Compaction characteristic measurement method

Abstract

To more accurately evaluate a quality of a structure.SOLUTION: A compaction property measurement method for measuring compaction property of a soil material mixture 20 manufactured by mixing an uncleaned excavation soil material, cement, and water includes: a storage step of storing the mixed soil material mixture 20 in a container 22; a compaction step of compacting the soil material mixture 20 stored in the container 22 after a predetermined elapsed time of one hour or more has elapsed after manufacture of the soil material mixture 20; and a property measurement step of measuring compaction property of the soil material mixture 20 compacted in the container 22.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for measuring the compaction characteristics of a soil material mixture. [Background technology]

[0002] Patent Document 1 discloses a CSG method in which cement and water are added to and mixed with on-site materials (excavated soil material), which is then transported to a construction site, spread out using a bulldozer, and compacted using a vibrating roller to build a structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-168977 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a CSG method such as the invention described in Patent Document 1, it may take a relatively long time for the CSG to be compacted after it is manufactured. If the time until compaction is long, the cement may set and the compaction characteristics of the CSG, such as the degree of compaction, may decrease. Since the length of time until the CSG is compacted varies depending on the location where the CSG is spread, it is difficult to accurately evaluate the quality of the entire structure by only understanding the compaction characteristics of the CSG a specific amount of time has passed since its manufacture.

[0005] The present invention aims to more accurately evaluate the quality of a structure. [Means for solving the problem]

[0006] The present invention relates to a method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, the method including the steps of: storing the mixed soil material mixture in a container; and storing the soil material mixture stored in the container for at least one hour after the production of the soil material mixture. Pre-configured The method includes a compaction step of compacting the mixture after a predetermined time has elapsed, and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture in the container. The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, the method comprising: a container step of containerizing the mixed soil material mixture; a compaction step of compacting the soil material mixture contained in the container after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture in the container, in which, before one hour has elapsed since the production of the soil material mixture, a weaker compaction is performed by tamping with a tamping rod than the compaction performed after the elapse of the elapsed time. . The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, the method comprising: a storage step of storing the mixed soil material mixture in a container; a compaction step of compacting the soil material mixture stored in the container after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measurement step of measuring the compaction characteristics of the compacted soil material mixture in the container, in which a plurality of soil material mixtures to which different amounts of an admixture having the effect of delaying the setting reaction of cement have been added are stored in a plurality of containers set to the same elapsed time in the storage step, and the compaction characteristics of each of the compacted soil material mixtures are measured in the characteristic measurement step.

[0007] The present invention also provides a method for measuring the compaction characteristics of a soil material mixture produced by mixing excavated soil material having a mass fraction of soil passing through a sieve with a nominal size of 0.15 mm or more in accordance with at least JIS A 1204 "Soil Grain Size Testing Method", cement, and water, the method comprising the steps of: placing the mixed soil material mixture in a container; and storing the soil material mixture placed in the container for at least one hour after the production of the soil material mixture. Pre-configured The method includes a compaction step of compacting the mixture after a predetermined time has elapsed, and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture in the container. The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing excavated soil material having a mass fraction of more than 3% passing a sieve with a nominal size of 0.15 mm in accordance with at least JIS A 1204 "Testing methods for soil particle size", cement, and water, the method comprising the steps of: storing the mixed soil material mixture in a container; compacting the soil material mixture stored in the container after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and measuring the compaction characteristics of the compacted soil material mixture in the container, in which, before one hour has elapsed since the production of the soil material mixture, a weaker compaction is performed by tamping with a tamping rod than the compaction performed after the elapsed time. The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing excavated soil material having a mass fraction of more than 3% of soil passing a sieve with a nominal size of 0.15 mm in accordance with at least JIS A 1204 "Testing methods for soil particle size", cement, and water, the method comprising the steps of: storing the mixed soil material mixture in a container; compacting the soil material mixture stored in the container after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and measuring the compaction characteristics of the compacted soil material mixture in the container, in which a plurality of soil material mixtures to which different amounts of an admixture having an effect of retarding the setting reaction of cement have been added are respectively stored in a plurality of containers set to the same elapsed time in the storing step; and measuring the compaction characteristics of each of the compacted soil material mixtures in the measuring step.

[0008] The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, the method comprising the steps of: spreading the mixed soil material mixture; and subjecting the spread soil material mixture to a process of measuring the compaction characteristics of the soil material mixture for one hour or more after the production of the soil material mixture. Pre-configured The method includes a compaction step of compacting the mixture after a predetermined time has elapsed, and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture. The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, the method comprising: a spreading step of spreading the mixed soil material mixture; a compaction step of compacting the spread-leveled soil material mixture after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measurement step of measuring the compaction characteristics of the compacted soil material mixture, in which in the spreading step, a plurality of soil material mixtures to which different amounts of an admixture having the effect of delaying the setting reaction of cement have been added are spread level separately; in the compaction step, the plurality of soil material mixtures spread level separately are each compacted after the same elapsed time has elapsed; and in the characteristic measurement step, the compaction characteristics of the plurality of soil material mixtures spread level and compacted separately are each measured.

