Method of manufacturing landfill material

Abstract

This invention provides a landfill material that can be used even when there is a time lag between mixing and dispensing it into water. [Solution] The method for manufacturing landfill material involves mixing soil, a stabilizer, and a setting retarder to produce landfill material in a non-slurry state. The method includes the step of adding a separation inhibitor to the mixed material obtained by the step of mixing soil, a stabilizer, and a setting retarder, in order to prevent the separation of the stabilizer and the soil, and the amount of setting retarder mixed is controlled based on the water content of the soil.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing landfill material. [Background technology]

[0002] Regarding ground improvement measures for reclaimed land, these are generally implemented after the reclamation is complete. However, if the layout plan for facilities and buildings within the reclaimed land is clear in advance, it is possible to shorten the construction period and reduce construction costs by implementing ground improvement measures such as liquefaction prevention, soil pressure reduction, and bearing capacity enhancement simultaneously with the reclamation.

[0003] As a method for creating a stable ground simultaneously with such reclamation, a pre-mixing treatment method is known in which a reclamation mixture, which is a mixture of soil and a stabilizer such as cement and a segregation inhibitor, is poured into water to create the reclamation base (see, for example, Patent Document 1).

[0004] In this type of pre-mixing treatment method, the soil particles are mixed with a stabilizing agent and fixed in place, and a separation inhibitor is added to prevent the separation of soil particles in water. As a result, the particles settle in a nodular form and accumulate on the seabed, creating a dense, stable, and robust reclaimed land base. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Special Publication No. 6-63213 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] When the above landfill mixture material (landfill material) is put into water for landfill, the landfill material may be transported by sea over a long period of time. However, if the transportation takes a long time, there is a risk that the setting and solidification of the stabilizing material (such as cement) in the landfill material will progress during transportation. When the stabilizing material begins to solidify, it is necessary to crush the landfill material and then put it into water, and there is concern about a decrease in the strength of the ground after landfill.

[0007] For this reason, conventionally, in order to be able to put the landfill material into water before the stabilizing material solidifies, the amount of the landfill material transported in one sea transportation has been adjusted, etc. However, since the number of transportation times increases, the efficiency is poor and the cost is also high.

[0008] On one aspect, an object of the present invention is to provide a method for manufacturing a landfill material that can also be used when it takes time from mixing the earth and sand with a stabilizing material or the like until it is put into water.

Means for Solving the Problems

[0009] The first method for manufacturing a landfill material described in this specification is a method for manufacturing a landfill material, which mixes earth and sand, a stabilizing material, and a setting retarder to manufacture a non-slurry landfill material.

