System and method for applying prestress to enclosure in foundation pit

Abstract

The invention discloses a system and a method for applying prestress to an enclosure in a foundation pit. The prestress applying system comprises a jacking device (1); the jacking device comprises a jacking base (11) and a jacking telescopic arm (12); a jacking base of the jacking device is assembled on a horizontal support (41) close to the pit bottom, and the jacking output end of a jacking telescopic arm can obliquely extend downwards and apply jacking prestress to the portion, close to the pit bottom, of the enclosure. The prestress applying method comprises the steps that the prestress applying system is installed on the basis of a near-pit-bottom horizontal support, and installation of the prestress applying system is completed before subsequent digging operation of a lower layer; and the pre-stress applying system is used for applying top supporting pre-stress to the part, close to the pit bottom, of the enclosure And the part, close to the pit bottom, of the enclosure can obtain the applied jacking prestress in the first time, so that the displacement deformation of the part, close to the pit bottom, of the enclosure can be corrected in time, and the overall engineering quality of the foundation pit engineering is improved.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit engineering, and in particular to a system and method for applying prestress to enclosures in a foundation pit. Background Art

[0002] Excavation of foundation pits will cause settlement and displacement of surrounding strata, thus affecting the safety of nearby subway tunnels and buildings. The main reason is that excavation of foundation pits will cause displacement and deformation of surrounding soil. Therefore, it is necessary to build a retaining support system during the construction of foundation pits to support the retaining structure around the foundation pits and ensure the safety of the surrounding environment.

[0003] In addition, a servo system will be installed on the retaining support system to actively apply top support prestress to the retaining structure to resist the displacement and deformation of the soil around the foundation pit.

[0004] The current problem is:

[0005] The existing servo system mainly realizes "applying lateral top support prestressing to the retaining structure". However, the process of excavating the foundation pit and constructing the lower-level foundation pit structure requires a long construction period. Before the lower-level foundation pit structure is completed, it is impossible to apply top support prestressing to the retaining near the bottom of the pit. As a result, the retaining near the bottom of the pit may be displaced and deformed before the lower-level foundation pit structure is completed, which is not conducive to the construction quality of the entire foundation pit project. Summary of the invention

[0006] The object of the present invention is to provide a system and method for applying prestress to retaining walls in a foundation pit, wherein the system and method for applying prestress can load top support prestress to retaining walls near the bottom of the pit based on horizontal supports near the bottom of the pit.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] A prestressing system for enclosure in a foundation pit, the prestressing system comprising a top support device;

[0009] The supporting device comprises a supporting base and a supporting telescopic arm;

[0010] One end of the top support telescopic arm serves as an assembly end, and the other end of the top support telescopic arm serves as a top support output end;

[0011] The assembly end of the top support telescopic arm is assembled and connected with the top support base.

[0012] The top support telescopic arm is provided with an angle adjustment mechanism, and the angle adjustment mechanism is used to drive the top support telescopic arm to swing up and down;

[0013] The top support base of the top support device is assembled on a horizontal support near the bottom of the pit, and the top support output end of the top support telescopic arm can extend toward the enclosure near the bottom of the pit and apply top support prestress to the enclosure near the bottom of the pit.

[0014] Furthermore, the prestressing system also includes an elevation adjustment device;

[0015] The elevation adjustment device includes a bearing seat and an elevation winch.

[0016] The load-bearing seat is pressed against the bottom of the enclosure near the pit, and the height-adjusting winch is used to drive the load-bearing seat to move up and down against the bottom of the enclosure near the pit;

[0017] The top support output end of the top support telescopic arm applies top support prestress to the surrounding area near the bottom of the pit through a load-bearing seat.

[0018] Furthermore, the height-adjusting winch is installed on a horizontal support near the pit bottom.

[0019] Furthermore, the force bearing seat has a force bearing surface, and the force bearing surface of the force bearing seat is inclined upward and faces the supporting base of the supporting device.

[0020] Furthermore, a top support end head is provided on the top support output end of the top support telescopic arm, and the top support end head is assembled on the top support output end of the top support telescopic arm through a shaft pin mechanism.

[0021] Furthermore, an inclinometer is provided for the retaining structure, and an axial force monitoring device is provided for the horizontal support near the bottom of the pit;

[0022] The prestressing system also includes a prestressing control computer, the supporting device and the elevation adjusting device are both controlled by the prestressing control computer, and the inclination measuring device and the axial force monitoring device are connected to the prestressing control computer by signal;

[0023] The prestress control computer can control the top support device and the elevation adjustment device to apply top support prestress to the surrounding area near the bottom of the pit according to the detection data of the inclinometer and the axial force monitoring device.

[0024] Furthermore, the top support base is assembled and arranged at the connection between the horizontal support near the bottom of the pit and the anti-pullout device.

