Land area vibroflotation construction effect evaluation method

Abstract

The invention relates to the technical field of foundation treatment engineering, and discloses a land area vibroflotation construction effect evaluation method. The system comprises a construction parameter initial determination module, a test construction module, a detection point location planning module, a detection data processing and index calculation module, a construction parameter analysis and optimization module, a construction gridding module, a grid point location layout module, a grid evaluation index calculation module and a construction quality qualification determination module. According to the method, the comprehensiveness and representativeness of a detection result are ensured through a double-point layout scheme of the first type of point positions (central areas) and the second type of point positions (potential weak areas); a data smoothing processing rule of rolling window weighted average is introduced, so that the stability of data and the accuracy of an evaluation result are remarkably improved; a whole process from manufacturability test-parameter closed-loop optimization to formal construction-gridding evaluation is constructed, a standardized quality control system is established, and dynamic optimization and accurate matching of construction parameters are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foundation treatment engineering, and more particularly to a land vibroflotation construction effect evaluation method, which realizes closed-loop control of construction parameter optimization, construction quality verification and overall effect evaluation through CPT detection, and is suitable for vibroflotation compaction treatment scenes such as sand-filled foundation. BACKGROUND

[0002] The vibroflotation method is a common foundation treatment technology that improves the bearing capacity and anti-liquefaction ability of the foundation, reduces compressibility and settlement by high-frequency vibration and high-pressure water jet of the vibroflotation device to compact and reinforce loose foundation soil.

[0003] The accurate evaluation of the vibroflotation construction effect is a key link to ensure the quality of the foundation and directly affects the safety and stability of the subsequent superstructure. The application of CPT detection to the evaluation of the vibroflotation construction effect has become a common practice in the industry to verify the effect of foundation reinforcement by using hydraulic or mechanical devices to uniformly press a standard specification conical probe into the soil at a constant rate while continuously measuring the penetration resistance of the probe. By comparing the changes in parameters such as cone tip resistance before and after construction, the actual treatment effect of the foundation can be fully reflected.

[0004] The existing vibroflotation construction effect evaluation method has the following defects: The CPT detection point arrangement is not scientific: multiple detection points are only arranged near the vibroflotation point, ignoring the potential weak areas of vibroflotation compaction, such as the midpoint of the line connecting the vibroflotation points arranged in a regular triangle, resulting in detection results that cannot fully reflect the actual treatment effect of the foundation; The data processing accuracy is low: the qc value of the cone tip resistance obtained by CPT detection is mostly directly taken from a single point without considering the detection error in the depth direction, resulting in insufficient representation of the qc value and affecting the accuracy of the evaluation; The evaluation process is simplified: although CPT detection has been applied in foundation evaluation, it has not yet formed a standardized evaluation process of "pre-construction parameter determination-process test optimization-formal construction batch detection", which is difficult to meet the quality control requirements of high-precision sand-filled foundation vibroflotation construction.

[0005] Therefore, a method of scientific CPT detection point arrangement, high data processing accuracy and standardized evaluation process is needed to solve the above problems. SUMMARY

[0006] In order to overcome the above-mentioned defects of the prior art, the present application provides a land vibroflotation construction effect evaluation method to solve the problems existing in the background art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a land vibroflotation construction effect evaluation method, comprising: S1, select a process test area and perform pre-construction CPT detection, determine initial vibroflotation construction parameters based on the original data of cone tip resistance qc obtained at each depth; S2, perform vibroflotation compaction construction in the test area according to the initial vibroflotation construction parameters; S3, after construction, at least two post-construction CPT detection points are arranged in the test area, the at least two points include a first type of point located in the center area of the vibroflotation point arrangement mode, and a second type of point located in the midpoint area of the connecting line between adjacent vibroflotation points; S4, obtain the original data of cone tip resistance qc of each post-construction CPT detection point and perform data processing, and calculate an evaluation index representing the foundation treatment effect of the test area based on the processed data; S5, compare the evaluation index with the preset acceptance standard, if the requirements are met, the initial vibroflotation construction parameters are determined as the formal construction parameters, if not, adjust the initial construction parameters and repeat steps S2 to S5 until the evaluation index meets the preset acceptance standard, and the adjusted construction parameters are determined as the formal construction parameters; S6, in the formal construction area, perform vibroflotation construction according to the formal construction parameters, and divide the construction area into several evaluation grids with equal area and convenient quality control and traceability; S7, in each evaluation grid, at least two post-construction CPT detection points are arranged, and the types of the at least two points correspond to the first type of point and the second type of point in step S3; S8, obtain the original data of cone tip resistance qc of each point in each evaluation grid, and use the same calculation method as step S4 to obtain the comprehensive evaluation index of the grid; S9, compare the comprehensive evaluation index of each grid with the preset acceptance standard to determine whether the construction effect of a single grid is qualified, and further determine whether the overall vibroflotation construction effect is qualified.

