CN114414184A - Infrastructure foundation safety monitoring and evaluating method - Google Patents

Abstract

The invention discloses an infrastructure safety monitoring and evaluating method, which comprises the following steps: A. the test system comprises: starting from a sensor, the system can be an accelerometer and a velocimeter, and also can start from a position determined by a satellite GPS and a Beidou, and analyze an amplitude time frequency spectrum and a corresponding edge spectrum of acceleration through Hilbert-Huang transform. The invention analyzes the frequency spectrum of the acceleration amplitude time and the corresponding edge spectrum through a sensor and an accelerometer and through Hilbert-Huang transformation, then compares the edge spectrum with some existing spectrums of healthy structures to determine whether frequency peak screening and broadening exist or not so as to determine whether damage and the severity of the damage exist or not, and solves the problems that the foundation is usually submerged, the inspection is difficult, the range of the scouring depth is greatly changed, even if the visual inspection is carried out, the safety of the structure cannot be determined by only observing the scouring depth, and the safety determination is not easy.

Description

Basic safety monitoring and evaluation method of infrastructure

technical field

The invention relates to the technical field of infrastructure, in particular to a method for monitoring and evaluating the basic safety of infrastructure.

Background technique

The safety of infrastructure is equal to the safety of society. The key to infrastructure construction is infrastructure such as bridge abutments, offshore wind turbine towers, and dam bodies. For bridges and offshore wind turbine towers, the foundation is usually submerged, which makes inspection difficult. However, According to ASCE's research, scour is the leading cause of bridge failure, and according to the data collected, localized scour accounts for 64% of bridge failures, followed by channel migration (14%) and shrinkage scour (5%), with most scour depths (up to 41%). %) is between 0.5 and 5m; the maximum scour depth can reach 15m, and the range of scour depth varies greatly, even with a visual inspection, only observing the scour depth is not enough to determine the safety of the structure, which is not an easy task.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an infrastructure foundation safety monitoring and evaluation method, which has the advantages of convenient judgment, and solves the problem that the foundation is usually submerged, which makes inspection difficult, and the range of the scouring depth varies greatly. Even if a visual inspection is performed, only the scour is observed. Nor is the depth deep enough to determine the safety of a structure, which is not an easy problem.

In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for monitoring and evaluating the basic safety of infrastructure, and the steps of the monitoring and evaluating method are as follows:

A. Test system: Starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage;

B. Determine the relative stiffness of any given structure to its full counterpart by inferring stiffness changes from frequency ratios;

C. The frequency can also be derived from the location determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis;

D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency;

D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state;

D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage;

D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage;

therefore

E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

therefore

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16);

E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading, and frequency downshift is a clear indication of damage. and shall be marked;

F. Acceleration records were obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, which indicates the need for caution, safety, caution or danger criteria in which damage is also identified The severity is determined according to the table given:

S=f/fo=To/T

Frequency of the first mode

the period of the first mode;

0.85s 1 safe

0.70s < 0.85 warning

S<0.70 requires detailed inspection;

now (broken) vs used (not broken)

0.90s 1 safe

0.80s < 0.90 warning

S<0.80 requires detailed examination.

Preferably, the stiffness change in step B is measured in frequency by an accelerometer connected to the structure to be inspected, and the data should be analyzed by Hilbert-Huang analysis.

Preferably, the vibration of the bridge pier and the tower in the step D can be regarded as a cantilever beam anchored on the foundation or as an extension of the foundation pile.

Preferably, in the step D1, the square of the frequency is proportional to the stiffness, and the change of the vibration frequency is used to judge the integrity of the structure, and the change of the frequency can be used as a measure of damage.

Preferably, in the step E1, heavy load may cause nonlinear vibration, and light load may cause linear vibration.

Preferably, the step frequency peak broadening in D4 is close to the nonlinear range.

Preferably, in the step F, the acceleration records are obtained in mixed light-load and heavy-load traffic, and the corresponding edge spectrum is calculated according to the Hilbert-Huang transform.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. The present invention analyzes the amplitude time spectrum and the corresponding edge spectrum of acceleration through sensors and accelerometers, and through the Hilbert-Huang transform, and then compares the edge spectrum with some existing spectrum of healthy structures to determine whether there is a frequency Peak screening, broadening to determine the presence of damage and its severity, with satellite GPS, BeiDou and velocimeters, the location can be determined, and it is concluded that vibration can be caused by artificial loads or environmental forcing, and its presence is determined by testing at each site and location, the severity can be determined by the relative stiffness changes with respect to the intact state or the intact state, by mixing light and heavy loads, obtaining acceleration records in traffic, calculating the corresponding fringe spectrum according to the Hilbert-Huang transform, For relatively heavy loads of cc020 loads, it is easy to see peak broadening, which indicates the need for caution, a safety, caution, or danger criterion, which also determines the severity of the damage.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The basic safety monitoring and evaluation method of infrastructure, the monitoring and evaluation method steps are as follows:

