Anti-seismic parameter-oriented method and system for accurately obtaining undisturbed rock-soil drilling samples

Abstract

This invention relates to the field of geotechnical engineering investigation and undisturbed sampling technology, and discloses a method for accurately obtaining undisturbed soil samples from boreholes guided by seismic parameters. The method includes the following steps: S1, Exploration data acquisition and identification of key seismic layers: Acquire geotechnical engineering investigation data of the target site. Based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one key seismic soil layer that has a controlling effect on the site's seismic response. By constructing a multi-parameter fusion rule base for identifying key seismic soil layers, the automatic identification and location of liquefaction layers, weak layers, and wave velocity interface layers that have a controlling effect on the site's seismic response are achieved. Based on the identification results, the sampling location is dynamically planned to ensure that the sampling range fully covers the top, bottom, and middle sections of the key layer, avoiding the omission of key features due to sampling location deviations in traditional methods. This ensures that the obtained undisturbed soil samples can truly reflect the engineering characteristics of the site's weak points in seismic resistance.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering investigation and undisturbed sampling technology, specifically to a method and system for accurately obtaining undisturbed samples from geotechnical boreholes guided by seismic parameters. Background Technology

[0002] In geotechnical engineering investigation, obtaining high-quality undisturbed soil samples is the foundation for accurately evaluating the site's engineering geological conditions and seismic performance. Traditional sampling methods usually involve core sampling at equal intervals or based on empirical judgment, failing to focus on key soil layers that have a controlling effect on the site's seismic response, resulting in insufficient representativeness and completeness of the obtained samples.

[0003] Existing technology 1: Conventional uniform sampling method. This method takes samples at fixed intervals during drilling. Although it is simple to operate, it cannot ensure the coverage of key seismic layers such as liquefaction layers and weak layers. The sampling location is often deviated from the key layer, and the choice of soil sampler is limited, making it difficult to adapt to the sampling requirements of different soil layers. This results in large sample disturbance, distortion of mechanical parameters, and affects the accuracy of subsequent seismic analysis.

[0004] Existing technology 2: Manual experience-guided sampling method. This method relies on engineers' experience to judge key layers and conduct sampling. Although it has a certain degree of targeting, it lacks systematic and rule-based identification criteria. The selection of sampling locations and equipment is highly subjective and is not combined with information technology. The sample information is not fully recorded, and the traceability is poor, making it difficult to meet the requirements of modern geotechnical engineering data management and verification. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for accurately obtaining undisturbed samples from rock and soil boreholes guided by seismic parameters, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for accurately obtaining undisturbed samples from soil and rock boreholes guided by seismic parameters, comprising the following steps:

[0007] S1. Exploration data acquisition and identification of key seismic layers: acquire geotechnical engineering investigation data of the target site, and based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one key seismic soil layer that has a controlling effect on the seismic response of the site.

[0008] S2. Dynamic design of drilling parameters: Based on the location and thickness of the identified key seismic soil layers, the drilling depth, core sampling location and core sampling tool specifications are dynamically planned so that the planned core sampling location at least covers the top slab, bottom slab and middle area of ​​the key seismic soil layers.

[0009] S3. Guided drilling and undisturbed sampling: When drilling is performed, switch to low-disturbance drilling mode when the drilling depth is close to the planned core sampling position. Use core sampling tools that match the specifications of the undisturbed soil sample to perform indentation or impact sampling at the planned position of the key seismic soil layer to obtain undisturbed soil and rock samples.

[0010] S4. Sample Packaging and Information Association: The obtained undisturbed soil and rock samples are sealed on-site and a unique identification code is generated; the unique identification code is associated and stored with the three-dimensional coordinates of the core sampling location, the corresponding key seismic soil layer number, and the exploration data.

[0011] As a preferred technical solution of the present invention, the identification and location of key seismic soil layers in step S1 includes: automatically analyzing the standard penetration test blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit and soil profile information in the input survey data according to the preset key seismic soil layer identification rule library.

[0012] The recognition rule base contains multiple layers of judgment rules, including at least:

[0013] The first layer is the liquefaction potential determination rule: used to identify saturated cohesive-free soil layers where pore water pressure may increase significantly under seismic action;

[0014] The second layer consists of rules for determining weak characteristics: used to identify weak cohesive soil layers with low shear strength and high compressibility;

[0015] The third layer is the wave velocity interface determination rule: used to identify wave velocity interface layers where there are significant differences in shear wave velocities between adjacent soil layers;

[0016] Output the soil layers that satisfy any of the judgment rules as the key soil layers for seismic resistance, and record their type, depth range and core discrimination index.

