Foundation pit supporting system deformation early warning method based on temperature compensation algorithm

Abstract

The invention relates to a foundation pit supporting system deformation early warning method based on a temperature compensation algorithm. The method is suitable for the technical field of foundation pit engineering. According to the technical scheme, the foundation pit supporting system deformation early warning method based on the temperature compensation algorithm comprises the steps that the strain of a reinforced concrete supporting component in a foundation pit supporting structure and the temperature of the surrounding environment of the foundation pit supporting structure at multiple continuous moments are obtained; based on the strain of the reinforced concrete supporting member at each moment and the ambient temperature, combined with a temperature compensation coefficient, calculating the axial force of the reinforced concrete supporting member considering the temperature influence at each moment; calculating the axial force change rate corresponding to each moment based on the axial force of the reinforced concrete support member considering the temperature influence at each moment; and based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment, judging an early warning state corresponding to each moment.

Description

Technical Field

[0001] The present invention relates to a deformation early warning method for a foundation pit support system based on a temperature compensation algorithm, which is applicable to the technical field of foundation pit engineering. Background Art

[0002] In foundation pit engineering, foundation pit support structures are crucial for ensuring pit safety. Existing pit support structures primarily include reinforced concrete cross bracing and retaining structures. These structures are used to resist the soil loads generated by excavation within the pit, ensuring its stability and safety.

[0003] Typically, deformation monitoring of support structures relies on sensing devices such as strain gauges and displacement meters. These devices monitor the strain and displacement of the support structure, helping engineers understand the stress and deformation of the support structure. Existing technologies employ multiple strain gauges deployed throughout the support structure to monitor strain changes in real time. Data analysis software then processes the monitored data to determine the safety status of the support structure.

[0004] Although the existing technology provides a deformation monitoring method for foundation pit support structures, the following problems and shortcomings still exist in practical applications:

[0005] 1. Large impact of temperature changes: Changes in ambient temperature will cause the reinforced concrete support to produce thermal expansion and contraction effects, which in turn affect the strain and displacement monitoring data of the support structure. For example, in the case of large temperature differences, the strain and displacement changes caused by temperature changes will significantly affect the accuracy of the monitoring data;

[0006] 2. Large errors in monitoring data: Due to the strain differences caused by temperature changes, the monitoring data of existing monitoring methods have large errors, making it difficult to accurately reflect the actual stress and deformation of the support structure;

[0007] 3. Lack of effective temperature compensation algorithm: The existing technology lacks an algorithm to effectively compensate for temperature changes, resulting in large deviations in monitoring data under different temperature conditions, which cannot meet the requirements of high-precision deformation monitoring. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: in response to the above-mentioned problems, a deformation early warning method for a foundation pit support system based on a temperature compensation algorithm is provided.

[0009] The technical solution adopted by the present invention is: a deformation early warning method of a foundation pit support system based on a temperature compensation algorithm, comprising:

[0010] Obtain the strain of reinforced concrete supporting components in the foundation pit support structure and the temperature of the environment surrounding the foundation pit support structure at multiple consecutive moments;

[0011] Based on the strain of reinforced concrete support members and the ambient temperature at each moment, combined with the temperature compensation coefficient, the axial force of reinforced concrete support members considering the temperature effect at each moment is calculated;

[0012] Based on the axial force of the reinforced concrete support member considering the temperature effect at each moment, the corresponding axial force change rate at each moment is calculated;

[0013] Based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment, the warning state corresponding to each moment is determined;

[0014] The temperature compensation coefficient includes:

[0015] regularly acquiring the strain of a reinforced concrete specimen and the temperature of the environment surrounding the reinforced concrete specimen at a plurality of consecutive moments, wherein the reinforced concrete specimen is placed in a construction area of a foundation pit support structure;

[0016] The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The latest temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment.