[0008] The technical effects and advantages of the present application are: 1. The present application innovatively proposes a double-point layout scheme of "first type of point (center area) + second type of point (potential weak area)", which systematically covers the characteristic areas affected by vibroflotation compaction, can evaluate the direct compaction effect of vibroflotation points, and actively detects and verifies the thinnest area between adjacent points, fundamentally solving the problem of distorted evaluation results caused by one-sided point layout in traditional methods, and ensuring the comprehensiveness and representativeness of the detection results.

[0009] 2. This invention introduces a "rolling window weighted average" data smoothing rule to perform precise processing of the original cone tip resistance (qc) data in the depth direction. This method effectively eliminates the random fluctuations caused by single-point detection errors and local unevenness of the soil layer, making the data used for evaluation more reflective of the true average state of the soil, and significantly improving the stability of the data and the accuracy of the evaluation results.

[0010] 3. This invention constructs a standardized quality control system covering the entire process from "process testing - parameter closed-loop optimization" to "formal construction - grid-based evaluation". This system achieves dynamic optimization and precise matching of construction parameters through a closed-loop mechanism of "detection - analysis - adjustment - verification". By utilizing grid-based management and unified pass rate judgment, it achieves traceability and systematic control of quality, forming a proactive and forward-looking new model of quality management. Attached Figure Description

[0011] Figure 1 This is a flowchart of the present invention.

[0012] Figure 2 This is a diagram illustrating the vibratory compaction construction steps of the present invention.

[0013] Figure 3 This is a diagram showing the arrangement of the vibration compaction points according to the present invention.

[0014] Figure 4 This is a diagram showing the CPT point layout of the present invention. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The method for evaluating the effect of land vibratory compaction construction involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] This invention provides a method for evaluating the effect of land vibro-compaction construction, including a construction parameter initial determination module, a pilot construction module, a test point planning module, a test data processing and index calculation module, a construction parameter analysis and optimization module, a construction gridding module, a grid point layout module, a grid evaluation index calculation module, and a construction quality qualification judgment module.

[0017] Reference Figure 1 The specific implementation steps of the present invention include the following steps: S1. Select a process test area and conduct pre-construction CPT testing. Based on the original data of cone tip resistance qc at each depth obtained from the testing, determine the initial vibro-compaction construction parameters.

[0018] It should be specifically noted that the selection of the test area is as follows: Based on the distribution of the dredged strata on site, select a region with uniform geological conditions and representative characteristics as a process test area. The representativeness specifically refers to the fact that the thickness, particle size distribution, and density of the dredged sand in this region should be consistent with or close to the main conditions of the entire construction area, and the area should be controlled within 2000-3000㎡.

[0019] The specific steps of the pre-work CPT test are as follows: A1. Set up the pre-construction CPT points in the test area, that is, the center point of the vibratory compaction geometric layout pattern; For example, geometric arrangement patterns include equilateral triangles, squares, and hexagons; A2. Use an RTK measuring instrument to measure the ground elevation at the construction site and record the original ground elevation. A3. Perform CPT testing to obtain raw data of cone tip resistance (qc) at each depth and the initial distribution of the dredged sand strata; where each depth is from the surface to the design compaction depth; The initial distribution of the dredged sand strata includes at least the mud content Fc and particle size distribution of the dredged sand. The mud content Fc refers to the percentage of the mass of particles with a diameter less than 0.075 mm in the dredged sand, including soil and clay, to the total mass of the sand. The applicability of the vibratory compaction method is judged based on the mud content. When Fc ≤ 15%, it is considered applicable. If the mud content Fc > 15%, it is considered unapplicable, and other foundation treatment schemes such as vibratory replacement method should be considered.

[0020] The particle size distribution of the dredged sand directly affects the compactability of the soil and the energy input required to achieve optimal density. For well-graded sand, which contains both coarse and fine particles, it is easier to compact because fine particles can fill the pores of coarse particles. For this type of soil, the initial vibration spacing can be appropriately widened, and the vibration time can be appropriately shortened. For uniformly graded sand, which has a relatively uniform particle size, compaction is more difficult and requires greater compaction energy and a more effective radius of influence. For this type of soil, the initial parameters need to be smaller and the vibration time longer.