[0025] Furthermore, the number of the jacking devices is two, and the jacking bases of the two jacking devices are respectively placed on both sides of the horizontal support near the bottom of the pit, and the jacking bases of the two jacking devices are connected together by fasteners. The jacking bases of the two jacking devices hold the horizontal support near the bottom of the pit mutually, thereby realizing the installation setting of the jacking base on the horizontal support near the bottom of the pit.

[0026] Furthermore, the angle adjustment mechanism is specifically implemented in the form of a structure in which an angle adjusting winch is configured for the top support telescopic arm, and the angle adjusting winch is installed on a horizontal support near the bottom of the pit, and a hoisting rope of the angle adjusting winch is connected to the top support output end of the top support telescopic arm. The hoisting and lifting action of the angle adjusting winch can drive the top support telescopic arm to swing up and down.

[0027] Furthermore, the angle-adjusting winch and the height-adjusting winch are the same winch.

[0028] A method for applying prestress to a retaining wall in a foundation pit, the method comprising:

[0029] S1, construct horizontal support near the bottom of the pit;

[0030] S2, installing a prestressing system based on the horizontal support near the bottom of the pit, and completing the installation of the prestressing system before the subsequent lower level excavation operation;

[0031] The prestressing system comprises a top support device;

[0032] The supporting device comprises a supporting base and a supporting telescopic arm;

[0033] One end of the top support telescopic arm serves as an assembly end, and the other end of the top support telescopic arm serves as a top support output end;

[0034] The assembly end of the top support telescopic arm is assembled and connected with the top support base.

[0035] The top support telescopic arm is provided with an angle adjustment mechanism, and the angle adjustment mechanism is used to drive the top support telescopic arm to swing up and down;

[0036] The support base of the support device is installed on the horizontal support near the bottom of the pit, and the support output end of the support telescopic arm can extend toward the enclosure near the bottom of the pit and apply support prestress to the enclosure near the bottom of the pit;

[0037] S3, using the prestressing system to apply top support prestress to the surrounding area near the bottom of the pit;

[0038] The top support output end of the top support telescopic arm of the top support device is controlled to extend toward the bottom of the enclosure near the pit and apply top support prestress to the bottom of the enclosure near the pit.

[0039] Furthermore, the prestressing system also includes an elevation adjustment device;

[0040] The elevation adjustment device includes a bearing seat and an elevation winch.

[0041] The load-bearing seat is pressed against the bottom of the enclosure near the pit, and the height-adjusting winch is used to drive the load-bearing seat to move up and down against the bottom of the enclosure near the pit;

[0042] The top support output end of the top support telescopic arm applies top support prestress to the surrounding area near the bottom of the pit through a bearing seat;

[0043] Before applying the top support prestress to the position of the enclosure near the bottom of the pit, control the elevation adjustment device to move the bearing seat to the target elevation position for applying the prestress.

[0044] Then, the supporting device is controlled to make the supporting output end of the supporting telescopic arm abut against the supporting support on the bearing seat.

[0045] The top support output end of the top support telescopic arm of the top support device is controlled to apply top support prestress to the surrounding area near the bottom of the pit through a load-bearing seat.

[0046] Furthermore, when applying top support prestress to the enclosure near the bottom of the pit, the deformation condition of the enclosure near the bottom of the pit is detected. According to the deformation condition of the enclosure near the bottom of the pit, the top support device is controlled to apply appropriate top support prestress to the enclosure near the bottom of the pit, so that the deformation condition of the enclosure near the bottom of the pit meets the design standards.

[0047] Furthermore, when installing the prestressing system, first dig the soil near the bottom of the pit of the enclosure to remove the soil near the bottom of the pit of the enclosure.

[0048] Compared with the prior art, the prestressing system and prestressing method of the present invention have the following main beneficial effects:

[0049] After completing the construction of the horizontal support near the pit bottom, immediately start installing the prestressing system based on the horizontal support near the pit bottom, and complete the installation of the prestressing system before the subsequent lower-level excavation operation; the prestressing system can load the top support prestress on the surrounding area near the pit bottom based on the horizontal support near the pit bottom; in this way, the surrounding area near the pit bottom can obtain the loaded top support prestress at the first time, so that the displacement and deformation of the surrounding area near the pit bottom can be controlled in time, thereby improving the overall engineering quality of the foundation pit project. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a structural schematic diagram of a system for applying prestress to enclosures in a foundation pit according to the present invention;

[0051] Figure 2 Based on Figure 1 A top view of the horizontal support near the bottom of the pit. DETAILED DESCRIPTION

[0052] First of all, in order to facilitate a clear and accurate description of the technical solution in the following text, the following definitions are made in advance:

[0053] Definition 1: The "current pit bottom" mentioned in this article refers to the pit bottom during the foundation pit construction excavation process. The "current pit bottom" is a dynamic concept. Wherever the foundation pit is excavated is the "current pit bottom".

[0054] Definition 2: The "designed pit bottom" mentioned in this article refers to the pit bottom designed for foundation pit engineering. The "designed pit bottom" is a static concept.

