JP2007162403A - Invert subgrade construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an invert subgrade construction method suitable for the shield jacking excavation of a long-distance large-bore tunnel even in the sediment ground containing gravel in the tunnel excavated ground, taking out working face excavated mud to the ground by a conventional method, backfilling part of the taken-out mud in a batch manner into an invert part to form a strong subgrade with uniform density. <P>SOLUTION: This invert subgrade construction method is characterized in that solidifying agents 5, 6 are added in discharged excavated mud 4 for primary reforming to take out the mud onto the ground, and then secondary reforming is performed to backfill the mud into the invert part 8 to form the subgrade 9 in tunnel excavation work wherein the working face 2 of the tunnel 1 is jacked by a mud pressurizing shield machine 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to invert roadbed construction in a face propulsion method using a mud pressure shield machine.

  Conventionally, a method for reusing excavated sediment in a muddy water shield method for tunnels has been developed (for example, Patent Document 1).

In this method, the primary treatment that separates the sand from wastewater, the secondary treatment that separates clay and silt from the excess wastewater, and the tertiary that adjusts the excess water separated by the secondary treatment. Have a processing plant,
To properly mix the treated soil fed from the secondary treatment plant and the treated water fed from the tertiary treatment plant, add the additive to make backfill material such as invert mortar, and transport this to the point of use Therefore, the backfilling material requires fluidity to flow the piping, and it is difficult to backfill the invert part and roll it to form the roadbed material.

Therefore, a tunnel is excavated with a cutter while stabilizing the outer peripheral part of the tunnel with mud pressure, and a mechanism for excavating with a cutter in advance while stabilizing the center of the face with mud pressure,
A method has been developed in which a solidifying agent is mixed with excavation mud discharged from the center of a face and backfilled in an invert portion (for example, Patent Document 2).

  However, the mud hydraulic excavation mechanism on the outer periphery of the face is superior in that the drilling mud can be discharged to the ground at once by a mud pipe (pipe) and pump, but if the excavation ground contains gravel, the pipe may be clogged with gravel. Yes, equipment is complicated and difficult to use.

  In the mud pressure type shield propulsion drilling in the center of the face, it is difficult to keep the mixing ratio between the amount of drilling mud (raw mud) generated during propulsion and the amount of added cement continuously. Unevenness in concentration is likely to occur, and it has been difficult to backfill earth and sand with a constant concentration (or water content) continuously in the invert part to form a road bed with a constant strength.

JP-A-8-105290 JP-A-2005-139840

  The present invention is suitable for shield-promoted excavation of long-distance, large-diameter tunnels, even for earth-and-sand grounds containing gravel in the tunnel excavation ground. The purpose is to backfill the next reforming invert part batch-wise and easily form a roadbed.

In order to achieve the above object, the present invention is a tunnel excavator that first pushes the face of a tunnel with a mud pressure shield machine, and adds a solidifying agent to the discharged excavation mud to perform primary reforming and carry it to the ground. Invert roadbed construction method characterized by secondary reforming and backfilling in the invert part to form the roadbed,
Second, the invert roadbed construction method according to the first aspect of the present invention, wherein the entire amount of the excavated mud is modified with a solidifying material, and a part thereof is secondarily modified to be improved soil.
Thirdly, the invert road bed construction method according to the first or second invention, wherein the inverted excavation mud other than the invert part backfill material is carried out to the ground by a conventional method,
Consists of.

  Therefore, the mud pressure shield machine that excavates the face of the tunnel is propelled for a certain distance by a cylinder having the receiving surface at the tip of the segment that has been primary lining on the inner periphery of the tunnel, and the face is supported while being pressed with mud. After propelling the entire surface, the cylinder is removed or contracted, and further segments are added along the inner circumference of the shield tube, and primary lining is performed.

  Along with the promotion of the shield machine, the mixed mud of excavated soil and press-in mud is discharged onto the belt conveyor in the tunnel by a screw conveyor, transported to the ground by a conventional method, and transported as waste by a truck.

