JP6574108B2 - Method for reinforcing concrete structures - Google Patents

Description

  The present invention relates to a method for reinforcing a concrete structure embedded in the ground.

  Concrete structures such as box culverts that are buried in the ground and construct underground railway tunnels, automobile underground tunnels, and other underground structures are known. As a method for reinforcing such a concrete structure, a method has been proposed in which a hole is formed in the wall of the concrete structure, a reinforcing member is inserted into the hole, and a filler is filled or an injection material is injected. (Patent Document 1).

Japanese Patent Laying-Open No. 2015-21299

  The reinforcing method described in Patent Document 1 does not form a hole from the inner surface of the wall in the wall of the concrete structure, but forms a hole from the upper end surface of the wall. Therefore, there is no need to restrict the passage of trains and automobiles in underground tunnels constructed with concrete structures during construction, and there are few restrictions on construction time and the like.

  Moreover, in the reinforcement method described in Patent Document 1, a hole extending in the vertical direction is formed in the wall of the concrete structure, and the reinforcing member is inserted into the hole over substantially the entire length thereof. Therefore, the extending direction of the reinforcing member and the shear fracture line surely intersect, and a high reinforcing effect can be obtained.

  On the other hand, in Patent Document 1, concrete, mortar, and adhesive are listed as fillers filled in the holes into which the reinforcing members are inserted, but the filler filled in the holes is always one type, A plurality of types of fillers are not filled in the same hole.

  Here, in a concrete structure, the reinforcement strength and the reinforcement performance which are calculated | required by the site | part may differ. Specifically, in order to improve the yield strength of the entire concrete structure in a well-balanced manner, some parts are reinforced with an emphasis on compressive strength, and other parts are reinforced with an emphasis on tensile strength. It is desirable to apply. However, in the reinforcing method described in Patent Document 1 in which a hole provided in the wall of the concrete structure is filled with one type of filler, reinforcement that focuses on compressive strength and reinforcement that focuses on tensile strength are used separately. I can't.

  An object of the present invention is to provide a method capable of applying reinforcement suitable for an arbitrary part of a concrete structure.

  One method for reinforcing a concrete structure according to the present invention is a method for reinforcing a concrete structure that includes a bottom portion and a wall portion that stands vertically from the bottom portion and is buried in the ground. This reinforcing method includes a perforation step in which a plurality of holes extending in the vertical direction in the wall portion and having a lower end reaching a vertically lower side than an inner surface of the bottom portion, and the bottom portion and the An insertion step of inserting a series of reinforcing members straddling the wall portion, and an injection step of sequentially injecting two types of injection materials having different tensile strengths into the holes.

  In one aspect of the present invention, in the injection step, the first injection material and the second injection material having a higher tensile strength and a lower compressive strength than the first injection material are injected. The

  In another aspect of the present invention, in the injection step, the first injection material and the second injection material having higher tensile strength and higher compression strength than the first injection material are injected. Is done.

  In another aspect of the present invention, the first injection material is injected to a position lower than the inner surface of the bottom, and the second injection material is placed on the first injection material than the inner surface of the bottom. Inject to a higher position.

  In another aspect of the present invention, the first injection material is an inorganic injection material, and the second injection material is an organic injection material.

  In another aspect of the present invention, in the injection step, the first injection material is injected again after the second injection material is injected.

  In another aspect of the present invention, three or more kinds of injection materials having different tensile strengths are sequentially injected into each of the holes. In such an embodiment, for example, the first injection material, the second injection material, the third injection material, and the first injection material are injected in this order. At this time, the tensile strength of the second injection material is higher than that of the first injection material, the tensile strength of the third injection material is higher than that of the first injection material, and the second injection material. Lower.

  According to the present invention, reinforcement suitable for each part can be applied to each part of the concrete structure.

