JP5966632B2 - Reverse strut fixing structure and reverse strut fixing method - Google Patents

Description

  The present invention relates to a reverse strut fixing structure and a reverse strut fixing method, and specifically relates to a technique for fixing a reverse strut with good accuracy and workability.

  The reverse struts (construction pillars) in the reverse strike method are erected in the casing and earth retaining wall provided on the construction ground, with the bottom end embedded in the concrete of cast-in-place piles, while taking verticality into consideration. Is done. In order to fix the lower end of the reverse strut to an appropriate position, conventionally, an underwater jack or a panda jack is arranged between the reverse strut and the casing or retaining wall, and the stroke of the jack is extended to increase the above-mentioned casing, etc. The reaction force was taken on the wall surface of the arm, and the position adjustment and fixing of the lower end of the striking strut was attempted.

  For example, after installing a steel bar in the hole, install a lower correction jack in the standpipe, and separate the lower frame and upper After installing the lower frame in the frame, placing the concrete board in the hole, installing the upper frame on the lower frame, and building the structural pillar while adjusting it using the means for correcting the upper frame and the lower correction jack. A built-in construction method (Patent Document 1) of a structural pillar characterized by the above has been proposed.

JP-A-7-238546

  The above-mentioned cast-in-place piles have different cross-sectional shapes depending on the construction, and in recent years, have a tendency to increase in cross section. With such a tendency, the area in the casing and the retaining wall is also enlarged, and as a result, the separation distance between the counter strut and the casing and the retaining wall becomes longer. On the other hand, the strokes of jacks conventionally employed are limited and cannot be accommodated to the above-mentioned separation distance as they are, so it is necessary to compensate for the stroke shortage by installing a bracket on the side of the striking strut. However, in a limited construction area, performing the erection operation while handling the striking strut having a bracket projecting sideways has a problem that the construction efficiency tends to be lowered. In addition, there is a problem that the strength of the bracket that protrudes to the side of the striking strut and has a corresponding length is insufficient, and the accuracy of the fixed position of the striking strut tends to be lowered. Furthermore, the brackets and jacks cross the casing and the retaining wall, and there is a concern that the arrangement of various construction equipment such as a tremy pipe at the time of placing concrete may be hindered.

  Therefore, an object of the present invention is to provide a technique for fixing the back strut with good accuracy and workability.

  The reverse strut fixing structure that solves the above-mentioned problem is that the upper end is locked to the ground surface or the upper portion of the built-up area between the wall of the built-up area and the reverse strut in the built-up area of the reverse strut. A member having a predetermined width extending downward in parallel with the counter strut is disposed, and a jack is installed between the lower end of the member and the wall of the counter strut and the built-in area. It is characterized by.

  According to this invention, it corresponds to the large cross-section of the pile, etc., even if the separation distance between the backlash strut and the wall surface of the casing or the like is long, it does not depend on the stroke limit of the jack and the backlash strut Can be secured securely. Further, unlike the prior art, there is no need to install a bracket on the back strut, so that the back strut can be efficiently handled and built in the construction area. In addition, the strength of the above-described member is sufficient, and the accuracy of the fixed position of the backlash strut can be good. Furthermore, since the above-mentioned members can be formed from existing steel pipes, earth retaining materials, etc., they can be manufactured at low cost and with little effort, which leads to a reduction in overall construction costs. Furthermore, the above-mentioned members are steel pipes and frames, and it is possible to arrange various construction equipment such as tremy pipes at the time of placing concrete in the interior thereof. . Therefore, according to the present invention, it is possible to fix the back strut with good accuracy and workability.

  In the above-described striking strut fixing structure, a plurality of the members are arranged between the wall surface of the erection region and the striking strut, and between the bottom end of each member, the bottom end of one member and the above A jack may be installed between the counter strut and between the lower end of the other member and the wall surface of the building area. According to this, even if the separation distance between the wall surface of the erection area and the striking strut is very large, if a plurality of the above-mentioned members are arranged at an interval based on the stroke limit of the jack, it is flexible. It becomes possible to cope with.

  Moreover, in the above-described reverse strut support structure, the member may be made of a steel pipe. According to this, the reaction force transmitted from the jack can be surely transmitted to the back struts by the high strength of the steel pipe, and thus the back struts can be firmly fixed. Moreover, since there is no protrusion etc. in the inside of a steel pipe and it is smooth, it becomes easy to arrange | position various construction apparatuses, such as a tremy pipe.

  Further, in the above-described reverse strut fixing structure, the member may be formed of a frame body in which a shape steel material or a mountain retaining material is combined. According to this, when manufacturing the above-mentioned members, it is possible to manufacture any shape and size with any combination of low-cost structural steel and retaining materials, so it can flexibly handle the size and shape of the above-mentioned building area As a result, such a member can be used to securely fix the striking strut.

