JP2003003514A - Method for mixing additive into sediment slurry in pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the amount of injection of an additive so as to allow a desired degree of cure to be obtained in accordance with variations in water content of sediment slurry in a method for mixing the additive in a carrier pipe, in which the additive is injected during movement of the sediment slurry in the carrier pipe. SOLUTION: Into a computer 28, there is pre-input a proper mixing ratio of the additive with respect to the water content of the sediment slurry conveyed through the carrier pipe 24 for pneumatically pumping the sediment slurry in which water is mixed into sediment; the water content of the sediment slurry is measured before the sediment slurry reaches an additive injector 27 in the carrier pipe 24; and the amount of the injection from the additive injector 27 is adjusted in accordance with the proper mixing ratio of the additive with respect to the water content pre-input into the computer 28.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, when an earth and sand slurry for landfill is mixed with an additive material mainly composed of a solidifying agent to form a landfill soil, the additive material is added when the earth and sand slurry is pneumatically fed. The present invention relates to a mixing method in an additive pipe for pouring earth and sand slurry.

[0002]

2. Description of the Related Art Conventionally, a slurry-like landfill sand is sent to a carrier pipe, and an additive material mainly containing a solidifying agent is injected while pneumatically feeding the inside of the carrier pipe, and is poured into a landfill site to be solidified. A mixing method in an additive pipe has been developed.

In this conventional mixing method in an additive material pipe, a slurry-like landfill earth and sand is divided into a large number of lump-shaped plugs sandwiched between air parts in a conveying pipe and moved, and the moving plugs are conveyed. The volume and the moving speed are measured by using two pressure gauges installed in the pipe, and the injection amount of the additive is controlled according to the passage of each plug through the position of the additive injector. 11-229428).

That is, as shown in FIG. 7, the landfill sand 2 carried by the earthmoving ship 1 is filled with water, or when the landfill sand 2 is a dredged soil with a soft and high water content ratio, it is not filled with water and is left as it is. ,
The back hoe 3 for unloading loads the carrier tube 4 into the hopper 5 at the starting end. The added slurry is hopper 5
It is sent out into the conveying pipe 4 by the lower screw.

An air pressurizing pipe 7 for intermittently injecting compressed air for transportation is communicated with the carrier pipe 4, whereby the earth and sand slurry and a large number of lumped plugs S sandwiched by air portions A as shown in FIG. Will be transported.

Pressure gauges 8a, 8 are provided on the carrier pipe 4 at intervals.
b and the additive material injector 9 is installed on the downstream side thereof, and the moving speed and the plug length are measured when each plug S passes by the change of the detection value by both pressure gauges 8a and 8b. The computer 10 calculates the slurry amount when passing through the material injector position and controls the injection time and the injection amount from the additive material injector 9.

In this conventional method, the additive material mixing amount (additive material mixing ratio) per unit volume with respect to the earth and sand slurry is determined in advance in accordance with the properties of the earth and sand slurry to be used, and the additive material mixing ratio is set. It is controlled by a computer so that it is injected into each plug when they are brought close to each other.

[0008]

In the above-mentioned conventional method, the additive mixture ratio is determined by investigating the properties of the earth and sand slurry fed into the carrier pipe, for example, for each earth carrier being conveyed. Therefore, it is premised that the plug moving in the transfer pipe always has a constant water content.

Therefore, in order to keep the water content ratio of the earth and sand slurry sent to the carrier pipe constant for each plug, the earth and sand in the earth carrier are constantly stirred by using a backhoe for unloading, which is often used for the work. There is a problem that it requires labor and cost.

Even if the material is constantly agitated by a backhoe or the like, the water content ratio cannot be kept constant from the start of unloading to the completion, and the strength of the landfill soil to be charged varies after hardening, and the whole area is spread over the entire area. There was a problem that it was difficult to obtain a landfill with the required strength.

The present invention has been made in view of such conventional problems.
Even if the water content ratio of the earth and sand slurry sent to the carrier pipe varies, the method of mixing the earth and sand slurry in the earth and sand slurry can be adjusted to adjust the injection amount of the additive material to obtain the desired degree of hardening. It was done for the purpose.

[0012]

The features of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose are as follows.
An additive material injector for injecting an additive material mainly composed of a solidifying material such as cement is installed in the middle of the carrier pipe for pneumatically feeding the earth and sand slurry in which water is mixed with the earth and sand, and the additive material from the additive material injector In the mixing method in the additive material pipe for the earth and sand slurry to mix the additive material in the earth and sand slurry by controlling the injection timing and the injection amount of the additive material by the control means using a computer, of the additive material to the water content ratio of the earth and sand slurry to be conveyed. The proper mixing ratio is input in advance in the computer, the water content ratio of the earth and sand slurry is measured before the earth and sand slurry reaches the additive material injector in the carrier pipe, and the injection amount from the additive material injector, The adjustment is made in correspondence with the proper mixing ratio of the additive material with respect to the water content ratio which is previously input to the control means.