[0017] The calculation of the axial force of the reinforced concrete support member considering the temperature effect at each moment based on the foundation pit support structure strain and the ambient temperature at each moment, combined with the temperature compensation coefficient, includes:

[0018] N c =ε s (E s A s +E c A c )+m'Δt(E s A s +E c A c )

[0019] Where N c A is the axial force of the reinforced concrete supporting member in the foundation pit supporting structure; s is the total area of steel bars in reinforced concrete support members; s is the steel strain in the reinforced concrete support member, which is equal to the concrete strain in the reinforced concrete support member; E s is the elastic modulus of steel bar; A c is the total concrete area of reinforced concrete supporting members; E c is the elastic modulus of concrete; m′ is the temperature compensation coefficient; Δt is the temperature change at each moment compared to the initial moment.

[0020] The step of determining the warning state corresponding to each moment based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment includes:

[0021] When both the absolute value of the axial force and the axial force change rate control indicators have reached 70% of the preset maximum value, or when either the absolute value of the axial force or the axial force change rate reaches more than 85% of the preset maximum value and the other indicator does not reach 70%, it is considered a yellow warning state;

[0022] When both the absolute value of the axial force and the axial force change rate control indicators have reached more than 85% of the preset maximum value, or when either the absolute value of the axial force or the axial force change rate reaches more than 90% of the preset maximum value and the other indicator does not reach 85%, it is considered an orange warning state;

[0023] When both the absolute value of the axial force and the axial force change rate control indicators have reached more than 90% of the preset maximum value, or either control indicator has reached more than 95% of the maximum value, it is considered a red warning state.

[0024] Also includes:

[0025] When a yellow warning status appears, increase the monitoring frequency and strengthen the inspection of each support for cracks and damage;

[0026] When an orange warning appears, in addition to the above measures, if it is an early warning for the entire foundation pit, each excavation process should be checked and improved, and implemented after approval by the design and construction units; if the alarm is for a reinforced concrete support structure on a certain layer, the support on that layer should be reinforced, and the excavation and support installation of that layer should be checked for any violations;

[0027] When a red alert appears, whether it is an overall warning or a partial warning, in addition to completing the above work, corresponding solutions should be immediately formulated according to the specific emergency situation on site, and the construction process or related design parameters should be changed. In emergency situations, the excavation of the foundation pit should be stopped, and the support structure should be repaired and strengthened, and other corresponding construction treatments should be carried out; especially for partial support warnings, it is also necessary to consider whether the support layer will cause the entire foundation pit to become unstable, and whether there will be sudden changes in the soil layer.

[0028] The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment, including:

[0029]

[0030] Where m' is the temperature compensation coefficient; ε s is the steel strain in the reinforced concrete supporting member of the foundation pit supporting structure, which is equal to the concrete strain in the reinforced concrete supporting member; Δt is the temperature change at each moment compared to the initial moment.

[0031] A foundation pit support system deformation early warning device based on a temperature compensation algorithm, comprising:

[0032] A data acquisition module is used to obtain the strain of reinforced concrete supporting components in the foundation pit support structure and the temperature of the environment surrounding the foundation pit support structure at multiple consecutive moments;

[0033] The axial force calculation module is used to calculate the axial force of the reinforced concrete support member at each moment taking into account the temperature effect based on the strain of the reinforced concrete support member and the ambient temperature at each moment, combined with the temperature compensation coefficient;

[0034] A rate calculation module is used to calculate the rate of change of the axial force at each moment based on the axial force of the reinforced concrete support member taking into account the temperature effect at each moment;

[0035] An early warning judgment module is used to judge the early warning state corresponding to each moment based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment;

[0036] The temperature compensation coefficient includes:

[0037] regularly acquiring the strain of a reinforced concrete specimen and the temperature of the environment surrounding the reinforced concrete specimen at a plurality of consecutive moments, wherein the reinforced concrete specimen is placed in a construction area of a foundation pit support structure;

[0038] The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The latest temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment.

[0039] A storage medium stores a computer program that can be executed by a processor, and when the computer program is executed, the steps of the foundation pit support system deformation early warning method based on the temperature compensation algorithm are implemented.

