Quality management method for improved soil

Abstract

To provide a quality management method for improved soil capable of enhancing efficiency of quality evaluation of the improved soil.SOLUTION: A quality management method for improved soil comprises continuously measuring, by fluorescence X-ray analysis, calcium content of the improved soil produced by mixing soil with an improvement material while the improved soil is being transported, and evaluating the strength of the improved soil based on measurement results.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a quality control method for improved soil. [Background technology]

[0002] Conventionally, improved soil is prepared by mixing soil with an improvement material in, for example, pile construction, ground improvement work, and soil modification work for excavated soil. As a quality control method for such improved soil, for example, Patent Document 1 discloses a method for controlling the quality of improved soil by measuring the calcium content in the improved soil using X-ray diffraction analysis and evaluating the quality of the improved soil based on the measurement results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6886363 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in this quality control method for improved soil, it is necessary to pretreat the improved soil in order to homogenize it before evaluating its quality. Therefore, it is desirable to improve the efficiency of quality evaluation of improved soil. [Means for solving the problem]

[0005] A quality control method for improved soil that solves the above problem includes continuously measuring the calcium content of improved soil, which is made by mixing soil with an improvement material, by fluorescent X-ray analysis while the soil is being moved, and evaluating the strength of the improved soil based on the measurement results. [Effects of the Invention]

[0006] According to the present invention, the quality evaluation of improved soil can be made more efficient. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a front view showing the improved soil quality control system of the first embodiment. [Figure 2] FIG. 2 is a top view showing the rotation device and the sample of the first embodiment. [Figure 3] FIG. 3 is a flowchart showing the improved soil quality control process of the first embodiment. [Figure 4] FIG. 4(A) is an explanatory diagram showing a comparative example of the quality evaluation results of improved soil, and FIG. 4(B) is an explanatory diagram showing an example of the quality evaluation results of improved soil. [Figure 5] FIG. 5 is a front view showing the improved soil quality control system of the second embodiment. [Figure 6] FIG. 6 is an explanatory diagram showing the relationship between the quality evaluation results of the improved soil in the second embodiment and the measurement distance between the laser measurement unit and the sample. [Figure 7] FIG. 7 is an explanatory diagram showing the relationship between the quality measurement time of improved soil and the measurement distance between the laser measurement unit and the sample in the second embodiment. [Figure 8] FIG. 8 is a flowchart showing the improved soil quality control process of the second embodiment. [Figure 9] FIG. 9 is a front view showing the improved soil quality control system of the third embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing the relationship between the quality measurement time of the improved soil, the quality evaluation result of the improved soil, and the measurement distance between the laser measurement unit and the sample in the third embodiment. [Figure 11] FIG. 11 is a flowchart showing the improved soil quality control process of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] An embodiment of the quality control method for improved soil will be described. <Improved soil quality control system 10> As shown in Figures 1 and 2, the improved soil quality control system 10 is a system that controls the quality of improved soil by adopting a quality control method for improved soil. Improved soil is produced by mixing soil with an improvement material. The improvement material contains lime. The lime contains calcium, such as calcium oxide, calcium hydroxide, and calcium carbonate. Improved soil is soil whose strength is improved by mixing soil with lime as the moisture contained in the soil evaporates.

[0009] The improved soil quality control system 10 includes a rotating device 11. The rotating device 11 includes a base 12 and a rotating table 13. The rotating table 13 is disposed above the base 12. The rotating table 13 is rotatable about a central axis C relative to the base 12 by a driving force from a rotation drive unit (not shown). The central axis C is an axis that extends in the vertical direction.

[0010] A sample 31 can be placed on the turntable 13. The turntable 13 rotates the placed sample 31. The sample 31 is prepared by filling a dish-shaped container 32 having a predetermined height with improved soil 33 in a dispersed state. The sample 31 is placed at a position where the center of the sample 31 overlaps with the central axis C when viewed from above.

[0011] The turntable 13 rotates at a predetermined rotation speed. The rotation speed may be, for example, 20 degrees per second. As a result, the turntable 13 rotates so that it completes one rotation every 18 seconds. In this embodiment, the turntable 13 rotates continuously, but may also rotate intermittently if it stops at each measurement period. In this embodiment, the turntable 13 rotates one revolution for each evaluation of the sample 31, but may also rotate multiple revolutions.

