Advanced control system and method for displacement and deformation of foundation pit enclosure

Abstract

Disclosed are an advanced control system and method for displacement and deformation of a foundation pit enclosure. The control system and control method of the present invention comprise: constructing a control system before subsequent lower-level soil excavation operations, the control system comprising a lower inclined support pile (3) and a grouting bladder (21); on the basis of a horizontal support (16) near a pit bottom, providing a jacking force-applying mechanism (11) at an inclined support foundation portion of the lower inclined support pile, and the jacking force-applying mechanism applying a pushing force to the lower inclined support pile on the basis of the horizontal support near the pit bottom, so that a jacking end of the lower inclined support pile applies a jacking pre-stress to a part of an enclosure near the pit bottom; and providing the grouting bladder at the periphery of an enclosure structure (5), and configuring a grouting backend (24) for the grouting bladder. The control system and the control method of the present invention can take measures of applying the jacking pre-stress in the first moments of possible displacement and deformation of the part of the enclosure near the pit bottom, thereby preventing the deformation of the part of the enclosure close to the pit bottom, and effectively controlling deformation during excavation of a foundation pit.

Description

Advanced control system and method for displacement and deformation of foundation pit retaining wall Technical Field

[0001] This invention relates to the field of foundation pit engineering technology, and more particularly to a pre-control system and method for foundation pit retaining displacement and deformation. Background Technology

[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. Against this backdrop, deep foundation pit excavation technology has been widely applied. However, deep foundation pit excavation can have a certain impact on the surrounding environment, potentially causing settlement and displacement of the surrounding strata, thereby affecting the safety of nearby subway tunnels, buildings, etc. To solve this problem, existing technologies have proposed a scheme using concrete support reinforcement devices. The main technical concept is to "use the reinforcement device to apply a lateral thrust outward from the foundation pit to the retaining structure, so as to achieve active control of the displacement of the retaining structure" (see Chinese Patent "A Support System for Active Control of Foundation Pit Displacement and Its Design Method - CN108130910A").

[0003] The current problem is:

[0004] 1) The active control of the current retaining structure displacement can only apply lateral top support prestress to the excavation face of the retaining structure, but cannot apply top support prestress to the retaining structure near the bottom of the pit in advance. Especially before the lower level of the foundation pit structure is completed, it is impossible to apply top support prestress to the retaining structure near the bottom of the pit. As a result, the retaining structure near the bottom of the pit may undergo displacement deformation before the lower level of the foundation pit structure is completed, thus failing to effectively control the deformation of the foundation pit.

[0005] 2) If the soil around the foundation pit is severely rheological, it will aggravate the displacement and deformation of the retaining structure;

[0006] 3) Existing technologies lack the ability to intelligently control the deformation of foundation pits by combining monitoring data. Summary of the Invention

[0007] The purpose of this invention is to provide a pre-control system and method for displacement and deformation of foundation pit retaining walls. The control system is equipped with inclined support piles that can apply top support prestress to the retaining wall near the bottom of the pit based on horizontal support near the bottom of the pit. Grouting bags set around the retaining structure protect the retaining structure. When displacement and deformation may occur near the bottom of the pit, measures to apply top support prestress can be taken at the first moment to prevent displacement and deformation of the retaining wall near the bottom of the pit.

[0008] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0009] A pre-control system for displacement and deformation of foundation pit retaining structure, the control system comprising inclined support piles;

[0010] One end of the inclined support pile serves as the top support end, and the other end of the inclined support pile serves as the force-adding end.

[0011] The force-adding end of the lower inclined bracing pile is based on a horizontal support near the bottom of the pit, and the top support end of the lower inclined bracing pile is inclined downward to support the retaining wall near the bottom of the pit.

[0012] A top-support force-adding mechanism is installed at the foundation of the inclined brace. This top-support force-adding mechanism can apply a thrust to the lower inclined brace pile based on the horizontal support near the bottom of the pit, so that the top support end of the lower inclined brace pile applies top support prestress to the retaining wall near the bottom of the pit.

[0013] The aforementioned diagonal bracing foundation is the part on which the upper and lower diagonal bracing piles of the horizontal support near the bottom of the pit are based;

[0014] The control system also includes grouting bags; the grouting bags are located on the periphery of the retaining structure, and a grouting backstage is configured for the grouting bags.

[0015] Furthermore, an inclination measuring device is installed inside the retaining structure, an axial force monitoring device is installed on the horizontal support near the bottom of the pit, and an intelligent column inclination monitoring device is installed on the pull-out piles.

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

[0017] The intelligent control system backend can dynamically control the system based on the detection data from the inclinometer, axial force monitoring device, and intelligent column inclinometer.

[0018] The jacking and force-increasing mechanism drives the lower inclined bracing piles to apply jacking prestress to the retaining wall near the bottom of the pit.

[0019] as well as,

[0020] The grouting process is monitored in the grouting backstage system.

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

[0022] The location where the downward inclined support pile applies top support prestress to the retaining wall near the bottom of the pit is below the bottom of the pit;

[0023] The water-stop steel plate is installed at the intersection of the lower inclined 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 inclined support piles, which provide support to the inclined support foundation based on the upper part of the near-bottom support of the retaining wall.