[0017] As a preferred technical solution of the present invention, the liquefaction potential determination rule is based on a set of preset threshold values ​​that are associated with soil depth and site design ground motion parameters. The liquefaction potential determination rule includes: comparing the measured value of the standard penetration test blow count of the soil layer obtained by the survey with the preset threshold at the corresponding depth. If the measured value is less than the threshold, the soil layer is determined to be a key seismic soil layer with liquefaction potential.

[0018] As a preferred technical solution of the present invention, the specifications of the core sampling device in step S2 are as follows: select the type, diameter and area ratio of the soil sampler according to the type of the key seismic soil layer;

[0019] For soil layers identified by the first or second layer determination rules, use thin-walled soil samplers with an area ratio of less than 15%.

[0020] For soil layers or harder soil layers identified by the third-layer determination rule, a double-tube soil sampler should be selected.

[0021] As a preferred technical solution of the present invention, in step S3, when drilling to a depth of 1.0 to 1.5 times the borehole diameter above the top plate of the key seismic soil layer, the low-disturbance drilling mode adopts mud wall protection and controls the drilling rate to not exceed 0.2 m / min, and the hole is cleaned before core sampling until the returned mud does not contain obvious sediment.

[0022] A seismic parameter-guided system for accurate acquisition of undisturbed borehole samples, wherein the system utilizes the method described in any of the above-mentioned embodiments, including:

[0023] The exploration data acquisition and seismic key layer identification module is used to acquire geotechnical engineering investigation data of the target site, and based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one seismic key soil layer that has a controlling effect on the seismic response of the site.

[0024] The dynamic design module for borehole parameters is used to dynamically plan the drilling depth, core sampling location, and core sampling tool specifications based on the location and thickness of the key seismic soil layer identified by the key seismic soil layer identification module, so that the planned core sampling location at least covers the top plate, bottom plate, and middle area of ​​the key seismic soil layer.

[0025] The directional drilling and undisturbed sampling module is used to perform drilling operations. When the drilling depth approaches the core sampling position planned by the dynamic design module of drilling parameters, it switches to low-disturbance drilling mode and uses a core sampling tool that matches the specifications planned by the dynamic design module of drilling parameters to perform indentation or impact sampling at the planned position of the key seismic soil layer to obtain undisturbed soil and rock samples.

[0026] The sample packaging and information association module is used to seal the undisturbed soil and rock samples obtained by the directional drilling and undisturbed sampling modules on-site, generate a unique identification code, and associate and store the unique identification code with the three-dimensional coordinates of the core location, the corresponding key seismic soil layer number, and the exploration data.

[0027] As a preferred embodiment of the present invention, the exploration data acquisition and seismic key layer identification module specifically includes identifying and locating the seismic key soil layer:

[0028] Based on the preset rule library for identifying key soil layers for seismic resistance, the system automatically analyzes the standard penetration test blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit, and soil profile information in the input survey data.

[0029] The recognition rule base contains multiple layers of judgment rules, including at least:

[0030] The first layer is the liquefaction potential determination unit, which is used to identify saturated cohesionless soil layers that may experience a significant increase in pore water pressure under seismic motion, according to the liquefaction potential determination rules.

[0031] The second layer is the weak characteristic judgment unit, which is used to identify weak cohesive soil layers with low shear strength and high compressibility according to the weak characteristic judgment rules.

[0032] The third layer is the wave velocity interface determination unit, which is used to identify the wave velocity interface layer where there is a significant difference in shear wave velocity between adjacent soil layers according to the wave velocity interface determination rules.

[0033] The module outputs soil layers that satisfy any judgment unit rule as key soil layers for seismic resistance, and records their type, depth range, and core discrimination indicators.

[0034] As a preferred technical solution of the present invention, the liquefaction potential determination unit is based on a set of preset threshold data related to soil depth and site design ground motion parameters.

[0035] The liquefaction potential determination unit is specifically used to: compare the measured value of the standard penetration test blow count of the soil layer obtained from the survey with the preset threshold at the corresponding depth, and determine that the soil layer is a key seismic soil layer with liquefaction potential based on the comparison result that the measured value is less than the threshold.

