JP6210400B2 - Steelmaking slag mixing method for soft soil - Google Patents

Description

The present invention relates to a method of mixing steelmaking slag with soft soil for improving the strength of soft soil by mixing steelmaking slag generated as a by-product in the refining process of steel with soft soil such as clay.

  Conventionally, calcia-modified soil, which improves strength of soft soil by mixing steelmaking slag generated as a by-product in the steel refining process with soft soil such as dredged soil, is used as a civil engineering material for ground, tidal flats, shallow ground preparation materials, etc. A method of use has been proposed (see, for example, Patent Document 1, paragraph 0035).

  As a method of mixing steelmaking slag with soft soil such as dredged soil, steelmaking slag is added at a predetermined ratio to a certain amount of soft soil put into a stirring device such as a mechanical mixer, and it is stirred by a stirring device. The method of mixing forcibly and the method of mixing in the pipe, in which steelmaking slag added to soft soil in a specified ratio is pneumatically fed and stirred using the turbulent effect of the plug flow generated in the pumping pipe A method of adding steelmaking slag at a predetermined ratio to soft soil stored in a ship or the like and forcibly stirring it with a backhoe is known.

  In addition, as a method for easily mixing a large amount of two substances, a method of mixing using a belt conveyor connection is also known (see, for example, Non-Patent Document 1).

  Furthermore, as another method of mixing the soft soil and the additive, the soft soil to which the additive is added is put into a tall tower-shaped cylindrical kneading device, and the inside of the device is dropped. It is also conceivable to mix soft soil and additives using, for example, Patent Document 2).

JP 2009-121167 A JP 11-28719 A Pre-mixing treatment method technical manual (revised version) Coastal Technology Research Center, December 2008, p. 61

  However, in the mixing method and the mixing method in the pipe using the conventional stirring device as described above, a dedicated facility is required, so the facility must be large. For example, in the mixing method in the pipe In this case, a reclaimer ship for supplying steelmaking slag, a pneumatic ship for mixing and feeding soft soil and steelmaking slag are required, and there is a problem that construction costs increase.

  On the other hand, the mixing method using a backhoe can be easily and inexpensively constructed using a general-purpose machine, but is not suitable for mass construction.

  The mixing method using the belt conveyor connection is mainly for mixing dry sand or sandy soil with a low water content and cement, such as dredged soil with a high silt / clay content. It is not suitable for mixing soft soil with a high water content and steelmaking slag, and when applied to mixing soft soil and steelmaking slag, soft soil such as dredged soil and steelmaking slag are not sufficiently mixed. Forcible mixing with a biaxial mixer or the like must be performed separately, and the facility was inevitably large as in the mixing method using a stirring device.

  In addition, in the method of mixing soft soil and additives using falling energy, a tall and unstable tower-type kneading device is used, so the kneading device needs to be installed in a stable state. In addition, there is a problem that the equipment becomes large and the installation place is limited, and such a kneading apparatus is often provided with a stirring means such as a paddle that operates with electric power in order to obtain a sufficient mixing state. There is a demand for the development of an apparatus capable of mixing soft soil and steelmaking slag with a simpler structure.

Then, in view of such a conventional problem, the present invention was made for the purpose of providing a steelmaking slag mixing method for soft soil that can easily and inexpensively mix soft soil such as clay and steelmaking slag. It is.

