A Site Seismic Delineation Method Based on the Correlation between Static Penetration Testing and Shear Wave Velocity

Abstract

This invention belongs to the technical field of geotechnical engineering and earthquake engineering, and provides a site seismic delineation method based on the correlation between static cone penetration test (CPT) and shear wave velocity, fully combining CPT and V s The advantages of the two testing methods are that by introducing characteristic parameters reflecting the degree of soil aging, a more reasonable classification of seismic sites can be achieved, thereby improving the scientific nature of site classification and the reliability of seismic design. The method includes the following steps: S1, in-situ test data acquisition, including static cone penetration test and shear wave velocity test; S2, parameter normalization processing, calculating normalized cone tip resistance and normalized shear wave velocity, and then introducing soil classification index to obtain the normalized cone tip resistance of equivalent pure sand; S3, establishing the correlation between benchmark static cone penetration test and shear wave velocity; S4, determining the soil geological age aging factor; S5, constructing a comprehensive site seismic classification index; S6, site seismic category classification; S7, engineering application and result output.

Description

Technical Field

[0001] This invention relates to a site seismic classification method based on the correlation between static cone penetration and shear wave velocity, belonging to the technical fields of geotechnical engineering and earthquake engineering. Background Technology

[0002] Seismic site classification is a crucial foundational task in seismic design and seismic hazard assessment, and its results directly affect the selection of seismic motion parameters and the safety of engineering structures. Currently, in engineering practice, methods based on the Standard Penetration Test (SPT) or shear wave velocity (V0) are commonly used. s The site classification method is as follows. However, the dynamic response characteristics of actual soil are not only related to soil type and stress state, but also significantly affected by soil formation history and evolution process, i.e., the geological age of soil (soil aging effect).

[0003] Studies have shown that natural sedimentary soils gradually improve in structure, cementation, and low-strain stiffness over long geological periods and environmental influences, thereby enhancing their resistance to liquefaction. However, current site classification methods typically do not explicitly consider the geological age of soils, which can easily lead to misjudgments of the site conditions of older soils, resulting in overestimation of seismic liquefaction potential or unreasonable site classification.

[0004] Static cone penetration test (CPT) reflects the penetration resistance characteristics of soil under relatively large strain conditions, while shear wave velocity test (V... s The strain level difference between CPT-V and CPT-V represents the dynamic stiffness characteristics of soil under low strain conditions. This difference provides a physical basis for identifying soil aging effects. However, current technology lacks a method based on CPT-V. s A coupling relationship, a method that can quantitatively reflect the effects of soil aging and be used for seismic site classification.

[0005] Therefore, there is an urgent need to propose a method based on CPT-V. s A site seismic delineation method that considers the geological age effect can fully combine CPT and V. s The advantages of both testing methods are that they effectively reflect the dynamic response characteristics and provide a scientific basis for the seismic safety assessment and design of the site. Summary of the Invention

[0006] This invention overcomes the shortcomings of existing technologies, and the technical problem it aims to solve is: to provide a site seismic delineation method based on the correlation between static penetration testing and shear wave velocity, fully combining CPT and V s The advantages of both testing methods are that by introducing characteristic parameters that reflect the degree of soil aging, a more reasonable classification of seismic sites can be achieved, thereby improving the scientific nature of site classification and the reliability of seismic design.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a site seismic delineation method based on the correlation between static cone penetration and shear wave velocity, comprising the following steps:

[0008] S1. Acquisition of in-situ test data, including static cone penetration test and shear wave velocity test;

[0009] S2. Parameter normalization processing: calculate the normalized cone tip resistance and normalized shear wave velocity, and then introduce the soil classification index to obtain the equivalent pure sand normalized cone tip resistance.

[0010] S3. Establish the correlation between the benchmark static penetration test and the shear wave velocity;

[0011] S4. Determine the geological age aging factors of the soil.

[0012] S5. Construction of comprehensive site seismic classification index;

[0013] S6. Site seismic classification;

[0014] S7. Engineering Applications and Result Output.