[0021] It should be specifically noted that the original cone tip resistance (qc) data at each depth obtained from pre-construction CPT testing are analyzed and preliminarily compared with the foundation liquefaction resistance (qc) target curve required in the design drawings or specifications. When the initial qc values ​​are generally lower than the target values, it indicates that the foundation needs reinforcement. Based on the original cone tip resistance (qc) data, the mud content (Fc) of the dredged sand, and the particle size distribution of the dredged sand, the initial vibro-compaction construction parameters are comprehensively determined. The initial vibro-compaction construction parameters include at least the following: The parameters include the spacing between vibratory points, the vibratory compactor model, the vibration duration, the length of the reinforced section, the water pressure, and the compaction current. For example, the vibratory points are arranged in an equilateral triangle with a side length of 2.0m; the vibratory compactor model is ZCQ-30; the vibration duration is 20-30 seconds; and the length of the reinforced section is 0.3-0.5m.

[0022] Reference Figure 2 S2. Vibro-compaction construction is carried out in the test area according to the initial vibro-compaction construction parameters.

[0023] It should be specifically noted that the vibratory compaction should be carried out in the test area strictly according to the parameters initially determined in S1. During the construction process, the working status of the vibratory compactor should be closely observed. If holes or cavitation appear around it, it indicates that the soil has been squeezed open. Crushed stone or coarse sand should be backfilled into the hole in time, and the thickness of each backfill should not exceed 500mm to ensure the compaction effect.

[0024] S3. After the construction is completed, at least two post-construction CPT test points shall be set up in the test area. The at least two points include a first type point located in the central area of ​​the vibratory compaction point layout pattern, and a second type point located in the midpoint area of ​​the line connecting adjacent vibratory compaction points in the vibratory compaction point layout pattern.

[0025] It should be noted that after construction is completed, in order to allow the pore water pressure in the soil to dissipate fully and the deformation to stabilize, a post-construction inspection should be carried out after an interval of at least 7 days.

[0026] The core purpose of deploying at least two post-construction CPT testing points is to cover the influence characteristic area of ​​vibratory compaction, specifically including: A first-class point, located in the central region of the geometric arrangement pattern formed by the vibratory compaction points, is used to evaluate the direct compaction effect of the vibratory compaction points; The first type of point completely overlaps with the pre-construction CPT point in step S1, and is used to compare the changes in soil mechanical properties before and after construction at the same location, i.e., the change in cone tip resistance qc. A second type of point is located in the midpoint area of ​​the line connecting adjacent vibratory compaction points. This area is a potential weak zone in compaction and is used to assess whether the effective radius of influence of vibratory compaction covers the entire area to ensure the uniformity of compaction effect.

[0027] S4. Obtain the original data of cone tip resistance qc at each of the post-construction CPT test points and perform data processing. Calculate the evaluation index representing the foundation treatment effect of the test area based on the processed data.

[0028] It should be noted that CPT testing is performed to obtain raw data of cone tip resistance (qc) at each depth of two points. The raw data of each point is smoothed along the depth direction to eliminate single-point detection errors caused by probe contact with foreign objects or local unevenness of the soil layer.

[0029] The smoothing process employs a rolling weighted average algorithm, which synthesizes the processed qc values ​​of the first and second type points at the same depth to calculate a single comprehensive evaluation index that represents the overall compaction effect of the test area. Specifically, for any depth h, the original cone tip resistance qc data within a 2X-meter depth range above and below h to h+X-meter are selected and weighted averaged to obtain the processed cone tip resistance value qc. h The specific calculation formula is as follows: ; Among them qc h This is the final cone tip resistance value at the target depth h after smoothing, i.e., after rolling weighted average processing; h represents the target depth where the value to be processed needs to be calculated; X is a real number greater than zero, representing the sampling radius upwards and downwards centered at the target depth h. The position ranges hX and h+X of the original data points involved in the calculation are defined, forming a sampling window with a total length of 2X meters centered at h. The preferred range of X is between 0.2m and 1.0m. For example, when X = 0.25 meters, the total length of the sampling window is 2X = 0.5 meters. qc h-X qc represents the original cone tip resistance value measured at depth hX. h+X The original cone tip resistance value measured at depth h+X; In (hX) / 2h and (h+X) / 2h, the 2 in the denominator is part of the weighting coefficient calculation formula, which together with h constitutes a depth-related weight allocator. In the formula, the 2 at the end represents the arithmetic mean of the weighted sum, which represents the sum of the two data points qc. h-X and QC h+X Perform a weighted summation; As the depth h increases, the weighting coefficient approaches 1 / 2, making the calculation results stable. At the same time, within the effective depth range, it can give slightly larger weights to the data of slightly deeper soil layers, which is consistent with the basic law that soil stress increases with depth, so that the processed data can better reflect the true average state of the soil.

[0030] It should be noted that the calculation formula has a clear physical meaning and computational stability when the depth h is sufficiently large. Therefore, this invention limits its application to the case where the depth h is greater than or equal to a set threshold H, which is preferably 2X meters. For shallow data with a depth less than H, direct arithmetic average or other conventional averaging methods can be used for processing.