The feature of the invention according to claim 1 for solving the conventional problem as described above is that the steelmaking slag is added at a predetermined ratio to a certain amount of soft soil, and the steelmaking slag and soft soil are mixed. In the steelmaking slag mixing method with respect to the soil, a plurality of belt conveyors installed such that the discharge side end of the upstream belt conveyor is higher than the input side end of the downstream belt conveyor by a predetermined drop height A water content ratio adjusting means for adjusting the water content ratio of the soft soil introduced into the transfer means, and a slag for adding steelmaking slag at a predetermined ratio to a certain amount of soft soil upstream of the transfer means. Using a mixing device comprising a supply means and a mixing promoting means comprising one or a plurality of mixing repellent members disposed at a predetermined collision distance below the discharge side end of each belt conveyor; and Before the most downstream The discharge side end of the belt conveyor is set to be higher than the discharge destination ground by the predetermined drop height, and a shoulder surface inclined in the discharge direction is formed on the discharge destination ground portion. The shoulder surface is a collision surface portion of the mixing repellent, and the moisture content of the soft soil is adjusted by the moisture content adjusting means so as to have an appropriate viscosity and fluidity. Steelmaking slag is added to the soft soil at a predetermined ratio from the slag supply means on the upstream side of the transfer means, and then the soft soil to which the steelmaking slag is added is directed downstream by the belt conveyors. While transferring, the soft soil added with the steelmaking slag is dropped from the discharge side end of the belt conveyor to collide with the repellent for mixing, the soft soil added with the steelmaking slag after the collision is the Downstream belt belt Repeat fall mixing operation to be put into the side end portion of the bare every transfer technique between each belt conveyor is to mixing the steelmaking slag and soft soil.

The feature of the invention described in claim 2 is that, in addition to the configuration of claim 1, the water content ratio having the appropriate viscosity and fluidity is 1.2 to 1.6 times the liquid limit. Features.

  As described above, the steelmaking slag mixing method for the soft soil according to the present invention adds the steelmaking slag at a predetermined ratio to a certain amount of soft soil, and mixes the steelmaking slag with the soft soil to improve the calcia. In the steelmaking slag mixing method for soft soil that produces soil, it is installed so that the discharge side end of the upstream belt conveyor is higher than the input side end of the downstream belt conveyor by a predetermined drop height. Steel making at a predetermined ratio to a certain amount of soft soil upstream of the transfer means, transfer means having a plurality of belt conveyors, water content adjusting means for adjusting the water content ratio of the soft soil put into the transfer means Slag supply means for adding slag, and mixing promoting means comprising one or a plurality of mixing repellent members arranged at a predetermined collision distance below the discharge side end of each belt conveyor. Mixing effect using impact and repulsion when colliding with the repelling material for mixing by adjusting the water content ratio of the soft soil so as to have an appropriate viscosity and fluidity by the water content ratio adjusting means using a combined device Can be obtained.

  Further, after the soft soil adjusted in water content ratio is introduced into the transfer means, steelmaking slag is added to the soft soil at a predetermined ratio from the slag supply means on the upstream side of the transfer means, and then the steelmaking While the soft soil added with slag is transferred toward the downstream side by each belt conveyor, the soft soil added with steelmaking slag is dropped from the discharge side end of the belt conveyor, The steelmaking slag is repeated for each connection between the belt conveyors, and a drop mixing operation in which the soft soil to which the steelmaking slag that has undergone the collision is added is input to the input end of the downstream belt conveyor is repeated. By mixing the soil and soft soil, the soft soil and steelmaking slag are made efficient by utilizing the falling energy and the impact and repulsion when colliding with the mixing repellent during the series of transfer work by the transfer means. It is possible to Ku mixed.

  Furthermore, in the present invention, the discharge side end of the most downstream belt conveyor is installed at a position higher than the discharge destination ground by the predetermined fall height, and the discharge direction to the discharge destination ground portion is set. The sloping shoulder surface is formed and mixed with the shoulder surface as the collision surface of the mixing repellent, so that the discharge work to the discharge destination such as landfill can be used for mixing soft soil and steelmaking slag. can do.

  Further, in the present invention, the water content ratio having the appropriate viscosity and fluidity is 1.2 to 1.6 times the liquid limit, which is suitable for mixing with steelmaking slag by the method of the present invention. Cohesive soil can be obtained.

It is a schematic side view which shows an example of the mixing apparatus which concerns on this invention. It is a partial expanded side view which shows the outline of the transfer part between each belt conveyor in FIG. It is a partial expanded side view which shows other embodiment same as the above. It is a schematic front view of the mixing promotion means for demonstrating the principle of the drop kneading operation | work in the steel-making slag mixing method with respect to the soft soil which concerns on this invention. It is a graph which shows the result of the reference experiment which verified about the influence which the collision distance in this invention method has on the quality of calcia reformed soil.