[0040] A foundation pit support system deformation early warning device has a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed, the steps of the foundation pit support system deformation early warning method based on the temperature compensation algorithm are implemented.

[0041] A foundation pit support system deformation early warning system, comprising:

[0042] Strain gauges are embedded in reinforced concrete support members in the foundation pit support structure to collect the strain of the steel bars in the reinforced concrete support members;

[0043] A temperature sensor is provided in the surrounding environment of the foundation pit support structure to collect the temperature of the surrounding environment;

[0044] A data processing module comprises a memory and a processor, wherein the memory stores a computer program executable by the processor, and when the computer program is executed, the steps of the method for early warning deformation of the foundation pit support system based on the temperature compensation algorithm are implemented;

[0045] The early warning module can trigger a corresponding early warning signal based on the early warning status output by the data processing module.

[0046] The beneficial effects of the present invention are as follows: the present invention determines the temperature compensation coefficient under the construction environment of the foundation pit support structure by setting up reinforced concrete specimens in the construction area of the foundation pit support structure, monitoring the strain of the specimens and the temperature changes of the surrounding environment, and then, by monitoring the strain of the reinforced concrete supporting components in the foundation pit support structure and the temperature changes of the surrounding environment, combining the temperature compensation coefficient and the temperature compensation algorithm, the strain difference caused by temperature change is compensated to ensure the accuracy of the monitoring data.

[0047] The present invention determines the temperature compensation coefficient through field tests and regularly updates it according to seasonal temperature changes to ensure the accuracy and applicability of the temperature compensation algorithm and further improve the accuracy of deformation monitoring and early warning.

[0048] Based on accurate monitoring data, the system of the present invention can generate deformation warning information in a timely and accurate manner, thereby improving the accuracy and reliability of the warning system and ensuring that potential deformation risks can be discovered and warned in a timely manner during the construction of foundation pit projects.

[0049] The present invention significantly reduces the impact of temperature changes on the deformation monitoring results of the foundation pit support structure through a temperature compensation algorithm, thereby ensuring the stability and reliability of the data.

[0050] By introducing a temperature compensation algorithm, the present invention solves the problem in the prior art that temperature changes have a significant impact on monitoring data, ensures the accuracy of foundation pit support structure deformation monitoring data and the reliability of the early warning system, and provides a strong guarantee for the safe construction of foundation pit projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Flowchart of the deformation early warning method of the foundation pit support system based on the temperature compensation algorithm in the embodiment.

[0052] Figure 2 4 is a block diagram of a deformation warning device for a foundation pit support system based on a temperature compensation algorithm in an embodiment.

[0053] Figure 3 2 is a system block diagram of the deformation early warning system of the foundation pit support system in the embodiment. DETAILED DESCRIPTION

[0054] Example 1: This example is a deformation early warning method for a foundation pit support system based on a temperature compensation algorithm, which specifically includes the following steps:

[0055] S100: Obtain the strain of reinforced concrete supporting members in the foundation pit supporting structure and the temperature of the environment surrounding the foundation pit supporting structure at multiple consecutive moments.

[0056] In this embodiment, n (n is a positive integer) vibrating-wire strain gauges are embedded in the reinforced concrete support members of each layer of the foundation pit support structure to measure the strain of the steel bars within the reinforced concrete support members. These vibrating-wire strain gauges are placed at key locations within the foundation pit support structure, such as at both ends and in the middle of the concrete cross braces, to ensure comprehensive strain monitoring.

[0057] In this example, temperature sensors are arranged in the surrounding environment of the foundation pit supporting structure, and the temperature changes of the surrounding environment of the foundation pit supporting structure are monitored in real time through the temperature sensors.

[0058] S200. Calculate the axial force of the reinforced concrete support member at each moment taking into account the temperature effect based on the strain of the reinforced concrete support member at each moment and the ambient temperature in combination with the temperature compensation coefficient.