  Further, according to the reverse strut fixing method of the present invention, the upper end is locked to the ground surface or the upper portion of the built-up area between the wall of the built-up area and the reverse strut in the built-up area of the reverse strut. And, a step of arranging a member of a predetermined width extending downward in parallel with the reverse struts, and installing a jack between each of the lower end of the member and the reverse struts and the wall surface of the building area, And a step of taking a reaction force on the wall surface of the erected area by the jack and fixing the lower end of the member.

  According to the present invention, it is possible to fix the striking strut with good accuracy and workability.

It is a top view which shows the structural example 1 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 1 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 2 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 2 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 3 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 3 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 4 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 4 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 5 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 5 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 6 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 6 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 7 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 7 of the reverse strut support structure of this embodiment. It is a top view which shows the structural example 8 of the reverse strut support structure of this embodiment. It is a sectional side view which shows the structural example 8 of the reverse strut support structure of this embodiment. It is a figure which shows the 1st process in the construction procedure of the reverse strut support method of this embodiment. It is a figure which shows the 2nd process in the construction procedure of the reverse strut support method of this embodiment. It is a figure which shows the 3rd process in the construction procedure of the reverse strut support method of this embodiment. It is a figure which shows the 4th process in the construction procedure of the reverse strut support method of this embodiment. It is a figure which shows the 5th process in the construction procedure of the reverse strut support method of this embodiment. It is a figure which shows the 6th process in the construction procedure of the reverse strut support method of this embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a top view showing a structural example 1 of the reverse strut fixing structure 100 of the present embodiment, and FIG. 2 is a side sectional view of the reverse strut fixing structure 100. In the construction site where the reverse driving method is adopted, building piles are constructed from the ground surface to the ground. In the example shown in FIGS. 1 and 2 (hereinafter, the same applies to FIGS. 3 to 16), the erected area 4 is constructed by excavating from the ground surface 5 to the predetermined depth of the ground 1 while filling with the stabilizing liquid 2. A cast-in-place pile (not shown) that supports the lower end portion 8 of the reverse strut 6 is placed in the ground below the recessed region 4.

  Under such circumstances, the striking strut fixing structure 100 of the present embodiment has a striking strut 6 and a striking strut 6 between the wall 3 of the construction region 4 and the striking strut 6 in the construction area 4 of the striking strut 6. A reaction force column 10 is provided in parallel. The reaction force column 10 is formed of a steel pipe having a circular or rectangular cross section, and the upper end member 11 of the upper surface fixing member 65 of the ground surface 5 or the erected region 4 is locked by a fixing jig 60. . The striking strut fixing structure 100 includes a jack 30 that can be expanded and contracted in the horizontal direction and is installed between the lower end portion 12 of the reaction force column 10 and the striking strut 6 and the wall surface 3 of the erection region 4. Yes.

  On the other hand, the striking strut 6 fixed by the striking strut fixing structure 100 of the present embodiment locks the upper end 7 of the upper fixing member 65 of the ground surface 5 or the erection region 4 with the fixing jig 60. In consideration of the verticality, the lower end 8 is embedded in the concrete 50 near the pile head of the cast-in-place pile. In fixing the lower end 8 of the reverse strut 6 to an appropriate position, in the reverse strut fixing structure 100 of the present embodiment, the reaction force column is higher than the jack 30 having a fulcrum on the wall surface 3 of the above-described built-up region 4. The ground reaction force 10 is transmitted to the jack 10, and the reaction force column 10 receiving this transmits the ground reaction force to the jack 30 between the striking strut 6 and the counter striking column 6 facing itself, and finally the jack. The ground reaction force is transmitted to the back strut 6 through 30. The striking strut 6 receives the ground reaction force from the wall surface 3 at the position opposite to the wall surface 3 with the same structure as described above, so the ground reaction force is received from the jacks 30 on both side surfaces and securely fixed. .

  In addition, the reaction force column 10 in this embodiment has a width 15 at the position where the jack 30 is attached in the vicinity of the lower end portion 12, and is a distance 16 between the counter strut 6 and the wall surface 3 of the erection region 4. In addition, a jack that is longer than the distance excluding the total stroke limit length of each jack 30 attached to both side surfaces of the reaction force column 10 is employed. That is, even when each jack 30 is operated and the stroke is extended to the limit, it is considered that the ground reaction force can be reliably transmitted to the counter striking column 6 via the reaction force column 10. The method for setting the width 15 of the reaction force column 10 at the mounting position of the jack 30 is the same for the reaction force member 20 described later.

