Foundation pit support displacement deformation advanced control system and method

Abstract

The invention discloses an advanced control system and method for displacement deformation of a foundation pit support. According to the control system and the control method, the control system is constructed before subsequent digging operation of a lower layer, and the control system comprises a lower inclined strut pile (3) and a grouting bag (21); a back shore stress application mechanism (11) is arranged at the stress application end of the lower diagonal bracing pile on the diagonal bracing foundation part based on a horizontal support (16) close to the pit bottom, and the back shore stress application mechanism applies thrust to the lower diagonal bracing pile based on the horizontal support close to the pit bottom, so that the back shore end of the lower diagonal bracing pile applies back shore prestress to the part close to the pit bottom of the enclosure; the grouting bag is arranged on the periphery of the enclosure structure (5), and a grouting background (24) is arranged for the grouting bag. According to the control system and the control method, the measure of applying the back shore prestress can be taken at the first time when displacement deformation possibly happens to the portion, close to the pit bottom, of the enclosure, deformation of the portion, close to the pit bottom, of the enclosure is prevented, and the deformation condition in the excavation process of the foundation pit is effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit engineering, and in particular to a foundation pit enclosure displacement deformation advance control system and method. Background Art

[0002] With the acceleration of urbanization, the development and utilization of urban underground space has become an effective way to alleviate urban pressure and enhance the comprehensive carrying capacity of cities. In this context, deep foundation pit excavation technology has been widely used. However, deep foundation pit excavation will have a certain impact on the surrounding environment, and may cause settlement and displacement of surrounding strata, thereby affecting the safety of adjacent subway tunnels, buildings, etc. In order to solve this problem, the prior art proposes a solution of using a concrete support force device. Its main technical concept is to "use a force device to apply a lateral thrust to the retaining structure outside the foundation pit to achieve active control of the displacement of the retaining structure (see the Chinese patent "A support system for actively controlling foundation pit displacement and its design method-CN108130910A").

[0003] The current problem is:

[0004] 1) The active control of the displacement of the retaining structure currently implemented can only apply transverse top support prestressing to the excavation surface of the retaining structure, but cannot apply top support prestressing to the bottom of the retaining near the pit in advance, especially before the construction of the lower level foundation pit structure is completed. In this way, the bottom of the retaining near the pit may produce displacement deformation before the construction of the lower level foundation pit structure is completed, and the deformation of the foundation pit cannot be effectively controlled;

[0005] 2) If the soil rheology around the foundation pit project is serious, the displacement and deformation of the surrounding structure will be aggravated;

[0006] 3) The existing technology lacks intelligent control of foundation pit deformation by combining monitoring data. Summary of the invention

[0007] The purpose of the present invention is to provide an advance control system and method for displacement and deformation of foundation pit retaining walls. The lower inclined support piles arranged in the control system can apply top support prestress to the retaining wall near the bottom of the pit based on the horizontal support near the bottom of the pit. The grouting bags arranged on the periphery of the retaining structure protect the retaining structure. At the first time when displacement and deformation may occur at the retaining wall near the bottom of the pit, measures for applying top support prestress can be taken to prevent displacement and deformation of the retaining wall near the bottom of the pit in time.

[0008] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0009] A foundation pit retaining displacement deformation advance control system, the control system comprising lower inclined support piles;

[0010] One end of the lower oblique support pile serves as the top support end, and the other end of the lower oblique support pile serves as the force-applying end;

[0011] The force-adding end of the lower oblique support pile is based on the horizontal support near the bottom of the pit, and the top support end of the lower oblique support pile is supported obliquely downward on the position of the enclosure near the bottom of the pit;

[0012] A top support force-adding mechanism is provided at the base of the diagonal support, and the top support force-adding mechanism can apply thrust to the lower diagonal support pile based on the horizontal support near the bottom of the pit, so that the top support end of the lower diagonal support pile applies top support prestress to the position of the enclosure near the bottom of the pit;

[0013] The diagonal brace foundation is the part near the bottom of the pit where the upper and lower diagonal brace piles are supported horizontally;

[0014] The control system also includes a grouting bag; the grouting bag is arranged on the periphery of the enclosure structure, and a grouting backstage is configured for the grouting bag.

[0015] Furthermore, an inclinometer is provided inside the enclosure structure, an axial force monitoring device is provided on the horizontal support near the bottom of the pit, and an intelligent column inclinometer is provided on the pull-out pile;

[0016] The control system also includes an intelligent control system background; the inclination measuring device, axial force monitoring device and intelligent column inclination measuring monitoring are all connected to the intelligent control system background data signal, and the grouting background and top support force mechanism are controlled by the intelligent control system background;

[0017] The intelligent control system background can dynamically control the detection data of the inclinometer, the axial force monitoring device and the intelligent column inclinometer monitoring.

[0018] The top support force-adding mechanism drives the lower inclined support pile to apply top support prestress to the surrounding area near the bottom of the pit.

[0019] as well as,

[0020] The grouting background is used to carry out the grouting process on the grouting bag.

[0021] Furthermore, the control system also includes a water-stop steel plate;

[0022] The position where the lower inclined support pile applies top support prestress to the surrounding area near the bottom of the pit is below the bottom of the pit;

[0023] The water-stop steel plate is arranged at the intersection of the lower diagonal support pile and the bottom surface of the pit, and is cast together with the bottom plate.

[0024] Furthermore, the control system also includes upper diagonal support piles, which support the diagonal support base based on the upper part of the near-bottom support.

[0025] Furthermore, a device assembly interval is left between the edge of the horizontal support near the pit bottom and the surrounding structure;

[0026] The control system also includes a transverse supporting telescopic cylinder, which is arranged at the assembly interval of the device. The transverse supporting telescopic cylinder applies transverse supporting prestress to the enclosure structure based on the edge of the horizontal support near the bottom of the pit.