[0059] For reinforced concrete supporting members considering only load effects, the calculation formula for the axial force is:

[0060] N c =σ s A s +σ c A c =ε s E s A s +ε c E c A c (1)

[0061] Where N c is the axial force of the reinforced concrete support member (kN); σ s is the stress of the steel bars in the reinforced concrete support member (kN / mm 2 );A s is the total cross-sectional area of the steel bars (mm 2 );ε s is the steel bar strain; E s is the elastic modulus of steel bar (kN / mm 2 ); σ c is the concrete stress of reinforced concrete support members (kN / mm 2 );A c is the total concrete area (mm 2 );ε c is the concrete strain; Ec is the elastic modulus of concrete (kN / mm 2 ).

[0062] Assume that the steel bar and concrete deform in synergy, that is, ε s =ε c =ε, then formula (1) can be written as:

[0063] N c =ε(E s A s +E c A c ) (2)

[0064] The average strain of the vibrating wire steel strain gauge in the reinforced concrete support member is:

[0065]

[0066] Then, after substituting formula (3) into formula (1), we have:

[0067]

[0068] Where, ε s is the average strain of the steel bar; n is the number of steel bar strain gauges; k j is the calibration coefficient of the jth steel bar strain gauge (kN / Hz 2 );f ji is the monitoring frequency of the j-th steel bar strain gauge at the i-th moment (Hz); f j0 is the initial frequency (Hz) after the jth steel bar strain gauge is installed (at the 0th moment (initial moment)); A js is the cross-sectional area of the corresponding single steel bar (mm 2 ).

[0069] The axial force calculated after considering the temperature effect will be very different from the axial force calculated without considering the temperature effect, especially when the temperature difference is large, the effect will be more obvious. s The strain increment (α s is the thermal expansion coefficient of the steel bar). For reinforced concrete support members, under the synergistic effect of concrete and steel bars, the true strain of the steel bar strain gauge is:

[0070] ε'=ε s +m'(t i -t0) (5)

[0071] Where ε′ is the steel bar strain considering the temperature effect; m′ is the temperature compensation coefficient.

[0072] The strain difference caused by the temperature difference is the strain increment of the steel bar under the influence of temperature. Therefore, the temperature compensation coefficient m'=α s -α c

[0073] ε'=ε s +(α s -α c )(t i -t0) (6)

[0074] In summary, the calculation formula for the axial force of reinforced concrete support considering the influence of temperature is:

[0075] N c =ε'(E s A s +E c A c ) (7)

[0076] That is: N c =ε s (E s A s +E c A c )+m'Δt(E s A s +E c A c )(8)

[0077] where m' = α s -α c ;Δt=t i -t0; t0 is the temperature at the initial moment; t i is the temperature at the i-th moment.

[0078] In this embodiment, a reinforced concrete specimen that can be deformed freely is made at the foundation pit construction site at regular intervals, and a vibrating wire steel bar strain gauge is buried in it. The specimen is then placed at the edge of the foundation pit and a temperature sensor is set nearby so that the specimen is in the same environmental conditions as the support. The specimen is unconstrained. The axial force of the reinforced concrete specimen support is assumed to be N c =0, that is:

[0079]

[0080] In this example, the temperature compensation coefficient is updated regularly by periodically acquiring the information collected by the vibrating wire steel bar strain gauge and temperature sensor in the reinforced concrete specimen and combining it with formula (9).

[0081] In this embodiment, to determine the temperature compensation coefficient under different construction environments, a reinforced concrete specimen, scaled down 1:10 to the same scale as the concrete specimen used during construction, was first fabricated on-site. A vibrating-wire steel bar strain gauge was embedded within it. Four steel bar strain gauges were placed symmetrically at either end, either vertically or horizontally, or diagonally, with each gauge subjected to axial tension or compression. The specimen was then placed near the foundation pit, subjecting it to the same environmental conditions as the supports.

[0082] Before each axial force monitoring of reinforced concrete support structures, the frequency and temperature of the specimen are tested and recorded, and finally summarized and analyzed; at the same time, the strain gauge strain ε of the steel bar in the specimen is calculated according to formula (3). s Perform calculations.

