Method and device for evaluating rapid compactness of hydraulic fill coral sand and storage medium

Abstract

The application relates to the technical field of in-situ testing of geotechnical engineering, in particular to a method and device for rapidly evaluating the compactness of hydraulic fill coral sand and a storage medium, wherein the method comprises the following steps: arranging measuring points to collect in-situ penetration resistance, static cone penetration resistance, shear wave velocity and soil density; sampling to determine particle size distribution and determine a crushing rate parameter; correcting the in-situ penetration resistance by using the crushing rate parameter to eliminate the influence of particle crushing; fusing the corrected penetration resistance with the other three types of parameters to obtain a comprehensive compactness fusion index; comparing the comprehensive compactness fusion index with a target threshold value, dividing the compactness level and determining whether the design requirements are met, marking the qualified and unqualified areas; carrying out spatial interpolation based on the fusion indexes of all measuring points to generate a compactness distribution map and highlight the unqualified areas; and the application realizes rapid and accurate evaluation of the compactness of the hydraulic fill coral sand foundation and visual positioning of the unqualified areas through the collaborative fusion of multiple parameters.

Description

Technical Field

[0001] This application relates to the field of in-situ testing technology in geotechnical engineering, and in particular to a method, apparatus and storage medium for rapid compaction evaluation of dredged coral sand. Background Technology

[0002] Reclaimed coral sand is a primary source of fill material for island and reef engineering projects and coastal reclamation projects. After being hydraulically transported from the seabed to the target area, the fill material is typically in an initial loose state with a high porosity and low density. It requires foundation treatment such as vibro-compaction, dynamic compaction, or surcharge preloading before it can be used as the foundation for buildings and structures. Therefore, after the foundation treatment is completed, a rapid and accurate evaluation of the density of the reclaimed coral sand fill material is a crucial step in ensuring that the project quality meets design requirements.

[0003] Existing technologies for evaluating the compaction of sandy soil foundations mainly include the Standard Penetration Test (SPT), the Cone Penetration Test (CPT), in-situ density tests (such as the sand cone method and the nuclear density meter method), and wave velocity evaluation methods based on shear wave velocity. These methods have formed relatively mature evaluation systems for conventional sandy soils such as quartz sand, but they all face significant technical shortcomings when applied to the special soil and rock material of dredged coral sand.

[0004] First, the standard penetration test (SPT) has limitations in its applicability to coral sand. Coral sand particles are composed of biogenic calcium carbonate skeletal debris, exhibiting irregular shapes, well-developed internal porosity, and low individual particle strength. During the hammer penetration process in the SPT, the hammering energy causes violent collisions and breakage of coral sand particles around the periphery and bottom of the penetrator, resulting in a significantly higher and more volatile measured in-situ penetration resistance parameter, N. Because the degree of particle breakage is spatially uneven, the empirical correlation between N and relative density (Dr) fails in coral sand. Using the existing N-Dr relationship for quartz sand to evaluate coral sand density will lead to systematic misjudgments.

[0005] Second, the applicability of the static cone penetration test in coral sand is limited. The static cone penetration test measures the tip resistance by continuously penetrating a cone. Established in quartz sand Empirical relationships with parameters such as Dr and internal friction angle. However, coral sand also undergoes particle breakage during cone penetration, and the development of the breakage zone alters the stress field and shear failure mode near the cone, leading to changes in the coral sand's... -Dr relationship is significantly different from that of quartz sand. Directly applying the formula for quartz sand... -Dr's experience suggests that the actual density of coral sand may be overestimated or underestimated.

[0006] Third, the efficiency limitations of in-situ density testing in coral sand. The sand-filling method and nuclear density meter method are direct means of determining in-situ density, providing intuitive and reliable evaluation results. However, the sand-filling method involves cumbersome procedures and can take up to 30 minutes per point. min ~60 min Nuclear density meters require radiation safety management and multi-point calibration. For coral sand reclamation projects, the evaluation area typically reaches tens of thousands or even hundreds of thousands of square meters. Using the above method for large-area, densely distributed testing would consume a lot of manpower, resources, and time, and could not meet the needs of rapid evaluation at the project site.

[0007] Fourth, there is a lack of evaluation standards for coral sand compaction based on in-situ wave velocity. Multichannel analysis of surface waves (MASW) can rapidly determine the shear wave velocity of soil. This allows for the evaluation of density and mechanical properties. However, existing empirical relationships between shear wave velocity and density are mainly established for quartz sand, cohesive soil, and rock. Due to its unique particle structure and variable degree of cementation, coral sand exhibits a fundamentally different wave velocity-density-stress relationship compared to conventional soils. Currently, no relationship has been established applicable to dredged coral sand. The Dr evaluation criteria limit the application of the surface wave method in coral sand engineering.

[0008] In summary, existing methods for evaluating the density of dredged coral sand have technical problems such as in-situ penetration resistance parameters being affected by particle breakage, the inapplicability of empirical relationships in static cone penetration tests, low efficiency of field density tests, and a lack of wave velocity evaluation standards. These methods cannot meet the actual needs of island and reef engineering for rapid, accurate, and large-area evaluation of foundation treatment effects. Summary of the Invention

[0009] To address this, the present invention provides a method, apparatus, and storage medium for rapid evaluation of the density of blown coral sand, thereby overcoming the problems in the prior art where the evaluation of the density of blown coral sand is affected by particle breakage, has large deviations in single indicators, and has low testing efficiency, making it impossible to achieve rapid, accurate, and large-area evaluation.

[0010] To achieve the above objectives, this invention provides a method for rapid density evaluation of dredged coral sand. It includes:

[0011] Step S1: Set up measuring points in the evaluation area and collect in-situ test parameters at each measuring point. The in-situ test parameters include in-situ penetration resistance parameters, static cone penetration resistance parameters and shear wave velocity parameters obtained by standard penetration test, and soil density parameters obtained by nuclear density meter.

[0012] Step S2: Take a sample of soil at the measuring point, determine the particle size distribution of the soil, and determine the particle breakage rate parameter of the soil based on the particle size distribution.

[0013] Step S3: Use the particle breakage rate parameter to correct the in-situ penetration resistance parameter to obtain the equivalent original penetration resistance parameter that eliminates the influence of particle breakage.

[0014] Step S4: The equivalent original penetration resistance parameter is fused with the static penetration resistance parameter, shear wave velocity parameter and soil density parameter to obtain the comprehensive compaction fusion index of each measuring point.

[0015] Step S5: Compare the comprehensive density fusion index with the preset target density threshold, divide the density level of each measuring point according to the comparison result, and determine whether each measuring point meets the design requirements. Based on the determination results of each measuring point, mark the qualified area that meets the design requirements and the unqualified area that does not meet the design requirements in the evaluation area.

[0016] Step S6: Based on the comprehensive density fusion index of all measuring points, a spatial interpolation method is used to generate a density spatial distribution map covering the evaluation area, and the substandard areas are highlighted in the density spatial distribution map.

[0017] Furthermore, in step S1, the measurement points of the standard penetration test are arranged in a grid pattern, and the test points of the nucleus-free density meter coincide with the measurement points of the standard penetration test, thereby realizing the synchronous acquisition of in-situ test data.