[0055] Definition 3: The “protection structure near the pit bottom” mentioned in this article refers to the part of the protection structure close to the current pit bottom (such as Figure 1 The “position of the enclosure near the pit bottom” is a dynamic concept, which changes with the current position of the pit bottom. For example, when the “current pit bottom” is excavated to a depth of 1 meter, the position of the enclosure structure near the depth of 1 meter is the “position of the enclosure near the pit bottom”.

[0056] Definition 4: The "horizontal support near the pit bottom" mentioned in this article refers to the horizontal support structure that has been built in the foundation pit and is closest to the current pit bottom. The "horizontal support near the pit bottom" is a dynamic concept. For example, when the first layer of horizontal support structure is completed, the first layer of horizontal support structure is the horizontal support near the pit bottom. When the second layer of horizontal support structure is completed, the second layer of horizontal support structure is the horizontal support near the pit bottom, and the first layer of horizontal support structure is no longer the horizontal support near the pit bottom.

[0057] Definition 5: The "support system" mentioned in this article is a broad concept, which summarizes all forms of "support structures" and their combinations for the retaining structures in the foundation pit, such as "inclined upward support structure" and "horizontal support structure".

[0058] Definition 6: The "lower level foundation pit structure" mentioned in this article refers to the deeper foundation pit structure to be constructed in the next stage of the foundation pit construction process. The "lower level foundation pit structure" is a dynamic concept. For example, there are two layers of horizontal support structures designed in the foundation pit. When the first layer of horizontal support structure is completed, the second layer of horizontal support structure to be constructed is the lower level foundation pit structure. When the second layer of horizontal support structure is completed, the bottom structure of the foundation pit to be constructed is the lower level foundation pit structure.

[0059] Definition 7: The "lower level excavation" mentioned in this article refers to the process of excavation in the foundation pit before the next stage of the construction of the deeper foundation pit structure, so as to open up the construction space for the deeper foundation pit structure. The excavation process during this period is called "lower level excavation". For example, there are two layers of horizontal support structures in the foundation pit. After the construction of the first layer of horizontal support structure is completed, it is necessary to dig downwards to open up the construction space for the second layer of horizontal support structure. The excavation process during this period is called lower level excavation.

[0060] The main idea of ​​the present invention is:

[0061] Based on the horizontal support near the bottom of the pit, an inclined downward support component is set toward the foundation pit retaining structure, and the inclined downward support component is supported at the position of the retaining near the bottom of the pit. Then, a top support force adding mechanism is set for the inclined downward support component, and the top support force adding mechanism can drive the inclined downward support component to apply top support prestress to the position of the retaining near the bottom of the pit.

[0062] The main concept of the present invention is roughly as described above. In this way, the top support prestress can be applied to the bottom of the enclosure near the pit before the lower-level foundation pit structure is completed, so that corresponding measures can be taken in time to deal with the displacement and deformation that may occur near the bottom of the pit, thereby improving the overall engineering quality of the foundation pit project.

[0063] The concept of the present invention is further described below with specific embodiments:

[0064] See also Figure 1 , the foundation pit engineering structure involved in this implementation mode is first introduced below.

[0065] Those skilled in the art can understand that the overall engineering structure of the foundation pit mainly includes the enclosure structure 6 and the enclosure support system, and its specific structure is set as follows:

[0066] The retaining structure 6 is constructed around the foundation pit, and the retaining support system is usually arranged inside the foundation pit to support the retaining structure 6 .

[0067] In this embodiment, the enclosure structure 6 is a pile row enclosure structure.

[0068] The enclosure support system is mainly composed of two layers of horizontal support structures 4.

[0069] The two layers of horizontal support structures 4 are arranged on the inner side of the foundation pit, and the two layers of horizontal support structures 4 support the enclosure structure 6. For each layer of horizontal support structure 4, a corresponding purlin 7 is arranged on the enclosure structure 6. The purlin 7 arranged for the pit top horizontal support structure 4 is at the top of the enclosure structure 6, and the purlin 7 arranged for the pit inside horizontal support structure 4 is arranged on the air side of the enclosure structure 6. The two layers of horizontal support structures 4 are connected to the enclosure structure 6 through the purlin 7, so as to form support for the enclosure structure 6.

[0070] In this embodiment, the enclosure support system also includes a certain number of anti-pull-out devices 5, which are fixed in the foundation pit. Then, the two layers of horizontal support structures 4 mentioned above are connected together with the anti-pull-out devices 5, which provide vertical support for the horizontal support structures 4.

[0071] In addition, in order to conveniently detect the displacement and deformation of the enclosure structure 6 and obtain corresponding data, in this embodiment, an inclinometer tube 8 (existing technology) is pre-buried inside the enclosure structure 6, and an intelligent inclinometer device 81 is configured for the inclinometer tube 8. Through the combination of the inclinometer tube 8 and the intelligent inclinometer device 81, the displacement and deformation related data (inclination) of the enclosure structure 6 can be detected and obtained. For the convenience of description, the combination of the inclinometer tube 8 and the intelligent inclinometer device 81 is called an inclinometer device.

