JP2005119057A - Manufacturing method of segment for shield tunnel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a manufacturing method of a segment for a shield tunnel to enhance not only production efficiency but also the quality of a product. <P>SOLUTION: A form 10 of the segments corresponding to one circumference of a circle is integrally formed in a state that the cylindrical shaft thereof is made vertical and end frames 13 are alternately mounted on the segments 1 adjacent to each other in a circumferential direction to cast concrete in the end frames. After concrete is cured, the end frames 13 are detached and the end surfaces of the cured concrete segments are used as a form to cast concrete of residual segments. After concrete is cured, concrete is demolded to be separated into a plurality of segments. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a shield tunnel segment, and more particularly to a technique for manufacturing a segment in a posture such that a cylindrical axis is vertical.

  When manufacturing shield tunnel segments, prepare molds for placing individual arc plate segment concrete for the segment type of one divided circle, and place these dedicated molds flat on the work place. It was manufactured by placing concrete in it.

  FIG. 3A to FIG. 3E are explanatory views showing such a manufacturing process. As shown in FIG. 3A, a mold 51 forming an arc plate segment is placed in a flat plate shape on a floor with an arc projecting upward.

  As shown in FIG. 3 (a), the mold 51 includes an arcuate side frame 52, a rectangular end frame 53, and a curved plate-like bottom plate 58. The side frame 52 has an inter-ring joint (tunnel). An axial joint) 54 is attached, and a tenon concave portion 55 and a tenon convex portion 56 are provided on the inner side of the end frame 53 as an example of an inter-piece joint (tunnel circumferential joint).

  As shown in FIG. 3 (b), concrete 61 is placed in the mold 51 while applying the upper lid 57, and as shown in FIG. 3 (c), the concrete placement is continued while sequentially covering the upper surface with the upper lid 57. To do.

  Next, as shown in FIG. 3D, the upper cover 57 is removed, and the surface 63 of the concrete in the mold 51 is smoothed. After the concrete is hardened, the mold is removed to form segments 65 for each sheet as shown in FIG.

  In such a conventional technology, it is necessary to make the joints between the segments highly precise mating surfaces from the viewpoint of preventing chipping and breakage due to point contact between concrete after assembling the segments in the tunnel and ensuring water tightness. It is. The dimensional accuracy is required to be 1.0 mm or less, preferably 0.5 mm or less, between the pieces (the circumferential seam of the segments) and between the rings (the tunnel axial direction seam of the segments). Since both the ring surface and the piece surface require higher plane accuracy, a mold with high manufacturing accuracy is required. As a result, mold manufacturing costs are expensive. Further, the conventional technique has a problem in that it is necessary to secure a wide working place because individual molds are arranged in a planar manner for each segment.

  It is an object of the present invention to improve the conventional method for manufacturing a shield tunnel segment and improve the production efficiency and the quality of the product.

  The present invention has been made to solve the above problems, and is characterized by taking the following technical means. That is, when manufacturing a shield tunnel segment in which the circumferential direction is divided into a plurality of parts, the present invention forms the frame of the segment for one circumference integrally with the cylindrical axis vertical, and in the circumferential direction. Attaching a frame to every other adjacent segment and placing concrete in it. After hardening the concrete, remove the frame and bring it into contact with the surface of the hardened concrete segment. It is a manufacturing method of the segment for shield tunnels characterized by installing, demolding after hardening, and isolate | separating into each division segment.

  Further, in the case of manufacturing a segment having an odd number of the plurality of divisions, the following process may be added in the middle of the manufacturing method. That is, a step of manufacturing one of the two remaining segments among the remaining segments by bringing one end face into contact with the hardened concrete and attaching the end face frame to the other end face is added. Thereafter, the remaining segment of concrete is cast.

  According to the present invention, since one circle is used as one mold, it is not necessary to prepare individual molds for each segment one by one. In addition, it is possible to easily improve the alignment accuracy of the circumferential seams of the segments without increasing the processing accuracy of the formwork, and to greatly reduce the manufacturing cost of the formwork. Play. Since the concrete is placed by placing the entire formwork of the segment for one circumference vertically, there is also an advantage that the manufacturing place may be narrow. In addition, the efficiency of segment manufacturing work can be improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  Fig.1 (a)-FIG.1 (e) are typical process drawings which show embodiment of this invention.

