Pavement structure interlayer bonding state field test method based on vibration spectrum analysis

Abstract

The invention discloses a pavement structure interlayer bonding state field test method based on vibration spectrum analysis, and relates to the technical field of traffic infrastructure detection, and the method comprises the following steps: at the beginning stage of pavement structure interlayer bonding state field test, carrying out energy gradual rise control on excitation input of an excitation device, and continuously changing the excitation intensity along the time direction and forming an excitation energy evolution track. According to the method, an excitation energy evolution track is established through energy gradual increase control, overall resonance caused by sudden energy increase is avoided, interlayer slippage spectrum features are extracted, and accurate recognition of the local bonding state is achieved; and through phase transfer analysis and breathing type excitation adjustment, interlayer micro-motion can be continuously distinguished, a stable judgment base line is constructed, and dynamic identification and high-sensitivity tracking of the critical viscosity loss state are achieved.

Description

Technical Field

[0001] This invention relates to the field of transportation infrastructure testing technology, specifically to a field testing method for the interlayer bonding state of pavement structures based on vibration spectrum analysis. Background Technology

[0002] Field testing of interlayer bonding status of pavement structures based on vibration spectrum analysis refers to deploying an intelligent sensing system with acquisition and computing capabilities at the road site. A controllable vibration input is applied to the pavement through an excitation device, and vibration response signals at different locations on the pavement are collected simultaneously by an array of acceleration, velocity, and displacement sensors. After noise reduction, segmentation, and time-scale alignment at the edge side, the sensing nodes extract frequency domain features to form a spectral fingerprint reflecting the coordinated vibration relationship of each structural layer. This spectral fingerprint is then compared with a preset intact bonding reference feature to identify frequency domain anomalies related to interlayer slippage, delamination, and weak bonding, such as resonance peak position shift, peak energy distribution change, and phase consistency failure. Thus, the field determination of the interlayer bonding status of structural layers such as the surface layer and base layer can be achieved without damaging the pavement structure, and the sensing system outputs traceable test records and judgment results.

[0003] The existing technology has the following shortcomings: In existing technologies, when conducting field tests on the interlayer bonding state of pavement structures based on vibration spectrum analysis, the overall vibration response of the structural layers is typically obtained through excitation input, and spectral features are extracted for bonding state determination. However, in actual testing, when the excitation energy released by the excitation device suddenly increases within a short period, each layer of the pavement structure is driven by a high amplitude. The weak relative displacements that already exist between the structural layers are masked by the strong overall vibration response, making it difficult to effectively separate these displacement features from the acquired signals. At the frequency domain level, this manifests as a high concentration of spectral energy towards a single dominant frequency, with the characteristic frequency bands originally used to reflect the relative motion between layers being compressed or even disappearing, resulting in a phenomenon of instantaneous collapse of the spectral peak. As a result, the judgment logic based on the stability of the dominant peak and the energy concentration in existing technologies is prone to misjudging the interface of structural layers that are already in a critical state of debonding as a state of good bonding, thus masking the true risk of bonding deterioration. In the subsequent service phase of the road, when heavy traffic loads are repeatedly applied to the road section, due to insufficient interlayer bonding capacity, shear stress continues to accumulate, eventually leading to overall shear slip between structural layers, causing severe damage to the pavement structure.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a field testing method for the interlayer bonding state of pavement structures based on vibration spectrum analysis, so as to solve the problems in the background art mentioned above.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a field testing method for the interlayer bonding state of pavement structures based on vibration spectrum analysis, comprising the following steps: In the initial stage of the field test of the interlayer bonding state of the pavement structure, the energy of the excitation input of the excitation device is gradually controlled to make the excitation intensity change continuously along the time direction and form the excitation energy evolution trajectory, which is used to establish the initial vibration response benchmark of the interlayer bonding interface of the pavement structure. Based on the excitation energy evolution trajectory, the collected road vibration response signals are expanded and compared in the same time sequence. The subtle vibration difference components generated by the change of excitation energy are separated in the overall vibration response, and spectral difference clues reflecting the relative slip change between the road structure layers are generated. Phase shift analysis is introduced along the time axis along the spectral difference clues, so that the relative motion between pavement structure layers is gradually revealed in the form of continuous phase shift, and a debonding indicator is formed during the phase shift process to characterize the debonding trend between layers. Based on the debonding pointing mark, the excitation energy evolution trajectory is adjusted in reverse beat, so that the overall high-energy vibration response gradually weakens along the time sequence, and the vibration characteristics related to the relative displacement between pavement structure layers are enhanced simultaneously, and a stable judgment baseline for bond state determination is constructed. Based on the judgment baseline-triggered reverse breathing vibration regulation, the periodic convergence and expansion of the excitation energy makes the micro-motion differences between pavement structure layers remain distinguishable during the test, thereby achieving dynamic control and identification of the critical de-adhesion state.

[0007] Preferably, the formation process of the excitation energy evolution trajectory is as follows: In the initial stage of the gradual energy increase construction phase, the excitation device is pre-driven according to the set energy increase law, so that the excitation input is gradually applied to the surface of the road structure in the form of low amplitude and low frequency during the initial time period. When the energy gradually increases into the middle stage, the output of the excitation device is finely adjusted so that the excitation energy changes smoothly and continuously in the time direction, and the excitation input intensity increases gradually according to the preset time interval. In the later stage of the energy gradual increase process, the timing of the excitation input is carefully controlled so that the excitation energy gradually transitions to the target excitation intensity in a continuous but nonlinear form. After the excitation energy gradually increases during the construction phase, a comprehensive correlation analysis is conducted on the time series, energy input magnitude, and pavement response amplitude of the entire energy gradually increasing process. The complete excitation energy evolution trajectory is extracted, and the initial vibration response benchmark of the bonding interface is established.