[0027] Furthermore, the control system also includes a rope lifting device, which is mounted on a horizontal support near the bottom of the pit, and the rope of the rope lifting device is connected to the top support end of the lower oblique support pile;

[0028] The rope lifting device is used to adjust the upper and lower positions of the top support end of the lower diagonal support pile at the position of the enclosure near the bottom of the pit.

[0029] Furthermore, the control system includes a base purlin; a lower oblique support base purlin is arranged at the end of the oblique downward prestressed top support structure; and the lower oblique support base purlin is constructed together with the support.

[0030] A method for controlling displacement and deformation of foundation pit support in advance, the control method comprising:

[0031] S1, construct horizontal support near the bottom of the pit;

[0032] S2, construct an advance control system for displacement and deformation of foundation pit support, and complete the construction of the control system before the subsequent lower level excavation operation;

[0033] The constructed control system includes lower diagonal support piles;

[0034] One end of the lower oblique support pile serves as the top support end, and the other end of the lower oblique support pile serves as the force-applying end;

[0035] The force-adding end of the lower oblique support pile is based on the horizontal support near the bottom of the pit, and the top support end of the lower oblique support pile is supported obliquely downward on the position of the enclosure near the bottom of the pit;

[0036] A top support force-adding mechanism is provided at the base of the diagonal support, and the top support force-adding mechanism can apply thrust to the lower diagonal support pile based on the horizontal support near the bottom of the pit, so that the top support end of the lower diagonal support pile applies top support prestress to the position of the enclosure near the bottom of the pit;

[0037] The diagonal brace foundation is the part near the bottom of the pit where the upper and lower diagonal brace piles are supported horizontally;

[0038] The control system also includes a grouting bag; the grouting bag is arranged on the periphery of the enclosure structure, and a grouting backstage is configured for the grouting bag;

[0039] S3, using the control system to apply top support prestress to the horizontal support near the bottom of the pit;

[0040] Grouting is carried out in sections into the grouting bags according to the displacement and deformation conditions of the retaining structure.

[0041] Furthermore, an inclinometer is provided inside the enclosure structure, an axial force monitoring device is provided on the horizontal support near the bottom of the pit, and an intelligent column inclinometer is provided on the pull-out pile;

[0042] The constructed control system also includes an intelligent control system background; the inclination measuring device, axial force monitoring device and intelligent column inclination measuring monitoring are all connected with the intelligent control system background data signal, and the grouting background and top support force mechanism are controlled by the intelligent control system background;

[0043] The intelligent control system background is used to dynamically control the detection data of the inclinometer, the axial force monitoring device and the intelligent column inclinometer monitoring.

[0044] The top support force-adding mechanism drives the lower inclined support pile to apply top support prestress to the surrounding area near the bottom of the pit.

[0045] as well as,

[0046] The grouting background is used to carry out the grouting process on the grouting bag.

[0047] Furthermore, the constructed control system also includes a water-stop steel plate;

[0048] The position where the lower inclined support pile applies top support prestress to the surrounding area near the bottom of the pit is below the bottom of the pit;

[0049] The water-stop steel plate is arranged at the intersection of the lower diagonal support pile and the bottom surface of the pit, and is cast together with the bottom plate.

[0050] Furthermore, the constructed control system also includes upper diagonal support piles, which support the diagonal support base based on the upper part of the near-bottom support.

[0051] Furthermore, a device assembly interval is left between the edge of the constructed horizontal support near the pit bottom and the surrounding structure;

[0052] The constructed control system also includes a transverse top support telescopic cylinder, which is arranged at the device assembly interval. The transverse top support telescopic cylinder applies transverse top support prestress to the retaining structure based on the edge of the horizontal support near the pit bottom.

[0053] Furthermore, the constructed control system also includes a rope lifting device, which is mounted on a horizontal support near the bottom of the pit, and the rope of the rope lifting device is connected to the top support end of the lower oblique support pile;

[0054] In the process of constructing the control system, the rope lifting device is used to adjust the upper and lower positions of the top support end of the lower diagonal support pile at the position of the enclosure near the bottom of the pit.

[0055] Furthermore, the top supporting end of the lower oblique supporting pile and the top supporting retaining structure are located in the soil below the current bottom of the foundation pit.

[0056] Compared with the prior art, the control system of the present invention has the following main beneficial effects:

[0057] 1) Before the subsequent lower-level excavation operation, an advance control system for displacement and deformation of the foundation pit support is constructed. The lower inclined support piles in the control system can apply top support prestressing to the bottom of the support near the pit based on the horizontal support near the bottom of the pit. Thus, the top support prestressing measures can be taken at the first time when the displacement and deformation of the bottom of the support near the pit may occur, so as to prevent the displacement and deformation of the bottom of the support near the pit in time, thereby effectively controlling the deformation problem during the excavation of the foundation pit engineering;

[0058] 2) The grouting bags of the control system are arranged on the periphery of the retaining structure, thereby protecting the retaining structure from the periphery, which can prevent the serious rheological changes of the soil around the foundation pit project and aggravate the displacement and deformation of the retaining structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Schematic diagram of the prestressed top support structure inclined downward in the foundation pit according to implementation mode 1;

[0060] Figure 2 Schematic diagram of the connection between the lower diagonal support pile and the retaining structure using bonding slurry in implementation mode 1;

[0061] Figure 3 It is a schematic diagram of the connection between the lower inclined support pile and the surrounding structure using the claw-tooth gripping method;

[0062] Figure 4 It is a structural schematic diagram of the top support force-adding mechanism used in implementation mode 1;

[0063] Figure 5 It is a schematic diagram of the foundation pit retaining wall displacement deformation advance control system based on embodiment 2 of the present invention. DETAILED DESCRIPTION

[0064] 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:

[0065] 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".

[0066] 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.

[0067] Definition 3: 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.