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

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

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

[0028] The rope lifting device is used to adjust the vertical position of the top end of the lower inclined support pile near the bottom of the pit.

[0029] Furthermore, the control system includes a base waler; a lower inclined base waler is provided at the end of the downwardly inclined prestressed top support structure; the lower inclined base waler is constructed together with the support.

[0030] A method for proactive control of displacement and deformation of foundation pit retaining structure, the control method comprising:

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

[0032] S2, construct a pre-control system for the displacement and deformation of the foundation pit retaining structure, and complete the construction of the control system before the subsequent excavation work of the next lower level;

[0033] The constructed control system includes inclined support piles;

[0034] One end of the inclined support pile serves as the top support end, and the other end of the inclined support pile serves as the force-adding end.

[0035] The force-adding end of the lower inclined bracing pile is based on a horizontal support near the bottom of the pit, and the top support end of the lower inclined bracing pile is inclined downward to support the retaining wall near the bottom of the pit.

[0036] A top-support force-adding mechanism is installed at the foundation of the inclined brace. This top-support force-adding mechanism can apply a thrust to the lower inclined brace pile based on the horizontal support near the bottom of the pit, so that the top support end of the lower inclined brace pile applies top support prestress to the retaining wall near the bottom of the pit.

[0037] The aforementioned diagonal bracing foundation is the part on which the upper and lower diagonal bracing piles of the horizontal support near the bottom of the pit are based;

[0038] The control system also includes grouting bags; the grouting bags are set on the periphery of the retaining structure and are equipped with grouting back-ends;

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

[0040] Grouting is performed in sections into the grouting bags based on the displacement and deformation of the retaining structure.

[0041] Furthermore, an inclination measuring device is installed inside the retaining structure, an axial force monitoring device is installed on the horizontal support near the bottom of the pit, and an intelligent column inclination monitoring device is installed on the pull-out piles.

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

[0043] The intelligent control system uses data from the inclinometer, axial force monitoring, and intelligent column inclinometer monitoring to dynamically control the system.

[0044] The jacking and force-increasing mechanism drives the lower inclined bracing piles to apply jacking prestress to the retaining wall near the bottom of the pit.

[0045] as well as,

[0046] The grouting process is monitored in the grouting backstage system.

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

[0048] The location where the downward inclined support pile applies top support prestress to the retaining wall near the bottom of the pit is below the bottom of the pit;

[0049] The water-stop steel plate is placed at the intersection of the lower inclined 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 inclined support piles, which provide support to the inclined support foundation based on the upper part of the near-bottom support of the retaining wall.

[0051] Furthermore, the constructed near-bottom horizontal support has an assembly gap between its edge and the retaining structure.

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

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

[0054] During the construction of the control system, the aforementioned rope lifting device is used to adjust the vertical position of the top support end of the lower inclined support pile near the bottom of the pit.

[0055] Furthermore, the top support end of the inclined pile is located in the soil below the current bottom of the foundation pit.

[0056] The main advantages of the control system of the present invention compared to the prior art are as follows:

[0057] 1) Before the subsequent excavation of the lower level, a pre-control system for the displacement and deformation of the foundation pit retaining wall is constructed. The inclined support piles 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. Thus, the top support prestress can be applied as soon as possible when the retaining wall near the bottom of the pit may be displaced or deformed, so as to prevent the displacement and deformation of the retaining wall near the bottom of the pit in a timely manner and effectively control the deformation problem during the excavation of the foundation pit project.

[0058] 2) The grouting bags of the control system are set on the outside of the retaining structure to protect the retaining structure from the outside. This can prevent the soil around the foundation pit from rheologically affecting the displacement and deformation of the retaining structure. Attached Figure Description

[0059] Figure 1 is a schematic diagram of the downwardly inclined prestressed support structure in the foundation pit according to Embodiment 1.

[0060] Figure 2 is a schematic diagram of the connection between the inclined support piles and the retaining structure using adhesive grout in Implementation Method 1.

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

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

[0063] Figure 5 is a schematic diagram of the advanced control system for the displacement and deformation of the foundation pit retaining wall based on Embodiment 2 of the present invention. Detailed Implementation

[0064] First, to facilitate a clear and accurate description of the technical solution later in the text, the following definitions are made in advance:

[0065] Definition 1: The “current pit bottom” mentioned in this article refers to the bottom of the pit during the excavation process of foundation pit construction. The “current pit bottom” is a dynamic concept. Wherever the foundation pit is excavated, that is the “current pit bottom”.

[0066] Definition 2: The “design pit bottom” mentioned in this article refers to the bottom of the foundation pit in the foundation pit engineering design. The “design pit bottom” is a static concept.

[0067] Definition 3: The "near-bottom horizontal support" mentioned in this article refers to the horizontal support structure that has been constructed within the foundation pit and is closest to the current pit bottom. This "near-bottom horizontal support" is a dynamic concept. For example, when the first layer of horizontal support structure is completed, this first layer of horizontal support structure is the near-bottom horizontal support; when the second layer of horizontal support structure is completed, this second layer of horizontal support structure is the near-bottom horizontal support, while the first layer of horizontal support structure is no longer the near-bottom horizontal support.