[0036] As a preferred embodiment of the present invention, the specifications of the core sampling tool dynamically planned in the drilling parameter dynamic design module specifically include:

[0037] Based on the type of seismic critical soil layer output by the seismic critical layer identification module, select the type, diameter, and area ratio of the soil sampler;

[0038] Among them, for soil layers identified by the liquefaction potential determination unit or the weak characteristic determination unit, a thin-walled soil sampler with an area ratio of less than 15% is selected.

[0039] For soil layers or harder soil layers identified by the wave velocity interface determination unit, select a dual-tube soil sampler.

[0040] As a preferred technical solution of the present invention, the low-disturbance drilling mode in the directional drilling and undisturbed sampling module specifically performs the following actions: when drilling to a depth of 1.0 to 1.5 times the borehole diameter above the top plate of the key seismic soil layer planned by the borehole parameter dynamic design module, mud slurry is used for wall protection and the drilling rate is controlled to not exceed 0.2 m / min, and a hole cleaning operation is performed before core sampling until the returned mud does not contain obvious sediment.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] 1. By constructing a multi-parameter fusion rule library for identifying key seismic soil layers, the system enables automatic identification and location of liquefaction layers, weak layers, and wave velocity interface layers that control the seismic response of a site. Based on the identification results, the system dynamically plans sampling locations to ensure that the sampling range fully covers the top, bottom, and middle sections of the key layers. This avoids the omission of key features due to sampling location deviations in traditional methods. As a result, the obtained undisturbed soil samples can truly reflect the engineering characteristics of the weak points in the site's seismic resistance. This provides highly representative and targeted sample foundations for subsequent seismic response analysis, liquefaction identification, and foundation treatment design, significantly improving the accuracy and reliability of seismic safety assessment.

[0043] 2. Based on the identified key soil layer type, the appropriate soil sampler specifications are automatically matched. For soft soil layers, a low area ratio thin-walled soil sampler is used, and for hard soil layers or interface layers, a double-tube soil sampler is used. When approaching the key layer, the low-disturbance drilling mode is switched, and the drilling rate and hole cleaning standards are strictly controlled to minimize soil disturbance during the sampling process and ensure the original state of the sample.

[0044] 3. By generating a unique identifier for each sample and automatically linking and storing it with the three-dimensional coordinates of the sampling location, the key layer number, and the original survey data, the sample information is digitized, structured, and traceable throughout the entire process, providing a reliable data foundation and management support for subsequent test data analysis, seismic parameter verification, and engineering applications. Attached Figure Description

[0045] Figure 1 This is an overall flowchart of the method for accurately obtaining undisturbed samples of soil and rock boreholes guided by seismic parameters according to the present invention. Figure 2 This is a framework diagram of the overall module composition of the seismic parameter-guided system for accurately acquiring undisturbed samples from rock and soil boreholes according to the present invention. Detailed Implementation

[0046] The technical solutions 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] This invention provides a method for accurately obtaining undisturbed samples from soil and rock boreholes guided by seismic parameters, comprising the following steps:

[0049] S1. Exploration data acquisition and identification of key seismic layers: acquire geotechnical engineering investigation data of the target site, and based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one key seismic soil layer that has a controlling effect on the seismic response of the site.

[0050] S2. Dynamic design of drilling parameters: Based on the location and thickness of the identified key seismic soil layers, the drilling depth, core sampling location and core sampling tool specifications are dynamically planned so that the planned core sampling location at least covers the top slab, bottom slab and middle area of ​​the key seismic soil layers.

[0051] S3. Guided drilling and undisturbed sampling: When drilling is performed, switch to low-disturbance drilling mode when the drilling depth is close to the planned core sampling position. Use core sampling tools that match the specifications of the undisturbed soil sample to perform indentation or impact sampling at the planned position of the key seismic soil layer to obtain undisturbed soil and rock samples.

[0052] S4. Sample Packaging and Information Association: The obtained undisturbed soil and rock samples are sealed on-site and a unique identification code is generated; the unique identification code is associated and stored with the three-dimensional coordinates of the core sampling location, the corresponding key seismic soil layer number, and the exploration data.

[0053] Furthermore, the identification and location of key seismic soil layers in step S1 includes: automatically analyzing the standard penetration test blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit and soil profile information in the input survey data according to the preset key seismic soil layer identification rule library.