[0018] Further, in step S2, the formula for calculating the particle breakage rate parameter is:

[0019] ;

[0020] Wherein, Br is the particle breakage rate parameter, Bt is the breakage potential after the particle breakage test, and Bp is the breakage potential before the particle breakage test; the breakage potential Bp before the particle breakage test is the area enclosed by the soil particle size distribution curve and the particle size coordinate axis before the particle breakage test, and the breakage potential Bt after the particle breakage test is the area enclosed by the soil particle size distribution curve and the particle size coordinate axis after the particle breakage test. The breakage potential is obtained by integrating the content of particles with a particle size less than 0.074 mm and the particle size distribution data of each distribution interval.

[0021] Further, in step S3, the formula for calculating the corrected in-situ penetration resistance parameter is as follows:

[0022] ;

[0023] in, Br is the measured penetration blow count obtained at the measuring point through a standard penetration test, and Br is the particle breakage rate parameter. The coefficient representing the impact of particle breakage is . The value range is 0.2 to 0.5.

[0024] Furthermore, the particle breakage influence coefficient The determination is based on a comprehensive analysis of the calcium carbonate content of the dredged coral sand, the strength of the parent rock, and the initial porosity; when the calcium carbonate content is greater than 90%, the parent rock strength is less than 20 MPa, and the initial porosity is greater than 1.4, Take 0.4~0.5; when the calcium carbonate content is 70%~90%, the parent rock strength is 20MPa~40MPa, and the initial void ratio is 1.2~1.4, Take a value of 0.2~0.3; when the calcium carbonate content is less than 70%, the parent rock strength is greater than 40 MPa, and the initial void ratio is less than 1.2, Take 0.2.

[0025] Further, in step S4, the formula for calculating the comprehensive density fusion index is:

[0026] ;

[0027] Wherein, DI is the comprehensive density fusion index. These are the corrected in-situ penetration resistance parameters. For cone tip resistance, The shear wave velocity, Wet density, To preset in-situ penetration resistance parameters, To preset the cone tip resistance, For preset shear wave velocity, To preset the wet density, , , and Used to convert parameters into dimensionless relative values; , , , These are the weighting coefficients, and the sum of all weighting coefficients is 1; weighting coefficients The value range is 0.25~0.40. The value range is 0.20~0.35. The value range is 0.20~0.35. The value range is 0.10 to 0.20.

[0028] Furthermore, the weighting coefficients are determined using principal component analysis or backpropagation neural network training based on static load test data from the calibration area or sampled indoor test data.

[0029] Further, in step S5, determining whether each measuring point meets the design requirements includes:

[0030] When the comprehensive density fusion index is greater than or equal to the sum of the target density value and the allowable deviation value, the density is determined to meet the design requirements;

[0031] When the comprehensive density fusion index is between the difference between the target density value and the allowable deviation value and the sum of the target density value and the allowable deviation value, the density is determined to meet the design requirements, and local reinforcement treatment is required.

[0032] When the comprehensive compactness fusion index is less than or equal to the difference between the target compactness value and the allowable deviation value, it is determined that the compactness does not meet the design requirements and the foundation treatment needs to be carried out again.

[0033] The allowable deviation value is 0.05 to 0.10 times the target density value. The bearing capacity requirements and deformation control standards for the dredged coral sand foundation in the engineering design documents are comprehensively determined based on the measured DI values ​​of the measuring points in the calibration area that meet the design requirements.

[0034] Compared with the prior art, the beneficial effects of the present invention are that, in this embodiment, a portable particle size analyzer is used to quickly determine the particle size distribution and calculate the Hardin relative breakage rate on site, thereby achieving in-situ rapid quantification of particle breakage rate. The sampling location corresponds to the measuring point and the sampling mass is preferably 80g~120g to ensure representativeness and testing accuracy. This provides a quantitative basis for subsequent correction of in-situ penetration resistance parameters and effectively solves the problem of in-situ test parameter distortion caused by particle breakage in dredged coral sand.

[0035] Furthermore, this embodiment introduces a particle breakage influence coefficient. Furthermore, a graded and quantitative correspondence was established between the standard penetration test and calcium carbonate content, parent rock strength, and initial void ratio, enabling differentiated correction of in-situ penetration resistance parameters. This allows for the precise removal of the artificially inflated component in the measured blow count based on the fragmentation sensitivity of coral sand in different sections, ensuring that the corrected penetration blow count truly reflects the original compaction state of the soil before it is broken. This effectively eliminates the systematic interference of particle fragmentation effect on penetration resistance testing, significantly improving the applicability and evaluation accuracy of the standard penetration test in dredged coral sand.

[0036] Furthermore, this embodiment establishes a multi-parameter weighted fusion model to synergistically fuse the four indicators—corrected in-situ penetration resistance, cone tip resistance, shear wave velocity, and wet density—and uses static load test data from the calibration area or indoor test data to determine the weight coefficients using principal component analysis or backpropagation neural network training. This allows the fusion index to comprehensively reflect multi-dimensional information such as penetration resistance, wave velocity, and density, avoiding the one-sidedness and limitations of single-indicator evaluation and effectively improving the comprehensiveness and accuracy of the compaction evaluation of dredged coral sand.

[0037] Furthermore, this embodiment establishes a three-level compaction judgment standard of meeting the standard, basically meeting the standard, and not meeting the standard. The target compaction value is determined based on the measured DI value of the compliant control test point in the calibration area, and the allowable deviation value is determined based on the standard deviation and confidence coefficient of the DI value of the test point in the calibration area. This makes the judgment threshold based on measured data and statistical basis, avoids the arbitrariness of empirical values, and realizes the accurate graded evaluation of the treatment effect of dredged coral sand foundation.

[0038] Secondly, embodiments of this application provide a rapid density evaluation device for dredged coral sand, comprising:

[0039] The multi-parameter acquisition module is used to acquire in-situ penetration resistance parameters, static cone penetration resistance parameters, shear wave velocity parameters, and soil density parameters at each measuring point.

[0040] The breakage rate determination module is used to perform particle size distribution analysis on soil samples taken from the test points and calculate particle breakage rate parameters.

[0041] The data correction module is used to correct the in-situ penetration resistance parameter according to the particle breakage rate parameter to obtain an equivalent original penetration resistance parameter that eliminates the influence of particle breakage.

[0042] The data fusion module is used to weight and fuse the equivalent original penetration resistance parameter with the static penetration resistance parameter, shear wave velocity parameter and soil density parameter to calculate the comprehensive compaction fusion index of each measuring point.

[0043] The grading module is used to compare the comprehensive density fusion index with the preset target density threshold, divide the density level of each measuring point and determine whether each measuring point meets the design requirements, and mark the qualified area and the unqualified area in the evaluation area according to the judgment result.

[0044] The spatial distribution output module is used to generate a spatial distribution map of density covering the evaluation area based on the comprehensive density fusion index of all measuring points using a spatial interpolation method, and to highlight the substandard areas in the spatial distribution map of density.

[0045] Thirdly, embodiments of this application provide a computer-readable storage medium, characterized in that it stores a computer program thereon, which, when executed in a computer, causes the computer to execute the method provided in embodiments of this application. Attached Figure Description

[0046] Figure 1 This is a flowchart of the rapid compaction evaluation method for dredged coral sand according to an embodiment of this application;

[0047] Figure 2 This is a schematic diagram of the rapid compaction evaluation device for dredged coral sand according to an embodiment of this application. Detailed Implementation

[0048] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0049] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0050] like Figure 1 As shown, Figure 1 This is a flowchart of the rapid compaction evaluation method for dredged coral sand according to an embodiment of this application.