  Next, an embodiment of the mixing apparatus according to the present invention will be described based on the embodiment shown in FIGS. In addition, the code | symbol A in a figure is a landfill site which is a transfer destination of calcia reforming soil.

  This mixing device 1 includes a transfer means 3 having a plurality of belt conveyors 2, 2..., A moisture content adjusting means (not shown) for adjusting the moisture content of the soft soil 4 put into the transfer means 3, and a transfer means 3 Slag supply means 6 for adding steelmaking slag 5 at a predetermined ratio to the soft soil 4 cut out at a fixed amount on the upstream side of the soil, and the soft soil 4 and the steelmaking slag 5 that have been put into the landfill A or the like The soft soil 4 and the steelmaking slag 5 are mixed while being transferred to the transfer destination.

  For example, as shown in FIG. 1, the transfer means 3 is composed of an unloading ship (reclaimer ship) 10 floating on the water and a plurality of floating conveyors 11, 11 floating on the water. The soft soil 4 such as dredged soil is unloaded from 13, cut into fixed amounts, and sequentially supplied to the uppermost belt conveyor 2.

  Reference numeral 14 in the figure denotes a soft soil supply hopper 14 equipped with a feeder capable of adjusting the discharge amount, and soft soil 4 such as dredged soil pumped from the ship carrier 13 by the backhoe 12 or the like is used as soft soil. It is inserted into the supply hopper 14, cut into fixed amounts, and sequentially supplied to the most upstream belt conveyor 2.

  The water content ratio adjusting means is arranged upstream of the transfer means 3 such as a hydrating device for adding water to the soft soil 4 mounted on the earth vessel 13 and is suitable for mixing the soft soil 4 with the steelmaking slag 5. It is supposed to adjust to.

  The moisture content of the soft soil 4 is 1.2 to 1.6 times the liquid limit (wL), and the soft soil 4 has an appropriate viscosity and fluidity. Specifically, the cylinder flow test (JHS A 313) The flow value is adjusted so as to be 85 to 250 mm.

  The slag supply means 6 includes, for example, a hopper 15 having a feeder capable of adjusting the discharge amount, and a slag supply belt conveyor 16 disposed on the most upstream belt conveyor 2, and is cut out by a feeder at regular intervals. The steelmaking slag 5 is sequentially added to the soft soil 4 on the belt conveyor 2 by the belt conveyor 16 for supplying slag, and the steelmaking slag 5 is added to the soft soil 4 at a predetermined ratio (10 to 40 vol%) in layers. It has become.

  It should be noted that the steelmaking slag 5 to be supplied has a large disturbing effect in soft soil if it has a certain size and a large weight, and the steelmaking slag having a particle size of 10 mm to 25 mm contains 20% or more of the entire steelmaking slag. Is preferred.

  As shown in FIG. 1, each belt conveyor 2, 2... Is installed in an inclined arrangement so that the input side end 2 a is low and the discharge side end 2 b is high. The soft soil 4 to which the discharge side end portion 2b is positioned so as to be higher than the input side end portion 2a of the downstream belt conveyor 2 by a predetermined drop height H in the vertical direction and to which the steelmaking slag 5 is added is provided. Each time the belt conveyors 2, 2... Are connected, they are discharged and dropped from the discharge side end 2 b of the upstream belt conveyor 2, and the soft soil 4 and the steelmaking slag 5 are utilized by using the falling energy at that time. And mix.

  The drop height H is set to such a height that a mixing effect using the drop energy can be expected when the soft soil 4 and the steelmaking slag 5 are mixed.

  In addition, the mixing device 1 includes one or a plurality of mixing repellent bodies 20 disposed at a predetermined collision distance D below the discharge side end 2b of each belt conveyor 2, 2. The soft soil 4 to which the steelmaking slag 5 discharged from the upstream belt conveyors 2, 2... Is added and collides with the mixing repelling body 20 through the downstream belt. By being put into the conveyor 2, the mixing of the soft soil 4 and the steelmaking slag 5 is promoted for each transfer between the belt conveyors 2 and 2.