[0009] The present invention also relates to a method for measuring the compaction characteristics of a soil material mixture produced by mixing excavated soil material having a mass fraction of soil passing through a sieve with a nominal size of 0.15 mm or more in accordance with JIS A 1204 "Soil Grain Size Testing Method", cement, and water, the method comprising the steps of: spreading the mixed soil material mixture; and subjecting the spread soil material mixture to a process of measuring the compaction characteristics of the soil material mixture for at least one hour after the production of the soil material mixture. Pre-configured The method includes a compaction step of compacting the mixture after a predetermined time has elapsed, and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture. The present invention also provides a method for measuring compaction characteristics of a soil material mixture produced by mixing excavated soil material having a mass fraction of more than 3% passing a sieve with a nominal size of 0.15 mm in accordance with at least JIS A 1204 "Testing methods for soil particle size", cement, and water, the method comprising: a spreading step of spreading the mixed soil material mixture; a compaction step of compacting the spread-leveled soil material mixture after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture, in which in the spreading step, a plurality of soil material mixtures to which different amounts of an admixture having an effect of delaying the setting reaction of cement have been added are separately spread and leveled; in the compaction step, the plurality of soil material mixtures that have been separately spread and compacted are each compacted after the same elapsed time has elapsed; and in the characteristic measuring step, the compaction characteristics of the plurality of soil material mixtures that have been separately spread and compacted are each measured. Effect of the Invention

[0010] According to the present invention, the quality of a structure can be evaluated more accurately. [Brief description of the drawings]

[0011] [Figure 1] A longitudinal section of a trapezoidal CSG dam. [Diagram 2] This is a front view of the trapezoidal CSG dam seen from the upstream side. [Diagram 3] FIG. 2 is a cross-sectional view showing a cross section of a CSG layer that constitutes a trapezoidal CSG dam. [Figure 4] FIG. 2 is a diagram showing a chronological order of steps for preparing a specimen in the method for measuring compaction characteristics of a soil material mixture according to the first embodiment of the present invention. [Diagram 5] 5 is a diagram showing, in chronological order, the steps of producing a specimen structure in the method for measuring compaction characteristics of a soil material mixture according to the second embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a method for measuring compaction characteristics of a soil material mixture according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a structure to be evaluated for quality by the method for measuring compaction characteristics is a trapezoidal CSG dam 100 constructed by the CSG (Cemented Sand and Gravel) construction method.

[0013] First, the trapezoidal CSG dam 100 will be described with reference to Figures 1 and 2. Figure 1 is a vertical cross-sectional view (upstream / downstream cross-sectional view) of the trapezoidal CSG dam 100, and Figure 2 is a front view of the trapezoidal CSG dam 100 as viewed from the upstream side (as viewed from the left side in Figure 1).

[0014] As shown in Fig. 1, the trapezoidal CSG dam 100 is a trapezoidal dam with a generally trapezoidal cross section in the upstream and downstream directions, and is constructed by covering the surface of a dam body made of CSG piled up in a trapezoid shape with protective concrete. Also, as shown in Fig. 2, the trapezoidal CSG dam 100 has left and right side surfaces anchored to bedrock 102, 103, respectively. For ease of explanation, the left and right direction shown in Fig. 1, i.e., the direction in which the river flows, is referred to as the upstream and downstream direction of the trapezoidal CSG dam 100.

[0015] The CSG, which is the material for the dam body of the trapezoidal CSG dam 100, is a soil material mixture (cement-based mixture) produced by mixing water and cement with excavated soil material (locally generated material) consisting of sand and gravel, rock blocks, etc., which are readily available around the construction site. The aggregate contains coarse aggregate such as crushed stone and coarse gravel with a particle size of about 80 mm, which is larger than the maximum particle size (40 mm) of aggregate for general ready-mixed concrete. Although the excavated soil material may be processed to remove oversized pieces or to be crushed, classification, particle size adjustment, and washing are not generally performed. In other words, CSG, which is mainly made of excavated soil material, can be continuously produced by equipment simpler than that for producing concrete, and therefore, when constructing the trapezoidal CSG dam 100, equipment such as aggregate production equipment required for the construction of general concrete dams is not required. Cement can be Portland cement, mixed cement, special cement, etc., but Portland cement or mixed cement (blast furnace cement, fly ash cement, etc.) is used for CSG and CSG construction methods. In particular, moderate heat Portland cement, blast furnace cement (Type B), Portland cement mixed with fly ash, and moderate heat Portland cement mixed with fly ash cement can be used.

[0016] The trapezoidal CSG dam 100 is constructed by stacking one lift of CSG layers 10 from bottom to top, each of which is formed by pouring the CSG, which is a soil material mixture as described above. The height of each of the CSG layers 10, i.e., the lift height h, is about 75 cm to 100 cm.

[0017] 1 and 2 show a trapezoidal CSG dam 100 consisting of six CSG layers 10 for simplicity. The CSG layers 10 formed at the top are shorter in length in the upstream and downstream directions. For this reason, stepped portions are formed on the upstream and downstream side surfaces of the trapezoidal CSG dam 100.

[0018] The construction of each CSG layer 10 will now be described with reference to Figure 3. Figure 3 shows a cross section of a CSG layer 10 under construction.

[0019] The CSG layer 10 is constructed by spreading CSG thinly and widely, a so-called thin layer spreading method, and as shown in Figure 3, a structure is constructed by hardening multiple layers 11, 12, and 13 formed by overlapping CSG layers.

[0020] Specifically, first, the CSG is transported to the construction site by a transport machine such as a dump truck, conveyor, or crane, and then the transported CSG is spread and compacted by a leveling machine such as a bulldozer to form the bottom layer, the first layer 11.

[0021] Next, CSG is transported by a transport machine onto the top surface of the spread first layer 11, and the transported CSG is spread and compacted by a spreading machine to form a second layer 12 of the intermediate layer.

[0022] Furthermore, CSG is transported onto the top surface of the spread second layer 12 by a transport machine, and the transported CSG is spread and compacted by a spreading machine to form the uppermost third layer 13.

[0023] After the third layer 13 is formed, as shown in Fig. 3, the surface of the third layer 13 is compacted by a compaction machine (rolling machine) such as a vibrating roller 16, and the first layer 11, the second layer 12, and the third layer 13 are compacted. In other words, at least the uppermost layer of the three layers 11, 12, and 13 constituting the CSG layer 10 is spread and leveled by a leveling machine, and then compacted and condensed by the compaction machine. Note that the first layer 11 and the second layer 12 may also be spread and leveled by a leveling machine, and then compacted and condensed by the compaction machine, in the same manner as the third layer 13.