It is a perspective view of the box culvert which is an example of the reinforcement object. It is sectional drawing of the underground tunnel constructed | assembled by the box culvert shown by FIG. It is a perspective view of the box culvert in which the hole was formed. It is a partial expanded sectional view which shows the internal structure of a wall part. It is explanatory drawing of an insertion process. It is explanatory drawing of an injection | pouring process. It is a perspective view which shows an example of the filling state (lamination | stacking state) of an injection material. It is sectional drawing which shows an example of the filling state (lamination | stacking state) of an injection material. It is sectional drawing which shows another example of the filling state (lamination state) of an injection material.

(First embodiment)
Hereinafter, an example of an embodiment of the present invention will be described. The concrete structure in this embodiment is a box culvert 1 shown in FIG. The box culverts 1 are lined up in a row as shown in FIG. 1 and buried in the ground to construct an underground tunnel 2 for automobiles as shown in FIG. In other words, an underground tunnel 2 for an automobile is constructed by a plurality of box culverts 1 buried in the ground in an axially connected state. A single-lane roadway is provided inside the underground tunnel 2, and a single-lane roadway is also provided above the underground tunnel 2 (on the ground). Of course, a track may be laid inside the underground tunnel 2. That is, an underground tunnel for railway may be constructed by the box culvert 1. In this case, a roadway may be provided above the railway underground tunnel (on the ground) or another track may be laid.

  As shown in FIG. 1, each box culvert 1 includes a bottom portion 10, a pair of wall portions 11 erected vertically from both widthwise ends of the bottom portion 10, and opposed to the bottom portion 10, and two wall portions 11. The ceiling part 12 which connects the upper ends of each. These bottom part 10, wall part 11, and ceiling part 12 are rectangular plate shapes, respectively, and are integrally made of reinforced concrete.

  Next, a reinforcing method of the box culvert 1 that constructs the underground tunnel 2 shown in FIG. 2 will be described.

  First, the ground is excavated from above the wall 11 of the box culvert 1 in the vertical direction by using a heavy machine such as a back fork or a hammer grab or by hand digging.

  After excavating the ground to the outer surface 12a of the ceiling part 12 of the box culvert 1, as shown in FIG. 2, a plurality of holes 20 penetrating the ceiling part 12 and the wall part 11 and having the lower end 20a reaching the bottom part 10 are formed. (Drilling process). Various drilling devices 30 such as a drill device, a core boring device, and a water jet cutting device (water jet machining device) can be used for the drilling process. When a drilling device or a core boring device is used as the drilling device 30, the cross-sectional shape of the hole 20 is circular, and when a water jet cutting device (water jet machining device) is used, the cross-sectional shape of the hole 20 is a slit shape.

  As shown in FIG. 3, in the drilling step, a plurality of holes 20 are formed along the axis X of the box culvert 1 in each wall portion 11 of the box culvert 1. Further, the positions of the respective holes 20 are determined so that the plurality of holes 20 formed in the respective wall portions 11 are staggered in the horizontal cross section.

  As shown in FIG. 4, on the inner side of the wall portion 11 of the box culvert 1 (FIG. 3), the first vertical stripe 41 a extending in the vertical direction and the horizontal direction extending closer to the inner surface thereof. An inner reinforcing bar 41 is provided in which the first horizontal bars 41b are arranged in a lattice pattern. Further, on the inner side of the wall portion 11 of the box culvert 1, a second vertical bar 42a extending in the vertical direction and a second horizontal bar 42b extending in the horizontal direction are arranged in a lattice pattern near the outer surface thereof. An outer reinforcing bar 42 is provided. The hole 20 is formed between the inner reinforcing bar 41 and the outer reinforcing bar 42, that is, in a place where the existing reinforcing bars (the first vertical bars 41a, the first horizontal bars 41b, the second vertical bars 42a, and the second horizontal bars 42b) do not exist. The

  Next, as shown in FIG. 5, a series of reinforcing members 50 extending over substantially the entire length of the hole 20 is inserted into each hole 20 formed by the drilling process (insertion process). The reinforcing member 50 in the present embodiment is a reinforcing bar having the same overall length as the depth of the hole 20.

