JPS60114360A - Device for recovering high-concentration mud water for shield driving method - Google Patents

Abstract

PURPOSE:To recover and economize the clay and bentonite components in mud water by washing muck with a small amt. of dilute mud water on an excavation site, separating a gravel-component and a mud-component and reutilizing the separated mud water. CONSTITUTION:A pool part 19 is provided in a muck charging part of a screen for rough gravel of a vibration screen and the muck is charged into the pool part 19. The mud water and sand separated by screening are stored in a mixing, circulating and storing tank 4. The mud water and sand are admitted by a pump 5 into a cyclone 6 and a part of the mud water of the overflow is also admitted into the pool part. The rest is stored in a circulating mud water tank 7. The mud water from the tank 7 is further admitted into the tank 4 by a pump 8. The costly bentonite and clay components are thus recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for recovering highly concentrated muddy water from the excavation side generated in the muddy shield method.

1- (Problems to be solved by the invention) In general, the excavation process that occurs in the muddy shield method involves the mixing of high-concentration mud, which is injected into the face by an excavator, and soil from the ground, resulting in hardened fresh concrete IJ. - It is discharged in the form of a tortoise. The solid voids in this discharge bottle are filled with slurry, and the liquid pressure can be maintained inside the excavator, so when transporting it by car, it will be handled as liquid. There was a risk that mud would leak onto the road during transportation, staining the road, or that mud would splash and cause secondary pollution. In order to prevent this, the borage is put into a water tank and washed, the sand and gravel are separated from the mud, and the mud is dehydrated. However, such treatment requires a large amount of water, requires a huge amount of equipment, and takes up a large amount of space. Furthermore, muddy water containing bentonite is difficult to dispose of at dump sites, is designated as industrial waste, and has drawbacks such as extremely high processing costs.

The present invention relates to a treatment device for a mixture of high-concentration mud and borage. Wash the porcelain with as little diluted mud water as possible on site, remove the mud, separate the sand and gravel, and reuse the separated mud as mud water to remove the clay and bentonite present in the mud. The purpose is to recover and save.

(Structure, operation, and effect of the invention) The present invention provides a pool part in the side installation part of the screen for coarse gravel of a vibrating sieve, and puts a rice bowl into the pool part to mix the sieved muddy water and sand into a mixed circulation storage tank. This muddy water and sand are pumped into the cyclone via an inflow pipe, a part of the overflow muddy water is flowed into the pool part, the rest is stored in a circulating muddy tank, and the muddy water is pumped from the circulating muddy tank. This is a high-concentration mud water recovery device in which the mud flows into a mixed circulation mud tank via an inflow pipe.

Next, the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 2 denotes a cylinder body, and the cylinder body is configured to vibrate in an oblique direction by a vibrator (not shown). Reference numeral 19 denotes a pool portion provided at the borium input portion of the debris screen 15. Highly concentrated mud water transported from the excavation site and borage mixed with earth and sand are added to this.

20 is a weir plate provided in the pool. The mesh size of this gravel screen 15 is 15 mm. Reference numeral 16 denotes a screen for fine gravel, which is provided at the lower stage of the screen for fine gravel 15, and has a mesh size of, for example, 2.5 wun. 1 is a drain inlet, and a portion of muddy water from the overflow from the hydrocyclone is supplied to this X from an arrow A through a water pipe 18.

In other words, as the cylinder body 2 vibrates in the oblique direction, a mixture of highly concentrated muddy water, sand and gravel from the ground, and a sufficient amount of water enters the technical input section 19.
The sand and crushed meat surfaces are diluted with washing mud water from the washing water pipe 18, and the particles are subjected to friction between particles in the mud water due to vibration, and the mud particles stuck to the sand and crushed meat surfaces are removed. The sand is thus separated from the fixed mud.

The gravel and mud water pass over the weir 20 to the gravel screen 15, where coarsely crushed solid particles are sized, and the fine particles are further sent to the granule screen 16, where the granules are sized.

4- The separated muddy water and sand flow down from the gravel screen 16. The separated coarse particles and fine particles are discharged in the direction of arrow B.

The sand and muddy water from which the coarse and fine particles have been separated by the cylinder body 2 are stored in the mixing circulation tank 4 from the under-sieve water collection gutter 3, and the muddy water and sand are sent to the liquid cyclone 6 by the circulation pump 5. A part of the upper liquid separated by the liquid cyclone 6 is supplied to the discharge masonry inlet 1 through a pipe 18, and the other part is branched off and stored in the mud water circulation tank 7 through a pipe 21.

On the other hand, the concentrated and collected underflow of the liquid cyclone 6 is returned to the sand screen 17 of the cylinder body 2. The underflow returned to the sand screen 17 is dehydrated by vibration and discharged from arrow B as dehydrated sand. The sand screen 17 is a wedge wire screen with a slit of 0.5+++s.

The sand and mud in the mixing circulation tank 4 are circulated by a pump 5. An upper limit level meter 10 and a lower limit level meter 11 are provided for the mixing circulation tank 4, and when the water surface reaches the lower limit level meter 5-, muddy water is replenished from the muddy water circulation tank 7 by the pump 8, and when the upper limit level meter is reached, the operation is stopped. It looks like this. The capacity of the mixing circulation tank 4 should be kept as small as possible.
It is necessary to prevent sand deposition.

The circulating mud water tank 7 is filled with mud water whose initial concentration has been lowered, and the concentration increases during circulation washing, and when the specific gravity set on the hydrometer 9 is reached, the washing is temporarily stopped.

