Foundation pit deformation pre-control system and construction method thereof

Abstract

The invention provides a foundation pit deformation pre-control system and a construction method thereof.The foundation pit deformation pre-control system comprises an axial force compensation device, a first temperature sensing unit, a second temperature sensing unit and an axial force regulation and control system; the axial force regulation and control system estimates the total amount of supporting axial force needing to be compensated in advance on the current day and the supporting axial force needing to be compensated in advance every hour on the current day according to weather forecast data. The estimated supporting axial force needing to be compensated in advance in each hour of the day is sent to an axial force compensation device, so that the supporting axial force in the foundation pit is compensated in advance before the air temperature drops; and in combination with temperature data sensed by the first temperature sensing unit and the second temperature sensing unit in real time in each hour of the day, the pre-compensated supporting axial force in each hour of the day is corrected. Based on the system, the problem of foundation pit deformation caused by inner support axial force loss caused by extremely cold weather and rapid cooling conditions in the foundation pit excavation process can be solved, and advanced active control over foundation pit deformation is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and particularly relates to a pre-control system for foundation pit deformation and its construction method. Background Technique

[0002] In the construction of extra-large foundation pits adjacent to protected objects, the deformation control requirements of the foundation pits are very strict. An internal support system including a concrete servo control device is usually adopted inside the foundation pit. Its characteristic is that an axial force compensation device is arranged between one end of the concrete internal support and the retaining structure. The hydraulic control system actively controls the deformation of the retaining structure by controlling the corresponding axial force compensation device, so as to realize the active control of the foundation pit deformation.

[0003] However, during the construction stage of the foundation pit, in the face of extremely cold weather or a rapid temperature drop caused by a cold snap, the concrete internal support will shrink significantly due to the temperature drop. At this time, the deformation of the retaining structure will continue to increase within a certain range, which may lead to potential risks in the construction of the foundation pit.

[0004] In view of the problem in the prior art that the concrete internal support will shrink significantly due to the temperature drop, resulting in the deformation of the retaining structure and triggering potential risks in the construction of the foundation pit, those skilled in the art have been looking for solutions. Summary of the Invention

[0005] The purpose of the present invention is to provide a pre-control system for foundation pit deformation and its construction method to solve the problem that the concrete internal support will shrink significantly due to the temperature drop, which in turn causes the deformation of the retaining structure and triggers potential risks in the construction of the foundation pit.

[0006] To solve the above technical problems, the present invention provides a pre-control system for foundation pit deformation, and the pre-control system for foundation pit deformation includes

[0007] Axial force compensation devices, which are arranged between each internal support in the foundation pit and the diaphragm wall;

[0008] A first temperature sensing unit and a second temperature sensing unit, which are respectively arranged on each internal support in the foundation pit and in the air above the current internal support;

[0009] An axial force regulation system, which establishes communication with the axial force compensation devices, the first temperature sensing unit and the second temperature sensing unit, estimates the total amount of support axial force that needs to be pre-compensated on the current day and the support axial force that needs to be pre-compensated per hour on the current day according to the data of the weather forecast, sends the estimated support axial force that needs to be pre-compensated per hour on the current day to the axial force compensation devices to pre-compensate the support axial force in the foundation pit before the temperature drops, and corrects the pre-compensated support axial force per hour on the current day in combination with the temperature data sensed in real time by the first temperature sensing unit and the second temperature sensing unit per hour on the current day.

[0010] Optionally, in the pre-control system for foundation pit deformation, the axial force regulation system includes:

[0011] A communication module that establishes communication with the axial force compensation device, the first temperature sensing unit, the second temperature sensing unit, and the weather forecasting system;

[0012] A receiving module that receives weather forecast data from the weather forecasting system and temperature data sensed by the first temperature sensing unit and the second temperature sensing unit;

[0013] A processing module that estimates the total amount of support axial force that needs to be pre-compensated on the current day and the support axial force that needs to be pre-compensated per hour on the current day based on the temperature drop value of the current day in the area where the foundation pit is located forecasted by the weather forecast of the previous day, and corrects the support axial force that has been pre-compensated per hour on the current day according to the temperature data sensed in real time by the first temperature sensing unit and the second temperature sensing unit per hour on the current day;

[0014] A sending module that sends the support axial force that needs to be pre-compensated per hour on the current day and the corrected support axial force to the axial force compensation device.

