JPH0376981B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for crushing brittle objects with a static crushing agent.

In recent years, static crushing agents have been increasingly used instead of gunpowder when crushing brittle objects such as rocks and concrete. This static crushing agent uses the pressure generated by the increase in volume when quicklime hydrates, and it is made by drilling holes in a brittle object and adding water to the static crushing agent in the holes to create a slurry. By injecting static crushing agent into a water-permeable bag and making it into a capsule, immersing it in water and filling it into the pores, a hydration reaction occurs in the pores, resulting in an increase in volume. This method statically crushes brittle objects using the applied pressure.

Conventionally, the size of a hole drilled into a brittle object is usually about 30 to 80 mm in diameter and 2000 mm in depth. However, when the brittle object is large, a very large number of holes of this size are required to be drilled. Therefore, the drilling work and the injection and filling work of the static crushing agent require a lot of manpower and time, making it impossible to crush efficiently. Therefore, the hole size was set to 150 mm in diameter.
There has been a demand for more efficient crushing by increasing the depth to 3 m or more and reducing the number of holes.

However, when the pore size is increased, various technical difficulties are encountered unlike when the pore size is small, and conventional static crushing agents cannot be used as they are. The biggest problem is that as the amount of crushing agent used per hole increases, the crushing agent reacts with water and generates more heat, and the heat of hydration accumulates in the hole, causing the temperature to suddenly rise to 100%. ℃ or higher. This temperature rise causes the free water present in the pores to evaporate, causing rapid volume expansion and ejecting the crushing agent in the pores, a so-called gun phenomenon. Therefore, not only is it impossible to crush brittle objects, but it is also extremely dangerous for the people working on it. In order to prevent this gun phenomenon from occurring, methods of adding a reaction retardant to the static crushing agent or adding aggregate (crushed stone) have been considered, but the former simply delays the reaction start time. Since the reaction itself was not suppressed, the time at which the gunshot phenomenon occurred was simply delayed, and no solution was reached. The latter is a recently devised method that uses crushed stone mixed with a static crushing agent. When using a crushing agent in a large hole, this method simply dilutes the static crushing agent by increasing the amount of crushed stone to an extent that does not cause the gunshot phenomenon, which causes cracks in the brittle object and then removes the cracks. The high expansion pressure required to develop and destroy brittle objects cannot be obtained, and the disadvantage is that the brittle objects cannot be completely destroyed. Furthermore, it was difficult to obtain stable performance because the crushing agent and the crushed stone were easily separated.

The present invention improves the conventional method of crushing using static crushing agents and provides a method that is useful even for large holes. The gist is a method of filling the pores of a brittle object with a static crushing agent to crush it, in which the hydration reaction of the static crushing agent is carried out in the presence of a porous material.

The porous material used in the present invention can be organic or inorganic as long as it has internally communicating pores and is water absorbing. Specifically, natural lightweight aggregates and artificial lightweight aggregates, such as "Athanolite" manufactured by Nippon Cement Co., Ltd., "Mesalite" manufactured by Mitsui Kinzoku Mining Co., Ltd., "Ube Light Bone" manufactured by Ube Industries, Ltd. Sumitomo Metal Mining Co., Ltd.
"Bilton" manufactured by Mitsubishi Mining Cement Co., Ltd. and "Sailite" manufactured by Mitsubishi Mining Cement Co., Ltd. are suitable. In addition, lightweight foamed concrete pieces, diatomaceous earth, etc. can also be used.

The specific gravity of the porous material used in the present invention after water absorption is, for example, about 1.6 for the artificial lightweight aggregate "Athanolite", which is approximately the same as the specific gravity of the static crushing agent slurry, 1.5 to 1.7. No separation occurs even when a slurry is made using Asanolite and a static crushing agent. On the other hand, the specific gravity of crushed stone after water absorption is as high as 2.6, so it tends to separate when made into a slurry.

In the method of the present invention, water is added to a static crushing agent in which porous material is mixed in advance, and the slurry is filled into the pores, or the porous material is first filled into the pores, and then Methods such as filling a slurry of a static crushing agent, or using a static crushing agent containing porous material packed into a water-permeable capsule can be adopted, but the following methods are applicable when using the slurry as a slurry. state

When using porous materials, the surface should be dry and saturated,
In other words, a porous material is immersed in water, sufficiently absorbed, and used without water on its surface.

A slurry is prepared from this porous material, a static crushing agent described below, and water. At that time, no difference in effect was observed even if the order of mixing was arbitrarily performed. For example, a porous material and a static crushing agent are mixed and then water is added to form a slurry, or a static crushing agent and water are made into a slurry, and then a porous material is added and mixed to form the required slurry. You can also do it.

If the slurry thus obtained is injected into holes previously drilled in a brittle object, it will harden over time, generate expansion pressure, and lead to fracture. The reason for this is not clear, but the water in the pores of the porous material moves to the surrounding hardened material (matrix) of the static crushing agent via capillaries, and the hydration reaction of the hardened material is stimulated. It is presumed that because the expansion is accelerated further, albeit gradually, compared to the previous case, high expansion pressure continues to be generated, thereby making it possible to completely crush the brittle object. Furthermore, since the porous material that has absorbed water has a large heat capacity, it absorbs the heat of reaction of the static crushing agent with water, so it is thought that the gunshot phenomenon does not occur.

The higher the water absorption rate of the porous material, the better, but one that is at least 5% (24 hour water absorption) can be used.