[0024] The heights of the layers 11, 12, and 13 thus formed (the first height h1 which is the height of the first layer 11, the second height h2 which is the height of the second layer 12, and the third height h3 which is the height of the third layer 13) are set to about 10 cm to 30 cm. However, the heights of the layers 11, 12, and 13 are not strictly the same, and differences arise depending on the state of spreading and compaction.

[0025] By repeating this process and stacking the CSG layers 10 from bottom to top, the trapezoidal CSG dam 100 is constructed as a structure.

[0026] Here, in the above-mentioned CSG method, it may take a relatively long time (for example, up to about 6 hours) from the production of CSG (soil material mixture) by adding and mixing cement and water to excavated soil material (on-site generated material) to compaction (rolling compaction). If it takes a long time to compact, the cement may have set to a certain extent before compaction begins, which may reduce the compaction characteristics of the CSG, such as the degree of compaction. The reduction in compaction characteristics affects the density and strength of the structure, leading to a decrease in density and strength, and ultimately reducing the quality of the CSG as a structure.

[0027] The length of time until the CSG is compacted varies depending on the location where the CSG is spread. For example, as described above, when the CSG layer 10 is composed of multiple layers, the lowest first layer 11 is finally compacted together with the second layer 12 and the third layer 13 by a compaction machine (roller) after the second layer 12 and the third layer 13 are spread. For this reason, the time from when the first layer 11 is spread to when it is compacted is longer than that of the second layer 12 and the third layer 13. Similarly, the time from when the second layer 12 is spread to when it is compacted is longer than that of the third layer 13.

[0028] In this way, the length of time that the CSG is left after it is spread and before compaction begins varies depending on the location in the structure where the CSG is spread, etc. In other words, the length of time from when the CSG is produced, i.e., when the excavated soil material is mixed with cement and water, to when compaction by a compaction machine (roller) begins varies depending on where the CSG is spread, for example, on which of layers 11-13 the CSG is spread.

[0029] Since the time that elapses between when CSG is manufactured and when compaction begins affects the quality of the CSG as a structure that is constructed by compacting the CSG, understanding the compaction characteristics after a specified time has elapsed is important for maintaining and improving quality.

[0030] Therefore, in the method for measuring the compaction characteristics of a soil material mixture according to an embodiment of the present invention, the CSG, which is the soil material mixture used to construct a structure, is compacted under temporal and physical conditions that reflect actual construction, and the compaction characteristics of the compacted soil material mixture are measured, making it possible to grasp the compaction characteristics of the soil material mixture.

[0031] First Embodiment Hereinafter, a method for measuring compaction characteristics of a soil material mixture (CSG) according to a first embodiment of the present invention will be described with reference to Fig. 4. In the method for measuring compaction characteristics of a soil material mixture according to the first embodiment, a specimen is prepared using CSG used in the construction of a structure, and the compaction characteristics of the prepared specimen are measured. Fig. 4 (A) to (C) are diagrams showing the preparation process of a specimen whose compaction characteristics are to be measured in chronological order.

[0032] First, with reference to FIG. 4, the process of preparing a specimen for measuring compaction characteristics will be described.

[0033] In preparing the test specimen, excavated soil material (on-site generated material) is mixed with water and cement using a mixer such as a pot mixer to produce a soil material mixture 20 (CSG) (production process). The produced soil material mixture 20 is then stored in a cylindrical container 22 in the storage process shown in FIG. 4(A).

[0034] The excavated soil material used in producing the soil material mixture 20 is the same material as that used to construct the structure, and is unwashed locally generated material that is not washed, and the mass fraction of the material passing through a sieve with a nominal size of 0.15 mm according to JIS A 1204:2009 "Soil Grain Size Testing Method" is more than 3%, preferably more than 5%, of the entire excavated soil material. In addition, the excavated soil material is adjusted to a maximum particle size (80 mm) or less by removing oversize particles as necessary. Thus, since the soil material mixture 20 contained in the container 22 includes excavated soil material with a relatively large particle size of about 80 mm, the inner diameter of the container 22 is set to a size of at least three times the maximum particle size, preferably about 300 mm.

[0035] 4(B), the soil material mixture 20 contained in the container 22 is tamped with a tamping rod (not shown) and then further compacted for a predetermined time, for example, 5 to 10 seconds, by the electric hammer 24. The soil material mixture 20 may be compacted by a vibration tamper instead of the electric hammer 24.

[0036] This primary compaction process is carried out in order to reproduce the state in which the CSG, which is still in a relatively fluid state, is compacted to a certain extent by a leveling machine such as a bulldozer when the CSG is leveled by the leveling machine in actual construction. For this reason, the primary compaction process is carried out in accordance with the timing of leveling in actual construction, for example, within one hour after the soil material mixture 20 is produced.

[0037] In addition, in the primary compaction process, the number of times the soil material mixture 20 is struck with the ram and the time for compacting the soil material mixture 20 with the electric hammer 24 are preset so that the density of the soil material mixture 20 after the primary compaction process is completed is equivalent to the density of the CSG after it has been spread by a spreading machine in actual construction.

[0038] In addition, the number of times the thrust rod is used and the time for compaction by the electric hammer 24 may be set so that the impact energy imparted to the soil material mixture 20 is equivalent to the compaction energy imparted to the CSG by the leveling machine in actual construction.

[0039] Once the primary compaction step is completed, a secondary compaction step is performed as shown in FIG. 4(C) and described below. However, before the secondary compaction step is performed, the soil material mixture 20 is left to stand for a predetermined period of time in a standing step.

[0040] The leaving process is carried out to reproduce the condition that occurs during actual construction, when the CSG is left after being spread out by a spreading machine such as a bulldozer and before being compacted by a compaction machine (compaction machine) such as a vibrating roller.

