JPH0216295A - Method of transferring earth by application of pressure - Google Patents

Abstract

PURPOSE:To improve pressure maintenance and cut-off properties, to enhance fluidity and to prevent the blockade of a transport pipe by mixing the gel of various forms of continuous high water-absorbing resin into soil and sand forcibly fed through a pump as a lubricant. CONSTITUTION:The gel of various forms of continuous high water-absorbing resin is mixed into soil and sand as a lubricant, and forcibly fed through a pump. Accordingly, sections among the soil particles of excavating soil and sand are filled with gel, thus approximately removing the voids of soil and sand.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for pumping earth and sand, and particularly to an improvement in a method for pumping earth and sand.

(Prior art) As is well known, the shield method is a method for constructing tunnels such as subway tunnels, and various construction methods are available, but recently the shield method, which uses a sealed shield excavator, is relatively popular. It is widely used.

In the closed shield construction method, a chamber is usually separated from the front side of the shield excavator, and the chamber is filled with excavated soil to increase the pressure inside the chamber so as to face the face.

The excavated earth and sand that has filled the chamber will be discharged outside while preventing the face from collapsing as the shield excavator advances, but if the excavated earth has no fluidity at this time, it will be difficult to discharge it. .

Therefore, in order to give fluidity to the excavated soil, a method was developed in which a spherical super absorbent resin was added and mixed as an anti-friction material.
It is disclosed in Japanese Patent No. 2-211491.

According to the method disclosed in this publication, when spherical superabsorbent resin is added and mixed with excavated soil, it is said that the bearing effect of the resin makes it easier to discharge.
When pumping excavated soil, there were technical issues as explained below.

(Problem to be Solved by the Invention) In other words, according to experiments conducted by the present inventors, when excavated soil is pumped using the method disclosed in the above-mentioned publication, it is possible to give the excavated soil enough fluidity to be sucked by the pump. It has been found that excavated soil mixed with spherical superabsorbent resin has a large number of voids, which causes moisture to enter during pumping and easily clog the transport pipe.

The inventors of the present invention repeatedly conducted various experiments in order to eliminate such problems, and as a result, they learned that such problems could be eliminated by using a special super absorbent resin, and based on this knowledge, The present invention has been completed, and its purpose is to provide a method for pumping earth and sand that can obtain the fluidity necessary for suction with a pump and that can be pumped without clogging transport pipes. be.

c) Means for Solving the Problems) In order to achieve the above object, the present invention provides a method of mixing an anti-friction material with earth and sand and pumping the mixture using a pump, in which the anti-friction material is an amorphous continuous material. It is characterized by using a gel of super absorbent resin.

(Operations and Effects) According to the earth and sand pumping method with the above configuration, the antifriction material mixed with the excavated earth and sand is a gel of an amorphous continuous superabsorbent resin, so this gel fills between the soil particles of the excavated earth and sand. As a result, liquidity increases and
Almost no gaps are formed.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an experimental device used to confirm the effects of this invention.

In this experiment, spherical super absorbent resin A (product name A-m)
and two types of super absorbent resin B that form an amorphous continuous gel.
(Product Name D-2350) and C (Product Name S-100) were prepared, and their suitability for pumping was determined by examining their pressure retention and water stop properties when they were added and mixed with earth and sand.

As an experimental device, a sample soil tank 10 containing sample soil is used.
0 (inner diameter 300φ x height 500+n+s) and a water tank 103 connected to this tank 100 via cocks 101 and 102 are prepared, and a pressure gauge 104 and an open cock 106 are attached to the upper end of the sample soil tank 100. A vibrator 108 having a solenoid valve 107 was connected to the lower end of the tank 100.

An open cock 109 and a compressed air supply pipe 110 were attached to the upper end of the water tank 103.

As the earth and sand material to which the superabsorbent resins A, B, and C are added, pea gravel with a diameter of 5 dragons having an extremely uniform particle size distribution was prepared.

This pea gravel was drained before being mixed with superabsorbent resins A, B, and C, and its saturation level was S −1 00%, and the unit pile weight was 7 t −1−94 gf′/
I set it to cm.

Gels of super absorbent resins A, B, and C and sample soil were prepared in the following manner.

■Preparation of gel Powder weight W of super absorbent resins A, B, and C. (g) was used after absorbing 1 kg (Igχ) of tap water and leaving it for 24 hours.

At this time, the gel concentration C, (%) is CG (%)-WG/1000xlOO-〇, IWG Let us express it as

■Preparation of sample soil Add 4J of gel prepared in ■ to 10β of gravel after draining water.
They were added at a ratio of 2:2 and mixed well to prepare a sample soil.