  As shown in FIG. 1 (a), a frame 10 of a segment for one circumference is set with a cylindrical axis vertical. The mold 10 is provided with a mold outer cylinder 11 outside the mold inner cylinder 12, and a space for placing segment concrete is provided between the mold inner and outer cylinders 12, 11, and the concrete enters the mold from above the cylinder. inject. As for a segment, a wife frame is installed in a mold for one circumference so as to form every other segment that is adjacent in the circumferential direction. The frame frame 13 of every other segment where concrete is to be placed is mounted between the inner and outer cylinders 12 and 11 to form the wife surface of the segment, and a reinforcing bar 21 is applied. Concrete is placed all at once in the form of every other segment.

  FIG. 1B shows a state in which concrete is placed in a mold, and after the concrete is hardened, the mold outer cylinder 11 and the end frame 13 are removed. The product segment and top cover remain the same. The end face 24 of the hardened concrete 23 becomes a substitute for the formwork that comes into contact with the end face of every other remaining segment.

  As shown in FIG. 1 (c), the mold outer cylinder 11 is mounted again, and the reinforcing bars 21 are applied, and then the remaining segment of concrete is placed. In other words, the concrete surface of the remaining segment is collectively cast and the form lid 14 is pressed and covered by using the wife surface itself of the product as a concrete frame for the concrete placement of the remaining segment. If the concrete top surface is subjected to mortar with the amount of cure shrinkage adjusted and covered with the mold lid 14, a highly accurate surface can be formed.

  FIG. 1D shows a state in which the mold cover 14, the mold outer cylinder 11 and the inner cylinder 12 are removed, and a concrete segment assembly 31 for one circumference is formed. The face of each segment of the segment assembly 31 is formed with a face that completely coincides with the face of adjacent concrete.

FIG. 1E shows a state where the segments 1 of the segment assembly 31 are separated.
The assembly 31 is separated into individual segments 1.

  The points to be noted in the above steps will be described in detail below.

  First, the concrete placement surface is a joint in the tunnel axial direction of the segment, and a highly accurate surface is required from the viewpoint of water stoppage. It is necessary to avoid hardening shrinkage, bleeding, skin drop, or settlement of the driven surface due to bubbles or poor flatness as much as possible.

In the concrete formulation of the present invention, it is important to suppress curing shrinkage. For this reason, the curing shrinkage is offset by an expansion agent (chemical expansion by ettringite, hydrogen foaming by reaction of aluminum powder, etc.). A desirable addition amount is 15 to 35 kg / m ³ for the swelling agent. If it is less than 15 kg / m ³ , an expansion amount that sufficiently cancels out the contraction amount cannot be obtained. If it exceeds 35 kg / m ³ , the amount of expansion is superior, and high-precision flatness after curing cannot be obtained. Furthermore, it is preferably 20 to 30 kg / m ³ . Aluminum powder is 0.02 to 0.05%, preferably 0.025 to 0.035%, based on cement.

  In order to suppress bleeding and skin peeling, water is trapped by suppressing W / C (water cement ratio), suppressing the amount of water by using an admixture such as a water reducing agent, and increasing the fine content of fine aggregates. A desirable blend is W / C = 34 to 40%. More preferably, it is 34 to 37%. If it is less than 34%, the fluidity is poor and air bubbles are easily taken in. If it exceeds 40%, the bleeding amount is conspicuous.

  The high-performance water reducing agent is 0.5 to 1.5% of cement. More preferably, it is 0.7 to 1.1%. If it is less than 0.5%, the water reduction rate is small, and even if added over 1.5%, the water reduction rate does not improve for the addition amount.

  The fine powder has a fine aggregate FM (Fineness Modulus coarse particle ratio) of 1.1 to 2.3. More preferably 1.2 to 2.0. If the FM is less than 1.1, the fluidity is poor, and if it exceeds 2.3, the moisture trap amount is small and the effect is poor.