[0041] Here, in actual construction, the time that CSG is left unattended is a maximum of about six hours, whereas the time from when CSG is manufactured to when spreading is completed is generally within one hour, which is shorter than the time that it is left unattended. Therefore, in actual construction, the time that CSG is left unattended until it is compacted by a compaction machine can be said to be almost equal to the time from when CSG is manufactured to when it is compacted by a compaction machine.

[0042] Furthermore, since the cement setting reaction begins when CSG is produced, i.e., when cement and water are mixed with the excavated soil material, it can be said that the change in the compaction characteristics of CSG over time begins from this time.

[0043] Furthermore, in actual construction, the time for which the CSG is left standing varies depending on the location where the CSG is laid, etc., as described above.

[0044] Taking these factors into consideration, in this embodiment, the time that elapses from the production of the soil material mixture 20 until the start of the secondary compaction process is set to a time equivalent to the time that the CSG is left after being spread and leveled in an actual construction until compaction is performed by a compaction machine, and this time is set in advance as the elapsed time for each container 22. Furthermore, since a structure is constructed by performing final compaction, the time until compaction is completed is closely related to the quality of the CSG as a structure.

[0045] This elapsed time is set to a different length for each container 22, and specifically, is set at 1-2 hour intervals between 1 hour and 8 hours after the production of the soil material mixture 20 so as to reliably include the time during which the CSG is left in actual construction. Measurement of the elapsed time begins from the time when the excavated soil material is mixed with cement and water in the production process of the soil material mixture 20.

[0046] The elapsed time that is set is not limited to this, and may be set to a time that exceeds 8 hours after the production of the soil material mixture 20, or may be set to the time at which the secondary compaction process is started immediately after the completion of the primary compaction process, i.e., the time that assumes that the CSG is left unattended for 0 hours.

[0047] Also, instead of the elapsed time, the time that elapses from the completion of the primary compaction process to the start of the secondary compaction process may be set as the time that the CSG is left standing in the actual construction, and this time may be set as the standing time for each container 22. In this case, the measurement of the standing time starts at the time that the primary compaction process is completed.

[0048] When the leaving step is completed, that is, when the elapsed time preset for each container 22 has elapsed, in the secondary compaction step shown in FIG. 4(C), the soil material mixture 20 contained in the container 22 is compacted by the electric hammer 24 for a predetermined time, for example, 50 to 60 seconds. In the secondary compaction step, the time required for compaction is about 90 to 120 seconds at most. Since the compaction time of the secondary compaction is significantly longer than that of the primary compaction, the compaction energy applied to the soil material mixture 20 via the electric hammer 24 is large. Therefore, it can be said that the compaction load of the secondary compaction is larger than that of the primary compaction, and the compaction is stronger. In other words, it can be said that the primary compaction is weaker than the secondary compaction. In addition, since the time required for the compaction work is about 2 minutes at most, in the compaction step performed after a predetermined time of one hour or more has elapsed, the time when the compaction started can be said to be the time when the compaction is completed.

[0049] This secondary compaction process is performed to reproduce the compacted state of the CSG in actual construction by compacting it with a compaction machine (roller) such as a vibrating roller. Therefore, the time for compacting the soil material mixture 20 with the electric hammer 24 in the secondary compaction process is set in advance so that the density of the soil material mixture 20 after the secondary compaction process is equivalent to the density of the CSG after it is compacted by the compaction machine in actual construction.

[0050] In addition, in the secondary compaction process, the time for compacting the soil material mixture 20 by the electric hammer 24 may be set so that the impact energy imparted to the soil material mixture 20 is equivalent to the compaction energy imparted to the CSG by the compaction machine in actual construction.

[0051] As described above, the secondary compaction process assumes a state in which the CSG is compacted by a compaction machine (roller) such as a vibrating roller in actual construction, whereas the primary compaction process assumes a state in which the CSG is eventually compacted by a leveling machine such as a bulldozer when it is leveled by the leveling machine, but in actual construction, the degree of compaction by the leveling machine is much smaller than the degree of compaction by a compaction machine such as a vibrating roller. Therefore, in order to simplify the process of preparing the test specimen, it is possible to skip the primary compaction process and only perform the secondary compaction process.

[0052] After the secondary compaction process is completed, the soil material mixture 20 in each container 22 is cured for a predetermined period of time under predetermined curing conditions in a curing process. After a sufficient curing period (e.g., 2 to 3 days) has passed, the soil material mixture 20 that has hardened to a certain extent is taken out of the container 22 as a test specimen.

[0053] In the subsequent property measuring step, the density of the cylindrical specimen removed from the container 22 is measured as the compaction property of the soil material mixture 20.

[0054] Specifically, the volume and weight of the specimen are measured, and the density is calculated from the measured volume and weight. If there is a risk that the specimen will collapse when measuring the volume, the density of the specimen is measured using an RI density meter, which irradiates the specimen with gamma rays and calculates the density of the specimen from the transmission attenuation rate.

[0055] The density is calculated for each test specimen, that is, for each of the soil material mixtures 20 that are contained in the multiple containers 22 and compacted with different elapsed times set. Therefore, it is possible to understand how the compaction characteristics of the soil material mixture 20 change due to differences in the elapsed time (1 hour to 6 hours).

[0056] As the compaction characteristics of the soil material mixture 20, the water content or compressive strength of the specimen may be measured instead of or in addition to the density of the specimen.

[0057] In this way, by grasping the compaction characteristics of the soil material mixture 20 according to the elapsed time, even if the time left after spreading by a spreading machine and before compacting by a compaction machine varies depending on the location where the CSG is spread, such as in the trapezoidal CSG dam 100, if the time left for each location where the CSG is spread is recorded, it is possible to obtain the compaction characteristics corresponding to the time left from the results measured by the above-mentioned compaction characteristic measuring method. Therefore, even for a relatively large structure, the compaction characteristics of each part are clearly defined, and the quality of the entire structure can be accurately evaluated.

