JP5491562B2 - Open shield construction method for sand ground - Google Patents

Description

  The present invention relates to an open shield construction method for constructing underground structures such as water and sewage systems and underground passages in an urban area and corresponding to sand ground.

  The open shield method is a rational method that utilizes the advantages of the open cut method (open cut method) and the shield method, and the outline of the open shield machine 1 used in this open shield method is as shown in FIG. The front, rear, and top surfaces of the plate 1a and the bottom plate 1b connected to the side wall plates 1a are opened, the front ends of the side wall plate 1a and the bottom plate 1b are formed as blade edges 11, and the center of the side wall plate 1a is formed. Alternatively, the shield jacks 2 are arranged side by side in the vertical direction near the rear end. In the figure, 3 indicates a partition wall.

  The open shield method to be constructed using the open shield machine 1 is not shown in the figure, but the open shield machine 1 is installed in the start pit, the shield jack 2 of the open shield machine 1 is extended, and the inside of the start mine is The open shield machine 1 is advanced by taking the reaction force against the reaction wall, the first concrete box 4 forming the underground structure is suspended from above, and the shield is shrunk in the tail part 1c of the open shield machine 1 Set behind jack 2. A strut is disposed between the shield jack 2 and the reaction wall to adjust the distance appropriately.

  In addition, the start pit is made up of a retaining wall, and in order to start the open shield machine 1, a part of this retaining wall is mirror-cut. If necessary, the ground is improved at the front part of the starting pit by chemical injection or the like. Sometimes it is left.

  Excavator 9 such as an excavator excavates and removes soil from the front or top surface of open shield machine 1. Simultaneously with or after this earth removal step, the shield jack 2 is extended to advance the open shield machine 1. In the case of this forward process, a press bar 8 made of a frame body made of box steel or mold steel is disposed in front of the concrete box 4, and the open shield machine 1 reacts from the concrete box 4 set rearward. Take.

  Then, the second concrete box 4 is suspended in the tail part 1 c of the open shield machine 1 in front of the first concrete box 4. Thereafter, the same soil removal process, advance process, and setting process of the concrete box 4 are repeated as appropriate, and the concrete boxes 4 are sequentially left in the ground in line with the advancement of the open shield machine 1, and further this concrete box. Put backfill 5 on the upper surface of 4.

  When the concrete box 4 is suspended in the tail part 1c of the open shield machine 1, a height adjusting material 7 such as a concrete block is disposed under the concrete box 4 and opened in the tail part 1c. The back injection material 6 is primarily injected into the gap between the inside of the shield machine 1 and the bottom plate 1b below the bottom of the concrete box 4, and further, the open shield machine 1 is advanced, and the bottom plate 1b is formed here after the advance. The back-filling material 6 is further injected into the gap and the left and right sides of the concrete box 4 to complete the filling of the back-filling material.

  In this way, if the open shield machine 1 reaches the reaching mine, it is removed and the construction is completed.

  In such an open shield construction method, as described above, the concrete box 4 is left in the ground in a column as the open shield machine 1 advances, and the concrete box 4 is suspended in the tail portion 1c of the open shield machine 1. As the open shield machine 1 moves forward, it leaves the tail portion 1c and remains in the ground. The open shield machine 1 takes a reaction force on the concrete box 4 left in the ground in this way. Advance.

  The concrete box 4 is made of reinforced concrete, and includes a left side plate 4a, a right side plate 4b, an upper floor plate 4c, and a lower floor plate 4d as shown in FIG.

By the way, as shown in the following patent document, the body of the open shield machine 1 is divided into a plurality of parts in the front-rear direction (two divisions) so that the direction can be corrected so that it can be applied to curve construction, and is shown in FIG. In this way, the front part 1d having the blade edge 11 at the tip and the tail part 1c on which the middle part 1e and the concrete box 4 are suspended are divided.
JP 2010-242374 A

  A shield jack 2 is disposed at the left and right positions of the middle part 1e of the front part of the tail part 1c from which the concrete box 4 is suspended. The jack is folded at the right and left positions of the rear part of the front part 1d in front of the middle part 1e. 14, and the open shield machine 1 is advanced by the shield jack 2 by changing the stroke difference between the right and left bent jacks 14.