[0051] The technical solution provided in this application includes the following steps:

[0052] Step S1: Set up measuring points in the evaluation area and collect in-situ test parameters at each measuring point. The in-situ test parameters include in-situ penetration resistance parameters, static cone penetration resistance parameters and shear wave velocity parameters obtained by standard penetration test, and soil density parameters obtained by nuclear density meter.

[0053] Step S2: Take a sample of soil at the measuring point, determine the particle size distribution of the soil, and determine the particle breakage rate parameter of the soil based on the particle size distribution.

[0054] Step S3: Use the particle breakage rate parameter to correct the in-situ penetration resistance parameter to obtain the equivalent original penetration resistance parameter that eliminates the influence of particle breakage.

[0055] Step S4: The equivalent original penetration resistance parameter is fused with the static penetration resistance parameter, shear wave velocity parameter and soil density parameter to obtain the comprehensive compaction fusion index of each measuring point.

[0056] Step S5: Compare the comprehensive density fusion index with the preset target density threshold, divide the density level of each measuring point according to the comparison result, and determine whether each measuring point meets the design requirements. Based on the determination results of each measuring point, mark the qualified area that meets the design requirements and the unqualified area that does not meet the design requirements in the evaluation area.

[0057] Step S6: Based on the comprehensive density fusion index of all measuring points, a spatial interpolation method is used to generate a density spatial distribution map covering the evaluation area, and the substandard areas are highlighted in the density spatial distribution map.

[0058] Specifically, in step S1, the measurement points of the standard penetration test are arranged in a grid pattern, and the test points of the nucleus-free density meter coincide with the measurement points of the standard penetration test, so as to realize the synchronous acquisition of in-situ test data.

[0059] In this embodiment, measuring points are first arranged in a grid pattern according to the planar shape and area of ​​the evaluation region. The spacing between measuring points is determined based on the area of ​​the evaluation region and design requirements, preferably 10m to 20m. A larger spacing is used when the evaluation region area is greater than 10,000m², and a smaller spacing is used when the evaluation region area is less than or equal to 10,000m². At each measuring point, the following four in-situ tests are performed sequentially:

[0060] For the acquisition of in-situ penetration resistance parameters, the standard penetration test (SPT) was used. A 63.5 kg hammer with a free fall distance of 76 cm was used to vertically drive the standard penetrator into the soil. The number of hammer blows required for every 10 cm of penetration was recorded, and the total number of blows for a continuous 30 cm penetration was taken as the measured in-situ penetration resistance parameter for that point. The test depth of the SPT was matched to the depth of influence of the foundation treatment, preferably 1 m to 2 m below the foundation treatment depth, to ensure that the evaluation range covered the entire reinforced layer.

[0061] For the acquisition of static cone penetration resistance parameters, a static cone penetration test is used. A standard cone with a cone tip cross-sectional area of ​​10 cm² and a cone angle of 60° is uniformly pressed into the soil at a constant rate of 1 cm / s to 2 cm / s. The end resistance of the cone tip is continuously measured during the penetration process, and the arithmetic mean of the cone tip resistance within the test depth range is taken as the cone tip resistance value at that measuring point. The test lines of the static cone penetration test are laid out along the grid direction of the standard penetration test, and the test lines pass through the measuring points of the standard penetration test, so that the two types of penetration resistance data can be spatially correlated.

[0062] For the acquisition of shear wave velocity parameters, a multichannel surface wave analysis method was adopted. Multiple low-frequency geophones were arranged at equal intervals along the survey line, with the preferred geophone spacing being 1m~2m and the preferred offset distance being 5m~15m. Surface wave signals were excited using an artificial seismic source, and surface wave data were simultaneously received by the multiple geophones, recording the surface wave time history curves. Dispersion analysis was performed on the acquired time history curves to extract the surface wave dispersion curves. The dispersion curves were then converted into the shear wave velocity distribution along the depth using an inversion algorithm. The arithmetic mean or weighted average of the shear wave velocities within the depth affected by the foundation treatment was taken as the shear wave velocity value at that measuring point. The survey line for multichannel surface wave analysis coincided with the survey line for static penetration testing, and the center point of the geophone arrangement was consistent with the measuring point position of the standard penetration test, ensuring a strict spatial correspondence between the shear wave velocity data and the penetration resistance data.

[0063] For soil density parameter acquisition, a nucleus-free densitometer was used. At each measuring point, the probe of the nucleus-free densitometer was placed against the soil surface, and the instrument was activated to collect electromagnetic wave reflection signals. The dielectric constant within the probe depth range was determined using the instrument's built-in electromagnetic wave time-domain reflectometry (ETD). The wet density of the soil was then calculated based on the calibration relationship between the dielectric constant and soil density. The test points of the nucleus-free densitometer completely coincided with the standard penetration test (SPT) points. Before testing, the ground surface at the test points was leveled, and loose soil and debris were removed to ensure close contact between the probe and the soil surface. This synchronous acquisition method of multiple parameters at the same location eliminated soil heterogeneity errors introduced by spatial location offsets, providing a spatially consistent basic dataset for subsequent multi-parameter fusion.

[0064] Specifically, in step S2, the formula for calculating the particle breakage rate parameter is:

[0065] ;

[0066] Wherein, Br is the particle breakage rate parameter, Bt is the breakage potential after the particle breakage test, and Bp is the breakage potential before the particle breakage test; the breakage potential Bp before the particle breakage test is the area enclosed by the soil particle size distribution curve and the particle size coordinate axis before the particle breakage test, and the breakage potential Bt after the particle breakage test is the area enclosed by the soil particle size distribution curve and the particle size coordinate axis after the particle breakage test. The breakage potential is obtained by integrating the content of particles with a particle size less than 0.074 mm and the particle size distribution data of each distribution interval.

[0067] In this embodiment, the crushing potential is obtained by integrating the area enclosed by the particle size distribution curve and the coordinate axis with a particle size of 0.074 mm (i.e., 200-mesh sieve size). Specifically, after determining the particle size distribution curve of the soil sample using a portable particle size analyzer, the content of fine particles with a particle size smaller than 0.074 mm is accumulated. Combined with the particle size distribution data of each particle size distribution interval, the enclosed area between the particle size distribution curve and the particle size axis before and after the particle crushing test is calculated, and the initial crushing potential Bp before the particle crushing test and the residual crushing potential Bt after the particle crushing test are obtained respectively. The sampling location corresponds to each measuring point in step S1, and the sand sample mass taken at each measuring point is preferably 80g~120g to ensure the representativeness and testing accuracy of the particle size analysis. The particle crushing rate parameter Br obtained by the above method quantitatively characterizes the degree of particle breakage of the dredged coral sand under the action of penetration load, providing a quantitative basis for subsequent correction of the in-situ penetration resistance parameter.

