JPH0617571B2 - Method for continuously mixing soil and soil conditioner and plant for implementing the method - Google Patents

Description

The present invention relates to a method for continuously mixing sediment and soil conditioner and a plant for carrying out this method.

The materials used for landfill and embankment are the main materials that make up the landfill and embankment, so their properties affect the difficulty of construction and the quality of the landfill and embankment after completion, and therefore they should be of the highest quality possible. It is desirable to select and use materials.

However, it is economically not so easy to select and use good quality materials.

In order to eliminate this drawback, it is practiced to mix the soil improvement material in advance with the collected soil as a material to make the landfill and the embankment. Various types of mixers are used for the production of landfills and embankments composed of this mixed material, for example, drum type continuous mixers for improved structural soils such as roadbeds. In terms of price, labor saving and automation, it is not suitable for continuous mixing of large amounts of soil.

The problem that forms the basis of the present invention is that the accuracy of the soil and soil improvement material is good, a large amount, and continuous mixing is possible, and in that case the generation of dust is suppressed as much as possible, in order to create a landfill and a bank. And a plant for carrying out this method.

This problem is in the method according to the present invention, first to spread the earth and sand on a belt conveyor that moves continuously for the purpose of making landfill, fill, and then to spread a soil improvement agent on the earth and sand layer. Repeated one or more times, scatter earth and sand on these alternating layers, transfer the layered product of alternating layers sandwiching the soil improvement material in the middle of the earth and sand layer thus formed, and damper chute for mixing The solution is achieved by abutting against and mixing and handing over to another belt conveyor.

Further, in another configuration of the present invention, when the mixed material is used for landfilling under water, the material molded in the mixing section is further sprayed with a liquid soil improvement agent such as a separation preventing agent. Is added.

Further, in the present invention, the parameters or blending amounts of the soil conditioner and the soil in the mixing process are controlled by the automatic control mechanism connected to the measuring device or the measuring device for them.

Further, in the present invention, the feature of the plant for carrying out the above-mentioned method is that between the supply conduit of one system or a plurality of systems for supplying the soil improvement material from the upper storage tank, the measuring device and the earth and sand feeder device. Soil improvement material supply unit consisting of arranged soil improvement material feeder device; hopper or stock pile, a plurality of earth and sand feeder devices arranged along the flow of the belt conveyor for continuously supplying earth and sand onto the belt conveyor, earth and sand A material consisting of a belt conveyor for transporting water, a water content measuring device for continuously measuring the water content ratio of soil and sand, and a transportation amount measuring device for continuously measuring the total supply amount of soil and soil improvement agent on the belt conveyor. Compounding section; and the material mixing section at each transfer section of the final belt conveyor and one or more intermediate belt conveyors. And a damper chute which transfers the layered products of alternating layers formed by the above, abuts against the damper chute, and delivers to the downstream mixing belt conveyor while mixing; a first mixing section; .

Furthermore, in the present invention, when the mixed material is used for landfilling under water, in order to further process the mixed material formed in the above mixing section, a liquid soil conditioner storage unit, It is equipped with a device for pumping the material, a device for continuously spraying the liquid soil improving agent in a spray form, and a damper chute for spreading the mixture of the earth and sand and the powder soil improving agent into a strip shape at the discharge portion of the belt conveyor.

By the above method and plant, it is possible to perform the conventional rough landfill or embankment preparation by sufficient mixing under an ideal blending amount, and to prepare the landfill soil or embankment. Is carried out in a continuous working mode, with the advantage that large quantities of soil can be produced in a very economical process.

As means for improving the mixed state, there are a method in which a plurality of feeders for earth and sand and a soil improvement material are used to form a sandwich of 5 layers or more, and a method in which a damper chute for mixing is installed in a plurality of places and mixing is repeated. However, it is desirable to select a combination in consideration of the properties of earth and sand and soil improvement materials, the transportation capacity of the plant, restrictions on the installation location, and the like.

Hereinafter, the present invention will be described in detail with reference to the embodiments illustrated in the accompanying drawings.

FIG. 1 schematically shows the simplest case of the plant according to the present invention, that is, the case of two sediment feeders and one mixing chute. First, as a work process sequence, the earth and sand stored in the hopper or the stock pile 1 which is partitioned from the belt conveyor 3 by the partition wall 20 is constantly measured by the first water content ratio measuring device 11 while the earth and sand feeder device is being measured. It is supplied onto the belt conveyor 3 by means of 2 so as to be laminated on the surface of the belt.

On the other hand, the soil-improving material is prepared in the form of powder and stored in the storage device 4, and from here, it is measured via the conduit 5 by the measuring device 12 for continuously measuring the supply amount of this soil-improving material. It is supplied to the improvement material feeder device 22 and is supplied so as to be laminated to a substantially uniform thickness on the previously supplied earth and sand device. Here, two material layers consisting of a sand layer and a soil improvement material layer are formed on the belt conveyor 3.