  In the figure, 13 is a slide jack disposed on the front portion 1d, and 15 is a slide earth retaining plate.

  To explain the operation, in order to install the concrete box 4 on the tail 1c, the open shield machine 1 is dug by one box of the concrete box 4 using the shield jack 2.

  The concrete box 4 is suspended and installed in the tail part 1c as described above, and the back-filling injection material 6 is primarily injected into the gap between the inside of the tail part 1c and the outside of the installed concrete box 4.

  Thereafter, the open shield machine 1 is further advanced. The back injection material 6 is secondarily injected into the tail void (corresponding to the shield machine plate thickness) generated by this advance.

  By the way, the sand ground has a high groundwater level, and the sandy soil layer of the sandy soil layer with a high groundwater level easily collapses during construction, and construction is difficult. In order to maintain the stability of the face at the time of construction, it is necessary to improve the ground such as the groundwater level lowering method using well points, etc. and the chemical injection method as an auxiliary method, which is expensive, and the open shield method is used. Since it is necessary to perform an auxiliary method before construction, the construction period becomes longer.

  The present invention eliminates the inconvenience of the conventional example, and in the open shield method, it is possible to prevent the collapse of the natural ground without performing the groundwater level lowering method or the ground improvement work due to the well point etc. in the sand layer, etc. The object is to provide an open shield method for sand ground that reduces the cost of the box and improves the laying accuracy.

In order to achieve the above-mentioned object, the present invention as claimed in claim 1 includes a step of excavating and discharging soil in front of the front or upper surface opening of the open shield machine using an open shield machine, and a reaction force to the concrete box. The process of digging the shield machine and the process of hanging and setting a new concrete box from the top to the tail part of the rear of the shield jack shrunk in the jack part of the shield machine are repeated as necessary to sequentially form the concrete box. In the open shield method embedded in a column, the open shield machine has the front, middle, and tail parts as the first, second, and third divided blocks, and has a cutting edge at the front end. , the side, partition walls come together, the left and right side walls inside shall diameter the entire width in the tapered front portion and bromide partition provided at its deepest portion A face propulsion jack is provided between the parts, a middle-folded jack is provided between the middle part and the tail part, and a shield jack is provided at the tail part. The shield machine is advanced after the front part is advanced, and then the middle part and tail part are advanced. The front part is propelled by the face propulsion jack, inserted into the front ground, and compacted, and the inside of the front part is excavated by an excavator such as a backhoe. After the front part is advanced, the face propulsion jack is reduced and the shield jack is extended. And the middle part and the tail part are advanced.

  According to the present invention as set forth in claim 1, the ground in the front part of the front partition wall is excavated and excavated in a state where the front part is always inserted into the face of the sandy soil layer having a high groundwater level, and the partition wall Since it is in a state where it is pressed toward the front natural ground, the loose face of the face is not extended to the natural ground at the front end of the front part, and the stability of the natural ground due to the well point or ground improvement becomes unnecessary.

  Also, since shield machine excavation always advances the front part and then propels the main body (middle part and tail part), the reaction force to the laying box is reduced, and the box cost is reduced and the laying accuracy is increased. .

Furthermore, while excavating the front of the bulkhead with a backhoe etc. with the front part inserted into the face of the sandy soil layer with a high groundwater level, the face propulsion jack is extended to further move the front part to the front ground. Since it is propelled forward, the ground of the excavated and earthed part in front of the front bulkhead will be pushed into the part where the entire width is reduced by tapering the left and right side walls inside the front part. The natural mountain is consolidated by the bulkhead at the part, and the natural mountain in the front part is not loose and can always maintain a stable state.

  The gist of the present invention described in claim 2 is that the shield machine is dug by inserting the front part into the front ground with a face propulsion jack at a ground collapse angle of 45 ° or more and consolidating the bulkhead and the side part. It is.