[0015] Optionally, in the pre-control system for foundation pit deformation, each axial force compensation device includes a hydraulic jack.

[0016] Optionally, in the pre-control system for foundation pit deformation, the number of the axial force regulation systems is at least one, and it establishes communication with all axial force compensation devices, the first temperature sensing unit, and the second temperature sensing unit.

[0017] Optionally, in the pre-control system for foundation pit deformation, when the number of the axial force regulation systems is less than the number of the axial force compensation devices, each axial force regulation system establishes communication with the axial force compensation devices between the multi-layer internal supports and the diaphragm wall, the first temperature sensing unit and the second temperature sensing unit arranged on the multi-layer internal supports and in the air above the internal supports.

[0018] Optionally, in the pre-control system for foundation pit deformation, when the number of the axial force regulation systems is the same as the number of the axial force compensation devices, each axial force regulation system establishes communication with the axial force compensation device between one layer of internal support and the diaphragm wall, the first temperature sensing unit and the second temperature sensing unit arranged on this layer of internal support and in the air above the internal support.

[0019] Optionally, in the pre-control system for foundation pit deformation, it further includes: a stress sensor and a deformation sensor, which are arranged at one end of the axial force compensation device facing the diaphragm wall, sense the internal stress of the internal support where the axial force compensation device is located and the deformation amount of the diaphragm wall respectively, and transmit the sensed data to the axial force regulation system, and the axial force regulation system further corrects the support axial force that has been pre-compensated per hour on the current day by combining the received sensed data.

[0020] Optionally, in the pre-control system for foundation pit deformation, one end of each axial force compensation device is fixed to each internal support through a mechanical lock, and the other end vertically abuts against the diaphragm wall.

[0021] The present invention also provides a construction method for a pre-control system for foundation pit deformation, and the construction method for the pre-control system for foundation pit deformation includes:

[0022] An axial force compensation device is arranged between each internal support and the diaphragm wall in the foundation pit, and a first temperature sensing unit and a second temperature sensing unit are respectively arranged on each internal support in the foundation pit and in the air above the current internal support;

[0023] Establish communication between the axial force regulation system and the axial force compensation device, the first temperature sensing unit and the second temperature sensing unit;

[0024] The axial force compensation device estimates the support axial force that needs to be pre-compensated every hour on the current day according to the axial force regulation system, and pre-compensates the support axial force in the foundation pit before the temperature drops;

[0025] The axial force regulation system corrects the pre-compensated support axial force every hour on the current day according to the temperature data sensed in real time by the first temperature sensing unit and the second temperature sensing unit on the current day;

[0026] The axial force compensation device compensates the support axial force in the foundation pit according to the corrected support axial force of the axial force regulation system.

[0027] Optionally, in the construction method of the pre-control system for foundation pit deformation, the process of the axial force regulation system estimating the support axial force that needs to be pre-compensated every hour on the current day is as follows:

[0028] According to the temperature drop value of the area where the foundation pit is located forecasted by the weather forecast of the previous day, estimate the total amount of support axial force that needs to be pre-compensated on the current day;

[0029] Decompose the total amount of the support axial force into the support axial force that needs to be pre-compensated every hour on the current day according to the hourly temperature situation forecasted by the weather forecast of the previous day.

[0030] Optionally, in the construction method of the pre-control system for foundation pit deformation, the estimation of the total amount of support axial force that needs to be pre-compensated on the current day according to the temperature of the area where the foundation pit is located forecasted by the weather forecast of the previous day is estimated by using the following formula (1):

[0031] F = K str δ Δt (1)

[0032] The parameter values in formula (1) can be calculated according to the following steps and calculation methods:

[0033]

[0034] E equ = E c + (E s - E c )ρ (3)

[0035]

[0036] Wherein, F is the total amount of axial force of the support that needs to be pre-compensated on the current day; δ Δt is the deformation of the internal support; K str is the equivalent spring stiffness of the internal support; m is the horizontal soil resistance coefficient; H is the excavation depth of the foundation pit; h is the distance from the support to the bottom of the pit; D is the horizontal spacing of the support; α is the linear expansion coefficient of temperature; L is the length of the internal support; Δt is the predicted temperature drop value of the current day by the weather forecast; E equ is the equivalent elastic modulus of the internal support; A is the cross-sectional area of the concrete internal support; E c is the elastic modulus of concrete; E s is the elastic modulus of steel bars; ρ is the sectional reinforcement ratio.