  Here, as described above, the lower end 20a of each hole 20 reaches the bottom 10 (see FIG. 2). That is, the lower end 20 a of the hole 20 is positioned below the inner surface 10 b of the bottom 10 in the vertical direction. Therefore, a series of reinforcing members 50 having the same overall length as the depth of the hole 20 straddle the bottom portion 10 and the wall portion 11. In other words, the lower end of the reinforcing member 50 inserted into each hole 20 is positioned below the bottom inner surface 10b.

  Thereafter, as shown in FIG. 6, two or more types of injection materials having different tensile strengths are injected into the respective holes 20 in which the reinforcing members 50 are inserted (injection process). Specifically, the first injection material 61 and the second injection material 62 are sequentially injected. More specifically, after the first injection material 61 is injected, the second injection material 62 is injected, and then the first injection material 61 is injected again.

  Here, the first injection material 61 is an injection material having a higher compressive strength and a lower tensile strength than the second injection material 62. In other words, the second injection material 62 is an injection material having higher tensile strength and lower compression strength than the first injection material 61. That is, in the injection process in the present embodiment, the first injection process for injecting the first injection material 61 having relatively excellent compressive strength and the second injection for injecting the second injection material 62 having relatively high tensile strength. An injection process and a third injection process for reinjecting the first injection material 61 having relatively excellent compressive strength, and the first injection process, the second injection process, and the third injection process are executed in this order. . In the following description, when there is no particular distinction between the first injection material 61 and the second injection material 62, they may be collectively referred to as “injection material 60”. FIG. 6 is an image diagram. Actually, a predetermined amount of the injection material 60 is injected into each hole 20 from the ground via a pipe, a hose or the like.

  When the above-described injection process in which two or more kinds of injection materials 60 are injected is completed, as shown in FIG. The filling material 61 is filled (laminated) in this order.

  Here, in the first injection step, the first injection material 61 is injected to a position lower than the bottom inner surface 10 b of the box culvert 1. In the second injection step, the second injection material 62 is injected onto the first injection material 61 to a position higher than the bottom inner surface 10b. In the third injection step, the first injection material 61 is injected onto the second injection material 62 up to a predetermined position (for example, the upper end of the hole 20).

  However, the inside of the hole 20 cannot be visually confirmed. Therefore, based on the volume of the hole 20 and the volume of the reinforcing member 50, the amount of the injection material 60 necessary for making the bulkiness of the injection material 60 a predetermined bulkiness is determined in advance. In the injection step, by injecting a predetermined amount of the first injection material 61 and the second injection material 62 in the above order, the first injection material 61 and the second injection material having a predetermined bulk at a predetermined position inside the hole. The injection material 62 is filled.

  Through the above steps, as shown in FIG. 8, a series of reinforcing members 50 straddling the bottom portion 10 and the wall portion 11 are inserted into the respective holes 20. Further, in the gap between the inner peripheral surface of the hole 20 and the outer peripheral surface of the reinforcing member 50 inserted into the hole 20, the first injection material 61, the second injection material 62, and the first injection material 61 are provided. It is filled in this order. The second injection material 62 is filled from a position lower than the bottom inner surface 10b to a position higher than the bottom inner surface 10b. In other words, the first injection material 61 injected in the first injection step is filled only in the bottom portion 10 of the box culvert 1, and the first injection material 61 injected in the third injection step is the wall of the box culvert 1. Only the part 11 is filled. On the other hand, the second injection material 62 injected in the second injection step is filled across the bottom 10 and the wall 11 of the box culvert 1. In other words, the second injection material 62 is filled in a corner portion between the bottom portion 10 and the wall portion 11 of the box culvert 1.

  The first injection material 61 in the present embodiment is an inorganic injection material, more specifically mortar. Further, the second injection material 62 in the present embodiment is an organic injection material, more specifically, a thermoplastic resin.