A. Test system: Starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage;

B. Determine the relative stiffness of any given structure to its full counterpart by inferring stiffness changes from frequency ratios;

C. The frequency can also be derived from the location determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis;

D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency;

D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state;

D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage;

D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage;

therefore

E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

therefore

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16);

E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading, and frequency downshift is a clear indication of damage. and shall be marked;

F. Acceleration records were obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, which indicates the need for caution, safety, caution or danger criteria in which damage is also identified The severity is determined according to the table given:

S=f/fo=To/T

Frequency of the first mode

the period of the first mode;

0.85s 1 safe

0.70s < 0.85 warning

S<0.70 requires detailed inspection;

now (broken) vs used (not broken)

0.90s 1 safe

0.80s < 0.90 warning

S<0.80 requires detailed examination.

Embodiment 2:

In Embodiment 1, the following steps are added:

The stiffness change in step B is measured in frequency by an accelerometer attached to the structure to be inspected, and the data should be analyzed by Hilbert-Huang analysis.

Its monitoring and evaluation method steps are as follows:

A. Test system: Starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage;

B. Determine the relative stiffness of any given structure to its full counterpart by inferring stiffness changes from frequency ratios;

C. The frequency can also be derived from the location determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis;

D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency;

D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state;

D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage;

D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage;

therefore

E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

therefore

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16);

E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading, and frequency downshift is a clear indication of damage. and shall be marked;

F. Acceleration records were obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, which indicates the need for caution, safety, caution or danger criteria in which damage is also identified The severity is determined according to the table given:

S=f/fo=To/T

Frequency of the first mode

the period of the first mode;

0.85s 1 safe

0.70s < 0.85 warning

S<0.70 requires detailed inspection;

now (broken) vs used (not broken)

0.90s 1 safe

0.80s < 0.90 warning

S<0.80 requires detailed examination.

Embodiment three:

In embodiment two, add the following procedure:

The vibrations of the piers and towers in Step D can be viewed as cantilever beams anchored to the foundation or as extensions of the foundation piles.

Its monitoring and evaluation method steps are as follows:

A. Test system: Starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage;

B. Determine the relative stiffness of any given structure to its full counterpart by inferring stiffness changes from frequency ratios;

C. The frequency can also be derived from the location determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis;

D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency;

D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state;

D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage;

D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage;

therefore

E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

therefore

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16);

E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading, and frequency downshift is a clear indication of damage. and shall be marked;

F. Acceleration records are obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, indicating the need for caution, safety, caution or danger criteria, in which damage is also identified The severity is determined according to the table given:

S=f/fo=To/T

Frequency of the first mode

the period of the first mode;

0.85s 1 safe

0.70s < 0.85 warning

S<0.70 requires detailed inspection;

now (broken) vs used (not broken)

0.90s 1 safe

0.80s < 0.90 warning

S<0.80 requires detailed examination.

Embodiment 4:

In embodiment three, add the following procedure:

In step D1, the square of the frequency is proportional to the stiffness, and the change of the vibration frequency is used to judge the integrity of the structure, and the change of the frequency can be used as a measure of damage.

Its monitoring and evaluation method steps are as follows:

A. Test system: Starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage;

B. Determine the relative stiffness of any given structure to its full counterpart by inferring stiffness changes from frequency ratios;

C. The frequency can also be derived from the location determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis;

D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency;

D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state;

D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage;

D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage;

therefore

E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

therefore

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16);

E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading, and frequency downshift is a clear indication of damage. and shall be marked;

F. Acceleration records were obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, which indicates the need for caution, safety, caution or danger criteria in which damage is also identified The severity is determined according to the table given:

S=f/fo=To/T

Frequency of the first mode

the period of the first mode;

0.85s 1 safe

0.70s < 0.85 warning

S<0.70 requires detailed inspection;

now (broken) vs used (not broken)

0.90s 1 safe

0.80s < 0.90 warning

S<0.80 requires detailed examination.

Embodiment 5:

In embodiment four, add the following procedure:

Heavy loads in step E1 may cause nonlinear vibrations, and light loads may cause linear vibrations.

Its monitoring and evaluation method steps are as follows:

A. Test system: starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage;

B. Determine the relative stiffness of any given structure to its intact counterpart by inferring stiffness changes from frequency ratios;

C. The frequency can also be derived from the position determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis;

D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency;

D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state;

D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage;

D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage;

therefore

E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

therefore

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16);

E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading. Frequency downshift is a clear indication of damage. and shall be marked;

F. Acceleration records are obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, which indicates the need for caution, safety, caution or danger criteria in which damage is also identified The severity is determined according to the table given:

S=f/fo=To/T

Frequency of the first mode

the period of the first mode;

0.85s 1 safe

0.70s < 0.85 warning

S<0.70 requires detailed inspection;

now (broken) vs used (not broken)

0.90s 1 safe

0.80s < 0.90 warning

S<0.80 requires detailed examination.