[0058] Instead of the time that the CSG is left standing, the time that has elapsed since the CSG was produced until the CSG was compacted may be recorded for each location where the CSG was spread. In this case, the recorded elapsed time corresponds to the elapsed time set for each container 22, so that the compaction characteristics corresponding to the recorded elapsed time can be obtained from the results measured by the above-mentioned compaction characteristic measuring method. Therefore, in this case as well, the compaction characteristics of each part of a relatively large structure become clear, and the quality of the entire structure can be accurately evaluated.

[0059] According to the above-described first embodiment, the following advantageous effects are achieved.

[0060] In the above-mentioned compaction characteristic measuring method, the compaction characteristics of the soil material mixture 20 are measured through a storage step of storing the mixed soil material mixture 20 in a container 22, a compaction step of compacting the soil material mixture 20 stored in the container 22 after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture 20, and a characteristic measuring step of measuring the compaction characteristics of the compacted soil material mixture 20 in the container 22.

[0061] By grasping the compaction characteristics of the soil material mixture 20 according to a predetermined elapsed time in this way, even if the time left before compaction varies depending on the location where the CSG is spread, such as in the trapezoidal CSG dam 100, if the time left for each location where the CSG is spread is recorded, it is possible to obtain the compaction characteristics corresponding to the time left from the results measured by the above-mentioned compaction characteristic measurement method. Therefore, even for a relatively large structure, the compaction characteristics of each part are clearly known, and the quality of the entire structure can be accurately evaluated.

[0062] In the above-mentioned compaction characteristic measuring method, the conditions for compacting the soil material mixture 20 contained in the container 22 are set assuming spreading and compaction in actual construction. By setting the conditions for compacting the soil material mixture 20 in such a way that the compacted state due to spreading and compaction in actual construction can be reproduced, it becomes possible to grasp the compaction characteristics in a state close to that in actual construction, and as a result, it is possible to grasp the compaction characteristics of the entire structure with greater accuracy.

[0063] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the first embodiment above, or to combine the configurations described in the different modified examples below.

[0064] The soil material mixture 20 of the first embodiment may be added with an admixture having an effect of delaying the setting reaction of cement. The admixture is a so-called setting retarder such as "Floric T (Floric is a registered trademark)" (manufactured by Floric Co., Ltd.), and for example, the difference in the setting time of the cement according to JIS A 1147:2019 "Testing method for setting time of concrete" is about +95 minutes at the start time and about +100 minutes at the end time. The admixture may be any admixture that is +0 minutes or more at the start time and +15 minutes or more at the end time, according to JIS A 1147:2019 "Testing method for setting time of concrete".

[0065] Specifically, in the storing step, the soil material mixture 20 with different amounts of admixture added is stored in a plurality of containers 22 set to the same elapsed time, and in the characteristic measuring step, the compaction characteristics of the compacted soil material mixture 20 are measured. By changing the amount of admixture added to the soil material mixture 20 in this way, the effect of the admixture on the compaction characteristics can be understood.

[0066] Furthermore, by storing soil material mixtures 20 containing the same amount of admixture in multiple containers 22 each having a different elapsed time set, and measuring the compaction characteristics of the compacted soil material mixtures 20, it is possible to understand how the compaction characteristics of the soil material mixtures 20 to which admixtures have been added change with different elapsed times.

[0067] Furthermore, by comprehensively understanding the changes in the compaction characteristics of the soil material mixture 20 due to differences in the elapsed time and the amount of admixture added, even if the amount of admixture added to the CSG differs in each part of the structure, the corresponding compaction characteristics of the CSG can be determined from the results measured using the above-mentioned compaction characteristic measurement method, as long as the amount of admixture added in each part and the time the CSG was left standing or the time elapsed from the production of the CSG to compaction are known.

[0068] <Second embodiment> Next, a method for measuring compaction characteristics of a soil material mixture (CSG) according to a second embodiment of the present invention will be described with reference to Fig. 5. In the method for measuring compaction characteristics of a soil material mixture according to the second embodiment, a material equivalent to CSG used in the construction of a structure is spread and compacted using equipment equivalent to that used in actual construction, and the compaction characteristics of the obtained test structure are measured. Fig. 5 (A) to (B) are diagrams showing the chronological order of the production process of the test structure whose compaction characteristics are to be measured.

[0069] First, with reference to FIG. 5, the process of preparing a test structure whose compaction characteristics are to be measured will be described.

[0070] In preparing the test structure, excavated soil material (on-site generated material) is mixed with water and cement using a mixer such as a pot mixer to produce a soil material mixture 20 (CSG) (production process). In the spreading process, the produced soil material mixture 20 is spread evenly in a predetermined section divided on the test yard as shown in Fig. 5(A).

[0071] The soil material mixture 20 is spread by a spreading machine such as a bulldozer 26 in the same manner as in actual construction, and the soil material mixture 20 is spread and compacted to a certain extent by the spreading machine. The spreading process is carried out within one hour after the soil material mixture 20 is produced, in accordance with the timing of spreading in actual construction. Spreading by a spreading machine such as a bulldozer also has a compaction effect, but compared to compaction by a compaction machine (roller) such as a vibrating roller, the compaction energy imparted to the soil material mixture 20 is small, so it can be said to be weak compaction.

[0072] After the leveling step is completed, the compaction step described below is carried out. Before the compaction step is carried out, the soil material mixture 20 is left to stand for a predetermined period of time in a leaving step.

[0073] The leaving process is carried out to reproduce the condition that occurs during actual construction, when the CSG is left after being spread out by a spreading machine such as a bulldozer and before being compacted by a compaction machine (compaction machine) such as a vibrating roller.