In the above method, a temporary storage tank for measuring the water content ratio is installed at the upstream end of the transfer pipe, and the density of the earth and sand slurry in the temporary storage tank is calculated from the value measured by a γ-ray density meter. By measuring the water content ratio, and by providing a pair of pressure gauges on the upstream side of the additive material injector position of the transport pipe with a gap in the plug movement direction side, inside the transport pipe detected by both pressure gauges. Due to pressure fluctuation,
To measure the moving speed of each plug and the volume of each plug of the earth and sand slurry that is conveyed as a number of lumped plugs sandwiching the air portion, and to control the injection timing of each plug from the additive injector. Is preferred.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic of an apparatus embodying the present invention. In the figure, reference numeral 20 is a soil carrier for transporting landfill sand such as highly concentrated dredged soil, and 21 is a sand pump for excavation. Reference numeral 22 is a temporary storage tank for temporarily storing the earth and sand slurry pumped by the sand pump 21. The temporary storage tank 22 is provided with a γ-ray densitometer 23 for measuring the density of the earth and sand slurry therein, and the lower end of the temporary storage tank 22 communicates with the starting end of the transport pipe 24. The pneumatic pipe 25 is connected to the carrier pipe 24 in the same manner as the conventional example described above.
A pair of pressure gauges 2 are provided downstream of the pressure gauge 2 with a small interval in the flow direction.
6a and 26b are installed, and the additive injection device 2 is provided downstream thereof.
7 is provided.

When the water content of the landfill soil in the earth transport ship is not enough to move in the carrier pipe 24, the sand pump 21 injects water into the pumped-up portion of the earth transport ship and sucks the earth and sand slurry. To excavate. If the landfill sand carried by the earthmoving ship has a high water content, such as dredged soil, it should be sucked as it is.

The air pressure feeding pipe 25 is adapted to intermittently feed the high pressure air into the carrier pipe 24, whereby the earth and sand slurry fed from the temporary storage tank 22 into the carrier pipe 24 is sandwiched between the air portions A. A large number of plugs S are moved.

Both the pressure gauges 26a and 26b are adapted to measure in real time the fluctuation and the magnitude of the pressure inside the pipe due to the movement of the air portion A and the plug S in the conveying pipe 24.

In the additive material injector 27, an injection nozzle 27a for injecting an additive material mainly composed of cement milk is used as the carrier pipe 2.
4, the injection timing and the injection amount from the injection nozzle 27a are controlled by the injection control means 28 using the computer 28a.

In the injection control means 28, the γ-ray density meter 23,
The injection timing and the injection amount of the additive material for each plug S are controlled based on the measured values of both pressure gauges 26a and 26b.

The injection control means 28 calculates the water content ratio of the earth and sand slurry according to the following soil formulas (1) and (2) from the measured value by the γ-ray density meter 23. That is,

[0022]

[Equation 1]

Γt: wet unit volume weight (tf / m3) Gs: soil particle density (specific gravity) e: void ratio Sr: saturation (%) γw: unit volume weight of water (tf / m3) w: water content ratio ( %) Equations (1) and (2) The saturation Sr is 100%, and the soil particle density Gs is obtained in advance by an indoor soil test. The soil particle density is a characteristic soil constant for the soil in the area, and does not change significantly if the dredged soil is in the same area. Then, the water content ratio w is calculated for each density value (wet unit volume weight γt) obtained by the γ-ray densitometer 23.

On the other hand, in the computer 28a, the additive material mixing ratio for obtaining a desired target strength corresponding to the change of the water content ratio w is mathematically entered and inputted, and based on the additive material mixing ratio data, The required additive material mixture ratio is selected in accordance with the water content ratio obtained by the calculation formula, and the additive material injection amount by the additive material injector 28 is controlled.

The preparation of this additive material mixture ratio data is shown in FIG.
As shown in Fig. 6, the water content ratio of the earth and sand slurry is divided into several stages, and the mixed amounts of the additive materials are mixed for each of the samples S1, S2, and S3, and the strength after solidification is measured for each mixed amount to obtain a graph. From this graph, as shown in FIG. 4, a graph of the additive material mixture amount for obtaining the target strength with respect to the change of the water content ratio is created.