[0054] The recognition rule base contains multiple layers of decision rules, including at least:

[0055] The first layer is the liquefaction potential determination rule: used to identify saturated cohesive-free soil layers where pore water pressure may increase significantly under seismic action;

[0056] The second layer consists of rules for determining weak characteristics: used to identify weak cohesive soil layers with low shear strength and high compressibility;

[0057] The third layer is the wave velocity interface determination rule: used to identify wave velocity interface layers where there are significant differences in shear wave velocities between adjacent soil layers;

[0058] Output the soil layers that satisfy any of the judgment rules as the key soil layers for seismic resistance, and record their type, depth range and core discrimination index.

[0059] Furthermore, the liquefaction potential determination rule is based on a set of preset threshold values ​​that are associated with soil depth and site design ground motion parameters. The liquefaction potential determination rule includes: comparing the measured standard penetration test blow count of the soil layer obtained from the survey with the preset threshold at the corresponding depth. If the measured value is less than the threshold, the soil layer is determined to be a key seismic soil layer with liquefaction potential.

[0060] Furthermore, in step S2, the specifications of the core sampling device are dynamically planned as follows: the type, diameter, and area ratio of the soil sampler are selected according to the type of the key seismic soil layer.

[0061] For soil layers identified by the first or second layer determination rules, use thin-walled soil samplers with an area ratio of less than 15%.

[0062] For soil layers or harder soil layers identified by the third-layer determination rule, a double-tube soil sampler should be selected.

[0063] Furthermore, in step S3, when drilling to a depth of 1.0 to 1.5 times the borehole diameter above the top of the key seismic soil layer in the low-disturbance drilling mode, mud slurry is used for wall protection and the drilling rate is controlled to not exceed 0.2 m / min. Before core sampling, the borehole is cleaned until the returned mud slurry does not contain obvious sediment.

[0064] A seismic parameter-guided system for accurate acquisition of undisturbed borehole samples in soil and rock, employing any of the methods described above, including:

[0065] The exploration data acquisition and seismic key layer identification module is used to acquire geotechnical engineering investigation data of the target site, and based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one seismic key soil layer that has a controlling effect on the seismic response of the site.

[0066] The dynamic design module for borehole parameters is used to dynamically plan the drilling depth, core sampling location, and core sampling tool specifications based on the location and thickness of the key seismic soil layer identified by the key seismic soil layer identification module, so that the planned core sampling location at least covers the top plate, bottom plate, and middle area of ​​the key seismic soil layer.

[0067] The directional drilling and undisturbed sampling module is used to perform drilling operations. When the drilling depth approaches the core sampling position planned by the dynamic design module of drilling parameters, it switches to low-disturbance drilling mode and uses a core sampling tool that matches the specifications planned by the dynamic design module of drilling parameters to perform indentation or impact sampling at the planned position of the key seismic soil layer to obtain undisturbed soil and rock samples.

[0068] The sample packaging and information association module is used to seal the undisturbed soil and rock samples obtained by the directional drilling and undisturbed sampling modules on-site, generate a unique identification code, and associate and store the unique identification code with the three-dimensional coordinates of the core location, the corresponding key seismic soil layer number, and the exploration data.

[0069] Furthermore, in the exploration data acquisition and seismic key layer identification module, identifying and locating the seismic key soil layers specifically includes:

[0070] Based on the preset rule library for identifying key soil layers for seismic resistance, the system automatically analyzes the standard penetration test blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit, and soil profile information in the input survey data.

[0071] The recognition rule base contains multiple layers of decision rules, including at least:

[0072] The first layer is the liquefaction potential determination unit, which is used to identify saturated cohesionless soil layers that may experience a significant increase in pore water pressure under seismic motion, according to the liquefaction potential determination rules.

[0073] The second layer is the weak characteristic judgment unit, which is used to identify weak cohesive soil layers with low shear strength and high compressibility according to the weak characteristic judgment rules.

[0074] The third layer is the wave velocity interface determination unit, which is used to identify the wave velocity interface layer where there is a significant difference in shear wave velocity between adjacent soil layers according to the wave velocity interface determination rules.

[0075] The module outputs soil layers that satisfy any judgment unit rule as key soil layers for seismic resistance, and records their type, depth range, and core discrimination indicators.

[0076] Furthermore, the liquefaction potential determination unit is based on a set of preset threshold values ​​that are associated with soil depth and site design ground motion parameters.