The pump 13 pulls out the muddy water from the circulating muddy water tank 70 to the level of the level meter 10' and sends it to the first recovery muddy water tank 14.

The pump is stopped by a signal from the level meter 10' of the circulating mud tank 70, and the water supply valve 12 adds water through its opening, and when it reaches the level meter 11' of the circulating mud tank 7, the valve 12 is closed and cleaning begins. There is.

The mud water required for mud production is less than 30% of the excavation volume.
The concentration is around 50%. Also, the ratio of the mud content in the discharged pot to the mud content plus water, that is, the mud content concentration Cd
Let Sd ton be the mud content and Wd ton be the moisture content, then the clay to water content ratio, the concentration of high-concentration mud injected into the face, and the injection rate [ratio of volume of injection volume per volume of excavated rock ( It can be calculated from the amount of excavated soil (0-2 m! per 1 m3 of excavation is 20%)] and the loss rate of mud (sludge that penetrates into the ground and is lost and is not discharged with the excavated soil).

On the other hand, the water required for mud cultivation is as follows.

Example of mud composition: Clay 0.5t/7r? C) Bentonite 0.15 p (p) Water 0.75
〃(tr) Total 1.42 t/n? (tr) Assuming that the slurry injection rate is 20% of the excavation amount.

Is the injection amount 1rr excavation amount? It becomes 0.2- for each. Susuwachi clay 0.1t/silent bentonite 0.03t/d water 0.1!5t, /77/7-.

Therefore, if the excavated amount is dehydrated by some method, separated into sand and gravel and muddy water, and the water in the muddy water recovered from the excavated amount of 1 m3 is less than 0.15 m', clay, bentonite, and If each is replenished by the difference from the above values, it can be reused as the injection amount. Also, if the water in the collected muddy water is larger than the above water 0.15772', the water is 0.1577
Clay and bentonite equivalent to 1' can be reused, and the excess will be disposed of. When reusing, there is less clay and bentonite and the root recovery rate is high. However, the concentration of mud discharged from the shield machine is too high to be directly separated from the mud, so it is necessary to use mud water with a low concentration for cleaning.

If the amount of washing water is constant during washing, the lower the concentration of washing water, the more effective the washing will be, but if the amount of water after washing becomes larger than the amount of water for mud making by lowering the concentration, as mentioned above, it will be excessive water. Since it often ends up being disposed of, it cannot be considered as being collected. The present invention was invented with such balance in mind.

8- As the muddy water initially charged in the circulating muddy water tank is circulated and cleaning continues, the concentration of the circulating muddy water becomes higher as it dissolves the mud in the discharge tank. Figure 2 shows the washing and recovery operation. It is a graph showing the situation of one cycle. That is, (1) the concentration of muddy water increases as the number of washings increases, and approaches the concentration of muddy water in the discharge bowl as an asymptote. (2) The amount of surplus muddy water is l IJ
This calculation is based on the assumption that mud is produced every time one ring of shield segment is excavated (the unit of excavation is one ring of shield segment), and when one ring of mud is separated at the completion of one ring excavation, there will be a surplus of 2.7-. Muddy water occurs. 2 rings (R)
2.4 when making mud for 2 rings upon completion of excavation
− Surplus muddy water is generated. Similarly, when excavating 5R and producing mud, excess mud water can be turned into O.

The reason why the surplus mud water decreases is that the water adhering to the surface of sand and gravel carries out mud.In the initial stage, the mud concentration is low, so less mud is carried out, and as the concentration increases, the amount carried out increases.

This tendency is due to the extreme amount of water initially charged and the water content ratio of the ground.

9- The grain size of the ground changes significantly depending on the ratio of sand in the composition. By washing in this way.

(1) Due to the high recovery rate, the amount of expensive bentonite and red clay used is significantly reduced, resulting in a reduction in construction costs.

(2) By mixing and averaging the initial and final stages of sand and gravel, sand and gravel with good cleaning effects can be obtained and can be effectively used as an aggregate resource.

(3) Secondary pollution caused by the transportation of waste bottlings, disposal sites, etc. will be resolved.

(4) Since surplus mud water is not generated, there is no need for treatment equipment for bentonite mud water, which has poor filterability.

There are several advantages, and the effects of the present invention are very large.

[Brief explanation of drawings]

Figure 1 shows a highly concentrated mud water recovery device using the shield method of the present invention.
FIG. 2 is a graph showing the relationship between the number of cleaning rings, the amount of surplus mud water, and the concentration of mud water when using the apparatus of the present invention. l...Discharge basin input port 2...Cylinder body 3...Sieve water collection gutter 4...Mixing circulation tank 10-5...Circulation pump 6...Liquid cyclone 7...Muddy water circulation Tank 8...Pump 9...Hydrometer 10.10'...Lower limit level gauge 11.11'...Upper level gauge 12...Valve 13...Pump 14...Recovered mud water tank 15 ...Gravel screen 16...Fine gravel screen 17...Sand screen 18...Water pipe 19...Pool section 20...Weir board 21...Administrative agent Patent attorney Yoshi Shima Nei 11-

Claims (1)

[Claims] A sand screen is provided on the upper stage and a coarse sand screen is provided on the lower stage, and a 4-inflated elliptical storage tank for muddy water and l is provided below the vibrating sieve, which has a pool part in the stone input part of the coarse sand screen. A high-concentration muddy water recovery device using the shield method, which is characterized by a mixing storage tank, supplying muddy water to a cyclone, and causing underflow of the cyclone.