JPH0321717A - Surface ground improvement work - Google Patents

Abstract

PURPOSE:To prevent splashing of a solidifying agent to eliminate ill effects on the surroundings by sprinkling an emulsified material or a suspended substance in which the solidifying agent is mixed with water on the surface layer of a weak ground, and mixing the surface of the ground with the emulsified material by a stabilizer, etc. CONSTITUTION:A solidifying agent such as cement, lime, etc., is mixed with water to obtain an emulsified material or a suspended substance. The liquid- solidifying agent 1 is sprinkled on the surface layer of a weak ground by a sprinkler-car 3, and then subsoil and the solidifying agent are mixed by a stabilizer 2. In this way, the surface layer is solidified to improve bearing capacity of the ground. Splashing of the solidifying agent during sprinkling the solidifying agent can thus be prevented.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a surface soil improvement method.

[Prior Art] Due to the dramatic increase in traffic volume in recent years, new roads are being built and existing roads are being extensively renovated.

Particularly recently, due to the increase in the amount of reclaimed land and the rising cost of land, there has been an increase in the number of construction projects being carried out in areas with poor ground. In such areas, ground improvement is essential.

In particular, roadbeds and roadbeds are parts that support traffic loads, and in paving work on soft ground areas, improvement of these parts is required.

There are broadly three types of surface ground improvement methods:

■ Replacement method A construction method in which the portion equivalent to the subgrade soil is replaced with high-quality soil.

■ Stable treatment method A construction method in which a hardening agent such as cement or lime is spread on the surface of soft subgrade soil, and then the subgrade soil and hardening agent are mixed to improve the bearing capacity of the subgrade.

■ Sand isoche method A construction method in which a layer of sand is placed on a soft roadbed, a layer of poorly mixed concrete or cement stabilized is placed on top of that, and paving is performed on top of this.

Traditionally, the replacement method was the mainstream, but it has become increasingly difficult to obtain high-quality soil, and transporting it tends to and inevitably causes social problems such as traffic pollution. In order to dispose of the remaining soil, it must be transported and it is difficult to secure a disposal site, so it is gradually being avoided.

In addition, the sand inch method requires a long construction period and is likely to be more expensive than any other method, and also has the disadvantage of producing residual soil, although the amount is not as much as in the case of the replacement method. ing.

Therefore, the stable treatment method will continue to be the main method in the future because it is preferable in terms of construction period, cost, and disposal of leftover soil.

This method requires the solidification agent to be thoroughly mixed with the soil, so it is usually mixed with a stabilizer.

FIG. 4 shows an example of a conventional road mixing type stabilizer 51. This example employs a caterpillar 52 drive system. During work, the rotor 53 is lowered together with the rotor hood 54, the lower surface of the rotor hood 54 is set to the ground line, and the height of the rotor 53 is then adjusted so that the digging III depth of the rotor 53 is a predetermined value. . And, before passing through this stabilizer,
Sprinkle powder solidifying agent. It passes through it while rotating a shank 55 provided on the rotor 53. The rotation of the shank crushes the soil clod and mixes the solidifying agent.

In the present invention, the structure and performance of the stabilizer are not particularly limited and may be general ones, and the above-mentioned stabilizer is one example thereof.

[Problems to be Solved by the Invention] However, in the conventional method, since the solidifying agent is a powder, the powder scatters during mixing. This is because it is necessary to stir the powder and soil in order to mix them sufficiently.

Even if mixing with a shank or the like is carried out in a hood, the solidifying agent on the pond will be rolled up by caterpillars or tires and will naturally scatter. In addition, since it is a powder, it will be blown away by wind and other factors when it is being sprayed, and a considerable amount will be blown away when it is handled. This scattering of the solidifying agent has a negative impact on local residents. That is, they not only stain the room by adhering to the laundry or entering the room, but also become troublesome to clean if they solidify.

In addition, in areas near fields, etc., it may be scattered onto crops, and it may not be possible to wash or remove it, resulting in a major blow.

Furthermore, if there is a construction site or a paint factory nearby, the scattered powder solidifying agent may adhere to objects that are not yet cured or dried, causing contamination. In such a case, the actual problem is that the work cannot be done or the work has to be done at a very low efficiency, resulting in a significant loss.

In order to eliminate the drawbacks of powder solidifying agents as mentioned above,
Recently, solidifying agents made into lumps have also been devised and commercially available. Since it is compacted to the size of a soybean, it can greatly reduce scattering during handling and spraying. however,
After the spraying, the caterpillar and tires pass over it, so
Since the powder is designed to collapse into powder in order to improve mixing, it is impossible to prevent the powder from being rolled up by a caterpillar or the like as it passes. Furthermore, even during mixing, scattering cannot be completely prevented.

Therefore, in this industry, there has long been a demand for a pouring method that does not scatter the solidifying agent.

[Means for solving the problem] In view of the current situation, the present inventor has perfected the method of the present invention as a result of intensive research, and its feature is that a solidifying agent is applied to the surface layer of soft ground. The point is to disperse and mix the emulsion or suspension of

Here, the soft ground is the ground that should be improved, and does not necessarily have to be soft.

The surface layer usually refers to the area about 100 cm from the surface of the ground.

The solidification agent may be any substance as long as it improves the ground by mixing with soil. Usually, it is Bortland cement, cement solidifying agent, lime, etc. An emulsion is a product obtained by mixing a solidifying agent with water and emulsifying it. Similarly, a suspension is a suspension of a solidifying agent. The mixing ratio of water and solidifying agent may be appropriately selected depending on the ground to be improved, the required strength, ease of pumping, etc., and is not particularly limited.