[0068] Definition 4: The "position of the enclosure near the pit bottom" mentioned in this article refers to the position of the enclosure structure close to the current pit bottom, more precisely, the position from the "horizontal support near the pit bottom" to the "current pit bottom" and a certain distance below the "current pit bottom". The "position of the enclosure near the pit bottom" is a dynamic concept, which changes with the position of the current pit bottom.

[0069] Definition 5: The "upper part of the retaining structure's support near the pit bottom" mentioned in this article refers to the part of the retaining structure that is adjacent to the horizontal support near the pit bottom and is located above the horizontal support near the pit bottom.

[0070] Definition 6: 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".

[0071] Definition 7: 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.

[0072] Definition 8: 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 a deeper foundation pit structure, so as to open up a 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 structures is completed, it is necessary to excavate downwards to open up a construction space for the second layer of horizontal support structures. The excavation process during this period is called lower level excavation.

[0073] It should be noted that the foundation pit enclosure displacement deformation advance control system and method of the present invention is improved based on a prestressed top support structure inclined downward in a foundation pit and a method for applying prestress to the top support. The following first introduces the prestressed top support structure inclined downward in a foundation pit and the method for applying prestress to the top support.

[0074] The main concept of the inclined downward prestressed top support structure in the foundation pit and the method of applying the top support prestress is:

[0075] Based on the horizontal support near the pit bottom, a downward slanting support component is arranged toward the foundation pit retaining structure, and the downward slanting support component is supported at a position near the pit bottom of the retaining structure of the foundation pit.

[0076] Then, a top support force-adding mechanism is configured for the oblique downward support component, and the top support force-adding mechanism is set on the horizontal support near the bottom of the pit. The top support force-adding mechanism can apply thrust to the oblique downward support component based on the horizontal support near the bottom of the pit, so as to push the oblique downward support component to apply top support prestress to the surrounding area near the bottom of the pit.

[0077] In this way, it is not necessary to complete the construction of the lower level foundation pit structure, and the top support prestressing can be applied to the position of the retaining wall near the bottom of the pit, so that active response measures can be taken in time to the displacement and deformation of the retaining wall near the bottom of the pit, without having to wait until the lower level foundation pit structure is completed before taking measures.

[0078] The main concept of the oblique downward prestressed top support structure in the foundation pit and the method for applying top support prestress is roughly as described above. The oblique downward prestressed top support structure in the foundation pit and the method for applying top support prestress are specifically introduced below through a specific implementation method (implementation method 1).

[0079] Implementation 1:

[0080] See also Figure 1 , the foundation pit engineering structure involved in implementation mode 1 is first introduced below.

[0081] Those skilled in the art can understand that the overall engineering structure of the foundation pit mainly includes the enclosure structure 5 and the enclosure support system, and its specific structure is set as follows:

[0082] The retaining structure 5 is constructed around the foundation pit, and the retaining support system is usually arranged inside the foundation pit to support the retaining structure 5 .

[0083] In this embodiment 1, the enclosure support system is mainly composed of several layers of horizontal support structures 1. The several layers of horizontal support structures 1 are arranged on the inner side of the foundation pit, and the enclosure structure 5 is supported by these horizontal support structures 1. For each layer of horizontal support structure 1, a corresponding purlin 2 is arranged on the enclosure structure 5, and each layer of horizontal support structure 1 is connected to the enclosure structure 5 through the purlin 2, thereby forming support for the enclosure structure 5.

[0084] In this embodiment 1, the retaining support system also includes a certain number of pull-out piles 6, which are fixed in the foundation pit by pull-out devices 8 arranged at the bottom of the foundation pit. Then, the several layers of horizontal support structures 1 mentioned above are connected together with the pull-out piles 6, and these pull-out piles 6 provide vertical support for the horizontal support structure 1.

[0085] In addition, in order to conveniently detect the displacement and deformation of the enclosure structure 5 and obtain corresponding data, in this embodiment, an inclinometer 19 (existing technology) is pre-buried inside the enclosure structure 5, and the inclinometer 19 can detect and obtain the displacement and deformation related data of the enclosure structure 5.

[0086] See also Figures 1 to 4 Implementation 1 provides a prestressed support structure inclined downward in a foundation pit. The prestressed support structure is arranged based on the foundation pit engineering structure described above. The prestressed support structure is used to apply prestressed support to the part of the enclosure near the bottom of the pit, thereby preventing the enclosure near the bottom of the pit from displacement and deformation at the first time.

[0087] See also Figure 1 The oblique downward prestressed top support structure mainly includes a large number of lower oblique support piles 3, and the lower oblique support piles 3 are equivalent to the oblique downward support components.

[0088] For the convenience of description, one end of the lower oblique support pile 3 is called the top support end, and the other end of the lower oblique support pile 3 is called the force application end.

[0089] The force-adding ends of these lower inclined support piles 3 are arranged based on the horizontal support 16 near the bottom of the pit, and the top supporting ends of the lower inclined support piles 3 are supported obliquely downward on the bottom of the retaining structure 5 to prevent the bottom of the retaining structure from being displaced and deformed toward the inside of the foundation pit.

[0090] It should be noted that, for the convenience of description, the "part on which the force-applying ends of the upper and lower diagonal bracing piles 3 of the horizontal support 16 near the pit bottom are based" is referred to as the "diagonal bracing base part".

[0091] It should be noted that the top support end of the finally constructed lower inclined support pile 3 is in the soil, that is, the top support of the surrounding structure near the bottom of the pit is in the soil below the current bottom of the foundation pit. Therefore, before the subsequent lower level excavation operation, the part of the surrounding structure 5 still in the soil can be supported to achieve advanced top support prestressing intervention.

[0092] For each lower inclined support pile 3, a top support force-adding mechanism 11 is provided at the position of the lower inclined support pile 3 based on the horizontal support 16 near the pit bottom. The top support force-adding mechanism 11 can apply thrust to the lower inclined support pile 3 based on the horizontal support 16 near the pit bottom, so that the top support end of the lower inclined support pile 3 actively applies top support prestress to the retaining structure 5 near the pit bottom, thereby actively suppressing the displacement deformation of the retaining structure near the pit bottom toward the inside of the foundation pit.

