Sensor system for extraction of seepage pressure in dams

Abstract

The application belongs to the technical field of intelligent sensors, and relates to a sensing system for dam internal seepage pressure extraction, which comprises a sensing framework module, a primary sensing module, a compensation sensing module and a signal decoupling processing module. The primary sensing module and the compensation sensing module are centrally symmetrically distributed in the sensing framework module and share a driving current source. The compensation sensing module is in a fully closed working condition and is filled with a pressure transmission medium, and is used for sensing a surface layer elastic strain caused by dam structure load. The signal decoupling processing module is associated with a common mode potential between an initial voltage signal and a compensation voltage signal, offsets a load interference component in the initial voltage signal, and extracts seepage pressure. The application realizes physical domain decoupling of seepage pressure and structure stress from a sensing source by matching physical symmetry of a sensing topology and medium modulus, eliminates zero point drift caused by dam creep, and ensures authenticity of seepage monitoring under a high hydrostatic pressure environment.

Description

Technical Field

[0001] This invention belongs to the field of intelligent sensor technology, and in particular relates to a sensing system for extracting seepage pressure within a dam. Background Technology

[0002] Currently, seepage pressure monitoring is a key indicator for evaluating the safe operation of dams. Seepage pressure is collected by sensors embedded inside the dam body. The mainstream technology uses sensors with rigid protective structures. However, due to the influence of the complex physical field deep within the dam, the mechanical load generated by the dam's own weight and tectonic movement is transmitted to the internal sensitive chip through the sensor housing, generating interference components with the same dimensions as the seepage pressure being measured. As the dam ages, concrete creep and rockfill settlement induce micro-deformation in the sensor housing, forming parasitic stress. This stress acts on the sensitive components, producing zero-point drift that is difficult to eliminate, interfering with the evaluation of the true seepage state of the dam.

[0003] To suppress stress interference, the thickness of the sensor housing is usually increased. This reduces the signal transmission sensitivity and produces time lag and nonlinear hysteresis. At the same time, external data fitting schemes lack environmental stress reference sources and cannot isolate the signal components caused by structural creep in situ, causing the seepage data to deviate from the true physical state. In addition to enhancing the rigidity of the hardware housing to shield interference, the industry has tried to use internal compensation logic to correct it. For example, Chinese invention patent application with publication number CN118961037A discloses a vibrating wire piezometer for reservoir dam safety monitoring, which uses a temperature-induced telescopic rod to adjust the position of the vibrating wire end to compensate for the changes in the length and tension of the vibrating wire caused by temperature changes.

[0004] Therefore, the technical problem to be solved by this invention is how to design a physical sensing structure with load self-decoupling capability, realize active offsetting of structural stress components in the physical sensing layer, thereby eliminating parasitic interference caused by dam creep and obtaining high-fidelity seepage pressure data. Summary of the Invention

[0005] The present invention aims to solve the problem that the physical superposition of structural load and fluid pressure at the sensor sensing end makes it impossible to isolate parasitic interference signals caused by dam creep.

[0006] In this technical solution, a sensing system for extracting seepage pressure within a dam includes: The perception framework module contains a first perception space and a second perception space. The primary sensing module is located within the first sensing space and is connected to the external seepage channel via a flexible connecting component. The compensation sensing module is located within the second sensing space; The signal decoupling processing module is electrically connected to both the primary sensing module and the compensation sensing module. The primary and compensation sensing modules are centrally symmetrically distributed within the sensing frame module's spatial topology, and are connected in parallel to the same constant current drive source. The second sensing space is a fully enclosed cavity structure filled with a pressure-transmitting medium with controllable bulk modulus, ensuring that the stress source sensed by the compensation sensing module is limited to the surface elastic strain transmitted from the dam structure load to the sensing frame module. The primary sensing module acquires the initial voltage signal characterizing the superimposed response of seepage pressure and dam structure load. The compensation sensing module acquires the compensation voltage signal characterizing the dam structure load response. Based on the common-mode potential correlation between the initial and compensation voltage signals, the signal decoupling processing module cancels the parasitic interference component generated by the dam structure load in the initial voltage signal and extracts the target pressure characteristic data corresponding to the seepage pressure.

[0007] Preferably, the external part of the sensing frame module is provided with a stress homogenization coating layer; the elastic modulus of the stress homogenization coating layer is lower than that of the sensing frame module, which is used to convert the anisotropic shear force inside the dam body into a uniformly distributed pressure acting on the surface of the sensing frame module, so that the primary sensing module and the compensation sensing module are in the same background stress field.