[0077] The liquefaction potential determination unit is specifically used to: compare the measured value of the standard penetration test blow count of the soil layer obtained from the survey with the preset threshold at the corresponding depth, and determine the soil layer as a key seismic soil layer with liquefaction potential based on the comparison result that the measured value is less than the threshold.

[0078] Furthermore, in the dynamic design module for drilling parameters, the specifications of the dynamically planned coring tool specifically include:

[0079] Based on the type of seismic critical soil layer output by the seismic critical layer identification module, select the type, diameter, and area ratio of the soil sampler;

[0080] Among them, for soil layers identified by the liquefaction potential determination unit or the weak characteristic determination unit, a thin-walled soil sampler with an area ratio of less than 15% is selected.

[0081] For soil layers or harder soil layers identified by the wave velocity interface determination unit, select a dual-tube soil sampler.

[0082] Furthermore, in the low-disturbance drilling mode of the directional drilling and undisturbed sampling module, the following actions are specifically performed: when drilling to a depth of 1.0 to 1.5 times the borehole diameter above the top plate of the key seismic soil layer planned by the borehole parameter dynamic design module, mud slurry is used for wall protection and the drilling rate is controlled to not exceed 0.2 m / min. Before core sampling, a hole cleaning operation is performed until the returned mud does not contain obvious sediment.

[0083] Example 2

[0084] This embodiment takes a coastal soft soil area as an example to illustrate the specific implementation process of the method for accurately obtaining undisturbed samples of rock and soil boreholes guided by seismic parameters. The seismic fortification intensity of the area is 8 degrees, the peak ground acceleration of the basic ground motion is 0.20g, and the soil layers of the site mainly include fill, silt, silty clay and silty clay.

[0085] First, step S1 is executed to obtain geotechnical engineering investigation data for the site, including standard penetration test (SPT) blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit, and soil profile information. This data is then input into a preset seismic key soil layer identification rule library for automatic analysis. The liquefaction potential judgment rule in the rule library is based on preset threshold data related to depth and seismic motion parameters. For example, at a depth of 10 meters, the corresponding liquefaction discrimination threshold is 15 blows. The measured SPT blow count for the silty sand layer at this depth is 12 blows, less than the threshold of 15 blows. Therefore, the silty sand layer is determined to be a seismic key soil layer with liquefaction potential. The second layer, the weak characteristic judgment rule, identifies the silty clay layer as a weak cohesive soil seismic key layer based on indicators such as natural water content greater than the liquid limit and compression modulus less than 4 MPa. The third layer, the wave velocity interface judgment rule, identifies a wave velocity interface layer where the shear wave velocity difference between the silty sand layer and the underlying silty clay layer is greater than 150 m / s. Finally, the three types of seismic key soil layers, their depth ranges, and core discrimination indicators are output.

[0086] In step S2, based on the identified location and thickness of the key seismic soil layers, the drilling depth is dynamically planned to be 25 meters. The core sampling location covers the top, bottom and middle of the silty sand layer, the top and bottom of the silty clay layer, and a range of 1 meter above and below the wave velocity interface layer. For the silty sand layer and the silty clay layer, a thin-walled soil sampler with an area ratio of 10% is selected; for the wave velocity interface layer and the harder silty clay layer below it, a double-tube soil sampler is selected.

[0087] In step S3, an XY-100 drilling rig is used for drilling operations. When the drilling reaches a depth of 1.2 times the borehole diameter above the top plate of the silty sand layer, the drilling mode is switched to low-disturbance drilling mode. Sodium-based bentonite mud is used for wall protection, and the drilling rate is controlled to be ≤0.18 meters per minute. The borehole is cleaned by circulation until there is no obvious sediment in the returned mud. Then, the corresponding soil sampler is used at the planned location to perform forced sampling to obtain undisturbed soil samples.

[0088] In step S4, the soil sample is immediately placed into a galvanized thin-walled liner on site, sealed with wax at both ends, and a QR code label is attached as a unique identifier. The QR code, along with the three-dimensional coordinates of the core sampling point, the number of the seismic key layer, and the corresponding survey data, are uploaded to the cloud database for associated storage via a mobile terminal.

[0089] Example 3

[0090] This embodiment takes a river valley terrace site as an example to illustrate the modular implementation of the system. The main soil layers of the site are alternating layers of sand and gravel and silt, and the seismic fortification intensity is 7 degrees.