[0074] Here, in actual construction, the time that CSG is left unattended is a maximum of about six hours, whereas the time from when CSG is manufactured to when spreading is completed is generally within one hour, which is shorter than the time that it is left unattended. Therefore, in actual construction, the time that CSG is left unattended until it is compacted by a compaction machine can be said to be almost equal to the time from when CSG is manufactured to when it is compacted by a compaction machine.

[0075] In addition, since the cement setting reaction begins when CSG is produced, i.e., when cement and water are mixed with the excavated soil material, it can be said that the change in the compaction characteristics of CSG over time begins from this time.

[0076] Furthermore, in actual construction, the time for which the CSG is left standing varies depending on the location where the CSG is laid, etc., as described above.

[0077] Taking these into consideration, in this embodiment, the time that elapses from when the soil material mixture 20 is produced until the compaction process by the compaction machine is started is set to the time that corresponds to the time that the CSG is left in actual construction, and this time is set in advance as the elapsed time for each section in which the soil material mixture 20 is spread. Note that, since the time required for compaction work by a compaction machine (roller) such as a vibrating roller is about 5 minutes, in the compaction process that is performed after a predetermined time of 1 hour or more has elapsed, the time that compaction starts can be said to be the time that compaction is generally completed.

[0078] This elapsed time is set to a different length for each section in which the soil material mixture 20 is spread, and specifically, is set at 1-2 hour intervals between 1 hour and 8 hours after the production of the soil material mixture 20 so as to reliably include the time during which the CSG is left in the actual construction. Measurement of the elapsed time begins from the time when the excavated soil material is mixed with cement and water in the production process of the soil material mixture 20.

[0079] The elapsed time that is set is not limited to this, and may be set to a time that exceeds 8 hours after the production of the soil material mixture 20, or may be set to the time when the compaction process begins immediately after the spreading process is completed, that is, the time that assumes that the CSG is left unattended for 0 hours.

[0080] Alternatively, instead of the elapsed time, the time that elapses from the completion of the spreading process to the start of the compaction process may be set as the time that the CSG is left in the actual construction, and this time may be set as the left time for each section. In this case, the measurement of the left time starts at the time that the spreading process is completed.

[0081] When the leaving process is completed, that is, when the predetermined time for each section has elapsed, in the compaction process, as shown in FIG. 5(B), the soil material mixture 20 is compacted by a compaction machine (roller) such as a vibrating roller 28, as in actual construction.

[0082] After the compaction process is completed, the soil material mixture 20 in each section is cured for a predetermined period of time under predetermined curing conditions in the curing process. After a sufficient curing period (e.g., 2 to 3 days) has passed, the soil material mixture 20 hardens to a certain extent and becomes a test structure.

[0083] In a subsequent property measuring step, the density of the test structure is measured as a compaction property of the soil material mixture 20 .

[0084] Specifically, a cylindrical core (specimen) is first extracted from the test structure by a coring machine. The volume and weight of the extracted core are then measured, and the density is calculated from the measured volume and weight. If there is a risk that the core will collapse when measuring the volume, the density of the core is measured by an RI density meter, which irradiates the core with gamma rays and calculates the density of the core from the transmission attenuation rate.

[0085] The density of the test structure may be measured by installing a scattering type RI densitometer on the top surface of the test structure, without taking a core.

[0086] A scattering type RI density meter is installed on the surface of a measurement object, emits gamma rays toward the inside of the measurement object, and detects the gamma rays scattered from inside the measurement object toward the surface of the measurement object. Since gamma rays are more likely to disappear the higher the density, it is possible to calculate the density of the test structure by measuring the percentage of the gamma rays that are scattered toward the surface of the test structure compared to the amount of gamma rays emitted into the test structure.

[0087] The density is calculated for each test structure, that is, for each of the soil material mixtures 20 that are spread evenly and compacted in a plurality of sections where the elapsed time is set to be different from each other. Therefore, it is possible to understand how the compaction characteristics of the soil material mixture 20 change due to the difference in the elapsed time (1 hour to 6 hours).

[0088] As the compaction characteristics of the soil material mixture 20, the water content of the test structure or the compressive strength of the test structure may be measured instead of or in addition to the density of the test structure.

[0089] In this way, by grasping the compaction characteristics of the soil material mixture 20 according to the elapsed time, even if the time left after spreading by a spreading machine and before compacting by a compaction machine varies depending on the location where the CSG is spread, such as in the trapezoidal CSG dam 100, if the time left for each location where the CSG is spread is recorded, it is possible to obtain the compaction characteristics corresponding to the time left from the results measured by the above-mentioned compaction characteristic measuring method. Therefore, even for a relatively large structure, the compaction characteristics of each part are clearly defined, and the quality of the entire structure can be accurately evaluated.

[0090] Instead of the time that the CSG is left standing, the time that has elapsed since the CSG was produced until the CSG was compacted may be recorded for each location where the CSG is spread. In this case, the recorded elapsed time corresponds to the elapsed time set for each section, so that the compaction characteristics corresponding to the recorded elapsed time can be obtained from the results measured by the above-mentioned compaction characteristic measurement method. Therefore, in this case as well, the compaction characteristics of each part of a relatively large structure become clear, and the quality of the entire structure can be accurately evaluated.

[0091] According to the above-described second embodiment, the following advantageous effects are achieved.

[0092] In the above-mentioned compaction characteristic measuring method, the compaction characteristics of the soil material mixture 20 are measured through a spreading process in which the mixed soil material mixture 20 is spread evenly, a compaction process in which the spread and leveled soil material mixture 20 is compacted after a predetermined time, which is at least one hour, has elapsed since the production of the soil material mixture 20, and a characteristic measuring process in which the compaction characteristics of the compacted soil material mixture 20 are measured.