[0010] [[ID=​​​​​​​​​​​ [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows an overview of the pre-mixing treatment method. [Figure 2] Figure 2 is a schematic diagram showing the configuration of a workboat according to one embodiment. [Figure 3] Figure 3 is a table showing the soil mix proportions used in experiments to verify the setting retardation performance of setting retarders. [Figure 4] Figure 4(a) is a graph showing the time change in vane shear strength of soil mixtures No. 1 to No. 3 in Figure 3, Figure 4(b) is a graph showing the time change in vane shear strength of soil mixtures No. 4 to No. 6 in Figure 3, and Figure 4(c) is a graph showing the time change in vane shear strength of soil mixtures No. 7 to No. 9 in Figure 3. [Figure 5] Figure 5(a) is a graph showing the change in penetration resistance values ​​over time for soil mixtures No. 1 to No. 3 in Figure 3, Figure 5(b) is a graph showing the change in penetration resistance values ​​over time for soil mixtures No. 4 to No. 6 in Figure 3, and Figure 5(c) is a graph showing the change in penetration resistance values ​​over time for soil mixtures No. 7 to No. 9 in Figure 3. [Figure 6] Figure 6 is a table from Figure 3 with the addition of columns for the rate of coagulation retarder addition, the concentration of the coagulation retarder, the time to the start of coagulation, and the delay in the time to the start of coagulation. [Figure 7] Figure 7(a) is a graph showing the relationship between the setting retarder addition rate Cwt and the setting start time Ts for each of the soil mixtures with cement addition amounts of 50 kg, 100 kg, and 200 kg, respectively. Figure 7(b) is a graph showing the relationship between the setting retarder addition rate Cwt and the setting start time delay RT for each of the soil mixtures with cement addition amounts of 50 kg, 100 kg, and 200 kg, respectively. [Figure 8]Figure 8(a) is a graph showing the relationship between the setting retarder concentration CNO and the setting start time Ts for each of the soil mixtures with cement addition amounts of 50 kg, 100 kg, and 200 kg, and Figure 8(b) is a graph showing the relationship between the setting retarder concentration CNO and the setting start time delay RT for each of the soil mixtures with cement addition amounts of 50 kg, 100 kg, and 200 kg. [Figure 9] Figure 9 is a table showing the soil mix proportions used in experiments to verify the long-term strength development of the setting retarder. [Figure 10] Figure 10(a) is a table showing the uniaxial compressive strength (kN / m2) of each soil mixture (No. 1 to No. 9) at ages of 1, 3, 7, 28, 56, and 91 days, and Figure 10(b) is a table showing the strength ratio of each soil mixture to the strength of the soil mixture without retardant at age 28 days. [Figure 11] Figure 11(a) is a graph showing the change in the strength ratio of soil mixtures No. 1 to No. 3 in Figure 10(b) over time (days), Figure 11(b) is a graph showing the change in the strength ratio of soil mixtures No. 4 to No. 6 in Figure 10(b) over time (days), and Figure 11(c) is a graph showing the change in the strength ratio of soil mixtures No. 7 to No. 9 in Figure 10(b) over time (days). [Figure 12] Figure 12 is a graph plotting the relationship between the setting retarder addition rate Cwt for each soil mixture in Figure 9 and the strength ratios for each soil mixture at ages of 28 days, 56 days, and 91 days in Figure 10(b). [Figure 13] Figure 13 illustrates the daily management of the amount of coagulation retardant added. [Modes for carrying out the invention]

[0014] The following describes one embodiment in detail with reference to Figures 1 to 13. In this embodiment, a method called the pre-mixing treatment method is used when reclaiming land underwater (such as the sea).

[0015] Figure 1 shows an overview of the pre-mixing treatment method. As shown in Figure 1, in the pre-mixing treatment method, first, a treatment is performed in which a stabilizer such as cement is mixed with the soil (step S10). In this mixing treatment, for example, a rotary crushing and mixing method is used. The rotary crushing and mixing method is a method that enables crushing and mixing simultaneously by crushing and granulating the soil and uniformly dispersing the stabilizer through the impact and stirring performance of multiple flexible chains that rotate at high speed inside a cylinder. In this embodiment, in this mixing treatment, a setting retarder is added to the stabilizer and mixed with the soil. This controls (delays) the setting timing of the stabilizer in the ground material (reclaimed material) mixed in the above mixing treatment. As the setting retarder, a setting retarder mainly composed of oxycarbon hydrochloride (for example, "Geolitar 10" ("Geolitar" is a registered trademark) of Floric Co., Ltd.) can be used.

[0016] The landfill material mixed in the above mixing process is in a non-slurry state. A non-slurry state means a state that is substantially non-fluid and can be transported using ordinary dump trucks, etc. Subsequently, a separation inhibitor is added to the landfill material. The separation inhibitor is used to suppress the separation of soil and stabilizers, and is, for example, a polyacrylamide-based polymer flocculant.

[0017] The landfill material, to which separation inhibitors have been added, is transported to a work vessel at sea (Step S12). Heavy machinery such as dump trucks and backhoes, as well as belt conveyors, are used for transportation.

[0018] Subsequently, the reclamation material is transported to a designated location at sea using a work vessel, and the reclamation material is released into the water to carry out reclamation and construction (Step S14).

[0019] In this type of pre-mixing treatment method, the soil particles are mixed with a stabilizing agent and fixed, and the separation of the soil particles in water is prevented by a separation inhibitor, causing them to settle in a nodular form and accumulate on the seabed. Therefore, it is thought that a strong, stable, and uniformly dense reclaimed landmass can be created. For example, since the reclaimed land material mixed on land is transported to a predetermined location at sea by a work vessel, it can take a long time (more than 2 hours) before the mixed reclaimed land material is put into the water. In contrast, in this embodiment, a setting retarder is mixed into the reclaimed land material, so that the stabilizing agent does not solidify on the work vessel.