[0068] This embodiment achieves rapid in-situ quantification of particle breakage rate by using a portable particle size analyzer to quickly determine particle size distribution and calculate Hardin relative breakage rate. The sampling location corresponds to the measuring point and the sampling mass is preferably 80g~120g to ensure representativeness and testing accuracy. This provides a quantitative basis for subsequent correction of in-situ penetration resistance parameters and effectively solves the problem of in-situ test parameter distortion caused by particle breakage in dredged coral sand.

[0069] Specifically, in step S3, the formula for calculating the corrected in-situ penetration resistance parameter is as follows:

[0070] ;

[0071] in, The parameter is the in-situ penetration resistance parameter, and Br is the particle breakage rate parameter. The coefficient representing the impact of particle breakage is . The value range is 0.2 to 0.5.

[0072] Specifically, the particle breakage influence coefficient The determination is based on a comprehensive analysis of the calcium carbonate content of the dredged coral sand, the strength of the parent rock, and the initial porosity; when the calcium carbonate content is greater than 90%, the parent rock strength is less than 20 MPa, and the initial porosity is greater than 1.4, Take 0.4~0.5; when the calcium carbonate content is 70%~90%, the parent rock strength is 20MPa~40MPa, and the initial void ratio is 1.2~1.4, Take a value of 0.2~0.3; when the calcium carbonate content is less than 70%, the parent rock strength is greater than 40 MPa, and the initial void ratio is less than 1.2, Take 0.2.

[0073] In this embodiment, firstly, representative coral sand samples are taken from the measuring points mentioned in step S1, and their calcium carbonate content, uniaxial compressive strength of the parent rock, and initial porosity are measured; then, the measured values ​​of the above three indicators are used as inputs, and determined according to the following rules. Specific values: When the calcium carbonate content is greater than 90%, the parent rock strength is less than 20 MPa, and the initial void ratio is greater than 1.4, it indicates high particle brittleness and extremely high sensitivity to breakage. Take a larger value of 0.4~0.5; when the calcium carbonate content is 70%~90%, the parent rock strength is 20MPa~40MPa, and the initial void ratio is 1.2~1.4, the fracturing sensitivity is moderate. The median value is taken as 0.2~0.3; when the calcium carbonate content is less than 70%, the parent rock strength is greater than 40 MPa, and the initial void ratio is less than 1.2, the fracturing sensitivity is low. Take the smaller value, 0.2. Confirm. Then, the Br measured in step S2 is compared with the Br measured in step S1. Substituting into the formula, we can calculate... This method reverses the process of removing the artificially inflated penetration resistance component caused by particle breakage from the measured values, restoring the equivalent original penetration blow count when particle breakage did not occur, thereby eliminating the interference of the breakage effect on the standard penetration test results.

[0074] This embodiment introduces a particle breakage influence coefficient. Furthermore, a graded and quantitative correspondence was established between the standard penetration test and calcium carbonate content, parent rock strength, and initial void ratio, enabling differentiated correction of in-situ penetration resistance parameters. This allows for the precise removal of the artificially inflated component in the measured blow count based on the fragmentation sensitivity of coral sand in different sections, ensuring that the corrected penetration blow count truly reflects the original compaction state of the soil before it is broken. This effectively eliminates the systematic interference of particle fragmentation effect on penetration resistance testing, significantly improving the applicability and evaluation accuracy of the standard penetration test in dredged coral sand.

[0075] Specifically, in step S4, the formula for calculating the comprehensive density fusion index is:

[0076] ;

[0077] Wherein, DI is the comprehensive density fusion index. These are the corrected in-situ penetration resistance parameters. For cone tip resistance, The shear wave velocity, Wet density, To preset in-situ penetration resistance parameters, To preset the cone tip resistance, For preset shear wave velocity, To preset the wet density, , , and Used to convert parameters into dimensionless relative values; , , , These are the weighting coefficients, and the sum of all weighting coefficients is 1; weighting coefficients The value range is 0.25~0.40. The value range is 0.20~0.35. The value range is 0.20~0.35. The value range is 0.10 to 0.20.

[0078] In this embodiment, the preset in-situ penetration resistance parameter The determination method involves selecting at least three qualified measuring points within the calibration area of ​​the evaluation region, whose bearing capacity has been verified by static load tests to meet design requirements and whose settlement observation values ​​meet deformation control standards, and calculating their corrected in-situ penetration resistance parameters. The arithmetic mean, as The preset cone tip resistance The determination method is to take the cone tip resistance of the qualified measuring point in the calibration area within the evaluation region. The arithmetic mean, as The preset shear wave velocity The determination method is to take the shear wave velocity of the qualified measuring points in the calibration area within the evaluation region. The arithmetic mean, as The preset wet density The determination method is to take the wet density of the qualified measuring points in the calibration area within the evaluation region. The arithmetic mean, as .

[0079] Specifically, the weighting coefficients are determined using principal component analysis or backpropagation neural network training based on static load test data from the calibration area or sampled indoor test data.

[0080] In this embodiment, a representative calibration area is first selected within the evaluation region, and at least three sets of measuring points are set up within the calibration area to simultaneously acquire data. , , and The measured values ​​were used to obtain the characteristic values ​​of the foundation bearing capacity through static load tests at each measuring point, or to obtain the relative density Dr through indoor relative density tests at the measuring points. The characteristic values ​​of the bearing capacity or Dr were used as the true characterization label values ​​of the compaction. Then, the label values ​​were used as the dependent variable, and... , , and For each independent variable, principal component analysis is used to determine the contribution ranking of each independent variable to the label value, and initial weights are assigned accordingly; or a backpropagation neural network is used, with multiple sets of calibration data as training sets for iterative training, until the network output error converges to a preset threshold, and finally the optimal solution of each weight coefficient is output.

[0081] The weighting coefficients determined using the above method satisfy the constraint that the summation equals 1, and all weighting coefficients are positive. After determining the weighting coefficients, they are embedded in the data fusion module. For the four types of parameters collected and corrected at each measuring point within the evaluation area, a weighted summation is performed with equal weights to calculate the DI value for each measuring point. The larger the DI value, the higher the overall compactness of the soil at that measuring point, providing a unified, multi-source information-integrated quantitative evaluation index for subsequent compactness level classification.

[0082] This embodiment establishes a multi-parameter weighted fusion model, which synergistically integrates four indicators: the corrected in-situ penetration resistance parameter, the cone tip resistance, the shear wave velocity, and the wet density. Using static load test data from the calibration area or indoor test data, principal component analysis or backpropagation neural network training is used to determine the weight coefficients of each indicator. This allows the fusion index to comprehensively reflect multi-dimensional information such as penetration resistance, wave velocity, and density, avoiding the one-sidedness and limitations of single-indicator evaluation, and effectively improving the comprehensiveness and accuracy of the compaction evaluation of dredged coral sand.

[0083] Specifically, in step S5, determining whether each measuring point meets the design requirements includes:

[0084] When the comprehensive density fusion index is greater than or equal to the sum of the target density value and the allowable deviation value, the density is determined to meet the design requirements;

[0085] When the comprehensive density fusion index is between the difference between the target density value and the allowable deviation value and the sum of the target density value and the allowable deviation value, the density is determined to meet the design requirements, and local reinforcement treatment is required.

[0086] When the comprehensive compactness fusion index is less than or equal to the difference between the target compactness value and the allowable deviation value, it is determined that the compactness does not meet the design requirements and the foundation treatment needs to be carried out again.