[0037] Optionally, in the construction method of the foundation pit deformation pre-control system, the process of the axial force control system correcting the pre-compensated support axial force for each hour of the current day according to the temperature data sensed by the first temperature sensing unit and the second temperature sensing unit in real time for each hour of the current day includes:

[0038] Comprehensively considering the differences between every two of the measured temperature of each internal support in the foundation pit, the measured temperature of the environment where the internal support is located, and the predicted temperature value by the weather forecast for each hour of the current day, the pre-compensated support axial force for each hour of the current day is corrected to reasonably cope with the situation that there is a large difference between the temperature drop value and the weather forecast temperature value during a certain period in the actual process.

[0039] In the foundation pit deformation pre - control system and its construction method provided by the present invention, the foundation pit deformation pre - control system includes: an axial force compensation device, a first temperature sensing unit, a second temperature sensing unit, and an axial force regulation system. The axial force regulation system estimates the total amount of support axial force that needs to be pre - compensated on the current day and the support axial force that needs to be pre - compensated per hour on the current day according to the weather forecast data, sends the estimated support axial force that needs to be pre - compensated per hour on the current day to the axial force compensation device to pre - compensate the support axial force in the foundation pit before the temperature drops, and corrects the pre - compensated support axial force per hour on the current day in combination with the temperature data sensed in real - time by the first temperature sensing unit and the second temperature sensing unit per hour on the current day. The foundation pit deformation pre - control system based on the present invention can adapt to the problem of the loss of the internal support axial force caused by extremely cold weather and rapid temperature drop during the foundation pit excavation process, which in turn causes the deformation of the foundation pit, and realizes the active control of the foundation pit deformation in advance. Brief Description of the Drawings

[0040] By describing the exemplary embodiments of the present disclosure in more detail in conjunction with the accompanying drawings, the above - mentioned and other objects, features, and advantages of the present disclosure will become more obvious. Among them, in the exemplary embodiments of the present disclosure, the same reference numerals generally represent the same components.

[0041] Figure 1 It is a schematic diagram of the foundation pit deformation pre - control system in an embodiment of the present invention;

[0042] Figure 2 It is a flowchart of the construction method of the foundation pit deformation pre - control system in an embodiment of the present invention.

[0043] In the figure:

[0044] 1 - axial force compensation device; 2 - first temperature sensing unit; 3 - second temperature sensing unit. Detailed Description of the Embodiment

[0045] The following further elaborates in detail on the foundation pit deformation pre - control system and its construction method proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description and the claims, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non - precise scales, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0046] Now, the present invention will be further described in detail in conjunction with the accompanying drawings. These drawings are all simplified schematic diagrams, only showing the basic structure of the present invention in a schematic way, so they only show the components related to the present invention.

[0047] In the description of the invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the invention.

[0048] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the invention, "a plurality of" means two or more unless otherwise specifically defined.

[0049] In the invention, unless otherwise clearly specified and defined, terms such as "install", "connect", "join", "fix", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0050] Currently, during the foundation pit construction stage, in the face of extremely cold weather or a rapid temperature drop caused by a cold snap, the concrete internal support will shrink significantly due to the temperature drop. At this time, the deformation of the retaining structure will continue to increase within a certain range, which may then lead to foundation pit construction risks. However, the existing concrete servo control device has a relatively rough axial force application value, making it difficult to perform refined loading according to the actual engineering situation. Moreover, it fails to consider the loss of the support axial force caused by the temperature drop and cannot accurately supplement the axial force of the support in advance for this situation, thus unable to achieve pre-control of the foundation pit deformation. Based on this situation, the inventor proposed the foundation pit deformation pre-control system of the present invention, and the specific content is as follows:

[0051] Please refer to Figure 1, the pre - control system for foundation pit deformation includes: axial force compensation device 1, first temperature sensing unit 2, second temperature sensing unit 3, and axial force regulation system; among them, the axial force compensation device 1 is arranged between each internal support and the diaphragm wall in the foundation pit; the first temperature sensing unit 2 and the second temperature sensing unit 3 are respectively arranged on each internal support in the foundation pit and in the air above the current internal support; the axial force regulation system establishes communication with the axial force compensation device 1, the first temperature sensing unit 2, and the second temperature sensing unit 3, estimates the total amount of support axial force that needs to be pre - compensated on the day according to the temperature drop value data in the weather forecast, and the support axial force that needs to be pre - compensated per hour on the day, sends the estimated support axial force that needs to be pre - compensated per hour on the day to the axial force compensation device 1 to pre - compensate the support axial force in the foundation pit before the temperature drops, and corrects the pre - compensated support axial force per hour on the day in combination with the temperature data sensed by the first temperature sensing unit 2 and the second temperature sensing unit 3 in real time per hour on the day. Preferably, one end of each axial force compensation device 1 is fixed to each internal support by a mechanical lock, and the other end vertically abuts against the diaphragm wall, specifically, it abuts against the waling of the diaphragm wall through a hydraulic jack (or grooves and other structures are also arranged in advance on the diaphragm wall or the waling to ensure the tight connection between the axial force compensation device and the diaphragm wall). In this embodiment, both the first temperature sensing unit 2 and the second temperature sensing unit 3 are temperature sensors.

[0052] Further, the axial force regulation system includes: a communication module, a receiving module, a processing module, and a sending module connected in sequence. Among them, the communication module establishes communication with the axial force compensation device, the first temperature sensing unit, the second temperature sensing unit, and the weather forecast system; the receiving module receives the weather forecast data from the weather forecast system, and the temperature data sensed by the first temperature sensing unit and the second temperature sensing unit; the processing module estimates the total amount of support axial force that needs to be pre - compensated on the day according to the temperature drop value of the foundation pit area forecasted by the weather forecast of the previous day, and the support axial force that needs to be pre - compensated per hour on the day, and corrects the pre - compensated support axial force per hour on the day according to the temperature data sensed by the first temperature sensing unit and the second temperature sensing unit in real time per hour on the day; the sending module sends the estimated support axial force that needs to be pre - compensated per hour on the day and the corrected support axial force to the axial force compensation device.

[0053] Specifically, the process of estimating the total amount of support axial force that needs to be pre - compensated on the day according to the weather forecast data is calculated by the following formula (1):

[0054] F = K str δ Δt (1)

[0055] The parameter values in formula (1) can be calculated according to the following steps and calculation methods:

[0056]

[0057] E equ = E c + (E s - E c ) ρ (3)

[0058]

[0059] Wherein, F is the total amount of support axial force that needs to be pre-compensated on the current day (i.e., the maximum value of the support axial force pre-compensated in advance on the current day); δ Δt is the deformation of the internal support; K str is the equivalent spring stiffness of the internal support; m is the coefficient of horizontal soil resistance; H is the excavation depth of the foundation pit; h is the distance from the support to the bottom of the pit; D is the horizontal spacing of the supports; α is the coefficient of linear thermal expansion; L is the length of the internal support; Δt is the predicted temperature drop value on the current day in the weather forecast; E equ is the equivalent elastic modulus of the internal support; A is the cross-sectional area of the concrete internal support; E c is the elastic modulus of concrete; E s is the elastic modulus of steel bars; ρ is the sectional reinforcement ratio.

[0060] Wherein, the axial force regulation system obtains the predicted temperature drop value in advance through the weather forecast and calculates the value of the reverse axial force that needs to be pre-applied to the internal support according to formulas (1) to (4). The axial force regulation system sends it to the axial force compensation device including hydraulic jacks through wired connection or wireless signal. Then, before the temperature drops, the axial force compensation device controls the hydraulic jacks to apply a reverse pre-load to the diaphragm wall in advance to complete the axial force pre-compensation.

[0061] In this embodiment, each axial force compensation device includes a hydraulic jack. When the hydraulic jack is pushing, it is the process of the axial force compensation device applying the support axial force to the diaphragm wall.

[0062] In this embodiment, the number of the axial force regulation systems is at least one, and it establishes communication with all axial force compensation devices, the first temperature sensing unit and the second temperature sensing unit. It can be understood that the number of axial force regulation systems determines the degree of refinement of the control of the axial force compensation devices. The more the number of axial force regulation systems, the higher the degree of refinement of the control of the axial force compensation devices, and the more timely the corresponding axial force compensation devices can apply the support axial force.

[0063] In one embodiment, the number of the axial force control systems is less than the number of the axial force compensation devices, and each axial force control system establishes communication with the axial force compensation devices between the multiple inner supports and the ground-connected wall, and the first temperature sensing unit and the second temperature sensing unit disposed in the air on and above the multiple inner supports, that is, the same axial force control system controls multiple axial force compensation devices.