[0020] (Regarding the workboat) The following describes in detail a workboat according to one embodiment.

[0021] Figure 2 schematically shows the configuration of a work vessel 100 according to one embodiment. The work vessel 100, also called a gut purge vessel, comprises a work vessel body 10 capable of loading reclamation materials in a cargo hold 12, and a crane device 20 installed on the work vessel body 10, as shown in Figure 2. In Figure 2, the vertical direction is defined as the Z-axis direction, and the two orthogonal axes in the horizontal plane are defined as the X-axis direction and the Y-axis direction.

[0022] The crane device 20 comprises a main body device 30, a boom 22 provided on the main body device 30, a clamshell bucket 24 as a discharge device, and a wire 28 for suspending and holding the clamshell bucket 24. The main body device 30 has a cockpit (not shown) and can rotate around the Z-axis in response to the operator's movements from the cockpit. The main body device 30 also adjusts the three-dimensional position of the clamshell bucket 24 by adjusting the posture, length, and elevation angle of the boom 22, and by adjusting the winding amount of the wire 28, in response to the operator's movements. The main body device 30 also performs opening and closing operations of the clamshell bucket 24 via a wire rope (not shown) in response to the operator's movements. By closing the clamshell bucket 24 while it is in contact with the landfill material in the ship's hold 12, the clamshell bucket 24 can hold the landfill material. Furthermore, by opening the clamshell bucket 24 underwater while it is holding the landfill material, the landfill material can be discharged towards the seabed. In Figure 2, a caisson (quay) 40 has been installed in the sea beforehand, and the area on the +X side of the caisson 40 is the area to be reclaimed and constructed.

[0023] (Regarding experimental examples) The following describes an experimental example to verify the performance of the setting retarder. The objectives of this experiment are (1) to confirm the setting retarder performance of the mixed soil when the setting retarder is applied to the pre-mixing treatment method, and (2) to confirm the strength development of the mixed soil when the setting retarder is mixed into the filler material.

[0024] (1) Regarding condensation delay performance To verify the setting retardation performance of the soil mixture using a setting retarder, vane shear tests and penetration tests were conducted.

[0025] (Experimental conditions) 1.Materials used For the soil sample, sand (Kakegawa mountain sand, natural moisture content 2.2%) was prepared, and for the cement (stabilizer), blast furnace cement type B (Taiheiyo Cement Corporation) was prepared. In addition, tap water was prepared as the mixing water, and Diolitter 10 (Floric Co., Ltd.) was prepared as a setting retarder. 2.Composition As shown in Figure 3, 1 m³ of mixed soil 3 For the sample, the dry weight of the soil (sand) was 1679 kg, and the mixing water (tap water) was 252 kg. Additionally, 1 m³ of the mixed soil was used. 3 In this experiment, we prepared nine different soil mixtures (No. 1 to No. 9) by varying the amount of cement added (50 kg, 100 kg, and 200 kg) and the amount of setting retarder added (0 kg (no additive), 2 kg, and 4 kg). Regarding the amount of mixing water, the moisture content of the soil sample was measured, and the amount of water added (tap water + setting retarder) was adjusted so that the moisture content was 15%. The setting retarder was added as part of the mixing water.

[0026] (Regarding the results of the vane shear test) The vane shear test is a test in which vanes, called blades, are rotated in a soil mixture, and the vane shear strength of the soil mixture is determined from the resistance to rotation.

[0027] Figure 4(a) is a graph showing the time change in vane shear strength of soil mixtures No. 1 to No. 3 in Figure 3. Figure 4(b) is a graph showing the time change in vane shear strength of soil mixtures No. 4 to No. 6 in Figure 3. Figure 4(c) is a graph showing the time change in vane shear strength of soil mixtures No. 7 to No. 9 in Figure 3. From these graphs, it can be seen that regardless of whether the amount of cement added is 50 kg, 100 kg, or 200 kg, by adding a setting retarder, the predetermined shear strength (for example, 30 kN / m) can be increased. 2 It can be seen that the time required to obtain the desired result can be extended. Furthermore, it can be seen that the delaying effect depends on the amount of coagulation retardant added.