Then, similarly, the earth and sand stored in the hopper or the stock pile 1 are measured by the second water content ratio measuring device 11 ', and the earth and sand layer already formed on the belt conveyor 3 by the earth and sand feeder 2'-Soil quality It is provided to be similarly laminated on the modifier layer.

Here, on the belt conveyor 3, the earth and sand layer immediately above this belt conveyor, the soil improvement material layer on the layer surface of this earth and sand layer, and the earth and sand layer again laminated on this soil improvement material layer A material layer, that is, a sediment layer-a soil improvement material layer-a sediment layer is formed.

Next, the three-layer material soil layer is formed on the belt conveyor 3
Further, the transportation amount measuring device 13 continuously measures the transportation amounts of the earth and sand and the soil improvement material on the way. The soil layer compact leaves the belt conveyor 3 at the end of the belt conveyor 3, but at this time, it strikes a mixing damper chute 6 provided on the front side in the flow direction, and the mixing damper chute 6 causes the layer compact to be formed. Are separated and the three layers are mixed up and mixed. That is, the first mixing of the above materials is performed at this position. The effect of this shear mixing is achieved by the special construction of the mixing damper chute described below.

FIG. 2 shows a sectional view of a first embodiment of the mixing damper chute 6, and FIG. 3 shows a front view thereof. As is clear from FIG. 2, the mixing damper chute 6 is composed of a front plate body 30 which is orthogonal to the center line of the belt conveyor, and the material of the plate body 30 collides with the front plate body 30 and flows down. Two baffle plates 31, which are almost square when viewed from the side, are provided at approximately the center of 30, and a layered body consisting of a sediment layer-soil conditioner layer-sand layer collides with this baffle plate 31 and breaks into pieces. To be done. The plate body 30 is provided with guide side walls 32 inclined toward the center toward both sides of the lower end in the flow direction, and these guide side walls 32 are provided with folds toward the center toward the edges. There is. This guide sidewall 32
The outlet 33 of the plate body 30 partitioned by is tapered. The flowing material layer has a spiral behavior by rubbing against the baffle plate 31 of the plate body 30 and then colliding with the guide side wall 32 while rubbing them, and at this time, the layered body is completely fragmented and mixed. It

FIG. 4 shows a sectional view of the second embodiment of the mixing damper chute 6, and FIG. 5 shows a front view thereof. As is clear from these figures, the damper chute 6 according to this embodiment intersects at a shallow angle with a parabola drawn by a layered body whose bottom is discharged from the belt conveyor 3-soil improvement material layer-sand layer. It is formed of a bar 34 and an inclined side guide plate 35. The side guide plate 35 is tapered downward, that is, in the material flow direction. The material of the layered body composed of three layers, which are layered in the order of the sediment layer-the soil improvement material layer-the sediment layer and carried by the belt conveyor 3, is discharged from this belt conveyor and intersects with the above-mentioned bar 34 while falling. Then, the material is divided in parallel with the flow of the material, and when it slides down on both sides of each bar 34, the layers are separated and fractured and mixed.

The material shear-mixed by the damper chute 6 is further transferred by the belt conveyor 21 and directly supplied to the work site or stored.

Here, when the mixed material formed in the damper chute 6 of the mixing section C is used for underwater landfill such as landfill in the ocean, the mixed material is used by the belt conveyor 21.
Is transferred into the damper chute 10 provided in front of the discharge port of the belt conveyor 21. The damper chute 10 has a plane orthogonal to the center line of the belt conveyor 21, as shown in FIGS. 6 and 7,
It has vertical guide plates 36 rising from the plane on both sides of the lower part. Here, the material discharged from the conveyor 21 and colliding with the damper chute 10 spreads along the plane of the damper chute to form a thin, uniform curtain-shaped layer having the inner width of the vertical guide plates on both sides of the lower part of the damper chute. Liquid, and a liquid soil improvement material such as a separation inhibitor sent from the liquid soil improvement material storage unit 7 through the pressure-feeding device 8 in a plane direction orthogonal to the vertical flow of the curtain of earth and sand. Is sprayed and added via several measuring devices 14 (nozzle mechanism) 39 (see FIGS. 6 and 7).

Thereafter, the mixed earth and sand material is transported as soil as a finished material, or loaded on an appropriate transportation means.