[0083] Finally, the temperature compensation coefficient m′ for the foundation pit support axial force monitoring under the specific environment of the foundation pit is calculated according to formula (9). Considering the large temperature differences between seasons, for foundation pit projects in most areas, field tests need to be repeated every three months to update the temperature compensation coefficient m′.

[0084] S300. Based on the axial force of the reinforced concrete support member considering the temperature effect at each moment, the axial force change rate corresponding to each moment is calculated by comparing the axial force increment at each moment with that at the previous moment and the time interval between the two moments.

[0085] S400: Based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment, determine the warning state corresponding to each moment and generate a corresponding remedial plan.

[0086] A data set was constructed based on the axial force and axial force change rate of each reinforced concrete support component at each moment. The data set was sorted, and the data sets with large deviations between axial force and temperature values were discarded. The component numbers with negative axial force values were calibrated.

[0087] In this embodiment, the component numbers with calibrated negative axial forces are output to the alarm platform, and on-site personnel need to check whether the support is damaged in time (if the calibrated components account for 20% or more of the total number of components, work needs to be stopped to find out the cause of the phenomenon).

[0088] In this example, the relevant monitoring points in the deep foundation pit project are classified into three warning states: yellow, orange, and red, based on severity. Foundation pit monitoring alarms are controlled by two values: the cumulative change in the monitored axial force and the rate of change of the axial force. It is recommended that the warning value range should not exceed 15%.

[0089] (1) When both the absolute value of the actual monitoring axial force and the actual rate of change of the monitoring project have reached 70% of the maximum value, or when one of the absolute value of the actual monitoring axial force and the actual rate of change has reached more than 85% of the maximum value and the other has not reached 70%, it is considered a yellow warning state.

[0090] (2) When both the absolute value of the actual monitored axial force and the actual rate of change of the monitoring project have reached more than 85% of the maximum value, or when one of the absolute value of the actual monitored axial force and the actual rate of change of the monitoring project has reached more than 90% of the maximum value and the other has not reached 85%, it is considered to be an orange warning state.

[0091] (3) When both the absolute value of the actual monitored axial force and the actual rate of change of the monitoring project control indicators have reached more than 90% of the maximum value, or when either control indicator has reached more than 95% of the maximum value, it is considered a red warning. When the rate of change of the actual monitored axial force increases sharply (when the construction environment and conditions are roughly the same, the value obtained from multiple tests increases exponentially), it is also considered a red alert state.

[0092]

[0093] Among them, F is the average value of the measured axial force; f is the design value of the bearing capacity; V0 is the average value of the measured velocity; V is the maximum allowable velocity value.

[0094] The remedial measures to be implemented under each alarm state in this embodiment are:

[0095] ① When a yellow warning appears, increase the monitoring frequency and strengthen the inspection of each support to see if there are cracks and damages.

[0096] ②. When an orange warning appears, in addition to the above measures, if it is an early warning for the entire foundation pit, each process of foundation pit excavation should be checked and improved, and implemented after approval by the design and construction units; if it is an alarm for a certain layer of reinforced concrete support components, the support of that layer should be reinforced, and check whether there are any violations during the excavation and support installation of that layer.

[0097] ③. When a red alert appears, whether it is a full or partial warning, in addition to completing the above work, corresponding solutions should be immediately formulated based on the specific emergency situation on site, changing the construction process or related design parameters. In emergency situations, excavation should be stopped and corresponding construction measures such as repairing and strengthening the support structure should be carried out. In particular, when warning for partial support, it is also necessary to consider whether the support layer will cause the entire foundation pit to become unstable and whether there will be sudden changes in the soil layer.