[0015] The in-situ test data acquisition in step S1 specifically involves:

[0016] Test points were set up at the site to be evaluated, and static cone penetration tests and shear wave velocity tests were carried out to obtain raw test data at different depths, including the measured cone tip resistance q. c Side wall friction f s and shear wave velocity V s Simultaneously record the total overburden stress at the corresponding depth. and effective overburden stress .

[0017] The parameter normalization process in step S2 is specifically as follows:

[0018] The obtained static cone penetration test and shear wave velocity raw test data were subjected to stress normalization, and the normalized cone tip resistance Q was calculated. cn and normalized shear wave velocity V s1 Then, the soil classification index is introduced to Q. cn Further modifications yielded the equivalent pure sand normalized cone tip resistance Q. cn,cs ;

[0019] The normalized cone tip resistance Q cn The expression is:

[0020] (1);

[0021] Where, q c To measure the resistance at the cone tip; and These are the total overburden stress and the effective overburden stress, respectively.

[0022] The normalized shear wave velocity V s1 The expression is:

[0023] (2);

[0024] Among them, V s p is the shear wave velocity; a For reference pressure, p a =0.1 MPa; To effectively cover stress;

[0025] The equivalent pure sand normalized cone tip resistance Q cn,cs The expression is:

[0026] Q cn,cs =k c* Q cn (3);

[0027] Among them, Q cn Normalized cone tip resistance; k c This is the fine-grain correction factor;

[0028] Fine-grained correction factor k c With soil index I c Related:

[0029] (4);

[0030] Among them, Q cn Normalized cone tip resistance; F r Friction ratio;

[0031] F r =f s / ( )×100% (5);

[0032] Among them, f s q represents the sidewall frictional resistance. c To measure the resistance at the cone tip; Total overburden stress;

[0033] If I c When k ≤ 1.64 c =1.0;

[0034] If I c When >1.64, ;

[0035] The corresponding k c Substituting into Formula 3, we can normalize the cone tip resistance Q.cn Calculate the equivalent pure sand normalized cone tip resistance Q. cn,cs .

[0036] The establishment of the correlation between the benchmark static cone penetration test and the shear wave velocity in step S3 is specifically as follows:

[0037] Q based on normalized parameters cn,cs With V s1 Data, established in a double logarithmic coordinate system, CPT–V s The empirical correlation, expressed in power function form, is as follows:

[0038] (6);

[0039] Among them, V s1 For normalized shear wave velocity; Q tn,cs The normalized cone tip resistance is for equivalent pure sand; a is the empirical proportionality coefficient; b is the power coefficient.

[0040] After performing a natural logarithmic transformation on this relation, we obtain... – The linear relationship:

[0041] (7).

[0042] The determination of the soil geological age aging factor in step S4 specifically involves:

[0043] exist – In the coordinate system, a linear fit is performed on the measured data to obtain the intercept term lna of the fitted line, and the intercept term is defined as the geological time factor K. a It is used to quantitatively characterize the effect of improved small-strain stiffness properties of soil caused by long-term sedimentary evolution, structural enhancement, and cementation:

[0044] (8);

[0045] Among them, K a The logarithmic form of the empirical proportionality constant a, i.e., lna, is given by K. a Also primarily influenced by the geological age of the soil, a geological age factor K was established for further verification. a The continuous relationship between time t and time t is expressed as:

[0046] (9);

[0047] Where c is the geological time factor K aThe slope of the logarithmic time change is used to characterize the degree of influence of geological age growth on soil structural stability and the rate of aging effect enhancement; d is the intercept, which represents the initial geological age factor of the soil under the reference time condition (t=1), reflecting the initial structural state and sedimentary characteristics of the soil.