[0008] Preferably, the stress homogenization coating layer utilizes the properties of a low elastic modulus medium to transform the point contact force transmission between the sensing frame module and the dam concrete into surface contact stress transmission, thereby eliminating the asymmetric parasitic strain interference caused by the non-uniform settlement of the dam and improving the signal extraction accuracy of the signal decoupling processing module under static high pressure conditions.

[0009] Preferably, the primary sensing module and the compensation sensing module are arranged symmetrically back-to-back within the sensing framework module; the bridge input terminals of the primary sensing module and the compensation sensing module are connected in parallel to the constant current drive source to achieve synchronization of the initial voltage signal and the compensation voltage signal at the zero-point temperature drift at the physical layer.

[0010] Preferably, a medium screening module is provided outside the sensing frame module, which covers the pressure inlet of the primary sensing module; the medium screening module blocks solid particles from entering the first sensing space, so that the primary sensing module only responds to the hydrostatic pressure and structural stress, and eliminates solid point loads.

[0011] Preferably, the signal decoupling processing module monitors the temporal fluctuation pattern of the compensation voltage signal to obtain the material stress creep characteristics generated by the sensing frame module during the dam's operating cycle, and corrects the zero-point offset of the initial voltage signal based on the material stress creep characteristics to achieve self-closed-loop calibration of the sensing system.

[0012] Preferably, the sensing frame module has a stress coupling component inside, and both the primary sensing module and the compensation sensing module are fixed on the stress coupling component; the external deformation received by the sensing frame module is synchronously transmitted to the two sensing modules through the stress coupling component to form a common-mode stress signal that can be differentially eliminated.

[0013] Preferably, the sensing frame module is made of a high-rigidity alloy; the axial stiffness of the pressure-sensing component of the primary sensing module is less than 10 N / mm, and the axial stiffness is less than 1% of the equivalent stiffness of the sensing frame module, so that the first sensing space can sense seepage pressure fluctuations of more than 10 Pa and ensure the response sensitivity of the initial voltage signal.

[0014] Preferably, the sensing system also includes a digital transmitter bus module; the digital transmitter bus module converts the target pressure characteristic data output by the signal decoupling processing module into a digital signal conforming to the MODBUS communication protocol, so as to output digital monitoring information characterizing the dam seepage line height and the internal pressure state of the dam body.

[0015] Compared with existing technologies, the sensing system for extracting seepage pressure within dams in this invention has the following advantages: Firstly, in the sensing system for extracting seepage pressure within the dam, the system constructs a geometrically symmetrical measurement cavity and reference cavity inside a metal cylindrical shell, and, in conjunction with a load balancing layer surrounding the outer periphery of the shell, provides a physical-level in-situ stress counterbalancing mechanism. This mechanism utilizes the homogeneous force characteristics of the first and second sensitive chips under the same physical envelope to convert the creep load generated by the dam structure over time into a common-mode signal in the differential bridge circuit for cancellation. This signal purification method achieved through physical topology avoids dependence on the complex finite element model of the dam body, ensuring that the seepage pressure extraction process does not experience zero-point drift as the dam's service life increases, thereby guaranteeing the physical authenticity of the monitoring data during long-term operation.

[0016] Secondly, the load balancing layer, through its low elastic modulus medium properties, transforms the complex anisotropic shear stress inside the dam body into quasi-hydrostatic pressure acting on the shell surface. This physical transformation process ensures a high degree of consistency between the background stress field sensed by the measuring cavity and the reference cavity, thereby eliminating asymmetric interference caused by the force directionality of the dam body at the source of signal generation. This reconstruction of the load transmission path makes the sensing system more adaptable to the burial angle and uneven settlement, reducing the accuracy requirements of engineering installation while improving the signal-to-noise ratio of pressure signal extraction under complex working conditions.

[0017] Thirdly, the heterogeneous sensing logic between the measurement chamber and the reference chamber achieves physical domain separation of fluid pressure and solid stress through the medium screening effect of the water-permeable filter membrane and the structural isolation effect of the fully enclosed chamber. Since the first sensitive chip directly responds to the combined load of fluid and structure, while the second sensitive chip only tracks the changing characteristics of structural load, the system uses the potential cancellation mechanism of the simulated front end to strip away the mechanical deformation component parasitic in the pressure signal in real time. This method changes the traditional sensor solution that relies on increasing the rigidity of the shell to shield interference. Under the premise of maintaining the high sensitivity response characteristics of the sensor, it solves the industry problem of the deformation of the shell surface interfering with the measurement accuracy under high hydrostatic pressure. Attached Figure Description