  When being transported to the ground, the mixed mud is accommodated in a mixer in the tunnel and the solidified material is mixed in a batch manner. The mixed mud is primarily reformed and then transported to the ground by a conventional method.

  Part of the mixed mud that has undergone primary reforming is further metered into the mixer by a conveyor without being transported to the ground, and further solidified material is metered into the mixer and stirred and mixed in a batch manner for secondary reforming. Is done.

  The mud thus modified and improved in a batch manner is backfilled by the belt conveyor in the invert portion on the segment closest to the face to form a road bed.

  Since the present invention is configured as described above, not only can long-distance large-diameter tunnels be shield-promoted excavated in the earth and sand ground, but a part of the excavated mud is reformed in the invert part in a batch manner to easily form the roadbed. There is a possible effect.

  The entire face of the face 2 of the large-diameter tunnel 1 (10 to 15 mφ) is propelled by a mud pressure shield machine 3. The propulsion is performed by pressing the outer periphery of the partition wall 13 of the excavation chamber 12 of the machine 3 toward the face 2 with a plurality of cylinders 14.

  The cylinder 14 is disposed between the distal end surface 16 ′ of the segment 16 covering the excavated ground 15 and the partition wall 13, and the shield machine 3 is propelled for the length of the unit segment 16 to be attached to the inner periphery of the shield steel 17. The arcuate segment 16 is mounted along the primary lining, and a filler 18 is injected between the ground 15 and the outer periphery of the segment 16.

A rotating shaft 19 is provided at the center of the partition wall 13, and a face cutter 20 is provided at the tip thereof. The cutter 20 is provided with a rearward stirring blade 21, and mud 22 passes through the rotating shaft 19 and the cutter 20 A mud chamber (excavation chamber 12) is formed between the face 2 and the partition wall 13,
A belt in which the excavated mud 4 is formed by mixing the cut excavated sand and the injected mud 22 with the stirring blade 21 by the cutter 20 to form the excavated mud 4 and the screw conveyor 24 opened at the lower part of the bulkhead 13. It is discharged on the conveyor 25 by the propulsion of the shield machine 3, and this operation is repeated for each operation of the cylinder 14 to propel the face 2 (FIG. 1).

  The excavated mud 4 by the conveyor 25 is charged batchwise into the mixer 26 shown in FIG. 2, and at the same time, the gypsum-based solidified material 6 is charged batchwise from the solidified material tank 6 ′ described later, mixed and stirred, and subjected to primary reforming, By a conventional method, about three-quarters of the total amount is carried out to the hopper 29 on the ground 10 by the bucket elevator 27 or other means, and is discarded to the treatment site by the truck 30.

  About one-fourth of the total amount is transferred from the mixer 26 to the measuring mixer 32 in a batch manner as shown in FIGS. 2 (A), (B), FIG. 3 and FIG.

As shown in FIG. 6, the metering mixer 32 is supported by a machine frame 33 via a load cell 34, and the reverse belt conveyor 31 and its screw conveyor 31 ′, a cement-based solidifying material metering screw conveyor 36 are contained in the mixer 32. The above-mentioned primary modified mud 23, cement or cement-based solidified material 35 is fed batchwise by
The cement-based solidified material is weighed and supplied to the mixer 32 according to a signal from a comparison calculation unit between the measured value of the load cell 34 and the set value of the cement-based solidified material 35, and is stirred and mixed by the mixer 32 for quantitative stability. Modified soil (improved soil) 7 can be used.

  Of course, the viscosity and density of the primary modified mud 23 put into the measuring mixer 32 by the reverse conveyor 31 are measured in advance, and the unit weight and viscosity (viscosity) are substantially constant.

  The input amount of the mud 23 is about half of the capacity of the machine box 32 ′, and the amount of input mud by the load cell 34 is detected.

