JP2007040095A - Method for improving compaction property of water-crushed slag layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which is excellent in forming a ground which has high supporting force by improving conventional technology and improving a compaction property of a water-crushed slag layer. <P>SOLUTION: In the method for improving the compaction property of the water-crushed slag layer, earth and sand of decomposed granite soil or the like is laid on a layer comprising a water-crushed slag of a blast-furnace water-crushed slag or the like to form a layer, and the superposed layer is pressed from upward direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for improving compaction when embankment, reclamation, backfilling, soil covering, and the like are performed using granulated slag.

  Granulated slag produced as a by-product from steelworks and metal smelting plants is used for embankment, reclamation, backfilling, and covering of ground and roadbeds. In this case, in order to increase the density at the site, generally, the upper portion (surface layer portion) of the granulated slag is compacted using a heavy machine such as a bulldozer or a tire roller.

  However, since granulated slag is a single particle size whose particle size curve is not smooth, even if it is compacted with heavy machinery, the granulated slag particles move to the side, so the compaction property is poor and is expressed by CBR value etc. There is a drawback that it is difficult to support. In addition, the surface layer portion of the granulated slag layer immediately after being compacted with heavy machinery has a low filling density, so that when the vehicle passes, wrinkles are generated, or footprints remain when people pass. In addition, there is a problem that flatness is difficult to be secured because the density of the surface layer portion such as the depression is easily depressed when pressed with a finger.

Blast-furnace granulated slag, which has hydraulic properties and hardens with time, is often used as granulated slag, but when blast-furnace granulated slag is used, it is approximately 15 cm inward from the surface of the slag layer. When the surface layer part of the layer comes into contact with air, it is carbonated to inhibit the hydration reaction. Therefore, there is also a problem that the granulated slag layer does not solidify without causing a change with time.
JP 2003-12363 A

  It is an object of the present invention to provide an excellent method for solving the above-described problems of the prior art, improving the compaction property of the granulated slag layer, and creating a ground having a high supporting force. It is a thing.

  The structure which makes the summary of this invention made | formed in order to solve the subject mentioned above is as follows.

  That is, the first invention is a method for improving the compaction property of a granulated slag layer, characterized in that earth and sand are laid on the upper part of the layer made of granulated slag to form a layer and pressed from above the polymerized layer. .

  The second invention is a method for improving compaction of a granulated slag layer in which a plurality of polymer layers composed of a granulated slag layer and a layer made of earth and sand are laid in the first invention. .

  The third invention is a method for improving compaction of a granulated slag layer, wherein the granulated slag is a blast furnace granulated slag in the first invention or the second invention.

  Furthermore, a fourth invention is a method for improving compaction of a granulated slag layer in which the earth and sand is masa in any of the first to third inventions.

  According to the present invention, since the compaction property of the granulated slag layer can be improved by a simple construction method, a ground having a high supporting force can be easily obtained. Moreover, in this invention, since the granulated slag byproduced in large quantities from a steelworks and a metal smelting factory is utilized, a construction cost can be lowered | hung and a useful effect is exhibited also from the surface of effective utilization of resources.

  The present inventors have solved the above-mentioned problems of the prior art, and have studied the use of earth and sand such as masa soil as a means for improving the compaction properties of embankments and grounds using granulated slag. It has been found that it is effective to cover the ground granulated slag with a thin layer of earth and sand such as muddy soil having a smooth particle size distribution on the upper surface of the granulated slag and having a high packing density. It was.

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

FIG. 1 and FIG. 2 show a schematic cross section of the ground during embankment or covering work. In FIG. 1, when embanking on the foundation ground 1, first, granulated slag is spread on the upper surface of the foundation ground 1. The granulated slag layer 2 having a constant layer thickness is formed. Next, a clay soil is spread on the upper part of the granulated slag layer 2 to form a clay soil layer 3 having a constant layer thickness. That is, the superposition | polymerization layer A which piled up the masa soil layer 3 and the granulated slag layer 2 up and down is formed. Thereafter, the surface layer portion of the polymerization layer A is rolled using a rolling machine or the like, and the entire region of the layer is pressed from above the polymerization layer A as indicated by an arrow F.
By performing the pressing operation in this way, the filling density of the clay 3 is increased, and the compaction property is improved. As a result, the supporting force of the ground is improved.

  FIG. 2 shows a schematic cross section when the second polymer layer A ′ is formed on the polymer layer A shown in FIG. 1, and after the pressing operation of the polymer layer A is completed in FIG. A granulated slag layer 2 ′ having a constant layer thickness is formed on the upper part of the polymerization A, and a rust soil layer 3 ′ having a constant layer thickness is further formed on the upper part of the granulated slag layer 2 ′. In this way, the polymerization layers A and A ′ composed of the granulated slag layer and the mass soil layer are formed. Thereafter, the surface layer portion of the polymer layer A ′ is rolled in the direction indicated by the arrow F from above by using a rolling machine or the like, not only the second polymer layer A ′ but also the first polymer layer A. The pressing force also acts. In this way, the polymerization layers A and A ′ become a ground having a high supporting force by improving the compaction property as a whole.

  As can be seen from the description of the above-described embodiment, masa soil plays an important role in the construction method according to the present invention in order to supplement the compaction property of the granulated slag used as the aggregate.

  On the other hand, granulated slag, which is aggregate, is a sand-like substance granulated by applying high-pressure water to high-temperature molten slag generated during the refining process of various metals and rapidly cooling it. It is a by-product generated in the smelting factory. As the granulated slag, there are various types such as blast furnace granulated slag, steelmaking granulated slag, alloyed iron granulated slag, copper refined granulated slag, and any of the granulated slag can be used. As preferred, blast furnace granulated slag is recommended.