[0018] Figure 1 This invention relates to the system physical topology and signal decoupling principle diagram; Figure 2 This invention relates to the adaptive compensation logic and operating state transition diagram. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0020] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0022] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0023] Example 1: This example relates to a sensing system for extracting seepage pressure within a dam, comprising: The perception framework module contains a first perception space and a second perception space. The primary sensing module is located within the first sensing space and is connected to the external seepage channel via a flexible connecting component. The compensation sensing module is located within the second sensing space; The signal decoupling processing module is electrically connected to both the primary sensing module and the compensation sensing module. The primary and compensation sensing modules are centrally symmetrically distributed within the sensing frame module's spatial topology, and are connected in parallel to the same constant current drive source. The second sensing space is a fully enclosed cavity structure filled with a pressure-transmitting medium with controllable bulk modulus, ensuring that the stress source sensed by the compensation sensing module is limited to the surface elastic strain transmitted from the dam structure load to the sensing frame module. The primary sensing module acquires the initial voltage signal characterizing the superimposed response of seepage pressure and dam structure load. The compensation sensing module acquires the compensation voltage signal characterizing the dam structure load response. Based on the common-mode potential correlation between the initial and compensation voltage signals, the signal decoupling processing module cancels the parasitic interference component generated by the dam structure load in the initial voltage signal and extracts the target pressure characteristic data corresponding to the seepage pressure.

[0024] The sensing frame module described in this embodiment has a stress homogenization coating layer on its exterior. The elastic modulus of the stress homogenization coating layer is lower than that of the sensing frame module. It is used to convert the anisotropic shear force inside the dam body into a uniformly distributed pressure acting on the surface of the sensing frame module, so that the primary sensing module and the compensation sensing module are in the same background stress field.

[0025] The stress homogenization coating layer described in this embodiment utilizes the properties of a low elastic modulus medium to transform the point contact force transmission between the sensing frame module and the dam concrete into surface contact stress transmission. This is used to eliminate the asymmetric parasitic strain interference caused by the non-uniform settlement of the dam body and improve the signal extraction accuracy of the signal decoupling processing module under static high pressure conditions.

[0026] In this embodiment, the primary sensing module and the compensation sensing module are arranged symmetrically back-to-back within the sensing framework module; the bridge input terminals of the primary sensing module and the compensation sensing module are connected in parallel to the constant current drive source to achieve synchronization of the initial voltage signal and the compensation voltage signal at the zero-point temperature drift at the physical layer.

[0027] The sensing frame module described in this embodiment is externally equipped with a media filtering module, which covers the pressure inlet of the primary sensing module. The media filtering module blocks solid particles from entering the first sensing space, so that the primary sensing module only responds to hydrostatic pressure and structural stress, and eliminates solid point loads.

[0028] The signal decoupling processing module described in this embodiment monitors the temporal fluctuation pattern of the compensation voltage signal to obtain the material stress creep characteristics generated by the sensing frame module during the dam's operating cycle, and corrects the zero-point offset of the initial voltage signal based on the material stress creep characteristics to achieve self-closed-loop calibration of the sensing system.

[0029] The sensing frame module described in this embodiment is equipped with a stress coupling component. The primary sensing module and the compensation sensing module are both fixed on the stress coupling component. The external deformation received by the sensing frame module is synchronously transmitted to the two sensing modules through the stress coupling component, forming a common-mode stress signal that can be differentially eliminated.

[0030] The sensing frame module described in this embodiment is made of a high-rigidity alloy; the axial stiffness of the pressure-sensing component of the primary sensing module is less than 10 N / mm, and this axial stiffness is less than 1% of the equivalent stiffness of the sensing frame module, so that the first sensing space can sense seepage pressure fluctuations of more than 10 Pa and ensure the response sensitivity of the initial voltage signal.

[0031] The sensing system described in this embodiment also includes a digital transmitter bus module; the digital transmitter bus module converts the target pressure characteristic data output by the signal decoupling processing module into a digital signal conforming to the MODBUS communication protocol, so as to output digital monitoring information characterizing the dam seepage line height and the internal pressure state of the dam body.