  As the mixing repellent 20, for example, a flat steel plate having a certain hardness is used, and the soft soil 4 is utilized by utilizing the impact and repulsion when the soft soil 4 and the steelmaking slag 5 collide with the steel plate. And the steelmaking slag 5 are kneaded.

  In addition, the mixing repelling body 20 is arranged so that the collision surface portion 21 forms an angle θ with respect to the horizontal plane, and generates a repulsive force on the soft soil 4 and the steelmaking slag 5 and the collision surface portion 21 is disposed at an inclination. Thus, the soft soil 4 to which the steelmaking slag 5 that has undergone the collision is added draws a falling trajectory toward the mixing repellent 20 below or the input side end 2a of the belt conveyor 2. In addition, it is preferable that angle (theta) shall be 0-60 degree | times according to a fall locus | trajectory.

  When the angle θ is small, soft soil to which steelmaking slag is added may remain on the mixing repellent body 20, and in that case, sliding on the collision surface portion on the mixing repellent body 20. Discharge means for forcibly discharging the soft soil to which the remaining steelmaking slag is added toward the input side end 2a of the belt conveyor 2 may be provided.

  The predetermined collision distance D is at least 1 m, preferably 2 m or more. When a plurality of mixing repellent bodies 20 are provided, the mixing repellent bodies 20 and 20 are arranged so as to be separated from each other by a collision distance D in the vertical direction.

  The mixing repellent 20 was a hopper having a tapered cylindrical funnel portion 20a that shrinks downward under the cylindrical charging portion, and the steelmaking slag 5 was added to the inner surface of the funnel portion 20a. It is good also as the collision surface part 21 which makes the soft soil 4 collide.

  Further, when the mixing promoting means 22 includes a plurality of mixing repellent bodies 20, each mixing repellent body 20, 20 is installed in accordance with the dropping trajectory of the soft soil 4, and as shown in FIG. , 21 may be provided stepwise toward the discharge side, and as shown in FIG. 3, the collision surface portions 21, 21 may be provided in a staggered arrangement with their orientations changed vertically.

  Each mixing repellent body 20 is installed via a fixed frame 23 installed on a carriage, and the collision distance D can be set by adjusting the height relative to the fixed frame 23.

  Next, a steelmaking slag mixing method for soft soil using such a mixing apparatus 1 will be described. In addition, the same code | symbol is attached | subjected and demonstrated to the structure similar to the above-mentioned Example.

  First, the water content ratio of the soft soil 4 such as dredged material carried by the soil carrier 13 is measured in advance, and then the soft soil 4 is mixed with the steelmaking slag 5 by adding water using a water content ratio adjusting means. Suitable for use, ie, having a suitable viscosity and fluidity (the moisture content of the soft soil 4 is 1.2 to 1.6 times the liquid limit, and the flow value of the cylinder flow test (JHS A 313) is 85. To 250 mm).

  Next, the soft soil 4 whose water content ratio is adjusted is pumped up by the backhoe 12 or the like, and is put into the soft soil supply hopper 14.

  The soft soil 4 introduced into the soft soil supply hopper 14 is cut out by a predetermined amount, is introduced into the uppermost belt conveyor 2, and is transported on the belt conveyor 2 in a leveled state.

  Then, the steelmaking slag 5 is added from the slag supply means 6 at a predetermined ratio to the fixed amount of soft soil 4 to be transferred. That is, the steelmaking slag 5 is cut into a certain amount by a feeder, and is sequentially transferred onto the belt conveyor 2 by the slag supply belt conveyor 16 and added to the soft soil 4 so as to form a layer at a predetermined ratio.

  Then, while the soft soil 4 to which the steelmaking slag 5 is added is transferred by the belt conveyors 2, 2..., The drop mixing operation is repeated for each connection between the belt conveyors 2, 2. Slag 5 and soft soil 4 are mixed.

  As shown in FIGS. 2 and 3, the drop mixing work is performed by dropping the soft soil 4 to which the steelmaking slag 5 is added from the discharge side end 2 b of the belt conveyors 2, 2. The soft soil 4 to which the steelmaking slag 5 that has undergone the collision is added while being collided with the mixing repellents 20, 20 placed in this manner, is introduced into the input side end 2 a of the downstream belt conveyors 2, 2. By doing.