[0098] Example 2: This example is a deformation warning device for a foundation pit support system based on a temperature compensation algorithm, specifically comprising:

[0099] A data acquisition module is used to obtain the strain of reinforced concrete supporting components in the foundation pit support structure and the temperature of the environment surrounding the foundation pit support structure at multiple consecutive moments;

[0100] The axial force calculation module is used to calculate the axial force of the reinforced concrete support member at each moment taking into account the temperature effect based on the strain of the reinforced concrete support member and the ambient temperature at each moment, combined with the temperature compensation coefficient;

[0101] A rate calculation module is used to calculate the rate of change of the axial force at each moment based on the axial force of the reinforced concrete support member taking into account the temperature effect at each moment;

[0102] An early warning judgment module is used to judge the early warning state corresponding to each moment based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment;

[0103] The temperature compensation coefficient includes:

[0104] regularly acquiring the strain of a reinforced concrete specimen and the temperature of the environment surrounding the reinforced concrete specimen at a plurality of consecutive moments, wherein the reinforced concrete specimen is placed in a construction area of a foundation pit support structure;

[0105] The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The latest temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment.

[0106] Example 3: This example is a storage medium on which a computer program that can be executed by a processor is stored. When the computer program is executed, the steps of the foundation pit support system deformation early warning method based on the temperature compensation algorithm described in Example 1 are implemented.

[0107] Example 4: This example is a foundation pit support system deformation warning device having a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed, the steps of the foundation pit support system deformation warning method based on the temperature compensation algorithm described in Example 1 are implemented.

[0108] Example 5: This example is a deformation early warning system for a foundation pit support system, comprising: a vibrating wire steel bar strain gauge, a temperature sensor, a data processing module, and an early warning module.

[0109] In this example, vibrating-wire steel bar strain gauges and temperature sensors are used to monitor the strain of reinforced concrete support components (such as concrete cross braces) in the foundation pit support structure and the changes in the ambient temperature. The steel bar strain gauges are arranged at key locations of the foundation pit support structure, such as the ends and middle of the concrete cross braces, to ensure comprehensive strain monitoring; the temperature sensor is arranged in the surrounding environment of the foundation pit support structure to monitor the ambient temperature changes in real time.

[0110] In some specific embodiments, during excavation construction, two steel strain gauges are placed symmetrically or diagonally at each end of each concrete cross brace, and a temperature sensor is embedded in the center. These are connected in parallel to form a set of numbered measuring points. All measuring points on the same level of the excavation support structure, i.e., at the same height, are grouped together into a sensor module via wireless transmission. This module measures the strain and temperature data of all reinforced concrete support members within the same level and outputs them to a data processing module.

[0111] In this embodiment, the data processing module has a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed, the steps of the foundation pit support system deformation early warning method based on the temperature compensation algorithm described in Example 1 are implemented.

[0112] In this example, the data processing module receives the strain and temperature data sent by the sensor module through wireless communication, and analyzes and processes the deformation data in combination with the temperature compensation formula to calculate the actual detection axial force value F of each measured component under the temperature compensation condition. i and the actual rate of change V i , and calculate the axial force F of the entire foundation pit t and the actual rate of change V t , and the magnitude of the axial force F of each set ti and the actual rate of change V ti .

[0113] In this embodiment, the early warning module can trigger a corresponding early warning signal based on the early warning status output by the data processing module and display a corresponding remedial plan.

[0114] The following is a specific example:

[0115] A foundation pit is 10m deep and covers a large area. Investigation shows that the temperature of the environment changes greatly, and there is a lack of relevant disaster warning system. The relevant facilities and equipment are complete, the technical data is complete, and the operation and management system is complete.

[0116] (1) Determine the ambient temperature compensation coefficient:

[0117] According to the method in the previous section, the steel bar gauge is embedded in a scaled-down test specimen and placed on the foundation pit site. At the same time, before each monitoring of the axial force of the reinforced concrete support member, the frequency and temperature of the specimen are tested and recorded, and finally summarized and analyzed. The data are shown in Table 1. At the same time, according to formula (3), the strain ε of the steel bar gauge in the specimen is calculated. s Finally, the temperature compensation coefficient m′ in the foundation pit support axial force monitoring under this environment is calculated according to formula (9).