[0032] Example 2: In this example, during deep-hole seepage monitoring of a large concrete double-curvature arch dam with an operating water level difference exceeding 100 meters, the dam body continuously generates anisotropic non-uniform shear stress caused by alternating self-weight loads and long-term concrete shrinkage and creep. The elastic deformation of the shell caused by this structural load is directly transmitted to the rigid metal shell of the pre-embedded monitoring instrument, forming a pseudo-pressure signal with the same dimension as the hydrostatic pressure of the fluid being measured. Conventional sensor systems cannot distinguish between the creep stress of the solid phase medium and the seepage pressure of the liquid phase medium at the physical sensing source. The output data exhibits nonlinear zero-point drift as the service life extends. The sensing system used for extracting seepage pressure within the dam is deployed in this non-uniform background stress field. A stress homogenizing coating layer, which is wrapped around the sensing frame module and has an elastic modulus lower than that of the sensing frame module, transmits the irregular point contact force and anisotropic stress generated by the dam concrete. The shear force is converted into a uniformly distributed pressure acting on the surface of the sensing frame module, so that the first and second sensing spaces inside the system are in a homogenized background stress field, forming a surface contact transformation of the stress transmission path. The stress homogenization coating layer wrapped around the sensing frame module is made of modified polyurethane elastomer with a Shore hardness of 60A to 85A. It is manufactured by isostatic pressing vulcanization molding process to attach the modified polyurethane elastomer to the metal outer surface of the sensing frame module. The bonding strength between the coating layer and the sensing frame module interface is controlled to be greater than 5MPa. It can withstand the anisotropic shear deformation inside the dam body. The modified polyurethane elastomer undergoes local shear deformation to absorb the irregular point contact load from the outside. It relies on the bonding strength of more than 5MPa to resist the peeling of the elastomer layers under high hydrostatic pressure, so that the residual stress state of the contact interface is redistributed into a uniformly distributed pressure acting on the surface of the sensing frame module.

[0033] The primary sensing module and the compensation sensing module, fixed to the stress coupling component inside the sensing frame module, synchronously sense the stress state of the system under a homogenized common-mode background load. The medium screening module covered by the pressure inlet of the primary sensing module blocks external solid particles and introduces the hydrostatic pressure of the fluid in the external seepage channel through a flexible connecting component. The force on the primary sensing module is superimposed with the hydrostatic pressure and the dam structure load, and an initial voltage signal characterizing this composite response is obtained. The compensation sensing module, which is centrally symmetrically distributed with the primary sensing module in the spatial topology of the sensing frame module, is located in a fully enclosed second sensing space. The second sensing space is filled with a pressure-transmitting medium with a matching bulk modulus. The physical isolation mechanism limits the stress source sensed by the compensation sensing module to the elastic strain of the shell of the sensing frame module transmitted from the dam structure load, and obtains a compensation voltage signal that only characterizes the response of the dam structure load. The bridge input terminals of the primary sensing module and the compensation sensing module are connected in parallel to the same constant current drive source. The system realizes zero-point temperature drift synchronization of the initial voltage signal and the compensation voltage signal at the physical hardware level. In terms of specific configuration, both the primary sensing module and the compensation sensing module have The circuit integrates a full-bridge Wheatstone circuit composed of four identical silicon-based piezoresistive components. Two independent piezoresistive chips are directly connected in parallel at the hardware substrate level, with their positive and negative power terminals connected via symmetrical, equal-length copper traces. They are both connected to the same drive source network with microampere-level constant current and voltage regulation output characteristics. This physical topology ensures that the piezoresistive bridges in the two test chambers obtain completely consistent excitation current and heat dissipation physical boundaries, fixing the common-mode consistency of zero-point temperature drift at the hardware signal origin. A corrugated metal isolation membrane is processed on the inner wall of the second sensing space corresponding to the sensing frame module. The sheet, with a thickness between 0.05 mm and 0.2 mm, encapsulates the pressure transmission medium using a vacuum degassing process to degas the mixture of methyl silicone oil and hollow glass microspheres under a vacuum of better than 10 Pa. The degassed mixture is then filled into the second sensing space with a pre-tightening reference pressure of 0.5 MPa to 1.0 MPa and physically sealed. The corrugated metal isolation diaphragm follows the sensing frame module and undergoes flexural displacement due to the surface elastic strain. The degassed mixture, which eliminates the interference of microbubbles, directly converts the surface volume change of the sensing frame module into the hydrostatic pressure change acting on the surface of the compensation sensing module.

[0034] The signal decoupling processing module receives the initial voltage signal and the compensation voltage signal. Based on the common-mode potential correlation formed by the two under the same physical envelope and the same constant current driving source, it monitors the temporal fluctuation law of the compensation voltage signal. It extracts the material stress creep characteristics generated by the sensing frame module with the dam's operating cycle. The above creep characteristics are used as a counterbalancing reference source to cancel the interference component generated by the dam structure load in the initial voltage signal. The pressure sensing component of the primary sensing module senses the seepage pressure fluctuation of more than 10 Pa in the first sensing space under the mechanical limitation that the axial stiffness is less than 10 N / mm and the axial stiffness is less than 1% of the equivalent stiffness of the sensing frame module. The digital transmission bus module converts the target pressure characteristic data after stripping the structural stress interference into a digital signal conforming to the MODBUS communication protocol and outputs it. The system relies on the central symmetric physical distribution of the sensing topology and the isolation and screening mechanism of the medium to realize the unidirectional decoupling of seepage pressure and dam structure stress at the physical sensing node and eliminate the zero-point offset difference caused by structural creep.