  As a result, the mixing effect utilizing the energy at the time of dropping, the mixing action by the intrusion of the steelmaking slag 5 into the soft earth 4 due to the impact when colliding with the mixing repellent body 20, and the soft earth 4 and the steelmaking slag 5 are mixed. The soft soil 4 and the steelmaking slag 5 are mixed by the mixing action by the repulsive force received from the repelling body 20.

  Then, mixing is promoted for each connection between the belt conveyors 2, 2..., And calcia-modified soil 7 in which steelmaking slag 5 is mixed with soft soil 4 at a predetermined ratio is generated. The calcia-modified soil 7 is discharged from the transfer means 3 to the landfill A.

  As shown in FIG. 2, when the so-called shoulder flow method is used as the method for placing the calcia modified soil 7 in the landfill A, the shoulder shoulder inclined in the discharge direction on the ground portion of the discharge destination as shown in FIG. A surface (slope) 30 is formed so that the discharge side end 2b of the most downstream belt conveyors 2, 2... Is higher than the discharge destination ground by a predetermined drop height H (collision distance D). Install in. Then, the calcia-modified soil 7 is placed in the landfill A while performing the final drop mixing operation with the shoulder surface 30 as the collision surface portion 21 of the mixing repellent body.

  In the steelmaking slag mixing method for soft soil configured in this way, the soft soil 4 is adjusted to a moisture content suitable for mixing (1.2 to 1.6 times the liquid limit wL), and the soft soil 4 is moderate. By providing the viscosity and fluidity, as shown in FIG. 4 (b), when the steelmaking slag 5 collides with the repelling body 20 for mixing, the steelmaking slag 5 sinks into the soft earth 4 due to the impact, and the soft earth 4 and the steelmaking slag. The steelmaking slag 5 that repels the repellent 20 for mixing and stays and repels stays in the soft soil 4 without scattering due to the viscosity of the soft soil 4, and the soft soil 4 and the steelmaking slag 5 are preferable. To be mixed.

  Further, the number of collisions greatly affects the kneading effect due to the sinking and repulsion when colliding with the mixing repelling body 20, and the number of collisions, that is, the state of mixing for each connection between the belt conveyors 2, 2,. When improved and discharged to a transfer destination such as landfill A, calcia-modified soil 7 having excellent quality is generated.

  On the other hand, when the moisture content of the soft soil 4 is low (the water content ratio is less than 1.2 times the liquid limit), the soft soil 4 has a certain hardness and low fluidity. As shown in (a), the steelmaking slag 5 is difficult to sink into the soft soil 4 when colliding with the mixing repellent body 20, and the impact at the time of collision is transmitted to the steelmaking slag 5 through the soft soil 4, Due to the impact, part of the steelmaking slag 5 is bounced and scattered, and a suitable mixed state cannot be obtained.

  Further, when the moisture content of the soft soil 4 is high (the water content ratio is 1.6 times or more of the liquid limit), the strength of the soft soil 4 itself is insufficient as shown in FIG. Furthermore, since the viscosity is low and the fluidity is high, the rebound coefficient of the steelmaking slag 5 with respect to the mixing repellent body 20 is higher than the restitution coefficient of the soft soil 4 with respect to the mixing repellent body 20, so At the time of collision, the steelmaking slag 5 does not stay in the soft soil 4 due to the impact and repulsion, and the soft soil 4 and the steelmaking slag 5 are separated, so that a suitable mixed state cannot be obtained.

  Further, in the steelmaking slag mixing method for the soft soil configured as described above, every time the belt conveyors 2, 2. By performing, the soft soil 4 and the steelmaking slag 5 are sufficiently mixed, and calcia-modified soil can be produced in a large amount and at low cost in a series of transfer operations.

  Therefore, a stirring device such as a mechanical mixer for forcibly mixing the soft soil 4 and the steelmaking slag 5 is not required, and the installation can be suppressed at a low cost.