  That is, according to the reinforcing method according to the present embodiment, the second injection material 62 having relatively high tensile strength is filled in the corner portion between the bottom portion 10 and the wall portion 11 of the box culvert 1, and this second portion is filled. The first injection material 61 that is relatively excellent in tensile strength is filled above and below the injection material 62.

  As described above, in the present embodiment, the proof stress of the concrete structure is improved by injecting the second injection material 62 excellent in tensile strength into the concrete structure having inferior tensile strength as compared with the compressive strength. Furthermore, the second injection material 62 excellent in tensile strength is selectively filled in a corner portion where a compression edge and a tensile edge are generated at the same time due to a bending force during an earthquake or the like, and the other portion is excellent in compression strength. In addition, since the first injection material 61 is selectively filled, the yield strength of the entire concrete structure is improved in a well-balanced manner. As described above, according to the reinforcing method of the present embodiment in which two or more kinds of the injection material 60 are used at appropriate positions, reinforcement suitable for the respective sections can be applied to each section of the box culvert 1.

  It is also conceivable to fill other injection material superior to the injection material 60 in both compressive strength and tensile strength over the entire length of the hole 20. However, an injection material that is superior in terms of both conflicting strengths is generally expensive, and injecting such an injection material over the entire length of the hole 20 leads to an increase in the cost of reinforcement work.

  In the reinforcing method according to the present embodiment, the hole 20 is formed by accessing the box culvert 1 embedded in the ground from the ground. Further, the reinforcement member 50 is inserted into the hole 20 and the injection material 60 is injected from the ground. That is, the drilling process, the insertion process, and the injection process are all performed from the ground. Therefore, the work in the underground tunnel 2 shown in FIG. 2 is not necessary, and the work can be completed without restricting the passage of vehicles in the underground tunnel 2.

  Moreover, since the extending direction of the reinforcing member 50 is a vertical direction, it is advantageous in covering the shear fracture line in various directions assumed at the time of an earthquake, and advantageous in securing the seismic performance of the underground tunnel 2. is there. For example, when the reinforcing member extends in the thickness direction of the wall portion, the reinforcing member hardly crosses the shear fracture line extending in the same direction, and the function of the reinforcing member is not sufficiently exhibited. On the other hand, since the reinforcing member 50 in the present embodiment extends in the vertical direction (the height direction of the wall portion 11), the extending direction of the reinforcing member 50 and the shear fracture line surely intersect, The function of the reinforcing member 50 is sufficiently exhibited.

  Further, when the reinforcing member extends in the thickness direction of the wall portion, toughness reinforcement is the main effect as shear reinforcement of the wall portion, and the effect of bending reinforcement cannot be obtained. On the other hand, since the reinforcing member 50 in the present embodiment extends in the height direction of the wall portion 11, an effect of bending reinforcement is obtained as shear reinforcement of the wall portion 11.

  A number of shear reinforcements are required to cover the expected shear failure line. However, as the number of holes increases, the existing enclosure gets damaged. On the other hand, in the present embodiment in which the holes 20 are formed along the height direction of the wall portion 11, the number of the holes 20 required to cover the assumed shear fracture line is small, and the damage given to the existing housing. Can be minimized.

  As shown in FIG. 4, an inner reinforcing bar 41 and an outer reinforcing bar 42 made of a plurality of reinforcing bars arranged in a lattice shape are embedded in the wall portion 11 of the box culvert 1 (FIG. 3). Therefore, when it is going to form a hole in the thickness direction of the wall part 11, it is necessary to perforate the inner reinforcing bar 41 and the outer reinforcing bar 42. For this reason, although drilling is performed while confirming the position of the reinforcing bar by rebar search using ultrasonic waves or the like, there is a possibility that the drilling operation may be re-executed frequently due to interference with the reinforcing bar that cannot be searched by the search. However, in this embodiment, since the hole 20 is formed between the inner reinforcing bar 41 and the outer reinforcing bar 42, the possibility of interference with the reinforcing bar is extremely low.