[0072] In addition, an axial force monitoring device 43 is also provided in the horizontal supporting structure 4 , and the axial force monitoring device 43 is used to monitor the horizontal axial force of the horizontal supporting structure 4 , so as to provide data basis for the supporting device 1 to apply supporting prestress.

[0073] Those skilled in the art can understand that the above-mentioned foundation pit engineering structure is a structure of the prior art.

[0074] See also Figure 1 and Figure 2 This embodiment provides a prestressing system, which is set based on the foundation pit engineering structure. The prestressing system is mainly used to apply top support prestress to the enclosure structure 6, especially to apply top support prestress to the enclosure near the bottom of the pit.

[0075] Specifically,

[0076] The prestressing system of this embodiment mainly consists of two parts, namely a supporting device 1 and a height adjusting device.

[0077] In this embodiment, two supporting devices 1 are provided, and both supporting devices 1 are installed based on the horizontal support 41 near the pit bottom.

[0078] As for a single supporting device 1,

[0079] The supporting device 1 mainly includes a supporting base 11 and a supporting telescopic arm 12. The supporting base 11 needs to be assembled on the horizontal supporting structure 4, so its overall configuration matches the horizontal supporting structure 4. In this embodiment, the supporting bases 11 of the two supporting devices 1 are respectively placed on both sides of a support in the horizontal supporting structure 4, and the supporting bases 11 of the two supporting devices 1 are firmly connected together by a pin 112, and the supporting bases 11 of the two supporting devices 1 tightly embrace the support, thereby realizing the fixed installation of the supporting base 11 on the horizontal supporting structure 4.

[0080] In addition, embedded steel components may also be used to achieve connection and assembly between the top support base 11 and the horizontal support structure 4. The specific assembly and connection form between the top support base 11 and the horizontal support structure 4 may be determined according to actual conditions.

[0081] The top support telescopic arm 12 is installed based on the top support base 11 .

[0082] One end of the top support telescopic arm 12 (usually the main body end) serves as the assembly end, and the other end of the top support telescopic arm 12 (usually the telescopic end) serves as the top support output end.

[0083] The assembly end of the top support telescopic arm 12 is assembled and connected to the top support base 11 through an axle pin mechanism, and an angle adjustment mechanism is provided for the top support telescopic arm 12, which is used to drive the top support telescopic arm 12 to swing up and down based on the top support base 11 to adjust the angle of the top support output end of the top support telescopic arm 12 toward the bottom of the enclosure near the pit.

[0084] It should be noted that, in this embodiment, the specific implementation form of the angle adjustment mechanism is as follows:

[0085] A winch is provided for the top support telescopic arm 12, which is called an "angle adjustment winch". The angle adjustment winch 24 is installed on the horizontal support 41 near the bottom of the pit, and the hoisting rope of the angle adjustment winch 24 is connected to the top support output end of the top support telescopic arm 12. In this way, the hoisting and lifting action of the angle adjustment winch 24 can drive the top support telescopic arm 12 to swing up and down.

[0086] It should be noted that the angle-adjusting winch 24 has a rotation counter (commonly known as an encoder), which is helpful for accurately adjusting the swing angle of the top support telescopic arm 12.

[0087] It should be noted that some pulley systems need to be provided for the hoisting rope of the angle-adjusting winch 24 to achieve the steering of the hoisting rope.

[0088] In other embodiments, other structural forms may also be used to implement the angle adjustment mechanism, as long as the function of "driving the top support telescopic arm 12 to swing up and down based on the top support base 11 to adjust the angle of the top support output end of the top support telescopic arm 12 toward the bottom of the enclosure near the pit" can be achieved, and the present invention is not limited to this.

[0089] The supporting output end of the supporting telescopic arm 12 serves as the supporting output end of the entire supporting device 1 and is used to output supporting force to the outside.

[0090] It should be noted that, in the present embodiment, the top support telescopic arm 12 is a two-section hydraulic telescopic rod, which is composed of a large hydraulic loading sleeve combined with a telescopic rod body, which is completely understandable to those skilled in the art.

[0091] In other embodiments, other forms of telescopic arms can be used as long as they can achieve the effect of "being able to telescope and output a strong supporting force to the outside", such as an electric telescopic rod.

[0092] In addition, a top support end head 13 is provided at the top support output end of the top support telescopic arm 12. The top support end head 13 is assembled on the top support output end of the top support telescopic arm 12 through an axle pin mechanism. The top support end head 13 can swing up and down based on the top support output end of the top support telescopic arm 12. The configuration of the top support end head 13 matches the bearing surface 221 of the bearing seat 22 to be mentioned later.

[0093] The elevation adjustment device includes a bearing seat 22, and a winch is configured for the bearing seat 22, and the winch is called a "height adjustment winch".