  Further, in the method of the present invention, since the water is not added to the soft soil 4 to which the steelmaking slag 5 is added during the transfer, the shaft mixing water is added in the process of pneumatic feeding. If soft soil having the same water content is used, modified soil 7 having high strength is generated.

  Furthermore, in utilizing the fall energy, the drop mixing operation is repeated for each transfer between the belt conveyors, so that the method of the present invention uses a tall tower-shaped kneading apparatus as described above. Without being able to mix soft soil and steelmaking slag, construction is possible regardless of the installation location.

  In the above-described embodiment, an example in which a fleet including a reclaimer ship 10 and a plurality of floating conveyors 11, 11... Is used as the transfer unit 3 is described. For example, it may be configured with a plurality of belt conveyors 2, 2... Installed on the ground, and a fleet composed of a reclaimer ship 10 and a plurality of floating conveyors 11, 11. The belt conveyors 2, 2... May be combined.

  Moreover, although the above-mentioned Example demonstrated the example which added the steelmaking slag 5 to the soft soil 4 which flows on the belt conveyor 2 using the belt conveyor 16 for slag supply, steelmaking slag is added to a soft soil. A means is not limited to the above-mentioned Example, For example, the steel-making slag 5 cut out for every fixed amount is transferred on the belt conveyor 2, and it cut out for every fixed amount on the steel-making slag 5 which flows on the said belt conveyor 2 The soft soil 4 may be put in, and the steelmaking slag 5 may be added to the soft soil 4 at a predetermined ratio.

  Next, in the steelmaking slag mixing method for soft soil according to the present invention, a reference experiment for verifying the influence of the moisture content of the soft soil 4 and the number of collisions with the mixing repellent 20 on the quality of the calcia-modified soil 7 will be described. . In addition, the same code | symbol is attached | subjected and demonstrated to the structure similar to the above-mentioned Example.

  In this experiment, a test piece formed by adding steelmaking slag 5 to soft soil 4 having a different water content ratio at a predetermined ratio (25 vol% in this experiment) is separated by a steel plate (mixing repulsion) with a collision distance D of 1 m in height. The body 20) is dropped and collided to perform a drop mixing operation, and the uniaxial compressive strength of the material of the calcia-modified soil 7 produced on the 28th day is measured, and the soft soil 4 and the steelmaking are visually observed. The mixed state with the slag 5 was evaluated. In addition, even when the number of collisions with the mixing repellent 20 is changed, the uniaxial compressive strength of the material of the calcia-modified soil 7 produced on the 28th day is measured, and the mixed state is evaluated by the strength and visual observation. did.

In this experiment, the reference strength is set such that the uniaxial compressive strength is 40 kN / square meter or more, and this strength is used as a reference for evaluation.
The results are shown in Table 1.

  When the moisture content of the soft soil 4 is low (1.0 times the liquid limit), the average strength is lower than the reference strength at one collision, and the visual confirmation shows that as shown in FIG. It was confirmed that the steelmaking slag 5 remained on the soft soil 4 and was not sufficiently mixed. Moreover, although average intensity | strength increased with the increase in the frequency | count of a collision, mixing was inadequate by visual confirmation.

  When the moisture content of the soft soil 4 is high (1.8 times the liquid limit), the average strength is lower than the reference strength at all the number of collisions, and as shown in FIG. Thus, it was confirmed that the steelmaking slag 5 was separated from the soft soil 4 and scattered.

  On the other hand, when the moisture content of the soft soil 4 is 1.2 and 1.6 times the liquid limit, the average strength exceeds the reference strength, that is, 40 kN / square meter, regardless of the number of collisions. It was confirmed that the steelmaking slag 5 was uniformly mixed in the soft soil 4. In addition, the average intensity increased with an increase in the number of collisions, and the intensity variation between samples decreased.

  From this, in the mixing of the soft soil 4 and the steelmaking slag 5 of the present invention, the water content ratio of the soft soil 4 is adjusted so that the soft soil 4 has a proper viscosity and fluidity. It was confirmed that a suitable mixed state could be obtained by adjusting the water content ratio of the soil 4 to 1.2 to 1.6 times the liquid limit.