The standard parts used in this application document can be purchased from the market, and can be customized according to the description in the manual. The machinery, parts and equipment all use conventional models in the prior art, the control method is automatically controlled by the controller, and the control circuit of the controller can be realized by simple programming by those skilled in the art, which belongs to the common knowledge in the art, and This application is mainly used to protect mechanical devices, so this application will not explain the control method and circuit connection in detail.

It should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principle and spirit of the invention and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (7)

1. The basic safety monitoring and evaluation method of infrastructure is characterized in that: its monitoring and evaluation method steps are as follows: A. Test system: starting from the sensor, which can be an accelerometer, a speedometer, or the position determined by satellite GPS and Beidou, analyze the amplitude time spectrum and the corresponding edge spectrum of the acceleration through the Hilbert-Huang transform, and convert the The edge spectrum is compared to some existing spectrum of healthy structures to determine the presence of frequency peak screening, broadening, and to determine the presence and severity of damage; B. Determine the relative stiffness of any given structure to its intact counterpart by inferring stiffness changes from frequency ratios; C. The frequency can also be derived from the position determined by satellite GPS and Beidou or speedometer, vibration can be caused by artificial load or environmental forcing, such as wind or micro-seismic, wind (in the case of windmills), traffic (in the case of bridges), accelerometer data Instantaneous frequency can be obtained by HHT analysis; D. Any damage to the foundations or piles by piers and towers through scouring or any other cause will make the structure less rigid, and it can also be demonstrated that the vibration frequencies of the cantilever beam are as follows:

D1, where E is the modulus of elasticity of the beam material, I is the moment of inertia of the beam cross-section, M, mass and L, the length of the beam, in short, EI/ML4 can be considered as the stiffness S of the structure, any weak point in the anchoring of the beam or the scour exposure of the pile will result in a higher L value, which will also result in a lower vibration frequency; D2. Its presence and location are determined by testing at each site, and severity can be determined by relative stiffness changes relative to the intact state or intact state; D3. Alternatively, the presence and severity of damage may be determined by the loading conditions, light loads may not show any damage, but heavy loads will show any damage; D4. Only heavy load can push the stress-strain curve to the nonlinear range, resulting in nonlinear vibration waveform, and the frequency downshift means the danger of permanent damage; E. Pier 1 is intact, while pier 2 has been scoured, and the ratio of frequency and stiffness is as follows:

E1. Therefore, the damage to pier #2 by the frequency change is obvious and severe, as the stiffness ratio drops by nearly 50% (9 to 16); E2. For bridge piers, various loads, especially light loads and heavy loads, can also be used as tests. According to the calculated nonlinearity, it can be shown that the structure is entering a nonlinear state, which usually indicates overloading. Frequency downshift is a clear indication of damage. and shall be marked; F. Acceleration records are obtained in mixed light and heavy traffic, for relatively heavy loads of cc020 loads it is easy to see peak broadening, which indicates the need for caution, safety, caution or danger criteria in which damage is also identified The severity is determined according to the table given: S=f/fo=To/T Frequency of the first mode the period of the first mode; 0.85s 1 safe 0.70s < 0.85 warning S<0.70 requires detailed inspection; now (broken) vs used (not broken) 0.90s 1 safe 0.80s < 0.90 warning S<0.80 requires detailed examination. 2. The method for monitoring and evaluating infrastructure foundation safety according to claim 1, characterized in that: the stiffness change in the step B is measured by an accelerometer connected to the structure to be inspected, and should be measured by a Hilbert- Huang Analytics analyzes the data. 3. The infrastructure foundation safety monitoring and evaluation method according to claim 1, characterized in that: in the step D, the vibration of the bridge pier and the tower can be regarded as a cantilever beam anchored on the base or as a foundation pile. extend. 4. The infrastructure foundation safety monitoring and evaluation method according to claim 1, characterized in that: in the step D1, the square of the frequency is proportional to the stiffness, and the change of the vibration frequency is used to judge the integrity of the structure, and the change of the frequency Can be used as a measure of damage. 5 . The method for monitoring and evaluating infrastructure foundation safety according to claim 1 , wherein in the step E1 , a heavy load may cause nonlinear vibration, and a light load may cause linear vibration. 6 . 6 . The method for monitoring and evaluating the security of infrastructure bases according to claim 1 , wherein the frequency peak broadening in the step D4 is close to a non-linear range. 7 . 7. The infrastructure foundation safety monitoring and evaluation method according to claim 1, characterized in that: in said step F, an acceleration record is obtained in mixed light-load and heavy-load traffic, and the corresponding Hilbert-Huang transform is calculated. edge spectrum.