[0068] Definition 4: The term "retaining structure near the pit bottom" as used in this article refers to the part of the retaining structure adjacent to the current pit bottom. More precisely, it refers to the part from the "near-pit bottom horizontal support" to the "current pit bottom" and a certain distance below the "current pit bottom". This "retaining structure near the pit bottom" is a dynamic concept, which changes with the current position of the pit bottom.

[0069] Definition 5: The “upper part of the retaining structure near the bottom support” mentioned in this article refers to the part of the retaining structure that is close to and above the horizontal support near the bottom support.

[0070] Definition 6: The “retaining support system” mentioned in this article is a broad concept that encompasses all forms of “support structures” and their combinations within the foundation pit that support the retaining structure, such as “upward-sloping support structures” and “horizontal support structures”.

[0071] Definition 7: The "lower-level foundation pit structure" mentioned in this article refers to the deeper foundation pit structure that will be constructed in the next stage of foundation pit construction. This "lower-level foundation pit structure" is a dynamic concept. For example, if the foundation pit is designed with two layers of horizontal support structures, after the first layer of horizontal support structure is constructed, the second layer of horizontal support structure to be constructed next is the lower-level foundation pit structure. After the second layer of horizontal support structure is constructed, the foundation pit bottom structure to be constructed next is also the lower-level foundation pit structure.

[0072] Definition 8: The term "lower-level excavation work" as used in this article refers to the excavation work performed during the construction of a foundation pit before the construction of a deeper layer of the pit structure. This excavation is necessary to create space for the deeper layer of the pit structure. For example, if a foundation pit has two layers of horizontal support structures, after the first layer is completed, excavation is required to create space for the second layer. This excavation work is considered a lower-level excavation operation.

[0073] It should be noted that the advanced control system and method for displacement and deformation of foundation pit retaining walls of the present invention is an improvement based on a downwardly inclined prestressed jacking structure and a method for applying jacking prestress within the foundation pit. The following will first introduce the downwardly inclined prestressed jacking structure and the method for applying jacking prestress within the foundation pit.

[0074] The main concept of the downwardly inclined prestressed jacking structure and the method of applying prestress to the jacking in the foundation pit is as follows:

[0075] Based on the horizontal support near the bottom of the pit, a downwardly inclined support component is installed towards the pit retaining structure. This downwardly inclined support component is supported by the retaining structure near the bottom of the pit.

[0076] Then, a top support force-adding mechanism is configured for the downwardly inclined support component. This top support force-adding mechanism is set on the horizontal support near the bottom of the pit. This top support force-adding mechanism can apply a thrust to the downwardly inclined support component based on the horizontal support near the bottom of the pit, so as to push the downwardly inclined support component to apply top support prestress to the enclosure near the bottom of the pit.

[0077] In this way, prestressed top supports can be applied to the retaining wall near the bottom of the pit without completing the lower-level foundation pit structure. This allows for timely and proactive measures to address displacement and deformation near the bottom of the pit, rather than waiting until the lower-level foundation pit structure is completed.

[0078] The main concept of the inclined downward prestressed top support structure and the method of applying top support prestress in this foundation pit is roughly as described above. The following is a detailed description of the inclined downward prestressed top support structure and the method of applying top support prestress through a specific implementation method (Implementation Method 1).

[0079] Implementation method 1:

[0080] Referring to Figure 1, the foundation pit engineering structure involved in this embodiment 1 will be introduced below.

[0081] Those skilled in the art will understand that the overall engineering structure of the foundation pit mainly includes the retaining structure 5 and the retaining support system, the specific structural configuration of which is as follows:

[0082] The retaining structure 5 is constructed around the perimeter of the foundation pit, and the retaining support system is usually set inside the foundation pit to provide support for the retaining structure 5.

[0083] In this embodiment 1, the retaining support system mainly consists of several layers of horizontal support structures 1. These layers of horizontal support structures 1 are located inside the foundation pit, providing support for the retaining structure 5. For each layer of horizontal support structure 1, a corresponding waler 2 is provided on the retaining structure 5. Each layer of horizontal support structure 1 is connected to the retaining structure 5 through the waler 2, thereby providing support for the retaining structure 5.

[0084] In this embodiment 1, the retaining support system also includes a certain number of tension piles 6. These tension piles 6 are fixedly installed in the foundation pit by tension devices 8 installed at the bottom of the foundation pit. Then, the previously mentioned multi-layer horizontal support structure 1 is connected to the tension piles 6. These tension piles 6 provide vertical support for the horizontal support structure 1.

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

[0086] Referring to Figures 1 to 4, Embodiment 1 provides a downwardly inclined prestressed support structure in the foundation pit. This downwardly inclined prestressed support structure is set up based on the foundation pit engineering structure described above. This downwardly inclined prestressed support structure is used to apply support prestress to the retaining wall near the bottom of the pit, thereby preventing displacement and deformation of the retaining wall near the bottom of the pit in the first instance.

[0087] Referring to Figure 1, the inclined prestressed jacking structure mainly includes numerous inclined piles 3, which are equivalent to inclined support components.

[0088] For ease of description, one end of the lower inclined support pile 3 is called the top support end, and the other end of the lower inclined support pile 3 is called the force-adding end.

