JP6441871B2 - Box roof deflection reduction method for box roof method - Google Patents

Description

  The present invention relates to a method for preventing deflection of a box roof used in a box roof construction method in which a box is propelled or towed to construct a railroad and a crossing underpass under a road.

  The box-shaped roof construction method is a protective work for supporting railroads, roads and the like when excavating a large number of underground structures in the lower ground such as railroads and roads in the same manner as the pipe roof construction method.

  In order to dig a large number of underground structures in the lower ground such as railways and roads in the transverse direction, it is necessary to have a protective work for supporting the upper traffic. It is possible to construct a roof, etc., but it is possible to work safely, reliably and inexpensively because it will be carried out at the same time as excavation of the underground structure without constructing the protective work of the underground structure to be excavated underground. In addition, the following construction methods (R & C method, SFT method) are known as methods that allow shallow covering.

  This is a construction method in which an underground structure is constructed without digging under a railroad, a road, or a river. As shown in FIG. 12, a box-shaped roof 6 serving as a protective member and a box culvert serving as a main body structure are provided. Body) This is a construction method for constructing underground structures without excavation by replacing 9.

  The box-shaped roof method is a method of installing the box-shaped roof 6 as the protective member.

  First, a retaining wall 2 is constructed on the side of the upper traffic 1 such as a railroad, a starting shaft 3 and a reaching shaft 4 are constructed, and a steel box roof 6 having a small cross section is connected to the outer edge (top and side surfaces) of the box section. ) Is placed over the entire length of the cross section to match

  Next, a box is installed at the end of the box-shaped roof 6, and the box-shaped roof 6 and the box 9 are pressed alternately. In place.

  The construction method of the underground structure using the concrete box 9 is selected from the propulsion method and the towing method according to the topographical conditions and the construction scale. The example shown in FIG. 12 is a propulsion system. A reaction force wall 8 and a box 9 are set in the starting shaft 3, and a propulsion jack 10 is provided between the reaction force wall 8 and the box 9. A blade opening 11 is provided at the tip of the body 9 and a jack storage tube 12 containing a small jack is interposed between the tip of the box 9 and the box roof 6.

  In the figure, 13 is a support material for the box-shaped roof 6, 14 is a fixing member for the friction cut plate 7, which are provided on the start shaft 3 side, while a removal platform 15 is provided on the arrival shaft 4 side.

  The small jack is extended to the jack storage tube 12, and the box-shaped roof 6 is pushed forward one by one while leaving the friction cut plate 7 using the box 9 as a reaction force. Next, the propulsion jack 10 is extended to dig up the box 9. In FIG. 12, 16 is a strut interposed between the propulsion jack 10 and the box 9, 26 is a spacer, and 27 is a starting base.

  In this way, the box-shaped roof 6 that has come out to the reaching shaft 4 is sequentially removed while alternately repeating the advance of the box-shaped roof 6 and the advance of the box 9.

  And if the front-end | tip of the box 9 reaches the arrival shaft 4, the blade edge 11 grade | etc., Will be removed, a backfill grout will be performed suitably, and construction will be completed.

  The box 9 may be made of precast concrete that is sequentially suspended and connected in the start shaft 3, or concrete is cast in the start shaft 3 to increase the required length. May be.

  In the construction method of an underground structure in which a concrete roof (box) is promoted and replaced with a box roof after the box roof is constructed on the track as described above, the box roof as shown in FIG. There is a tendency to bend in the vertical direction during propulsion and during the rest from propulsion to the box propulsion, causing the track and road surface to move up and down, and this flexing part interferes with the excavation of underground structures. Also, construction becomes difficult.

The following patent documents are proposed as a roof cylinder subsidence prevention device and a subsidence prevention method in a construction method of an underground structure that can prevent the roof cylinder from bending downward and improve workability. is there.
Japanese Patent No. 3702265

  As shown in FIG. 14, a box-shaped roof 6 having a friction cut plate 7 disposed on the top is press-fitted into the ground from the start shaft 3 and arranged in parallel, and a box 9 is placed at the rear of the box roof 6 remaining in the start shaft 3. In the construction method of an underground structure that is disposed and allows the box 9 to be excavated while leaving the friction cut plate 7 in the ground, a portion of the box-shaped roof 6 that is bent downward in the longitudinal direction inside the box-shaped roof 6. The ropes 17a and 17b for pulling up are penetrated.

