out the replacement of the internal support; connect the grouting unit with the second block 22, and then open the grouting machine to inject the cement-based slurry into the structural gap between the first block 21 and the second block 22, and control the grouting pressure within the range of 0.5 - 1.2 MPa; after the slurry finally sets, a continuous consolidated body is formed, transforming the two independent support blocks into an integral stress-bearing structure, and at the same time improving the stability and anti-seepage performance of the support system.

[0049] Next, perform the support conversion operation; control the servo steel support beam of the horizontal support system at the corresponding position of the second block through the monitoring platform 43, start the first servo oil cylinder group inside it and make contact with the first component, and apply force to the waling 34 through the first component. At the same time, control the force output of the first servo oil cylinder group and the second servo oil cylinder group in real time to ensure that the support stresses of the first component and the second component are consistent, so as to realize the smooth replacement of the internal support.

[0050] It should be noted that under the pushing action of the long rod, the gap between the first block and the second block is not large, only a few centimeters. After the grouting coagulates, the internal support is converted, and the long rod does not need to be withdrawn during the internal support conversion. During adjustment, the stress output of the long rod and the first component will not have large displacements, only a few millimeters; and there will be no situation where the long rod cannot be withdrawn during the later removal of the long rod.

[0051] S5. Finally, when the project is completed, remove the support units in sequence according to the construction requirements, and pour concrete at the position of the support hole 212 after removal to fill the gap and complete the construction.

[0052] It is not difficult to understand that by setting the separated first block and second block, and setting a servo steel support beam between the first block and the second block, during the foundation pit excavation process, the second block is pushed by the servo steel support beam to control the soil deformation in the area of the existing structure, so as to realize the differential resistance compensation for the regional deformation risk of the existing structure. After the foundation pit excavation is completed, after grouting between the first block and the second block to connect them into a whole, then perform the internal support conversion to make the servo steel support beam hold against the first block. At this time, the outer side of the first block facing the existing structure is thicker than other surfaces, so as to provide stronger support in the high-risk area and prevent the deformation in the high-risk area from exceeding the limit. As for other areas as low-risk areas, there will be no situation of material waste.

[0053] Although the specific implementation manners of the present invention are described above in conjunction with the drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. An intelligent support system for foundation pits close to existing structures, comprising a retaining unit outside the foundation pit, a support unit arranged inside the retaining unit, characterized in that: The retaining unit comprises a first block and a second block; a receiving groove is arranged on the first block, a plurality of parallel supports are arranged 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; The support unit includes a plurality of horizontal support systems. At the corresponding position of the second block, the horizontal support system includes a plurality of 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 servo steel support beam includes a first component inserted 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 an end of the second component away from the first component is fixedly connected to the third component through the second servo cylinder group.

2. The intelligent support system for foundation pit close to existing structure as claimed in claim 1, characterized in that: Each of the horizontal support systems includes a purlin arranged along the circumference of the inner wall of the first block. 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 arranged 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 pit close to existing structure as claimed in claim 1, characterized in that: A plurality of parallel grooves are arranged in the accommodating groove, the number of the grooves is equal to that of the supports, the shapes and sizes are matched, and the positions are corresponding; a plurality of groups of supporting holes are evenly arranged horizontally in each groove, and rubber sealing rings are arranged on the inner walls of the supporting holes.

4. The intelligent support system for foundation pit close to existing structure as claimed in claim 1, characterized in that: It also includes a grouting unit, which includes a grouting machine, which is connected to a grouting pipeline, on which a plurality of grouting pipes are arranged; a plurality of independent grouting channels are arranged in the second block, 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; and each grouting pipe is tightly connected to each grouting channel.

5. The intelligent support system for foundation pit close to existing structure as claimed in 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 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 cylinder group is fixedly connected between the short rod and the support rod.

6. The intelligent support system for foundation pit close to existing structure as claimed in claim 5, characterized in that: One end of the first component away from the second component is fixedly connected to the surrounding purlin, the long rod passes through the support hole and is supported on the support, and one end of the third component away from the second component is fixedly connected to the surrounding purlin; both ends of the ordinary steel support beam are anchored to the surrounding purlin.

7. The intelligent support system for foundation pit close to existing structure as claimed in claim 1, characterized in that: It also includes an intelligent monitoring unit, which includes a number of 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 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 as claimed in 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 make the base station communicate with the serial fixed inclinometers, the servo steel support beam, and the monitoring platform respectively; S2. Excavate the guide trench around the foundation pit and build the guide wall, and carry out trench excavation construction for the trench sections; after each section is excavated and cleaned, insert the joint pipe, hoist the steel cages of the first block and the second block into the trench, perform underwater concrete pouring through the guide tube, and pull out the joint pipe; repeat the construction according to the above process to complete the construction tasks of all trench 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, and the first horizontal support system is installed at the same time. 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 blocks as a whole, and finally the internal support is replaced; S5. At the end of the project, the support units shall be removed in sequence according to the construction requirements, and concrete shall be poured at the positions of the support holes after removal to fill the gaps.

9. The construction method of the intelligent support system for foundation pit close to existing structure as claimed in 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 tandem 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.

10. The construction method of the intelligent support system for foundation pit close to existing structure as claimed in claim 8, characterized in that: In S4, the specific steps of the internal support conversion are: control 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 with 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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