  In addition, in the mixing of the soft soil 4 and the steelmaking slag 5 of the present invention, it was confirmed that the calcia-modified soil 7 having a stable strength as well as the strength was increased by increasing the number of collisions.

  Next, reference experiments for verifying the influence of the collision distance D on the quality of the calcia modified soil 7 in the steelmaking slag mixing method for soft soil according to the present invention will be described. In addition, the same code | symbol is attached | subjected and demonstrated to the structure similar to the above-mentioned Example.

  In this experiment, steelmaking slag 5 was added to soft soil 4 whose water content ratio was adjusted to 1.4 times the liquid limit at a predetermined ratio (25 vol% in this experiment), and the steel plate ( The drop mixing work to drop and collide with the mixing repellent 20) is performed three times, and the uniaxial compressive strength of the calcia-modified soil 7 produced thereby is measured on the 28th day of the material age. The mixed state of the soil 4 and the steelmaking slag 5 was evaluated.

  In this experiment as well, the standard strength is set such that the uniaxial compressive strength is 40 kN / square meter or more, and this strength is used for the evaluation.

  The result is shown in FIG.

  When the collision distance D shown in FIG. 5B was 1 m, although all samples exceeded the reference intensity, the intensity distribution of each sample varied.

  On the other hand, when the collision distance D shown in FIG. 5A is 2 m, all the samples exceed the reference strength (40 kN / square meter) and the collision distance D shown in FIG. 5B is 1 m. In comparison, the calcia-modified soil of stable quality was produced with less variation in strength.

  From this, it was confirmed that the mixing effect tends to increase as the collision distance D increases.

A Landfill 1 Mixing device 2 Belt conveyor 3 Transfer means 4 Soft soil 5 Steelmaking slag 6 Slag supply means 7 Calcia modified soil 10 Uplift (reclaimer ship)
DESCRIPTION OF SYMBOLS 11 Floating conveyor 12 Backhoe 13 Soil carrier 14 Soft soil supply hopper 15 Hopper 16 Slag supply belt conveyor 20 Rebound 21 for mixing Colliding surface part 22 Mixing promotion means 23 Fixed frame

Claims (2)

In the steelmaking slag mixing method for soft soil, the steelmaking slag is added at a predetermined ratio to a certain amount of soft soil, and the steelmaking slag and soft soil are mixed.
A transfer means having a plurality of belt conveyors installed so that the discharge side end of the upstream belt conveyor is higher than the input side end of the downstream belt conveyor by a predetermined drop height; and the transfer A moisture content adjusting means for adjusting the moisture content ratio of the soft soil introduced into the means, a slag supply means for adding steelmaking slag at a predetermined ratio to a certain amount of soft soil upstream of the transfer means, and each belt conveyor A mixing device comprising one or a plurality of mixing repelling members disposed at a predetermined collision distance below the discharge side end of the mixing side,
In addition, a method in which the discharge side end portion of the most downstream belt conveyor is set so as to be higher than the discharge destination ground by the predetermined fall height, and is inclined to the discharge destination ground portion in the discharge direction. A shoulder surface is formed, and the shoulder surface is used as a collision surface portion of the mixing repellent,
After adjusting the water content ratio of the soft soil so as to have an appropriate viscosity and fluidity by the water content ratio adjusting means, and throwing it into the transfer means,
Add steelmaking slag at a predetermined ratio from the slag supply means to the soft soil upstream of the transfer means,
After that, while transferring the soft soil added with the steelmaking slag toward the downstream side by each belt conveyor,
The soft soil added with the steelmaking slag is dropped from the discharge side end of the belt conveyor to collide with the repelling member for mixing, and the soft soil added with the steelmaking slag after the collision is the downstream belt. A steelmaking slag mixing method for soft soil, characterized in that the drop mixing work input to the input end of the conveyor is repeated for each connection between the belt conveyors, and the steelmaking slag and soft soil are mixed.   2. The steelmaking slag mixing method for soft soil according to claim 1, wherein the water content ratio having the appropriate viscosity and fluidity is 1.2 to 1.6 times the liquid limit.

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