[0087] The allowable deviation value is 0.05 to 0.10 times the target density value. The bearing capacity requirements and deformation control standards for the dredged coral sand foundation in the engineering design documents are comprehensively determined based on the measured DI values ​​of the measuring points in the calibration area that meet the design requirements.

[0088] In this embodiment, the density level of each measuring point is classified according to the comparison results, specifically as follows: the density is divided into four levels: "dense," "medium-dense," "slightly dense," and "loose." Specifically, when the comprehensive density fusion index is greater than or equal to the sum of the target density value and the allowable deviation value, it is classified as a dense level; when the comprehensive density fusion index is between the difference between the target density value and the allowable deviation value and the sum of the target density value and the allowable deviation value, it is classified as a medium-dense level; when the comprehensive density fusion index is between the difference between the target density value and twice the allowable deviation value and the difference between the target density value and the allowable deviation value, it is classified as a slightly dense level; and when the comprehensive density fusion index is less than or equal to the difference between the target density value and twice the allowable deviation value, it is classified as a loose level. The dense level corresponds to meeting the design requirements, the medium-dense level corresponds to meeting the design requirements but requiring local reinforcement, and the slightly dense and loose levels correspond to not meeting the design requirements and requiring re-treatment of the foundation.

[0089] In this embodiment, the target compaction value is determined comprehensively based on the bearing capacity requirements and deformation control standards of the dredged coral sand foundation in the engineering design documents, combined with the measured values ​​of the DI at the control points that meet the design requirements within the calibration area. Specifically, no fewer than three control points within the calibration area are selected, whose bearing capacity has been verified to meet the design requirements by static load tests and whose settlement observation values ​​meet the deformation control standards. The arithmetic mean of the measured values ​​of the DI at these control points is taken as the target compaction value. When the coefficient of variation of the DI values ​​at each control point is greater than 0.15, the number of control points needs to be increased to no less than six before recalculation. The allowable deviation value is used to define the width of the transition interval between meeting the compaction requirements and not meeting the requirements. The method for determining it is to obtain it by multiplying the standard deviation of the DI values ​​at all points within the calibration area by a preset confidence coefficient. The confidence coefficient ranges from 1.0 to 2.0. When the importance level of the project is high or the foundation deformation control requirements are strict, the confidence coefficient takes a smaller value, and vice versa. The final value of the allowable deviation value does not exceed 0.10 times the target compaction value.

[0090] In this embodiment, the target density value The determination method is as follows: A calibration area is selected within the evaluation region. Static load tests are conducted on the measuring points within the calibration area to obtain the foundation bearing capacity, and settlement observations are performed. Measuring points whose foundation bearing capacity, verified by static load tests, meets the design requirements and whose settlement observation values ​​meet the deformation control standards are selected as compliance control measuring points. The arithmetic mean of the measured comprehensive density fusion index (DI) values ​​of all compliance control measuring points is taken as the standard. When the coefficient of variation of the DI value at each compliant control point is greater than 0.15, the number of compliant control points is increased to no less than six, and the value is recalculated. The method for determining the allowable deviation value Δ is as follows: Where σ is the standard deviation of DI values ​​at all measuring points within the calibration area, and k is the confidence coefficient, ranging from 1.0 to 2.0; a smaller value is taken when the project is of high importance or the foundation deformation control requirements are strict, and a larger value is taken otherwise; and .

[0091] This embodiment establishes a three-level compaction judgment standard: compliant, basically compliant, and non-compliant. The target compaction value is determined based on the measured DI values ​​of the compliant control points in the calibration area, and the allowable deviation value is determined based on the standard deviation and confidence coefficient of the DI values ​​of the test points in the calibration area. This makes the judgment threshold based on measured data and statistical basis, avoids the arbitrariness of empirical values, and realizes the accurate graded evaluation of the treatment effect of dredged coral sand foundation.

[0092] Specifically, based on the judgment results of each measuring point, the area covered by measuring points that meet the design requirements is marked as a qualified area, and the area covered by measuring points that do not meet the design requirements is marked as a substandard area. Specifically, for each measuring point, if the comprehensive density fusion index DI of that measuring point is greater than or equal to the target density value... The sum of the density index DI and the allowable deviation value Δ is used to mark the measuring point as a qualified measuring point; if the comprehensive density fusion index DI of the measuring point is less than or equal to the allowable deviation value Δ, then the measuring point is marked as a qualified measuring point. The difference between the measured point and Δ is used to mark the measured point as a non-compliant measured point. Based on this, all compliant measured points within the evaluation area are connected to form the boundary envelope of the compliant area, and all non-compliant measured points within the evaluation area are connected to form the boundary envelope of the non-compliant area. When the distance between adjacent compliant or non-compliant measured points is greater than twice the distance between measured points, no boundary connection is made between the adjacent measured points to avoid false continuous areas caused by interpolation errors, thereby forming spatial distribution markings of compliant and non-compliant areas within the evaluation area.

[0093] Specifically, in step S6, the comprehensive density fusion index (DI) of all measuring points is used as the data source. Ordinary Kriging interpolation or generalized Kriging interpolation is employed to spatially estimate locations within the evaluation area where no measuring points are located. Specifically, first, the semi-variogram of the DI values ​​at each measuring point is calculated and fitted with a theoretical model to determine the spatial variability parameters. Then, the fitted semi-variogram is used to perform a weighted linear combination of the DI values ​​of known measuring points surrounding each unknown point to calculate the optimal unbiased estimate for each unknown point. The weight coefficient of each known measuring point is determined based on its spatial distance from the unknown point and the semi-variogram model; measuring points that are closer and have stronger spatial correlation have greater weights. Finally, the measured DI values ​​and interpolated estimates at all measuring points are arranged according to spatial coordinates, and a contour line tracking algorithm is used to generate a density contour map covering the entire evaluation area. Based on the generated density contour map, the boundary of the substandard area marked in step S5 is superimposed on the contour map, the area inside the boundary is filled with a bright warning color, and "substandard area" is marked in the legend. This forms a density spatial distribution map that highlights the substandard area, providing an intuitive visual basis for project acceptance and zoned rectification.

[0094] Specifically, to further quantitatively evaluate the overall effectiveness of foundation treatment schemes, a calculation method for the Treatment Effectiveness Index (TEI) is also provided. This index achieves a quantitative comprehensive evaluation of the treatment effect of dredged coral sand foundations by integrating changes in in-situ penetration resistance parameters before and after foundation treatment, the increase in relative density, and the degree of control over particle fragmentation.

[0095] The formula for calculating the Treatment Effectiveness Index (TEI) is as follows:

[0096] ;

[0097] in, and These are the measured in-situ penetration resistance parameters before and after foundation treatment, respectively. and The relative densities are those before and after foundation treatment, respectively. The relative fracture rate of Hardin after foundation treatment; The maximum Hardin relative breakage rate. The initial particle size distribution and mineral composition of the dredged coral sand were determined in advance through indoor impact crushing tests.

[0098] The physical significance of TEI is as follows: This reflects the efficiency of the treatment process in improving soil penetration resistance; It reflects the actual degree of improvement in the soil compaction state before and after treatment; This factor reflects the acceptable degree of particle breakage during the treatment process. The closer this factor is to 1, the less breakage occurs, and the less damage the treatment process causes to the particle skeleton. Multiplying these three factors together reflects the overall effectiveness and rationality of the treatment plan.