[0048] The construction of the comprehensive site seismic classification index in step S5 is specifically as follows:

[0049] At a shear wave velocity V s Or the weighted average value of soil shear wave velocity within 30m below the surface, V s30 In the site seismic classification index system, the geological time factor K is introduced. a Correcting the dynamic characteristics of the site, in V s1 -Q tn,cs In coordinate space, joint K a The contour lines of the indicators form a comprehensive site discrimination index method that simultaneously reflects the small strain, large strain characteristics and geological age effects of the soil.

[0050] The weighted average value of soil shear wave velocity within 30m below the surface, V s30 Represented as:

[0051] (10);

[0052] Among them, h i V represents the thickness of the iiith soil layer, in meters. s,i denoted as , where is the shear wave velocity of the i-th soil layer, in m / s; and n is the number of soil layers within a 30 m range.

[0053] The site seismic classification in step S6 is specifically as follows:

[0054] Based on the comprehensive site discrimination index, the site is classified into seismic site categories to distinguish the different seismic response characteristics of recently deposited sandy soils, Holocene sandy soils, and Pleistocene sandy soils.

[0055] The engineering application and result output of step S7 are as follows:

[0056] The site seismic classification results are applied to the selection of ground motion parameters, seismic design, and liquefaction risk zoning, and the corresponding site categories, aging factor distributions, and corrected seismic response characteristic parameters are output.

[0057] Compared with the prior art, the present invention has the following advantages:

[0058] 1. Using CPT and V s The complementary properties of different strain levels enable explicit identification of soil aging effects;

[0059] 2. To avoid misclassification of site categories caused by neglecting soil aging in traditional site classification methods;

[0060] 3. No detailed geological age or sedimentary history information is required, making it highly applicable to engineering projects;

[0061] 4. It can provide a more reasonable and reliable technical basis for seismic site classification, liquefaction risk assessment and seismic design. Attached Figure Description

[0062] The present invention will now be described in further detail with reference to the accompanying drawings;

[0063] Figure 1 This is a schematic diagram of the steps of the present invention;

[0064] Figure 2 The Holocene sand, young Holocene sand, and Pleistocene sand in this invention and Correlation curve;

[0065] Figure 3 This invention is used to determine the geological time factor K based on time. a The curve;

[0066] Figure 4 This is an example of site category classification and geological age boundary curve in an embodiment of the present invention;

[0067] Figure 5 These are three regions based on the uncertainty of soil geological age in the embodiments of the present invention. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments; based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] like Figure 1 As shown, the present invention provides a site seismic delineation method based on the correlation between static cone penetration and shear wave velocity, comprising the following steps:

[0070] S1. Acquisition of in-situ test data, including static cone penetration test and shear wave velocity test;

[0071] S2. Parameter normalization processing: calculate the normalized cone tip resistance and normalized shear wave velocity, and then introduce the soil classification index to obtain the equivalent pure sand normalized cone tip resistance.

[0072] S3. Establish the correlation between the benchmark static penetration test and the shear wave velocity;

[0073] S4. Determine the geological age aging factors of the soil.

[0074] S5. Construction of comprehensive site seismic classification index;

[0075] S6. Site seismic classification;

[0076] S7. Engineering Applications and Result Output.

[0077] The in-situ test data acquisition in step S1 specifically involves:

[0078] Test points were set up at the site to be evaluated, and static cone penetration tests (CPT) and shear wave velocity tests (V) were conducted respectively. s (), to obtain raw test data within different depth ranges, including the measured cone tip resistance q c Side wall friction f s and shear wave velocity V s Simultaneously record the total overburden stress at the corresponding depth. and effective overburden stress .

[0079] The parameter normalization process in step S2 is specifically as follows:

[0080] The obtained static cone penetration test and shear wave velocity raw test data were subjected to stress normalization, and the normalized cone tip resistance Q was calculated. cn and normalized shear wave velocity V s1 Then, the soil classification index is introduced to Q. cn Further modifications yielded the equivalent pure sand normalized cone tip resistance Q. cn,cs This is used to eliminate the influence of overburden pressure and to characterize the mechanical properties of soil under large and small strain conditions, so that data from different depths and different site conditions are comparable.