Furthermore, the mixing ratio of the porous material and the static crushing agent varies depending on the temperature of the brittle object when crushing, the pore diameter of the static crushing agent filling hole, the activity of the static crushing agent, etc. The ratio should be 5 to 90% by volume, and the mixing ratio of the static crushing agent should be 95 to 10% by volume. Within this blending ratio range,
If the gun phenomenon is likely to occur, that is, if the temperature of the brittle object is high, the pore diameter of the static crushing agent filling hole is large, or the static crushing agent is highly active, porous material can be used within the above blending ratio. It is better to increase the mixing ratio of materials.

Next, we combined the present invention with a porous material and the conventional method using crushed stone with a large pore size (for example, 150 mm in diameter).
Comparing cases where the porous material is used in the same volume, the final expansion pressure is higher when the porous material is used.

In the method using crushed stone, the expansion pressure almost ends after 8 hours after mixing with water, whereas in the case of the present invention, which uses a porous material, the expansion pressure continues to increase even after 12 hours. . As a result, crushing can be more complete.

In the conventional method, the gunshot effect cannot be prevented unless the blending ratio of crushed stone is at least 25% by volume, whereas if a porous material is used, the gunshot effect can be prevented by adding 10% or more by volume.

Compared to the method of mixing crushed stone, porous materials are less likely to cause material separation in the slurry, so stable performance can be obtained.

There are differences such as

Next, as the static crushing agent used in the present invention, one that generates expansion pressure through a hydration reaction, such as a commercially available static crushing agent, can be used. Commercially available static crushing agents include, for example, ``Calmite'' manufactured by Nippon Cement Co., Ltd. ``Blystar'' manufactured by Onoda Cement Co., Ltd. ``S-Mite'' manufactured by Sumitomo Cement Co., Ltd. ``CRS Splitter'' manufactured by Yoshizawa Lime Industry Co., Ltd. "Denka Chemiax" manufactured by Denki Kagaku Kogyo Co., Ltd. "Rock Punch" manufactured by Mitsubishi Mining Cement Co., Ltd. "Ubemite" manufactured by Ube Industries, Ltd., etc.

Water is added to the porous material and static crushing agent described above to form a slurry, and conventional equipment can be used for addition, mixing, and filling methods. For example, concrete mixers, agitator trucks,
This is a pump, etc.

If the resulting slurry is injected into a brittle object through pre-drilled holes and left to stand, it will harden and expand, leading to fracture.

The present invention is mainly effective in the case of large-diameter holes filled with crushing agent, but it can be applied to small-diameter holes of 80 mm or less in diameter, which is conventionally done by appropriately selecting the particle size of the porous material. It can also be used for

As explained above, the present invention exhibits a greater effect than the conventional method by using a porous material with a larger pore diameter than the conventionally used crushed stone. In other words, when a porous material and a static crushing agent are combined to form a slurry, and the slurry is injected into a large hole drilled in a brittle object to crush the object, the gun phenomenon does not occur and a sufficiently high expansion pressure is maintained. , it is possible to completely crush brittle objects.

Although we have described the case where the static crushing agent is used as a slurry, the same effect can also be obtained when using a static crushing agent containing a porous material packed in a water-permeable capsule. .

The present invention will be explained below using test examples and examples.

Test example 1 Asanolite, a commercially available artificial lightweight aggregate as a porous material (manufactured by Nippon Cement Co., Ltd., 24-hour water absorption rate 15.7)
%) was allowed to absorb water for 24 hours, and then the surface was wiped with a cloth to make the surface dry and saturated with water.

As a static crushing agent, commercially available "Calmite Bulk S Type" (manufactured by Nippon Cement Co., Ltd.) was used.

The above two materials were blended in various volume ratios and slurries were produced in the usual manner (water/calmite=
twenty three%). The resulting slurry was subjected to a crushing test using a steel pipe (inner diameter 170 mm) embedded in concrete in advance.
mm, depth 1000 mm), and the gunshot phenomenon and expansion pressure were observed and measured, and the results are shown in Figure 1.

The same method was used to replace the porous material with crushed stone, and the results are shown in the same figure. Note that the test temperature was 10°C.

As a result, it was found that when a porous material was blended, the gunshot phenomenon could be prevented with a small amount of blending, and the resulting expansion pressure was significantly higher than when crushed stone was blended.

Test example 2 The porous material was used as a static crushing agent, and the blending ratio was 30
The changes in inflation pressure over time were investigated in accordance with the procedure of Test Example 1, except that it was expressed as volume %. The results are shown in Figure 2.

As a result, when using porous materials, the development of expansion pressure is slightly suppressed in the initial stage compared to when using crushed stone, but even after 12 hours of age, the pressure continues to increase and the expansion is high. Since pressure is obtained, it is possible to completely crush even high-strength materials that cannot be crushed when mixed with crushed stone.

Example A field experiment was conducted on hard sandstone using the slurry of each material and composition used in Test Example 2.

150mm in diameter at the center of one side of 2m cubic hard sandstone.
Drill a hole with a depth of 1800 mm and inject the above slurry,
Observation after 24 hours showed that the method of the present invention using a porous material completely split the hard sandstone without causing a gunshot phenomenon, but when using crushed stone, cracks with a width of 0.2 mm and a length of 200 mm were observed. The fracture occurred only on both sides of the hole, indicating that the fracture was incomplete.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the mixing ratio of crushed stone or porous material and the 24-hour expansion pressure, and FIG. 2 is a graph showing the change in expansion pressure over time. The test temperature in both cases was 10°C.

Claims (1)

[Claims] 1. A method of crushing a brittle object by filling the pores of a brittle object with a static crushing agent, the method comprising performing a hydration reaction of the static crushing agent in the presence of a porous material.