JPS589238B2 - Mud water pressurized shield excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention supplies pressurized water to the pressure chamber of the main body of the shield excavation machine to maintain the face surface and pressurize muddy water to excavate while excavating earth and sand from the pressure chamber using a rotary valve. Regarding the shield excavator, an object of the present invention is to provide a mud water pressurizing shield excavator that can reduce the pressure fluctuation in the pressure chamber due to the discharge of earth and sand from the rotary valve and shorten the stabilization time after the fluctuation.

A conventional shield tunneling machine of this type will be explained below with reference to FIG.

In Fig. 1, numeral 1 indicates the main body of the mud water pressurizing shield excavator.

This shield tunneling machine main body 1 has a pressure chamber 3 opposing a face 2.
The pressure chamber 3 has a water supply pipe 5 having a booster pump 4.
is connected to the pressure chamber 3, thereby connecting the intermediate tank 6 to the pressure chamber 3.
of stored water is being supplied.

On the other hand, the earth and sand excavated by Katsuta 7 together with boulders 8 are in the pressure chamber 3.
After being taken in, the water mixes with the pressure water and is introduced into the rotary valve 10 through the communication port 9.

Then, the pressure chamber 3 is controlled by this rotary valve 10.
The rotary valve 1 is sealed with pressure between the indoor and outdoor areas.
0 through the discharge pipe 11 connected to the first mud collection tank 12
can be stored in

Usually, a filter 13 is disposed at the opening of the first mud collecting tank 12, and this filter 13 collects the boulders 8 and muddy water 1.
4 are separated, and the boulders 8 are loaded onto a transport vehicle 16 via a belt conveyor 15 and transported to the ground.

The separated muddy water 14 is transferred from the first mud collecting tank 12 to the agitator 1 by a mud feeding pipe 18 having a submersible pump 17.
It is sent to the second mud collection tank 20 having a tank 9.

This second mud collection tank 20 and the intermediate tank 6 are connected to the partition wall 2
1, and if necessary, the water supplied to the intermediate tank 6 can be made to overflow to the second mud collecting tank 20 side as shown by an arrow 22.
The amount of muddy water can be maintained at 0.

The muddy water in the second mud collection tank 20 is pumped through the mud removal pump 23.
Sludge is discharged to the ground through a drainage pipe 24 having a sludge pipe.

24a is a water supply pipe of the intermediate tank 6, 25 is a valve installed in the mud supply pipe 5, and 26 is a valve installed in the discharge pipe 11.

By the way, as mentioned above, the rotary valve 10 moves the excavated soil to the discharge port 11 side while sealing the pressure in the pressure chamber 3, but its structure is extremely simple, and it does not move the excavated soil into the discharge port 11. When discharging sediment,
The rotary path after the rotary valve 10 discharges earth and sand (this will be described later).

), the pressure in the pressure chamber 3 is easily released, which causes the face 2 to collapse.

That is, during the discharge, the same phenomenon occurs as if a valve were provided in the pressure chamber 3 and the valve was momentarily opened.

As described above, the conventional valve has a serious problem in maintaining the pressure in the pressure chamber 3, but the present invention provides a special means for the rotary valve 10 and maintains the pressure in the pressure chamber 3.
This problem is attempted to be solved by providing a bypass pipe 27 for discharging the pressure muddy water separately from the rotary valve 10.

Examples thereof will be described below based on FIGS. 1 to 3.

28 is a rotary valve according to the present invention.

The rotary valve 28 consists of a casing 31 having a muddy water inlet 29 connected to a muddy water communication port 9 at the bottom and a muddy water discharge port 30 at the top, and a rotating body 32 housed in the casing. It has a large number of partition plates 34 that are rotated around a shaft 33 and protrude radially, and a large number of muddy water storage chambers 35 are formed by the partition plates 34 and the casing 31.

This accommodation chamber 35 has the inlet port 29 and the outlet port 30.
It has almost the same opening area.

Furthermore, the rotating body 32 and the front and rear plates 31a, 3 of the casing 31
lb, gaps 1 and 1 are formed through which the muddy water introduced from the inlet 29 can pass, and the earth and sand is accommodated in the storage chamber 35, but the muddy water 36 passes through the gap. After the earth and sand are discharged, the empty storage chamber 35 is filled.

That is, among the rotary paths through which the storage chamber 35 passes as the rotating body 32 rotates, the rotary path after the earth and sand is discharged between the discharge port 30 and the inlet 29 (hereinafter referred to as the earth-and-sand-free rotary path).