[0008] Preferably, in the later stage of the excitation energy gradual increase construction stage, the time rhythm of the excitation input is segmented and controlled so that the excitation energy forms a smooth and convergent energy change curve in the time direction, and the continuity of energy input and the stability of vibration response are maintained during the energy change process. Thus, the energy increase and response are synchronously transitioned throughout the entire excitation input process to ensure the integrity of the excitation energy evolution trajectory.

[0009] Preferably, the steps for expanding and comparing the road surface vibration response signal based on the excitation energy evolution trajectory are as follows: The road vibration response signal is synchronously unfolded according to the time series of the excitation energy evolution trajectory, so that the vibration response at each moment is in one-to-one correspondence with the corresponding excitation energy state. Based on the time-series consistent unfolded response data, the vibration response at different energy levels is compared segment by segment according to the energy change law of the excitation energy evolution trajectory. After completing the energy progression comparison, the response differences between each energy stage are separated and processed to extract the subtle vibration difference components generated by the change of excitation energy from the overall vibration response. After obtaining the subtle vibration differences, these differences are mapped in the frequency domain according to the corresponding time series to generate spectral difference clues that reflect the relative slip changes between pavement structure layers.

[0010] Preferably, when performing segment-by-segment comparison processing on the road vibration response signal, a mapping relationship between the excitation energy change and the structural response difference is established through the response differences of adjacent energy stages. When separating the subtle vibration difference components, the common response part under the condition of constant energy is eliminated. In the frequency domain mapping process, a time and frequency dual-dimensional difference distribution map is constructed with the excitation energy evolution trajectory as the time principal axis.

[0011] Preferably, the phase shift analysis steps introduced along the time axis along the spectral difference clues are as follows: Based on the obtained spectral difference clues, the spectral difference is continuously tracked along the time axis to ensure that the temporal distribution of the spectral difference is consistent with the trajectory of excitation energy evolution. Phase shift extraction is performed on the vibration response signal corresponding to the spectral differences based on the established time distribution sequence, so that the relative vibration phase relationship between structural layers can be clearly revealed. The continuity and directionality of phase shift are extended by analyzing the phase shift trajectory, so that the phase shift reflects the cumulative shift characteristics of the phase over time. After obtaining the temporal continuous distribution of phase shift, the directionality, persistence and amplitude changes of phase shift are comprehensively correlated to form a decohesion pointing mark used to characterize the decohesion trend between layers.

[0012] Preferably, the temporal distribution of spectral differences is synchronously matched with the time series of excitation energy evolution trajectory, so that the time nodes of phase shift are consistent with the energy change state. This achieves temporal coupling between spectral difference clues and excitation energy evolution trajectory in phase shift analysis, thereby improving the temporal continuity of interlayer relative motion and the accuracy of phase shift identification.

[0013] Preferably, the steps for adjusting the reverse beat of the excitation energy evolution trajectory based on the inviscid pointing marker are as follows: Based on the formed deindustry pointing markers, the corresponding time periods in the excitation energy evolution trajectory are identified, and the time interval where the deindustry pointing markers are located is determined as the starting region for the reverse adjustment of excitation energy. After determining the inverse adjustment starting region, the excitation energy evolution trajectory is controlled by a step-by-step reverse decrease, so that the energy density of the excitation input gradually decreases over time. As the excitation energy gradually decreases along the time direction, the vibration response of the pavement structure layer is dynamically focused, so that the vibration characteristics related to the interlayer relative displacement can be enhanced synchronously. After completing the reverse beat adjustment and vibration characteristic enhancement, the excitation energy change curve and structural layer response characteristics during the energy reduction process are correlated and integrated to construct a stability judgment baseline for determining the bond state.

[0014] Preferably, when implementing beat-reverse reduction control on the excitation energy evolution trajectory, by maintaining a continuous change in the energy reduction rate on the time axis, the excitation input forms a smooth energy decay curve, and the vibration response time series of the pavement structure layer is recorded synchronously during the energy reduction process, so that the excitation energy change and the interlayer relative displacement characteristics maintain a time correspondence, thereby ensuring the continuity and consistency of the stability determination baseline establishment process.

[0015] Preferably, the steps for triggering reverse breathing excitation adjustment based on the determination baseline are as follows: Based on the established stability determination baseline, the energy cycle boundary of the breathing excitation regulation is determined in the time dimension, so that the starting point of the energy cycle corresponds to the energy stability interval in the determination baseline. After determining the energy cycle boundary, the energy convergence triggering process is initiated, so that the excitation energy is gradually reduced from the baseline level along the time direction to form a breathing-like convergence phase; After completing the energy convergence phase, the energy unfolding feedback phase begins, which gradually restores the excitation energy from the convergence state and exceeds the baseline level to form a breathing-like unfolding phase. By correlating the response changes during the energy convergence and energy expansion phases during the continuous energy breathing cycle, the interlayer micro-motion differences remain discernible during periodic energy fluctuations.