[0093] By grasping the compaction characteristics of the soil material mixture 20 according to a predetermined elapsed time in this way, even if the time left before compaction varies depending on the location where the CSG is spread, such as in the trapezoidal CSG dam 100, if the time left for each location where the CSG is spread is recorded, it is possible to obtain the compaction characteristics corresponding to the time left from the results measured by the above-mentioned compaction characteristic measurement method. Therefore, even for a relatively large structure, the compaction characteristics of each part are clearly known, and the quality of the entire structure can be accurately evaluated.

[0094] In the above-mentioned compaction characteristic measuring method, the soil material mixture 20 is spread and compacted in the test yard in the same manner as in actual construction. By spreading and compacting the soil material mixture 20 in the same manner as in actual construction, it becomes possible to grasp the compaction characteristics in a state close to that of actual construction, and as a result, it is possible to grasp the compaction characteristics of the entire structure with greater accuracy.

[0095] In addition, the following modified examples are also within the scope of the present invention, and it is also possible to combine the configuration shown in the modified example with the configuration described in the second embodiment above, or to combine the configurations described in the different modified examples below.

[0096] The soil material mixture 20 of the second embodiment may be added with an admixture having an effect of delaying the setting reaction of cement. The admixture is a so-called setting retarder such as "Floric T (Floric is a registered trademark)" (manufactured by Floric Co., Ltd.), and for example, the difference in the setting time of the cement according to JIS A 1147:2019 "Testing method for setting time of concrete" is about +95 minutes at the start time and about +100 minutes at the end time. The admixture may be any admixture that is +0 minutes or more at the start time and +15 minutes or more at the end time, according to JIS A 1147:2019 "Testing method for setting time of concrete".

[0097] Specifically, in the spreading step, soil material mixture 20 with different amounts of admixture added is spread in a plurality of sections set to have the same elapsed time, and in the characteristic measuring step, the compaction characteristics of the compacted soil material mixture 20 are measured. By changing the amount of admixture added to the soil material mixture 20 in this way, the effect of the admixture on the compaction characteristics can be understood.

[0098] Furthermore, by spreading the soil material mixture 20 containing the same amount of admixture in multiple sections each having a different elapsed time, and measuring the compaction characteristics of the compacted soil material mixture 20, it is possible to understand how the compaction characteristics of the soil material mixture 20 containing added admixture change with the difference in elapsed time.

[0099] Furthermore, by comprehensively understanding the changes in the compaction characteristics of the soil material mixture 20 due to differences in the elapsed time and the amount of admixture added, even if the amount of admixture added to the CSG differs in each part of the structure, the corresponding compaction characteristics of the CSG can be determined from the results measured using the above-mentioned compaction characteristic measurement method, as long as the amount of admixture added in each part and the time the CSG was left standing or the time elapsed from the production of the CSG to compaction are known.

[0100] In the second embodiment, the compaction characteristics of the soil material mixture 20 that is spread and compacted in the test yard are measured. Alternatively, the compaction characteristics may be measured in a structure constructed from CSG that has been subjected to a spreading process and compacted after a predetermined time has elapsed, such as the trapezoidal CSG dam 100, which is an actually constructed structure.

[0101] Specifically, in this case, cores are taken from at least three portions: a portion of the trapezoidal CSG dam 100 where the CSG has been left for the shortest time (for example, the third layer 13, which was left for the shortest time among the multiple CSG layers 10); a portion of the trapezoidal CSG dam 100 where the CSG has been left for the longest time (for example, the first layer 11, which was left for the longest time among the multiple CSG layers 10); and a portion that can be interpolated between these, and the density of the taken cores is measured.

[0102] In this way, by measuring the density of cores taken from multiple parts of the trapezoidal CSG dam 100 where the CSG has been left for different periods of time, it is possible to understand how the compaction characteristics of the CSG in the trapezoidal CSG dam 100 change depending on the time that has passed since the CSG was manufactured and compacted.

[0103] Furthermore, by comprehensively grasping the compaction characteristics of the CSG over time, it becomes possible to easily estimate the compaction characteristics of each part of even a relatively large structure such as the trapezoidal CSG dam 100, thereby enabling an accurate evaluation of the quality of the entire structure.

[0104] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0105] For example, in the above embodiment, the structure to be evaluated for quality by the compaction characteristic measuring method is described as the trapezoidal CSG dam 100, but the structure to be evaluated is not limited to this and may be, for example, a levee such as a sabo dam or a seawall. Also, as long as it has a structure constructed by the CSG method, it is not limited to structures that constitute levee bodies such as dams, and may be any structure. [Explanation of symbols]

[0106] 10...CSG layer 16... Vibration roller (roller) 20...Earth material mixture 22...container 24. Electric hammer 26 Bulldozer (leveling machine) 28... Vibration roller (roller) 100··· Trapezoidal CSG dam (structure)

Claims

1. A method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, comprising the steps of: A step of containing the mixed soil material mixture in a container; A compaction process of compacting the soil material mixture contained in the container after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and measuring compaction characteristics of the compacted soil material mixture in the container. Methods for measuring compaction characteristics.

2. A method for measuring compaction characteristics of a soil material mixture produced by mixing an excavated soil material having a mass fraction of soil passing through a sieve nominal size of 0.15 mm or more in accordance with JIS A 1204 "Soil Grain Size Test Method", cement, and water, comprising: A step of containing the mixed soil material mixture in a container; A compaction process of compacting the soil material mixture contained in the container after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and measuring compaction characteristics of the compacted soil material mixture in the container. Methods for measuring compaction characteristics.

3. In the storing step, the mixed soil material mixture is stored in a plurality of containers each having a different elapsed time set therein, In the characteristic measuring step, compaction characteristics of the compacted soil material mixtures in the plurality of containers are measured, The method for measuring compaction characteristics according to claim 1 or 2.

4. The soil material mixture is added with an admixture having an effect of delaying the setting reaction of the cement, In the storage step, the soil material mixture having the same elapsed time setting but different amounts of the admixture, or the soil material mixture having the same amount of the admixture added but different elapsed time settings, is stored in a plurality of containers, In the characteristic measuring step, the compaction characteristics of the compacted soil material mixture in each of the multiple containers are measured. The method for measuring compaction characteristics according to claim 1 or 2.