[0094] The bearing seat 22 is connected to a hoisting rope 231 (steel strand) of a height-adjusting hoist 23, and the height-adjusting hoist 23 is used to hoist and raise the bearing seat 22. When the height-adjusting hoist 23 is arranged on the horizontal support structure 4, the height-adjusting hoist 23 can hoist and raise the bearing seat 22 based on the horizontal support structure 4.

[0095] It should be noted that the height-adjusting winch 23 has a revolution counter (commonly known as an encoder), which is conducive to accurately adjusting the lifting height of the winch.

[0096] The load-bearing seat 22 also has a load-bearing surface, which is used to receive the support of the telescopic arm 12 of the support device 1.

[0097] It should be noted that the height adjustment winch 23 and the angle adjustment winch 24 can be implemented by the same winch. Specifically, two independent winch ropes are arranged on the winch, one of which is connected to the bearing seat 22, and the other is connected to the top support telescopic arm 12. In this way, the winch can adjust the height of the bearing seat 22 and the swing angle of the top support telescopic arm 12, and the adjustment of the two aspects is synchronized, thereby simplifying the equipment configuration and the operation process.

[0098] It should be noted that the prestressing system of this embodiment is mainly used to apply top support prestress to the surrounding area near the bottom of the pit, so the top support device 1 and the elevation adjustment device are mainly installed based on the horizontal support 41 near the bottom of the pit.

[0099] Specifically,

[0100] The supporting base 11 of the supporting device 1 is assembled on the horizontal support 41 near the bottom of the pit, and the supporting telescopic arm 12 of the supporting device 1 can be extended obliquely downward toward the enclosure structure 6, and the supporting output end of the supporting telescopic arm 12 is obliquely downward toward the bottom of the enclosure near the pit.

[0101] The height adjustment winch 23 of the elevation adjustment device is installed on a horizontal support 41 near the pit bottom, and the load-bearing seat 22 of the elevation adjustment device is located below the horizontal support 41 near the pit bottom, with a horizontal support structure 4 between the height adjustment winch 23 and the load-bearing seat 22.

[0102] The load-bearing seat 22 is pressed against the bottom of the enclosure near the pit, and the height-adjusting winch 23 can drive the load-bearing seat 22 to move up and down against the bottom of the enclosure near the pit.

[0103] It should be noted that the hoisting rope 231 of the height-adjusting winch 23 needs to pass through the horizontal support 41 near the bottom of the pit before it can be connected to the force-bearing seat 22. Therefore, a penetration pipe 29 is provided at the corresponding position of the enclosure near the bottom of the pit. The hoisting rope 231 of the height-adjusting winch 23 can be connected to the force-bearing seat 22 after passing through the penetration pipe 29, and drive the force-bearing seat 22 to move up and down.

[0104] It should be noted that some pulley systems need to be set for the hoisting rope 231 of the height-adjusting winch 23 to realize the steering of the hoisting rope 231, so as to realize the "up and down lifting and lowering movement of the load-bearing seat 22 against the bottom of the enclosure", which is clearly known to those skilled in the art, so it will not be elaborated in detail.

[0105] It should be noted that, in other embodiments, the height-adjusting winch 23 does not have to be installed on the horizontal support 41 near the pit bottom, but can also be installed at other parts of the foundation pit structure, as long as it can achieve "the height-adjusting winch 23 can drive the load-bearing seat 22 to move up and down against the surrounding area near the pit bottom".

[0106] The elevation adjustment device is used to set a bearing seat 22 at the supporting position of the enclosure near the bottom of the pit, and the supporting force applied by the supporting device 1 acts on the enclosure structure 6 through the bearing seat 22.

[0107] Since the enclosure structure 6 involved in this embodiment is a pile row enclosure structure, the applied supporting force acts on the pile row enclosure structure through the bearing seat 22, so that the entire pile row enclosure structure can be evenly stressed.

[0108] When it is necessary to apply top support prestress to the prestress application target elevation position determined on the enclosure near the bottom of the pit, the winch 23 is raised to drive the load-bearing seat 22 to move to the determined prestress application target elevation position, and then the top support output end of the top support telescopic arm 12 of the top support device 1 is controlled to extend and support on the load-bearing seat 22. The top support force applied by the top support device 1 is transmitted to the enclosure near the bottom of the pit through the load-bearing seat 22, thereby realizing the application of top support prestress.

[0109] In addition, the bearing seat 22 also has a bearing surface 221. When the bearing seat 22 is against the bottom of the enclosure near the pit, the bearing surface 221 of the bearing seat 22 faces the direction where the supporting device 1 is located. The bearing surface 221 is used to receive the top pressure of the supporting output end (supporting end 13) of the supporting telescopic arm 12 of the supporting device 1. The supporting force applied by the supporting device 1 can be transmitted to the bottom of the enclosure near the pit through the bearing seat 22. The bearing surface 221 is slightly inclined upward, or in other words, the bearing surface 221 is slightly inclined toward the supporting base 11 of the supporting device 1, so as to receive the top pressure of the supporting telescopic arm 12 of the supporting device 1 as directly as possible.