[0016] The technical effects and advantages provided by the present invention in the above technical solution are as follows: This invention implements gradual energy increase control and establishes an excitation energy evolution trajectory during the excitation input stage, enabling a smooth transition of excitation intensity along the time direction. This avoids the overall high-amplitude response interference caused by sudden energy surges, allowing the subtle relative displacement of the interlaminar bonding interface to gradually manifest in the low to medium energy stage. By using time-consistent expansion and spectral difference comparison, the subtle response components caused by interlaminar slip are stably extracted during continuous energy changes, thereby obtaining spectral characteristics that accurately reflect changes in the interlaminar bonding state of the structure. This achieves the separation of vibration response from the overall dominant mode to local interlaminar features.

[0017] This invention introduces phase shift analysis along spectral difference clues and implements reverse beat adjustment and breathing-style excitation regulation based on debonding direction markers, enabling a dynamic temporal matching relationship between excitation energy and interlaminar response. This method maintains the discriminability of interlaminar micro-motion characteristics during testing, allowing the critical debonding state to be dynamically captured amidst energy cycle changes. By constructing a stable judgment baseline, continuous tracking and accurate identification of the interlaminar bonding state are achieved, effectively improving the sensitivity and stability of the test. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a flowchart of a field test method for the interlayer bonding state of pavement structures based on vibration spectrum analysis, according to the present invention. Detailed Implementation

[0020] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0021] This invention provides, for example Figure 1 The method shown is an on-site test method for the interlayer bonding state of pavement structures based on vibration spectrum analysis, which includes the following steps: In the initial stage of the field test of the interlayer bonding state of the pavement structure, the energy of the excitation input of the excitation device is gradually controlled to make the excitation intensity change continuously along the time direction and form the excitation energy evolution trajectory, which is used to establish the initial vibration response benchmark of the interlayer bonding interface of the pavement structure. To accurately establish the initial vibration response baseline of the interlayer bonding interface of the pavement structure during the initial testing phase, it is necessary to implement gradual energy ramp-up control on the excitation input of the excitation device, ensuring continuous variation of the excitation intensity along the time direction and forming a smooth and traceable excitation energy evolution trajectory throughout the entire energy evolution process. Through dynamic and coordinated control of the timing characteristics, amplitude adjustment, energy release rhythm, and vibration propagation response of the excitation input, a continuous transition from low-energy triggering to high-energy response is achieved, thereby obtaining basic vibration response data that truly reflects the interlayer bonding state of the pavement structure. The specific implementation steps are as follows: In the initial stage of the gradual energy increase construction phase, the excitation device is pre-driven according to the set energy increase law, so that the excitation input is gradually applied to the surface layer of the pavement structure in a low amplitude and low frequency form during the initial time period. The purpose of this stage is to enable the pavement surface layer and base layer to generate a controllable micro-amplitude response under low energy excitation conditions, so as to avoid the overall resonance of the structure caused by sudden energy input. By controlling the rise rate of the excitation input, the excitation energy is made to rise continuously on the time axis, forming a monotonic correlation between energy and time. During this process, the intensity change of the excitation input is recorded as the initial segment of the initial excitation energy trajectory, serving as a reference for subsequent energy increases. At the same time, the initial vibration response of the pavement structure is synchronously acquired to determine the inherent response characteristics of each structural layer under low excitation energy, thereby establishing a basic reference for the subsequent energy evolution stage.

[0022] As the energy gradually increases, the output of the excitation device is finely adjusted to ensure a smooth and continuous change in excitation energy over time. The excitation input intensity increases gradually at preset time intervals, with each energy increase starting from the energy state of the previous moment, achieving a smooth, gradual progression of energy input. At this point, the pavement structure gradually transitions from an initial low-energy response to a moderate-intensity response, and the coordinated vibration relationship between different layers begins to emerge. By continuously monitoring the vibration response signal, the temporal differences in energy transfer between different structural layers can be observed, thus establishing a mapping relationship between excitation energy and structural response. This mapping relationship constitutes the middle segment of the excitation energy evolution trajectory, describing the correspondence between the temporal distribution of the excitation input intensity and the response amplitude of the structural layers, providing continuous transitional data for subsequently constructing a complete energy evolution trajectory.

[0023] In the later stage of the energy gradual increase process, the timing of the excitation input is meticulously controlled, allowing the excitation energy to gradually approach the target excitation intensity in a continuous but nonlinear manner, forming a smooth and convergent energy change curve. During this stage, the increase in excitation energy gradually decreases, transitioning the energy input process from linear growth to a gradual increase, ensuring that the excitation energy does not undergo abrupt changes when approaching the target intensity. In this way, while the overall response of the pavement structure is enhanced, the interaction between structural layers remains stable, avoiding the dominance effect of the overall vibration master mode caused by instantaneous jumps in the excitation input. The energy change and structural response change in this stage together constitute the final segment of the excitation energy evolution trajectory, forming a complete time-energy-response continuous curve. During this process, the bonding interface between pavement structural layers gradually transitions from a slight vibration response to a fully stressed state, and the dynamic characteristics of the bonding interface are fully excited and recorded, providing a basic response benchmark for subsequent bonding state determination.