[0012] As shown in Fig. 1, the improved soil quality control system 10 includes a measuring device 21. The measuring device 21 is a device that measures the quality of the improved soil 33 by X-ray fluorescence analysis. The measuring device 21 measures the quality of the improved soil 33 at each measurement period. The measurement period may be, for example, one second.

[0013] The measuring device 21 includes a laser measuring unit 22. The laser measuring unit 22 irradiates the improved soil 33 with X-rays. The laser measuring unit 22 detects secondary X-rays (characteristic X-rays) generated by irradiating the improved soil 33 with X-rays as an X-ray count value. The X-ray count value is a value corresponding to the calcium content.

[0014] The laser measurement unit 22 is disposed at a position spaced a height H above the turntable 13 in the vertical direction. As a result, the laser measurement unit 22 is disposed at a position spaced a measurement distance D above the sample 31 in the vertical direction. The sample 31 is assumed to be filled with improved soil 33 up to the height of the container 32. In this way, the laser measurement unit 22 can measure the quality of the improved soil 33 without coming into contact with the sample 31 placed on the turntable 13. The measurement distance D may be 5 mm.

[0015] 2, the laser measurement unit 22 measures the quality of the improved soil 33 in a measurement area 34. The measurement area 34 is a circular area centered at a position radially away from the central axis C by a radius R. The measurement area 34 may be a circular area with a diameter of 10 mm, for example.

[0016] In this way, while the sample 31 rotates with the rotation of the turntable 13, the measuring device 21 measures the quality of the improved soil 33 at each measurement cycle, targeting multiple measurement areas 34 corresponding to a predetermined angle. Because the sample 31 rotates with the rotation of the turntable 13, the measurement areas 34 become multiple areas along the measurement reference position 35. The measurement reference position 35 is a circular position spaced a radius R from the central axis C.

[0017] It is preferable that the measurement area 34 is an area in which the areas to be continuously imaged do not overlap and the intervals between the areas to be continuously imaged are small, based on the rotation speed of the turntable 13, the measurement period measured by the measurement device 21, and the measurement distance D from the laser measurement unit 22 to the sample 31.

[0018] In this embodiment, the sample 31 rotates at 20 degrees per second, and the laser measurement unit 22 is spaced 5 mm from the improved soil 33, and the measurement device 21 measures the quality of the improved soil 33 18 times at 20 degree intervals, but this is not limited to this.

[0019] The measuring device 21 includes a control unit 23. The control unit 23 controls the measuring device 21. The control unit 23 is mainly configured with a microcontroller. The microcontroller may include, for example, a processor, a memory, an input interface, and an output interface, which are connected to each other via a bus.

[0020] The control unit 23 controls the measurement by the laser measurement unit 22. The control unit 23 may be capable of communicating with the rotation device 11. The control unit 23 may output a control signal to the rotation device 11 to rotate the turntable 13 at a predetermined rotation speed.

[0021] <Improved soil quality control process> The improved soil quality control step will now be described with reference to Fig. 3. The improved soil quality control step is a step carried out by adopting a quality control method for the improved soil 33.

[0022] As shown in FIG. 3, an improved soil preparation step is carried out in step S10. In the improved soil preparation step, an operator prepares improved soil 33 by mixing soil with an improvement material. Specifically, a predetermined amount of improvement material is mixed with a predetermined amount of soil. As a specific example, 3 50 kg of improvement material is mixed with 1 m 3 100kg or 150kg of amendment may be mixed for each soil.

[0023] In step S11, a sample collection step is carried out in which an operator collects the prepared improved soil 33. Then, in step S12, a sample filling step is carried out in which an operator fills the collected improved soil 33 into a container 32. Then, the operator places the container 32 filled with improved soil 33 on the turntable 13.

[0024] In step S13, a continuous measurement process is carried out. Specifically, the control unit 23 rotates the turntable 13 at a predetermined rotation speed. While the turntable 13 is rotating at the predetermined rotation speed, the control unit 23 irradiates the improved soil 33 with X-rays using the laser measurement unit 22 and detects the X-ray count value at each measurement cycle. In this way, the control unit 23 continuously measures the quality of the improved soil 33 for multiple measurement areas 34.