[0093] More specifically,

[0094] See also Figure 4 The specific structure of the top support force adding mechanism 11 is implemented as follows:

[0095] The supporting force adding mechanism 11 mainly includes a reaction bracket 9 , a first jack 110 and a reaction frame 116 .

[0096] The reaction bracket 9 is installed on the horizontal support 16 near the bottom of the pit.

[0097] It should be noted that the reaction bracket 9 is a component of the prior art, and a through hole is opened inside the bracket as a bracket hole, and the bracket hole is used to pass through the lower diagonal support pile 3. The reaction bracket 9 also has a reaction surface (such as Figure 4 (indicated by arrow B in the figure).

[0098] The reaction frame 116 has a configuration similar to that of a door frame, and has a reaction beam 115. The reaction frame 116 is fixed to the reaction bracket 9, specifically to the reaction surface of the reaction bracket 9, through fixing parts such as anchor bolts 111 and anchor steel plates 112. In this way, the reaction beam 115 of the reaction frame 116 faces the force-applying end of the lower diagonal support pile 3 (the lower diagonal support pile is not shown in the figure).

[0099] A certain spacing is left between the reaction beam 115 and the reaction bracket 9 as a jack retention space, and the first jack 110 is placed in the jack retention space and is arranged between the "reaction beam 115 of the reaction frame 116" and the "force-applying end of the lower diagonal support pile 3". In this way, the first jack 110 can apply a thrust to the force-applying end of the lower diagonal support pile 3 based on the reaction beam 115 of the reaction frame 116, or in other words, the top support force-applying mechanism 11 can apply a thrust to the force-applying end of the lower diagonal support pile 3 based on the horizontal support 16 near the bottom of the pit, so that the top support end of the lower diagonal support pile 3 can apply a top support prestress to the surrounding near the bottom of the pit.

[0100] See also Figure 2 The top support end of the lower inclined support pile 3 is fixedly connected to the surrounding area near the bottom of the pit by bonding slurry (such as Figure 2 In this way, when the top support force mechanism 11 applies a thrust to the lower oblique support pile 3, the top support end of the lower oblique support pile 3 forms a top support effect on the surrounding area near the bottom of the pit.

[0101] More specifically,

[0102] Four grouting passages (not shown in the figure) are arranged inside the lower diagonal support pile 3 , and the openings at both ends of the grouting passages are respectively located at the two ends (force application end and top support end) of the lower diagonal support pile 3 .

[0103] When constructing a downward inclined prestressed top support structure, when it is necessary to connect the top support end of the lower inclined support pile 3 with the part of the enclosure near the bottom of the pit, first place the top support end of the lower inclined support pile 3 against the enclosure structure 5, and then, through the grouting passage, pour the pre-prepared bonding slurry from the force-applying end of the lower inclined support pile 3 to the top support end, that is, the part between the top support end of the lower inclined support pile 3 and the part of the enclosure near the bottom of the pit, and after the bonding slurry solidifies, the two are connected together.

[0104] It should be noted that the "bonding method through adhesive slurry" is not the only way to connect the "top support end of the lower inclined support pile 3" and the part of the enclosure near the bottom of the pit. In other embodiments, the connection can also be achieved by using claw gripping.

[0105] Specifically, see Figure 3 ,

[0106] A claw head 14 may be provided at the top support end of the lower inclined support pile 3. The claw head 14 is provided with a plurality of claws. The claw head 14 may be fixed at the top support end of the lower inclined support pile 3, or may be assembled at the top support end of the lower inclined support pile 3 through a hinge (ball hinge or axle pin hinge). When the top support end of the lower inclined support pile 3 is supported on the retaining structure 5, the claw head 14 can firmly grasp the retaining structure 5, thereby realizing the connection between the "top support end of the lower inclined support pile 3" and the position of the retaining structure near the bottom of the pit.

[0107] As mentioned above, an inclinometer 19 is pre-buried inside the retaining structure 5. During the construction of the foundation pit, the top support force mechanism 11 can be controlled to apply thrust to the lower diagonal support pile 3 according to the detection data of the inclinometer 19, thereby controlling the top support prestress applied by the lower diagonal support pile 3 to the retaining near the bottom of the pit, so that the displacement deformation of the retaining near the bottom of the pit meets the design requirements of the foundation pit project.

[0108] It should be noted that the previously mentioned "the reaction corbel 9 is installed on the horizontal support 16 near the pit bottom" refers to, specifically, the reaction corbel 9 is arranged on the upper part of the horizontal support 16 near the pit bottom, the force-applying end of the lower oblique support pile 3 is assembled and connected with the reaction corbel 9 above the horizontal support 16 near the pit bottom, and the top supporting end of the lower oblique support pile 3 is supported together with the top supporting end of the enclosure near the pit bottom below the horizontal support 16 near the pit bottom. Therefore, the lower oblique support pile 3 needs to penetrate the horizontal support 16 near the pit bottom and the reaction corbel 9.

[0109] To this end, before installing the lower oblique support pile 3, an oblique through hole is pre-opened at the position where the reaction corbel 9 is set on the horizontal support 16 near the bottom of the pit as a support through hole, and the direction of the support through hole matches the direction of "the lower oblique support pile 3 penetrating the horizontal support 16 near the bottom of the pit", and the lower oblique support pile 3 penetrates the horizontal support 16 near the bottom of the pit through the support through hole.

[0110] This embodiment 1 also provides a method for applying top support prestressing to the enclosure in the foundation pit. The method for applying top support prestressing adopts the above-mentioned downward inclined prestressed top support structure to apply top support prestressing to the enclosure structure 5, especially to apply top support prestressing to the enclosure near the bottom of the pit.

[0111] Specifically, the method for applying top support prestressing in this embodiment includes:

[0112] S1, construct a horizontal support 16 near the bottom of the foundation pit at the construction location of the foundation pit.