[0091] After the system starts, the exploration data acquisition and seismic key layer identification module reads the exploration data, calls the rule base for analysis, the liquefaction potential determination unit determines the saturated silt layer at a depth of 12 meters as the liquefaction key layer based on the liquefaction critical value of 13 blows, the weak characteristics determination unit identifies the shallow fill layer as the weak key layer, and the wave velocity interface determination unit identifies the interface between sand and gravel and silt as the wave velocity key layer. The module outputs the key layer information to the borehole parameter dynamic design module.

[0092] The dynamic design module for drilling parameters plans a drilling depth of 20 meters based on the depth and type of the key layer. Core samples are taken from the middle of the silt layer, the top and bottom plates, and above and below the interface. Thin-walled soil samplers with an area ratio of 12% are selected for the silt and fill layers, and double-tube soil samplers are selected for the sand and gravel layers. The planned parameters are transmitted to the directional drilling and undisturbed sampling module.

[0093] The directional drilling and undisturbed sampling module controls the DPP-100 drilling rig to perform drilling. At a depth of 1.0 times the borehole diameter above the top plate of the key layer, it switches to a low-disturbance mode, uses polymer mud for wall protection, and controls the drilling rate at 0.15 meters per minute. After cleaning the borehole, it uses the static pressure method for sampling. The sample packaging and information association module uses an intelligent packaging platform to automatically seal the sample, generate RFID tags to associate coordinates and soil layer data, and store them in the local server.

[0094] Compare with Example 1

[0095] This comparative example uses the traditional uniformly distributed coring method in the same coastal site. The drilling depth is 25 meters, and coring is carried out at equal intervals of 2 meters. The key seismic layers were not identified and sampled in a focused manner. Standard thick-walled soil samplers were used uniformly for coring. The drilling process did not adopt a low-disturbance mode. Mud was used for wall protection, but the drilling rate and hole cleaning standards were not strictly controlled. After sampling, the samples were only labeled with the hole number and depth, and no information association was established.

[0096] Compare with Example 2

[0097] This comparative example uses manual experience to determine key layers and take samples. Engineers make empirical judgments about liquefiable and weak layers based on the survey report, but do not use a rule-based system for analysis. Core sampling locations are determined based on experience and do not dynamically cover the top and bottom plates of key layers. Soil samplers are selected based on rough judgment of soil properties and are not strictly matched according to area ratio. Conventional processes are used in the drilling process and low-disturbance control is not implemented. Information is recorded manually after sample packaging and no unique identifier is used to associate with data.

[0098] Experimental data and explanation

[0099] To verify the advantages of the method of the present invention compared with the control example, samples were taken from the same borehole location in a coastal soft soil area using Example 2 of the present invention, Control Example 1, and Control Example 2, respectively. Indoor geotechnical tests were conducted on the obtained undisturbed samples. The main test indicators included natural density, water content, void ratio, compression modulus, shear wave velocity, and dynamic triaxial liquefaction stress ratio. The test results are summarized in the table below:

[0100] Table 1 Comparison of Geotechnical Test Results of Uncirculated Samples

[0101]

[0102] As can be seen from the table above:

[0103] 1. Sample quality comparison: The natural density, moisture content, and void ratio of the undisturbed sample taken in Example 2 are closest to the field survey data, indicating that the disturbance is minimal. In contrast, the sample representativeness of Control Example 1 is insufficient due to the use of equidistant core sampling and a general soil sampler. In particular, the moisture content and void ratio of the silty sand layer and the silty clay layer deviate significantly from the true values, indicating that drainage and structural damage occurred during the sampling process. Although Control Example 2 was identified as a key layer based on experience, the sample quality is still lower than that of Example 2 because the core sampling process was not systematically optimized.

[0104] 2. Reliability of mechanical and wave parameters: In Example 2, the shear wave velocity of the silt layer was 185 m / s, which is highly consistent with the field wave velocity test result of 180 m / s. The liquefaction stress ratio obtained from the dynamic triaxial test was 0.18, which truly reflects the liquefaction potential of the layer under seismic motion. In Control Example 1, due to sample disturbance, the shear wave velocity was lower and the liquefaction stress ratio was higher, which may have underestimated the liquefaction risk. The compression modulus of the silty clay layer in Example 2 was 2.8 MPa, which is consistent with the characteristics of soft soil, while that in Control Example 1 was only 2.2 MPa, which may have been overestimated due to disturbance. The shear wave velocity of the wave velocity interface layer in Example 2 was 320 m / s, which was significantly higher than that in the Control Example, indicating that the double-tube soil sampler effectively protected the hard soil structure.