  In this way, the weight detection value of the modified mud (raw mud) 23 is compared with the set value in the setting unit of the control unit by the signal from the load cell 34, stored, and fed back to stop the reverse conveyor 31. However, the stirring operation by the horizontal rotation shafts 37 and 37 continues (FIGS. 6 and 7).

  When the detected value measured by the load cell 34 reaches the weight setting value of the modified mud 23, the weight ratio of the cement-based solidified material is compared and calculated by a comparison calculator, and the signal is input by the signal. The cement-type solidifying material weighing conveyor 36 (screw conveyor) is started, and the input amount is weighed by the measuring device 28, and is charged into the machine box 32 'to automatically stop.

The above charging can be performed simultaneously or at different times, and the stirring operation is continued even during the charging, and the mud 23 is stirred and mixed with the cement-based solidified material, while the cement-based solidified material reacts with moisture and sets. Harden.
Further, the soil particles aggregated by the fixation and curing of water accompanying mixing are aggregated to form large cured particles including the soil particles.

  The cylinder 14 of the shield machine 3 operates with the elapse of time set in advance by the mixing test, and the convex arc opening / closing plate 38 ′ of the convex arc bottom surface 38 shown in FIG. It is discharged downward as recycled soil (secondary modified mud) 7 in 32 ′ and is fed back to the face 2 side by the reverse conveyor 37.

  The cement solidified material in a set ratio with respect to the weight of the modified mud 23 charged in the mixer 32 is accurately charged and stirred, and the improved soil 7 rich in quantitative stability and uniformity in quality is fed back in a batch manner. To the invert section 8.

  Further, water can be supplied to the mixture in the mixer 32 as necessary, or dry air (gas) can be supplied to adjust the quality and increase the reaction rate.

  The modified mud soil (improved soil 7) fed back toward the face 2 is backfilled in the invert portion 8 on the segment 16 immediately after the shield machine 3 and is filled with a compacting machine (not shown). ) And the road bed 9 is formed. The compacting machine has functions such as a vibration roller, a tire roller, and a finisher, and has a structure that can be processed automatically. Therefore, the sleeper 40 (FIG. 5) is laid directly on the road floor 9 without requiring the long H-shaped steel 38 (10 to 15 m) shown in FIG. 9 (A) and the concrete roadbed 39 shown in (B). Rails can be laid back and forth to supply equipment and other materials to the shield machine 3.

  In FIG. 6, the reference numeral 40 indicates a recycled soil discharge hopper, 41 is a mud (raw mud) input hopper, 42 is a cement-based solidification material input hopper, 43 in FIG. 1 is a weir plate of the invert section 8, and 44 is its stay. is there.

It is a side view of the invert part construction state of this invention. (A) The figure is a side view of the excavated primary reforming mud being carried out on the ground, and (b) is a rear view taken along the line AA in FIG. It is a side view of a secondary reforming mud formation mixer. (A) (b) (c) (d) The figure is a side view of the facet propulsion state. It is a front view of an invert part roadbed formation state. It is a side view of a secondary improvement mud formation mixer. It is a longitudinal cross-sectional view by FIG. 6B-B line. It is a side view which shows the invert subgrade construction method by the conventional outer periphery muddy water and center part mud excavation shield machine. (A) (b) is a front view of a conventional invert portion roadbed formation state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tunnel 2 Face 3 Mud pressure shield machine 4 Discharged excavation mud 5, 6 Additive (solidification material)
7 improved soil 8 invert section 9 roadbed 10 ground

Claims (3)

  A tunnel excavator that pushes the tunnel face with a mud pressure shield machine, adds a solidifying agent to the discharged excavated mud, performs primary reforming, transports it to the ground, and then secondary reforms to bury it in the invert part. Invert road bed construction method characterized by returning and forming the road bed.   The invert subgrade construction method according to claim 1, wherein the entire amount of the excavated mud is reformed with a solidifying material, and a part thereof is secondarily reformed to obtain improved soil.   The invert roadbed construction method according to claim 1 or 2, wherein the excavated mud other than the invert part backfill material is carried out to the ground by a conventional method.

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