[0089] The force-adding ends of these inclined support piles 3 are all set based on the horizontal support 16 near the bottom of the pit. Furthermore, the top support end of the inclined support pile 3 is inclined downward and supports the retaining structure 5 near the bottom of the pit to prevent the retaining structure near the bottom of the pit from displacing and deforming towards the inside of the pit.

[0090] It should be noted that, for ease of description, the part on which the force-adding end of the horizontal support 16 near the bottom of the pit is based is referred to as the "inclined bracing foundation".

[0091] It should be noted that the top end of the finally constructed inclined support pile 3 is located in the soil. In other words, the support of the retaining structure near the bottom of the pit is located in the soil below the current bottom of the pit. This allows for the support of the retaining structure 5, which is still in the soil, before the subsequent excavation work of the next layer, thus achieving advanced prestressed support intervention.

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

[0093] More specifically,

[0094] Referring to Figure 4, the specific structure of the top support force-applying mechanism 11 is as follows:

[0095] The top support and 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 prior art component, which has a through hole inside as a bracket hole for the lower inclined support pile 3 to pass through. The reaction bracket 9 also has a reaction surface (indicated by arrow B in Figure 4).

[0098] The reaction frame 116 is configured like a door frame, and it has a reaction beam 115. The reaction frame 116 is fixed to the reaction bracket 9 by anchor bolts 111, anchor steel plates 112 and other fasteners, specifically at the reaction surface of the reaction bracket 9. In this way, the reaction beam 115 of the reaction frame 116 is directly opposite the force-applying end of the lower inclined support pile 3 (the lower inclined support pile is not shown in the figure).

[0099] A certain gap is left between the reaction beam 115 and the reaction bracket 9 as a jack placement space. The first jack 110 is placed in this jack placement space and is positioned between the "reaction beam 115 of the reaction frame 116" and the "force-applying end of the lower inclined support pile 3". In this way, the first jack 110 can apply a thrust to the force-applying end of the lower inclined 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 inclined support pile 3 based on the near-bottom horizontal support 16, so that the top support end of the lower inclined support pile 3 can apply top support prestress to the near-bottom position of the retaining wall.

[0100] Referring to Figure 2, the top end of the lower inclined support pile 3 is fixedly connected to the bottom of the retaining wall near the pit by means of adhesive grout (as indicated by arrow A in Figure 2). In this way, under the thrust applied by the top support force-adding mechanism 11 to the lower inclined support pile 3, the top end of the lower inclined support pile 3 forms a top support effect on the bottom of the retaining wall near the pit.

[0101] More specifically,

[0102] The lower inclined support pile 3 has four grouting channels (not shown in the figure) inside, and the two ends of the grouting channels are located at the two ends of the lower inclined support pile 3 (the force-adding end and the top support end).

[0103] When constructing a downwardly inclined prestressed top support structure, it is necessary to connect the top support end of the downwardly inclined support pile 3 to the bottom of the retaining wall near the pit. First, the top support end of the downwardly inclined support pile 3 is placed against the retaining structure 5. Then, through the grouting channel, the pre-prepared adhesive grout is injected from the force-adding end of the downwardly inclined support pile 3 to the top support end, that is, the part between the top support end of the downwardly inclined support pile 3 and the bottom of the retaining wall near the pit. After the adhesive grout solidifies, the two are connected together.

[0104] It should be noted that the "bonding method using adhesive grout" is not the only way to connect the "top end of the inclined support pile 3" to the bottom of the retaining wall near the pit. In other embodiments, the connection can also be achieved by using a claw-tooth gripping method.

[0105] Specifically, see Figure 3.

[0106] A claw-tooth head 14 with numerous claw teeth can be installed at the top support end of the lower inclined support pile 3. This claw-tooth head 14 can be fixed to the top support end of the lower inclined support pile 3, or it can be assembled thereusingly via a hinge (ball joint or pin joint). When the top support end of the lower inclined support pile 3 abuts against the retaining structure 5, the claw-tooth head 14 can firmly grip the retaining structure 5, thereby achieving a connection between the top support end of the lower inclined support pile 3 and the retaining structure near the bottom of the pit.

[0107] As mentioned above, a tilt measuring device 19 is pre-embedded inside the retaining structure 5. During the construction of the foundation pit project, the top support force-adding mechanism 11 can be controlled to apply thrust to the lower inclined support pile 3 based on the detection data of the tilt measuring device 19, thereby controlling the top support prestress applied by the lower inclined support pile 3 to the retaining structure near the bottom of the pit, so that the displacement deformation of the retaining structure 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 bracket 9 is installed on the horizontal support 16 near the bottom of the pit" specifically means that the reaction bracket 9 is installed on the upper part of the horizontal support 16 near the bottom of the pit. The force-adding end of the lower inclined support pile 3 is assembled and connected to the reaction bracket 9 above the horizontal support 16 near the bottom of the pit, while the top support end of the lower inclined support pile 3 is supported together with the bottom of the pit near the bottom of the pit below the horizontal support 16. Therefore, the lower inclined support pile 3 needs to penetrate the horizontal support 16 near the bottom of the pit and the reaction bracket 9.