[0105] 3. Completeness of the characterization of key seismic layers: Example 2 automatically identified and fully covered the core samples through the rule base, and obtained a complete original sample sequence of the liquefied layer, weak layer and wave velocity interface, which provided accurate input for the site seismic response analysis. In contrast, the uniformly distributed core samples in Example 1 failed to capture the key layers, resulting in the absence of samples in the middle of the silt layer. Although the key layers were obtained in Example 2, the top and bottom plates were not covered, and the interface features were incomplete.

[0106] 4. Information traceability: Example 2 uses a unique identifier to link the sample with the survey data throughout the entire process, ensuring the consistency between the test data and the site conditions. This is beneficial for the subsequent verification and updating of seismic parameters. In contrast, Comparative Example 1 and Comparative Example 2 rely on manual recording, which poses a risk of information errors and omissions and difficulties in traceability.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for accurately obtaining undisturbed samples from soil and rock boreholes guided by seismic parameters, characterized in that, Includes the following steps: S1. Exploration data acquisition and identification of key seismic layers: acquire geotechnical engineering investigation data of the target site, and based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one key seismic soil layer that has a controlling effect on the seismic response of the site. S2. Dynamic design of drilling parameters: Based on the location and thickness of the identified key seismic soil layers, the drilling depth, core sampling location and core sampling tool specifications are dynamically planned so that the planned core sampling location at least covers the top slab, bottom slab and middle area of ​​the key seismic soil layers. S3. Guided drilling and undisturbed sampling: When drilling is performed, switch to low-disturbance drilling mode when the drilling depth is close to the planned core sampling position. Use core sampling tools that match the specifications of the undisturbed soil sample to perform indentation or impact sampling at the planned position of the key seismic soil layer to obtain undisturbed soil and rock samples. S4. Sample Packaging and Information Association: The obtained undisturbed soil and rock samples are sealed on-site and a unique identification code is generated; the unique identification code is associated and stored with the three-dimensional coordinates of the core sampling location, the corresponding key seismic soil layer number, and the exploration data.

2. The method for accurately obtaining undisturbed samples from soil and rock boreholes guided by seismic parameters according to claim 1, characterized in that, The step S1 of identifying and locating key seismic soil layers includes: automatically analyzing the standard penetration test blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit and soil profile information in the input exploration data according to the preset key seismic soil layer identification rule library. The recognition rule base contains multiple layers of judgment rules, including at least: The first layer is the liquefaction potential determination rule: used to identify saturated cohesive-free soil layers where pore water pressure may increase significantly under seismic action; The second layer consists of rules for determining weak characteristics: used to identify weak cohesive soil layers with low shear strength and high compressibility; The third layer is the wave velocity interface determination rule: used to identify wave velocity interface layers where there are significant differences in shear wave velocities between adjacent soil layers; Output the soil layers that satisfy any of the judgment rules as the key soil layers for seismic resistance, and record their type, depth range and core discrimination index.

3. The method for accurately obtaining undisturbed samples from soil and rock boreholes guided by seismic parameters according to claim 2, characterized in that, The liquefaction potential determination rule is based on a set of preset threshold values ​​that are associated with soil depth and site design ground motion parameters. The liquefaction potential determination rule includes: comparing the measured value of the standard penetration test blow count of the soil layer obtained from the survey with a preset threshold at the corresponding depth; if the measured value is less than the threshold, the soil layer is determined to be a key seismic soil layer with liquefaction potential.

4. The method for accurately obtaining undisturbed samples of soil and rock boreholes guided by seismic parameters according to claim 2, characterized in that, In step S2, the specifications of the core sampling tool are dynamically planned as follows: the type, diameter, and area ratio of the soil sampler are selected according to the type of the key seismic soil layer. For soil layers identified by the first or second layer determination rules, use thin-walled soil samplers with an area ratio of less than 15%. For soil layers or harder soil layers identified by the third-layer determination rule, a double-tube soil sampler should be selected.

5. The method for accurately obtaining undisturbed samples of soil and rock boreholes guided by seismic parameters according to claim 1, characterized in that, In step S3, the low-disturbance drilling mode uses mud slurry to protect the borehole wall and controls the drilling rate to not exceed 0.2 m / min when drilling to a depth of 1.0 to 1.5 times the borehole diameter above the top plate of the key seismic soil layer. Before core sampling, the borehole is cleaned until the returned mud does not contain obvious sediment.