[0024] After the gradual increase in excitation energy is completed, a comprehensive correlation analysis is performed on the time series, energy input magnitude, and pavement response amplitude of the entire energy increase process to extract the complete excitation energy evolution trajectory. This trajectory is then used as a reference to establish the initial vibration response benchmark for the interlayer bonding interface of the pavement structure. In this process, by mapping the time series of the excitation input to the structural response amplitude at each moment, an evolution curve of the excitation energy over time can be formed. The structural response at each moment on the curve serves as the dynamic characteristic identifier of the bonding interface. By establishing this benchmark, subsequent vibration response comparisons and spectral difference analyses can use this excitation energy evolution trajectory as a unified reference, enabling traceable analysis of changes in the bonding state. Simultaneously, this excitation energy evolution trajectory reflects the hierarchical relationship of the pavement structure layers under different energy inputs, allowing the mechanical properties of the interlayer bonding interface of the pavement structure to be characterized simultaneously in both time and energy dimensions. Thus, a complete energy control system was formed throughout the entire excitation input process, from low-energy probing, smooth energy increase, gradual energy convergence to the establishment of the energy evolution trajectory. This fully reflects the continuous change of excitation energy along the time direction, and on this basis, the initial vibration response benchmark of the bonding interface is obtained, providing a stable and repeatable input condition and reference framework for subsequent steps such as spectrum difference extraction, phase shift manifestation, and determination baseline construction.

[0025] Based on the excitation energy evolution trajectory, the collected road vibration response signals are expanded and compared in the same time sequence. The subtle vibration difference components generated by the change of excitation energy are separated in the overall vibration response, and spectral difference clues reflecting the relative slip change between the road structure layers are generated. After completing the step of gradually increasing the excitation energy and forming the excitation energy evolution trajectory, the acquired road vibration response signals need to be expanded and compared in the same time sequence based on this trajectory. This is to separate the subtle vibration differences caused by changes in excitation energy in the overall vibration response, and on this basis, generate spectral difference clues that can reflect the relative slip changes between the road structure layers. Through four stages—consistent time series expansion, energy mapping comparison, difference component separation, and spectral correlation extraction—the frequency domain response basis for the changes in the interlayer bonding state is constructed, so that the interlayer bonding characteristics are continuously reflected in both time and frequency dimensions. The specific steps are as follows: The road surface vibration response signal is synchronously unfolded according to the time series of the excitation energy evolution trajectory, ensuring a one-to-one correspondence between the vibration response at each moment and the corresponding excitation energy state. This time-consistent unfolding method ensures that subsequent comparison processes are based on the same energy input background, eliminating interference from non-energy factors in the comparison results. The unfolded vibration response signal forms a time-axis response sequence that matches the excitation energy evolution trajectory, with each segment of the response signal corresponding to a continuous growth stage of the excitation energy. Through this time series correspondence, the response changes between structural layers under different excitation energy levels can be tracked in subsequent comparisons, ensuring that each response stage reflects the stress evolution state of the structural layer bonding interface. This step not only ensures the accuracy of time alignment but also maintains the causal correspondence between the excitation input and the structural response during signal unfolding, providing a temporally continuous response basis for subsequent difference analysis.

[0026] Based on time-series consistent response data, the vibration responses at different energy levels are compared segment by segment according to the energy change patterns of the excitation energy evolution trajectory. During the comparison, the core focus is on the response differences between adjacent energy stages, using the continuous change of excitation energy as the comparison benchmark. The response of each energy stage is compared with the response of the previous stage to reveal the changing trends in interlayer vibration synergy, response amplitude ratio, and frequency distribution as energy increases. Through this progressive energy comparison, the response transformation path of the structural layers from low to high energy can be observed, especially identifying the critical energy range where interlayer relative motion begins. This process constructs a mapping relationship between excitation energy changes and structural response differences, allowing the subtle changes in the vibration response caused by energy variations to be displayed layer by layer, providing a clear energy reference framework for separating the differential components.

[0027] After completing the energy progression comparison, the response differences between each energy stage were separated to extract the subtle vibrational differences caused by changes in excitation energy from the overall vibration response. This separation process uses the vibrational response difference between adjacent energy stages as the analysis object, eliminating the common response portion under constant energy conditions through continuous comparison, thus retaining the differential vibrational components caused solely by energy changes. At this point, the previously masked weak interlayer relative slip response in the overall high-amplitude response background is separated out. By continuously comparing the response changes at different energy stages, subtle differences in interlayer relative displacement, interfacial friction characteristics, and local energy absorption states can be discovered, forming a differential response sequence that changes with excitation energy. The energy distribution and temporal characteristics of these differential responses together constitute a dynamic characterization of the changes in the interlayer bonding state, allowing the local slip effect, originally masked by the overall vibration master mode, to be revealed again in the time dimension.

[0028] After obtaining the subtle vibration differences, these differences are mapped in the frequency domain according to their corresponding time series, generating spectral difference clues reflecting the relative slip changes between pavement structure layers. In this process, the excitation energy evolution trajectory is used as the time axis, and the separated subtle differences are used as the frequency domain analysis objects. The energy state at each moment is combined with the frequency distribution of its corresponding difference components to construct a time-frequency dual-dimensional difference distribution map. This distribution map shows the evolution trend of response differences between structural layers in different frequency ranges as the excitation energy changes continuously. Through this mapping relationship, the slip change path generated at the bonding interface between structural layers during the gradual increase of energy can be tracked, thus forming spectral difference clues with time extension and energy correlation. These spectral difference clues can reflect subtle changes in the cooperative vibration relationship between structural layers, providing a clear analytical basis for subsequent phase shift manifestation steps.

