A deep foundation pit dewatering water level monitoring device based on a self-calibration feedback type deep foundation pit water level sensor

Abstract

The utility model discloses a deep foundation pit dewatering water level monitoring device based on self -calibration feedback formula deep foundation pit water level sensor belongs to deep foundation pit construction monitoring technical field, and it is high -precision, anti -interference's water level real -time monitoring in the application of deep foundation pit dewatering engineering.

Description

Technical Field

[0001] This utility model relates to the field of deep foundation pit construction monitoring technology, and more specifically to a deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor. Background Technology

[0002] Currently, deep foundation pit dewatering level monitoring faces two major technical bottlenecks:

[0003] Environmental interference: Changes in water temperature within the pit and electromagnetic noise cause sensor output drift;

[0004] Electrode aging: Corrosion of conductive probes or adhesion of mud and sand cause signal attenuation.

[0005] Existing technologies, such as the detection device for deep foundation pit early warning proposed in Publication No. CN211036943U, include a camera, laser equipment, sensors, multi-point displacement sensors, strain gauge sensors, displacement sensors, data comparators, microprocessors, and alarms. This device employs a multi-sensor fusion scheme to achieve comprehensive and automatic geological disaster early warning for deep foundation pits, but it does not solve the problem of long-term electrode stability. Furthermore, traditional temperature compensation relies solely on a single thermistor, which cannot eliminate localized temperature drift caused by uneven probe distribution, leading to inaccurate monitoring.

[0006] Therefore, how to provide a deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0007] In view of this, the present invention provides a deep foundation pit dewatering water level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor, which is suitable for high-precision and interference-resistant real-time water level monitoring in foundation pit dewatering projects.

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

[0009] A deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor, based on a foundation, wherein a foundation pit is formed inside the foundation, comprising:

[0010] A water level sensor includes a sensing unit and a self-calibration circuit module. The sensing unit includes a detector and a compensator. The self-calibration circuit module includes a reference signal generator, a comparator, a microprocessor, a temperature compensation unit, and a feedback communication unit.

[0011] The control center is connected to the water level sensor;

[0012] The controller is electrically connected to both the water level sensor and the control center.

[0013] The detector and the compensator are electrically connected to form a sensing electrode pair. The output of the reference signal generator is electrically connected to the first input of the comparator. The common electrical connection of the sensing electrode pair is electrically connected to the second input of the comparator. The output of the comparator is electrically connected to the signal input of the microprocessor. The output of the temperature compensation unit is electrically connected to the temperature data interface of the microprocessor. The calibration signal output of the microprocessor is electrically connected to the communication interface of the controller through the feedback communication unit. The signal output of the controller is electrically connected to the data interface of the control center.

[0014] Furthermore, the detector is an exposed conductive probe used to sense changes in water level.

[0015] Furthermore, the compensator is an electrode array structure, which is connected in parallel with the detector to form a differential sensing structure. The common terminal of the detector and the compensator is connected to the second input terminal of the comparator.

[0016] Furthermore, the electrode array is composed of spaced conductive probes, the surface of which is covered with an anti-corrosion coating, and the conductive probes are fixed to the inner wall of the pit by an adjustable bracket.

[0017] Furthermore, the temperature compensation unit includes a thermistor compensation network and an operational amplifier compensation circuit.

[0018] Furthermore, the thermistor compensation network includes a negative temperature coefficient thermistor, which is connected in parallel with the compensator. One end of the negative temperature coefficient thermistor is connected to the temperature signal acquisition terminal of the microprocessor, and the other end is grounded.

[0019] Furthermore, the operational amplifier compensation circuit includes: an operational amplifier and a temperature sensing resistor, the two ends of which are respectively connected to the positive terminal of the power supply and the non-inverting input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to a common power connection terminal through an adjustable resistor.

[0020] Furthermore, it also includes a LoRa wireless module, through which the feedback communication unit establishes a bidirectional communication link with the controller.