[0099] In practical applications, the density grade classification results are combined with the Treatment Effectiveness Index (TEI) to comprehensively evaluate the foundation treatment effect of dredged coral sand. The specific evaluation criteria are as follows: when the TEI is greater than 0.80 and the density grade is determined to meet design requirements, the comprehensive evaluation result is that the treatment effect is qualified; when the TEI is between 0.50 and 0.80 and the density grade is determined to basically meet design requirements, the comprehensive evaluation result is that the treatment effect is average and requires local reinforcement; when the TEI is less than 0.50, the comprehensive evaluation result is that the treatment effect is unqualified and foundation treatment needs to be redone or the construction process optimized.

[0100] like Figure 2 As shown, Figure 2 This is a schematic diagram of the rapid compaction evaluation device for dredged coral sand according to an embodiment of this application.

[0101] A rapid compaction evaluation device for blown coral sand includes:

[0102] The multi-parameter acquisition module is used to acquire in-situ penetration resistance parameters, static cone penetration resistance parameters, shear wave velocity parameters, and soil density parameters at each measuring point.

[0103] The breakage rate determination module is used to perform particle size distribution analysis on soil samples taken from the test points and calculate particle breakage rate parameters.

[0104] The data correction module is used to correct the in-situ penetration resistance parameter according to the particle breakage rate parameter to obtain an equivalent original penetration resistance parameter that eliminates the influence of particle breakage.

[0105] The data fusion module is used to weight and fuse the equivalent original penetration resistance parameter with the static penetration resistance parameter, shear wave velocity parameter and soil density parameter to calculate the comprehensive compaction fusion index of each measuring point.

[0106] The grading module is used to compare the comprehensive density fusion index with the preset target density threshold, divide the density level of each measuring point and determine whether each measuring point meets the design requirements, and mark the qualified area and the unqualified area in the evaluation area according to the judgment result.

[0107] The spatial distribution output module is used to generate a spatial distribution map of density covering the evaluation area based on the comprehensive density fusion index of all measuring points using a spatial interpolation method, and to highlight the substandard areas in the spatial distribution map of density.

[0108] A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method.

[0109] Example 1: This example uses the density evaluation of coral sand foundation after dredging for an island airport runway as an example to illustrate the specific implementation process of the rapid density evaluation method for dredging coral sand provided by the present invention.

[0110] The airport runway reclamation area has a plan dimension of 200m × 50m. The calcium carbonate content of the reclaimed coral sand is 92%, the parent rock strength is 15MPa, the initial void ratio is 1.45, and the maximum void ratio is... Minimum porosity The foundation treatment employs the vibro-compaction method, with a designed target relative density. A rapid evaluation of the compaction of the treated fill material is now required.

[0111] S1. Rapid on-site acquisition of multi-parameter in-situ test data; according to... Figure 2 The layout scheme shown employs a grid-like arrangement of measuring points within the evaluation area. For the standard penetration test (SPT), measuring points are spaced 15m longitudinally and 10m laterally along the runway, totaling 77 points, to determine the in-situ penetration resistance parameter N. The static cone penetration test involves continuous penetration testing along three longitudinal lines, spaced 20m apart, to obtain continuous cone tip resistance. The depth distribution curve is obtained by taking the average value within the depth range of 3m to 5m as the representative value for that survey line. Five transverse survey lines are laid out using the multichannel surface wave analysis method, with a line spacing of 25m. Each survey line is equipped with 24 geophones, with a channel spacing of 2m. Surface wave data are acquired using a weighted vibration method, and the shear wave velocity is obtained through dispersion curve inversion. The test points for the nucleus-free density meter coincide with the test points for the standard penetration test (SPT). Wet density measurements are taken immediately after the SPT test. Measurements are taken to achieve simultaneous acquisition of multiple parameters.

[0112] The original test data of representative measuring points are shown in Table 1. Table 1 Original data of multi-parameter in-situ test of representative measuring points;

[0113] Table 1

[0114]

[0115] S2. Rapid determination of particle breakage rate: 100g sand samples were taken from each measuring point from SPT-01 to SPT-08, and particle size distribution was rapidly determined using a portable particle size analyzer. This instrument, based on the principle of laser diffraction, can complete particle size distribution measurement within 5 minutes. Based on the measurement results, the Hardin relative breakage rate Br of the sand sample at each measuring point was calculated. Taking measuring point SPT-01 as an example: Breakage potential before the test... Breaking potential after the test Therefore, Br = (41.2 - 28.5) / 28.5 = 0.446. The calculation results of Br at each measuring point are shown in Table 2.

[0116] Table 2 shows the results of Hardin's relative breakage rate determination at each measuring point;

[0117] Table 2

[0118]

[0119] S3. Correct the in-situ penetration resistance parameters; based on the calcium carbonate content of the dredged coral sand (92%, greater than 90%), the parent rock strength (15 MPa, less than 20 MPa), and the initial void ratio (1.45, greater than 1.4), determine the particle breakage influence coefficient. Using the modified formula The measured in-situ penetration resistance parameters at each measuring point were corrected. Taking SPT-01 as an example: =28×(1+0.45×0.446)=28×1.201=23.3. The correction results for each measuring point are shown in Table 3.

[0120] Table 3 shows the correction results for the in-situ penetration resistance parameters;

[0121] Table 3

[0122]

[0123] S4. Establish a multi-parameter fusion model; select three calibration areas within the evaluation region for static load tests and indoor sampling tests; according to Tables 1 and 3, the qualified test points are SPT-02, SPT-06, and SPT-08; first, determine the preset benchmark values ​​for each parameter. Based on the measured data of the qualified test points in the calibration area whose bearing capacity has been verified to meet the design requirements by static load tests, calculate the arithmetic mean of each parameter as the preset benchmark value:

[0124] =(28.6+31.0+26.6) / 3=28.7 hits;

[0125] =(15.2+16.8+14.5) / 3=15.5MPa;

[0126] =(310+325+305) / 3=313m / s;

[0127] =(1.95+1.97+1.96) / 3=1.96g / cm³.

[0128] The relative density Dr, as determined by indoor experiments, is used as the target output. , , , Principal component analysis was used to determine the weight coefficients of the input variables. The calculation showed that the contribution rate of the first principal component was 78.5%, and the corresponding weight coefficient was: , , , ,satisfy .

[0129] Substituting the above weighting coefficients into the multi-parameter fusion model The multi-parameter fusion index (DI) for each measuring point was calculated. The calculation results for each measuring point are shown in Table 4.

[0130] Table 4 shows the calculation results of the multi-parameter fusion index DI;

[0131] Table 4

[0132]

[0133] To facilitate comparison, a linear conversion relationship between DI and relative density Dr was established based on the test data from the calibration area. The test data from the calibration area shows that DI=0.65 corresponds to Dr=0.50, and DI=1.05 corresponds to Dr=0.90. Therefore, the linear conversion relationship is: Drest=(DI-0.65) / 0.40×0.40+0.50=(DI-0.65)+0.50=DI-0.15. From this, the estimated relative density of SPT-01 is Drest=0.859-0.15=0.709 (Note: This value is for illustrative purposes only; the actual value needs to be determined based on the actual calibration data. The normalized DI value itself can already serve as the basis for density ranking and grading, and there is no need for a mandatory conversion to Dr).