[0031] Those skilled in the art will understand that the weighted average can also be in other forms, such as linear weighting, exponential weighting, etc. Any method that uses a fixed window to smooth the original qc data to eliminate single-point errors should fall within the protection scope of this invention.

[0032] It should be specifically noted that the evaluation index is the smoothed value qc of the two points at the same depth h. h Perform an arithmetic mean to calculate the average cone tip drag at that depth point, and then calculate the qc for all depth points. avg Connect them and draw a QC line representing the overall foundation treatment effect of the test area. avg -In-depth comprehensive evaluation index curve, QC avg The specific calculation formula is as follows: qc avg =(qc Ah +qc Bh ) / 2); Among them qc avg qc represents the average cone tip resistance at depth h. Ah The first type of point at the target depth h is the final cone tip resistance value after smoothing, i.e., rolling weighted average processing; qc Bh The second type of point is located at the target depth h, and the final cone tip resistance value is obtained after smoothing, i.e., rolling weighted average processing.

[0033] S5. Compare the evaluation indicators with the preset acceptance standards. If the requirements are met, the initial vibratory compaction construction parameters are determined as the formal construction parameters. If the requirements are not met, the initial construction parameters are adjusted and steps S2 to S5 are repeated until the evaluation indicators meet the preset acceptance standards. The adjusted construction parameters are then determined as the formal construction parameters.

[0034] It should be specifically noted that the comparison between the evaluation indicators and the preset acceptance standards will be as follows: The qc avg - Compare the depth comprehensive evaluation index curve with the preset foundation treatment acceptance standard curve, i.e., the qc target value curve for different depths; If within the entire design processing depth range, post-process QC avg If all values ​​are greater than or equal to the corresponding values ​​on the acceptance standard curve, it proves that the current construction parameters are qualified and they are determined as formal construction parameters. If at any depth, post-work QC avg If the value is lower than the target value, it indicates that the current construction parameters are unqualified, and the optimization process is initiated. The optimization process specifically includes: B1. Analysis; Scenario 1: If the QC value of the second type of point is lower than the target value, while the QC value of the first type of point meets the standard or exceeds the threshold ratio of the second type of point, such as exceeding 20% ​​of the second type of point; it indicates that the effective compaction radius of the vibratory compactor is insufficient and the spacing between the vibratory compaction points is too large, resulting in the failure to form an effective compaction effect overlap in the potential weak areas between adjacent vibratory compaction points. Scenario 2: If the qc values ​​of both the first and second type of points are lower than the target value, and the difference in value level does not exceed the threshold, it indicates that the compaction energy of a single vibratory compaction point is insufficient, resulting in the overall compaction from the center of the point to the periphery not meeting the requirements. The root cause is that the vibration time is too short, and the soil is not sufficiently compacted; the vibratory compactor power is too low or the lifting speed is too fast, resulting in insufficient compaction energy input per unit length. Scenario 3: If the QC value of the first type of point is lower than the target value, while the QC value of the second type of point meets or exceeds the threshold ratio of the first type of point, it indicates that the problem lies in the location of the oscillation point itself. Reasons include: Construction process issues: During construction at this specific first-class point, there were issues such as insufficient vibration and untimely or inadequate filling, which resulted in the formation of a void or loose area at that point. Geological anomaly: There are localized weak interlayers or obstacles below the center point, which affect the vibratory compaction effect.

[0035] B2. Adjustment; For scenario one, reduce the spacing between vibration points; for example, adjust it from 2.0m to 1.8m. For scenario two, extend the vibration dwell time; for example, from 20 seconds to 30 seconds; increase the encryption current setting or reduce the lifting speed of the vibrator; For scenario three, vibration was applied to the specific non-compliant first-type point and its surrounding area, and the construction process was checked to ensure that the fill material was filled according to specifications.

[0036] B3. Verification; Using the adjusted new parameters, repeat steps S2 to S5 in the test area until the obtained comprehensive evaluation indicators fully meet the acceptance criteria. Then, determine the adjusted construction parameters as the formal construction parameters.

[0037] S6. Within the formal construction area, vibro-compaction construction is carried out according to the formal construction parameters, and the construction area is divided into several evaluation grids of equal area that are easy to control and trace.

[0038] It should be specifically noted that throughout the entire formal construction area, the formal construction parameters optimized and finalized through the process testing phase must be strictly used for vibro-compaction construction to ensure the consistency and reliability of construction quality and avoid regional quality defects caused by improper parameters.

