JPH0437919B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] When excavating a tunnel using the shield method, the present invention applies a liquid backfill material to the gap between the segment installed at the rear of the excavator and the ground. on how to pump.

[Prior Art] Generally, when excavating a tunnel using the shield method, a shield excavator excavates and a segment is installed behind it to form the tunnel part.
The difference between the inner diameter of the hole created by drilling and the outer diameter of the segment creates a gap (referred to as a tail void) between the two. If these tail voids are left as they are, they can cause ground subsidence, so a method is used to inject backfilling material into the tail voids and harden them.

In this backfilling process, a liquid injection material is injected into the ground between the segments, and there are two types of injection materials: one-liquid type and two-liquid type.
Liquid type products are becoming mainstream. Injection of backfilling material is disclosed in, for example, Japanese Patent Publications No. 57-53519 and Japanese Patent Publication No. 57-53520.

However, all of these conventional techniques employ a method of detecting the propulsion speed of the shield excavator and controlling the flow rate of the backfilling material in accordance with this excavation speed.

In reality, the state of tail void formation varies widely depending on topography, ground, soil quality, etc., and optimal control cannot be achieved by shield excavation speed alone.

In addition, when injecting the backfilling material, the injection pressure also changes, but in some cases it may not be sufficient to complete the backfilling by injecting it to a certain set pressure, so after a certain period of time has elapsed, the pressure is increased further. It is also necessary to perform a secondary injection in order to achieve complete backfilling.

Conventional back-filling methods do not control the pressure changes of the injection material sufficiently, so back-filling may be incomplete or, conversely, an excessive amount of back-filling material may be injected. The disadvantage was that it was uneconomical.

For example, Japanese Patent Publication No. 57-53519 discloses a technology that controls the flow rate of backfill material by calculating the optimal amount of backfill material to be injected in relation to the excavation speed and comparing the flow rate with the flow rate of injected backfill material. is disclosed. However, since such known technology controls flow rate rather than pressure, it has not been possible to perform sufficient backfilling.

[Problems to be Solved] Therefore, an object of the present invention is to provide a backfill injection method that can detect pressure changes in the backfill injection material and inject enough backfill injection material without excess or deficiency.

[Means for Solving the Problems] According to the present invention, when excavating a tunnel by the shield method, a liquid backfill material pump is used to inject liquid backfill material between the segment installed at the rear of the excavator and the ground. In the injection method, the injection pressure is detected at regular intervals, the relationship between multiple sets of injection pressure and injection flow rate is set in advance based on data on the geology of the ground to be excavated, and the central processing unit calculates the The injection pump is controlled to perform primary injection, and when the injection pressure reaches a predetermined pressure, injection is interrupted, and after a certain period of time, secondary injection is performed at a predetermined injection pressure and injection flow rate.

[Description of effects] Therefore, first, the backfilling material is injected at a low pressure and a flow rate corresponding to that pressure, and when the predetermined pressure is reached, the backfilling material is injected at a higher pressure and a flow rate corresponding to that pressure. Inject the material. The pressure and flow rate are determined by the geological data of the ground to be excavated, so by injecting at different pressures and flow rates multiple times, highly accurate backfill injection can be performed. can. By interrupting the injection for a certain period of time, the primary injected backfilling material is absorbed into the soil and serves to fill in any gaps. Further, during the injection operation, if the pressure rises to a predetermined value or more, it can be determined that the injection operation is completed.

Therefore, according to the present invention, only the pressure is detected and the backfilling material is injected at a predetermined injection flow rate, so the work is easy and the right amount of backfilling material is injected. be able to.

[Preferred mode of implementation] In addition to data regarding injection pressure and geology of the ground, the data judged by the central processing unit can be further expanded by inputting data such as groundwater conditions and shield machine operating status. Highly accurate control can be performed.

[Examples] Examples of the present invention will be described below based on the drawings.

FIG. 1 shows the overall outline of the automatic backfilling system of the present invention. At a tunnel construction site, the tip face is excavated with a cutter of a shield machine 100, and the cut earth and sand is transferred to a screw conveyor 11.
0, conveyed to the ground by a belt conveyor 150 and transported by a vehicle 160 or the like.