Furthermore, in order to prevent a shortage of the additive when the water content value detected is extremely small, and when the water content value is extremely large, damage to the device may occur due to an excessive amount of the additive material injected per unit time. In order to prevent this, a graph in which a certain minimum injection ratio and a maximum injection ratio are set for a portion outside the expected water content ratio is created as shown in FIG.

Further, from the pressure change value in the transfer pipe 24 obtained by both the pressure gauges 26a and 26b, the computer 2
8a is used to calculate the weight (or length) of the plug S when passing through the position of the additive material injection pipe, and in response to the change in the amount of earth and sand slurry for each plug S, when the additive material is injected and when the additive material is injected into each plug S. Control the timing of.

That is, the computer 28a calculates the weight (or length) of each plug S in the transport pipe 24 based on the peak value p of the pressure curve detected by the pressure gauges 26a and 26b as shown in FIG. And two pressure gauges 26a and 26b
The flow rate of each plug S (earth and sand slurry) is calculated based on the detection time difference t of the peak value p of the above, and the injection amount (or injection time) of the additive material by the additive material injector 27 corresponding to the weight and the flow rate of each plug S. ) And infusion timing.

That is, it has been confirmed by an experiment that the pressure rises when each plug S passes through the carrier pipe 24. As shown by the solid line in FIG. 6, the tip of the plug S is provided with the pressure gauge 26a. At time t0 when passing the point, the pressure gauge 26a
The peak value p is detected by the pressure gauge 26a at the time t1 which is slightly delayed from the time t0 after the measured value of No. 1 starts to increase. Then, as indicated by the broken line in FIG. 6, when the same plug S passes through the installation location of the pressure gauge 26b on the downstream side, at the time t2 which is later than the detection time t1 on the upstream side, the peak value p is measured by the pressure gauge 26b. Is detected.

Then, the detection time difference t between the installation interval d of the pressure gauges 26a and 26b and the peak value p of the pressure gauges 26a and 26b.
From (t = t2-t1), the flow velocity v of the plug S (v = d
/ T) can be calculated, and from the flow velocity v of the plug S and the distance l between the pressure gauge 26b and the injection nozzle 27a, the time t3 (t3 = t3 = t3 = t3 = t3 = t3 = t3 = t3 = t3 = t3 = t3 = t3) at which the tip of the plug S passes the installation position of the injection nozzle 27a. 1 / v + t0) is calculated.

Therefore, when the tips of the many plugs S, S ... Pass through the injection nozzle 27a, the injection nozzle 27
It is possible to start the injection of the additive into the transport pipe 24 by a, so that the additive is supplied to the air portions A, A ... Even if the intervals between the plurality of plugs S, S ... Are not constant. The additive material can be reliably added to each of the plugs S, S ...

The installation interval e of the pressure gauges 26a and 26b
Is relatively narrow and there is only one plug S between the pressure gauges 26a and 26b, the same plug S is detected by the downstream pressure gauge 26b immediately after being detected by the upstream pressure gauge 26a. 2 pressure gauges 26
The detection results of a and 26b can be easily associated with each other. Further, since the peak value p or the waveform detected by the pressure gauges 26a and 26b has a characteristic for each plug S, S ..., Based on the peak value p or the waveform, two pressure gauges 26a and 26b related to the same plug S are provided. The detection results may be associated with each other.

The peak value p detected by the pressure gauge 26b is substantially proportional to the weight W of each plug S (W = a).
It has been confirmed by experiments that p + b (a and b are constants). The length (volume) of each plug S is proportional to its weight W, and thus to the peak value p of the pressure gauge 26b.

With respect to the weight W of each plug S calculated in this way, the computer 28a is prepared in advance so that the additive material mixing ratio corresponds to the water content ratio calculated from the measurement value of the γ-ray density meter 23 described above. The additive material injection amount is calculated according to the calculation formula programmed in the above, and the additive material injection amount from the additive material injector 27 to each plug S is controlled.

It should be noted that the injection speed of the additive material by the injection nozzle 27a is kept constant and the injection time is controlled so as to be proportional to the peak value p of the pressure gauge 26b.
The injection speed of the additive material can be adjusted so that the injection time of the additive material is just finished when the rear end passes through the installation position of the injection nozzle 27a, and thus, even when the plug S is long, The additive material can be uniformly added from the front end to the rear end of the plug S without being biased.