[0039] After construction is completed, the entire treatment area is systematically divided into several evaluation grids of equal area that facilitate quality control and traceability. The evaluation grids are preferably standard grids of equal area, and their size can be determined according to the total area of ​​the construction area, the complexity of the geological conditions, and the requirements for quality control accuracy. Each grid serves as an independent quality evaluation and management unit, and its construction records, test data, and evaluation results can be independently archived and traced. If a problem occurs in a grid, it can be accurately located, the responsibility can be clarified, and subsequent reinforcement treatment can be guided. As a preferred embodiment, the size of the standard evaluation grid can be 50 meters × 50 meters. Those skilled in the art will understand that other sizes can also be used, such as rectangular grids of 30 meters × 30 meters, 40 meters × 40 meters, 60 meters × 60 meters, or other shapes of grid units. As long as the purpose of regional quality management and traceability can be achieved, they should be considered to fall within the scope of protection of this invention.

[0040] S7. Within each of the evaluation grids, at least two post-construction CPT detection points are set up, and the types of the at least two points correspond to the first type of points and the second type of points described in step S3.

[0041] It should be specifically noted that the targeted deployment principles verified in the process testing phase of step S3 should be completely replicated and systematically extended to every quality assessment grid in the formal construction to ensure the uniformity of quality assessment standards and the comparability of results.

[0042] The first type of point is located in the central area of ​​the vibratory compaction point layout pattern within the evaluation grid, such as the center of an equilateral triangle, to check whether the direct compaction effect of the vibratory compaction points meets the expected standard, representing the best treatment effect achieved in this area.

[0043] The second type of point is located in the midpoint area of ​​the line connecting adjacent vibratory compaction points in the vibratory compaction point layout pattern within the evaluation grid, i.e., the potential weak area. This is to check whether the effective influence range of the compaction effect covers the entire area, verify the uniformity of the treatment, and prevent the existence of weak zones that have not been effectively reinforced.

[0044] It should be noted that the "correspondence" refers to the fact that the type, spatial relative position, and technical function of the post-construction CPT detection points deployed in each evaluation grid during the formal construction phase are consistent with the deployment scheme established during the process testing phase. For example, if the center point and the midpoint of the side line of an equilateral triangle are deployed during the process testing phase, then each grid during the formal construction phase should also contain at least these two types of points, so as to evaluate the optimal compaction effect and detect weak compaction areas, respectively.

[0045] S8. Obtain the original data of the tip resistance qc at each point within each evaluation grid, and calculate the evaluation index of this grid based on the said data. The evaluation index is the same as the evaluation index in step S5.

[0046] Specifically, for the original qc data of a single point, the same "rolling window weighted average method" as in step S4 is used for smoothing processing to eliminate single-point detection errors.

[0047] For the processed qc values at the same depth h of the first-type points and the second-type points within the same grid, the same algorithm as in step S4 is used for synthesis, and finally the comprehensive evaluation index of this grid - that is, the qc-depth curve is obtained. avg - depth curve.

[0048] It should be noted that in step S8, it is required that the evaluation index is the same as the evaluation index in step S5. The purpose is to ensure the high unity of the quality acceptance standard and the parameter optimization standard. In the formal construction stage, for the quality acceptance of each grid, the data processing flow and calculation formula used are exactly the same as those used in the process test stage to determine whether the construction parameters are qualified, eliminating the risk of quality misjudgment caused by inconsistent standards and enhancing the scientific nature of quality evaluation and the reliability of results.

[0049] S9. Compare the evaluation index of each grid with the preset acceptance standard to determine whether the construction effect of a single grid is qualified, and further determine whether the overall vibroflotation construction effect is qualified.

[0050] Specifically, the determination of whether the construction effect of a single grid is qualified is as follows: Compare the comprehensive evaluation index of each grid obtained in step S8, that is, the qc-depth curve, with the same preset acceptance standard used in step S5, that is, the qc target curve required by the design, depth by depth. avg - depth curve with the same preset acceptance standard used in step S5, that is, the qc target curve required by the design, for depth-by-depth comparison; Within all the designed treatment depth ranges, if the qc value of this grid is greater than or equal to the qc target value at the corresponding depth on the acceptance standard curve, it is qualified; avg If the qc value at any depth is lower than the target value, it is determined that the construction effect of this grid is unqualified; for unqualified grids, reinforcement measures need to be taken, such as adding vibroflotation in weak areas and re-constructing after adjusting parameters, etc., and re-conducting the CPT detection and evaluation of this grid after reinforcement, that is, repeating steps S7 - S9 until it meets the standard. If the qc value at any depth avg is lower than the target value, it is determined that the construction effect of this grid is unqualified; for unqualified grids, reinforcement measures need to be taken, such as adding vibroflotation in weak areas and re-constructing after adjusting parameters, etc., and re-conducting the CPT detection and evaluation of this grid after reinforcement, that is, repeating steps S7 - S9 until it meets the standard.