Segment 1 is located behind the shield machine 100.
20 will be installed and reinforced, but segment 1
A tail void 140 is formed between 20 and the ground. A backing material is injected into this tail void 140 and cured, but a tail seal 130 is provided to prevent the injected material from flowing into the face portion.

The injection material is a mixture of liquids A and B. First, liquid A is made up of raw materials from silo 1, which contains a hardening agent mainly composed of cement, silo 2, which contains bentonite, and silo 3, which contains fine aggregate. Supplied mixer 6
sent to. On the other hand, water from the water tank 4 is sent to a fresh water cushion tank 5 and supplied to a mixer 6 via a pump 8. The A liquid mixed at a constant ratio is sent to the agitator 7. This agitator 7 is installed in the numerical control device 20.
Connected to the liquid pump.

The other liquid B is made of a raw material such as sodium silicate and is sent from the raw material tank 10 to the cushion tank 9. This tank 9 is in communication with a B liquid pump in the tank 20.

In the pump, the discharged liquid A is sent to the flow rate transmitter 11.
a, passes through a pipe 25 via an electric valve 11b and a pressure transmitter 11c, passes through an electric valve 14 operated by an electric valve operation panel 27, and furthermore, an electric valve 16a and a pressure transmitter 16b controlled by an underground control panel 24; through the valve 17 at the tip,
It is sent to the injection nozzle 40. Similarly, for liquid B, the flow rate transmitter 12a, the electric valve 12b, the pressure transmitter 1
2c, pipe 26, electric valves 13 and 15a, and pressure transmitter 15b, the liquid reaches valve 18, and is sent to injection nozzle 40. The injection pressure at this nozzle 40 is detected by a pressure sensor 41. In addition, an earth pressure gauge 30, a face water pressure gauge 31, a density sensor 32, and a PH meter 33 are arranged in the shield machine 100 and the face to detect various data and send it to the central processing unit CPU20a of the control device. The jacking stroke of the shield machine is detected by the sensor 34, and information from the screw conveyor torque meter 35 is also sent to the control device to judge these conditions and perform more precise control.

In the control device 20, central processing units 20a, A
Mainly the liquid pump PA and B liquid pump PB, the processing equipment and equipment for processing information from various sensors are housed. The system is mainly controlled by a ground control panel 22, and a recorder 21 is attached to the ground control panel 22.

The ground control panel 22 communicates with the underground control panel 24 and can also be operated by a local controller 23.
An electric valve control panel 27 is appropriately provided in the middle of the pipeline. Emergency stop and enable.

[Operation of the System] Next, the operation of the present system will be explained with reference to FIGS. 2 and 3.

The present invention is characterized in that the pump that supplies the backfilling material is centrally controlled by a central processing unit integrated with the pump, and as input information for this control, a pressure transmitter placed near the injection port is used. The actual injection pressure of liquids A and B sent from the container is mainly used. In addition, secondary control information includes earth pressure at the face, water pressure, density, water pH,
Various information such as the jack stroke of the shield machine and the torque of the screw conveyor is sent to the central processing unit for more complete control.

FIG. 2 shows the relationship between the control device and various sensors.
It is equipped with various controllers, including pump PA for liquid A and liquid A, and pump PB for liquid B.

The central processing unit 20a receives pressure signals from pressure transmitters 11c, 12c, 15b, 16b, etc. arranged in the pipeline, and responds to the pressure signals from the pumps PA,
Control PB.

In addition, the soil pressure from the soil pressure gauge 30 installed at the face and the soil density information from the density sensor 32 are used to judge the soil quality in the vicinity where the backfilling material is currently being injected, and the information from the water pressure gauge 31 The water pressure and PH level information from the PH meter 33 will be used to judge the condition of the spring water.

In addition, information such as the jack stroke, screw conveyor, and torque serves as information for determining the ground, soil quality, and the occurrence of tail voids. Each piece of information is sent to the central processing unit 20a as necessary to enable more precise control.

Next, each step of this backfilling material injection method will be explained with reference to the flowchart shown in FIG.