[0025] In step S14, a calcium content calculation step is performed. In the drawing, the calcium content calculation step is referred to as a Ca content calculation step. In the calcium content calculation step, the control unit 23 calculates the calcium content based on the measurement results from the continuous measurement step. In particular, in the calcium content calculation step, the control unit 23 calculates the average value of the X-ray count values as the measurement results from the continuous measurement step. Then, the control unit 23 calculates the calcium content corresponding to the average value of the X-ray count values.

[0026] In this way, while the improved soil 33 is rotated around the central axis C, the calcium content is continuously measured by fluorescent X-ray analysis at a position vertically away from the improved soil 33, targeting a measurement area 34 radially away from the central axis C, which is the center of rotation.

[0027] In step S15, a strength estimation process is performed. In the strength estimation process, the control unit 23 evaluates the strength of the improved soil 33 based on the measurement results. Specifically, the control unit 23 calculates the strength of the improved soil 33 based on a relational expression between the calcium content and the strength of the improved soil 33. This relational expression is based on the measurement distance D and the amount of improvement material to be mixed with a predetermined amount of soil. The control unit 23 then evaluates the quality of the improved soil 33 based on whether the strength of the improved soil 33 is within an acceptable range.

[0028] <Comparative Examples and Examples> Next, a comparative example and an example will be described with reference to FIG. 4. FIG. 4(A) is a diagram showing a comparative example, and FIG. 4(B) is a diagram showing an example. In the comparative example, the result of measuring X-ray count values using fluorescent X-ray analysis at a predetermined location on the sample 31 without rotating the sample 31 is shown. In the example, the result of continuously measuring X-ray count values using fluorescent X-ray analysis at a rotated sample 31 is shown. In the comparative example and the example, similarly, 3 The measurement results are obtained when improved soil 33, which is made by mixing 50 kg of improvement material with the soil, is used and the measurement distance D is 5 mm.

[0029] As shown in Fig. 4(A), in the comparative example, the X-ray count values were measured at six arbitrary locations, designated Measurement A to Measurement F, on Sample 31 before and after homogenization. In this case, the measurement results showed that the measured X-ray count values were uniform in Sample 31 after homogenization compared to Sample 31 before homogenization, in terms of both average and standard deviation. In other words, in the comparative example, homogenization of Sample 31 was necessary to improve the accuracy of the measurement results.

[0030] The pretreatment for homogenization includes a drying step for drying the improved soil 33. The pretreatment includes a crushing step for crushing the dried improved soil 33. The pretreatment includes a stirring step for stirring the crushed improved soil 33.

[0031] As shown in Fig. 4(B), in the example, the X-ray count value was measured while rotating the sample 31. In this case, the measurement results showed that there was no significant difference in the measured X-ray count value between the sample 31 before homogenization and the sample 31 after homogenization. Furthermore, the X-ray count value of the example was approximately the same as that of the sample 31 after homogenization in the comparative example.

[0032] As can be seen from the examples, the quality control method for improved soil 33 of this embodiment does not drastically reduce the accuracy of the quality evaluation of improved soil 33, even if pretreatment is not performed. Therefore, in this embodiment, the quality evaluation of improved soil 33 can be performed without pretreatment.

[0033] <Actions and Effects of the First Embodiment> The operation and effects of the first embodiment will be described. (1-1) The calcium content of the improved soil 33 is continuously measured by X-ray fluorescence analysis while the improved soil 33 is being rotated. The strength of the improved soil 33 is evaluated based on the measurement results. In this way, X-ray fluorescence analysis allows for analysis of each element contained in the improved soil 33, and is less susceptible to the influence of the state of the improved soil 33 compared to X-ray diffraction analysis. Furthermore, the strength of the improved soil 33 can be evaluated based on the measurement results of multiple measurement areas 34 as the improved soil 33 rotates. By continuously measuring the calcium content across multiple measurement areas 34 over a wide range, the accuracy of the calcium content measurement can be maintained without pre-treating the improved soil 33 to homogenize it. This improves the efficiency of the quality evaluation of the improved soil 33. Furthermore, the elimination of pre-treatment equipment, such as a dryer and a pulverizer, reduces the cost of evaluating the quality of the improved soil 33.