  By pulling the rope penetrated in the longitudinal direction inside the box-shaped roof 6 in the horizontal direction, the vertical vertical force acting on the string is transmitted to the box-shaped roof 6, and the box-shaped roof The deflection portion of 6 is pulled up, and the deflection is eliminated.

  As means for preventing the deflection of the box-shaped roof 6, bolts and nuts 19 are mainly added or a retrofit plate on the tension side (the lower side of the roof) is used, but a sufficient effect can be obtained. I could not do it.

  Further, in the prevention of the settlement of the roof cylinder according to Patent Document 1, the flexible portion is pulled up by the rope, and similarly, a sufficient effect cannot be obtained.

  The object of the present invention is to eliminate the disadvantages of the conventional example, and to reduce the bending of the box-shaped roof easily and reliably, and to obtain a guide for propelling the box-shaped roof. It is intended to provide a box roof deflection reduction method for a box roof construction method that can improve workability because it can prevent changes and prevent rebound of natural ground, so that the opening of the box roof can be prevented. .

  In order to achieve the above object, the present invention according to claim 1 is a protective work for supporting the upper traffic in order to excavate a concrete box as an underground structure in a lower ground such as a railway or a road. In the box-type roof construction method in which the start and end shafts are constructed, and the steel box roof with a small cross section is arranged in the entire length of the transverse section so as to match the outer edge of the box cross section, The gist is that a guide plate made of a steel plate having a plurality of widths is arranged in advance in the entire length of the transverse section, and the box-shaped roof is dug on the guide plate.

According to the present invention as defined in claim 1,
(1) The guide plate is pulled in, and this is used as guide steel to allow the box-shaped roof to dig up on the guide plate. Therefore, the guide plate can reduce the box-shaped roof from being bent downward.
(2) It also prevents the opening of the box-shaped roof.
(3) Furthermore, rebound of the natural ground can be suppressed by the guide plate, and rebound does not occur, so the amount of settlement can be reduced.
(4) A friction reduction effect is obtained by the guide by the guide plate, and the construction of the box roof is accelerated.
(5) By causing the guide plate to precede, dilatancy (soil is shearing force, the arrangement state of soil particles is changed and volume change is caused) is suppressed.
(6) Since the guide plate is extruded together with the box-shaped roof, it can be diverted.

  Due to the above-described merits, it is possible to prevent deflection during propulsion and remaining, and to reduce the influence of the vertical displacement of the track.

  In addition, since propulsion on the steel plate is expected, a reduction in the propulsive force can be expected, leading to a reduction in the number of jacks, which leads to an economic advantage.

  In the present invention according to claim 2, the guide plate is disposed in advance by installing a wire saw, installing a PC steel wire for drawing in the guide plate, excavating ground with the wire saw, and drawing in the guide plate with the PC steel wire. The main point is to do this.

  According to the second aspect of the present invention, the guide plate can be easily placed because the guide plate is disposed by excavating the ground with a wire saw and retracting the guide plate with a PC steel wire.

  The gist of the present invention described in claim 3 is that the guide plate has an acute angle at the tip.

  According to the third aspect of the present invention, the guide plate can be easily pulled in by making the front end an acute angle.

  As described above, the box-shaped roof cylinder of the present invention can easily and reliably bend the box-shaped roof cylinder in a simple operation by preventing rebound of natural ground. It is possible to prevent and improve the workability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 are side views showing the first to third steps of the box roof deflection reducing method of the box roof construction method, FIGS. 4 to 6 are the same plan views, and FIGS. 7 to 9 are the front views. is there.