[0109] Therefore, before installing the lower inclined support pile 3, an inclined through hole is pre-drilled at the location where the reaction bracket 9 is set on the horizontal support 16 near the bottom of the pit as a support through hole. The direction of the support through hole matches the direction of "lower inclined support pile 3 penetrating the horizontal support 16 near the bottom of the pit". The lower inclined support pile 3 penetrates the horizontal support 16 near the bottom of the pit through the support through hole.

[0110] Embodiment 1 also provides a method for applying top support prestress to the retaining structure within the foundation pit. This method uses the aforementioned downwardly inclined prestressed top support structure to apply top support prestress to the retaining structure 5, especially for applying top support prestress to the retaining structure near the bottom of the pit.

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

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

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

[0114] S2, after the construction of the horizontal support 16 near the bottom of the pit is completed in step S1, the construction of the inclined downward prestressed top support structure shall begin immediately and be completed before the subsequent excavation work of the next lower level.

[0115] Those skilled in the art will understand that the displacement and deformation of the retaining structure 5 usually occurs after the excavation work of the lower level. After the excavation work of the lower level, the free face of the retaining structure 5 is no longer supported by the soil, and the retaining structure 5 will displace and deform toward the inside of the pit.

[0116] In this embodiment, a downwardly inclined prestressed support structure for the retaining structure near the bottom of the pit is constructed before the excavation work of the lower level. During the excavation work of the lower level, the applied prestress of the support can be adjusted at any time according to the displacement and deformation of the retaining structure near the bottom of the pit, including the retaining structure 5 which is still in the soil below the current pit bottom. That is, the measure of applying prestress of the support can be taken as soon as displacement and deformation occurs in the retaining structure near the bottom of the pit, which is conducive to timely prevention of displacement and deformation of the retaining structure near the bottom of the pit.

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

[0118] The following describes the specific construction method of the inclined downward prestressed top support structure, which includes steps S21 to S24.

[0119] S21, a support through hole is opened on the horizontal support 16 near the bottom of the pit;

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

[0121] In addition, anchor bolts 111 and anchor steel plates 112 should be installed in advance.

[0122] S22, at the current bottom of the foundation pit, according to the pre-designed position and angle, the inclined pile machine is used to drive the lower inclined support pile 3 into the soil obliquely 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. The top support end of the lower inclined support pile 3 faces the direction of insertion until the top support end of the lower inclined support pile 3 contacts the retaining structure 5.

[0123] As mentioned earlier, in this embodiment, the lower inclined support pile 3 is provided with four grouting channels. In other embodiments, the lower inclined support pile 3 may not be provided with grouting channels, but instead a claw tooth head 14 is provided at the top support end of the lower inclined support pile 3. These settings are all to prepare for the subsequent connection between the "top support end of the lower inclined support pile 3" and the bottom of the retaining wall near the pit bottom.

[0124] It is important to emphasize here that the key step of "using an inclined pile driver to drive the lower inclined support pile 3 obliquely into the soil until the top end of the lower inclined support pile 3 contacts the retaining structure 5" is to achieve the pre-application of the top support prestress. It is the "oblique downward driving" that allows the top end of the lower inclined support pile 3 to support the retaining structure near the bottom of the pit in the soil below the pit bottom, thus creating conditions for the pre-application of the top support prestress. This allows the retaining structure 5, which is still in the soil, to be supported before the subsequent excavation work of the next layer, so as to achieve the pre-application of the top support prestress.

[0125] S23 connects the top end of the lower inclined support pile 3 to the retaining structure 5.

[0126] Specifically, in this implementation method...

[0127] Using a grouting machine, the pre-prepared high-strength adhesive grout is injected into the grouting channel inside the lower inclined support pile 3 from the force-adding end of the lower inclined support pile 3. The adhesive grout is delivered through the grouting channel to the part where the "top support end of the lower inclined support pile 3" abuts against the retaining structure 5. After the adhesive grout solidifies, the "top support 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 instead a claw tooth head 14 is provided at the top support end of the lower inclined support pile 3, then the inclined pile machine can directly forcefully press the top support end of the lower inclined support pile 3 against the retaining structure 5, so that the claw teeth of the claw tooth head 14 at the top support end of the lower inclined support pile 3 are embedded into the body of the retaining structure 5, thereby achieving an interlocking 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 bonding method is to use adhesive grout, before injecting the adhesive grout, water can be sprayed through the grouting channel of the lower inclined support pile 3 to the part where the top end of the lower inclined support pile 3 abuts against the retaining structure 5 to remove soil debris in that part, so as to ensure the firmness of the bonding connection later.

[0130] S24, a top support force-adding mechanism 11 is installed 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 bracket 9 pre-installed on the horizontal support 16 near the bottom of the pit; the force-adding end of the lower inclined 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 a thrust to the lower inclined support pile 3, so that the top support end of the lower inclined support pile 3 can stably support the retaining structure 5.

[0133] The specific structure of the top support force-adding mechanism 11 is described in the previous introduction and will not be repeated here.

[0134] S3, apply top support prestress to the horizontal support 16 near the bottom of the pit using a downwardly inclined prestressed top support structure.