[0035] Example 3: In this example, under the servo-hydraulic composite loading condition of a deep borehole monitoring environment for a double-curvature arch dam with a simulated water level difference exceeding 100 meters, data on the coupling effect of anisotropic shear creep stress continuously generated in the dam concrete and high-pressure seepage were acquired. A triaxial independently controlled rock mechanics testing system was used as the physical experimental platform. This testing system has a static confining pressure loading capacity of 50 MPa and a dynamic pore water pressure injection channel with an accuracy of 0.01 MPa. The stress field and seepage field inside the dam were reproduced outside the sensing system, and the axial deviatoric stress of the loading system was set. Using the gradual gradient as the evaluation criterion, the deviatoric stress loading rate needs to balance the fidelity of the dynamic creep evolution response and the stress equilibrium time inside the system. When the displacement sensor of the external loading mechanism detects that the deformation rate of the sample is greater than the preset threshold, the deviatoric stress loading rate is reduced to avoid the hysteresis rheological error of the sensing system. The deviatoric stress loading rate is selected as 0.5 MPa / min. At the same time, Gaussian white noise with a signal-to-noise ratio of 20 dB and power frequency pressure pulsation with a frequency of 50 Hz are superimposed in the pore water pressure injection channel to simulate water hammer interference and electromagnetic background noise at the engineering site.

[0036] A single-cavity piezoresistive sensor without a compensation sensing module and a second sensing space was selected as the first comparison group. A sensing system with a stress homogenization coating layer, whose elastic modulus is equal to that of the sensing frame module, was selected as the second comparison group. A sensing system possessing all the technical features of this invention was selected as the test group. The above three test groups were embedded in the center of plain concrete specimens and placed in a sealed pressure chamber. The initial hydrostatic pressure was set to 10.05 MPa and kept constant. A structural deviatoric stress ranging from 0 MPa to 20 MPa in 5 MPa increments was applied by a triaxial actuator. The output pressure data of the first comparison group deviated from the reference water pressure by 1.21 MPa when a deviatoric stress of 5 MPa was applied, and showed a positive zero-point drift as the deviatoric stress increased. The output deviation of the second comparison group remained within 0.28 MPa when the deviatoric stress was below 10 MPa. When the deviatoric stress crossed the critical point of 15 MPa, the equal modulus coating layer could not absorb the circumferential anisotropic shear stress, the sensing frame module underwent nonlinear warping, the common mode stress field of the primary sensing module and the compensation sensing module was destroyed, and the pressure characteristic data output by the signal decoupling processing module changed abruptly and produced a distortion of 2.53 MPa.

[0037] During the full-gradient deviatoric stress loading process from 0MPa to 20MPa, the stress homogenization coating layer deformed due to its physical property of having an elastic modulus lower than that of the sensing frame module. It absorbed and converted the circumferential anisotropic shear force into a uniformly distributed pressure. The compensation sensing module captured the common-mode structural elastic strain consistent with the primary sensing module in the fully enclosed second sensing space. The signal decoupling processing module completed differential calculation based on the common-mode potential correlation between the initial voltage signal and the compensation voltage signal, filtering out the power frequency pulsation and Gaussian white noise superimposed on the 10.05MPa hydrostatic pressure. Under the interference of 20MPa deviatoric stress, the target pressure characteristic data output by the test group remained within the range of 9.98MPa to 10.07MPa, with a maximum full-scale error of no more than 0.5%. The test data confirmed that the physical space center-symmetric topology and the medium isolation mechanism have the ability to decouple multi-physics coupling interference. The sensing system cut off the signal aliasing path of solid medium creep stress and fluid seepage pressure by means of the isolation action of the front-end sensing component.