  According to the second aspect of the present invention, the partition wall side is excavated and discharged from the 45 ° collapse line (α in FIG. 2) in the front portion by the backhoe or the like in the front portion inserted into the front face mountain. The lap between the side plate and the face hill is sufficiently long with both side plates of the front part always inserted into the natural ground side from the 45 ° collapse line, and the side plate is not divided, so even in sandy ground with underground water level The front part has higher water-stopping performance than the conventional type. Therefore, even in sandy ground with high groundwater, the Mt.

  As described above, the open shield method for sand ground of the present invention can prevent the collapse of natural ground without performing groundwater lowering method and ground improvement work such as well points with sand layers, etc. Since the propulsive reaction force can be reduced, the cost of the box is reduced and the laying accuracy is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a cross-sectional plan view showing an embodiment of an open shield method for sand ground according to the present invention, FIG. 2 is a longitudinal side view of the same, and FIG. 3 is a cross-sectional view taken along line AA of FIG. The open shield machine used in the invention will be described.

  In the open shield machine 1, the airframe is made into first, second, and third divided body blocks that become the front portion 1d, the middle portion 1e, and the tail portion 1c, and these are fitted.

  The open shield machine 1 comprising the front part 1d, the middle part 1e and the tail part 1c as a whole has an open front, rear and top surface comprising left and right side wall plates and a bottom plate connected to the side wall plates. .

  The front portion 1d is formed with the tip as a blade edge 11, and one end of a face propulsion jack 16 is axially attached to the side wall plate and near the center or rear end of the bottom plate.

  This face propulsion jack 16 is arranged side by side in the vertical and horizontal directions toward the rear, and is a pin jack that is pivotally attached to the end, and the multi-end is a shaft near the tip or center of the side wall plate and bottom plate of the middle portion 1e. By wearing, it is disposed between the front part 1d and the middle part 1e.

  The front part 1d has a tapered inner side on the left and right side walls, and the entire width is reduced. The bottom plate also rises with the tip part tapered and becomes flat as it is, and the inner part is smaller than the opening part. The front partition wall 17 is provided at the deepest part.

  The face propulsion jack 16 can be provided by utilizing the space between the inner wall and the outer shell of the front portion 1d whose space is reduced in diameter.

  As shown in FIG. 3, the middle portion 1e has a tip portion that is slightly smaller than the front portion 1d inserted into the front portion 1d, and a water stop rubber 18 is provided on the front portion 1d side, which is provided on the outer periphery of the middle portion 1e. Make contact.

  A middle-folded jack 19 is provided in the rear half of the middle part 1e so as to face the rear, and this is applied to the front end of the tail part 1c. The middle folding jack 19 is disposed between the middle portion 1e and the tail portion 1c. The middle folding jack 19 is arranged in parallel with a gap along the left and right side walls of the middle portion 1e. The middle part 1e is refracted with respect to the tail part 1c by extending it longer than the others.

  A tail partition wall 20 is provided at the front end of the tail portion 1c, and a wire brush 21 is provided between the rear half of the middle portion 1e and the front end of the tail portion 1c fitted therein.

  The tail part 1c has a jack placement part in the first half and a box installation part in which the concrete box 4 is suspended. The shield jack 2 is arranged in the jack arrangement portion of the tail portion 1c so as to be arranged rearward and upward.

  In the figure, 22 is a press bar, 23 is a water stop bar, and these are made of steel such as H-shaped steel. The whole is framed in a U-shape.

  The press bar 22 and the water stop bar 23 are arranged to be suspended by a crane or the like at the front end when the concrete box 4 is suspended from the tail portion 1c, and the press bar 22 receives the pressing force of the shield jack 2. Make.

  Next, the sand shield corresponding open sand construction method of the present invention performed using the above open shield machine 1 will be described. 5 to 7 are cross-sectional plan views showing the respective steps of the present invention, and FIGS. 8 to 10 are cross-sectional plan views of the same. First, as shown in FIGS. 5 and 8, box installation and primary injection are performed.

  The open shield machine 1 is after the existing concrete box 4 has been advanced in reaction force, the concrete box 4 is suspended from the tail part 1c, and the concrete box from the inside of the open shield machine 1 in the tail part 1c. The back injection material 6 is primarily injected into the gap between the bottom plate 4 and the bottom plate.