[0034] (1-2) While the improved soil 33 is rotated around the central axis C, the calcium content is continuously measured by X-ray fluorescence analysis at positions radially away from the central axis C, which is the center of rotation. Therefore, the strength of the improved soil 33 can be evaluated based on the measurement results in multiple measurement areas 34 that are evenly allocated as the improved soil 33 rotates. This makes it possible to maintain the accuracy of calcium content measurement without pre-treating the improved soil 33 to homogenize it. Therefore, the quality evaluation of the improved soil 33 can be made more efficient.

[0035] (1-3) While the improved soil 33 is rotated around the central axis C, the calcium content is continuously measured by X-ray fluorescence analysis at a position vertically spaced from the improved soil 33. Therefore, by using X-ray fluorescence analysis, the calcium content can be measured from a position vertically spaced from the improved soil 33, and the improved soil 33 can also be rotated smoothly. This makes it possible to maintain the accuracy of calcium content measurement without pre-treating the improved soil 33 to homogenize it. Therefore, the quality evaluation of the improved soil 33 can be made more efficient.

[0036] [Second embodiment] Next, a second embodiment will be described. In the following description, the same configuration as in the previously described embodiment will be omitted or simplified, and the configuration different from the previously described embodiment will be mainly described.

[0037] 5, in the second embodiment, the measuring device 21 may include a distance detection unit 24. The distance detection unit 24 detects the measurement distance D between the laser measurement unit 22 and the improved soil 33. This makes it possible to determine the state in which the improved soil 33 is filled in the container 32 as the sample 31, based on the measurement distance D detected by the distance detection unit 24. The distance detection unit 24 may detect the measurement distance D by irradiating a laser.

[0038] The distance detection unit 24 detects the measured distance D at a cycle shorter than the measurement cycle of the laser measurement unit 22, but may also be synchronized with the measurement by the laser measurement unit 22 and detect the measured distance D at least at each measurement cycle of the laser measurement unit 22. In the drawing, the distance detection unit 24 is provided outside the laser measurement unit 22 to facilitate understanding of the invention, but it may be provided at any position where the measured distance D can be detected.

[0039] 6, graph 41 shows that the measured X-ray count value decreases as the measurement distance D increases. For this reason, the calcium content corresponding to the measurement distance D is measured by correcting the measured X-ray count value based on the measured measurement distance D and the reference distance D0.

[0040] 7, the measurement distance D is measured at each measurement cycle, but the difference between the measurement distance D and the reference distance D0 becomes large during the period indicated by the symbol T1. Even in such a case, the calcium content corresponding to the measurement distance D can be measured by correcting the X-ray count value based on the measurement distance D.

[0041] <Improved soil quality control process> 8, in the improved soil quality control process, a measurement distance continuous detection process is performed in step S16. In the measurement distance continuous detection process, the control unit 23 continuously detects the measurement distance D. The measurement distance continuous detection process may be performed in parallel with the continuous measurement process of step S13.

[0042] In the measurement distance continuous detection process, the control unit 23 detects the measurement distance D at each measurement cycle in synchronization with the measurement by the laser measurement unit 22. In this way, the measurement distance D in the vertical direction from the improved soil 33 is continuously detected while the improved soil 33 is rotated.

[0043] In step S14, a calcium content calculation process, the control unit 23 calculates a correction value corresponding to the measurement distance D. Then, the control unit 23 calculates the calcium content according to the measurement distance D based on the continuously measured X-ray count values and the calculated correction value.

[0044] In this case, when the measurement distance D is longer than the reference distance D0, the control unit 23 corrects the X-ray count value to increase it. When the measurement distance D is shorter than the reference distance D0, the control unit 23 corrects the X-ray count value to decrease it. In this way, the continuously measured calcium content is corrected based on the continuously detected measurement distance D.

[0045] <Actions and Effects of the Second Embodiment> The operation and effects of the second embodiment will be described. (2-1) While the improved soil 33 is rotated around the central axis C, the measurement distance D from the improved soil 33 in the vertical direction is continuously detected. The continuously measured calcium content is corrected based on the measurement distance D. Therefore, even if the measurement distance D varies depending on the state of the improved soil 33 filled in the container 32, the calcium content can be measured based on the measurement distance D from the improved soil 33. This makes it possible to maintain the accuracy of calcium content measurement without pre-treating the improved soil 33 to homogenize it. Therefore, the quality evaluation of the improved soil 33 can be made more efficient.