[0038] Example 4: In this example, before deploying the sensing system at the high-stress monitoring point in the deep-buried environment of the dam body, a micro-force loading device with a displacement resolution better than 0.1μm is used to determine the axial stiffness of the pressure-sensing component in the primary sensing module. The measurement process includes applying a load sequence of 0.1N to 1.0N along the force axis of the pressure-sensing component and obtaining the corresponding elastic displacement; applying a pressure gradient of 0.1MPa to 20.0MPa to the sensing frame module using a pressure loading device, and calculating the displacement change rate of the sensing frame module under pressure response to determine the equivalent stiffness. When the axial stiffness of the pressure-sensing component Equivalent stiffness of the perception framework module Satisfying the relation And axial stiffness When the load is less than 10.0 N / mm, the sensing frame module provides physical shielding against the elastic deformation of the shell caused by external structural loads.

[0039] For seepage fluid environments with varying sand content or mineralization, the system utilizes the component adjustment mechanism of the pressure-transmitting medium to match physical properties, selecting a dynamic viscosity of 100 mm⁻¹. 2 / s to 500mm 2 Using methyl silicone oil as the matrix, 3.5% (by mass) of hollow glass microspheres are introduced. These microspheres have an average particle size of 20μm to 50μm and a pressure resistance of not less than 40MPa. The bulk modulus Bm of the pressure-transmitting medium is calibrated using a high-pressure circulating pump under a temperature control accuracy of 0.1℃. By adjusting the addition ratio of hollow glass microspheres, the bulk modulus Bm of the pressure-transmitting medium is made to satisfy the relationship 0.95Bf≤Bm≤1.05Bf with the bulk modulus Bf of the external seepage fluid. At this point, the pressure transmission path formed inside the fully enclosed second sensing space is connected to the first sensing space. The pressure transmission path is aligned in terms of physical response characteristics. The specific bulk modulus matching mechanism is that the equivalent bulk modulus of the deep pore seepage fluid in the dam is lower than that of pure water due to dissolved gas and carrying microbubbles. The matrix methyl silicone oil undergoes nonlinear volume compression under high pressure pre-tightening conditions. At this time, by controlling the mass percentage of hollow glass microspheres with fixed compressive yield limit, the elastic deformation of the surface of the microspheres is used to compensate for the stiffness hardening of the silicone oil after pressure. Thus, the apparent bulk modulus of the mixed medium in the working pressure range is accurately adjusted to be consistent with the actual equivalent bulk modulus of the gas-containing seepage fluid.

[0040] The signal decoupling processing module processes the acquired initial voltage signal. With compensation voltage signal Discretization is performed first, aligning the initial voltage signal. With compensation voltage signal The sampling time point is determined to eliminate phase lag caused by the hardware channel; the common-mode gain factor is calculated. The common-mode gain factor The value is obtained by using the initial voltage signal under zero hydrostatic pressure. With compensation voltage signal The ratio is determined using this common-mode gain factor. With compensation voltage signal The product generation of the modified operator for the material creep characteristics of the perception framework module. Based on this, a differential operational circuit is used to obtain the initial voltage signal. Middle removal correction operator The target pressure characteristic data, stripped of structural load interference, is extracted. In the specific execution path of the differential operation, the signal decoupling processing module extracts the extremely low-frequency baseline fluctuation in the compensation voltage signal through a low-pass digital filter with a cutoff frequency of 0.01Hz. This fluctuation is then characterized as a slow creep component that evolves with the age of the dam and included in the correction operator Screen. The operation logic subtracts this extremely low-frequency baseline fluctuation from the real-time captured compensation voltage signal, separating the random structural strain component caused by the dynamic alternating load of the dam. Finally, the differential core circuit, according to the weight ratio based on the common-mode gain factor, synchronously subtracts the stripped extremely low-frequency creep component and random strain component from the initial voltage signal, completing the mathematical domain isolation of structural load interference across the entire frequency band. The above calibration procedure and decoupling method establish a parameterized mapping relationship based on physical topological symmetry, enabling the sensing system to maintain the stability of the measurement benchmark under the anisotropic shear force and long-term creep stress interference generated during the service life of concrete. The target pressure characteristic data output by the system is converted into a standard digital signal through the digital transmitter bus module, realizing in-situ offsetting of strain interference during the seepage pressure extraction process.

[0041] Example 5: In this example, during the balance calibration before the pre-installation of the sensing system, it is necessary to establish a mapping between the system's physical zero point and electrical reference. The assembled system is placed horizontally in a pressure-stabilized test chamber, and the constant current drive source is turned on to bring the primary sensing module and the compensation sensing module to thermal equilibrium. A reference pressure source with a pressure resolution better than 10 Pa is used to monitor the internal pressure of the test chamber and maintain it at the local atmospheric pressure. The signal decoupling processing module synchronously acquires the initial voltage signal. With compensation voltage signal And calculate the initial bias difference between the two. The signal decoupling processing module stores the bias difference as a static compensation operator to eliminate the local physical performance differences between the two piezoresistive chips during the manufacturing stage. After the system is transported to the dam site and fixed in the installation position, the initial voltage change value introduced by the sensor's self-weight and installation prestress is recorded again before concrete pouring. This change value is injected into the static storage unit of the signal decoupling processing module as an environmental reference load. The shell elastic deformation caused by the dam structure load is incrementally calculated on the basis of this reference load.