[0064] In another embodiment, the number of the axial force control systems is the same as the number of the axial force compensation devices, and each axial force control system establishes communication with an axial force compensation device between an inner support and the ground-connected wall, and a first temperature sensing unit and a second temperature sensing unit disposed in the air on and above the inner support, that is, one axial force control system controls one axial force compensation device.

[0065] Preferably, the foundation pit deformation pre-control system also includes: a stress sensor and a deformation sensor, which are arranged at one end of the axial force compensation device facing the ground-connected wall, respectively sensing the internal stress of the inner support where the axial force compensation device is located and the deformation of the ground-connected wall, and transmitting the sensing data to the axial force control system. The axial force control system further corrects the support axial force that has been pre-compensated for each hour of the day in combination with the received sensing data.

[0066] The role of stress sensors and deformation sensors is to obtain real-time data such as the internal force of concrete supports and the deformation value of foundation pit retaining structures. Then, the comprehensive status of the supports in the foundation pit can be monitored in real time by integrating the multi-dimensional data such as pressure, deformation, and temperature collected by the aforementioned sensors. And based on the above multi-dimensional data, a thermal map of the temperature distribution of the supports in the foundation pit can be drawn in real time, displaying key parameters such as the progress of axial force compensation, and providing historical data backtracking and risk warning functions. In addition, since there are certain empirical values in the calculation formula (such as the equivalent spring stiffness K of the internal support str , temperature linear expansion coefficient α, etc.), the empirical parameters need to be corrected for actual projects. It is precisely because of the existence of the above sensors that historical engineering parameters can be collected, and then by analyzing historical meteorological data and engineering parameters, according to future temperature change trends and internal support shrinkage deformation, the compensation strategy is dynamically optimized. Based on historical compensation data and real-time monitoring results, the temperature linear expansion coefficient α, the equivalent spring stiffness K of the internal support are dynamically corrected. str And other key parameters to adapt to the engineering needs of different regions and different material ratios, thereby improving the adaptability of the device to different engineering scenarios and avoiding control deviations caused by the solidification of empirical parameters.

[0067] The data monitored by the first temperature sensing unit and the second temperature sensing unit are directly sent to the axial force control system. Meanwhile, combined with the diaphragm wall deformation value monitored by the deformation sensor and the axial force value of the concrete internal support, diverse data are comprehensively analyzed. Once the diaphragm wall shows a deformation trend towards the inside of the foundation pit or the axial force of the concrete internal support decays, a wired or wireless signal is sent to the control axial force compensation device through the axial force control system, and the applied pre - axial force is gradually and dynamically increased. (That is, pre - control of foundation pit deformation is achieved).

[0068] In addition, pressure sensors can also be installed inside the internal support to monitor the axial force state and magnitude of the concrete internal support.

[0069] Specifically, in addition to integrating the temperature sensing unit, the foundation pit deformation pre - control system of the present invention can also integrate sensors such as stress sensors and deformation sensors. By fusing multi - dimensional data, the comprehensive state of the concrete internal support is monitored in real - time. Thus, according to the multi - dimensional data sensed by the above - mentioned sensors, a thermal distribution map of the internal support temperature in the foundation pit can be drawn in real - time, showing key parameters such as the progress of axial force compensation, and providing functions of historical data backtracking and risk warning. In addition, the foundation pit deformation pre - control system can also analyze historical meteorological data and engineering parameters, and dynamically optimize the compensation strategy based on the future temperature change trend and the shrinkage deformation amount of the internal support. According to historical compensation data and real - time monitoring results, key parameters such as the linear expansion coefficient α of temperature and the equivalent spring stiffness K of the concrete internal support are dynamically corrected str to adapt to the engineering requirements of different regions and different material ratios, thereby improving the adaptability of the device to different engineering scenarios and avoiding control deviations caused by the solidification of empirical parameters.

[0070] In addition, to accelerate the installation speed of the foundation pit deformation pre - control system, the foundation pit deformation pre - control system can be designed as modular units. Each module is connected through a standardized interface, and the number of modules can be flexibly increased or decreased according to the scale of the foundation pit (for example: the number of axial force control systems and axial force compensation devices), and on - site rapid assembly is supported. Thereby reducing the installation and maintenance costs and adapting to different engineering scenarios.

[0071] The foundation pit deformation pre - control system of the present invention can reduce the foundation pit deformation caused by the shrinkage deformation of the internal support in the foundation pit without additional measures, ensuring the safety of foundation pit construction. And according to the real - time weather forecast, axial force compensation for the internal support in the foundation pit can be carried out in advance before a sharp drop in temperature, thereby achieving pre - compensation for deformation and realizing pre - control of the deformation of the retaining structure in advance.