  Next, the front portion 1 d is propelled by the face propulsion jack 16. The forward movement of the front portion 1 d by the face propulsion jack 16 compacts the earth and sand at the front partition wall 17.

  The front part 1d is moved forward by a face propulsion jack 16 into a natural ground at a natural ground collapse angle of 45 ° or more, and is compacted by a partition wall and a side part.

  Then, the inside of the face protected by the front portion 1d is excavated by an excavator 9 such as a backhoe. (See Figure 4)

  Next, the reduction of the face propulsion jack 16 and the extension of the shield jack 2 are performed simultaneously, and the middle portion 1e and the tail portion 1c are dug. The middle concrete section 1e and the tail section 1c are propelled together by the shield jack 2 using the columned concrete boxes 4 as a reaction force.

  The middle portion 1e and the tail portion 1c are advanced in the same manner as described above, and the middle portion 1e is first advanced by the folding jack 19 and then the tail portion 1c is advanced by the shield jack 2. It may be divided into two stages.

  In the case of curved construction, the middle portion 1e is refracted with respect to the tail portion 1c by the bent jack 19.

  Thereafter, the above excavation work is repeated, and after completion of excavation for one box, the process returns to the first step.

It is a cross-sectional top view which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a vertical side view which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is the sectional view on the AA line of FIG. It is a vertical side view of the state excavating with the excavator which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a cross-sectional top view of the 1st process which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a cross-sectional top view of the 2nd process which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a cross-sectional top view of the 3rd process which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a vertical side view of the 1st process which shows one Embodiment of the sand shield corresponding open sand construction method of the present invention. It is a vertical side view of the 2nd process which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a vertical side view of the 3rd process which shows one Embodiment of the sand shield corresponding open sand construction method of this invention. It is a vertical side view which shows the outline of an open shield construction method. It is a perspective view of a concrete box. It is a vertical side view which shows a prior art example.

DESCRIPTION OF SYMBOLS 1 Open shield machine 1a Side wall board 1b Bottom board 1c Tail part 1d Front part 1e Middle part 2 Shield jack 3 Bulkhead 4 Concrete box 4a Left side board 4b Right side board 4c Upper floor board 4d Lower floor board 5 Backfill soil 6 Back injection material 7 High Length adjusting material 8 Press bar 9 Excavator 10 Opening 11 Cutting edge 12 Tail side plate 13 Slide jack 14 Middle folding jack 15 Slide retaining plate 16 Face pushing jack 17 Front bulkhead 18 Water blocking rubber 19 Middle folding jack 20 Tail bulkhead 21 Wire brush 22 Press bar 23 Water stop bar

Claims (2)

Using an open shield machine, the process of excavating and discharging the soil in front of the front or top opening of the open shield machine, the process of digging the shield machine using the reaction force of the concrete box, and the jack part of the shield machine In the open shield method of burying concrete boxes in series one after another by repeating the process of hanging and setting a new concrete box from the top to the tail part behind the shield jack shrunk in
The open shield machine is the first, second, and third divided body blocks that become the front part, middle part, and tail part.
It has a cutting edge at the front end, and the side and partition walls are integrated, and the inside of the left and right side walls is tapered to reduce the overall width. The partition wall is propelled between the front part and middle part provided at the deepest part. The jack is folded between the middle part and the tail part, and the shield part is provided on the tail part.
In the shield machine, the middle part and the tail part are dug after moving forward in the front part.
With the face propulsion jack, the front part is propelled, inserted into the front ground, consolidated, and the inside of the front part is excavated with an excavator such as a backhoe, and after moving forward, the face propulsion jack is reduced and the shield jack is extended. Open shield construction method for sand ground, which is performed simultaneously and the middle part and tail part are advanced.   The open shield construction method for sand ground according to claim 1, wherein the shield machine is dug by inserting a front portion into a front ground with a face propulsion jack at a ground collapse angle of 45 ° or more and compacting at a partition wall and a side portion.

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