The system is started and, in step S1, the central processing unit and pump are activated to begin injection. At this time, the mixing ratio of liquid A and liquid B is set in advance.
At the same time as the start of injection, the injection pressure is checked at regular intervals (step S2). As long as the injection pressure P does not reach the preset first predetermined pressure P1, injection continues at the flow rate Q1 corresponding to P1 (step S3). When the injection progresses and the injection pressure exceeds the first predetermined pressure P1, the injection proceeds to a higher second predetermined pressure P2 (step S4). Until P2, the flow rate remains at the second predetermined flow rate. The process changes to Q2, and injection continues until the injection pressure reaches P2 (step S5). When the injection pressure reaches P2, it is determined whether the primary injection is completed (step S6). This first injection is the injection amount of backfill material that is predicted in advance depending on the soil quality and the number of tail voids, etc., and the primary injection is completed when the predetermined injection amount is injected as planned at the predetermined injection pressure. Consider it completed. The predetermined combination of pressure and flow rate is P1, Q2 in the above flow.
Although two sets, P2 and Q2, are shown, three or more sets may be set as necessary. When the injection is complete, stop the injection (step S7) and start the timer (step S7).
S8). After interrupting the injection for a certain period of time, the injection is restarted (step S9) and a second injection is performed. This secondary injection is to compensate for the backfilling material that was injected in the first injection being absorbed into the soil or for gaps not being completely filled. Upon completion of the injection (step S10). Near the completion of the secondary injection, the injection pressure becomes high, and in some cases, the pressure may rise abnormally. The presence or absence of this abnormality is determined in step S11, and if an abnormality occurs, both electric valves 15a and 16a are closed to instantly stop both liquids A and B, and pumps PA and PB are simultaneously stopped (step S12).

In normal cases, first close the B liquid side (step
S13), the timer is activated (step S14), and after a certain period of time has elapsed, the A liquid side is closed (step S15) to complete the injection. This procedure is to prevent the backing material from forming a lump near the injection port when both liquids A and B are stopped at the same time. Each data in this type of process is recorded on a recorder 21 attached to the ground control panel 22, and by reading this data, the status of backfilling material injection can be deciphered. Further, the operation of the system can be similarly controlled not only by the control panel 22 on the ground but also by the underground control panel 24.

As described above, according to the present invention, the following excellent effects are achieved.

(1) The central control device injects the backfilling material by selecting a plurality of predetermined injection pressures and injection flow rates based on data, so the work is easy.

(2) Since the secondary injection is performed after the primary injection, the injection work can be carried out sufficiently.

(3) If the detected pressure is higher than the predetermined pressure, it is determined that sufficient backfilling material has been injected.
There will be no excess or deficiency.

(4) Even if construction conditions change, the injection status can be known just by detecting pressure.

(5) Precise control and no waste.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a backfill injection system to which the present invention is applied, FIG. 2 is an explanatory diagram showing a control system, and FIG. 3 is a flowchart showing each step of the backfill injection method. 1, 2, 3...Liquid A raw material silo, 5...Water tank, 6...Mixer, 7...Asia Star, 10
... Sodium silicate tank, 11a, 12a ... Flow rate transmitter, 11b, 12b, 13, 14, 15
a, 16a...Electric valve, 11c, 12c, 1
5b, 16b...pressure transmitter, 20...control device, 20a...central processing unit, 25...liquid A pipe, 26...liquid B pipe, 100...shield machine, 110...screw conveyor, 120 …
...Segment, 140...Tail void, PA...
...A liquid pump, PB...B liquid pump.

Claims (1)

[Claims] 1 When excavating a tunnel using the shield method, in the backfilling method in which liquid backfilling material is injected with a pump between the segment installed at the rear of the excavator and the ground, the injection pressure is increased at regular intervals. The system detects, sets in advance the relationship between multiple sets of injection pressure and injection flow rate based on data on the geology of the ground to be excavated, and controls the injection pump by the central processing unit according to the relationship to perform primary injection. A backfill injection method characterized in that injection is interrupted when the injection pressure reaches a predetermined pressure, and after a certain period of time, secondary injection is performed at a predetermined injection pressure and injection flow rate.