[0118] Table 1

[0119]

[0120] (2) Sensor assembly:

[0121] Select concrete cross bracing supports that need to be monitored at different levels. Place two steel strain gauges at the left and right symmetrical positions or in the diagonal direction at each support, and embed a temperature sensor in the middle. Connect them in parallel to form a group of measuring points and number them. All measuring points on the same layer or the same horizontal plane are grouped into a set and combined into a sensor module through wireless transmission. The strain and temperature data of all components are measured by this module and output to the data processing module.

[0122] (3) Data processing:

[0123] According to the required temperature compensation coefficient m′ and the temperature change obtained by the sensor, the true axial force is calculated according to formula (7). The overall axial force change results are shown in Table 2, and the overall rate change is shown in Table 3. It is known that the design value of the foundation pit bearing capacity f = 4500kN and the maximum allowable rate value V max =1100kN / 12h. The calculated maximum axial force F = 3240kN and the maximum velocity V = 1000kN / 12h. (The maximum value is bolded)

[0124] Table 2

[0125]

[0126] Table 3

[0127]

[0128] (4) Early warning

[0129] Comparing the data at different times, it can be found that only on the fifth day did the rate of change of the axial force exceed the single control index, triggering a yellow warning. Because this was a warning for the entire foundation pit support, remedial plan (1) was implemented: increase the monitoring frequency and strengthen the inspection of each support for cracks and damage.

Claims

1. A deformation early warning method for foundation pit support system based on temperature compensation algorithm, characterized in that: include: Obtain the strain of reinforced concrete supporting components in the foundation pit support structure and the temperature of the environment surrounding the foundation pit support structure at multiple consecutive moments; Based on the strain of reinforced concrete support members and the ambient temperature at each moment, combined with the temperature compensation coefficient, the axial force of reinforced concrete support members considering the temperature effect at each moment is calculated; Based on the axial force of the reinforced concrete support member considering the temperature effect at each moment, the corresponding axial force change rate at each moment is calculated; Based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment, the warning state corresponding to each moment is determined; The temperature compensation coefficient includes: regularly acquiring the strain of a reinforced concrete specimen and the temperature of the environment surrounding the reinforced concrete specimen at a plurality of consecutive moments, wherein the reinforced concrete specimen is placed in a construction area of a foundation pit support structure; The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The latest temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment.

2. The deformation early warning method of foundation pit support system based on temperature compensation algorithm according to claim 1 is characterized in that: The calculation of the axial force of the reinforced concrete support member considering the temperature effect at each moment based on the foundation pit support structure strain and the ambient temperature at each moment, combined with the temperature compensation coefficient, includes: N c =ε s (AND s TO s +E c TO c )+m'Δt(E s TO s +E c TO c ) Where N c A is the axial force of the reinforced concrete supporting member in the foundation pit supporting structure; s is the total area of steel bars in reinforced concrete support members; s is the steel strain in the reinforced concrete support member, which is equal to the concrete strain in the reinforced concrete support member; E s is the elastic modulus of steel bar; A c is the total concrete area of reinforced concrete supporting members; E c is the elastic modulus of concrete; m′ is the temperature compensation coefficient; Δt is the temperature change at each moment compared to the initial moment.

3. The deformation early warning method of foundation pit support system based on temperature compensation algorithm according to claim 1 is characterized in that: The step of determining the warning state corresponding to each moment based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment includes: When both the absolute value of the axial force and the axial force change rate control indicators have reached 70% of the preset maximum value, or when either the absolute value of the axial force or the axial force change rate reaches more than 85% of the preset maximum value and the other indicator does not reach 70%, it is considered a yellow warning state; When both the absolute value of the axial force and the axial force change rate control indicators have reached more than 85% of the preset maximum value, or when either the absolute value of the axial force or the axial force change rate reaches more than 90% of the preset maximum value and the other indicator does not reach 85%, it is considered an orange warning state; When both the absolute value of the axial force and the axial force change rate control indicators have reached more than 90% of the preset maximum value, or either control indicator has reached more than 95% of the maximum value, it is considered a red warning state.