  As shown in FIG. 3, the corner portion of the box culvert 1 is bent. Therefore, when forming the hole which extends in the thickness direction from the inner side in the wall part 11, it is difficult to form a hole in a corner part. On the other hand, in the present embodiment in which the hole 20 extending in the vertical direction from the outside is formed in the wall portion 11 of the box culvert 1, the hole 20 can be easily formed in the corner portion.

(Second Embodiment)
Next, another example of the embodiment of the present invention will be described. However, the difference between the reinforcing method according to the present embodiment and the reinforcing method according to the first embodiment is only the injection step. Therefore, hereinafter, the injection process in the present embodiment will be described in detail, while the description of the drilling process and the insertion process will be omitted.

  In the injection process in the present embodiment, three types of injection materials having different tensile strengths are sequentially injected. Specifically, the injection process in the present embodiment includes a first injection process for injecting a first injection material, a second injection process for injecting a second injection material, and a third injection for injecting a third injection material. And a fourth injection step of reinjecting the first injection material.

  The 1st injection material inject | poured by a 1st injection process and a 4th injection process is the same injection material as the 1st injection material 61 (FIG. 8) in 1st Embodiment. Further, the second injection material injected in the second injection step is the same injection material as the second injection material 62 (FIG. 8) in the first embodiment.

  On the other hand, the third injection material injected in the third injection step is an injection material having a compressive strength lower than that of the first injection material 61 and higher than that of the second injection material 62. The third injection material is an injection material having a tensile strength lower than that of the second injection material 62 and higher than that of the first injection material 61. That is, the third injection material has an intermediate property between the first injection material 61 and the second injection material 62. Examples of the third injection material include an injection material in which a resin or the like is mixed with the first injection material 61 to increase the tensile strength, or an injection material in which lime or the like is mixed with the second injection material 62 to increase the compressive strength. Etc. are used.

  When the above injection process is completed, as shown in FIG. 9, the first injection material 61, the second injection material 62, the third injection material 63, and the first injection material 61 are placed inside each hole 20. Are filled (laminated) in this order. Also in the present embodiment, the second injection material 62 is filled from a position lower than the bottom inner surface 10b to a position higher than the bottom inner surface 10b. Further, the bulk of the second injection material 62 is lower than the bulk of the third injection material 63. That is, the injection amount of the second injection material 62 is smaller than the injection amount of the third injection material 63. In the case where the third injection material 63 is an injection material that is increased in volume by mixing filler or slurry with the second injection material 62, by injecting the third injection material 63 more than the second injection material 62, The compressive strength and tensile strength of the entire structure can be improved while suppressing the amount of the high-cost second injection material 62 used.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the infusate is not limited to the infusate specified herein. For example, as the first injection material 61 in the above embodiment, high strength mortar, non-shrink mortar, cement, or the like can be used in addition to normal mortar. Moreover, a thermosetting resin or coal tar can be used for the second injection material 62 in the above embodiment. However, when a thermoplastic resin or coal tar is used as the second injecting material 62, there is an advantage that the original shape or a shape close to this can be restored by applying heat after deformation. Furthermore, each filler can be mixed with various fillers as necessary to adjust the tensile strength and the compressive strength. By such adjustment, it is possible to obtain an injection material having higher tensile strength and higher compression strength than the first injection material 61 in the above embodiment, and this injection material is used as the second injection material in the above embodiment. 62 can also be used. Thus, by using the second injection material 62 excellent in both tensile strength and compression strength in combination with the first injection material 61 and the third injection material 63, the amount of expensive injection material used is suppressed. In addition to improving the proof stress of the entire concrete structure, the toughness of the corner portion can be improved.

  The reinforcing member is not limited to a reinforcing bar. For example, a steel plate such as an H-shaped steel or an I-shaped steel can be used for the reinforcing member. Further, a reinforcing bar may be wound around the steel plate as the reinforcing member.