[0113] It should be noted that the horizontal support 16 near the pit bottom is constructed based on the anti-pulling piles 6 pre-constructed in the foundation pit.

[0114] S2, after completing the construction of the horizontal support 16 near the pit bottom in step S1, immediately start to construct the oblique downward prestressed top support structure, and complete the construction of the oblique downward prestressed top support structure before the subsequent lower level excavation operation.

[0115] Those skilled in the art will understand that the displacement and deformation of the retaining structure 5 usually occurs after the lower level excavation operation. After the lower level excavation operation, the free surface of the retaining structure 5 is no longer supported by the soil, and the retaining structure 5 will be displaced and deformed toward the inside of the foundation pit.

[0116] In this embodiment, a downward inclined prestressed top support structure for the surrounding area near the bottom of the pit is constructed before the lower-level excavation operation. During the lower-level excavation operation, the application of top support prestress can be adjusted at any time according to the displacement and deformation of the surrounding area near the bottom of the pit, including the surrounding structure 5 that is still in the soil below the current pit bottom. That is, measures for applying top support prestress can be taken as soon as displacement and deformation occur in the surrounding area near the bottom of the pit, which is conducive to timely preventing displacement and deformation of the surrounding area near the bottom of the pit.

[0117] The specific structural composition of the constructed oblique downward prestressed top support structure is as described above and will not be repeated here.

[0118] The following introduces a specific construction method of the oblique downward prestressed top support structure, which specifically includes steps S21 to S24.

[0119] S21, opening a support hole on the horizontal support 16 near the pit bottom;

[0120] Then, a reaction bracket 9 is constructed on the constructed horizontal support 16 near the pit bottom, and the bracket hole of the reaction bracket 9 should correspond to the support through hole on the horizontal support 16 near the pit bottom;

[0121] In addition, the anchor bolts 111 and the anchor steel plates 112 must be buried in advance.

[0122] S22, at the current bottom of the foundation pit, according to the pre-designed position angle, use an inclined pile driver to obliquely send the lower oblique support pile 3 through the corbel hole of the reaction corbel 9 and the support through hole on the horizontal support 16 near the bottom of the pit into the soil, with the top support end of the lower oblique support pile 3 facing the direction of sending until the top support end of the lower oblique support pile 3 contacts the retaining structure 5.

[0123] As mentioned above, in this embodiment, four grouting passages are arranged in the lower inclined support pile 3, while in other embodiments, the lower inclined support pile 3 may not be provided with a grouting passage, but a claw head 14 is arranged at the top support end of the lower inclined support pile 3. These arrangements are all prepared for the subsequent connection between the "top support end of the lower inclined support pile 3" and the surrounding pit bottom.

[0124] It is important to explain here that "using an inclined pile driver to send the lower inclined support pile 3 obliquely into the soil until the top support end of the lower inclined support pile 3 contacts the retaining structure 5" is a key step in realizing the advance application of top support prestressing. It is the "oblique downward sending" that enables the top support end of the lower inclined support pile 3 to be supported in the soil below the pit bottom on the retaining structure near the pit bottom, thereby creating conditions for the advance intervention of top support prestressing. Therefore, before the subsequent lower-level excavation operation, the retaining structure 5 that is still in the soil can be supported to realize the advance intervention of top support prestressing.

[0125] S23, connecting the top support end of the lower diagonal support pile 3 to the surrounding structure 5.

[0126] Specifically, in this embodiment,

[0127] A grouting machine is used to pour the pre-prepared high-strength bonding slurry from the force-applying end of the lower inclined support pile 3 into the grouting passage inside the lower inclined support pile 3. The bonding slurry is delivered to the part where the "top supporting end of the lower inclined support pile 3" is in contact with the retaining structure 5 through the grouting passage. After the bonding slurry solidifies, the "top supporting end of the lower inclined support pile 3" is connected to the retaining structure 5.

[0128] If, as mentioned above, in other embodiments, the lower inclined support pile 3 is not provided with a grouting passage, but a claw head 14 is provided at the top support end of the lower inclined support pile 3, then the inclined pile driver can directly force the top support end of the lower inclined support pile 3 against the retaining structure 5, so that the claws of the claw head 14 at the top support end of the lower inclined support pile 3 are embedded in the main body of the retaining structure 5, thereby realizing a bite-type connection, and the "top support end of the lower inclined support pile 3" is connected to the retaining structure 5.

[0129] It should be noted that if the connection is made by bonding with adhesive slurry, before pouring the adhesive slurry, water can be sprayed through the grouting passage of the lower oblique support pile 3 to the "position where the top support end of the lower oblique support pile 3 and the surrounding structure 5 are in contact" to remove the soil debris at that position, so as to ensure the firmness of the subsequent adhesive connection.

[0130] S24, installing a top support force adding mechanism 11 based on the horizontal support 16 near the bottom of the pit;

[0131] Specifically,

[0132] The top support force adding mechanism 11 is installed based on the reaction force bracket 9 pre-set on the horizontal support 16 near the bottom of the pit; the force adding end of the lower diagonal support pile 3 is assembled with the top support force adding mechanism 11. In this way, the top support force adding mechanism 11 can apply thrust to the lower diagonal support pile 3, so that the top support end of the lower diagonal support pile 3 can be stably supported on the enclosure structure 5.

[0133] The specific structure of the supporting force mechanism 11 can be found in the previous introduction and will not be repeated here.

[0134] S3, using the oblique downward prestressed top support structure to apply top support prestress to the horizontal support 16 near the pit bottom.

[0135] Specifically,

[0136] The existing detection means are 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 force mechanism 11 is controlled to drive the lower inclined support piles 3 to apply appropriate top support prestress to the enclosure near the bottom of the pit, so that the deformation of the enclosure near the bottom of the pit can be better controlled.