[0036]

As described above, in the method for mixing the additive slurry with the earth and sand slurry according to the present invention, the solidifying material such as cement is provided in the middle of the carrier pipe for pneumatically feeding the earth and sand slurry in which water is mixed with the earth and sand. When an additive material injector for injecting an additive material mainly composed of is added, and the injection timing and the injection amount of the additive material from the additive material injector are controlled by a control means using a computer, The proper mixing ratio of the additive material to the water content ratio is input to the computer in advance, and the water content ratio of the earth and sand slurry is measured before the earth and sand slurry reaches the additive material injector in the carrier pipe, and the additive material injector Injection amount from
Even if the water content ratio of the earth and sand slurry fed into the transfer pipe changes, it is automatically adjusted to this by adjusting so as to correspond to the proper mixing ratio of the additive material with respect to the water content ratio previously input to the control means. It will be possible to mix the injection amount of the additive material so as to have a desired and required mixing ratio set in advance following the above, and a work process for keeping the slurry water content constant for feeding into the carrier pipe as in the conventional case. This makes it possible to obtain landfill sand mixed with additive materials of a certain quality economically, and especially when forming a solidified ground layer for the trafficability of heavy equipment on the surface layer of a soft landfill site. When it is necessary to finely adjust the strength of the landfill after solidification, such as when you want to obtain strength that is easy to drive in, easily create the ground with the required strength. Door can be.

Further, a temporary storage tank for measuring the water content ratio is installed at the upstream end of the carrier pipe, and the density of the earth and sand slurry in the temporary storage tank is calculated from the value measured by the γ-ray densitometer to obtain the water content ratio. By measuring, the change in the water content ratio can be measured in real time.

Further, a pair of pressure gauges are provided on the upstream side of the position of the additive injector of the carrier pipe at intervals in the plug moving direction side, and the carrier pressure in the carrier pipe is detected by the pressure gauges. The moving speed of each plug and the volume of each plug of the earth and sand slurry that is conveyed as a number of lumped plugs sandwiching the air portion in the pipe are measured, and the injection timing for each plug from the additive injector is measured. By controlling, even if there are variations in the length of the plugs, it is possible to mix the additive material uniformly over the entire length of each plug.

[Brief description of drawings]

1 is a schematic view showing an example of an apparatus for carrying out the method of the present invention.

FIG. 2 is a partially enlarged sectional view of the device shown in FIG.

FIG. 3 is a graph showing the relationship between the amount of solidifying agent added and the strength after solidification for each sample of earth and sand slurry having different water content ratios.

FIG. 4 is a graph showing a solidifying material addition amount for each sample for obtaining the target strength in FIG.

FIG. 5 is a graph in which a proper mixing ratio of an additive material corresponding to a change in water content ratio is mathematically expressed.

FIG. 6 is a graph showing changes over time in the pressure detected by the pressure gauge in the apparatus shown in FIG.

FIG. 7 is a schematic view of an apparatus used in a conventional method.

FIG. 8 is a partially enlarged sectional view of the same article.

[Explanation of symbols]

A air part S plug 20 Earth Transport 21 Sand Pump 22 Temporary storage tank 23 γ-ray densitometer 24 carrier tubes 25 Pneumatic tube 26a, 26b Pressure gauge 27 Additive material injector 27a injection nozzle 28 Injection control means 28a computer

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Claims (3)

[Claims] 1. An additive material injector for injecting an additive material composed mainly of a solidifying material such as cement is installed in the middle of the carrier pipe for pneumatically feeding the earth and sand slurry in which the earth and sand are mixed with water, and the additive material is injected. In the mixing method of the additive material in the additive material pipe for mixing the additive material into the earth and sand slurry by controlling the injection timing and amount of the additive material from the vessel by the control means using a computer, the water content of the earth and sand slurry to be conveyed The appropriate mixing ratio of the additive material to the ratio is input in advance in the computer, the water content ratio of the earth and sand slurry is measured before the earth and sand slurry reaches the additive material injector in the carrier pipe, and the additive material injector The amount of injection of water is adjusted in accordance with an appropriate mixing ratio of the additive material with respect to the water content ratio previously input to the control means. Mixing method for pipes with additives. 2. A water storage ratio is provided by installing a temporary storage tank for measuring the water content ratio at the upstream end of the carrier pipe, and calculating the density of the earth and sand slurry in the temporary storage tank from the value measured by a γ-ray densitometer. The method for mixing in an additive material pipe to the earth and sand slurry according to claim 1, wherein 3. The upstream side of the position of the additive injector in the carrier pipe,
Equipped with a pair of pressure gauges at intervals on the plug movement direction side,
The movement speed of each plug and the volume of each plug of the earth and sand slurry that is conveyed as a large number of lump-shaped plugs sandwiching the air portion in the transfer pipe due to the pressure fluctuations in the transfer pipe detected by the both pressure gauges. The method for mixing in an additive material pipe for earth and sand slurry according to claim 1 or 2, which measures and controls the injection timing of each plug from the additive material injector.