5. A method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, comprising the steps of: A step of containing the mixed soil material mixture in a container; A compaction process of compacting the soil material mixture contained in the container after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and measuring compaction characteristics of the compacted soil material mixture in the container; In the compaction step, before one hour has elapsed since the soil material mixture was produced, a weaker compaction is performed by tamping with a tamping rod than the compaction performed after the elapse of the elapsed time. Methods for measuring compaction characteristics.

6. A method for measuring compaction characteristics of a soil material mixture produced by mixing an excavated soil material having a mass fraction of soil passing through a sieve nominal size of 0.15 mm or more in accordance with JIS A 1204 "Soil Grain Size Test Method", cement, and water, comprising: A step of containing the mixed soil material mixture in a container; A compaction process of compacting the soil material mixture contained in the container after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and measuring compaction characteristics of the compacted soil material mixture in the container; In the compaction step, before one hour has elapsed since the soil material mixture was produced, a weaker compaction is performed by tamping with a tamping rod than the compaction performed after the elapse of the elapsed time. Methods for measuring compaction characteristics.

7. A method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, comprising the steps of: A step of containing the mixed soil material mixture in a container; A compaction process of compacting the soil material mixture contained in the container after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and measuring compaction characteristics of the compacted soil material mixture in the container; In the storing step, a plurality of the soil material mixtures to which different amounts of an admixture having an effect of delaying the setting reaction of the cement are added are respectively stored in a plurality of containers in which the elapsed time is set to the same length, In the characteristic measuring step, the compaction characteristics of each of the compacted soil material mixtures are measured. Methods for measuring compaction characteristics.

8. A method for measuring compaction characteristics of a soil material mixture produced by mixing an excavated soil material having a mass fraction of soil passing through a sieve nominal size of 0.15 mm or more in accordance with JIS A 1204 "Soil Grain Size Test Method", cement, and water, comprising: A step of containing the mixed soil material mixture in a container; A compaction process of compacting the soil material mixture contained in the container after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and measuring compaction characteristics of the compacted soil material mixture in the container; In the storing step, a plurality of the soil material mixtures to which different amounts of an admixture having an effect of delaying the setting reaction of the cement are added are respectively stored in a plurality of containers in which the elapsed time is set to the same length, In the characteristic measuring step, the compaction characteristics of each of the compacted soil material mixtures are measured. Methods for measuring compaction characteristics.

9. A method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, comprising the steps of: A spreading step of spreading the mixed soil material mixture; A compaction process of compacting the spread soil material mixture after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measuring step of measuring compaction characteristics of the compacted soil material mixture. Methods for measuring compaction characteristics.

10. A method for measuring compaction characteristics of a soil material mixture produced by mixing an excavated soil material having a mass fraction of soil passing through a sieve nominal size of 0.15 mm or more in accordance with JIS A 1204 "Soil Grain Size Test Method", cement, and water, comprising: A spreading step of spreading the mixed soil material mixture; A compaction process of compacting the spread soil material mixture after a predetermined elapsed time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measuring step of measuring compaction characteristics of the compacted soil material mixture. Methods for measuring compaction characteristics.

11. In the compaction step, the plurality of soil material mixtures that have been spread separately are compacted after the elapse of different elapsed times, In the characteristic measuring step, the characteristics of the plurality of soil material mixtures that have been separately spread and compacted are measured, The method for measuring compaction characteristics according to claim 9 or 10.

12. The soil material mixture is added with an admixture having an effect of delaying the setting reaction of the cement, In the spreading step, the soil material mixture having different amounts of the admixture added is spread on each of the sections in which the elapsed time is set to the same length, or the soil material mixture having the same amount of the admixture added is spread on each of the sections in which the elapsed time is set to different lengths, In the characteristic measuring step, compaction characteristics of the compacted soil material mixture in each of the multiple sections are measured. The method for measuring compaction characteristics according to claim 9 or 10.

13. A method for measuring compaction characteristics of a soil material mixture produced by mixing at least unwashed excavated soil material, cement, and water, comprising the steps of: A spreading step of spreading the mixed soil material mixture; A compaction process of compacting the spread soil material mixture after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measuring step of measuring compaction characteristics of the compacted soil material mixture, In the spreading step, a plurality of the soil material mixtures to which different amounts of admixtures having an effect of delaying the setting reaction of the cement are added are spread separately, In the compaction step, the plurality of soil material mixtures that have been spread separately are each compacted after the same elapsed time has elapsed, In the characteristic measuring step, the compaction characteristics of the plurality of soil material mixtures that have been spread and compacted separately are measured, Methods for measuring compaction characteristics.

14. A method for measuring compaction characteristics of a soil material mixture produced by mixing an excavated soil material having a mass fraction of soil passing through a sieve nominal size of 0.15 mm or more in accordance with JIS A 1204 "Soil Grain Size Test Method", cement, and water, comprising: A spreading step of spreading the mixed soil material mixture; A compaction process of compacting the spread soil material mixture after a predetermined time of at least one hour has elapsed since the production of the soil material mixture; and a characteristic measuring step of measuring compaction characteristics of the compacted soil material mixture, In the spreading step, a plurality of the soil material mixtures to which different amounts of admixtures having an effect of delaying the setting reaction of the cement are added are spread separately, In the compaction step, the plurality of soil material mixtures that have been spread separately are each compacted after the same elapsed time has elapsed, In the characteristic measuring step, the compaction characteristics of the plurality of soil material mixtures that have been spread and compacted separately are measured, Methods for measuring compaction characteristics.

15. In the characteristic measuring step, the density of the compacted soil material mixture is measured as the compaction characteristic. A method for measuring compaction characteristics according to any one of claims 1 to 14.

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