The parameters or compounding amounts of the soil conditioner and the earth and sand processed in the mixing method and the mixing plant according to the present invention are set on the basis of the dry weight of the earth and sand, and the mixing amount setting reference value is input to the automatic control mechanism 15. The detection mechanism connected to this control mechanism 15 is
15-1,15-2,15-3,15-4,15-5,15-6 and 15-7 and the following measuring device and measuring device, that is, water content measurement for continuously measuring the water content of earth and sand Devices 11 and 11 ', weighing devices 12 and 14 for continuously measuring the amount of powdery soil improving agent supplied, and a transporting amount measuring device 13 for continuously measuring the amount of soil and soil improving agent transported on a belt conveyor. The plant operation / operation control is performed via the.

This control mode will be described based on the control block diagram shown in FIG.

In the reference value setting section D, reference values are set for the hourly transportation amount and shipping unit amount of earth and sand (natural state), the natural water content ratio of earth and sand, and the respective mixing ratios of the soil improvement material. The actual value according to the progress of plant operation is detected by the actual value detection unit E,
The detected actual value is given to the comparison / operation unit F, where the difference between this actual value and the reference value is compared and calculated by the comparison element and the operation element, and the difference value signal formed by this comparison / operation is The command / driving unit G is fed back to the measuring devices and weighing devices of the plant, and these measuring devices and weighing devices are controlled. In this case, the setting reference value, the detected value, the calculated value and the operating parameter based on these values are recorded in the recording unit H.

This control mechanism is constructed in a known manner and is not a feature of the present invention and therefore not described in detail.

As an example of the above control, the compounding amounts of the earth and sand and the soil conditioner will be specifically described below.

48 parts by weight of earth and sand supplied from the upstream side sand and sand feeder device, 4 parts by weight of soil improvement material supplied from the storage unit 4, and 48 parts by weight of earth and sand supplied from the downstream side sand and sand feeder device 2 ' Form a mixed material of layers. In some cases, 0.01 parts by weight of a fluid soil conditioner is added to the mixed material from the reservoir 7.

In this case, the water content ratio of the earth and sand loaded on the belt conveyor 3 is measured by the water content ratio measuring device 11 or 11 'provided at the outlet of the earth and sand supply stock pile or the hopper, and the control mechanism is used.
The dry weight of earth and sand can be obtained by the comparison / calculation element provided in 15. The mixing ratio of the soil improvement agent is given to the automatic control mechanism 15 as a reference value, and the soil improvement agent having a set amount relative to the dry weight of the earth and sand supplied to the belt conveyor 3 is instructed to the earth and sand feeder device 2. , The weighing device 12 continuously weighs. At this time, the supplied amount of soil and soil improvement material is measured by the above measuring device, input to the control mechanism 15 by an electric signal, compared and calculated, and fed back to each measuring device and measuring device to control the supplied amount to the set target value. To be done.

Examples The experiments described below were carried out in order to demonstrate the effects obtained by the mixing method according to the present invention and the plan therefor.

The experimental equipment consisted of three belt conveyors with a belt width of 350 mm and a belt speed of 100 m / min, which were arranged in series. On the most upstream belt conveyor No. 1 from the upstream side of the belt conveyor, the sand hopper No. 1 with feeder was installed. , No.2 was installed. A soil improvement material hopper with a feeder was installed between the two earth and sand hoppers.

No. of 3 belt conveyors 1, No. No. 2 belt conveyor is equipped with a damper chute for mixing. 3 A flat plate expansion damper chute is attached to the discharge part of the belt conveyor, and below that, two spray nozzles are provided on the front and back of the mixed material of earth and sand and soil improvement material that flow down in a belt shape from this flat plate expansion damper chute. A device for spraying a liquid soil conditioner was used.

No. The soil corresponding to 30 kg dry weight is continuously fed from No. 1 sand hopper onto No. 1 belt conveyor, and at the same time, 2.4 kg of soil improvement material is continuously formed on the sand layer. To supply. No. From the earth and sand hopper 2 above, the earth and sand and the soil improving agent are continuously supplied with a dry weight equivalent to 30 kg to cover the soil improving agent.

The mixed material to be supplied, transferred and discharged by this apparatus was deposited on the receiving box.

The soil used in the experiment was sandy soil, ordinary Portland cement was used as the soil conditioner, and the separation inhibitor dissolved in salt water was used as the liquid soil conditioner.

The blending ratio of each material is 4% (wt%) of ordinary Portland cement to 100 kg of dry earth and sand, and 100 mg of separation inhibitor.
And

Regarding the degree of mixing, the mixed material deposited in the receiving box was visually observed, the calcium content was measured, and the salt water ion concentration was measured.

In a normal damper chute that is not devised for mixing, uneven distribution of soil improvement material is clearly visible on the surface and cross section of the mixed material deposited in the receiving box, and there is no mixing effect.