[0021] As can be seen from the above technical solution, compared with the prior art, this utility model discloses a deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor. The differential structure reduces noise interference; the detector and compensator have the same structure, and the compensator is insulated. When the ambient temperature changes, the resistance changes of the two are similar and can be canceled out by the differential, while the resistance change of the detector when in contact with water is retained, thus accurately reflecting the water level change. In addition, the electrode array can improve the monitoring accuracy, the anti-corrosion coating can protect the probe of the compensator, extend its service life, and ensure long-term stable operation. The dual compensation effectively reduces the temperature influence coefficient and the frequency of LoRa remote calibration and maintenance. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of this utility model;

[0024] Figure 2 This is a schematic diagram of the differential sensing structure provided by this utility model. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] See Figure 1 This utility model discloses a deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor. The device is based on a foundation, with a foundation pit formed inside the foundation, comprising:

[0027] The water level sensor includes a sensing unit and a self-calibration circuit module. The sensing unit includes a detector and a compensator, and the self-calibration circuit module includes a reference signal generator, a comparator, a microprocessor, a temperature compensation unit, and a feedback communication unit.

[0028] The control center is connected to the water level sensor;

[0029] The controller is electrically connected to the water level sensor and the control center, respectively.

[0030] The detector and compensator are electrically connected to form a sensing electrode pair. The output of the reference signal generator is electrically connected to the first input of the comparator. The common electrical connection of the sensing electrode pair is electrically connected to the second input of the comparator. The output of the comparator is electrically connected to the signal input of the microprocessor. The output of the temperature compensation unit is electrically connected to the temperature data interface of the microprocessor. The calibration signal output of the microprocessor is electrically connected to the communication interface of the controller through the feedback communication unit. The signal output of the controller is electrically connected to the data interface of the control center.

[0031] In one specific embodiment, the detector employs an exposed conductive probe, utilizing the conductivity of water to sense water level. When the water level rises, the length of the probe immersed in the water increases, and the cross-sectional area of ​​the conductive path formed by the exposed part and the water increases, resulting in a decrease in probe impedance; when the water level falls, the impedance increases, and the water level height can be linearly reflected by the impedance change.

[0032] In one specific embodiment, the compensator is an electrode array structure, which is connected in parallel with the detector to form a differential sensing structure. The common terminal of the detector and the compensator is connected to the second input terminal of the comparator. The core principle is as follows:

[0033] The detector and compensator have the same structure, and changes in ambient temperature and humidity have the same effect on their impedance (common-mode signal). This interference can be canceled out by a parallel differential structure.

[0034] The detector is exposed to the water, and the impedance change caused by the water level change is a differential mode signal. The compensator does not contact the water because of its insulating coating, and the differential mode signal is contributed only by the detector, thus achieving accurate extraction of the water level signal.

[0035] In one specific embodiment, the electrode array consists of spaced conductive probes, the surface of which is covered with an anti-corrosion coating, and the conductive probes are fixed to the inner wall of the pit by an adjustable bracket.

[0036] In one specific embodiment, see Figure 2 As shown, the detector and compensator are connected in parallel as one arm of a single-arm bridge, forming a Wheatstone bridge with the first resistor R1 and the second resistor R2. When there is no water level change in the deep pit, the detector and compensator experience the same impedance drift due to changes in ambient temperature (e.g., if the temperature increases by 10°C, the impedance of both increases by 0.5Ω), and the bridge output voltage is zero. When the water level rises, the detector impedance decreases by 0.3Ω, while the compensator impedance remains unchanged, and the change in the bridge output voltage is linearly related to the water level.

[0037] Specifically, the detector and the compensator have the same structure, and the compensator is insulated. When the ambient temperature changes, the resistance changes of the two are similar and can be canceled out by differential measurement. The resistance change of the detector when it comes into contact with water is retained, thus accurately reflecting the water level change.

[0038] Specifically, the adjustable support design of the electrode array allows the probe spacing to be adjusted according to the depth of the pit, which improves the monitoring accuracy. Especially in pits of different depths, the spacing adjustment can adapt to different measurement ranges.

[0039] Specifically, the adjustable support is fixed to the inner wall of the pit with expansion bolts, and the probe is arranged vertically downward to ensure that it is evenly immersed in the water when the water level changes.

[0040] Specifically, considering the role of the anti-corrosion coating, the water quality in deep foundation pits may be complex. The anti-corrosion coating can protect the probe of the compensator, extend its service life, and ensure long-term stable operation.

[0041] In one specific embodiment, the temperature compensation unit includes a thermistor compensation network and an operational amplifier compensation circuit.