[0134] S5. Classify density levels; design target relative density. =0.75. Based on the measured DI values ​​of the benchmark test points (SPT-02, SPT-06, SPT-08) in the calibration area, the target compaction value was calculated. =(0.992+1.058+0.952) / 3=1.001. Take the allowable deviation value Δ=0.08× =0.080. The density grading standard is as follows:

[0135] DI≥1.081: The compaction degree meets the design requirement;

[0136] 0.921<DI<1.081: The compaction degree basically meets the design requirement, and local reinforcement is required;

[0137] DI≤0.921: The compaction degree does not meet the design requirement, and re-treatment is required.

[0138] According to the above criteria, SPT-01 (DI=0.859) is judged to have a compaction degree that does not meet the design requirement; SPT-04 (DI=0.909) is judged to have a compaction degree that does not meet the design requirement; SPT-02 (DI=0.992) and SPT-08 (DI=0.952) are judged to have a compaction degree that basically meets the design requirement; SPT-06 (DI=1.058) is judged to have a compaction degree that meets the design requirement.

[0139] S6. Output the spatial distribution map of compaction degree: Using the ordinary Kriging spatial interpolation method, taking the multi-parameter fusion index DI of 77 SPT measurement points as input data, and considering the anisotropic variogram characteristics, a spatial distribution map of compaction degree for the entire 200m×50m evaluation area is generated. The spatial distribution map is presented in the form of contour lines with a contour interval of 0.05 DI units, and compaction degree grade zones are identified by a color gradient (green for the meeting requirement zone, yellow for the basically meeting requirement zone, and red for the not meeting requirement zone). From the spatial distribution map, a low compaction degree zone can be intuitively identified in the west-central part of the runway, which corresponds to the water flow convergence and fine-grained sedimentation zone during the reclamation process, and local vibroflotation reinforcement treatment is required.

[0140] S7. Calculate the treatment effect index TEI:

[0141] ;

[0142] Wherein, are the measured standard penetration blow counts before and after treatment respectively, are the relative densities before and after treatment, is the Hardin relative breakage rate after treatment, is the maximum Hardin relative breakage rate

[0143] In the original reclaimed coral sand before treatment, the in-situ penetration resistance parameter of the representative area =8 blows, the relative density =0.35, and the maximum Hardin relative breakage rate =0.60. At the SPT-06 measurement point after treatment =38 blows, =0.78, =0.411. Calculation of the treatment effect index:

[0144] TEI=(38 / 8)×(0.78 / 0.35)×(1-0.411 / 0.60)=4.75×2.23×0.315=3.34;

[0145] Since the TEI is much greater than 0.80 and the density level is determined to meet the design requirements, the overall evaluation result is that the foundation treatment effect at this measuring point is qualified.

[0146] Example 2: This example uses the compaction evaluation of coral sand surcharge preloading treatment after reclamation at a port terminal as an example to illustrate the applicability of the method of the present invention under different foundation treatment conditions.

[0147] The land reclamation area behind the wharf has a plan dimension of 150m × 80m. The reclaimed coral sand has a calcium carbonate content of 78%, a parent rock strength of 30MPa, and an initial void ratio of 1.28. The foundation treatment adopts the surcharge preloading method, with a preloading load of 120kPa and a preloading period of 6 months. The design target relative density is... =0.70.

[0148] S1. Rapid on-site acquisition of multi-parameter in-situ test data;

[0149] Standard penetration test (SPT) measurement points were arranged in a 12.5m × 12.5m grid, with a total of 96 measurement points. Static cone penetration tests were conducted continuously along 5 longitudinal and 3 transverse measurement lines, with a line spacing of 15m–20m. Multichannel surface wave analysis (MSW) was performed using 8 measurement lines, with a line spacing of 20m. Nuclear density gauges and SPT measurement points were tested simultaneously.

[0150] S2. Rapidly determine particle breakage rate;

[0151] 100g sand samples were taken from 12 representative measuring points, and the particle size distribution was determined using a portable particle size analyzer. The Hardin relative breakage rate Br was calculated, and the results ranged from 0.25 to 0.38.

[0152] S3, Correct the in-situ penetration resistance parameters;

[0153] Based on a calcium carbonate content of 78% (70%~90%), a parent rock strength of 30 MPa (20 MPa~40 MPa), and an initial void ratio of 1.28 (1.2~1.4), the particle breakage influence coefficient was determined. Using the modified formula The measured in-situ penetration resistance parameters at each measuring point were corrected.

[0154] S4. Establish a multi-parameter fusion model;

[0155] First, determine the preset reference value of each parameter. According to the measured data of the qualified measuring points in the calibration area, the arithmetic mean of each parameter is calculated as the preset reference value: =29.0 blows, =14.5MPa, =300m / s, =1.95g / cm³ (Note: calculated according to the data of qualified measuring points in Table 5); 4 calibration areas are selected for static load test and sampling indoor test, and the back propagation neural network is used for training to determine the weight coefficient. The number of nodes in the input layer of the neural network is 4 ( , , , ), the number of nodes in the hidden layer is 8, and the number of nodes in the output layer is 1 (Dr). After training and verification, the determined weight coefficients are: , , , . Substitute the weight coefficients into the multi-parameter fusion model to calculate the multi-parameter fusion index DI of each measuring point.

[0156] The representative measuring point data and DI calculation results are shown in Table 5.

[0157] Table 5 shows the representative measuring point data and DI calculation results of the second embodiment;

[0158] Table 5

[0159]

[0160] S5. Divide the compactness grades; design the target relative density =0.70. According to the measured DI values of the qualified control measuring points in the calibration area, calculate the target compactness value =(0.992+1.052) / 2=1.022 (SPT-02 and SPT-05 are taken as qualified measuring points). Take the allowable deviation value Δ=0.07× =0.072. Division criteria:

[0161] DI≥1.094: the compactness meets the design requirement;

[0162] 0.950<DI<1.094: the compactness basically meets the design requirement, and local reinforcement is required;

[0163] DI≤0.950: the compactness does not meet the design requirement, and re-treatment is required.

[0164] According to the classification criteria, SPT-02 (DI=0.992) and SPT-04 (DI=0.918) are basically satisfied; SPT-05 (DI=1.052) is satisfied; and SPT-01 (DI=0.862), SPT-03 (DI=0.724) and SPT-06 (DI=0.784) are not satisfied.

[0165] S6. Output density spatial distribution map;

[0166] The generalized Kriging spatial interpolation method was adopted, using the DI values ​​of 96 SPT measurement points as input data. Considering the anisotropic consolidation characteristics caused by surcharge preloading (the longitudinal consolidation degree is higher than the transverse consolidation), an anisotropic variogram model was set (longitudinal range 80m, transverse range 50m) to generate a spatial distribution map of the density of the entire evaluation area. The spatial distribution map shows that the density of the wharf front area (close to the center of the preload) is relatively high, meeting or basically meeting the design requirements; the density of the rear edge area is relatively low, and there are areas that do not meet the design requirements, requiring additional compaction or vibro-compaction reinforcement.

