Method and device for measuring the compactness of embankment material
By combining CT technology and digital image processing with the calculation of soil particle volume ratio under optimal moisture content, the problems of long testing cycle and low accuracy of compaction degree of earth-rock dams and dikes have been solved, and efficient and accurate compaction degree measurement has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA FIRST METALLURGICAL GROUP
- Filing Date
- 2023-07-24
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies for detecting the compaction of earth-rock dams and embankments suffer from problems such as long testing cycles and easily affected accuracy. In particular, the drying method is inefficient and its application is limited without a nucleus density meter in moisture content testing.
By combining CT technology with digital image processing, the volume ratio of soil particles can be calculated by determining the CT scan image of soil samples at the optimal moisture content, simplifying the compaction degree measurement formula and avoiding the drying process.
It improves detection efficiency and ensures the accuracy and precision of compaction measurement, especially for measuring cohesive soil particles, overcoming the limitations of traditional methods.
Smart Images
Figure CN116990330B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of soil compaction measurement technology, and in particular to a method and apparatus for measuring the compaction of soil used in embankment construction. Background Technology
[0002] According to the compaction testing methods described in standards such as DL / T 5129-2001 "Construction Specification for Roller-Compacted Earth-Rock Dams" and GB / T 50123-2019 "Standard for Geotechnical Testing Methods," the commonly used method for compaction testing of earth-rock dams and embankments is the pit testing method. When calculating compaction, it is necessary to accurately and quickly test the moisture content of the soil in the test pit. In moisture content testing, the most common method in engineering is the drying method, which involves completely drying the soil in an electric oven, typically for 6-8 hours. The soil mass is measured before and after drying, and the moisture content and dry density are calculated. The ratio of the dry density to the maximum dry density is the compaction degree of the fill material. Currently, there are also other compaction testing methods such as nucleus-free densitometers. Although nucleus-free densitometers are faster and more environmentally friendly than traditional methods, their application in soil quality testing has revealed some drawbacks, such as limited measurement range, high environmental requirements, and susceptibility to accuracy issues. Improper calibration or interference from other factors can affect the accuracy of the measurement results.
[0003] In recent years, with the development of CT technology, it has been widely used in geotechnical engineering. For example, CN115266781A discloses a process for measuring the compaction degree of subgrade soil, including preparing multiple soil samples; scanning the multiple soil samples with a CT scanner to obtain multiple initial CT values; calculating the standard CT value corresponding to the standard maximum dry density using the multiple initial CT values; and the compaction degree being the ratio of the initial CT value to the standard CT value. However, since the compacted soil sample includes three phases (i.e., solid, liquid, and gas) of pores, pore water, and soil particles, the calculated total CT value is larger than the actual value due to the greater porosity and higher water content of the soil material after on-site compaction.
[0004] Therefore, there is an urgent need to establish a calculation method that can quickly detect the compaction degree of soil, and that has both high detection speed and high accuracy. Summary of the Invention
[0005] To address the issue of poor cycle time in testing the compaction degree of fill soil using the drying method, this invention combines CT technology to provide a method with high measurement efficiency and accuracy.
[0006] To achieve the above objectives, the present invention provides a method for measuring the compaction degree of embankment soil, comprising,
[0007] Determine the optimum moisture content of the soil material at the site, and obtain the soil sample and its CT scan image at the optimum moisture content. Determine the volume of soil particles in the soil sample at the optimum moisture content based on the CT scan image of the soil sample at the optimum moisture content.
[0008] In the embankment area, soil samples and their CT scan images were obtained for the soil layer to be analyzed. The volume of soil particles in the soil sample was determined based on the CT scan images of the soil layer to be analyzed.
[0009] The compaction degree of the soil layer to be analyzed for embankment construction is determined by the ratio of the volume of soil particles in the soil sample to the volume of soil particles in the field soil sample at the optimum moisture content.
[0010] Among them, the sampling volumes of the field soil sample and the soil sample of the soil layer to be analyzed are equal at the optimum moisture content.
[0011] Furthermore, the optimal moisture content of the soil material at the site was determined based on an indoor compaction test.