In the case where the damper chute for mixing was used, uneven distribution of the soil improvement material was not visually recognized, and samples were taken from many points of the deposited material and the next test was performed.

The content of calcium contained in ordinary Portland cement of the soil conditioner in each sample was measured and converted into the content of the soil conditioner. For the separation preventing agent of the liquid soil conditioner, the chloride ion concentration in the dissolved salt water was measured and converted into the content of the separation preventing agent.

Measurement results 1. Soil conditioner (ordinary Portland cement) Supply mix ratio 4.0% Content in sample Average 3.8% (standard deviation 0.194 Coefficient of variation
0.1) 2. Liquid soil conditioner (separation inhibitor) Supply ratio 100mg / kg Content in sample Average 91mg / kg (standard deviation 34.2, coefficient of variation 0.37) From the above results, continuous improvement of soil improver by the plant according to the present invention. Mixing is possible.

In addition, the method according to the present invention is a method capable of preventing dust from scattering even during transportation of fine soil improvement agents.

[Brief description of drawings]

FIG. 1 is a schematic view of a mixing plant for soil and soil improving material according to the present invention, FIG. 2 is a sectional view of a first embodiment of a damper chute used according to the present invention, and FIG. 3 is a front view of FIG. Fig. 4, Fig. 4 is a sectional view of a second embodiment of the damper chute used according to the present invention, Fig. 5 is a front view of Fig. 4, and Fig. 6 is used for mixing a fluid soil conditioner. Fig. 7 is a sectional view of a damper chute, Fig. 7 is a front view of Fig. 6, and Fig. 8 is a block diagram of a control device for carrying out the method according to the present invention. The symbols in the figure are: 1 hopper or stock pile 2, 2 '... earth and sand feeder 3 ... belt conveyor 4 ... soil improvement material storage device 5 ... soil improvement material supply conduit 6 ... damper chute 7 ... Liquid soil conditioner storage device 8 …… Liquid soil conditioner pumping device 9 …… Spraying device 10 …… Damper chute 11, 11 ′ …… Soil water content ratio measuring device 12 …… Weighing device 13 …… Transportation weighing device 14… … Liquid soil conditioner measuring device 15 …… Control mechanism 15-1,15-2,15-3,15-4,15-5,15-6,15-7 …… Detection mechanism 22 …… Soil conditioner feeder apparatus

Claims (5)

[Claims] 1. A method for continuously mixing earth and sand and a soil conditioner, which comprises first spraying earth and sand on a continuously moving belt conveyor for the purpose of producing landfill and embankment,
Then repeating the application of the soil conditioner onto the earth and sand layers once or a plurality of times, and applying earth and sand onto these alternate layers,
In the middle of the earth and sand layer formed in this way, transfer the layered body of alternating layers scissoring the soil-improving material in a sandwich shape, contact the damper chute for mixing and deliver it to another belt conveyor while mixing. A method for continuously mixing sediment and soil improvement material. 2. When the mixed material is used for landfilling under water, a liquid soil improving agent is further added by spraying to the mixed material to continuously mix soil and soil improving agent. The method according to item 1. 3. The method according to claim 1 or 2, wherein the parameters of the soil conditioner and the soil and the mutual mixing amount are controlled by an automatic control mechanism connected to a measuring device or a measuring device for these. The method described in. 4. A plant for carrying out a method for continuously mixing soil and soil improvement agent, wherein one or more supply conduits (5.) for supplying soil improvement agent from a storage tank (4). ....), a weighing device (12 ....) and a soil improvement material feeder device (22, ...) placed between the sediment feeder device (2,2 '...) Material feeding section (A); Hopper or stock pile (1), Belt conveyor (3) for continuously feeding earth and sand onto the belt conveyor (3)
Multiple sediment feeders (2,
2 ′ ...), a belt conveyor (3) that carries sediment, and a moisture content measuring device (11, 1) that continuously measures the moisture content of sediment.
1 '...), and a transport amount measuring device (13) that continuously measures the total supply amount of earth and sand and soil improvement material on the belt conveyor.
A material blending section (B); and a final belt conveyor (21), one or more intermediate belt conveyors (3 ...) at each transit section formed by said material blending section (B). Alternating layered compacts are transferred, abutted against the mixing damper chute and delivered to the downstream belt conveyor while mixing and are mixed.
(6, ....) and a mixing section (C); which is a plant for continuously mixing sediment and soil conditioner. 5. The mixture (C) is a liquid soil improvement agent storage unit.
(7), a device (8) for pumping the liquid soil conditioner, a device (9) for continuously spraying the liquid soil conditioner in a spray form, and a device for discharging soil and powder soil conditioner at the discharge part of the belt conveyor. 5. The plant according to item 4, further comprising a damper chute (10) for expanding the mixture into a strip shape.