[0051] The determination of whether the overall vibroflotation construction effect is qualified is specifically as follows: After each grid meets the qualification standard, including grids that pass on the first attempt and those that pass after reinforcement, the overall effect is statistically analyzed and judged. The number of qualified grids in all evaluated grids is counted, and the qualification rate is calculated. The qualification rate refers to the percentage of qualified grids out of the total number of evaluated grids. Qualification rate = number of qualified grids / total number of grids × 100% If the calculated overall pass rate meets or exceeds the design requirements, the overall effect of the land vibro-compaction construction of this project is finally deemed to be qualified; in projects with extremely high safety standards, this requirement is usually 100%.

[0052] Example: The project involves port land development, with a foundation of dredged sand (mud content Fc=5%), and a fill thickness of approximately 4m; Design requirements: Surface layer 0.5m: Minimum relative compaction 90%, average 95%; For depths below 0.5m: The CPT test qc value must meet the acceptance curve (qc≥2.93MPa for a depth of 1m, qc≥3.56MPa for a depth of 2m, and qc≥3.80MPa for a depth of 3m).

[0053] The specific steps are as follows: Step 1: Pre-process CPT testing and initial parameter determination; Test area selection: A 2500㎡ area within the project area with uniform dredged fill thickness (4m) and continuous sand quality was selected as the process test area; Pre-construction CPT testing: One pre-construction CPT point was set up, and the average pre-construction elevation was measured by RTK at 2.5m; the initial QC data obtained from the CPT testing were: QC = 1.8MPa at depth 1m, QC = 2.2MPa at depth 2m, and QC = 2.8MPa at depth 3m (all lower than the target value); Initial parameter determination: Based on the characteristics of the dredged sand and the initial QC data, the following parameters are initially determined: Reference Figure 3 The spacing between vibratory impact points is 2m (equilateral triangle), and the vibratory impactor model is ZCQ-30. Water pressure 0.1~0.5MPa, compaction current 40~50A; Vibration lifting speed: 1.5 m / min; Vibration dwell time: 20 s; Prepare and submit the test plan.

[0054] Step 2: Process testing, CPT linkage, and parameter optimization; Test construction: The test area was constructed according to the initial parameters. During construction, a small amount of cavitation appeared around the vibratory compactor, and the filler was promptly added. Post-construction CPT testing: Two post-construction CPT points were set up 7 days after construction. Reference Figure 4 Point 1: Coincides with point 1 before construction, and the QC data is checked and processed according to S4.h : 1m=2.8MPa, 2m=3.3MPa, 3m=3.6MPa; Point 2: Midpoint of the edge line, qc after detection and processing according to the method described in S4 h : 1m=2.6MPa, 2m=3.2MPa, 3m=3.8MPa; Data processing and comparison: QC avg Values: 1m = 2.7MPa (< 2.93MPa), 2m = 3.25MPa (< 3.56MPa), 3m = 3.7MPa (< 3.8MPa), which do not meet the acceptance curve; Parameter adjustment: The cause was analyzed as "excessive spacing between points and insufficient compaction coverage". The parameters were adjusted as follows: spacing 1.5m, vibration time extended to 30s. Secondary verification: The test area was reconstructed according to the adjusted parameters, and the QC was measured by CPT after the second construction. avg Values: 1m = 3.05MPa, 2m = 3.75MPa, 3m = 4.05MPa (all meet the acceptance curve).

[0055] Step 3: Formal construction CPT batch testing and settlement assessment; Grid division: The project area (100,000 square meters) is divided into 40 standard grids of 50m × 50m; CPT detection and data processing: Point A (center point of an equilateral triangle) and point B (midpoint of the side line of an equilateral triangle) are set up in each grid. CPT detection is performed and processed according to "rolling 0.5m weighted average". Example: After processing, point A in grid 10 has the following qch values: 1m = 3.2MPa, 2m = 3.7MPa, 3m = 4.2MPa; After processing at point B, qch is: 1m = 3.5MPa, 2m = 4.0MPa, and 3m = 4.3MPa. qc_avg: 1m=3.35MPa, 2m=3.85MPa, 3m=4.25MPa (meets the acceptance curve); Judgment results: Grid 10 is qualified; 38 out of 40 grids are qualified on the first test, and 2 are qualified after vibration repair due to slightly low qc_avg (depth 2m qc_avg=3.3MPa<3.56MPa).

[0056] Step 4: Overall assessment and archiving.

[0057] Through the above description of the embodiments, those skilled in the art can clearly understand that the various embodiments of this application can be implemented by means of software or software combined with necessary general-purpose hardware platforms, and of course, they can also be implemented by hardware functions. Based on this understanding, the technical solution of this application, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. The software product is stored in a storage medium and includes several instructions to cause a computer device, such as including but not limited to a personal computer, server, or network device, to execute all or part of the steps of the method described in any embodiment of this application.