[0042] When the system faces dynamic seepage response conditions caused by rapid changes in dam water level, the signal decoupling processing module initiates a sampling phase synchronization alignment procedure to resolve phase lag caused by distributed parameters in the signal transmission link. The sampling frequency within this module is set to 1000Hz and the timestamp accuracy error is no higher than 1. The module monitors the initial voltage signal. With compensation voltage signal The high-frequency characteristic ripple in the sequence is used as a synchronous anchor point to calculate the initial voltage signal. With compensation voltage signal Time delay factor between The signal decoupling processing module uses a digital shift operator to process the compensation voltage signal. Perform hysteresis compensation with a step size of 1ms to make the initial voltage signal... With compensation voltage signal Achieving linear alignment of physical field responses on the same time scale, the signal decoupling processing module extracts target pressure characteristic data after stripping the load interference of the dam structure during differential offsetting. The digital pressure signal output by the system corresponds to the real-time change state of transient seepage fluctuations. At this time, the time delay factor τ mainly comes from the millisecond-level fluid dynamic damping hysteresis generated when external water pressure permeates into the first sensing space through the flexible connecting component and filter membrane, rather than the extremely short-term solid mechanical stress wave transmission difference. The 1000Hz sampling frequency and 1ms compensation step size precisely cover the inherent low-frequency fluid dynamic hysteresis range of fluid transmission in porous media. By locking the low-frequency water hammer pulsation envelope characteristics through microsecond-level timestamps, the system can accurately remove the overall hysteresis time of fluid pressure transmission from the electrical signal sequence, thereby establishing the basis for synchronization with the slowly changing structural elastic strain on the millisecond scale.

[0043] Example 6: In this example, during the external stress matching calibration of the sensing system used for deeply buried monitoring points, it is necessary to determine the geometric thickness of the stress homogenization coating layer. To balance shear force conversion efficiency and pressure transmission fidelity, the outer diameter of the sensing frame module was obtained through a combination of numerical simulation and physical experiments. and its material elastic modulus Selecting a thickness gradient as to The coated layer samples were subjected to triaxial independent controlled loading tests to obtain the uniform pressure deviation value on the inner surface of the coated layer. With thickness The nonlinear evolution curve; when the thickness When the layer is increased, the stress homogenization coating layer's ability to absorb and convert anisotropic shear stress is enhanced, making the radial pressure acting on the boundary between the first and second sensing spaces tend to be consistent. A selection that satisfies... %and The physical parameters are used as the standard values ​​for system encapsulation. The encapsulation process on the outer surface of the sensing frame module transforms the concentrated load generated by external solid-phase creep into a uniform surface contact pressure field. The determination of the geometric proportions and error thresholds of the encapsulation layer is based on the finite element iterative analysis of cylindrical elastic contact mechanics. An extreme asymmetric nodal shear force field is applied to the outer surface of the sensing frame in the simulation model for scanning simulation. The calculation results confirm that when the thickness of the polyurethane encapsulation layer is greater than d... c Reaching outer diameter R fAt 0.15 times the critical point, the circumferential stress redistribution effect caused by large material deformation undergoes abrupt change, causing the non-uniform stress concentration rate transmitted to the inner boundary of the metal to decrease exponentially. At this point, the radial stress difference at various points on the inner surface is sufficiently suppressed. Using this mechanical derivation as the encapsulation boundary, the uniform pressure deviation σ of the system under extreme stress conditions can be guaranteed. err It converges stably within the set tolerance of 1.0%.

[0044] When the sensing system operates in the dam's internal duct environment with a temperature difference exceeding 40.0℃, to compensate for the thermal expansion coefficient mismatch between the pressure-transmitting medium and the sensing frame module, an offline calibration program for the medium's thermophysical steady state and zero-point reference is initiated, utilizing a volume change rate resolution better than 10. -6 / The dilatometer measures the volumetric expansion coefficient of the pressure-transmitting medium. Simultaneously acquire the volume shrinkage coefficient of the material in the sensing framework module. By adjusting the molecular weight distribution of methyl silicone oil in the pressure-transmitting medium and the filling density of hollow glass microspheres, the pressure-transmitting medium and the sensing frame module can meet the zero-drift heat compensation criterion, i.e., within an ambient temperature range of 5.0℃ to 45.0℃. Within the specified range, the volume change of the pressure-transmitting medium due to temperature fluctuations offsets the elastic reduction in the volume of the fully enclosed second sensing space. The signal decoupling processing module acquires the compensation voltage signal during this process. The temperature drift component is limited to within 0.1% of the full scale. The system establishes a thermal stress equilibrium state compatible with the sensing topology at the material property level and eliminates static pressure deviation data caused by ambient temperature fluctuations.