[0012] Furthermore, the same scanning parameters were used when acquiring CT scan images of field soil samples at the optimal moisture content and when acquiring CT scan images of soil samples from the soil layer to be analyzed.
[0013] Furthermore, image processing and data statistics are performed when acquiring CT scan images of soil samples at the optimum moisture content and when acquiring CT scan images of soil samples from the soil layer to be analyzed. Specifically, this includes...
[0014] Filtering and denoising, thresholding and binarization of CT images, and counting of pixels.
[0015] Furthermore, the sampling volumes of the field soil sample and the soil sample from the soil layer to be analyzed at the optimum moisture content are equal, ensuring this by using ring cutters of the same specifications.
[0016] This invention also provides a device for measuring the compaction degree of embankment soil, comprising,
[0017] The optimal moisture content unit is used to determine the optimal moisture content of the soil material in the field and to acquire CT scan images of the soil samples in the field at the optimal moisture content. Based on the CT scan images of the soil samples in the field at the optimal moisture content, the volume of soil particles in the soil samples in the field at the optimal moisture content is determined.
[0018] The soil sample unit is used to acquire CT scan images of soil samples from the embankment area to be analyzed, and to determine the volume of soil particles in the soil sample based on the CT scan images of the soil samples to be analyzed.
[0019] The compaction unit is used to determine the compaction degree of the soil layer to be analyzed for embankment construction based on the ratio of the volume of soil particles in the soil sample of the soil layer to be analyzed to the volume of soil particles in the field soil sample at the optimum moisture content.
[0020] Among them, the sampling volumes of the field soil sample and the soil sample of the soil layer to be analyzed are equal at the optimum moisture content.
[0021] Furthermore, the scanning parameters of the CT scan images of the soil samples at the optimal moisture content obtained by the optimal moisture content unit and the CT scan images of the soil samples of the soil layer to be analyzed obtained by the soil sample unit are the same.
[0022] Furthermore, the CT scan images of the soil samples at the optimal moisture content obtained by the optimal moisture content unit and the CT scan images of the soil samples to be analyzed obtained by the soil sample unit are also processed and statistically analyzed.
[0023] Furthermore, the device also includes an output unit for outputting the compaction degree of the soil material in the soil layer to be analyzed for embankment construction.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] 1. This invention simplifies the formula for measuring compaction using the drying method by using CT technology. Under the same sampling volume, the compaction of the embankment soil is determined by the ratio of the volume determined by the CT scan image of the soil sample at the optimum moisture content to the volume determined by the CT scan image of the soil layer to be analyzed. This eliminates the need to dry the sample, thus improving the detection efficiency.
[0026] 2. For small-sized cohesive soil particles, existing indoor physical experiments cannot measure the volume of soil particles in the sample. This invention uses CT scanning combined with digital image processing technology to measure the volume of soil particles, which has the advantages of high measurement accuracy and high data accuracy. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 A flowchart of a method for measuring the compaction degree of embankment soil material according to an embodiment of the present invention is shown;
[0029] Figure 2 A schematic diagram of a device for measuring the compaction degree of embankment soil is shown in an embodiment of the present invention. Detailed Implementation
[0030] The commonly used oven-drying method for measuring compaction degree refers to the ratio of the dry density of a soil sample taken from the construction site and measured after drying to constant weight to the maximum dry density obtained by standard compaction in the laboratory. The calculation formula is as follows:
[0031]
[0032] Where, ρ d ρ is the dry density of the compacted soil on site. dmax The maximum dry density obtained by indoor standard compaction;
[0033]
[0034]
[0035] therefore,
[0036] If the same volume of sample is taken after the compaction test and after the on-site backfill compaction, then the degree of compaction is the ratio of soil particle mass.
[0037] The concept of this invention addresses the problems of short effective construction time for dike filling (limited to the annual dry season), numerous layers of cohesive soil used in dike construction, and long existing compaction testing cycles. Through analysis of existing compaction measurement principles: since the specific gravity of soil particles does not vary significantly and the compaction test and the on-site fill soil source are the same, it is assumed that the specific gravity of soil particles remains unchanged.