[0081] The normalized cone tip resistance Q cn The expression is:

[0082] (1);

[0083] Where, q c To measure the resistance at the cone tip; and These are the total overburden stress and the effective overburden stress, respectively.

[0084] The normalized shear wave velocity V s1 The expression is:

[0085] (2);

[0086] Among them, V s p is the shear wave velocity; a For reference pressure, p a =0.1 MPa; To effectively cover stress;

[0087] The equivalent pure sand normalized cone tip resistance Q cn,cs The expression is:

[0088] Q cn,cs =k c* Q cn (3);

[0089] Among them, Q cn Normalized cone tip resistance; k c This is the fine-grain correction factor;

[0090] Fine-grained correction factor k c With soil index I c Related:

[0091] (4);

[0092] Among them, Q cn Normalized cone tip resistance; F r Friction ratio;

[0093] F r =f s / ( )×100% (5);

[0094] Among them, f s q represents the sidewall frictional resistance. c To measure the resistance at the cone tip; Total overburden stress;

[0095] If I c When k ≤ 1.64 c =1.0;

[0096] If I c When >1.64, ;

[0097] The corresponding k c Substituting into Formula 3, we can normalize the cone tip resistance Q. cn Calculate the equivalent pure sand normalized cone tip resistance Q. cn,cs .

[0098] Normalized cone tip resistance Q cnThe cone tip resistance parameter after stress normalization reflects the shear strength and stiffness characteristics of the soil under in-situ stress, and is still affected by the fine particle content of the soil.

[0099] Equivalent pure sand normalized cone tip resistance Q cn,cs : is in Q cn Based on this, the corrected parameters obtained after further eliminating the influence of soil particle size composition (especially fine content) are used to unify the comparative analysis under different soil types.

[0100] The establishment of the correlation between the benchmark static cone penetration test and the shear wave velocity in step S3 is specifically as follows:

[0101] Q based on normalized parameters cn,cs With V s1 Data, established in a double logarithmic coordinate system, CPT–V s The empirical correlation, expressed in power function form, is as follows:

[0102] (6);

[0103] Among them, V s1 For normalized shear wave velocity; Q tn,cs The normalized cone tip resistance is for equivalent pure sand; a is the empirical proportionality coefficient; b is the power coefficient.

[0104] After performing a natural logarithmic transformation on this relation, we obtain... – The linear relationship:

[0105] (7).

[0106] The determination of the soil geological age aging factor in step S4 is specifically as follows:

[0107] exist – In the coordinate system, a linear fit is performed on the measured data to obtain the intercept term lna of the fitted line, and the intercept term is defined as the geological time factor K. a It is used to quantitatively characterize the effect of improved small-strain stiffness properties of soil caused by long-term sedimentary evolution, structural enhancement, and cementation:

[0108] (8);

[0109] Among them, K a K is the logarithmic form of the empirical proportionality constant a, therefore K a Also primarily influenced by the geological age of the soil, a geological age factor K was established for further verification. a The continuous relationship between time t and time t is expressed as:

[0110] (9);

[0111] Where c is the geological time factor K a The slope of the logarithmic time change is used to characterize the degree of influence of geological age growth on soil structural stability and the rate of aging effect enhancement; d is the intercept, which represents the initial geological age factor of the soil under the reference time condition (t=1), reflecting the initial structural state and sedimentary characteristics of the soil.

[0112] The construction of the comprehensive site seismic classification index in step S5 is specifically as follows:

[0113] At a shear wave velocity V s Or the weighted average value of soil shear wave velocity within 30m below the surface, V s30 In the site seismic classification index system, the geological time factor K is introduced. a Correcting the dynamic characteristics of the site, in V s1 -Q tn,cs In coordinate space, joint K a The contour lines of the index form a pattern that simultaneously reflects small soil strains (by V). s1 Reflection), large strain characteristics (by Q) tn,cs (reflection) and geological age effects (by K) a The comprehensive site discrimination index method reflects the seismic site classification of the site. Based on this comprehensive index, the different seismic response characteristics of old sandy soil and newly deposited sandy soil can be effectively distinguished.