[0028] (Regarding the results of the penetration test) The penetration test is a test in which a penetration resistance test device having a mechanism for applying a penetration force to a penetration needle via hydraulic pressure or a spring is used to measure the force required when the penetration needle penetrates the mixed soil, and the penetration resistance value is obtained by dividing the measured force by the cross-sectional area of the penetration needle.

[0029] Figure 5(a) is a graph showing the change over time of the penetration resistance values of the No. 1 to No. 3 mixed soils in Figure 3. Figure 5(b) is a graph showing the change over time of the penetration resistance values of the No. 4 to No. 6 mixed soils in Figure 3. Figure 5(c) is a graph showing the change over time of the penetration resistance values of the No. 7 to No. 9 mixed soils in Figure 3. For example, similar to the index shown in the concrete setting time test method of JIS A 1147:2019, when the time until the penetration resistance value reaches 3.5 N / mm 2 is taken as the start time of setting (initial setting time), it can be said from Figures 5(a) to 5(c) that as the amount of cement added increases, the initial setting time becomes shorter, and as the amount of setting retarder added increases, the initial setting time becomes longer.

[0030] (Regarding the start time of setting) Here, the present inventor examined a method for calculating the start time of setting of the mixed soil based on the results of the above penetration test.

[0031] Figure 6 is a table in Figure 3 with the columns (items) of setting retarder addition rate, setting retarder concentration, initial setting time, and start time delay added. The setting retarder addition rate Cwt means the ratio of the amount of setting retarder added G 10 to the amount of cement added C (Cwt = G 10 / C × 100 [%]). Also, the setting retarder concentration C NO means the ratio of the amount of setting retarder added G 10 to the amount of water added (water content) W (C NO = G 10 / W × 100 [%]). Also, the initial setting time Ts means the time until the penetration resistance value reaches 3.5 N / mm 2 and can be obtained from the graphs in Figures 5(a) to 5(c).

[0032] Start time delay R TThis refers to the magnitude of the setting start time for each soil mixture, relative to the setting start time of a soil mixture with the same amount of cement added and no setting retarder added. For example, the setting start time delay R of soil mixture No. 2. T This is the value obtained by dividing the initial setting time of soil mixture No. 2 by the initial setting time of soil mixture No. 1 (7.97 / 5.08=1.57), and the initial setting time delay R of soil mixture No. 3. T This is the value obtained by dividing the initial setting time of soil mixture No. 3 by the initial setting time of soil mixture No. 1 (29.23 / 5.08=5.75). Also, the initial setting time delay R of soil mixture No. 1. T This is the value obtained by dividing the initial setting time of soil mixture No. 1 by the initial setting time of soil mixture No. 1 (= 1, .00). Similarly, the initial setting time delay R of soil mixtures No. 4 to 6. T This value is obtained by dividing the initial setting time of soil mixtures No. 4-6 by the initial setting time of soil mixture No. 4, and the initial setting time delay R of soil mixtures No. 7-9. T This value is obtained by dividing the initial setting time of soil mixtures No. 7 to 9 by the initial setting time of soil mixture No. 7.

[0033] Figure 7(a) is a graph showing the relationship between the setting retarder addition rate Cwt and the setting start time Ts for each of the soil mixtures with cement addition amounts of 50 kg, 100 kg, and 200 kg. Figure 7(b) shows the relationship between the setting retarder addition rate Cwt and the setting start time delay R for each of the soil mixtures with cement addition amounts of 50 kg, 100 kg, and 200 kg. T This graph shows the relationship between the two factors. In the graphs in Figures 7(a) and 7(b), the amount of cement added affects the delay in the setting start time. To eliminate this effect of the amount of cement added, the inventors have replaced the setting retarder addition rate Cwt on the horizontal axis of Figures 7(a) and 7(b) with the setting retarder concentration C NO We decided to use this.