[0038]
[0039] Therefore, compaction degree can be simplified as the ratio of soil particle volume in an equal volume after on-site backfill compaction to that after laboratory compaction. Obtaining the volume of on-site backfill after compaction and that of laboratory compaction using CT technology has the advantages of high efficiency and high accuracy, ensuring the accuracy of compaction degree measurement.
[0040] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0041] like Figure 1 As shown, in one embodiment of the present invention, a method for measuring the compaction degree of embankment soil is provided, including the following steps:
[0042] S101. Determine the optimum moisture content of the soil material at the site, and obtain the soil sample and its CT scan image at the optimum moisture content. Determine the volume of soil particles in the soil sample at the optimum moisture content based on the CT scan image of the soil sample at the optimum moisture content.
[0043] Specifically, the optimum moisture content of the soil was first determined based on indoor compaction tests. Indoor compaction tests were then conducted on soil samples at the optimum moisture content. After compaction, samples were taken using a ring cutter and subjected to CT scans to obtain CT images. Subsequently, each CT scan image underwent corresponding image processing and data statistics, mainly including filtering and denoising, thresholding and binarization of the CT images, and counting the number of pixels in the soil particles. The total number of pixels in all soil particles represents the volume of soil particles in the sampled soil.
[0044] Among them, at least three sets of CT scan images of the soil samples at the optimum moisture content were tested to obtain the average number of pixels of the soil samples at the optimum moisture content.
[0045] S102. Obtain soil samples and their CT scan images in the embankment area, and determine the volume of soil particles in the soil samples based on the CT scan images of the soil samples to be analyzed.
[0046] Using a ring cutter of the same specifications as in step S101, soil samples of the soil layer to be analyzed were obtained in the embankment area, ensuring that the volume of soil particles in the soil sample to be analyzed was consistent with that in the field soil sample at the optimum moisture content in step S101. After sampling, the samples were CT scanned to obtain CT images. Subsequently, each CT scan image was processed and statistically analyzed, using the same method as in step S101. The average number of pixels in the soil sample to be analyzed was obtained.
[0047] Meanwhile, to ensure the accuracy of CT measurements, the same scanning parameters are used when scanning images in steps S101 and S102.
[0048] S103. Determine the compaction degree of the soil material of the soil layer to be analyzed based on the ratio of the volume of soil particles in the soil sample of the soil layer to be analyzed to the volume of soil particles in the field soil sample at the optimum moisture content.
[0049] The compaction degree of the soil layer to be analyzed for embankment construction is determined by the ratio of the average number of pixels of the soil sample to be analyzed obtained in step S102 to the average number of pixels of the field soil sample at the optimum moisture content obtained in step S101, as shown in the following formula:
[0050]
[0051] Among them, X sX represents the average number of pixels in the soil sample to be analyzed. s ' is the average number of pixels in the field soil sample at the optimum moisture content.
[0052] like Figure 2 As shown, one embodiment of the present invention also provides a device for measuring the compaction degree of embankment soil, comprising,
[0053] The optimal moisture content unit is used to determine the optimal moisture content of the soil material in the field and to acquire CT scan images of the soil samples in the field at the optimal moisture content. Based on the CT scan images of the soil samples in the field at the optimal moisture content, the volume of soil particles in the soil samples in the field at the optimal moisture content is determined.
[0054] The soil sample unit is used to acquire CT scan images of soil samples from the embankment area to be analyzed, and to determine the volume of soil particles in the soil sample based on the CT scan images of the soil samples to be analyzed.
[0055] The compaction unit is used to determine the compaction degree of the soil layer to be analyzed for embankment construction based on the ratio of the volume of soil particles in the soil sample of the soil layer to be analyzed to the volume of soil particles in the field soil sample at the optimum moisture content.
[0056] The output unit is used to output the compaction degree of the embankment soil material;
[0057] Among them, the sampling volumes of the field soil sample and the soil sample of the soil layer to be analyzed are equal at the optimum moisture content.