[0137] The previously mentioned "using existing detection methods to detect the deformation condition of the enclosure near the bottom of the pit" is specifically, in this embodiment, a large number of inclinometers 19 (existing technology) are arranged inside the enclosure structure 5. These inclinometers 19 can detect the deformation condition of the enclosure structure 5, including the deformation condition of the enclosure near the bottom of the pit.

[0138] An embodiment 2 is provided below to specifically illustrate the foundation pit retaining wall displacement deformation advance control system and method of the present invention.

[0139] Implementation 2:

[0140] This embodiment 2 provides a foundation pit retaining wall displacement deformation advance control system and a foundation pit retaining wall displacement deformation advance control method. The control system and control method are improved based on a downward inclined prestressed top support structure in a foundation pit and a method for applying top support prestress to the retaining wall in a foundation pit provided in embodiment 1.

[0141] See also Figure 5 And compare Figure 1 Compared with the first embodiment, the control system and control method of the second embodiment have the following improvements:

[0142] Improvement 1:

[0143] A large number of grouting bags 21 (existing technology) are arranged on the periphery of the retaining structure 5, and these grouting bags 21 are evenly distributed around the periphery of the retaining structure 5. During the construction of the foundation pit project, grouting can be performed in sections into the grouting bags 21 according to the displacement and deformation of the retaining structure 5. In this way, the retaining structure 5 can be protected to prevent the surrounding soil rheology from affecting the retaining structure 5. The application of top support prestressing in combination with the horizontal support 16 near the bottom of the pit can better control the deformation problem during the excavation of the foundation pit project.

[0144] It should be noted that, in order to realize grouting into the grouting bag 21 , a grouting backstage 24 is configured for each grouting bag 21 .

[0145] Improvement 2:

[0146] When the foundation pit engineering is constructed to the designed pit bottom, a water stop steel plate 31 is arranged at the intersection of the lower diagonal support pile 3 and the pit bottom surface.

[0147] It should be noted that the point where the lower diagonal support pile 3 applies the top support prestress to the surrounding structure near the bottom of the pit (that is, the part where the top support end of the lower diagonal support pile 3 is connected to the surrounding structure 5) is below the designed pit bottom. When it is below the designed pit bottom of the foundation pit, a water stop steel plate 31 is set at the intersection of the lower diagonal support pile 3 and the pit bottom surface, and then the bottom plate is cast.

[0148] It should be noted that, currently, the position where the lower inclined support pile 3 applies the top support prestress to the surrounding pit bottom is between the horizontal support near the pit bottom and the pit bottom, and the top support prestress cannot be applied below the pit bottom, and when it is below the pit bottom, water seepage is prone to occur at the intersection of the lower inclined support pile 3 and the pit bottom surface. A water stop steel plate 31 is provided at the intersection of the lower inclined support pile 3 and the pit bottom surface, which can prevent water seepage.

[0149] In other embodiments, if the point where the lower diagonal support piles 3 apply the top support prestress to the surrounding area near the pit bottom is above the designed pit bottom, there is no need to set the water stop steel plate 31.

[0150] Improvement 3:

[0151] A rope lifting device 23 is provided for the lower oblique support pile 3. The rope lifting device 23 is mounted on the horizontal support 16 near the bottom of the pit, and the rope of the rope lifting device 23 is connected to the top support end of the lower oblique support pile 3. The rope lifting device 23 is used to adjust the upper and lower positions of the top support end of the lower oblique support pile 3 when the top support end of the lower oblique support pile 3 reaches the position near the bottom of the pit, or in other words, to adjust the downward angle of the lower oblique support pile 3. The purpose is to accurately adjust the point where the lower oblique support pile 3 applies the top support prestress to the position near the bottom of the pit.

[0152] Improvement 4:

[0153] For each lower diagonal support pile 3, an upper diagonal support pile 29 is also provided, one end of which is connected to the reaction corbel 9, in summary, it is connected to the diagonal support base mentioned above, and the other end of the upper diagonal support pile 29 is connected to the upper part of the enclosure near the bottom support through an upper diagonal support base 28. In this way, the upper diagonal support pile 29 can form an oblique downward support for the diagonal support base based on the upper part of the enclosure near the bottom support, so as to offset the reaction force generated by the lower diagonal support pile 3 on the near-pit bottom horizontal support 16, thereby preventing the "near-pit bottom horizontal support 16 from arching upward and deforming under the reaction force of the lower diagonal support pile 3".

[0154] It should be noted that the upper diagonal support pile 29 is not necessary and may be chosen not to be provided in other embodiments.

[0155] The control system comprises a base purlin; a lower oblique support base purlin is arranged at the end of the oblique downward prestressed top support structure; and the lower oblique support base purlin is constructed together with the support.

[0156] Improvement 5:

[0157] In this embodiment, the edge of the horizontal support 16 near the pit bottom is not directly connected to the purlin 2 on the retaining structure 5, but a certain spacing distance is left, that is, the two are separated by air. For the convenience of subsequent description, the separated portion is referred to as the "device assembly interval".

[0158] A large number of transverse supporting telescopic cylinders 27 are arranged at the assembly interval of the device, so that the transverse supporting telescopic cylinders 27 apply transverse supporting force to the purlin 2 based on the edge of the horizontal support 16 near the bottom of the pit, thereby being able to apply transverse supporting prestress to the enclosure structure 5 through the purlin 2, that is, actively controlling the displacement deformation of the enclosure structure 5 in the transverse direction.

[0159] Afterwards, some piers are set at the device assembly intervals to achieve permanent support for the enclosure structure 5.

[0160] It should be noted that, in some other embodiments, if the enclosure purlin 2 is not provided on the enclosure structure 5 , the device assembly interval refers to the space between the edge of the horizontal support 16 near the pit bottom and the enclosure structure 5 .