[0110] It should be noted that the configuration of the bearing surface 221 of the bearing seat 22 matches the configuration of the previously mentioned supporting end 13. In this way, when the supporting output end of the supporting telescopic arm 12 is pressed against the bearing surface 221 of the bearing seat 22, the supporting end 13 can fit together with the bearing surface 221 of the bearing seat 22, and the friction force between the two will be very large, so that the supporting output end of the supporting telescopic arm 12 can be firmly supported on the bearing seat 22.

[0111] The prestressing system of this embodiment also includes a prestressing control computer. The electrical equipment such as the jacking device 1 and the elevation adjustment device are all controlled by the prestressing control computer, and the inclinometer and the axial force monitoring device 43 are also connected to the prestressing control computer signal. In this way, the prestressing control computer can control the jacking device 1 and the elevation adjustment device, etc. to apply jacking prestress to the enclosure near the bottom of the pit according to the detection data of the inclinometer and the axial force monitoring device 43. Moreover, a control program for applying jacking prestress is provided in the prestressing control computer, thereby realizing the intelligent control of "controlling the jacking device 1 and the elevation adjustment device to apply jacking prestress to the enclosure near the bottom of the pit according to the detection data of the inclinometer and the axial force monitoring device 43".

[0112] This embodiment also provides a method for applying prestress to the enclosure in the foundation pit, and the prestressing method is used to achieve "applying top support prestress to the enclosure near the bottom of the pit". In essence, the prestressing method is achieved by adopting the concept of applying prestressing system mentioned above.

[0113] Specifically, the method for applying prestress in this embodiment includes:

[0114] S1, construct a horizontal support 41 near the bottom of the foundation pit at the construction location of the foundation pit.

[0115] It should be noted that the horizontal support 41 near the pit bottom is constructed based on the anti-pullout device 5 pre-constructed in the foundation pit.

[0116] The constructed horizontal support 41 near the pit bottom is as described above and will not be repeated here.

[0117] S2, after completing the construction of the horizontal support 41 near the pit bottom in step S1, immediately install the prestressing system based on the horizontal support 41 near the pit bottom, and complete the installation of the prestressing system before the subsequent lower level excavation operation.

[0118] The specific installation structure of the prestressing system is as described above and will not be repeated here.

[0119] It should be noted that when installing the prestressed system, it is necessary to first dig the soil near the bottom of the enclosure near the pit and remove the soil near the bottom of the enclosure near the pit. The purpose of this is to provide operating space for "the elevation adjustment device to move the load-bearing seat 22 downward to the bottom of the enclosure near the pit, and the top support telescopic arm 12 of the top support device 1 to swing downward toward the load-bearing surface of the load-bearing seat 22, and then make the top support output end of the top support telescopic arm 12 rest against the top support on the load-bearing surface of the load-bearing seat 22."

[0120] It should be noted that the "digging at the bottom of the pit near the enclosure" here does not fall into the category of "lower level digging operations".

[0121] S3, use the prestressing system to apply top support prestress to the surrounding area near the bottom of the pit.

[0122] Specifically,

[0123] Determine the target elevation position of prestressing near the bottom of the pit;

[0124] Control the elevation adjustment device to move the bearing seat 22 to the target elevation position for prestressing;

[0125] The telescopic arm 12 of the jacking support device 1 is controlled to extend obliquely downward toward the bottom of the enclosure near the pit, especially to make the jacking output end of the telescopic arm 12 face the load-bearing seat 22 at the target elevation position of prestressing, and the jacking support device 1 is controlled to make the jacking end 13 on the jacking output end of the telescopic arm 12 abut against the load-bearing surface 221 of the load-bearing seat 22. The jacking force applied by the telescopic arm 12 of the jacking support device 1 acts on the target elevation position of prestressing at the bottom of the enclosure near the pit through the load-bearing seat 22.

[0126] The previously mentioned inclinometer is used to detect the deformation condition (deformation data) of the enclosure near the bottom of the pit. According to the deformation condition of the enclosure near the bottom of the pit and in accordance with the design standards, the top support device 1 is controlled to apply appropriate top support prestress to the enclosure near the bottom of the pit so that the deformation condition of the enclosure near the bottom of the pit meets the design standards.

[0127] At this point, the prestressing method of this embodiment achieves the effect of "precisely applying top support prestress at the target elevation position of prestressing near the bottom of the pit".

[0128] It should be noted that for the entire control process of step S3, a pre-designed software control program is provided in the prestress control computer. The entire control process of step S3 is actually controlled and implemented by the prestress control computer according to the pre-designed software control program.

[0129] After the prestressing method is implemented, the lower level excavation operation can begin.