[0029] Phase shift analysis is introduced along the time axis along the spectral difference clues, so that the relative motion between pavement structure layers is gradually revealed in the form of continuous phase shift, and a debonding indicator is formed during the phase shift process to characterize the debonding trend between layers. After completing the vibration response unfolding and comparison based on the excitation energy evolution trajectory and obtaining spectral difference clues that can reflect the relative slip changes between pavement structure layers, phase shift analysis needs to be introduced along the time axis along the spectral difference clues. This allows the relative motion between pavement structure layers to be gradually revealed in the form of continuous phase shifts, and during the phase shift process, debonding directional markers are formed to characterize the debonding trend between layers. This process, through continuous time tracking, phase shift extraction, phase correlation extension, and debonding marker solidification unfolding, transforms the implicit characteristics of interlayer relative motion from frequency domain differences into observable characteristics in the time dimension, thereby revealing the gradual process of the bonded interface changing from cooperative vibration to separation motion. The specific steps are as follows: Based on the obtained spectral difference clues, the spectral differences are continuously tracked along the time axis, ensuring that the temporal distribution of the spectral differences is consistent with the evolution trajectory of the excitation energy. This ensures that the spectral difference at each moment corresponds to a specific energy state during the excitation energy change process. This time-consistent tracking method establishes a bidirectional correspondence between the temporal variation of the spectral differences and the energy variation, thereby establishing a continuous distribution sequence of spectral differences along the time axis. This distribution sequence reflects the evolution path of response differences between pavement structure layers at different energy input stages, providing continuous temporal support for subsequent phase shift analysis. In this process, the temporal distribution of the spectral difference clues not only records the changes in the amplitude of the interlayer response but also implicitly contains information on the synchronicity of the responses of each structural layer, enabling the dynamic coupling state of the bonding interface at different energy levels to be expressed temporally.

[0030] Based on the established time distribution sequence, phase shifts are extracted from the vibration response signals corresponding to spectral differences, clearly revealing the relative vibration phase relationships of different structural layers at the same excitation energy stage. By continuously extracting the phase relationship within each time interval, the gradual trend of the relative motion between structural layers over time can be observed. When the structural layers are well bonded, the phase relationship remains stable and the phase difference is constant; as the energy increases, if there is slippage or micro-voidage at the interlayer bonding interface, the phase difference begins to shift gradually. This phase shift unfolds along the time axis in a continuously changing form, forming a phase shift trajectory. By introducing this phase shift trajectory into the spectral difference clues, the vibration differences that could only be observed in the frequency domain are transformed into a phase shift process that can be continuously tracked in the time domain, thus providing a dynamic reference basis for identifying interlayer debonding trends.

[0031] Extending the analysis of the continuity and directionality of phase shift along the phase shift trajectory allows the phase shift to reflect not only instantaneous phase differences but also the cumulative phase shift characteristics over time. In this stage, using temporal continuity as the main thread, the phase shifts of adjacent time periods are extended and compared, enabling a synchronous description of the growth direction, growth rate, and relationship with changes in excitation energy. This method allows identification of the process by which the interlayer bond interface gradually transitions from synchronous vibration to asynchronous vibration under continuous energy input. When a stable cumulative trend of phase shift emerges, it signifies that the coordinated vibration relationship between the structural layers has been disrupted, and local slippage begins at the interface. The continuous phase shift distribution formed in this stage not only reveals the transition path of the bond interface from stable to unstable but also reflects the temporal evolution of the debonding process, providing a physical basis for determining the characteristic intervals of the debonding trend.

[0032] After obtaining the temporal continuous distribution of phase shift, the directionality, persistence, and amplitude changes of phase shift are comprehensively correlated to form a debonding indicator for characterizing the interlayer debonding trend. In this process, the phase shift trajectory is combined with spectral difference clues, ensuring that the time nodes of phase shift correspond to changes in spectral energy distribution, thus simultaneously reflecting the debonding trend in both time and frequency dimensions. When the phase shift direction remains consistent and the shift amplitude exceeds the stable range, the corresponding time period is recorded on the time axis as the generation point of the debonding indicator. This debonding indicator reflects the key node where interlayer relative motion shifts from cooperation to separation, and forms a traceable debonding trend path in the excitation energy evolution trajectory. Through this indicator, spectral differences, phase shift, and temporal changes can be unified under the same coordinate system, allowing the interlayer debonding process to gradually manifest in the form of continuous shifts, constructing a time-series indicator system for bonding interface failure.

[0033] Based on the debonding pointing mark, the excitation energy evolution trajectory is adjusted in reverse beat, so that the overall high-energy vibration response gradually weakens along the time sequence, and the vibration characteristics related to the relative displacement between pavement structure layers are enhanced simultaneously, and a stable judgment baseline for bond state determination is constructed. After obtaining the debonding indicator to characterize the interlayer debonding trend, the excitation energy evolution trajectory needs to be adjusted in reverse beat according to this indicator. This causes the overall high-energy vibration response to gradually decrease over time, while simultaneously enhancing vibration characteristics related to the relative displacement between pavement structure layers, thereby constructing a stable baseline for determining the bonding state. This process, through debonding region identification, reverse beat reduction, response enhancement focusing, and baseline stabilization construction, dynamically matches the temporal structure of the excitation input energy with the relative interlayer characteristics of the structural layer response, achieving active control over the vibration behavior of the bonding interface. The specific steps are as follows: Based on the formed debonding pointing markers, the corresponding time periods in the excitation energy evolution trajectory are identified, and the time intervals where the debonding pointing markers are located are determined as the starting region for the reverse adjustment of excitation energy. In this stage, the phase shift trajectory and spectral difference clues reflected by the debonding pointing markers are used to determine the time segments most sensitive to the relative motion between structural layers. In this way, the time axis of the excitation energy evolution trajectory is synchronized with the characteristics of changes in the bonding state of the structural layers, providing a clear time-domain starting point for subsequent reverse timing adjustments. During the identification process, the debonding pointing markers not only serve as reference points for the trigger signal but also as control benchmarks for energy adjustment, ensuring a time correspondence between the adjustment action of the excitation energy and the response behavior between structural layers. This guarantees that the reverse adjustment process unfolds guided by changes in interlayer bonding.