) is filled with water, so half of the rotary path of the rotary valve 28 is pressure-sealed by earth and sand, and the other half is pressure-sealed by water.
Pressure fluctuations will be reduced.

In order to obtain such an effect, it is effective to fill 70 to 100% of the volume of the soil-free rotary path with water.

Note that 37 and 38 indicate the introduction and discharge directions of earth and sand, respectively, and 39 indicates the rotation direction of the rotating body 32.

Therefore, in order to keep the mud water pressure in the pressure chamber 3 constant, if the discharge amount of the boost pump 4 is Q and the discharge amount of the rotary valve 28 is Q1, then the following condition is satisfied: Q=Qt+α...(1) It is necessary to

Therefore, in order to obtain α in equation (1), the bypass pipe 2
7 is provided.

Letting the discharge amount of the bypass pipe 27 be Q2, it is α - Q2.

FIG. 4 shows the results of an investigation to confirm the effects of the present invention, and a shows a conventional shield excavator, that is, a conventional rotary valve 10 that does not use the bypass pipe 27 and does not have the gaps 1, 1. When the earth and sand-free rotary path was not filled with water by using the shield excavator, b is a shield excavator according to the present invention, and the pressurized mud water was discharged through the bypass pipe 27, and at the same time, the earth and sand-free rotary path of the rotary valve 28 was filled with water. 3 is a graph showing pressure fluctuations in the pressure chamber 3 in the case of FIG.

As is clear from these, in case b in the present invention,
Compared to the conventional type a, the pressure drop (Po″yl ≦ extremely small) due to the discharge of dirt from the rotary valve, and no overshoot (excessive drop) (p1) of the pressure drop occurs [in the case of a, the pressure drop is Although there is only a variation in delay, in the case of b, a variation in second-order delay occurs.

] Moreover, the settling time (ts) of pressure fluctuation is short.

FIG. 5 shows the effect of the bypass pipe 27 according to the present invention, where a represents the flow rate (discharge amount) Q2 of the bypass pipe 27 as O, and b represents the equal discharge amount of the rotary valve 28 and the bypass pipe 27. In other words, the case where Q1=Q2 is shown below.

According to these, in the case of Q1=Q2, the overshoot (P1) in b is smaller than in the case of Q2-0 in a, and the stabilization time (ts) of pressure fluctuation is also short.

Therefore, the use of the bypass pipe 27 is highly preferred in order to accomplish the purpose mentioned at the beginning.

The present invention aims to minimize the pressure drop and pressure fluctuation in the pressure chamber due to earth and sand discharge in a so-called open mud water shield excavator in which a rotary valve for earth and sand discharge is connected to the pressure chamber of the mud water shield excavator. Moreover, since the settling time of pressure fluctuations can be shortened as much as possible, phenomena such as face collapse can be prevented.

It goes without saying that the gaps 1, 1 between the rotating body 32 and the casing 31 described in the above embodiments must be set within a range that allows muddy water to pass through and maintains the pressure.

Furthermore, in order to fill the soil-free path with water in this way, in addition to filling the water through the gap 11, it can also be done from outside using a pump or the like.

[Brief explanation of drawings]

Fig. 1 is an overall schematic diagram of an embodiment of the present invention, Fig. 2 is a perspective view of the rotary valve 28, Fig. 3 is a vertical sectional side view thereof, and Fig. 4 is the effect of the conventional method a and the present invention b. FIG. 5 is a graph showing the difference in effect between a when Q2=o and b when Q1-Q2 in the embodiment of the present invention. 1... Shield tunneling machine body, 27...
Bypass pipe, 28...Rotary valve, 29
...Muddy water inlet, 30...Muddy water outlet, l...Gap.

Claims (1)

[Claims] 1. A rotary valve for discharging excavated soil is connected to a pressure chamber to which pressure water for maintaining the face is supplied, and a bypass pipe is provided for discharging the pressure mud from the pressure chamber separately from the rotary valve, and the rotary valve is , consisting of a casing having a muddy water inlet at the bottom and a muddy water discharge port at the top, and a rotating body rotatably disposed within the casing and having a plurality of muddy water storage chambers formed around the casing side wall; A muddy water pressurized shield excavator, characterized in that a gap is formed between the and the side surface of the rotating body, through which the muddy water introduced from the inlet can flow into the storage chamber after earth and sand is discharged.