  This granulated blast furnace slag has a maximum particle size of 10mm or less, contains abundant mineral components such as CaO, SiO2, Al2O3, and has relatively high strength, water permeability, water retention, hydraulic properties. Is excellent.

  In the present invention, when blast furnace granulated slag is used as the granulated slag, a mass layer is formed on the upper part of the blast furnace granulated slag layer, so that the surface portion of the blast furnace granulated slag layer is in contact with air. Blocked. Accordingly, the ground granulated blast furnace slag layer is not carbonated and the hydration reaction is not hindered, but the hydration reaction proceeds and hardens throughout the entire layer, thereby strengthening the support capacity of the granulated slag layer itself. It comes to have the advantageous characteristics of.

  Next, the embodiment described in FIG. 1 and FIG. 2 shows an example in which the polymerized layer composed of the granulated slag layer and the masa soil layer has one layer and two layers. It is not limited to two layers, and when the pressure receiving load on the embankment surface such as the ground and the roadbed and the landfill surface becomes large, it is natural that a multilayer structure having three or more polymerization layers is adopted.

  In order to clarify the excellent effects of the present invention, examples will be described below.

Example 1
In the laboratory test, the basic effect of the construction method according to the present invention was confirmed.
A granulated slag layer was formed by laying and leveling granulated blast furnace slag in the lower layer in a φ15 × 12.5 cm CBR mold. . Table 1 shows the combinations of the thicknesses of the Masa soil layer and the granulated slag layer. Five types of specimens M1 to M5 with different thicknesses of granulated slag layer and masa soil layer were compacted by the E-c method of JIS A1210, and the CBR value was measured by the design CBR test of JIS A1211. The CBR value is the average of the measurement results of 3 specimens per specimen number. The results are shown in Table 2 and FIG. FIG. 3 is a graph showing the CBR value of each specimen in comparison with the soil layer thickness.

From Table 2 and Fig. 3, when a polymerized layer is formed by polymerizing the masamite layer and the granulated slag layer under both the curing conditions in the air and underwater, the CBR value is proportional to the thickness of the masamite layer. You can see that it is rising.
(Example 2)
Next, the actual effect of the construction method of the present invention was confirmed by an on-site construction test.

As shown in Table 3, 4 ground 40m ² (10m x 4m) grounds were selected as test zones (locations) (A to D zones), and blast furnace granulated slag was 1m thick using a backhoe. And layered to form a layer. On this (surface), a subgrade ground was formed by covering and covering masa soil with a thickness of 0 cm (A section), 5 cm (B section), 10 cm (C section) and 15 cm (D section). The clay was spread and compacted using a macadam roller (12 t) 6 times.

 The CBR test result of the test body based on this construction test is shown in FIGS.

  FIG. 4 shows the CBR value of the roadbed ground surface of each work section measured immediately after construction, expressed as a ratio (CBR value of each work section / A work section CBR value) with the value of the A work section being 1, and FIG. When the decree is changed, that is, immediately after the construction, 3 months after the construction and 6 months after the construction, excavate the soil layer in each work area, and the granulated slag layer, the CBR value of each work area in the same way The value is represented by a ratio (CBR value of each work section / CBR value immediately after construction of the A work section).

  From Fig.4, in the case of subgrade ground (B, C and D section) where the masa soil layer is coated and polymerized on the granulated slag layer, the granulated slag single layer (A section) that does not cover the masa soil layer. It can be seen that the CBR value is increased in comparison.

  From the results of Fig. 5, in the case of granulated slag single layer (A zone), even if the material age increases, the CBR value does not change, but when the soil layer is polymerized (B, C and D) It is clearly recognized that the CBR value on the surface of the granulated slag layer increases as the age increases in any thickness of the soil layer. This is because the surface layer portion of the granulated slag layer is blocked from contact with air by the magma soil layer coated as described above, so that the hydration reaction is not hindered and cured sufficiently, This is because the supporting force of the slag layer is strengthened.

  As for the thickness of the masa layer, if the thickness is increased from the results of the above example, the compactness, that is, the supporting force of the ground will be improved. On the other hand, the cost increases due to the increase in the amount of masa soil used. Therefore, considering both surfaces, it is preferable to use a thickness of 3 to 20 cm, and a thickness of 7 to 15 cm is particularly preferable.

  In the embodiments and examples of the present invention, the case of using a particularly preferable mass as an example of earth and sand has been described. However, the present invention is not limited to this, and the case of applying other earth and sand is also not limited thereto. The object can be achieved.

The typical sectional view of the ground which shows the embodiment of the improved construction method concerning the present invention. The typical sectional view of the ground which shows other embodiments of the improved construction method concerning the present invention. The graph which shows the CBR value of the various test body in Example 1 of this invention. The graph which shows the CBR value (relative value) of the roadbed ground surface immediately after construction of each work area in Example 2 of this invention. The graph which shows the CBR value (relative value) of the granulated slag layer surface of each work area which excavated the masa layer in Example 2 of this invention.

Explanation of symbols

1: Basic ground
2, 2 ': Granulated slag layer
3, 3 ': Masa soil layer
A, A´: Polymerization layer
F: Pressing force

Claims (4)

A method for improving the compaction property of a granulated slag layer, characterized in that earth and sand are laid on the upper part of the layer composed of granulated slag to form a layer and pressed from above the polymerized layer. The compaction improvement method of the granulated slag layer according to claim 1, wherein a plurality of polymer layers composed of the granulated slag layer and a layer made of earth and sand are laid. The method for improving compaction of a granulated slag layer according to claim 1 or 2, wherein the granulated slag is blast furnace granulated slag. 4. The method for improving compaction of a granulated slag layer according to any one of claims 1 to 3, wherein the earth and sand is a mass.

Images