[0161] Improvement 6:

[0162] In this implementation, some monitoring equipment is also added to the enclosure support system, as follows:

[0163] An axial force monitoring device 20 is provided on each horizontal support structure 1 (including the horizontal support 16 near the bottom of the pit), and the axial force monitoring device 20 is used to monitor the horizontal axial force of the horizontal support structure 1;

[0164] An intelligent column inclination monitoring system 22 is provided on each pull-out pile 6 , and the intelligent column inclination monitoring system 22 is used to monitor the inclination of the pull-out pile 6 .

[0165] In addition, the control system of this embodiment also includes an intelligent control system background 25. The inclinometer 19, the axial force monitoring device 20 and the intelligent column inclinometer monitoring 22 are all connected to the intelligent control system background 25 through a wireless network (WIFI) to realize data signal connection. The intelligent control system background 25 can receive the detection data of the inclinometer 19, the axial force monitoring device 20 and the intelligent column inclinometer monitoring 22 through the wireless receiver 26.

[0166] The grouting bag 21 and the top support force mechanism 11 are also connected to the intelligent control system background 25 by signal, and can receive the control signal of the intelligent control system background 25, that is, the grouting background 24 and the top support force mechanism 11 are controlled by the intelligent control system background 25.

[0167] The intelligent control system backend 25 is provided with a enclosure deformation control program. By running the enclosure deformation control program, the intelligent control system backend 25 can dynamically control the enclosure deformation control program according to the detection data of the inclinometer 19, the axial force monitoring device 20 and the intelligent column inclinometer 22.

[0168] "The process of the top support force adding mechanism 11 driving the lower inclined support pile 3 to apply top support prestress to the surrounding area near the bottom of the pit"

[0169] as well as

[0170] "Grouting process of grouting bag 21 by grouting background 24",

[0171] This can effectively control the displacement and deformation of the retaining wall near the bottom of the pit.

[0172] It should be noted that the control system can be applied to the entire enclosure structure or to a partial enclosure structure.

[0173] The control system and control method of embodiment 2 have the following main advantages:

[0174] 1) Before the subsequent lower-level excavation operation, an advance control system for displacement and deformation of the foundation pit retaining is constructed. The lower inclined support piles 3 in the control system can apply top support prestress to the retaining near the bottom of the pit based on the horizontal support 16 near the bottom of the pit under the drive of the top support force adding mechanism 11, so that the top support prestress can be applied at the first time when the retaining near the bottom of the pit may be displaced and deformed, so as to timely prevent the retaining near the bottom of the pit from being displaced and deformed, thereby effectively controlling the deformation problem during the excavation of the foundation pit engineering;

[0175] 2) The grouting bag 21 of the control system is arranged on the periphery of the retaining structure 5, so as to protect the retaining structure on the periphery to prevent the situation of "the soil around the foundation pit project has serious rheology and aggravates the displacement and deformation of the retaining structure".

[0176] In addition, the control system and control method of embodiment 2 also have the following other advantages:

[0177] 3) The use of advanced support can effectively control the deformation caused by soil rheology during foundation pit excavation, and solve the problem of being unable to quickly support by pre-supporting the surrounding structure near the excavation surface;

[0178] 4) Add an inclined support (above / below the pit bottom) below the last horizontal support to supplement the advance prestressing effect of the middle support, thereby effectively controlling the deformation near the pit bottom;

[0179] 5) Add an active control device to the oblique support system to actively control the deformation near the pit bottom, which has a better deformation control effect;

[0180] 6) Using the intelligent monitoring system combined with the constrained grouting bag, the intelligent control of the foundation pit deformation is realized through the active control device;

[0181] 7) The active control device can be recycled, which is green and environmentally friendly.

[0182] 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 foundation pit retaining displacement deformation advance control system, characterized in that: The control system comprises a lower diagonal support pile (3); One end of the lower oblique support pile (3) serves as a top support end, and the other end of the lower oblique support pile (3) serves as a force-applying end; The force-adding end of the lower oblique support pile (3) is based on the horizontal support (16) near the bottom of the pit, and the top support end of the lower oblique support pile (3) is supported obliquely downward on the position of the enclosure near the bottom of the pit; A top support force adding mechanism (11) is provided at the base of the diagonal support, and the top support force adding mechanism (11) can apply a thrust to the lower diagonal support pile (3) based on the horizontal support (16) near the bottom of the pit, so that the top support end of the lower diagonal support pile (3) applies a top support prestress to the surrounding area near the bottom of the pit; The diagonal support base is the part on which the upper and lower diagonal support piles (3) of the horizontal support (16) near the bottom of the pit are based; The control system further comprises a grouting bag (21); the grouting bag (21) is arranged on the periphery of the enclosure structure (5), and a grouting backstage (24) is configured for the grouting bag (21).

2. According to claim 1, the foundation pit retaining wall displacement deformation advance control system is characterized by: An inclinometer (19) is arranged inside the enclosure structure (5), an axial force monitoring device (20) is arranged on the horizontal support (16) near the bottom of the pit, and an intelligent column inclinometer (22) is arranged on the anti-pulling pile (6); The control system further comprises an intelligent control system background (25); the inclination measuring device (19), the axial force monitoring device (20) and the intelligent column inclination measuring monitoring (22) are all connected to the intelligent control system background (25) by data signals, and the grouting background (24) and the top support force adding mechanism (11) are controlled by the intelligent control system background (25); The intelligent control system backend (25) can dynamically control the inclination measuring device (19), the axial force monitoring device (20) and the intelligent column inclination measuring monitoring (22) according to the detection data. The top support force adding mechanism (11) drives the lower inclined support pile (3) to apply top support prestressing force to the surrounding area near the bottom of the pit. as well as, The grouting backstage (24) performs the grouting process of the grouting bag (21).

3. The foundation pit retaining system displacement deformation advance control system according to claim 1 is characterized in that: The control system further comprises a water-stop steel plate (31); The position where the lower inclined support pile (3) applies top support prestressing force to the surrounding area near the bottom of the pit is below the bottom of the pit; The water-stop steel plate (31) is arranged at the intersection of the lower diagonal support pile (3) and the pit bottom surface, and is cast together with the bottom plate.