[0114] The weighted average value of soil shear wave velocity within 30m below the surface, V s30 Represented as:

[0115] (10);

[0116] Among them, h i V represents the thickness of the iiith soil layer, in meters. s,i denoted as , where is the shear wave velocity of the i-th soil layer, in m / s; and n is the number of soil layers within a 30 m range.

[0117] The site seismic classification in step S6 is specifically as follows:

[0118] Based on the comprehensive site discrimination index, the site is classified into seismic site categories to distinguish the different seismic response characteristics of recently deposited sandy soils, Holocene sandy soils, and Pleistocene sandy soils, thus avoiding misclassification of site categories due to neglecting the geological age effect of the soil.

[0119] The engineering application and result output of step S7 are as follows:

[0120] The site seismic classification results are applied to the selection of ground motion parameters, seismic design and liquefaction risk zoning, and the corresponding site categories, aging factor distribution and corrected seismic response characteristic parameters are output. This is of great significance for the evaluation and design of the foundation seismic safety of actual projects, and can provide a scientific basis for seismic reinforcement design, project site selection and construction scheme optimization.

[0121] The steps of the present invention will be described in detail below with reference to the data from the embodiments.

[0122] Specifically, in one embodiment of the present invention: before conducting liquefaction potential analysis in a seismic zone, it is first necessary to classify the site according to seismic conditions to reasonably characterize the seismic motion amplification or attenuation characteristics of the site. This embodiment is based on the shear wave velocity (V0) widely used in current engineering practice. s The site classification concept, combined with the geological age factor K proposed in this invention, is applied. a This study aims to improve and validate traditional site classification methods.

[0123] In this embodiment, the site seismic classification references the NEHRP site classification system, which is based on the site's equivalent shear wave velocity (the weighted average of soil shear wave velocities within 30m below the surface). S30 Soil masses are classified into six categories, A through F (Table 1), to reflect the seismic response characteristics under different site conditions. Although the NEHRP standard uses the uncorrected shear wave velocity V... s As a basis for classification, but in this embodiment, the stress-corrected shear wave velocity V is introduced. s1 As an auxiliary analysis parameter, the focus is on analyzing the impact of soil aging on site classification results, rather than providing a single classification conclusion for a single engineering site.

[0124] Table 1. Site seismic classification based on NEHRP (BSSC, 2001)

[0125]

[0126] For multiple sites, a large number of normalized parameters Q can be obtained from both measured and calculated data based on steps S1 and S2. cn,cs With V s1 The actual measurement results of the selected site in this embodiment are shown in Table 2.

[0127] Table 2 Test data and normalized data for a certain site

[0128]

[0129] Based on this data, relational fitting can be performed. For example... Figure 2As shown, CPT-V, suitable for Holocene clean sand, was selected. s Using empirical relationships as a benchmark model, a normalized shear wave velocity V is established. s1 Normalized cone tip resistance Q of equivalent pure sand cn,cs The power function relationship between them:

[0130] ;

[0131] Normalized cone tip resistance Q of equivalent pure sand cn,cs With normalized shear wave velocity V s1 In a two-dimensional coordinate system, experimental data of Holocene, Pleistocene, and Young Holocene sands (represented by the Canterbury area) were compared and analyzed. The results show that the three types of sands with different origins and geological ages exhibit different characteristics in Q... tn,cs -V s1 The same mathematical function can be used to uniformly describe all spatial elements, and this relationship is also applicable to Pleistocene sandy soils and young Holocene sandy soils.

[0132] Under the condition that the power exponent coefficient b remains constant (b=0.231), the empirical proportionality coefficient a of sandy soils from different geological ages shows significant differences. The Pleistocene sandy soil has the largest a value, followed by the Holocene sandy soil, while the young Holocene sandy soil has the smallest a value. These results indicate that the geological age effect of soil is mainly reflected by the change in the empirical proportionality coefficient a, while the power exponent coefficient b is relatively stable for sandy soils of different ages.