[0167] S7. Calculate the Processing Effectiveness Index (TEI);

[0168] Before processing =6 hits =0.30, =0.55. At SPT-A05 after processing. =35 hits =0.75, =0.22. Calculate the treatment effect index:

[0169] TEI=(35 / 6)×(0.75 / 0.30)×(1-0.22 / 0.55)=5.83×2.50×0.60=8.75

[0170] Since the TEI is much greater than 0.80 and the density level is determined to meet the design requirements, the overall evaluation result is that the treatment effect is qualified. Compared with Example 1, the particle breakage rate caused by the surcharge preloading method is lower and the TEI is higher, indicating that the surcharge preloading method is superior to the vibratory compaction method in controlling particle breakage.

[0171] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A method for rapid evaluation of the compaction of dredged coral sand, characterized in that, include: Step S1: Set up measuring points in the evaluation area and collect in-situ test parameters at each measuring point. The in-situ test parameters include in-situ penetration resistance parameters, static cone penetration resistance parameters and shear wave velocity parameters obtained by standard penetration test, and soil density parameters obtained by nuclear density meter. Step S2: Take a soil sample at the measuring point, conduct a particle crushing test on the soil, determine the particle size distribution of the soil, and determine the particle crushing rate parameter of the soil based on the particle size distribution. Step S3: Use the particle breakage rate parameter to correct the in-situ penetration resistance parameter to obtain the equivalent original penetration resistance parameter that eliminates the influence of particle breakage. Step S4: The equivalent original penetration resistance parameter is fused with the static penetration resistance parameter, shear wave velocity parameter and soil density parameter to obtain the comprehensive compaction fusion index of each measuring point. Step S5: Compare the comprehensive density fusion index with the preset target density threshold, divide the density level of each measuring point according to the comparison result, and determine whether each measuring point meets the design requirements. Based on the determination results of each measuring point, mark the qualified area that meets the design requirements and the unqualified area that does not meet the design requirements in the evaluation area. Step S6: Based on the comprehensive density fusion index of all measuring points, a spatial interpolation method is used to generate a density spatial distribution map covering the evaluation area, and the substandard areas are highlighted in the density spatial distribution map.

2. The rapid density evaluation method for dredged coral sand according to claim 1, characterized in that, In step S1, the test points of the standard penetration test are arranged in a grid pattern, and the test points of the nuclear density meter coincide with the test points of the standard penetration test, so as to realize the synchronous acquisition of in-situ test data.

3. The rapid density evaluation method for dredged coral sand according to claim 1, characterized in that, In step S2, the formula for calculating the particle breakage rate parameter is: ； Wherein, Br is the particle breakage rate parameter, Bt is the breakage potential after the particle breakage test, and Bp is the breakage potential before the particle breakage test; the breakage potential Bp before the particle breakage test is the area enclosed by the soil particle size distribution curve and the particle size coordinate axis before the particle breakage test, and the breakage potential Bt after the particle breakage test is the area enclosed by the soil particle size distribution curve and the particle size coordinate axis after the particle breakage test. The breakage potential is obtained by integrating the content of particles with a particle size less than 0.074 mm and the particle size distribution data of each distribution interval.

4. The rapid density evaluation method for dredged coral sand according to claim 1, characterized in that, In step S3, the formula for calculating the corrected in-situ penetration resistance parameter is as follows: ； in, Br is the measured penetration blow count obtained at the measuring point through a standard penetration test, and Br is the particle breakage rate parameter. The coefficient representing the impact of particle breakage is . The value range is 0.2 to 0.

5.

5. The rapid density evaluation method for dredged coral sand according to claim 4, characterized in that, The particle breakage influence coefficient is determined comprehensively based on the calcium carbonate content of the dredged coral sand, the strength of the parent rock, and the initial porosity; when the calcium carbonate content is greater than 90%, the parent rock strength is less than 20 MPa, and the initial porosity is greater than 1.4, Take 0.4~0.5; when the calcium carbonate content is 70%~90%, the parent rock strength is 20MPa~40MPa, and the initial void ratio is 1.2~1.4, Take a value of 0.2~0.3; when the calcium carbonate content is less than 70%, the parent rock strength is greater than 40 MPa, and the initial void ratio is less than 1.2, Take 0.

2.

6. The rapid density evaluation method for dredged coral sand according to claim 1, characterized in that, In step S4, the formula for calculating the comprehensive density fusion index is: ； Wherein, DI is the comprehensive density fusion index. The corrected in-situ penetration resistance parameters. For cone tip resistance, The shear wave velocity, Wet density, To preset in-situ penetration resistance parameters, To preset the cone tip resistance, For preset shear wave velocity, To preset the wet density, , , and Used to convert parameters into dimensionless relative values; , , , These are the weighting coefficients, and the sum of all weighting coefficients is 1; weighting coefficients The value range is 0.25~0.

40. The value range is 0.20~0.

35. The value range is 0.20~0.

35. The value range is 0.10 to 0.

20.

7. The rapid density evaluation method for dredged coral sand according to claim 6, characterized in that, The weighting coefficients are determined using principal component analysis or backpropagation neural network training based on static load test data from the calibration area or sampled indoor test data.

8. The rapid density evaluation method for dredged coral sand according to claim 1, characterized in that, In step S5, it is determined whether each measuring point meets the design requirements, including: When the comprehensive density fusion index is greater than or equal to the sum of the target density value and the allowable deviation value, the density is determined to meet the design requirements; When the comprehensive density fusion index is between the difference between the target density value and the allowable deviation value and the sum of the target density value and the allowable deviation value, the density is determined to meet the design requirements, and local reinforcement treatment is required. When the comprehensive compactness fusion index is less than or equal to the difference between the target compactness value and the allowable deviation value, it is determined that the compactness does not meet the design requirements and the foundation treatment needs to be carried out again. The allowable deviation is 0.05 to 0.10 times the target density value. The target density value is determined comprehensively based on the bearing capacity requirements and deformation control standards of the dredged coral sand foundation in the engineering design documents, combined with the measured DI values ​​of the measuring points in the calibration area that meet the design requirements.

9. A rapid density evaluation device for blown coral sand, characterized in that, include: The multi-parameter acquisition module is used to acquire in-situ penetration resistance parameters, static cone penetration resistance parameters, shear wave velocity parameters, and soil density parameters at each measuring point; The breakage rate determination module is used to perform particle size distribution analysis on the soil sampled from the measuring point and calculate the particle breakage rate parameter. The data correction module is used to correct the in-situ penetration resistance parameter according to the particle breakage rate parameter to obtain an equivalent original penetration resistance parameter that eliminates the influence of particle breakage. The data fusion module is used to weight and fuse the equivalent original penetration resistance parameter with the static penetration resistance parameter, shear wave velocity parameter and soil density parameter to calculate the comprehensive compaction fusion index of each measuring point. The grading module is used to compare the comprehensive density fusion index with the preset target density threshold, divide the density level of each measuring point and determine whether each measuring point meets the design requirements, and mark the qualified area and the unqualified area in the evaluation area according to the judgment result. The spatial distribution output module is used to generate a spatial distribution map of density covering the evaluation area based on the comprehensive density fusion index of all measuring points using a spatial interpolation method, and to highlight the substandard areas in the spatial distribution map of density.

10. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed in a computer, causes the computer to perform the rapid compaction evaluation method for dredged coral sand as described in any one of claims 1-8.

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