[0072] Correspondingly, this embodiment also provides a construction method for the foundation pit deformation pre - control system. The following refers to Figure 1 and Figure 2 to detail the construction method of the foundation pit deformation pre - control system described in this embodiment.

[0073] First, perform step S1. Set an axial force compensation device between each internal support and the diaphragm wall in the foundation pit, and set a first temperature sensing unit and a second temperature sensing unit on each internal support in the foundation pit and in the air above the current internal support respectively.

[0074] Next, perform step S2. Establish communication between the axial force control system and the axial force compensation device, the first temperature sensing unit, and the second temperature sensing unit.

[0075] Next, perform step S3. The axial force compensation device estimates the support axial force that needs to be pre-compensated for each hour of the day according to the axial force control system, and pre-compensates the support axial force in the foundation pit before the temperature drops. The axial force of the internal support is gradually pre-compensated in advance during the temperature drop process through the foundation pit deformation pre-control system, so as to achieve active pre-control of the foundation pit deformation when encountering extremely cold weather or cold snaps.

[0076] Specifically, the process by which the axial force control system estimates the support axial force that needs to be pre-compensated for each hour of the day is as follows:

[0077] S31: According to the temperature drop value of the day in the area where the foundation pit is located forecasted by the weather forecast of the previous day, estimate the total amount of support axial force that needs to be pre-compensated on the day (that is, estimate the loss amount of the internal support axial force in the foundation pit caused by the total temperature drop on the day); among them, the estimation of the total amount of support axial force that needs to be pre-compensated on the day according to the temperature drop value of the day in the area where the foundation pit is located forecasted by the weather forecast of the previous day adopts the following formula (1) for estimation:

[0078] F = K str δ Δt (1)

[0079] The parameter values in formula (1) can be calculated according to the following steps and calculation methods:

[0080]

[0081] E equ = E c +(E s - E c )ρ (3)

[0082]

[0083] Among them, F is the total amount of support axial force that needs to be pre-compensated on the day (that is, the maximum value of the support axial force pre-compensated on the day); δ Δt is the deformation amount of the internal support; K stris the equivalent spring stiffness of the internal support; m is the coefficient of horizontal soil resistance; H is the excavation depth of the foundation pit; h is the distance from the support to the bottom of the pit; D is the horizontal spacing of the supports; α is the coefficient of linear thermal expansion; L is the length of the internal support; Δt is the predicted temperature drop of the day's weather forecast; E equ is the equivalent elastic modulus of the internal support; A is the cross-sectional area of the concrete internal support; E c is the elastic modulus of concrete; E s is the elastic modulus of steel bars; ρ is the reinforcement ratio of the cross-section.

[0084] S32: Decompose the total amount of support axial force that needs to be pre-compensated into the support axial force that needs to be pre-compensated for each hour of the day according to the hourly temperature conditions forecast by the previous day's weather forecast.

[0085] Next, execute step S4. The axial force control system corrects the pre-compensated support axial force for each hour of the day according to the temperature data sensed in real time by the first temperature sensing unit and the second temperature sensing unit for each hour of the day. Specifically, comprehensively consider the differences between every two of the measured temperature of each internal support in the foundation pit, the measured temperature of the environment where the internal support is located, and the predicted temperature value of the weather forecast for each hour of the day (specifically, compare the three temperatures in pairs, and finally obtain three temperature difference values), and correct the pre-compensated support axial force for each hour of the day to reasonably cope with the situation where there is a large difference between the temperature drop value and the weather forecast temperature value during a certain period in the actual process.

[0086] Based on the first temperature sensing unit and the second temperature sensing unit, historical engineering parameters can be collected. Then, by analyzing historical meteorological data and engineering parameters, according to the future temperature change trend and the shrinkage deformation amount of the internal support, the compensation strategy can be dynamically optimized. According to historical compensation data and real-time monitoring results, dynamically correct key parameters such as the coefficient of linear thermal expansion α and the equivalent spring stiffness K of the internal support str to adapt to the engineering requirements of different regions and different material ratios, and then improve the adaptability of the foundation pit deformation pre-control system to different engineering scenarios, and avoid control deviations caused by the solidification of empirical parameters.