6. A seismic parameter-guided system for accurately acquiring undisturbed samples from soil and rock boreholes, characterized in that, The system application of the method as described in any one of claims 1 to 5 includes: The exploration data acquisition and seismic key layer identification module is used to acquire geotechnical engineering investigation data of the target site, and based on the soil physical and mechanical parameters in the geotechnical engineering investigation data, identify and locate at least one seismic key soil layer that has a controlling effect on the seismic response of the site. The dynamic design module for borehole parameters is used to dynamically plan the drilling depth, core sampling location, and core sampling tool specifications based on the location and thickness of the key seismic soil layer identified by the key seismic soil layer identification module, so that the planned core sampling location at least covers the top plate, bottom plate, and middle area of ​​the key seismic soil layer. The directional drilling and undisturbed sampling module is used to perform drilling operations. When the drilling depth approaches the core sampling position planned by the dynamic design module of drilling parameters, it switches to low-disturbance drilling mode and uses a core sampling tool that matches the specifications planned by the dynamic design module of drilling parameters to perform indentation or impact sampling at the planned position of the key seismic soil layer to obtain undisturbed soil and rock samples. The sample packaging and information association module is used to seal the undisturbed soil and rock samples obtained by the directional drilling and undisturbed sampling modules on-site, generate a unique identification code, and associate and store the unique identification code with the three-dimensional coordinates of the core location, the corresponding key seismic soil layer number, and the exploration data.

7. The seismic parameter-guided system for accurately acquiring undisturbed samples from soil and rock boreholes according to claim 6, characterized in that, The exploration data acquisition and seismic key layer identification module specifically includes identifying and locating the seismic key soil layer, which includes: Based on the preset rule library for identifying key soil layers for seismic resistance, the system automatically analyzes the standard penetration test blow count, shear wave velocity, cone tip resistance, natural water content, liquid limit, and soil profile information in the input survey data. The recognition rule base contains multiple layers of judgment rules, including at least: The first layer is the liquefaction potential determination unit, which is used to identify saturated cohesionless soil layers that may experience a significant increase in pore water pressure under seismic motion, according to the liquefaction potential determination rules. The second layer is the weak characteristic judgment unit, which is used to identify weak cohesive soil layers with low shear strength and high compressibility according to the weak characteristic judgment rules. The third layer is the wave velocity interface determination unit, which is used to identify the wave velocity interface layer where there is a significant difference in shear wave velocity between adjacent soil layers according to the wave velocity interface determination rules. The module outputs soil layers that satisfy any judgment unit rule as key soil layers for seismic resistance, and records their type, depth range, and core discrimination indicators.

8. The seismic parameter-guided system for accurately acquiring undisturbed samples from soil and rock boreholes according to claim 7, characterized in that, The liquefaction potential determination unit is based on a set of preset threshold values ​​that are associated with soil depth and site design ground motion parameters. The liquefaction potential determination unit is specifically used to: compare the measured value of the standard penetration test blow count of the soil layer obtained from the survey with the preset threshold at the corresponding depth, and determine that the soil layer is a key seismic soil layer with liquefaction potential based on the comparison result that the measured value is less than the threshold.

9. The seismic parameter-guided system for accurately acquiring undisturbed samples from soil and rock boreholes according to claim 7, characterized in that, In the dynamic design module for drilling parameters, the specifications of the dynamically planned coring tool specifically include: Based on the type of seismic critical soil layer output by the seismic critical layer identification module, select the type, diameter, and area ratio of the soil sampler; Among them, for soil layers identified by the liquefaction potential determination unit or the weak characteristic determination unit, a thin-walled soil sampler with an area ratio of less than 15% is selected. For soil layers or harder soil layers identified by the wave velocity interface determination unit, select a dual-tube soil sampler.

10. The seismic parameter-guided system for accurately acquiring undisturbed samples from soil and rock boreholes according to claim 6, characterized in that, The low-disturbance drilling mode in the directional drilling and undisturbed sampling module specifically performs the following actions: when drilling to a depth of 1.0 to 1.5 times the borehole diameter above the top plate of the key seismic soil layer planned by the borehole parameter dynamic design module, mud slurry is used for wall protection and the drilling rate is controlled to not exceed 0.2 m / min. Before core sampling, a hole cleaning operation is performed until the returned mud does not contain obvious sediment.

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