  The present invention constructs a start shaft 3 and a reach shaft 4 as a protective work for supporting the upper traffic in order to excavate the concrete box 9 as an underground structure in the lower ground such as a railway or a road. The premise is a box roof construction method in which the steel box roof 6 having a small cross section is arranged in a row in the entire length of the transverse section so as to match the outer edge of the box cross section.

  First, the box-shaped roof 6 will be described. As shown in FIG. 11, a joint flange 6c is formed at the end, and the joint flange 6c is a plate body in which a bolt insertion hole is formed, and these are overlapped with each other. The bolt can be fastened with.

  The standard cross-sectional shape of the box-shaped roof 6 is 1,000 × 1,000 (mm) and the length is 3,000 (mm), or the cross-sectional shape is 800 × 800 (mm) and the length is 6,000 (mm) ), There are cases where there are joints 6a and 6b, which are bowl-shaped components on the side surface, and there are no joints.

  Further, the box-shaped roof 6 has a box corner 6d with an open end corner that is open outward, and this is a bolt / nut fastening portion. In addition, although illustration is abbreviate | omitted, the blade edge | tip is provided in the front-end | tip of the box-shaped roof 6. FIG.

  In the present invention, guide plates 23 made of steel plates having a width corresponding to a plurality of (for example, two or three) box roofs 6 arranged in a row are arranged in advance in the entire transverse section.

  As shown in FIG. 10, the guide plate 23 may have an acute angle 23a at the tip, and a lubricant may be applied to the upper surface or the peripheral surface.

  As a first step, as shown in FIGS. 1, 4, and 7, first, a wire saw and a guide plate pull-in PC are inserted so that the start shaft 3 and the arrival shaft 4 formed by constructing the retaining wall 2 are inserted. A steel wire hole 22 is formed.

  The wire saw 20 is installed in the reaching shaft 4, and the wire 21 is drawn through the wire saw and the guide plate pull-in hole 22 for the PC steel wire, and arranged so as to reach the start shaft 3.

  Further, the guide plate drawing PC steel wire 24 is installed through the guide plate drawing PC steel wire hole 22. A traction jack 25 of PC steel wire 24 is installed in the reaching shaft 4.

  The guide plate 23 is placed on the start shaft 3 (illustration of the mounting table is omitted), and the PC steel wire 24 and the guide plate 23 are fixed.

  A ground drilling is performed by the wire saw 20, and a hole that can be propelled by the guide plate 23 is drilled ahead, and then the guide plate 23 is pulled by towing with the towing jack 25.

  The guide plate 23 welds steel plates adjacent to each other at the start shaft 3 to form a large steel plate body.

  As a second step, as shown in FIGS. 2, 5, and 8, the guide plate 23 and the retaining wall 2 are fixed at the time of construction of the box-shaped roof. suppress.

  The box-shaped roof 6 is propelled on the guide plate 23. The digging of the box roof 6 is as described above.

  As a third step, as shown in FIGS. 3, 6, and 9, the blade edge 11 and the box 9 are installed, the box-shaped roof 6 and the guide plate 23 are driven, and the box 9 is dug.

  The small jack of the jack storage tube 12 is extended to push the box roof 6 one by one while leaving the friction cut plate 7 using the box 9 as a reaction force. Next, the propulsion jack (not shown) is extended to dig up the box 9.

  A removal stand 15 is provided on the reach shaft 4 side, and the box-shaped roof 6 and the guide plate 23 are removed.

  In addition to the above-described embodiment, the present invention is a case where a concrete box is propelled after press-fitting a box-shaped roof as disclosed in Japanese Patent No. 4134089. Because it extrudes, it does not require additional work to excavate the face, reducing costs and shortening the work period.In addition, safety can be improved by eliminating the work of excavating the face with danger. By distributing the reaction force resistance for propelling, it can be applied to construction methods for underground structures that do not require large-scale facilities.