[0133] Based on the normalized cone tip resistance Q of equivalent pure sand cn,cs With normalized shear wave velocity V s1 In a two-dimensional coordinate space, taking the logarithm of equation (6) transforms it into a linear form, and then CPT-V s The correlation is expressed as a linear relationship. Define the geological time factor (denoted as K). a )for – Intercept in a relation:

[0134] ;

[0135] Equation (7) shows that K a K is the logarithmic form of the empirical proportionality constant a, therefore K a Also primarily influenced by the geological age of the soil, further establishing the geological age factor K a Continuous relationship with time t Figure 3 ):

[0136] ;

[0137] The mean geological age of soil is defined as follows: for sites that have not experienced liquefaction, it refers to the time from the formation of the sandy soil during deposition to the time of in-situ testing; for sites that have experienced liquefaction, it refers to the time from the most recent liquefaction event to the time of in-situ testing (also known as "reset age"). Figure 3 As shown, the geological time factor K a Overall, K increases with soil age, although some dispersion exists. Existing studies indicate that sandy soils deposited less than 500 years ago have high liquefaction sensitivity; Holocene sandy soils (<10,000 years) have moderate to high liquefaction sensitivity; while Pleistocene sandy soils (10,000 to 1.8 million years) have relatively low liquefaction sensitivity. Corresponding to these characteristics, when the soil age is approximately 500 years and 10,000 years, K... a Typical values ​​are approximately 4.25 and 4.35, respectively.

[0138] Further analysis shows that when using recalculated ages for characterization, the experimental data distribution is relatively concentrated; however, when using initial depositional ages, the data dispersion increases significantly, indicating that liquefaction events have a "recalculation" effect on the aging process of sandy soils. Some of the dispersion differences may stem from soil age estimation errors or experimental disturbances. Based on the above analysis, compared to extrapolating based on assumed depositional ages, directly determining the geological age factor K using in-situ test parameters is a more effective approach. a .

[0139] The geological age factor K was calculated based on the aforementioned methods and steps. a In this embodiment, K is taken as a ≈4.35 is used as an empirical boundary value between Holocene and Pleistocene sands; when K a When the temperature is less than 4.25, sandy soils exhibit strong liquefaction sensitivity. Figure 4 A V-based s1 The NEHRP site category boundaries are shown as horizontal dashed lines, and the CPT–V corresponding to Holocene and Pleistocene sands are also plotted. s Correlation curve.

[0140] Based on the aforementioned comprehensive discrimination index and combined with the NEHRP site classification standard, seismic site classification is performed when Q cn,cs When the soil size is large, the site category is consistently classified as D, with a weak correlation to soil age; in medium-sized areas, the site category is classified as Q. cn,cs Within the interval, if the soil age effect is ignored, only the CPT-V established based on Holocene sandy soil is used. s The relationship between these factors can easily lead to an overestimation of the site classification of Pleistocene sandy soils; while in low Q... cn,csWithin the interval, the site categories are mainly E or F, with little influence from soil age. Based on this comprehensive index, seismic site classification can effectively distinguish the different seismic response characteristics of old sandy soils and recently deposited sandy soils.

[0141] Since the initial classification of seismic site categories was based on shear wave velocity, the analysis assumed that shear wave velocity could accurately reflect the seismic site classification results. The analysis shows that the younger the soil age (i.e., the smaller the geological age factor K), the more accurate the classification. a The lower the K value, the higher the probability that it will be classified as a Class E or Class F site. For example, sandy sediments in the Canterbury region of New Zealand that have undergone a seismic sequence have a K value that is... a ≈ 4.0, under which the corresponding seismic site category is either E or F.