  The amount of air in the bubbles is 1.0 to 2.5%. More preferably, it is 1.5 to 2.0%. If it is less than 1.0%, the fluidity is poor, and if it exceeds 2.5%, bubbles are not completely removed from the cured concrete surface, and this is not possible because the flatness is poor.

  Next, processing of the placement surface will be described.

  It is preferable to set the upper lid 14 after smoothing the casting surface after finishing the concrete casting, and after a certain amount of time has passed and the apparent fluidity and bleeding disappear, in order to smooth the casting surface. It is preferable that a mortar such as a non-shrink grout material is spread on the uppermost portion of the driving surface so as to smoothen the surface after curing.

  The vibration is imparted using a table vibrator or a rod-like vibrator as appropriate. It is effective for improving filling properties and reducing bubbles. If the acceleration is too small, the table vibrator has no vibration effect, and if the acceleration is too large, it is not preferable because it encloses bubbles. The magnitude of the acceleration is desirably 1.0 to 3.0 G, more preferably 1.2 to 2.5 G.

  If the concrete driving speed is too high, air bubbles are conspicuous, and it is preferable to drive at a speed as slow as possible. Desirably, it is 5 to 50 cm / min, and more preferably 10 to 20 cm / min.

  When setting the mold, it is the same as before that the segment tunnel axial joint insert is attached to the top lid or bottom plate and the circumferential joint insert of the segment is attached to the end frame.

  The division number of segments in one circle may be an even division or an odd division.

  FIG. 2A to FIG. 2C are plan views showing a construction process in the case where the number of divisions of segments for one circumference is an odd number.

  As shown in FIG. 2 (a), the mold outer cylinder 11 and the mold inner cylinder 12 are assembled, and the concrete frame of the segment 1a is placed by applying the wife frame 13 to the both end faces of the segment 1a to be placed first. After the concrete of the segment 1a is hardened, the mold outer cylinder 11 and each end frame are removed.

  Next, as shown in FIG. 2 (b), one end of the segment 1b where the adjacent two segments 1b and 1c are not formed is attached to the end face adjacent to the other segment 1c, and the end frame 13 is attached to the end face. After the barrel 11 is attached, the concrete of the segments 1b and 1b ′ is placed. The segment 1b 'between the hardened segments 1a is formed in contact with the face of the hardened segment 1a, and one face of the segment 1b is in contact with the face of the segment 1a.

  Next, after the concrete is hardened in the segment 1b, the wife frame 13 is removed, and the remaining segment 1c is placed in the concrete as shown in FIG. 2 (c). Alternatively, the segment 1c may be manufactured in a separate frame, the segment 1c may be incorporated, the segment 1a may be driven, and then 1b and 1b 'may be driven. In addition, when the number of segments for one circumference is an odd number, the number of times of placing concrete is three times as described above. On the other hand, when the number of divisions for one circle is an even division, the number of times of placing the concrete may be two, and it is preferable in terms of productivity that the even division is performed.

  Hereinafter, the present invention will be described with reference to examples.

  A segment obtained by dividing a segment of one circumference having an outer diameter of 2650 mm, a width of 1000 m, and a thickness of 200 mm into four parts was manufactured according to the present invention. The concrete was mixed and the casting conditions were changed to make a prototype by the method of the present invention, and the appearance, temporary assembly results, and the like were evaluated. In addition, the circumferential joint of each segment and the joint in the tunnel axial direction used a steel pin having an outer diameter of 20 mm as a male joint, and an insert fitted thereto as a female joint.

  Table 1 shows the concrete composition. Table 2 shows an example in which the placement conditions were changed. Table 3 shows the results of the product appearance and the temporary assembly results.

  In Tables 1 to 3, Examples 1 to 7 show preferred examples of the present invention, and Reference Examples 1 to 10 are the amount of shrinkage and skin removal in the method of the present invention when some of the individual fine conditions are not appropriate. An example in which some of the joint intervals after provisional assembly were not appropriate was shown.