  Moreover, the above-mentioned reaction force column 10 has a predetermined rigidity as a whole, and at a mounting position of the jack 30 installed between the counter strut 6 and the wall surface 3 of the erection region 4, a predetermined rigidity is provided. As long as the structure has a width 15, it does not have to have the same width (cross-sectional diameter) over the entire length. Therefore, it is possible to adopt a structure constituted by a small-diameter member such as a steel bar other than the position where the jack 30 is attached.

  Further, the reaction force column 10 in the above-described reverse strut supporting structure 100 is made of a steel pipe, and there is no projection or the like in its inner space and is smooth. Therefore, it is easy to arrange various construction equipment such as tremy tubes.

  Next, an example in which the reverse strut supporting structure 100 is configured with the reaction force member 20 instead of the reaction force column 10 described above will be described. FIG. 3 is a top view showing a structural example 2 of the reverse strut supporting structure 100 according to this embodiment, and FIG. 4 is a side sectional view of the reverse strut fixing structure 100.

  In this case, the reaction force member 20 is a frame formed by combining, as a vertical member 24 and a horizontal member 25, a shape steel material or a mountain retaining material appropriately selected according to the size and shape of the erected region 4 and the back strut 6. It is. The reaction force member 20 has an inner space 23 extending from the upper end portion 21 to the lower end portion 22, and various construction devices can be arranged in the inner space 23, similar to the reaction force column 10 described above. .

  Moreover, the steel material (especially the mountain retaining material) constituting the reaction force member 20 is a general-purpose product that is easy to introduce and operate and is low-cost, and is pre-processed such as bolt holes that facilitate assembly operations such as connection. And is very easy to handle. Therefore, the reaction force member 20 using such a steel material flexibly corresponds to the size of the separation distance 16 between the wall surface 3 of the erection region 4 and the counter strut 6 and the shape of the erection region 4. In addition, it can be configured at low cost.

  Next, the form in which the plurality of reaction force columns 10 are continuously arranged via the jack 30 in the built-in region 4 will be described. FIG. 5 is a top view showing a structural example 3 of the reverse strut supporting structure 100 according to this embodiment, and FIG. 6 is a side sectional view of the reverse strut fixing structure 100.

  Here, in the built-in area 4, the ground reaction force is received only on the jack 30 on one side surface of the reverse strut 6 without using the reaction force column 10 or the like. On the other side, the case where ground reaction force is transmitted through a plurality of reaction force columns 10 (and jacks 30) arranged continuously is illustrated.

  If such a form is adopted, even if the separation distance 16 between the wall surface 3 of the erection region 4 and the counter strut 6 is very large, the above-described anti-reflection is performed at an interval based on the stroke limit of the jack 30. A plurality of force columns 10 can be arranged to respond flexibly and reliably, and the counter strut 6 can be fixed with the ground reaction force transmitted by them. The number of the reaction force columns 10 is the sum of the width 15 in the vicinity of the lower end 12 of the reaction force column 10 and the stroke limit length of the jack 30. The distance between the region 4 and the wall surface 3) can be obtained as a value obtained by dividing.

  Although an example in which a plurality of reaction force columns 10 are arranged is shown here, it is needless to say that a plurality of reaction force members 20 may be arranged in the same manner.

  Instead of such a form in which the plurality of reaction force columns 10 or the reaction force members 20 are continuously arranged, a form in which the width 26 of the reaction force member 20 is expanded in accordance with the separation distance 16 may be employed. FIG. 7 is a top view showing a structural example 4 of the reverse strut fixing structure 100 according to the present embodiment, and FIG. 8 is a side sectional view of the reverse strut fixing structure 100.

  In this case, the sum of the stroke limit lengths of the two jacks 30 attached to both sides of the reaction force member 20 is subtracted from the above-described separation distance 16 (distance between the counter strut 6 and the wall surface 3 of the erection region 4). The obtained value can be obtained as the width 26 of the reaction force member 20. The reaction member 20 can be constructed by adopting a steel material of an appropriate length as the cross member 25 and assembling so as to have the width 26 thus obtained.

  On the other hand, in addition to the case where the separation distance 16 is large, the reverse strut support structure 100 of the present embodiment is also applied when the depth of the built-in region 4 is deep, that is, when the reverse strut 6 is long. it can. FIG. 9 is a top view showing a structural example 5 of the inverted strut fixing structure 100 of the present embodiment, and FIG. 10 is a side sectional view of the inverted strut fixing structure 100. In this case, the reaction force column 10 is formed of a steel pipe corresponding to the length of the long striking strut 6, and in the same manner as in FIGS. The jack 30 is disposed between the lower end 12 of the reaction force column 10 and between the wall surface 3 of the erection region 4 and the lower end 12 of the reaction column 10 to fix the back strut 6. If you do.