[0135] Specifically

[0136] Existing detection methods are used to detect the deformation of the retaining wall near the bottom of the pit (deformation data). Based on the deformation of the retaining wall near the bottom of the pit and in accordance with the design standards, the top support force-adding mechanism 11 drives the lower inclined support pile 3 to apply appropriate top support prestress to the retaining wall near the bottom of the pit, so that the deformation of the retaining wall near the bottom of the pit can be better controlled.

[0137] The previously mentioned "using existing detection methods to detect the deformation of the retaining structure near the bottom of the pit" specifically refers to the following: in this embodiment, numerous inclinometers 19 (existing technology) are installed inside the retaining structure 5. These inclinometers 19 can detect the deformation of the retaining structure 5, including the deformation of the retaining structure near the bottom of the pit.

[0138] The following is a second embodiment to specifically illustrate the pre-control system and method for displacement and deformation of foundation pit retaining structure according to the present invention.

[0139] Implementation Method 2:

[0140] This embodiment 2 provides a pre-control system for the displacement and deformation of foundation pit retaining walls and a pre-control method for the displacement and deformation of foundation pit retaining walls. The control system and control method are improved based on the pre-stressed jacking structure in the foundation pit and the method for applying jacking prestress to the retaining wall in the foundation pit provided in embodiment 1.

[0141] Referring to Figure 5 and comparing it with Figure 1, the improvements of the control system and control method in Embodiment 2 compared to Embodiment 1 are as follows:

[0142] Improvement 1:

[0143] Numerous grouting bags 21 (existing technology) are installed around the perimeter of the retaining structure 5, and these grouting bags 21 are evenly distributed around the perimeter of the retaining structure 5. During the construction of the foundation pit, grouting can be injected into the grouting bags 21 in sections according to the displacement and deformation of the retaining structure 5. In this way, the retaining structure 5 can be protected, preventing the rheological changes of the surrounding soil from affecting the retaining structure 5. Combined with the application of top support prestressing by the horizontal support 16 near the bottom of the pit, deformation problems during the excavation of the foundation pit can be better controlled.

[0144] It should be noted that, in order to enable grouting into the grouting bag 21, each grouting bag 21 is equipped with a grouting backstage 24.

[0145] Improvement 2:

[0146] When the foundation pit construction reaches the designed bottom of the pit, a water-stop steel plate 31 is installed at the intersection of the lower inclined support pile 3 and the bottom surface of the pit.

[0147] It should be noted that the point where the lower inclined support pile 3 applies top support prestress to the retaining structure near the bottom of the pit (that is, the part where the top support end of the lower inclined support pile 3 connects to the retaining structure 5) is below the designed pit bottom. When it is below the designed pit bottom, a water-stop steel plate 31 is installed at the intersection of the lower inclined support pile 3 and the pit bottom surface, and then the bottom slab is poured.

[0148] It should be noted that currently, the prestressing point for the inclined support pile 3 near the bottom of the pit is between the horizontal support near the pit bottom and the pit bottom. It is impossible to apply prestressing below the pit bottom, and when below the pit bottom, water seepage is likely to occur at the intersection of the inclined support pile 3 and the pit bottom surface. Therefore, installing a water-stop steel plate 31 at the intersection of the inclined support pile 3 and the pit bottom surface can prevent water seepage.

[0149] In other embodiments, if the point where the lower inclined support pile 3 applies the top support prestress to the retaining wall near the bottom of the pit is above the designed pit bottom, then there is no need to install the waterstop steel plate 31.

[0150] Improvement 3:

[0151] A lifting device 23 is provided for the lower inclined support pile 3. This device 23 is mounted on the horizontal support 16 near the bottom of the pit, and its rope is connected to the top support end of the lower inclined support pile 3. The lifting device 23 is used to adjust the vertical position of the top support end of the lower inclined support pile 3, or in other words, to adjust the downward angle of the lower inclined support pile 3, when the top support end of the lower inclined support pile 3 reaches the bottom of the pit. The purpose is to accurately adjust the point at which the lower inclined support pile 3 applies prestressing to the bottom of the pit.

[0152] Improvement 4:

[0153] For each lower inclined support pile 3, an upper inclined support pile 29 is also provided. One end of the upper inclined support pile 29 is connected to the reaction bracket 9, that is, connected to the aforementioned inclined support foundation. The other end of the upper inclined support pile 29 is connected to the upper part of the retaining wall near the bottom support through an upper inclined support base 28. In this way, the upper inclined support pile 29 can form a downward inclined support at the inclined support foundation based on the upper part of the retaining wall near the bottom support, so as to counteract the reaction force generated by the lower inclined support pile 3 on the near pit bottom horizontal support 16, thereby preventing the "near pit bottom horizontal support 16 from arching and deforming upward under the reaction force of the lower inclined support pile 3".

[0154] It should be noted that the inclined support pile 29 is not mandatory and can be omitted in other embodiments.

[0155] The control system includes a base waler; a lower inclined base waler is installed at the end of the downwardly inclined prestressed top support structure; the lower inclined base waler is constructed together with the support.

[0156] Improvement 5:

[0157] In this embodiment, the edge of the horizontal support 16 near the bottom of the pit is not directly connected to the waler 2 on the enclosure structure 5, but is separated by a certain distance. In other words, the two are separated by a gap. For the convenience of subsequent description, the gap is referred to as the "device assembly gap".