  As the reinforcing member, a cylindrical or rectangular tube-shaped reinforcing bar, a cylindrical or rectangular tube-shaped steel pipe, a flat steel plate, or the like can be used, and a number of holes may be formed in the steel pipe or the steel plate. That is, a perforated steel pipe or a perforated steel plate can also be used as a reinforcing member. Furthermore, you may arrange | position the fiber tube which consists of a high-strength fiber material inside a perforated steel pipe. Various reinforcing members as described above may be used alone or in combination.

  Moreover, you may avoid adhering a reinforcement member and an injection material by providing a friction reducing material on the surface of a reinforcement member. Such treatment is advantageous in preventing shear failure of the wall portion in which the reinforcing member is embedded.

  The concrete structure that can be reinforced by the reinforcing method of the present invention is not limited to a box culvert. For example, the reinforcing method of the present invention can be applied to reinforcing a wall portion (side wall) of a digging road constructed by hitting concrete in a groove excavated in the ground or by arranging precast members. The reinforcing method of the present invention can also be applied to the reinforcement of the wall portion (vertical wall) of the retaining wall that stands up from the bottom portion (floor slab).

  The present invention can be applied not only to the reinforcement of an undamaged concrete structure, but also to the reinforcement (repair) of a concrete structure damaged by an earthquake or the like. In this case, it is possible to effectively repair and reinforce internal cracks that cannot be confirmed from the outside or are difficult to confirm.

1 Box culvert 2 Underground tunnel 10 Bottom 10b Inside (bottom)
DESCRIPTION OF SYMBOLS 11 Wall part 12 Ceiling part 12a Outer surface 20 Hole 20a Lower end 30 Drilling device 41 Inner reinforcing bar 41a 1st vertical bar 41b 1st horizontal bar 42 Outer bar 42a 2nd vertical bar 42b 2nd horizontal bar 50 Reinforcement member 60 Injection material 61 1st injection | pouring Material 62 Second Injection Material 63 Third Injection Material X Axis

Claims (6)

A method of reinforcing a concrete structure comprising a bottom and a wall portion standing vertically from the bottom, embedded in the ground,
A drilling step of forming a plurality of holes extending in the vertical direction in the wall portion and having a lower end reaching vertically downward from the inner surface of the bottom portion;
An insertion step of inserting a series of reinforcing members straddling the bottom portion and the wall portion into each of the holes;
Each of said holes, possess a first injection material, a second injection material tensile strength than injection material of the first high, and an injection step of successively injecting in this order, a,
The first injection material is mortar, and the second injection material is a thermoplastic resin.
A method of reinforcing concrete structures. In the reinforcement method of the concrete structure of Claim 1,
The thermoplastic resin as the second injection material has a higher tensile strength and a lower compression strength than the first injection material ,
A method of reinforcing concrete structures. In the reinforcement method of the concrete structure of Claim 1,
The thermoplastic resin as the second injection material has a higher tensile strength and a higher compression strength than the first injection material ,
A method of reinforcing concrete structures. In the reinforcement method of the concrete structure of Claim 2 or 3,
Injecting the first injection material to a position lower than the inner surface of the bottom,
Injecting the second injection material onto the first injection material to a position higher than the inner surface of the bottom,
A method of reinforcing concrete structures. In the reinforcing method of the concrete structure of any of claims 2-4,
In the injection step, after injecting the second injection material, the first injection material is injected again.
A method of reinforcing concrete structures. A method of reinforcing a concrete structure comprising a bottom and a wall portion standing vertically from the bottom, embedded in the ground,
A drilling step of forming a plurality of holes extending in the vertical direction in the wall portion and having a lower end reaching vertically downward from the inner surface of the bottom portion;
An insertion step of inserting a series of reinforcing members straddling the bottom portion and the wall portion into each of the holes;
In each of the holes, a first injection material, a second injection material having a tensile strength higher than that of the first injection material, a tensile strength higher than that of the first injection material, and the second injection material. An injection step of sequentially injecting a third injection material lower than the material in this order ,
The first injection material is mortar, and the second injection material is a thermoplastic resin.
A method of reinforcing concrete structures.

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