[0046] [Third embodiment] Next, a third embodiment will be described. 9, in the third embodiment, the improved soil quality control system 10 may be able to adjust the position of the laser measurement unit 22 relative to the turntable 13 between a first position P1 and a second position P2. The first position P1 is a position where the height of the laser measurement unit 22 relative to the turntable 13 is a first height H1. The second position P2 is a position where the height of the laser measurement unit 22 relative to the turntable 13 is a second height H2. In particular, the improved soil quality control system 10 may be able to adjust the position of at least one of the rotation device 11 and the measurement device 21 in the vertical direction.

[0047] As a result, a first continuous measurement process may be performed with the measurement distance D adjusted to a first measurement distance D1, and a second continuous measurement process may be performed with the measurement distance D adjusted to a second measurement distance D2. The first measurement distance D1 is shorter than the second measurement distance D2. As a specific example, the first measurement distance D1 may be 5 mm, and the second measurement distance D2 may be 8 mm. Note that in FIG. 9, the second measurement distance D2 is shown longer than the first measurement distance D1 to facilitate understanding of the invention.

[0048] The first continuous measurement step is a step of measuring the X-ray count value when the turntable 13 rotates for the first time. The first continuous measurement step is a step of measuring the X-ray count value for calculating the calcium content.

[0049] The second continuous measurement process is a process of measuring the X-ray count value when the turntable 13 rotates for the second time. The second continuous measurement process is a measurement process for estimating the state of the improved soil 33 filled in the container 32 by comparing it with the first continuous measurement process. In the first continuous measurement process and the second continuous measurement process, the X-ray count value is measured in a measurement area 34 centered at the same position.

[0050] 10, the case where the measurement distance D is the first measurement distance D1 is shown in graph 42, and the case where the measurement distance D is the second measurement distance D2 is shown in graph 43. In the first continuous measurement process, according to graph 42, the X-ray count value is measured as 0 at the timings shown by symbols T2 to T6. In the second continuous measurement process, according to graph 43, the X-ray count value is measured as 0 at the timings shown by symbols T2 to T10.

[0051] In this way, at the timings shown by symbols T2 to T6, even if the measurement distance D changes, the X-ray count value is measured as 0. In this case, it can be assumed that the measurement area 34 where the X-ray count value is measured as 0 is not filled with improved soil 33.

[0052] Furthermore, at the timings shown by symbols T7 to T10, when the measurement distance D is the second measurement distance D2, the X-ray count value is measured as 0, but when the measurement distance D is the first measurement distance D1, the X-ray count value is measured as greater than 0. In this case, it can be estimated that improved soil 33 has been filled, but a sufficient amount of improved soil 33 has not been filled.

[0053] <Improved soil quality control process> 11, in the improved soil quality control process, a first continuous measurement process is performed in step S13. In the first continuous measurement process, the control unit 23 measures the X-ray count value as the first measurement result when the measurement distance D is the first measurement distance D1.

[0054] Next, in step S17, a second continuous measurement step is performed. In the second continuous measurement step, the control unit 23 measures the X-ray count value as the second measurement result in a state where the measurement distance D is the second measurement distance D2.

[0055] In step S14, a calcium content calculation step, control unit 23 calculates the calcium content based on the first measurement result and the second measurement result. In particular, in the calcium content calculation step, control unit 23 calculates the calcium content based on whether the X-ray count values corresponding to the first measurement result and the second measurement result are 0 or not.

[0056] Specifically, the control unit 23 assumes that measurement areas 34 where the X-ray count value is measured as 0 in both the first measurement result and the second measurement result are not filled with improved soil 33. In such cases, the control unit 23 excludes the X-ray count value from the measurement target.

[0057] As a specific example, if there are two measurement areas 34 where the X-ray count value is 0 in both the first measurement result and the second measurement result, the control unit 23 excludes those measurement results from the measurement target. As a result, the control unit 23 calculates the average value of the X-ray count value for the 16 first measurement results, excluding the two measurement results from the 18 measurement results.