4. The deformation early warning method of foundation pit support system based on temperature compensation algorithm according to claim 3 is characterized in that: Also includes: When a yellow warning status appears, increase the monitoring frequency and strengthen the inspection of each support for cracks and damage; When an orange warning appears, in addition to the above measures, if it is an early warning for the entire foundation pit, each excavation process should be checked and improved, and implemented after approval by the design and construction units; if the alarm is for a reinforced concrete support structure on a certain layer, the support on that layer should be reinforced, and the excavation and support installation of that layer should be checked for any violations; When a red alert appears, whether it is an overall warning or a partial warning, in addition to completing the above work, corresponding solutions should be immediately formulated according to the specific emergency situation on site, and the construction process or related design parameters should be changed. In emergency situations, the excavation of the foundation pit should be stopped, and the support structure should be repaired and strengthened, and other corresponding construction treatments should be carried out; especially for partial support warnings, it is also necessary to consider whether the support layer will cause the entire foundation pit to become unstable, and whether there will be sudden changes in the soil layer.

5. The deformation early warning method of foundation pit support system based on temperature compensation algorithm according to claim 1 is characterized in that: The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment, including: Where m' is the temperature compensation coefficient; ε s is the steel strain in the reinforced concrete supporting member of the foundation pit supporting structure, which is equal to the concrete strain in the reinforced concrete supporting member; Δt is the temperature change at each moment compared to the initial moment.

6. A deformation warning device for foundation pit support system based on temperature compensation algorithm, characterized in that: include: A data acquisition module is used to obtain the strain of reinforced concrete supporting components in the foundation pit support structure and the temperature of the environment surrounding the foundation pit support structure at multiple consecutive moments; The axial force calculation module is used to calculate the axial force of the reinforced concrete support member at each moment taking into account the temperature effect based on the strain of the reinforced concrete support member and the ambient temperature at each moment, combined with the temperature compensation coefficient; A rate calculation module is used to calculate the rate of change of the axial force at each moment based on the axial force of the reinforced concrete support member taking into account the temperature effect at each moment; An early warning judgment module is used to judge the early warning state corresponding to each moment based on the axial force of the reinforced concrete support member at each moment and the axial force change rate corresponding to each moment; The temperature compensation coefficient includes: regularly acquiring the strain of a reinforced concrete specimen and the temperature of the environment surrounding the reinforced concrete specimen at a plurality of consecutive moments, wherein the reinforced concrete specimen is placed in a construction area of a foundation pit support structure; The reinforced concrete specimen is in an unconstrained state, and the axial force of the reinforced concrete specimen is assumed to be 0. The latest temperature compensation coefficient is calculated based on the strain of the foundation pit support structure and the ambient temperature at each moment.

7. A storage medium having stored thereon a computer program executable by a processor, characterized in that: When the computer program is executed, the steps of the deformation early warning method of the foundation pit support system based on the temperature compensation algorithm as described in any one of claims 1 to 5 are implemented.

8. A foundation pit support system deformation early warning device, comprising a memory and a processor, wherein the memory stores a computer program executable by the processor, characterized in that: When the computer program is executed, the steps of the deformation early warning method of the foundation pit support system based on the temperature compensation algorithm as described in any one of claims 1 to 5 are implemented.

9. A deformation early warning system for foundation pit support system, characterized in that: include: Strain gauges are embedded in reinforced concrete support members in the foundation pit support structure to collect the strain of the steel bars in the reinforced concrete support members; A temperature sensor is provided in the surrounding environment of the foundation pit support structure to collect the temperature of the surrounding environment; A data processing module having a memory and a processor, wherein the memory stores a computer program executable by the processor, wherein when the computer program is executed, the steps of the method for early warning deformation of a foundation pit support system based on a temperature compensation algorithm according to any one of claims 1 to 5 are implemented; The early warning module can trigger a corresponding early warning signal based on the early warning status output by the data processing module.

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