  In Examples 1-7, since the segment was manufactured under appropriate conditions using the method of the present invention, the total volume of bubbles on the implantation surface, the amount of shrinkage from the implantation surface, and the rate of skin removal all showed appropriate values. In addition, the joint interval between pieces (circumferential direction) after temporary assembly was 0.03 to 0.06 mm, and the joint interval between rings (tunnel axis direction) was 0.08 to 0.11 mm. In particular, the distance between pieces (circumferential direction) has become very small, and the surface adhesion accuracy has been significantly improved.

  In Reference Examples 1 and 2, since the amount of the expansion agent was not appropriate, the contraction (expansion) from the driving surface was not appropriate. In Reference Example 3, the amount of aluminum powder added was small, so the amount of shrinkage was large, and the rate of skin removal also increased. In Reference Example 4, since there was a lot of aluminum powder, the driven surface expanded and the joint interval between the rings (in the tunnel axis direction) increased. In Reference Example 5, since the high-performance water reducing agent was insufficient, the total volume of bubbles on the implantation surface increased. In Reference Example 6, the W / C was too small and the fine aggregate FM was too large, so the fluidity was poor and the total volume of bubbles on the implantation surface increased. On the other hand, in Reference Example 7, the W / C was excessive and the fine aggregate FM was small, so that the total volume of bubbles on the driving surface increased and the skin fell greatly.

  In Reference Example 8, since the concrete driving speed was excessive, the water reduction rate was small, and the total volume of bubbles on the driving surface increased. In Reference Example 9, since the vibration acceleration was too small, the effect of vibration was small, and the amount of contraction from the driving surface was large. In Reference Example 10, the vibration acceleration was excessive, and bubbles were trapped. The total volume of increased.

  In the method of the present invention, it was confirmed that the inter-piece (circumferential direction) seam interval was particularly small and the mutual adhesion performance was good. This is an important advantage that can be obtained from using the wives of a segment that has already been cast as the next cast frame. This indicates that the accuracy of the seam in the circumferential direction of the segment is outstanding regardless of the accuracy of the end frame, and the processing accuracy of the end frame is not necessary, and the cost of manufacturing the segment is greatly reduced. It is connected. Even in the method of the present invention, as shown in Reference Examples 1 to 10, if the manufacturing conditions of the segments are not appropriate, the quality is partially lost, and sufficient management is required.

It is a typical perspective view which shows the process of an Example. It is a typical perspective view which shows the process of an Example. It is a typical perspective view which shows the process of an Example. It is a typical perspective view which shows the process of an Example. It is a typical perspective view which shows the process of an Example. It is a top view which shows the process of an Example. It is a top view which shows the process of an Example. It is a top view which shows the process of an Example. It is a schematic diagram which shows the segment manufacturing process which shows a prior art. It is a schematic diagram which shows the segment manufacturing process which shows a prior art. It is a schematic diagram which shows the segment manufacturing process which shows a prior art. It is a schematic diagram which shows the segment manufacturing process which shows a prior art. It is a schematic diagram which shows the segment manufacturing process which shows a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Segment 10 Mold frame 11 Mold frame outer cylinder 12 Mold frame inner cylinder 13 Mold frame end frame 14 Mold frame lid 21 Reinforcement 23 Hardened concrete 24 Hardened concrete end face 31 Segment assembly 51 Form frame 52 Side frame 53 Wife frame 54 Ring Inter-joint 55 Tenon concave part 56 Tenon convex part 57 Top cover 58 Bottom plate 61 Concrete 62 Concrete placement 63 Concrete surface 65 Segment 66

Claims (2)

  When manufacturing a shield tunnel segment with a plurality of circumferential directions, the form of the segment for one circumference is formed integrally with the cylindrical axis vertical, and every other segment adjacent in the circumferential direction. Attach a girder frame to the concrete and place concrete in it. A method for manufacturing a shield tunnel segment, characterized in that the segment is divided into individual segments.   In manufacturing a segment having an odd number of the plurality of divisions, one of the remaining segments of one of the remaining segments is brought into contact with one end surface of the cured segment, 2. The method for producing a shield tunnel segment according to claim 1, further comprising a step of attaching and manufacturing a wife frame to the other wife surface.

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