[0130] It should be noted that, in this embodiment, the supporting device 1 is assembled at the position where the horizontal supporting structure 4 is connected to the anti-pullout device 5, and the supporting base 11 of the supporting device 1 can be assembled and connected with the anti-pullout device 5 through a pin or a pre-embedded steel member. In this way, the supporting device 1 can obtain strong vertical support when applying the supporting prestress, and the horizontal supporting structure 4 will not be deformed due to the reaction force caused by the supporting prestress applied by the supporting device 1.

[0131] It should be noted that in other embodiments, the elevation adjustment device is not necessary. In other embodiments, if the enclosure structure 6 is a continuous wall enclosure structure, the elevation adjustment device may not be provided, and the top support output end of the top support telescopic arm 12 of the top support device 1 may directly rest against the enclosure structure 6.

[0132] It should be noted that the bearing seat 22 can be a concrete component or a prefabricated steel component.

[0133] It should be noted that the prestressing system can be applied to the entire enclosure structure or to a partial enclosure structure.

[0134] It should be noted that the prestressing system and prestressing method of this embodiment are not only implemented for one layer of horizontal support structure 4, but can also be implemented for multiple layers of horizontal support structure 4.

[0135] The main advantages of the prestressing system and prestressing method of this embodiment are:

[0136] 1) After the construction of the horizontal support 41 near the pit bottom is completed, the prestressing system is immediately installed based on the horizontal support 41 near the pit bottom, and the installation of the prestressing system is completed before the subsequent lower level excavation operation;

[0137] The supporting device 1 in the prestressing system has a supporting telescopic arm 12, the supporting output end of which can extend obliquely downward toward the bottom of the enclosure near the pit and apply supporting prestress to the bottom of the enclosure near the pit;

[0138] In this way, the top support prestress can be applied to the part of the retaining wall near the bottom of the pit in the first place, so that the displacement and deformation of the part of the retaining wall near the bottom of the pit can be corrected in time, thereby improving the overall engineering quality of the foundation pit project.

[0139] In addition, the prestressing system and prestressing method of this embodiment also have the following advantages:

[0140] 2) No embedded parts are required in the early stage, it can be installed at any time, the installation is flexible, and no special structural settings are required;

[0141] 3) The prestressing system can intelligently determine the target elevation position of prestressing on the bottom of the pit of the enclosure according to the inclination data of the inclinometer, so that the strength and direction of the prestressing applied by the supporting device 1 can be more accurately controlled during the construction process;

[0142] 4) The prestressing system and prestressing method can effectively apply top support prestressing to the part of the enclosure near the bottom of the pit, thereby effectively controlling the deformation of the part of the enclosure near the bottom of the pit and improving the safety and reliability of foundation pit construction.

[0143] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for applying prestress to the enclosure in a foundation pit, characterized in that: The prestressing system comprises a supporting device (1); The supporting device (1) comprises a supporting base (11) and a supporting telescopic arm (12); One end of the top support telescopic arm (12) serves as an assembly end, and the other end of the top support telescopic arm (12) serves as a top support output end; The assembly end of the top support telescopic arm (12) is assembled and connected to the top support base (11). The top support telescopic arm (12) is provided with an angle adjustment mechanism, and the angle adjustment mechanism is used to drive the top support telescopic arm (12) to swing up and down; The supporting base (11) of the supporting device (1) is mounted on a horizontal support (41) near the bottom of the pit, and the supporting output end of the supporting telescopic arm (12) can extend toward the surrounding area near the bottom of the pit and apply supporting prestress to the surrounding area near the bottom of the pit.

2. The prestressing system for the enclosure in the foundation pit according to claim 1 is characterized in that: The prestressing system also includes a height adjustment device; The elevation adjustment device comprises a bearing seat (22) and an elevation adjustment winch (23). The load-bearing seat (22) is pressed against the bottom of the enclosure near the pit, and the height-adjusting winch (23) is used to drive the load-bearing seat (22) to move up and down against the bottom of the enclosure near the pit; The top support output end of the top support telescopic arm (12) applies top support prestress to the surrounding area near the bottom of the pit through a bearing seat (22).

3. The prestressing system for the enclosure in the foundation pit according to claim 2 is characterized in that: The height-adjusting winch (23) is installed on a horizontal support (41) near the pit bottom.

4. The prestressing system for the enclosure in the foundation pit according to claim 2 is characterized in that: The load-bearing seat (22) has a load-bearing surface (221), and the load-bearing surface (221) of the load-bearing seat (22) is inclined upward and faces the supporting base (11) of the supporting device (1).

5. The prestressing system for the enclosure in the foundation pit according to claim 4 is characterized in that: A supporting end head (13) is arranged on the supporting output end of the supporting telescopic arm (12), and the supporting end head (13) is assembled on the supporting output end of the supporting telescopic arm (12) through a shaft pin mechanism.