[0034] Figure 8(a) shows the setting retarder concentration C for each soil mixture with cement addition amounts of 50 kg, 100 kg, and 200 kg. NOThis is a graph showing the relationship between the setting start time Ts. Figure 8(b) shows the setting retarder concentration C for each soil mixture with cement addition amounts of 50 kg, 100 kg, and 200 kg. NO And, the first train is late. T This graph shows the relationship with the coagulation retarder concentration C. NO The relationship between the setting retarder concentration C and the setting start time Ts can be expressed as an exponential function for each amount of cement added, as shown in Figure 8(a). NO And the first train is late. T Regarding the relationship between the two factors, it was found that the effect of the amount of cement added becomes small, and it can be expressed by a single approximation formula (exponential function) as shown in Figure 8(b).

[0035] (2) Strength development of mixed soil with added setting retarder (Experimental conditions) 1.Materials used For the soil sample, sand (Kakegawa mountain sand, natural moisture content 2.2%) was prepared, and for the cement, blast furnace cement type B (Taiheiyo Cement Corporation) was prepared. In addition, tap water was prepared as the mixing water, and Diolitter 10 (Floric Co., Ltd.) was prepared as a setting retarder. 2.Composition As shown in Figure 9, 1 m³ of mixed soil 3 For the sample, the dry weight of the soil (sand) was 1679 kg, and the mixing water (tap water) was 252 kg. Also, 1 m³ of the mixed soil was used. 3 For each mixture, the amount of cement added was set to three levels (50 kg, 100 kg, 200 kg), and the amount of setting retarder added was also set to three levels (0 kg (no additive), 2 kg, 4 kg), resulting in nine types of mixed soil (No. 1 to No. 9). The water-cement ratio (= amount of water added W / amount of cement added C × 100 [%]), moisture content (= amount of water added W / amount of sand S × 100 [%]), and setting retarder addition rate Cwt (= amount of setting retarder added G) were also determined for each mixed soil. 10 The amount of cement added (C × 100 [%]) is as shown in Figure 9. The curing temperature of the test specimens was 20°C.

[0036] (Regarding the results of the unconfined compressive strength test) Figure 10(a) shows the unconfined compressive strength (kN / m²) of each soil mixture (No.1 to No.9) at ages of 7, 28, 56, and 91 days. 2 Figure 10(b) is a table showing the uniaxial compressive strength (strength ratio) of each soil mixture with the same amount of cement added, compared to the uniaxial compressive strength of a soil mixture without a setting retarder at 28 days of age. For example, the strength ratio of each soil mixture No. 2 at each age is calculated by taking the strength of each soil mixture No. 2 at each age and setting it to the strength of soil mixture No. 1 at 28 days (1338 kN / m²). 2 The strength ratio for each age of mixed soil No. 3 is obtained by dividing the strength of mixed soil No. 3 at each age by the strength of mixed soil No. 1 at 28 days, and the strength ratio for each age of mixed soil No. 1 is obtained by dividing the strength of mixed soil No. 1 at each age by the strength of mixed soil No. 1 at 28 days (see the first thick-lined box from the top in Figure 10(b)). Similarly, the strength ratio for each age of mixed soil No. 4 to 6 is obtained by dividing the strength of mixed soil No. 4 to 6 at each age by the strength of mixed soil No. 4 at 28 days (2500kN / m 2 The value obtained by dividing by ) is the strength ratio of each age of mixed soil No. 7 to 9, and the strength of each age of mixed soil No. 7 to 9 is the strength of mixed soil No. 7 at 28 days (8021 kN / m²). 2 This is the value obtained by dividing by (see the second and third thick-lined boxes from the top in Figure 10(b)).

[0037] Figure 11(a) is a graph showing the change in the strength ratio of soil mixtures No. 1 to No. 3 in Figure 10(b) over time (days), Figure 11(b) is a graph showing the change in the strength ratio of soil mixtures No. 4 to No. 6 in Figure 10(b) over time (days), and Figure 11(c) is a graph showing the change in the strength ratio of soil mixtures No. 7 to No. 9 in Figure 10(b) over time (days).