[0058] Furthermore, the control unit 23 estimates that a sufficient amount of improved soil 33 has not been filled in the measurement area 34 where the X-ray count value was measured as 0 in the second measurement result but the X-ray count value was measured as greater than 0 in the first measurement result. In such a case, the control unit 23 calculates a correction value for correcting the X-ray count value.

[0059] Then, the control unit 23 corrects, based on the correction value, the first measurement result corresponding to the measurement region 34 where the X-ray count value was measured as 0 in the second measurement result but the X-ray count value was measured as greater than 0 in the first measurement result. In this case, the control unit 23 corrects so as to increase the X-ray count value.

[0060] Furthermore, the control unit 23 presumes that measurement areas 34 where the X-ray count values are greater than 0 in both the first and second measurement results are filled with a sufficient amount of improved soil 33. In such cases, the control unit 23 calculates the average value of the X-ray count values for the first measurement results.

[0061] In this way, the continuously measured calcium content is corrected based on the first measurement result measured at the first measurement distance D1 and the second measurement result measured at the second measurement distance D2. This correction includes a correction to exclude the measurement target and a correction of the X-ray count value itself.

[0062] <Actions and Effects of the Third Embodiment> The operation and effects of the third embodiment will be described. (3-1) While rotating the improved soil 33 around the central axis C, the calcium content is continuously measured by X-ray fluorescence analysis at a position vertically separated by a first measurement distance D1 from the improved soil 33 and at a position vertically separated by a second measurement distance D2 from the improved soil 33. The continuously measured calcium content is corrected based on the first measurement result measured at the position separated by the first measurement distance D1 and the second measurement result measured at the position separated by the second measurement distance D2. This allows the calcium content to be measured according to the state in which the improved soil 33 is filled. This maintains the accuracy of calcium content measurement without requiring pretreatment of the improved soil 33 to homogenize it. This therefore improves the efficiency of quality evaluation of the improved soil 33.

[0063] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0064] In the second embodiment, when the measurement distance D is equal to or greater than a predetermined upper limit distance, a correction may be performed to exclude the measurement results of the measurement area 34 where the measurement distance D is equal to or greater than the predetermined upper limit distance from the measurement target.When the measurement distance D is equal to or less than a predetermined lower limit distance, a correction may be performed to exclude the measurement results of the measurement area 34 where the measurement distance D is equal to or less than the predetermined lower limit distance from the measurement target.

[0065] In the second embodiment, as long as the measurement region 34 and the region for detecting the measurement distance D are associated with each other, the measurement region 34 and the region for detecting the measurement distance D may be different regions for each measurement cycle. As a specific example, the measurement region 34 and the region for detecting the measurement distance D may be located on either side of the central axis C. In this way, as the sample 31 rotates around one revolution, 18 measurement regions 34 are associated with the measurement distance D.

[0066] In the third embodiment, a correction value for correcting the X-ray count value may be calculated based on the difference between the first measurement result and the second measurement result. Specifically, if the difference between the first measurement result and the second measurement result is not within the allowable range, the object may be excluded from the measurement.

[0067] In the third embodiment, the improved soil quality control system 10 may include an adjustment drive unit that adjusts the height H of the laser measurement unit 22 relative to the turntable 13. The adjustment drive unit may be a motor. That is, the improved soil quality control system 10 may adjust the height H of the laser measurement unit 22 relative to the turntable 13 using the driving force from the adjustment drive unit. Alternatively, the improved soil quality control system 10 may manually adjust the height H of the laser measurement unit 22 relative to the turntable 13.

[0068] The rotation speed of the turntable 13, the measurement cycle by the laser measurement unit 22, and the measurement distance D may be any combination. In such a case, although the measurement accuracy by the laser measurement unit 22 tends not to decrease depending on the rotation speed of the turntable 13, a combination that enables measurement without changing the moisture content of the sample 31 is preferable. It is preferable that the elapsed time from the start to the end of the measurement is within a predetermined time. As a specific example, it is preferable to rotate the turntable 13 at a rotation speed faster than 1 mm / sec and perform continuous measurement with the laser measurement unit 22 so that the measurement is completed within 5 minutes.