[0058] The foregoing has described exemplary embodiments of this application. It should be understood that the above exemplary embodiments are not restrictive but illustrative, and the scope of protection of this application is not limited thereto. It should be understood that those skilled in the art can make modifications and variations to the embodiments of this application without departing from the spirit and scope of this application, and such modifications and variations should be within the scope of protection of this application.

Claims

1. A method for evaluating the effectiveness of land-based vibro-compaction construction, characterized in that, Specifically, it includes: S1. Select a process test area and conduct pre-construction CPT testing. Based on the original data of cone tip resistance qc at each depth obtained from the testing, determine the initial vibro-compaction construction parameters. S2. Vibratory compaction construction is carried out in the test area according to the initial vibratory compaction construction parameters. S3. After the construction is completed, at least two post-construction CPT test points shall be set up in the test area. The at least two points include a first type point located in the central area of ​​the vibratory compaction point layout pattern, and a second type point located in the midpoint area of ​​the line connecting adjacent vibratory compaction points in the vibratory compaction point layout pattern. S4. Obtain the original data of cone tip resistance qc at each of the post-construction CPT test points and perform data processing. Calculate the evaluation index representing the foundation treatment effect of the test area based on the processed data. S5. Compare the evaluation indicators with the preset acceptance standards. If the requirements are met, the initial vibratory compaction construction parameters are determined as the formal construction parameters. If the requirements are not met, the initial construction parameters are adjusted and steps S2 to S5 are repeated until the evaluation indicators meet the preset acceptance standards. The adjusted construction parameters are then determined as the formal construction parameters. S6. Within the formal construction area, vibratory compaction is carried out according to the formal construction parameters, and the construction area is divided into several evaluation grids of equal area that are easy to control and trace. S7. Within each evaluation grid, at least two post-work CPT detection points are set up, and the types of the at least two points correspond to the first type of points and the second type of points described in step S3. S8. Obtain the raw data of cone tip resistance qc at each point within each evaluation grid, and use the same calculation method as in step S4 to obtain the comprehensive evaluation index of the grid. S9. Compare the comprehensive evaluation index of each grid with the preset acceptance standard to determine whether the construction effect of a single grid is qualified, and then determine whether the overall vibratory compaction construction effect is qualified.

2. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The specific steps of the pre-work CPT test are as follows: A1. Set up the pre-construction CPT points in the test area, that is, the center point of the vibratory compaction geometric layout pattern; A2. Use an RTK measuring instrument to measure the ground elevation at the construction site and record the original ground elevation. A3. Perform CPT testing to obtain the original data of cone tip resistance (qc) at each depth and the initial distribution of the dredged sand strata; where each depth is from the surface to the design compaction depth.

3. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The specific locations for setting up at least two post-construction CPT detection points include: A first-type point, located in the central area of ​​the geometric arrangement pattern formed by the vibro-compaction points, is used to evaluate the direct compaction effect of the vibro-compaction points; the first-type point completely overlaps with the pre-construction CPT point in step S1, and is used to compare the changes in soil mechanical properties, i.e., the change in cone tip resistance qc, at the same location before and after construction; a second-type point, located in the midpoint area of ​​the line connecting adjacent vibro-compaction points, is a potential weak area for compaction, and is used to evaluate whether the effective influence radius of vibro-compaction covers the entire area to ensure the uniformity of the compaction effect.

4. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The data processing specifically involves smoothing the raw data of each point along the depth direction. This smoothing process uses a rolling weighted average algorithm to synthesize the processed qc values ​​of the first and second types of points at the same depth, calculating a single comprehensive evaluation index that represents the overall compaction effect of the experimental area. Specifically, for any depth h, the raw data of the cone tip resistance qc within a 2X-meter depth range above and below h to h+X-meter are selected and weighted averaged to obtain the processed cone tip resistance value qc. h .

5. The method for evaluating the effect of land vibro-compaction construction according to claim 4, characterized in that: The cone tip resistance processing value qc h The specific calculation formula is as follows: ； Among them qc h This refers to the final cone tip resistance value at the target depth h after smoothing, i.e., rolling weighted averaging. It is applicable when the depth h is greater than a set threshold H, where H ≥ 2X meters. h is the target depth to be calculated; X is a real number greater than zero, representing the sampling radius upwards and downwards centered at the target depth h. The position ranges hX and h+X of the original data points participating in the calculation are defined, forming a sampling window centered at h with a total length of 2X meters; qc h-X qc represents the original cone tip resistance value measured at depth hX. h+X The original cone tip resistance value was measured at depth h+X.

6. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The specific evaluation indicators are as follows: The smoothed value qc of the two points at the same depth h h Perform an arithmetic mean to calculate the average cone tip drag at that depth point, and then calculate the qc for all depth points. avg Connect them and draw a QC line representing the overall foundation treatment effect of the test area. avg -In-depth comprehensive evaluation index curve, QC avg The specific calculation formula is: qc avg =(qc Ah +qc Bh ) / 2); where qc avg qc represents the average cone tip resistance at depth h. Ah The first type of point at the target depth h is the final cone tip resistance value after smoothing, i.e., rolling weighted average processing; qc Bh The second type of point is located at the target depth h, and the final cone tip resistance value is obtained after smoothing, i.e., rolling weighted average processing.

7. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The comparison of the evaluation indicators with the preset acceptance standards specifically involves: The qc avg - Compare the depth-based comprehensive evaluation index curve with the preset foundation treatment acceptance standard curve, i.e., the QC target value curves for different depths; if the post-construction QC is within the entire design treatment depth range... avg If all values ​​are greater than or equal to the corresponding values ​​on the acceptance standard curve, it proves that the current construction parameters are qualified and are determined as the formal construction parameters; if at any depth, the post-construction qc avg If the value is lower than the target value, it proves that the current construction parameters are not qualified, and the optimization process is initiated.

8. The method for evaluating the effect of land vibro-compaction construction according to claim 7, characterized in that: The optimization process specifically includes: B1. Analysis; Scenario 1: If the qc value of the second type of point is lower than the target value, while the qc value of the first type of point meets the standard or exceeds the threshold ratio of the second type of point, it indicates that the effective compaction radius of the vibratory compactor is insufficient, and the spacing between the vibratory compaction points is too large, resulting in the failure to form an effective compaction effect overlap in the potential weak areas between adjacent vibratory compaction points; Scenario 2: If the qc values ​​of both the first and second type of points are lower than the target value, and the difference between the values ​​does not exceed the threshold, it indicates that the compaction energy of a single vibratory compaction point itself is insufficient, resulting in the overall compaction from the center of the point to the periphery not meeting the requirements. The root cause is that the vibration dwell time is too long. Short, insufficient soil compaction, low vibratory compactor power, or excessively fast lifting speed, resulting in insufficient compaction energy input per unit length; Situation 3: If the QC value of the first type of point is lower than the target value, while the QC value of the second type of point meets the standard or exceeds the threshold ratio of the first type of point, it indicates that the problem lies in the location of the vibratory compaction point itself. The reasons include: Construction process problems: During construction at this specific first type of point, there was missed vibration, untimely or insufficient filling, resulting in the formation of a void or loose area at this point; Geological anomalies: There are local weak interlayers or obstacles below the center point, affecting the vibratory compaction effect. B2. Adjustments: For situation one, reduce the spacing between vibratory impact points; for situation two, extend the vibration dwell time, increase the set value of the densification current, or reduce the lifting speed of the vibratory impactor; for situation three, perform supplementary vibration on the specific non-compliant first-type point and its surrounding area, and check the construction process to ensure that the filling material is standardized. B3. Verification: Using the adjusted new parameters, repeat steps S2 to S5 in the test area until the obtained comprehensive evaluation indicators fully meet the acceptance criteria. Then, determine the adjusted construction parameters as the formal construction parameters.

9. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The evaluation grid is specifically as follows: Standard grids of equal area are used, with dimensions determined based on the total area of ​​the construction zone, the complexity of geological conditions, and the requirements for quality control precision. Each grid serves as an independent quality assessment and management unit, with its construction records, testing data, and assessment results all independently archived and traceable, supporting precise positioning and guiding subsequent reinforcement treatments.

10. The method for evaluating the effect of land vibro-compaction construction according to claim 1, characterized in that: The specific steps for determining whether the construction effect of a single grid is qualified are as follows: The comprehensive evaluation index of each grid obtained in step S8, i.e., qc avg - The depth curve is compared with the same preset acceptance criterion used in step S5, i.e., the qc target curve of the design requirements, depth by depth; within all design treatment depths, if the qc avg value of this grid is greater than or equal to the qc target value at the corresponding depth on the acceptance criterion curve, it is qualified; if the qc avg value at any depth is lower than the target value, it is determined that the construction effect of this grid is unqualified; for unqualified grids, reinforcement measures are carried out, and after reinforcement, the CPT detection and evaluation of this grid are carried out again, i.e., steps S7 - S9 are repeated until it meets the standard; The specific steps for determining whether the overall vibratory compaction construction effect is qualified are as follows: After each grid meets the qualification standard, including grids that pass the first time and those that pass after reinforcement, the overall effect is statistically analyzed and judged. The number of qualified grids in all evaluated grids is counted, and the qualification rate is calculated. The qualification rate refers to the percentage of qualified grids out of the total number of evaluated grids. Qualification rate = number of qualified grids / total number of grids × 100%. If the calculated overall qualification rate meets or exceeds the design requirements, the overall effect of the land vibro-compaction construction of this project is finally judged to be qualified. Usually, 100% is required.

Images