[0058] In summary, this invention simplifies the formula for measuring compaction using the drying method by employing CT technology. Under the same sampling volume, the compaction degree of the embankment soil is determined by the ratio of the volume determined by the CT scan image of the soil sample at the optimum moisture content to the volume determined by the CT scan image of the soil layer to be analyzed. This eliminates the need for drying the sample, thus improving detection efficiency. For small-sized cohesive soil particles, existing indoor physical experiments cannot measure the volume of soil particles in the sample. This invention uses CT scanning combined with digital image processing technology to measure the volume of soil particles, offering advantages such as high measurement accuracy and high data accuracy.
[0059] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method of measuring the degree of compaction of an embankment material, characterized in that, include, The optimum moisture content of the soil material in the field was determined by indoor compaction test, and the soil sample and its CT scan image at the optimum moisture content were obtained. The volume of soil particles in the soil sample at the optimum moisture content was determined by the CT scan image of the soil sample at the optimum moisture content. In the embankment area, soil samples and their CT scan images were obtained for the soil layer to be analyzed. The volume of soil particles in the soil sample was determined based on the CT scan images of the soil layer to be analyzed. The compaction degree of the soil layer to be analyzed for embankment construction is determined by the ratio of the volume of soil particles in the soil sample to the volume of soil particles in the field soil sample at the optimum moisture content. Among them, the sampling volumes of the field soil sample and the soil sample of the soil layer to be analyzed are equal at the optimum moisture content.
2. The embankment soil compaction degree measuring method according to claim 1, characterized by, The optimal moisture content of the soil material at the site was determined based on indoor compaction tests.
3. The embankment soil compaction degree measuring method according to claim 1, characterized by, The same scanning parameters were used when obtaining CT scan images of soil samples at the optimum moisture content and when obtaining CT scan images of soil samples from the soil layer to be analyzed.
4. The embankment soil compaction degree measuring method according to claim 1, characterized by, When acquiring CT scan images of soil samples at the optimum moisture content and soil samples from the soil layer to be analyzed, image processing and data statistics are also performed, specifically including: Filtering and denoising, thresholding and binarization of CT images, and counting of pixels.
5. The embankment soil compaction measurement method according to claim 1, characterized by, The sampling volumes of the field soil sample and the soil sample from the soil layer to be analyzed are equal at the optimum moisture content, ensuring this by using ring cutters of the same specifications.
6. A device for measuring the degree of compaction of embankment material, characterized in that include, The optimum moisture content unit is used to determine the optimum moisture content of the soil material in the field based on the indoor compaction test, and to obtain the CT scan image of the soil sample in the field at the optimum moisture content. Based on the CT scan image of the soil sample in the field at the optimum moisture content, the volume of soil particles in the soil sample in the field at the optimum moisture content is determined. The soil sample unit is used to acquire CT scan images of soil samples from the embankment area to be analyzed, and to determine the volume of soil particles in the soil sample based on the CT scan images of the soil samples to be analyzed. The compaction unit is used to determine the compaction degree of the soil layer to be analyzed for embankment construction based on the ratio of the volume of soil particles in the soil sample of the soil layer to be analyzed to the volume of soil particles in the field soil sample at the optimum moisture content. Among them, the sampling volumes of the field soil sample and the soil sample of the soil layer to be analyzed are equal at the optimum moisture content.
7. The embankment soil compactness measuring apparatus according to claim 6, characterized by The CT scan images of the soil samples at the optimal moisture content obtained by the optimal moisture content unit and the CT scan images of the soil samples of the soil layer to be analyzed obtained by the soil sample unit have the same scanning parameters.
8. The embankment soil compactness measuring apparatus according to claim 6, wherein The CT scan images of the soil samples at the optimal moisture content obtained by the optimal moisture content unit and the CT scan images of the soil samples to be analyzed by the soil sample unit are also processed and statistically analyzed.
9. The embankment soil compactness measuring apparatus according to claim 6, wherein It also includes an output unit for outputting the compaction degree of the soil material in the soil layer to be analyzed for embankment construction.