  However, since the steel pipe is not cheap, when the reaction force column 10 having the above-described form is adopted, there may be a case where the construction cost is restricted. In that case, the reaction force member 20 may be adopted instead of the reaction force column 10. FIG. 11 is a top view showing a structural example 6 of the inverted strut fixing structure 100 according to the present embodiment, and FIG. 12 is a side sectional view of the inverted strut fixing structure 100.

  In this case, in accordance with the length of the long striking strut 6, steel members are combined to form the vertical member 24, and the cross member 25 is combined with this to form the reaction member 20. 3 and 4, between the vicinity of the lower end portion 8 of the counter strut 6 and the lower end portion 22 of the reaction force member 20 facing this, and against the wall surface 3 of the building region 4. What is necessary is just to arrange | position the jack 30 between each with the lower end part 22 of the force member 20, and to fix the striking strut 6.

  On the other hand, when the reverse strut fixing structure 100 is configured by adopting the long reaction force member 20 or the reaction force column 10 as described above, due to a slight inclination generated when building from the ground surface 5, When the vicinity of the bottom is reached, the reaction force member 20 or the front end portion of the reaction force column 10 may be greatly inclined. Such inclination is illustrated in FIGS. 13 and 14. FIG. The broken line in each figure has shown the position when the reaction force members 20 etc. are built in the perpendicular direction. When such inclination occurs, for example, the lower end portion 22 of the reaction force member 20 may exceed the stroke limit by the jack 30a on one side surface, and may not be able to transmit the ground reaction force.

  Therefore, it is preferable to employ a configuration in which an inclinometer 70 such as a water pipe is installed in the reaction force member 20 or the reaction force column 10. FIG. 15 is a top view showing a structural example 8 of the reverse strut supporting structure 100 according to this embodiment, and FIG. 16 is a side sectional view of the reverse strut fixing structure 100. In this case, the verticality of the reaction force member 20 in the built-in region 4 is confirmed by the inclinometer 70, the jack 30 is operated according to the amount of inclination indicated by the inclinometer 70, and the verticality of the reaction force member 20 is determined. Will be secured.

  For example, when the inclinometer 70 shows a predetermined amount of inclination in the direction 71 in the reaction member 20, the stroke of the jack 30d is activated while the stroke of the jack 30c is extended by a predetermined amount accordingly. The verticality of the reaction force member 20 is ensured by operating it so that it shrinks by a predetermined amount. Of course, when the inclinometer 70 indicates a predetermined amount of inclination in the direction 72 in the reaction member 20, the stroke of the jack 30c is increased while the stroke of the jack 30c is increased accordingly. The verticality of the reaction force member 20 is ensured by operating so as to reduce only a fixed amount.

  If the reverse strut fixing structure 100 of such a form is adopted, the above-mentioned reaction force member 20 and the reaction force column 10 can be used even in a situation where the reverse strut 6 is fixed to the deeply built-up region 4. It becomes possible to install it while ensuring its verticality. Further, when the jack 30 and the like are operated, if it is checked that the indicated value of the inclinometer 70 varies correspondingly, the jack 30 and the like obtain the ground reaction force from the wall surface 3 of the erection area 4, and There is also an effect that it can be confirmed that the ground reaction force is reliably transmitted to the reaction force member 20 and the like.

  Next, the construction method of the back strut fixing structure 100, that is, the construction procedure of the back strut fixing method will be described. FIGS. 17-22 is a figure which respectively shows the 1st process-the 6th process in the construction procedure of the reverse strut fixing method of this embodiment. Here, the case where the counter strut fixing structure 100 is constituted by the reaction force column 10 and the jack 30 is illustrated.

  In this case, excavation is executed while filling the stabilizing liquid 2 from the ground surface 5 to a predetermined depth of the ground 1 in the ground 1 to be subjected to the reverse driving method. By this process, the erected area 4 is formed on the ground 1 (FIG. 17). A cast-in-place pile (not shown) that supports the lower end portion 8 of the reverse strut 6 is placed in the ground below the erected region 4. Further, an upper fixing member 65 fixed to the ground surface 5 is installed at the upper part of the built-in area 4. The upper fixing member 65 is a member serving as a fulcrum for fixing the reaction force column 10 and the upper end of the counter strut 6 and is made of steel, concrete, or the like.