However, according to the inventor's experiments, a N ratio of about 1:1 was suitable.

Any method may be used to mix the solidification agent and soil. For example, you may use something like a yunbo or a backhoe. However, it goes without saying that using a stabilizer is the most effective.

Regarding the relationship between spraying and mixing of the solidifying agent, the spraying may be performed before passing through the stabilizer, but the spraying and mixing may be performed simultaneously. One possible method for this is to provide the stabilizer with a spray nozzle for the liquid solidifying agent. In this method, there are two methods: one in which a tank for the liquid solidification agent is provided on the stabilizer, and the other in which a separate tank and pump are provided, which are connected to the stabilizer with a hose and connected to the spray nozzle.

With the system where the tank is installed on the stabilizer, there are no problems with hoses, etc., and the stabilizer can be moved freely.
However, the capacity of the tank is limited. In addition, the hose-supplied type does not have any problem in terms of capacity, but it is difficult to move.

The position of the solidifying agent injection nozzle in the stabilizer is not limited as long as it is in front of the mixing shank. However, it is preferable to install it above the shank in the hood. In this way, since the spraying itself is dispersed, it is possible to prevent the solidifying agent from being unevenly distributed in one location. A pump is used to transport the liquid solidifying agent. The discharge pressure of the pump may be appropriately selected depending on the viscosity of the liquid solidifying agent. [Embodiments] The present invention will be explained in more detail below based on embodiments shown in the drawings.

FIG. 1 shows an example in which an emulsion 1 of a solidifying agent according to the present invention is spread on the ground and then mixed with an on-road mixing stabilizer 2. The liquid solidifying material is sprayed in front of the stabilizer 1 by a sprayer 3. In this method, a conventional stabilizer 1 can be used, and the spreader 3 can be a conventional water sprayer. In addition, it is also possible to simply make a hole in the bottom of a container such as a drum and hang it up using a jumbo or the like for spraying.

The amount of liquid solidifying agent used in this example was determined as follows. First, the weight of the powder solidifying agent required per 1 rrr of ground is determined.

l X0.45X1.5 X0.07X1000=47
．． 3kg/n? l:lrI? (Unit area) 0.45: Mixing depth from the ground surface (m) 1.5: Dry density of improved ground (ton/po) 0.07 2 Mixing ratio of powder solidifying agent (kg/kg) This is: This is determined experimentally based on the required strength of the ground.

1000: Unit conversion factor (kg/ton) Also, the mixing ratio of solidifying agent water and cement is I:I in terms of weight ratio, which is 1.3n per 1 ton of solidifying agent. Met. Therefore, the required amount of liquid solidifying agent per 1rrl of earth is 47.3x 1.3-61.54! /nf tofLru.

Therefore, it is sufficient to spray and mix 61.5 J per liter of ground.

In actual experiments with this amount, very good results were obtained. That is, there was no scattering of the solidifying agent at all, and the ground itself was not made of water, making it difficult for the stabilizer to run.

FIG. 2 shows that the stabilizer 2 is provided with a tank 4 for storing the liquid solidifying agent 1, and the liquid solidifying agent is removed from the nozzle 7 provided in the lid 6 of the stabilizer 2 by means of a pump 5 similarly provided in the stabilizer. This shows a type of stabilizer that spouts 1. Further, the nozzle 7 extends downward from a collecting pipe 8 provided above the hood 6. In this method, the liquid solidifying agent is sprayed on a rotating shank, so that it can be sprayed uniformly without bias.

FIG. 3 is a schematic cross-sectional view of the hood 6 of the example shown in FIG. 2. It can be seen that piping is connected from the upper collecting pipe 8 to the lower nozzle 7. It can also be seen that a liquid solidifying agent is sprayed onto the rotor. In this case, the spraying of the solidifying agent and the mixing by the stabilizer are almost simultaneous, so the relationship between the amount of spraying and the running speed becomes an issue. The inventor's experiment was conducted as follows. If the bomb discharge rate is 200j/shin and the stabilizer rotor width is 2m, then 200 +61.5+ 2 =1.62m/s+in. Therefore, the running speed of the stabilizer is 1.62
It is sufficient to fix it to m/sin. To fix the speed, simply look at the tachometer that displays the rotation of the hydraulic motor or subrocket. In this example, since the solidifying agent is sprayed and mixed at the same time, the work is simple and a separate sprayer is not required.

In order to further automate the process, it is also possible to detect the speed of the stabilizer (the number of revolutions of a sprocket, etc.) and control the discharge amount of the liquid solidifying agent using a control valve accordingly. If such a control method is adopted, the driver of the stabilizer can:
All you have to do is run completely freely, and the work is very easy.

In addition, although a separate power source may be used for the discharge pump motor, a hydraulic motor for the stabilizer may also be used. [Effects of the Invention] As explained in detail above, according to the method according to the present invention,
Since no powder solidifying agent is used, there is no scattering of the solidifying agent and there is no negative impact on the surrounding environment. Further, if the method involves simultaneously spraying and mixing the solidifying agent, the construction time can be greatly reduced.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of implementation of the present invention, and FIG.
The figures are side views showing other embodiments, FIG. 3 is a schematic sectional view, and FIG. 4 is a side view showing a conventional example. ...Liquid solidifying agent...Stabilizer...Water sprayer...Tank...Pump...Hood...Nozzle...Collecting pipe-C

Claims (1)

[Claims] 1. A surface soil improvement method characterized by spraying and mixing an emulsion or suspension of a solidifying agent on the surface layer of soft ground. 2. The surface soil improvement method according to claim 1, wherein the mixing is performed by a stabilizer.