[0034] After determining the initiation region of the reverse adjustment, a beat-reverse decreasing control is implemented on the excitation energy evolution trajectory, causing the energy input process, which originally increased over time, to gradually weaken sequentially. At this point, by extending the rhythm of the excitation energy in reverse along the time axis, the energy density of the excitation input slowly decreases over time. As the excitation energy gradually decreases, the overall high-energy vibration response gradually transitions from a strong overall vibration state to a medium-to-low energy response state, thereby suppressing the dominant effect of the overall structural vibration mode. This reverse-beat energy adjustment method can reduce the overall response amplitude while maintaining the relative differences in local responses, thus creating favorable conditions for the enhancement of interlayer relative displacement characteristics. The reverse-beat adjustment process in this stage maintains a continuous temporal correspondence with the debonding indicator, ensuring that the energy decreasing process accurately covers the critical period of interlayer debonding occurrence and development, and ensuring that changes in interlayer bonding state are fully manifested under controlled energy conditions.

[0035] As the excitation energy gradually decreases over time, the vibration response of the pavement structure layers is dynamically focused. This allows for the synchronous enhancement of local vibration characteristics related to interlayer relative displacement during the overall response decay caused by energy reduction. By continuing the reverse beat adjustment time rhythm, the energy input forms a controllable decay sequence within each time period, thereby enhancing the expression of subtle vibration behaviors such as relative slippage, micro-voiding, and local friction at the bonding interface against the backdrop of weakened overall response. During this stage, the relative motion between pavement structure layers gradually shifts from being masked by the overall response to becoming a dominant component of the response. The characteristic frequency bands corresponding to interlayer interactions in the spectral difference clues begin to expand again, and the temporal continuity of relative motion in the phase shift trajectory is prolonged. This response focusing under reverse energy reduction conditions makes the dynamic characteristics of the interlayer bonding interface clearer under low excitation energy conditions, providing a dynamic response data foundation for constructing a stable baseline for bonding state determination.

[0036] After completing the reverse beat adjustment and vibration characteristic enhancement, the excitation energy change curve and structural layer response characteristics throughout the energy reduction process are correlated and integrated to construct a stable determination baseline for bond state assessment. In this stage, the time series of the excitation energy evolution trajectory is combined with the time distribution of interlayer relative displacement characteristics, ensuring a consistent correspondence between the two on the time axis. This correspondence forms a stable mapping between energy level and response amplitude, thus establishing a vibration response baseline unaffected by sudden energy changes. This baseline reflects the stable response range and trend of interlayer structures under different energy input levels, serving as a crucial reference for distinguishing between well-bonded and unbonded states. During the baseline formation process, the smooth energy transition introduced by the reverse beat adjustment ensures the continuity and repeatability of the response curve, giving the baseline not only smoothness in the energy time dimension but also stability in the structural response dimension. Therefore, the bond state between pavement structural layers can be reliably determined without being affected by instantaneous energy changes, ensuring the accuracy and stability of subsequent bond state identification.

[0037] Based on the judgment baseline triggering reverse breathing excitation adjustment, through the periodic convergence and expansion of excitation energy, the micro-motion differences between pavement structure layers are kept discernible during the test, realizing the dynamic control and identification of the critical de-adhesion state. After completing the reverse beat adjustment of the excitation energy based on the debonding directional marker and establishing a stable judgment baseline, it is necessary to trigger reverse breathing-type excitation adjustment based on this judgment baseline. Through the periodic convergence and expansion of the excitation energy, the micro-motion differences between the pavement structure layers remain discernible during the test, thereby achieving dynamic control and identification of the critical debonding state. This process is completed through energy breathing cycle setting, energy convergence triggering, energy expansion feedback, and dynamic identification and maintenance, so that the excitation input energy forms a rhythmic change of regular contraction and release over time, ensuring that the micro-motion response of the bonding interface between structural layers is always within the observable range, and exhibiting the dynamic evolution characteristics of the bonding state in the periodic changes of energy. The specific steps are as follows: Based on the established stability baseline, the energy cycle boundary of the breathing-type excitation regulation is determined in the time dimension, aligning the starting point of the energy cycle with the stable energy range in the baseline, thus forming a cyclical framework of energy convergence and expansion centered on a stable energy level. In this stage, by analyzing the correspondence between energy and response amplitude in the baseline, the upper and lower limits of energy that maintain the distinguishability of inter-layer relative motion are extracted, and this range is used as the energy envelope for reverse breathing-type excitation regulation. This energy envelope exhibits regular fluctuations on the time axis, allowing the excitation energy to be periodically adjusted around the baseline. In this way, the excitation input no longer maintains a monotonically increasing or continuously decreasing state, but instead forms a rhythmic convergence and expansion change over time, providing a stable energy framework for subsequent dynamic regulation.