[0045] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A sensing system for extracting seepage pressure within a dam, characterized in that, include: The perception framework module contains a first perception space and a second perception space. The primary sensing module is located within the first sensing space and is connected to the external seepage channel via a flexible connecting component. The compensation sensing module is located within the second sensing space; The signal decoupling processing module is electrically connected to both the primary sensing module and the compensation sensing module. The primary sensing module and the compensation sensing module are centrally symmetrically distributed in the spatial topology within the sensing frame module, and are connected in parallel to the same constant current drive source. The second sensing space is a fully enclosed cavity structure filled with a pressure-transmitting medium with controllable bulk modulus, so that the stress source sensed by the compensation sensing module is limited to the surface elastic strain transmitted from the dam structure load to the sensing frame module. The primary sensing module acquires the initial voltage signal characterizing the superimposed response of seepage pressure and dam structure load. The compensation sensing module acquires the compensation voltage signal characterizing the load response of the dam structure; the signal decoupling processing module, based on the common-mode potential correlation between the initial voltage signal and the compensation voltage signal, cancels the parasitic interference component generated by the dam structure load in the initial voltage signal and extracts the target pressure characteristic data corresponding to the seepage pressure.

2. The sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The sensing frame module is provided with a stress homogenization coating layer on its exterior. The elastic modulus of the stress homogenization coating layer is lower than that of the sensing frame module. It is used to convert the anisotropic shear force inside the dam body into a uniformly distributed pressure acting on the surface of the sensing frame module, so that the primary sensing module and the compensation sensing module are in the same background stress field.

3. The sensing system for extracting seepage pressure within a dam according to claim 2, characterized in that: The stress homogenization coating layer utilizes the properties of a low elastic modulus medium to transform the point contact force transmission between the sensing frame module and the dam concrete into surface contact stress transmission, thereby eliminating the asymmetric parasitic strain interference caused by the non-uniform settlement of the dam and improving the signal extraction accuracy of the signal decoupling processing module under static high pressure conditions.

4. The sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The primary sensing module and the compensation sensing module are arranged symmetrically back to back within the sensing framework module; the bridge input terminals of the primary sensing module and the compensation sensing module are connected in parallel to the constant current drive source to realize the synchronization of the initial voltage signal and the compensation voltage signal at the physical layer zero-point temperature drift.

5. The sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The sensing frame module is equipped with a media screening module on its exterior, which covers the pressure inlet of the primary sensing module. The media screening module blocks solid particles from entering the first sensing space, so that the primary sensing module only responds to the hydrostatic pressure of the fluid and the structural stress, and eliminates solid point loads.

6. The sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The signal decoupling processing module monitors the temporal fluctuation pattern of the compensation voltage signal to obtain the material stress creep characteristics generated by the sensing frame module during the dam's operating cycle, and corrects the zero-point offset of the initial voltage signal based on the material stress creep characteristics to achieve self-closed-loop calibration of the sensing system.

7. The sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The sensing frame module has a stress coupling component inside, and the primary sensing module and the compensation sensing module are both fixed on the stress coupling component. The external deformation received by the sensing frame module is synchronously transmitted to the two sensing modules through the stress coupling component to form a common-mode stress signal that can be differentially eliminated.

8. The sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The sensing frame module is made of a high-rigidity alloy; the axial stiffness of the pressure-sensing component of the primary sensing module is less than 10 N / mm, and this axial stiffness is less than 1% of the equivalent stiffness of the sensing frame module, so that the first sensing space can sense seepage pressure fluctuations of more than 10 Pa and ensure the response sensitivity of the initial voltage signal.

9. A sensing system for extracting seepage pressure within a dam according to claim 1, characterized in that: The sensing system also includes a digital transmitter bus module; the digital transmitter bus module converts the target pressure characteristic data output by the signal decoupling processing module into digital signals that conform to the MODBUS communication protocol, so as to output digital monitoring information characterizing the dam phreatic line height and the internal pressure state of the dam body.

Images