[0042] The hardware compensation circuit compensates for the effect of temperature on the output signal of the sensing electrode by the resistance change of the thermistor and the voltage compensation of the operational amplifier.

[0043] In one specific embodiment, the thermistor compensation network includes a negative temperature coefficient thermistor, which is connected in parallel with the compensator. One end of the negative temperature coefficient thermistor is connected to the temperature signal acquisition terminal of the microprocessor, and the other end is grounded.

[0044] In one specific embodiment, the operational amplifier compensation circuit includes: an operational amplifier and a temperature sensing resistor, with the two ends of the temperature sensing resistor connected to the positive terminal of the power supply and the non-inverting input terminal of the operational amplifier, respectively, and the output terminal of the operational amplifier connected to a common power connection terminal through an adjustable resistor.

[0045] In one specific embodiment, a LoRa wireless module is also included, through which the feedback communication unit establishes a bidirectional communication link with the controller.

[0046] The specific workflow is as follows: the temperature sensing resistor (PT100) increases in resistance as temperature rises (e.g., 100Ω at 0℃, 138.5Ω at 100℃), causing the voltage at the non-inverting input of the operational amplifier to rise; the operational amplifier (e.g., LM358) forms a non-inverting amplifier circuit, and its output voltage is directly proportional to the temperature (the amplification factor is determined by the feedback resistor and the gain resistor); the output compensation voltage is superimposed on the bridge output through an adjustable resistor to cancel out the voltage deviation caused by temperature. In this embodiment, for every 1℃ increase in temperature, the operational amplifier outputs a 20mV compensation voltage to cancel out the bridge drift of 0.02% / ℃.

[0047] Specifically, the hardware compensation circuit compensates for the compensation delay of the software algorithm in scenarios with rapid temperature changes through the instantaneous response of physical components, thus ensuring the accuracy of the sensor.

[0048] In one specific embodiment, the water level sensor operates as follows:

[0049] The water level sensor includes a detector (an exposed conductive probe) that is in direct contact with the water in the pit. When the water level changes, the length of the probe submerged in the water changes, causing a change in the detector's impedance. For example, as the water level rises, more probes are submerged, reducing the detector's impedance; as the water level falls, the length of the submerged probes shortens, increasing the detector's impedance.

[0050] Interference compensation section: The compensator (an insulated conductive probe) is connected in parallel with the detector to form a differential sensing structure. Because the surface of the compensator is covered with an insulating coating, it does not come into contact with the water and only senses interference factors such as ambient temperature and humidity. When the temperature changes, the impedance of the compensator and the detector will change similarly due to the same environmental factors (common-mode interference). This interference can be canceled by the differential structure, so that the output signal only reflects the water level change (differential-mode signal).

[0051] A single-arm bridge is formed by the detector, compensator, first resistor, and second resistor. Changes in water level cause a change in the impedance of the detector, leading to bridge imbalance and outputting a voltage signal related to the water level.

[0052] The temperature compensation unit compensates for the voltage signal output by the bridge circuit. The thermistor compensation network in the hardware compensation circuit utilizes a negative temperature coefficient thermistor connected in parallel with the compensator. When the temperature changes, the resistance of the thermistor changes, and the negative temperature coefficient thermistor adjusts the voltage across the compensator to counteract the effect of temperature on the detector impedance. The operational amplifier compensation circuit detects temperature changes through a temperature sensor, converts the change into a compensation voltage via an operational amplifier, and superimposes it onto the bridge output to further eliminate temperature drift.

[0053] The comparator compares the voltage signal output from the bridge (reflecting water level changes) with the reference water level signal generated by the reference signal generator, and outputs a deviation value. The microprocessor receives this deviation value and, in conjunction with the ambient temperature data provided by the temperature compensation unit, uses a built-in adaptive filtering algorithm to eliminate signal noise caused by water level fluctuations. Then, based on the deviation value and historical calibration parameters, it generates calibration parameters to correct the water level signal.

[0054] Specifically, the corrected water level signal is transmitted to the controller via a LoRa wireless module. Simultaneously, the feedback communication unit periodically uploads calibration logs, sensor health status, and other information.