[0087] Next, execute step S5. The axial force compensation device compensates the support axial force in the foundation pit according to the support axial force corrected by the axial force control system.

[0088] Specifically, the above estimation process will be described in combination with an actual scenario. Assume that today's weather forecast predicts that a cold snap will reach the area where the foundation pit is located tomorrow, and the temperature is expected to drop by 10°C. At this time, Δt = 10°C. According to formula (1), the value of the support axial force that needs to be pre-compensated for the internal support of the foundation pit can be calculated to avoid the deformation of the diaphragm wall. However, since the currently calculated F is the total amount of the support axial force that needs to be pre-compensated on the same day, if it is directly compensated to the diaphragm wall at one time, there will be an over-compensation problem, resulting in the cracking of the diaphragm wall. Therefore, F needs to be disassembled and distributed according to the hourly temperature conditions predicted by the previous day's weather forecast (that is, to evaluate the support axial force that needs to be applied to the internal support at each time period according to the hourly temperature change in the weather forecast). Since there may be a difference between the temperature drop value given by the weather forecast and the actual current temperature drop value, that is, there may be a certain error in the pre-compensated support axial force calculated based on the temperature drop value given by the weather forecast. To eliminate this part of the error, the system of the present invention corrects the pre-compensated support axial force based on the actual measured internal support and current ambient temperature by the first temperature sensing unit and the second temperature sensing unit to conform to the support axial force required for the actual temperature drop. The temperature data of the timing sensed by the two temperature sensing units is transmitted to the axial force control system, and a wireless / wired signal is sent to the axial force compensation device through the axial force control system to gradually and dynamically apply the corrected pre-compensated support axial force to the internal support to compensate for the loss of the axial force support caused by the shrinkage of the internal support due to the temperature drop.

[0089] It can be understood that since the temperature difference per hour is small, there will be a large workload for real-time correction of the pre-compensated support axial force. To improve the working efficiency of the axial force control system, the pre-compensated support axial force can be corrected based on the temperature data measured within a predetermined time.

[0090] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0091] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0092] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention according to the above disclosure are within the protection scope of the claims.

Claims

1. A pre-control system for foundation pit deformation, characterized in that, Comprising: An axial force compensation device, disposed between each internal support and the diaphragm wall within the foundation pit; A first temperature sensing unit and a second temperature sensing unit, respectively disposed on each internal support within the foundation pit and in the air above the current internal support; An axial force regulation system, establishing communication with the axial force compensation device, the first temperature sensing unit, and the second temperature sensing unit, estimating the total amount of support axial force that needs to be pre-compensated on the current day and the support axial force that needs to be pre-compensated per hour on the current day according to the temperature drop value data of the weather forecast, sending the estimated support axial force that needs to be pre-compensated per hour on the current day to the axial force compensation device to pre-compensate the support axial force within the foundation pit before the temperature drops, and correcting the pre-compensated support axial force per hour on the current day in combination with the temperature data sensed by the first temperature sensing unit and the second temperature sensing unit in real time per hour on the current day.

2. The pre-control system for foundation pit deformation according to claim 1, wherein The axial force regulation system includes: A communication module, establishing communication with the axial force compensation device, the first temperature sensing unit, the second temperature sensing unit, and the weather forecast system; A receiving module, receiving the weather forecast data from the weather forecast system and the temperature data sensed by the first temperature sensing unit and the second temperature sensing unit; A processing module, estimating the total amount of support axial force that needs to be pre-compensated on the current day and the support axial force that needs to be pre-compensated per hour on the current day according to the temperature drop value of the current day's temperature in the area where the foundation pit is located forecasted by the weather forecast of the previous day, and correcting the pre-compensated support axial force per hour on the current day according to the temperature data sensed by the first temperature sensing unit and the second temperature sensing unit in real time per hour on the current day; A sending module, sending the estimated support axial force that needs to be pre-compensated per hour on the current day and the corrected support axial force to the axial force compensation device.

3. The pre-control system for foundation pit deformation according to claim 1, characterized in that Each axial force compensation device includes a hydraulic jack.

4. The pre-control system for foundation pit deformation according to claim 1, characterized in that, The number of the axial force regulation systems is at least one, establishing communication with all the axial force compensation devices, the first temperature sensing unit, and the second temperature sensing unit.