[0038] From the graphs in Figures 11(a) to 11(c), it can be seen that when the amount of cement added is small (50 kg / m³). 3 In this case, even with the addition of 2 kg of setting retarder, the strength reached at 91 days was almost the same as that of the unadded mixture (soil mixture No. 1) at 28 days. On the other hand, when the amount of cement added is large (100 kg / m³), it can be seen that the strength reached at 91 days is almost the same as that of the unadded mixture (soil mixture No. 1) at 28 days.3 , 200 kg / m 3 In this case, even with the addition of 2 kg of setting retarder, the strength at 56 days of age is higher than that of the wood at 28 days of age without the additive (No. 4, No. 7), indicating that the setting retarder has little effect on the development of strength.

[0039] Figure 12 is a graph plotting the relationship between the setting retarder addition rate Cwt for each soil mixture in Figure 9 and the strength ratios for each soil mixture at 28 days, 56 days, and 91 days of age in Figure 10(b).

[0040] Figure 12 shows that when the setting retarder addition rate Cwt is 2% or less, the strength of the soil mixture at 56 days is greater than the strength of the soil mixture without the additive at 28 days (strength ratio = 1.00). Therefore, it can be said that if the setting retarder addition rate Cwt is 4% or less, the amount of setting retarder added will not affect the development of the soil mixture's strength.

[0041] (Method for controlling the amount of cement and setting retarder added on site) The following describes the method for managing the amount of cement and setting retarder added on site. This management method takes into account the experimental results mentioned above and involves (1) determining the amount of cement to be added to the mixed soil used as filler material, (2) conducting a setting retardation performance test when a setting retarder is added to the mixed soil, (3) conducting a strength development confirmation test when a setting retarder is added to the mixed soil, and (4) managing the amount of setting retarder added on a daily basis. (1) Regarding the amount of cement to be added The amount of cement to be added is usually determined by indoor mix design tests. These indoor mix design tests are conducted using conventionally known methods, and the test conditions are as follows: a) Use soil and cement used in reclamation work. b) The time from manufacturing (mixing) to embankment / filling is assumed to be within 2 hours. c) The curing temperature of the test specimens shall be the standard curing temperature (20°C). d) No setting retarder shall be added (0 kg).

[0042] (2) Tests on the setting retardation performance when a setting retarder is added. The setting delay performance test will be conducted according to the following procedure. a) Set the cement addition amount to at least one level under the expected ambient temperature at the site. If the indoor mix design test described in (1) above is not performed, the cement addition amount may be set based on past construction results. b) Coagulation retarder addition rate Cwt (amount of coagulation retarder added G) 10 By setting the cement addition amount (C × 100 [%)) to at least three levels (e.g., 0%, 2%, 4%) and conducting penetration tests on each soil mixture, the penetration resistance value was determined to be 3.5 N / mm². 2 Calculate the time it takes for each to reach the desired state (initial condensation time). c) Determine the water content W from the water content ratio of the soil used in the test, and determine the concentration C of the setting retarder. NO (= Amount of coagulation retardant added G) 10 Calculate the moisture content (W × 100 [%]). d) Analyze the relationship between the time of initial condensation and the concentration of the condensation retarder (see Figure 8(a)) and derive an approximate formula (a predictive formula that predicts the time of initial condensation from the concentration of the condensation retarder). Note that the condensation retarder concentration C shown in Figure 8(b) is obtained from the test results. NO And the first train is late. T If a relationship can be obtained, an approximate formula (a prediction formula that predicts the delay in the start time from the coagulation retarder concentration) as shown in Figure 8(b) may be obtained.

[0043] (3) Confirmation test of strength development when a setting retarder is added The strength development confirmation test will be performed according to the following procedure. a) Set at least three levels of setting retarder addition rate Cwt (e.g., 0%, 2%, 4%), and for each level, conduct uniaxial compressive strength tests at 7, 28, 56, and 91 days of age to confirm the combination of age and setting retarder addition rate Cwt that satisfies the design strength. b) Determine the timing of the quality control test after the completion of the landfill work based on the results of the uniaxial compressive strength tests at each of the above-mentioned ages. For example, even if it is usually decided to judge the pass or fail of the strength 28 days after the completion of the landfill work, if it is confirmed from the results of the above uniaxial compressive strength test that the design strength is satisfied at the age of 56 days, the timing of the pass or fail judgment of the strength is delayed (for example, the pass or fail judgment is made on the 56th day after the completion of the work). Here, determine the higher one among the combinations of the addition rates Cwt of the setting retarder corresponding to the timing (age) of the quality control test to be determined as the threshold value.