[0055] In one specific embodiment, the controller workflow is as follows:

[0056] The controller receives water level signals, calibration parameters, and sensor health status data from the water level sensor via the LoRa wireless module's communication interface. Additionally, the controller receives signals from the weight sensors located in the foundation surrounding the excavation pit; these signals are converted into digital signals via an AD converter. The controller incorporates a digital PID controller, which further processes the water level signal based on the deviation value output by the comparator and temperature compensation data. For example, when the received water level signal deviation exceeds a preset threshold, the controller generates a PWM control signal according to the PID algorithm, adjusting the voltage output circuit to bring the output voltage of the single-arm bridge to zero, thus achieving automatic calibration of the water level sensor. The controller forwards the processed water level data, weight sensor data, and calibration information to the control center via the communication link. Simultaneously, the controller also receives instructions from the control center, such as manual calibration trigger commands, and executes corresponding operations accordingly.

[0057] In one specific embodiment, the control center workflow is as follows:

[0058] Data reception and storage: The control center receives various data from the controller through the communication link with the controller, including real-time water level data, weight sensor data, water level sensor calibration parameters and health status information, and stores this data in the database.

[0059] The control center is equipped with a visual calibration interface that displays real-time data from the water level sensor, calibrated data, temperature compensation curves, and load change curves from the weight sensor. Operators can intuitively understand the changes in the pit water level and the operational status of related equipment. The control center analyzes the stored data, for example, by jointly analyzing water level and weight sensor data to assess the impact of dewatering on the pit's stability. When abnormal data is detected, such as the water level exceeding the warning threshold or excessive soil stress changes shown by the weight sensor, the control center promptly issues an alarm and provides decision support to operators, such as whether to adjust the dewatering plan. Operators can send commands to the controller through the control center, such as manually triggering a calibration command to request the controller to calibrate the water level sensor; or sending parameter adjustment commands to adjust the operating parameters of the water level sensor.

[0060] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor, based on a foundation, wherein a foundation pit is formed inside the foundation, characterized in that, include: A water level sensor includes a sensing unit and a self-calibration circuit module. The sensing unit includes a detector and a compensator. The self-calibration circuit module includes a reference signal generator, a comparator, a microprocessor, a temperature compensation unit, and a feedback communication unit. The control center is connected to the water level sensor; The controller is electrically connected to both the water level sensor and the control center. The detector and the compensator are electrically connected to form a sensing electrode pair. The output of the reference signal generator is electrically connected to the first input of the comparator. The common electrical connection of the sensing electrode pair is electrically connected to the second input of the comparator. The output of the comparator is electrically connected to the signal input of the microprocessor. The output of the temperature compensation unit is electrically connected to the temperature data interface of the microprocessor. The calibration signal output of the microprocessor is electrically connected to the communication interface of the controller through the feedback communication unit. The signal output of the controller is electrically connected to the data interface of the control center.

2. The deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 1, characterized in that, The detector is an exposed conductive probe used to sense changes in water level.

3. The deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 2, characterized in that, The compensator is an electrode array structure, which is connected in parallel with the detector to form a differential sensing structure. The common terminal of the detector and the compensator is connected to the second input terminal of the comparator.

4. The deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 3, characterized in that, The electrode array consists of spaced conductive probes, the surface of which is covered with an anti-corrosion coating, and the conductive probes are fixed to the inner wall of the pit by an adjustable bracket.

5. A deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 1, characterized in that, The temperature compensation unit includes a thermistor compensation network and an operational amplifier compensation circuit.

6. A deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 5, characterized in that, The thermistor compensation network includes a negative temperature coefficient thermistor, which is connected in parallel with the compensator. One end of the negative temperature coefficient thermistor is connected to the temperature signal acquisition terminal of the microprocessor, and the other end is grounded.

7. A deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 5, characterized in that, The operational amplifier compensation circuit includes an operational amplifier and a temperature sensing resistor. The two ends of the temperature sensing resistor are respectively connected to the positive terminal of the power supply and the non-inverting input terminal of the operational amplifier. The output terminal of the operational amplifier is connected to a common power connection terminal through an adjustable resistor.

8. A deep foundation pit dewatering level monitoring device based on a self-calibrating feedback deep foundation pit water level sensor according to claim 1, characterized in that, It also includes a LoRa wireless module, through which the feedback communication unit establishes a bidirectional communication link with the controller.

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