[0158] Numerous lateral support telescopic cylinders 27 are installed at the assembly interval of the device, so that the lateral support telescopic cylinders 27 apply lateral support force to the waler 2 based on the edge of the horizontal support 16 near the bottom of the pit. This enables the application of lateral support prestress to the enclosure structure 5 through the waler 2, that is, to actively control the displacement and deformation of the enclosure structure 5 in the lateral direction.

[0159] Subsequently, some supports were installed at the assembly intervals of the device to provide permanent support for the enclosure structure 5.

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

[0161] Improvement 6:

[0162] In this embodiment, some monitoring devices are also added to the enclosure support system, as follows:

[0163] An axial force monitoring device 20 is installed on each horizontal support structure 1 (including the horizontal support 16 near the bottom of the pit). 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 device 22 is installed on each tension pile 6 to monitor the inclination of the tension pile 6.

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

[0166] The grouting bag 21 and the top support force-adding mechanism 11 are also connected to the intelligent control system backend 25 by signal and can receive control signals from the intelligent control system backend 25. In other words, the grouting backend 24 and the top support force-adding mechanism 11 are controlled by the intelligent control system backend 25.

[0167] The intelligent control system backend 25 is equipped with a retaining wall deformation control program. By running this program, the intelligent control system backend 25 can dynamically control the retaining wall deformation based on the detection data from the inclinometer 19, the axial force monitoring device 20, and the intelligent column inclinometer 22.

[0168] "The process of applying prestressing force to the retaining wall near the bottom of the pit by driving the lower inclined support pile 3 through the top support force-increasing mechanism 11."

[0169] as well as

[0170] "The grouting process of 24 pairs of grouting bags 21 in the grouting backstage"

[0171] This effectively controls 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 part of the enclosure structure.

[0173] The main advantages of the control system and control method of Implementation Method 2 are:

[0174] 1) Before the subsequent excavation of the lower level, a pre-control system for the displacement and deformation of the foundation pit retaining structure is constructed. Under the drive of the top support force-adding mechanism 11, the lower inclined support pile 3 in the control system can apply top support prestress to the retaining structure near the bottom of the pit based on the horizontal support 16 near the bottom of the pit. Thus, the top support prestress can be applied as soon as possible when the retaining structure near the bottom of the pit may be displaced or deformed, so as to prevent the retaining structure near the bottom of the pit from displacing or deforming in time, and thus effectively control the deformation problem during the excavation of the foundation pit project.

[0175] 2) The grouting bag 21 of the control system is set on the periphery of the retaining structure 5, so as to protect the retaining structure from the outside and prevent the situation that "the soil around the foundation pit is severely rheological and aggravates the displacement and deformation of the retaining structure".

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

[0177] 3) The use of advanced support can effectively control the deformation caused by soil rheology during the excavation of the foundation pit, and the problem of not being able to quickly support is solved by the retaining structure near the pre-topped excavation surface;

[0178] 4) An inclined support is added below the last horizontal support (above / below the pit bottom) to supplement the prestressing effect of the intermediate support, thereby effectively controlling the deformation near the pit bottom;

[0179] 5) Adding an active control device to the inclined support system can actively control the deformation near the bottom of the pit, resulting in better deformation control.

[0180] 6) By combining an intelligent monitoring system with constrained grouting bags, intelligent control of the foundation pit deformation can be achieved through an active control device;

[0181] 7) The active control device can be recycled and reused, making it green and environmentally friendly.

[0182] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pre-control system for displacement and deformation of foundation pit retaining walls, characterized in that: The control system includes a lower inclined support pile (3); One end of the lower inclined support pile (3) serves as the top support end, and the other end of the lower inclined support pile (3) serves as the force-adding end; The force-adding end of the lower inclined support pile (3) is based on the horizontal support (16) near the bottom of the pit, and the top support end of the lower inclined support pile (3) is inclined downward and supports the retaining wall near the bottom of the pit. A top support force-adding mechanism (11) is provided at the base of the inclined brace. The top support force-adding mechanism (11) can apply a thrust to the lower inclined brace pile (3) based on the horizontal support (16) near the bottom of the pit, so that the top support end of the lower inclined brace pile (3) applies top support prestress to the retaining near the bottom of the pit. The foundation of the inclined bracing is the part on which the upper and lower inclined bracing piles (3) of the horizontal support (16) near the bottom of the pit are based; The control system also includes a grouting bag (21); the grouting bag (21) is located on the periphery of the enclosure structure (5), and a grouting backstage (24) is provided for the grouting bag (21).

2. The pre-control system for displacement and deformation of foundation pit retaining wall according to claim 1, characterized in that: An inclination measuring device (19) is installed inside the retaining structure (5), an axial force monitoring device (20) is installed on the horizontal support (16) near the bottom of the pit, and an intelligent column inclination monitoring device (22) is installed on the pull-out pile (6). The control system also includes an intelligent control system backend (25); the inclination measuring device (19), axial force monitoring device (20) and intelligent column inclination monitoring (22) are all connected to the intelligent control system backend (25) via data signals; the grouting backend (24) and the top support force-adding mechanism (11) are controlled by the intelligent control system backend (25); The intelligent control system backend (25) can dynamically control the system based on the detection data from the inclinometer (19), axial force monitoring device (20), and intelligent column inclinometer (22). The top support mechanism (11) drives the lower inclined support pile (3) to apply top support prestress to the retaining wall near the bottom of the pit. as well as, Grouting backstage (24) grouting process of grouting bag (21).