[0044] (4) Regarding the daily management of the addition amount of the setting retarder a) As a daily management item, continuously measure the moisture content (water content ratio) of the earth and sand used (the measurement time interval is, for example, a fixed time arbitrarily set within 1 hour). b) According to the machinery and methods for transporting and underwater inputting of the landfill materials on the working day, set the time (required time T n ) until the input of the landfill materials of the same production lot is completed at the landfill site. When setting this required time Tn, consider the transportation time to the landfill site and the amount of landfill materials loaded on the workboat 100. When the amount of landfill materials loaded on the workboat 100 (for example, a closed earth transport ship) increases, the time required for loading becomes longer. Also, when the amount of landfill materials increases, the time until the input of the landfill materials of the same production lot is completed at the landfill site varies depending on the position (depth) in the hold 12 of the workboat main body 10 where the materials are loaded.

[0045] For example, as shown in Fig. 13, for the landfill materials (1) stored at the bottom of the hold 12 of the workboat main body 10, set it as the required time T1, and for the landfill materials (2) stored above it, set it as the required time T2 (T2 < T1). Also, for the landfill materials (3) stored above the landfill materials (2), set it as the required time T3 (T3 < T2 < T1). And the initial setting time of the landfill materials is the set required time T nDetermine the addition amount of the setting retarder so that it becomes longer. Here, when determining the addition amount of the setting retarder, the prediction formula obtained in advance through the setting retardation performance test, the water content of the earth and sand when manufacturing the landfill material, and the setting retardation effect required for the landfill material (the start time of setting ≥ required time T n ) are used to determine the amount of the setting retarder to be added. At this time, if the addition amount of the setting retarder can be determined based on the results of the strength development confirmation test so that the addition rate Cwt of the setting retarder is below the threshold value, it becomes possible to ensure the designed strength of the mixed soil used as the landfill material.

[0046] In the example of Fig. 13, since T3 < T2 < T1, the addition amount G(T1) of the setting retarder for the landfill material (1) is larger than the addition amounts G(T2) and G(T3) of the setting retarder for the landfill materials (2) and (3). Also, the addition amount G(T2) of the setting retarder for the landfill material (2) is larger than the addition amount G(T3) of the setting retarder for the landfill material (3). At this time, a landfill material transportation plan will be made such that any addition amount of the setting retarder falls within the upper limit value obtained in advance.

[0047] As described above, when managing the amount of the setting retarder added to the landfill material and performing the mixing process (S10) in Fig. 1, appropriately adjust the addition amount of the setting retarder.

[0048] As described in detail above, according to the present embodiment, since the earth and sand, the stabilizing material (cement), and the setting retarder are mixed to produce a non-slurry landfill material, the start time of setting becomes longer because the setting retarder is added to the non-slurry landfill material. Therefore, even when it takes time to transport the landfill material, it becomes possible to put it into the water before the landfill material solidifies. Also, even if the setting retarder is added, if the addition amount is appropriate, the landfill material can exhibit long-term strength development performance, so it becomes possible to ensure the strength of the landfill ground.

[0049] Furthermore, according to this embodiment, soil, a stabilizer (cement), and a setting retarder are mixed, and a separation inhibitor is added to the resulting filler material to prevent the separation of the soil, stabilizer, and setting retarder. As a result, the separation of the stabilizer, soil particles, and water containing the setting retarder is suppressed in the water, causing the filler material to settle in a nodular form and accumulate on the seabed. This makes it possible to create a strong, stable, and uniformly dense reclaimed landmass.

[0050] Furthermore, according to this embodiment, the landfill material is manufactured by mixing soil, a stabilizer, and a setting retarder, and the required setting start time Ts and setting start time delay R for the landfill material are determined. T Accordingly, the amount of setting retarder mixed in is controlled based on the water content (moisture content W) of the soil. This makes it possible to mix in only the appropriate amount of setting retarder according to the initial setting time required for the landfill material.