[0069] The control unit 23 may calculate the calcium content corresponding to the X-ray count values in the multiple measurement areas 34, and then calculate the average calcium content. In other words, the calcium content may be continuously measured by X-ray fluorescence analysis while the improved soil 33 is being moved. Furthermore, the strength of the improved soil 33 may be evaluated based on the average calcium content value for the multiple measurement areas 34.

[0070] In the improved soil quality control process, the calcium content calculation process may be performed in parallel with the continuous measurement process. This allows the average value of the X-ray count values to be calculated for each measurement period based on the X-ray count values measured for each measurement period. The calcium content is then calculated for each measurement period based on the average value of the X-ray count values.

[0071] The improved soil quality control system 10 may include a display unit that displays the measurement results. The display unit may be provided in the measuring device 21, or may be provided separately from the measuring device 21. The display unit displays an image based on a signal from the control unit 23. The display unit may display the quality display results of the improved soil 33 itself, such as the strength evaluation results of the improved soil 33. The display unit may display the X-ray count value measured at each measurement cycle as the measurement result. The display unit may display the calcium content measured at each measurement cycle as the measurement result. The display unit may display the calcium content measured at each measurement cycle in a graphed format. The strength evaluation of the improved soil 33 may not be performed by the control unit 23, but may be performed by the evaluator himself based on the calcium content.

[0072] The control unit 23 may be provided in the rotation device 11. The control unit 23 may include a first control unit provided in the measurement device 21 and a second control unit provided in the rotation device 11. In this case, the functions of the control unit 23 may be divided and installed in the first control unit and the second control unit.

[0073] The improved soil quality control system 10 may be provided with a linearly moving moving table instead of the rotating device 11. In other words, the calcium content of the improved soil 33 may be continuously measured by X-ray fluorescence analysis while the improved soil 33 is moving, without having to rotate it.

[0074] The improved soil 33 may be prepared by mixing soil containing gravel with an improvement material. That is, the soil used to prepare the improved soil 33 may contain gravel or may be gravel itself. The improvement material may include cement.

[0075] The phrase "at least any" used herein means one or more of the desired options. As an example, when the number of options is two, the phrase "at least any" used herein means only one option or both options. As another example, when the number of options is three or more, the phrase "at least any" used herein means only one option or any combination of two or more options.

[0076] [Note] Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below. (A) The quality control method for improved soil does not include drying the improved soil before continuously measuring the calcium content.

[0077] (B) The quality control method for improved soil does not include grinding and stirring the improved soil before continuously measuring the calcium content. (C) The quality control method for improved soil includes evaluating the strength of the improved soil based on the average calcium content measured continuously.

[0078] (D) A quality control method for improved soil includes: rotating the improved soil around a central axis along the vertical direction, continuously measuring the calcium content by fluorescent X-ray analysis at a position that is a first measurement distance away from the improved soil in the vertical direction and at a position that is a second measurement distance away from the improved soil in the vertical direction; and correcting the continuously measured calcium content based on the first measurement result measured at the position that is the first measurement distance away and the second measurement result measured at the position that is the second measurement distance away. [Explanation of symbols]

[0079] C...central axis, D...measurement distance, D1...first measurement distance, D2...second measurement distance, R...radius, 10...improved soil quality control system, 11...rotating device, 13...rotating table, 21...measuring device, 22...laser measurement unit, 23...control unit, 24...distance detection unit, 31...sample, 32...container, 33...improved soil, 34...measurement area.

Claims

1. Continuously measuring the calcium content of the improved soil prepared by mixing the soil and the improvement material by X-ray fluorescence analysis while moving the improved soil; and evaluating the strength of the improved soil based on the measurement results.

2. In the quality control method of improved soil according to claim 1, A quality control method for improved soil, which comprises rotating the improved soil around a vertical central axis and continuously measuring the calcium content by X-ray fluorescence analysis at positions radially spaced from the center of rotation.

3. In the quality control method for improved soil according to claim 1 or 2, A quality control method for improved soil, which comprises rotating the improved soil around a vertical central axis and continuously measuring the calcium content at positions vertically spaced from the improved soil by X-ray fluorescence analysis.

4. In the quality control method of improved soil according to claim 3, Rotating the improved soil around a central axis along the vertical direction, continuously detecting a measurement distance from the improved soil in the vertical direction; and correcting the continuously measured calcium content based on the continuously detected measurement distance.

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