  In the situation where the erection region 4 is configured, the reaction force column 10 is gradually suspended from the ground surface 5 at a predetermined distance from the wall surface 3 of the erection region 4 (FIG. 18), and arranged at a predetermined depth. . Further, the upper end portion 11 of the reaction force column 10 suspended to a predetermined depth is fixed by the fixing jig 60 by the upper fixing member 65 described above. Note that a jack 30 with a reduced stroke is attached to the side surface of the front end portion 12 of the reaction force column 10.

  Once the reaction force column 10 is placed in the erection region 4, the counter strut 6 is suspended from the ground surface 5 between the reaction force columns 10 (FIG. 19) and placed at a predetermined depth. In addition, the upper end portion 7 of the striking strut 6 suspended to a predetermined depth is fixed by the fixing jig 60 by the upper fixing member 65 described above.

  When the reaction force column 10 and the counter striking strut 6 are arranged in parallel in the erection region 4, the jack 30 provided at the distal end portion 12 of the reaction force column 10 is operated to extend its stroke. Among the jacks 30, those that contact the wall surface 3 of the erected area 4 contact the wall surface 3 to obtain the ground reaction force, and transmit the ground reaction force to the reaction force column 10 through the other fulcrum. To do. On the other hand, among the jacks 30, those in contact with the reverse striking strut 6 abut the fulcrum against the reverse striking strut 6. In this case, the reaction force column 10 transmits the ground reaction force transmitted from the jack 30 that has obtained the ground reaction force to the striking strut 6 via the jack 30 provided on the other side surface. The transmission reaction of the ground reaction force is executed by the reaction force columns 10 and the jacks 30 on both sides of the counter strut 6 and the verticality of the counter strut 6 is confirmed by the inclinometer 70 while its lower end 8 Is fixed at a predetermined position near the pile head of the cast-in-place pile.

  As described above, when the backlash strut 6 is fixed by the backlash strut fixing structure 100, the tremy tube 80 is inserted from the ground surface 5 into the inner space 13 of the reaction force column 10, and the bottom of the erection region 4 is inserted. A predetermined amount of concrete 50 is placed (FIG. 20). By this concrete placement, the cast-in-place pile located below and the lower end portion 8 of the counter-strut 6 are integrated. When the concrete 50 placed in the erection area 4 is solidified through sufficient curing (FIG. 21), the stroke of the jack 30 is shortened in the above-described reaction force column 10 arranged around the counter strut 6. After the operation is performed, the upper end portion 11 is also fixed by the upper fixing member 65, and the reaction force column 10 is lifted to the ground surface 5 and removed (FIG. 22). In this way, the reverse strut 6 is securely fixed with good verticality at the pile head of the cast-in-place pile in the erected region 4.

  As described above, according to the present embodiment, it is possible to fix the back strut with good accuracy and workability. Further, although the embodiment of the present invention has been specifically described based on the embodiment, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Ground 2 Stabilizing liquid 3 Wall surface 4 Built-in area 5 Ground surface 6 Reverse strut 7 Upper end part 8 Lower end part 10 Reaction force column (member)
11 Upper end portion 12 Lower end portion 13 Inner air 20 Reaction member (member)
21 Upper end portion 22 Lower end portion 23 Inner air 24 Vertical member 25 Cross member 30 Jack 40 Inclinometer 50 Concrete 60 Fixing jig 65 Upper fixing member 70 Inclinometer 80 Tremy tube 100 Reverse strut fixing structure

Claims (5)

In the built-up area of the back strut, between the wall of the built area and the back strut,
An upper end is locked to the ground surface or the upper part of the built-up area, a member having a predetermined width extending in parallel with the reverse strut is disposed, the lower end of the member, the reverse strut and the built-up area Reverse strut fixing structure, characterized in that a jack is installed between each and the wall surface.   A plurality of the members are arranged between the wall surface of the building area and the back struts, between the lower ends of each member, between the lower end of one member and the back struts, and the other member The striking strut fixing structure according to claim 1, wherein a jack is installed between each of a lower end portion of the base plate and a wall surface of the building area.   3. The reverse strut fixing structure according to claim 1, wherein the member is made of a steel pipe.   The reverse strut fixing structure according to claim 1 or 2, wherein the member is a frame body in which a shape steel material or a mountain retaining material is combined. In the built-up area of the back strut, between the wall of the built area and the back strut,
A step of locking a top end on the ground surface or an upper part of the erection region, and arranging a member having a predetermined width extending downward in parallel with the reverse strut;
A jack is installed between the lower end portion of the member and the striking strut and the wall surface of the built-in area, and the reaction force is taken on the wall surface of the built-up area by the jack so that the lower end portion of the member is Fixing, and
A reverse strut fixing method characterized by including:

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