  This construction method (Simple and Face-Less Method of Construction of Tunnel) is named SFT construction method as an abbreviation of “Simple construction without tunnels”, and the first step is upper traffic such as railway (not shown) ) A retaining wall is placed next to), a starting pit and a reaching mine are built, a propulsion unit is installed in the starting pit, and a box-shaped roof that is a roof cylinder is pressed into the reaching pit. Let A friction cut plate is attached to the upper surface of the box-shaped roof in the same manner as before, and is extruded together with the box-shaped roof.

  The box-shaped roof is arranged in a quadrangular shape so as to correspond to the outer shape of the concrete box to be propelled, and a earth retaining member is disposed on the face portion surrounded by the box-shaped roof.

  Next, as the second step, the concrete box is installed on the starting platform of the start pit, a tow jack is attached to the rear of the concrete box, and the tip of the concrete box is joined to the rear end of the box-shaped roof that was previously pushed out. Alternatively, the concrete box is pulled from the start pit toward the arrival pit as a third step.

  At the same time as pulling the concrete box, the box roof is pushed out, and the face is not excavated. When the box roof is pushed out, the earth and sand surrounded by the box roof is pushed out at the same time.

  In this way, if the fourth step box roof and the earth and sand simultaneously pushed out by being surrounded by the box roof reach the access shaft, the box roof is removed from the access shaft, and at the same time, the soil is excavated and discharged. Soil.

  Then, the concrete box is pulled until the tip of the concrete box reaches the arrival hole 4, and the full length of the concrete box is completed.

  The above explained the case of pulling the concrete box, but set the reaction wall in the starting pit, an underground structure with the concrete box, and provided a push jack between the reaction wall and the concrete box, You may make it extend a main pushing jack and dig a concrete box.

It is a side view which shows the 1st process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a side view which shows the 2nd process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a side view which shows the 3rd process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a plane which shows the 1st process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a top view which shows the 2nd process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a top view which shows the 3rd process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a front view which shows the 1st process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a front view which shows the 2nd process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a front view which shows the 3rd process of the box-shaped roof bending reduction method of the box-shaped roof construction method of this invention. It is a partial side view of a guide plate. It is a perspective view of a box-shaped roof. It is a perspective view of the construction method (R & C method) of an underground structure. It is explanatory drawing which shows the bending of a box-shaped roof. It is a side view which shows a prior art example.

DESCRIPTION OF SYMBOLS 1 ... Upper traffic 2 ... Earth retaining wall 3 ... Starting shaft 4 ... Reaching shaft 5 ... Press-fit machine 6 ... Box-type roof 6a ... Joint 6c ... Joint flange 6d ... Box opening 7 ... Friction cut plate 8 ... Reaction force wall 9 ... Box Body 10 ... Propulsion jack 11 ... Blade 12 ... Jack storage tube 13 ... Support material 14 ... Fixing member 15 ... Removal base 16 ... Struts 17a, 17b ... Rope 19 ... Bolt, nut 20 ... Wire saw 21 ... Wire 22 ... Wire Saw and guide plate lead-in hole 23 for PC steel wire ... Guide plate 23a ... Sharp angle 24 ... PC steel wire 25 ... Towing jack 26 ... Spacer 27 ... Starting stand

Claims (3)

In order to excavate the concrete box in the transverse direction as an underground structure in the lower ground of railways, roads, etc., as a protective work to support the upper traffic, a starting shaft and a reaching shaft are constructed and steel with a small cross section In the box-shaped roof construction method in which the box-shaped roof is arranged in a row across the entire length of the transverse section so as to match the outer edge of the box section,
A guide plate made of a steel plate having a width corresponding to a plurality of box-shaped roofs arranged in a row is arranged in advance in the entire length of the transverse section,
A method for reducing the deflection of a box roof by the box roof construction method, wherein the box roof is formed by digging the guide plate.   2. The box shape according to claim 1, wherein the guide plate is disposed in advance by installing a wire saw, installing a PC steel wire for drawing in the guide plate, excavating the ground with the wire saw, and drawing the guide plate with the PC steel wire. Box roof deflection reduction method for roof construction method.   The method for reducing the deflection of a box-shaped roof according to claim 1 or 2, wherein the guide plate has a sharp tip.

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