6. The prestressing system for enclosure in the foundation pit according to claim 2 is characterized in that: An inclinometer is provided for the enclosure structure (6), and an axial force monitoring device (43) is provided for the horizontal support (41) near the bottom of the pit; The prestressing system also includes a prestressing control computer, the supporting device (1) and the elevation adjustment device are both controlled by the prestressing control computer, and the inclination measuring device and the axial force monitoring device (43) are connected to the prestressing control computer by signals; The prestress control computer can control the top support device (1) and the elevation adjustment device to apply top support prestress to the surrounding area near the bottom of the pit according to the detection data of the inclinometer and the axial force monitoring device (43).

7. The prestressing system for the enclosure in the foundation pit according to claim 1 is characterized in that: The top support base (11) is assembled and arranged at the connection between the horizontal support (41) near the bottom of the pit and the anti-pullout device (5).

8. The prestressing system for enclosure in the foundation pit according to claim 1 is characterized by: The number of the supporting devices (1) is two, and the supporting bases (11) of the two supporting devices (1) are respectively placed on both sides of the horizontal support (41) near the pit bottom, and the supporting bases (11) of the two supporting devices (1) are connected together by fasteners, and the supporting bases (11) of the two supporting devices (1) embrace the horizontal support (41) near the pit bottom, thereby realizing the installation of the supporting base (11) on the horizontal support (41) near the pit bottom.

9. The prestressing system for enclosure in the foundation pit according to claim 2 is characterized by: The angle adjustment mechanism is specifically implemented in the form of an angle adjustment winch (24) configured for the top support telescopic arm (12), the angle adjustment winch (24) being installed on a horizontal support (41) near the bottom of the pit, the hoisting rope of the angle adjustment winch (24) being connected to the top support output end of the top support telescopic arm (12), and the hoisting and lifting action of the angle adjustment winch (24) can drive the top support telescopic arm (12) to swing up and down.

10. The prestressing system for enclosure in the foundation pit according to claim 9 is characterized in that: The angle adjustment winch (24) and the height adjustment winch (23) are the same winch.

11. A method for applying prestress to enclosure in a foundation pit, characterized in that: The method for applying prestress comprises: S1, constructing a horizontal support near the bottom of the pit (41); S2, installing a prestressing system based on the horizontal support (41) near the bottom of the pit, and completing the installation of the prestressing system before the subsequent lower level excavation operation; The prestressing system comprises a supporting device (1); The supporting device (1) comprises a supporting base (11) and a supporting telescopic arm (12); One end of the top support telescopic arm (12) serves as an assembly end, and the other end of the top support telescopic arm (12) serves as a top support output end; The assembly end of the top support telescopic arm (12) is assembled and connected to the top support base (11). The top support telescopic arm (12) is provided with an angle adjustment mechanism, and the angle adjustment mechanism is used to drive the top support telescopic arm (12) to swing up and down; The supporting base (11) of the supporting device (1) is mounted on a horizontal support (41) near the bottom of the pit, and the supporting output end of the supporting telescopic arm (12) can extend toward the bottom of the enclosure near the pit and apply supporting prestress to the bottom of the enclosure near the pit; S3, using the prestressing system to apply top support prestress to the surrounding area near the bottom of the pit; The supporting output end of the supporting telescopic arm (12) of the supporting device (1) is controlled to extend toward the bottom of the enclosure near the pit and apply supporting prestress to the bottom of the enclosure near the pit.

12. The method for applying prestress to the enclosure in the foundation pit according to claim 11, characterized in that: The prestressing system also includes a height adjustment device; The elevation adjustment device comprises a bearing seat (22) and an elevation adjustment winch (23). The load-bearing seat (22) is pressed against the bottom of the enclosure near the pit, and the height-adjusting winch (23) is used to drive the load-bearing seat (22) to move up and down against the bottom of the enclosure near the pit; The top support output end of the top support telescopic arm (12) applies top support prestress to the surrounding area near the bottom of the pit through a bearing seat (22); Before applying the top support prestress to the position of the enclosure near the pit bottom, the elevation adjustment device is controlled to move the bearing seat (22) to the target elevation position for applying the prestress. Then, the supporting device (1) is controlled so that the supporting output end of the supporting telescopic arm (12) abuts against the supporting support on the bearing seat (22). The supporting output end of the supporting telescopic arm (12) of the supporting device (1) is controlled to apply supporting prestress to the surrounding area near the bottom of the pit through a bearing seat (22).

13. The method for applying prestress to the enclosure in the foundation pit according to claim 11, characterized in that: When applying top support prestress to the part of the enclosure near the pit bottom, the deformation condition of the part of the enclosure near the pit bottom is detected, and according to the deformation condition of the part of the enclosure near the pit bottom, the top support device (1) is controlled to apply appropriate top support prestress to the part of the enclosure near the pit bottom, so that the deformation condition of the part of the enclosure near the pit bottom meets the design standard.

14. The method for applying prestress to the enclosure in the foundation pit according to claim 11, characterized in that: When installing the prestressing system, first dig the soil near the bottom of the pit of the enclosure and remove the soil near the bottom of the pit of the enclosure.

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