3. The pre-control system for displacement and deformation of foundation pit retaining wall according to claim 1, characterized in that: The control system also includes a water-stop steel plate (31); The position where the lower inclined support pile (3) applies top support prestress to the retaining wall near the bottom of the pit is below the bottom of the pit; The water-stop steel plate (31) is set at the intersection of the lower inclined support pile (3) and the bottom surface of the pit, and is cast together with the bottom plate.

4. The pre-deformation control system for foundation pit retaining structure according to claim 1, characterized in that: The control system also includes an upper inclined support pile (29), which provides support to the inclined support foundation based on the upper part of the near-bottom support of the enclosure.

5. The pre-deformation control system for foundation pit retaining structure according to claim 1, characterized in that: There is a gap for device assembly between the edge of the horizontal support (16) near the bottom of the pit and the retaining structure (5); The control system also includes a transverse support telescopic cylinder (27), which is installed at the assembly interval of the device. The transverse support telescopic cylinder (27) applies transverse support prestress to the retaining structure (5) based on the edge of the horizontal support (16) near the bottom of the pit.

6. The pre-deformation control system for foundation pit retaining structure according to claim 1, characterized in that: The control system also includes a rope lifting device (23), which is mounted on a horizontal support (16) near the bottom of the pit. The rope of the rope lifting device (23) is connected to the top support end of the lower inclined support pile (3). The rope lifting device (23) is used to adjust the vertical position of the top end of the lower inclined support pile (3) near the bottom of the pit.

7. The advanced control system for displacement and deformation of foundation pit retaining wall according to claim 1, characterized in that: The control system includes a base waler; a lower inclined base waler is installed at the end of the downwardly inclined prestressed top support structure; the lower inclined base waler is constructed together with the support.

8. A method for advance control of displacement and deformation of foundation pit retaining wall, characterized in that: The control method includes: S1, construct horizontal support near the bottom of the pit (16); S2, construct a pre-control system for the displacement and deformation of the foundation pit retaining structure, and complete the construction of the control system before the subsequent excavation work of the next lower level; The constructed control system includes inclined support piles (3); One end of the lower inclined support pile (3) serves as the top support end, and the other end of the lower inclined support pile (3) serves as the force-adding end; The force-adding end of the lower inclined support pile (3) is based on the horizontal support (16) near the bottom of the pit, and the top support end of the lower inclined support pile (3) is inclined downward and supports the retaining wall near the bottom of the pit. A top support force-adding mechanism (11) is provided at the base of the inclined brace. The top support force-adding mechanism (11) can apply a thrust to the lower inclined brace pile (3) based on the horizontal support (16) near the bottom of the pit, so that the top support end of the lower inclined brace pile (3) applies top support prestress to the retaining near the bottom of the pit. The foundation of the inclined bracing is the part on which the upper and lower inclined bracing piles (3) of the horizontal support (16) near the bottom of the pit are based; The control system also includes a grouting bag (21); the grouting bag (21) is set on the periphery of the enclosure structure (5), and a grouting backstage (24) is configured for the grouting bag (21); S3, using the control system to apply top support prestress to the horizontal support (16) near the bottom of the pit; Grouting is performed in sections into the grouting bag (21) according to the displacement and deformation of the retaining structure (5).

9. The method for advance control of displacement and deformation of foundation pit retaining wall according to claim 8, characterized in that: An inclination measuring device (19) is installed inside the retaining structure (5), an axial force monitoring device (20) is installed on the horizontal support (16) near the bottom of the pit, and an intelligent column inclination monitoring device (22) is installed on the pull-out pile (6). The constructed control system also includes an intelligent control system backend (25); the inclination measuring device (19), axial force monitoring device (20) and intelligent column inclination monitoring (22) are all connected to the intelligent control system backend (25) via data signals, and the grouting backend (24) and the top support force-adding mechanism (11) are controlled by the intelligent control system backend (25); The intelligent control system backend (25) dynamically controls the system based on the detection data from the inclinometer (19), axial force monitoring device (20), and intelligent column inclinometer monitoring (22). The top support mechanism (11) drives the lower inclined support pile (3) to apply top support prestress to the retaining wall near the bottom of the pit. as well as, Grouting backstage (24) grouting process of grouting bag (21).

10. The method for advance control of displacement and deformation of foundation pit retaining wall 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 prestress to the retaining wall near the bottom of the pit is below the bottom of the pit; The water-stop steel plate (31) is placed at the intersection of the lower inclined support pile (3) and the bottom surface of the pit, and is cast together with the bottom plate.

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

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

13. The method for advance control of displacement and deformation of foundation pit retaining wall 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). During the construction of the control system, the rope lifting device (23) is used to adjust the vertical position of the top end of the inclined support pile (3) near the bottom of the pit.

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

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