4. The advanced control system for displacement and deformation of foundation pit enclosure according to claim 1 is characterized in that: The control system further comprises an upper diagonal support pile (29), wherein the upper diagonal support pile (29) supports the diagonal support base part based on the upper part of the support near the bottom.

5. According to claim 1, the foundation pit retaining wall displacement deformation advance control system is characterized by: A device assembly space is left between the edge of the horizontal support (16) near the pit bottom and the surrounding structure (5); The control system also includes a transverse supporting telescopic cylinder (27), which is arranged at the device assembly interval, and the transverse supporting telescopic cylinder (27) applies transverse supporting prestress to the enclosure structure (5) based on the edge of the horizontal support (16) near the bottom of the pit.

6. The foundation pit retaining wall displacement deformation advance control system according to claim 1 is characterized in that: The control system further comprises a rope lifting device (23), wherein the rope lifting device (23) is mounted on a horizontal support (16) near the bottom of the pit, and a rope of the rope lifting device (23) is connected to a top support end of a lower oblique support pile (3); The rope lifting device (23) is used to adjust the upper and lower positions of the top supporting end of the lower diagonal supporting pile (3) at the position of the enclosure near the bottom of the pit.

7. The foundation pit retaining wall displacement deformation advance control system according to claim 1 is characterized in that: The control system comprises a base purlin; a lower oblique support base purlin is arranged at the end of the oblique downward prestressed top support structure; and the lower oblique support base purlin is constructed together with the support.

8. A method for advanced control of displacement and deformation of foundation pit support, characterized in that: The control method comprises: S1, construct horizontal support near the bottom of the pit (16); S2, construct an advance control system for displacement and deformation of foundation pit support, and complete the construction of the control system before the subsequent lower level excavation operation; The constructed control system includes a lower diagonal support pile (3); One end of the lower oblique support pile (3) serves as a top support end, and the other end of the lower oblique support pile (3) serves as a force-applying end; The force-adding end of the lower oblique support pile (3) is based on the horizontal support (16) near the bottom of the pit, and the top support end of the lower oblique support pile (3) is supported obliquely downward on the position of the enclosure near the bottom of the pit; A top support force adding mechanism (11) is provided at the base of the diagonal support, and the top support force adding mechanism (11) can apply a thrust to the lower diagonal support pile (3) based on the horizontal support (16) near the bottom of the pit, so that the top support end of the lower diagonal support pile (3) applies a top support prestress to the surrounding area near the bottom of the pit; The diagonal support base is the part on which the upper and lower diagonal support piles (3) of the horizontal support (16) near the bottom of the pit are based; The control system further comprises a grouting bag (21); the grouting bag (21) is arranged on the periphery of the enclosure structure (5), and a grouting backstage (24) is configured for the grouting bag (21); S3, applying top support prestress to the horizontal support (16) near the pit bottom by using a control system; Grouting is performed in sections into the grouting bag (21) according to the displacement and deformation conditions of the enclosure structure (5).

9. The method for advanced control of displacement and deformation of foundation pit support according to claim 8 is characterized in that: An inclinometer (19) is arranged inside the enclosure structure (5), an axial force monitoring device (20) is arranged on the horizontal support (16) near the bottom of the pit, and an intelligent column inclinometer (22) is arranged on the anti-pulling pile (6); The constructed control system also includes an intelligent control system background (25); the inclination measuring device (19), the axial force monitoring device (20) and the intelligent column inclination measuring monitoring (22) are all connected to the intelligent control system background (25) by data signals, and the grouting background (24) and the top support force adding mechanism (11) are controlled by the intelligent control system background (25); The intelligent control system backend (25) is used to dynamically control the inclination measuring device (19), the axial force monitoring device (20) and the intelligent column inclination measuring monitoring (22) according to the detection data. The top support force adding mechanism (11) drives the lower inclined support pile (3) to apply top support prestressing force to the surrounding area near the bottom of the pit. as well as, The grouting backstage (24) performs the grouting process of the grouting bag (21).

10. The method for advanced control of displacement and deformation of foundation pit support according to claim 8, characterized in that: The constructed control system also includes a water-stop steel plate (31); The position where the lower inclined support pile (3) applies top support prestressing force to the surrounding area near the bottom of the pit is below the bottom of the pit; The water-stop steel plate (31) is arranged at the intersection of the lower diagonal support pile (3) and the bottom surface of the pit, and is cast together with the bottom plate.

11. The method for advanced control of displacement and deformation of foundation pit support according to claim 8, characterized in that: The constructed control system also includes upper diagonal support piles (29), and the upper diagonal support piles (29) support the diagonal support base based on the upper part of the near-bottom support.

12. The method for advanced control of displacement and deformation of foundation pit support according to claim 8, characterized in that: The constructed horizontal support (16) near the bottom of the pit has a device assembly space between its edge and the surrounding structure (5); The constructed control system also includes a transverse supporting telescopic cylinder (27), which is arranged at the assembly interval of the device. The transverse supporting telescopic cylinder (27) applies transverse supporting prestress to the enclosure structure (5) based on the edge of the horizontal support (16) near the bottom of the pit.

13. The method for advanced control of displacement and deformation of foundation pit support according to claim 8, characterized in that: The constructed control system also includes a rope lifting device (23), which is mounted on a horizontal support (16) near the bottom of the pit, and the rope of the rope lifting device (23) is connected to the top support end of the lower inclined support pile (3); In the process of constructing the control system, the rope lifting device (23) is used to adjust the upper and lower positions of the top supporting end of the lower diagonal support pile (3) at the position of the enclosure near the bottom of the pit.

14. The method for advanced control of displacement and deformation of foundation pit support according to claim 8, characterized in that: The top supporting end of the lower oblique supporting pile (3) and the top supporting enclosure structure (5) are located in the soil below the current bottom of the foundation pit.

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