5. The pre-control system for foundation pit deformation according to claim 4, characterized in that When the number of the axial force regulation systems is less than the number of the axial force compensation devices, each axial force regulation system establishes communication with the axial force compensation devices between multiple internal supports and the diaphragm wall, the first temperature sensing unit and the second temperature sensing unit disposed on the multiple internal supports and in the air above the internal supports.

6. The pre-control system for foundation pit deformation according to claim 4, wherein, When the number of the axial force regulation systems is the same as the number of the axial force compensation devices, each axial force regulation system establishes communication with the axial force compensation device between one internal support and the diaphragm wall, the first temperature sensing unit and the second temperature sensing unit disposed on the internal support and in the air above the internal support.

7. The pre-control system for foundation pit deformation according to claim 1, characterized in that, Further comprising: A stress sensor and a deformation sensor, disposed at one end of the axial force compensation device facing the diaphragm wall, respectively sensing the internal stress of the internal support where the axial force compensation device is located and the deformation amount of the diaphragm wall, and transmitting the sensed data to the axial force regulation system, and the axial force regulation system further corrects the pre-compensated support axial force per hour on the current day in combination with the received sensed data.

8. The pre-control system for foundation pit deformation according to claim 1, characterized in that, One end of each axial force compensation device is fixed to each internal support by a mechanical lock, and the other end vertically abuts against the diaphragm wall.

9. A construction method of a pre-control system for foundation pit deformation, characterized in that, Comprising: An axial force compensation device is provided between each internal support in the foundation pit and the diaphragm wall, and a first temperature sensing unit and a second temperature sensing unit are respectively provided on each internal support in the foundation pit and in the air above the current internal support; Establish communication between the axial force control system and the axial force compensation device, the first temperature sensing unit and the second temperature sensing unit; The axial force compensation device estimates the support axial force that needs to be pre-compensated per hour on the current day according to the axial force control system, and pre-compensates the support axial force in the foundation pit before the temperature drops; The axial force control system corrects the support axial force that has been pre-compensated per hour on the current day according to the temperature data sensed in real time by the first temperature sensing unit and the second temperature sensing unit per hour on the current day; The axial force compensation device compensates the support axial force in the foundation pit according to the support axial force corrected by the axial force control system.

10. The construction method of the foundation pit deformation pre-control system according to claim 9, characterized in that, The process by which the axial force control system estimates the support axial force that needs to be pre-compensated per hour on the current day is as follows: Estimate the total amount of support axial force that needs to be pre-compensated on the current day according to the temperature drop value of the area where the foundation pit is located forecasted by the weather forecast of the previous day; Decompose the total amount of support axial force into the support axial force that needs to be pre-compensated per hour on the current day according to the hourly temperature conditions forecasted by the weather forecast of the previous day.

11. The construction method of the foundation pit deformation pre-control system according to claim 10, characterized in that, The estimation of the total amount of support axial force that needs to be pre-compensated on the current day according to the temperature of the area where the foundation pit is located forecasted by the weather forecast of the previous day is estimated using the following formula (1): F = K str δ Δt (1) The parameter values in formula (1) can be calculated according to the following steps and calculation methods: E equ = E c + (E s - E c ) ρ (3) Among them, F is the total amount of axial force of the support that needs to be pre-compensated on the same day; δ Δt is the deformation of the internal support; K str is the equivalent spring stiffness of the internal support; m is the coefficient of horizontal soil resistance; H is the excavation depth of the foundation pit; h is the distance from the support to the bottom of the pit; D is the horizontal spacing of the support; α is the coefficient of linear expansion due to temperature; L is the length of the internal support; Δt is the predicted temperature drop on the same day as predicted by the weather forecast; E equ is the equivalent elastic modulus of the internal support; A is the cross-sectional area of the concrete internal support; E c is the elastic modulus of concrete; E s is the elastic modulus of steel; ρ is the sectional reinforcement ratio.

12. The construction method of the foundation pit deformation pre-control system according to claim 11, characterized in that, The process by which the axial force control system corrects the support axial force that has been pre-compensated per hour on the current day according to the temperature data sensed in real time by the first temperature sensing unit and the second temperature sensing unit per hour on the current day includes: Comprehensively consider the differences between every two of the measured temperature of each internal support in the foundation pit, the measured temperature of the environment where the internal support is located, and the temperature value estimated by the weather forecast per hour on the current day, and correct the support axial force that has been pre-compensated per hour on the current day to reasonably cope with the situation where there is a large difference between the temperature drop value and the weather forecast temperature value during a certain period in the actual process.

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