[0142] For some engineering projects with low to moderate seismic fortification requirements, the engineering survey phase may only obtain static cone penetration test (CPT) results, lacking direct shear wave velocity test data. In such cases, it is usually necessary to use CPT-V... s Empirical correlation with shear wave velocity V s Inversion estimation is performed. However, due to the significant differences in small strain stiffness between sands from different sedimentary ages, neglecting soil aging effects may introduce significant classification uncertainty near site category boundaries.

[0143] The shear wave velocity V obtained based on CPT inversion s1 Compared with V s1 A comparative analysis of site category boundaries reveals that the traditional CPT–Vs empirical relationship, without considering the geological age effect of the soil, is insufficient to accurately reflect the true site category. In contrast, the method of this invention introduces a geological age factor K. a Correcting the shear wave velocity can effectively reduce the uncertainty caused by soil aging effects and improve the rationality and consistency of site classification results.

[0144] Figure 5 These are three regions based on the uncertainty of soil geological age in embodiments of the present invention. For example... Figure 5 As shown, the uncertainty in seismic site classification caused by soil geological age effects can be corrected based on the CPT cone resistance parameter Q. cn,cs The site is divided into Zone I, Zone II, and Zone III. Zone III (Q cn,cs Within ≥175), regardless of the age of sand deposition, the site category is consistently classified as Class D, exhibiting minimal uncertainty in classification; Region I (Q cn,csWithin region ≤25), the site is consistently classified as a weak site of type E or F, unaffected by soil age; while in region II (25≤Q)... cn,cs Within the range of ≤175, site grading is highly sensitive to soil aging effects. When CPT-V is used based on different geological age assumptions... s When using correlations, site classification biases may occur. Specifically, using correlations based on Holocene sands may overestimate the site classification of Pleistocene sands, while using correlations based on Pleistocene sands may underestimate the site classification of Holocene sands, thus leading to misclassification of sites.

[0145] The site classification results obtained based on the method of this invention were applied to the selection of seismic motion parameters and the analysis of liquefaction potential. The results showed that: old sandy soil sites exhibited higher liquefaction resistance and stiffness response; the liquefaction sensitivity of recently deposited sandy soils was significantly enhanced; and the corrected site classification results had better consistency with the actual seismic response and observation phenomena.

[0146] The above embodiments demonstrate that the site seismic classification method based on the correlation between static cone penetration and shear wave velocity proposed in this invention can effectively identify the classification uncertainty caused by neglecting the geological age effect of soil near the site category boundary in traditional site classification methods, thereby improving the rationality, reliability and engineering applicability of seismic site classification results.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A site seismic delineation method based on the correlation between static cone penetration and shear wave velocity, characterized in that, Includes the following steps: S1. Acquisition of in-situ test data, including static cone penetration test and shear wave velocity test; S2. Parameter normalization processing: calculate the normalized cone tip resistance and normalized shear wave velocity, and then introduce the soil classification index to obtain the equivalent pure sand normalized cone tip resistance. S3. Establish the correlation between the benchmark static penetration test and the shear wave velocity; S4. Determine the geological age aging factors of the soil. S5. Construction of comprehensive site seismic classification index; S6. Site seismic classification; S7. Engineering Applications and Result Output.

2. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 1, characterized in that, The in-situ test data acquisition in step S1 specifically involves: Test points were set up at the site to be evaluated, and static cone penetration tests and shear wave velocity tests were carried out to obtain raw test data at different depths, including the measured cone tip resistance q. c Side wall friction f s and shear wave velocity V s Simultaneously record the total overburden stress at the corresponding depth. and effective overburden stress .

3. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 2, characterized in that, The parameter normalization process in step S2 is specifically as follows: The obtained static cone penetration test and shear wave velocity raw test data were subjected to stress normalization, and the normalized cone tip resistance Q was calculated. cn and normalized shear wave velocity V s1 Then, the soil classification index is introduced to Q. cn Further modifications yielded the equivalent pure sand normalized cone tip resistance Q. cn,cs ; The normalized cone tip resistance Q cn The expression is: （1）； Where, q c To measure the resistance at the cone tip; and These are the total overburden stress and the effective overburden stress, respectively. The normalized shear wave velocity V s1 The expression is: （2）； Among them, V s p is the shear wave velocity; a For reference pressure, p a =0.1 MPa; To effectively cover stress; The equivalent pure sand normalized cone tip resistance Q cn,cs The expression is: Q cn,cs =k c* Q cn (3); Among them, Q cn Normalized cone tip resistance; k c This is the fine-grain correction factor; Fine-grained correction factor k c With soil index I c Related: （4）； Among them, Q cn Normalized cone tip resistance; F r Friction ratio; F r =f s / ( )×100% (5); Among them, f s q represents the sidewall frictional resistance; c To measure the resistance at the cone tip; This represents the total overburden stress. If I c When k ≤ 1.64 c =1.0; If I c When >1.64, ; The corresponding k c Substituting into Formula 3, we can normalize the cone tip resistance Q. cn Calculate the equivalent pure sand normalized cone tip resistance Q. cn,cs .

4. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 3, characterized in that, The establishment of the correlation between the benchmark static cone penetration test and the shear wave velocity in step S3 is specifically as follows: Q based on normalized parameters cn,cs With V s1 Data, established in a double logarithmic coordinate system, CPT–V s The empirical correlation, expressed in power function form, is as follows: （6）； Among them, V s1 Q represents the normalized shear wave velocity. tn,cs The normalized cone tip resistance is for equivalent pure sand; a is the empirical proportionality coefficient; b is the power coefficient. After performing a natural logarithmic transformation on this relation, we obtain... – The linear relationship: （7）。 5. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 4, characterized in that, The determination of the soil geological age aging factor in step S4 specifically involves: exist – In the coordinate system, a linear fit is performed on the measured data to obtain the intercept term lna of the fitted line, and the intercept term is defined as the geological time factor K. a It is used to quantitatively characterize the effect of improved small-strain stiffness properties of soil caused by long-term sedimentary evolution, structural enhancement, and cementation: （8）； Among them, K a The logarithmic form of the empirical proportionality constant a, i.e., lna, is given by K. a Also primarily influenced by the geological age of the soil, a geological age factor K was established for further verification. a The continuous relationship between time t and time t is expressed as: （9）； Where c is the geological time factor K a The slope of the logarithmic time change is used to characterize the degree of influence of geological age growth on soil structural stability and the rate of aging effect enhancement; d is the intercept, which represents the initial geological age factor of the soil under the reference time condition (t=1), reflecting the initial structural state and sedimentary characteristics of the soil.

6. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 5, characterized in that, The construction of the comprehensive site seismic classification index in step S5 is specifically as follows: At the shear wave velocity V s Or the weighted average value of soil shear wave velocity within 30m below the surface, V s30 In the site seismic classification index system, the geological time factor K is introduced. a Correcting the dynamic characteristics of the site, in V s1 -Q tn,cs In coordinate space, joint K a The contour lines of the indicators form a comprehensive site discrimination index method that simultaneously reflects the small strain, large strain characteristics and geological age effects of the soil. The weighted average value of soil shear wave velocity within 30m below the surface, V s30 Represented as: （10）； Among them, h i V represents the thickness of the iiith soil layer, in meters. s,i denoted as , where is the shear wave velocity of the i-th soil layer, in m / s; and n is the number of soil layers within a 30 m range.

7. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 6, characterized in that, The site seismic classification in step S6 is specifically as follows: Based on the comprehensive site discrimination index, the site is classified into seismic site categories to distinguish the different seismic response characteristics of recently deposited sandy soils, Holocene sandy soils, and Pleistocene sandy soils.

8. The site seismic delineation method based on the correlation between static cone penetration and shear wave velocity as described in claim 7, characterized in that, The engineering application and result output of step S7 are as follows: The site seismic classification results are applied to the selection of ground motion parameters, seismic design, and liquefaction risk zoning, and the corresponding site categories, aging factor distributions, and corrected seismic response characteristic parameters are output.

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