[0038] After determining the energy cycle boundary, an energy convergence triggering process is initiated, causing the excitation energy to gradually decrease along the time direction from the baseline level, forming a breathing-like "convergence" phase. During this phase, the rate of decrease in the excitation input energy remains continuously varied, causing the amplitude of the overall vibration response of the pavement structure layers to gradually decrease. As the energy converges, the overall response tends to stabilize, while the differences in interlayer micromotions gradually become more prominent. At this point, the subtle slippage, localized delamination, and weak bonding characteristics between the structural layers, which were previously masked by high-energy excitation, become discernible again under the reduced overall vibration environment. By maintaining coordination between the duration and energy amplitude of the energy convergence phase, the interlayer micromotions maintain response continuity during energy reduction, thereby exposing the dynamic characteristics of the critical delamination range without compromising the overall structural stability. The role of this phase is to suppress the coverage of local responses by the overall modal vibration through orderly convergence of excitation energy, allowing the details of the relative motion between layers to be presented independently.

[0039] After the energy convergence phase, the energy unfolding feedback phase begins, allowing the excitation energy to gradually recover from the convergence state and exceed the baseline level, thus forming a breathing-like "unfolding" phase. In this phase, the excitation energy gradually increases smoothly over time, causing the pavement structure to re-enter a high-response state. Since the energy convergence phase in the previous stage has fully revealed the interlayer micromotion characteristics, the energy unfolding process at this stage allows observation of the response changes of these micromotion characteristics under enhanced energy conditions. As the excitation energy gradually unfolds, the relative slip and phase difference between structural layers begin to periodically amplify or weaken, further amplifying the response differences under different bonding states. By forming a time-continuous closed loop between the energy unfolding and energy convergence phases, the structural layers undergo a transition from a low-energy stable state to a high-energy excitation state within a complete breathing cycle, allowing for dynamic recording of the response evolution of the bonding interface under different energy input levels. This energy unfolding phase not only restores the integrity of the overall vibration response but also provides new starting conditions for energy convergence in the next cycle, creating a cyclical system of energy regulation and response evolution throughout the entire testing process.

[0040] During the continuous energy breathing cycle, the response changes in each energy convergence and energy expansion stage are temporally correlated, ensuring that the interlayer micro-motion differences remain distinguishable amidst periodic energy fluctuations. This dynamic maintenance enables the regulation and identification of the critical debonding state. In this stage, the energy fluctuation curves formed within multiple breathing cycles are synchronized with the structural layer response change curves, allowing the relative motion between structural layers to exhibit a regular response pattern under periodically alternating energy inputs. Through this periodic regulation, the structural layer interface in the critical bonding state is not masked by overall vibration during energy changes, nor does it lose its response due to insufficient energy, thus achieving continuous monitoring and identification of the critical debonding state. The energy convergence stage reveals the stable characteristics of the bonding interface, while the energy expansion stage amplifies its unstable characteristics. Their alternating action ensures that the dynamic evolution of the bonding state is fully presented throughout the entire test cycle. Through continuous breathing-style excitation adjustment, the test process maintains the dynamic distinguishability of the interlayer response without damaging the pavement structure, thereby achieving long-term traceable monitoring and accurate identification of the bonding state.

[0041] This invention implements gradual energy increase control and establishes an excitation energy evolution trajectory during the excitation input stage, enabling a smooth transition of excitation intensity along the time direction. This avoids the overall high-amplitude response interference caused by sudden energy surges, allowing the subtle relative displacement of the interlaminar bonding interface to gradually manifest in the low to medium energy stage. By using time-consistent expansion and spectral difference comparison, the subtle response components caused by interlaminar slip are stably extracted during continuous energy changes, thereby obtaining spectral characteristics that accurately reflect changes in the interlaminar bonding state of the structure. This achieves the separation of vibration response from the overall dominant mode to local interlaminar features.

[0042] This invention introduces phase shift analysis along spectral difference clues and implements reverse beat adjustment and breathing-style excitation regulation based on debonding direction markers, enabling a dynamic temporal matching relationship between excitation energy and interlaminar response. This method maintains the discriminability of interlaminar micro-motion characteristics during testing, allowing the critical debonding state to be dynamically captured amidst energy cycle changes. By constructing a stable judgment baseline, continuous tracking and accurate identification of the interlaminar bonding state are achieved, effectively improving the sensitivity and stability of the test.

[0043] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A field testing method for the interlayer bonding state of pavement structures based on vibration spectrum analysis, characterized in that, Includes the following steps: In the initial stage of the field test of the bonding state between pavement structure layers, the energy of the excitation input of the excitation device is gradually controlled to make the excitation intensity change continuously along the time direction and form an excitation energy evolution trajectory. Based on the excitation energy evolution trajectory, the collected road vibration response signals are expanded and compared in the same time sequence to separate the subtle vibration difference components generated by the change of excitation energy in the overall vibration response and generate spectral difference clues. Phase shift analysis is introduced along the time axis along the spectral difference clues, so that the relative motion between pavement structure layers is gradually revealed in the form of continuous phase shift, and a deadhesion pointing mark is formed during the phase shift process. Based on the deintegration pointing mark, the excitation energy evolution trajectory is adjusted in reverse beat, so that the overall high-energy vibration response gradually weakens along the time sequence, and the vibration characteristics related to the relative displacement between pavement structure layers are enhanced simultaneously, thus constructing a stability judgment baseline; Based on the baseline-triggered reverse breathing vibration regulation, the periodic convergence and expansion of the excitation energy ensures that the micro-motion differences between pavement structure layers remain discernible during the test.

2. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 1, characterized in that, The formation process of the excitation energy evolution trajectory is as follows: In the initial stage of the gradual energy increase construction phase, the excitation device is pre-driven according to the set energy increase law, so that the excitation input is gradually applied to the surface of the road structure in the form of low amplitude and low frequency during the initial time period. When the energy gradually increases to the middle stage, the output of the excitation device is finely adjusted so that the excitation energy changes smoothly and continuously in the time direction, and the excitation input intensity increases gradually according to the preset time interval. In the later stage of the energy gradual increase process, the timing of the excitation input is carefully controlled so that the excitation energy gradually transitions to the target excitation intensity in a continuous but nonlinear form. After the excitation energy gradually increases during the construction phase, a comprehensive correlation analysis is conducted on the time series, energy input magnitude, and road surface response amplitude of the entire energy gradually increasing process. The complete excitation energy evolution trajectory is extracted, and the initial vibration response benchmark of the bonding interface is established.

3. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 2, characterized in that, In the later stage of the gradual increase of excitation energy, the time rhythm of the excitation input is controlled in segments to make the excitation energy form a smooth and convergent energy change curve in the time direction, and to maintain the continuity of energy input and the stability of vibration response during the energy change process.

4. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 2, characterized in that, The steps for expanding and comparing the road surface vibration response signal based on the excitation energy evolution trajectory are as follows: The road vibration response signal is synchronously unfolded according to the time series of the excitation energy evolution trajectory, so that the vibration response at each moment is in one-to-one correspondence with the corresponding excitation energy state. Based on the time-series consistent unfolded response data, the vibration response at different energy levels is compared segment by segment according to the energy change law of the excitation energy evolution trajectory. After completing the energy progression comparison, the response differences between each energy stage are separated and processed to extract the subtle vibration difference components generated by the change of excitation energy from the overall vibration response. After obtaining the subtle vibration differences, these differences are mapped in the frequency domain according to the corresponding time series to generate spectral difference clues that reflect the relative slip changes between pavement structure layers.

5. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 4, characterized in that, When performing segment-by-segment comparison processing on the road vibration response signal, a mapping relationship between the excitation energy change and the structural response difference is established by the response difference between adjacent energy stages. When separating the subtle vibration difference components, the common response part under the condition of constant energy is eliminated. In the frequency domain mapping process, a time and frequency dual-dimensional difference distribution map is constructed with the excitation energy evolution trajectory as the time principal axis.

6. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 4, characterized in that, The steps for introducing phase shift analysis along the time axis using spectral difference clues are as follows: Based on the obtained spectral difference clues, the spectral difference is continuously tracked along the time axis to ensure that the temporal distribution of the spectral difference is consistent with the trajectory of excitation energy evolution. Phase shift extraction is performed on the vibration response signal corresponding to the spectral differences based on the established time distribution sequence, so that the relative vibration phase relationship between structural layers can be clearly revealed. The continuity and directionality of phase shift are extended by analyzing the phase shift trajectory, so that the phase shift reflects the cumulative shift characteristics of the phase over time. After obtaining the temporal continuous distribution of phase shift, the directionality, duration, and amplitude changes of phase shift are comprehensively correlated to form a deinelution pointing mark.

7. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 6, characterized in that, By synchronously matching the temporal distribution of spectral differences with the time series of excitation energy evolution trajectory, the time nodes of phase shift are kept consistent with the energy change state, thereby realizing the temporal coupling of spectral difference clues and excitation energy evolution trajectory in phase shift analysis.

8. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 6, characterized in that, The steps for adjusting the reverse beat of the excitation energy evolution trajectory based on the inviscid pointing marker are as follows: Based on the formed deindustry pointing markers, the corresponding time periods in the excitation energy evolution trajectory are identified, and the time interval where the deindustry pointing markers are located is determined as the starting region for the reverse adjustment of excitation energy. After determining the inverse adjustment starting region, the excitation energy evolution trajectory is controlled by a step-by-step reverse decrease, so that the energy density of the excitation input gradually decreases over time. As the excitation energy gradually decreases along the time direction, the vibration response of the pavement structure layer is dynamically focused, so that the vibration characteristics related to the interlayer relative displacement can be enhanced synchronously. After completing the reverse beat adjustment and vibration characteristic enhancement, the excitation energy change curve and structural layer response characteristics during the energy reduction process are correlated and integrated to construct a stability determination baseline.

9. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 8, characterized in that, When implementing beat-reverse reduction control on the excitation energy evolution trajectory, by maintaining a continuous change in the energy reduction rate on the time axis, the excitation input forms a smooth energy decay curve, and the vibration response time series of the pavement structure layer is recorded synchronously during the energy reduction process, so that the excitation energy change and the interlayer relative displacement characteristics maintain a time correspondence.

10. The field testing method for interlayer bonding state of pavement structure based on vibration spectrum analysis according to claim 8, characterized in that, The steps for triggering reverse breathing-type excitation adjustment based on the baseline determination are as follows: Based on the established stability determination baseline, the energy cycle boundary of the breathing excitation regulation is determined in the time dimension, so that the starting point of the energy cycle corresponds to the energy stability interval in the determination baseline. After determining the energy cycle boundary, the energy convergence triggering process is initiated, so that the excitation energy is gradually reduced from the baseline level along the time direction to form a breathing-like convergence phase; After completing the energy convergence phase, the energy unfolding feedback phase begins, which gradually restores the excitation energy from the convergence state and exceeds the baseline level to form a breathing-like unfolding phase. By correlating the response changes during the energy convergence and energy expansion phases during the continuous energy breathing cycle, the interlayer micro-motion differences remain discernible during periodic energy fluctuations.

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