[0051] In this case, the amount of coagulation retarder added G 10 The concentration of the setting retarder C is determined from the water content (moisture content W) of the soil. NO And, the condensation delay effect of condensation retardants (condensation start time Ts and start time delay R) T The relationship between ( ) and ( ) is identified (Figures 8(a) and 8(b)), and the amount of setting retarder to be added is determined based on the identified relationship, the water content of the soil when manufacturing the landfill material, and the required setting retardation effect (and amount of cement) in the landfill material. This makes it possible to determine the optimal amount of setting retarder to be added.

[0052] Furthermore, the relationship between the setting retarder addition rate Cwt, which is determined from the amount of cement and the amount of setting retarder, and the strength development of the mixed soil is identified (Figure 12). Based on this identified relationship, the amount of cement used when manufacturing the filler material, and the design strength that the filler material must ensure, the amount of setting retarder to be added is determined. This makes it possible to determine the optimal amount of setting retarder to be added.

[0053] Furthermore, the landfill material in this embodiment is transported by ship and dumped into the water. The amount of setting retarder to be added is determined based on the transport time of the landfill material, the amount of landfill material loaded onto the work vessel 100, and the loading location. This makes it possible to determine the optimal amount of setting retarder to be added.

[0054] The embodiments described above are preferred examples of the present invention. Furthermore, the invention can also be implemented when transporting mixed soil by dump truck, even when long-distance transport or road congestion is expected to increase transport time. However, the invention is not limited thereto, and various modifications are possible without departing from the spirit of the present invention. [Explanation of Symbols]

[0055] 10 Workboat Body 12 Ship's hold 20 Crane equipment 24 Clamshell Buckets 100 workboats

Claims

1. A method for manufacturing landfill material, which involves mixing soil, a stabilizer, and a setting retarder to produce landfill material in a non-slurry state.

2. The process involves mixing soil, a stabilizer, and a setting retarder. A step of manufacturing landfill material by adding a separation inhibitor to the mixed material obtained by the mixing step, which prevents the separation of the stabilizer and the soil, A method for manufacturing landfill material containing

3. The process includes a step of mixing soil, a stabilizer, and a setting retarder to manufacture landfill material. A method for manufacturing landfill material, wherein the amount of the setting retarder to be mixed is controlled based on the water content of the soil.

4. The process includes determining the relationship between the amount of the setting retarder, the water content of the soil, and the setting retarder's effect on delaying the setting. A method for manufacturing a landfill material according to claim 3, wherein the amount of the setting retarder to be mixed is determined based on the above relationship, the water content of the soil used in the process of manufacturing the landfill material, and the setting retardation effect required for the landfill material.

5. A method for manufacturing landfill material according to claim 3, wherein the amount of the setting retarder to be mixed is controlled based on the water content of the soil and the amount of the stabilizer.

6. The process includes determining the relationship between the amount of the setting retarder, the water content of the soil, and the setting retarder's effect on delaying the setting, and the relationship between the amount of the stabilizing agent, the amount of the setting retarder, and ensuring the strength of the filler material. A method for manufacturing a landfill material according to claim 5, wherein the amount of the setting retarder to be mixed is determined based on each of the aforementioned relationships, the water content of the soil used in the process of manufacturing the landfill material, the amount of the stabilizer, the setting retardation effect required for the landfill material, and the strength that the landfill material should secure.

7. The aforementioned landfill material is landfill material that is transported by ship and dumped into the water. A method for manufacturing landfill material according to any one of claims 1 to 6, wherein the amount of the setting retarder to be mixed is determined according to at least one of the transport time by the ship and the amount of landfill material loaded onto the ship.

8. The method for manufacturing landfill material according to claim 7, wherein the amount of the setting retarder to be mixed with the landfill material is determined according to the loading position of the landfill material on the ship.

9. The method for producing landfill material according to any one of claims 1 to 6, wherein the setting retarder mainly comprises oxycarbon hydrochloride.

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