Each of the sample soils obtained as described above was divided into three layers into the sample soil tank 100 and compacted lightly with a protrusion rod so that the height thereof was approximately 45 an.

Next, the cock 101 and the solenoid valve 107 are opened,
The cock 102 was opened above the sample to inject water, and at the same time, the open cock 106 was opened to vent air.

Then, the solenoid valve 107 was closed when water permeated into the sample soil and began to flow out from the pipe 108.

As described above, when the air in the sample soil tank 100 and the water penetration into the sample soil are completed, each cock 1
06.107 was closed and the sample soil was supplied with water under pressure with cocks 101 and 102 open.

The set pressures in the sample soil tank 100 due to this water supply pressurization are 0.5, 1.0.1.5, 2. Okgf'/C-, and when these predetermined pressures are set, the cock 101 is closed and the pressure in the sample soil tank 100 is maintained at that state.

Then, the electromagnetic valve 107 was opened for 10 seconds, and the pressure maintained inside the sample soil tank 100 during that time was measured and recorded via the pressure gauge 104 every 0.005 seconds.

Additionally, during this period, the amount of water flowing out from the pipe 108 was also measured using the beaker 111.

Figures 2 to 5 show the measurement results obtained in the pressure holding test.

FIG. 2 shows the measurement results when no superabsorbent resin gel is added. 0.7 seconds after the electromagnetic valve 107 is opened, the pressure inside the sample soil tank 100 becomes atmospheric pressure, and even after that, water continues to flow out, so the pressure becomes a negative value.

Table 1 shows the amount of water flowing out at this time.

Naturally, the higher the set pressure in the sample soil tank 100, the greater the amount of water flowing out.

FIG. 3 shows a case where a spherical gel of super absorbent resin A is used.
After a few seconds, the pressure inside the sample soil tank 100 became atmospheric pressure.

During this period, the amount of water flowing out from the electromagnetic valve 107 increased by approximately twice as much as in the case where no gel was added, as the pressure retention property was improved.

Note that the gel concentration was CG-1.2%.

FIG. 4 and FIG. 5 show the case where superabsorbent resins B and C, which form an amorphous continuous gel according to the present invention, are used.

Figure 4 shows the case where D2350 is used as the superabsorbent resin B, and as is clear from comparison with Figure 3, even when the gel concentration CG is half (0.6%), the solenoid valve 107 is opened. In some cases, the pressure reaches atmospheric pressure after 10 seconds, and pressure retention can be improved with a smaller amount added than super absorbent resin A.

As described above, the pressure retention property is improved, and at the same time, the amount of water flowing out is reduced to about 20% of that of the super absorbent resin A, and the water stop property is also improved.

Figure 5 shows the case where S-100 is used as super absorbent resin C, and the pressure retention property when the gel concentration is C6-0.6% is higher than that of other super absorbent resins A and B. The pressure inside the sample soil tank 100 is very good, and the pressure inside the sample soil tank 100 is controlled by the solenoid valve 10.
Even after 10 seconds of opening No. 7, there is very little variation.

In addition, the amount of water flowing out was reduced to less than 50% of super absorbent resin A and about 1/2 of that of super absorbent resin B, demonstrating extremely good water stopping properties.

In the above results, a good pressure retention property means that gaps are unlikely to occur in the sand, and a good water stop property means that water is removed from the sand by the pump pressure when the sand is pumped. It is less likely that the water will be separated and sent, and there will be no chance of water getting ahead and clogging the transport pipe during pumping.

Figure 6 shows that the spherical super absorbent resin A has the property of not being easily crushed, so it can be expected to be effective as a plugging material.
The test results are shown when these were mixed and used with the gel concentration C6 of C being 0.5%.

FIG. 6(A) shows the measurement results when D2350 is used alone, and since the gel concentration is lower, the pressure retention property is slightly lower than that shown in FIG. 4.

Figure (B) shows a case where a mixture of D2350 and A-III at a ratio of 3:1 is used, and in this case, the pressure retention is better than in the case shown in Figure (A). decreased.

In the same figure (C), a mixture of D2350 and A-m in a ratio of 1=1 is used, but in this case, the pressure retention property is further reduced, and the filling material is not as expected. No effect was obtained.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the experimental equipment used to confirm the effects of the method of the present invention, and Figures 2 to 6 are graphs showing the results of pressure holding tests conducted using the same experimental equipment. .

Claims (1)

[Claims] (1) An earth and sand pumping method in which an anti-friction material is mixed with earth and sand and the mixture is pumped through a pump, characterized in that an amorphous continuous super absorbent resin gel is used as the anti-friction material.