JP5020876B2 - Support member and fixing method of the support member - Google Patents

Description

  The present invention relates to a support member fixed to a natural ground in order to effectively suppress deformation of the natural ground and expansion of a plastic region, and a fixing method of the support member.

  Rock bolts are used as supporting members when building mountain tunnels. The rock bolt is used to obtain a restraining effect on the natural ground by fixing the natural ground so that the ground is deformed inward and tension is applied and cracks of the rock are not moved. Therefore, the lock bolt is a stand-by support member that exhibits a support function only when the tunnel wall surface or ground is deformed. Therefore, in the current technology, a certain amount of displacement must be allowed in order to exert the effect.

  There are two types of lock bolts, a fixing material type and a friction type, depending on the fixing method. In the fixing material type, a hole filled with a lock bolt is filled with a fixing material such as cement mortar, and then the lock bolt is inserted to fix the lock bolt by solidifying the fixing material. There are a method and a post-injection method in which a fixing material such as cement milk or resin is injected after a lock bolt is inserted into the hole, and the fixing material is solidified to fix the lock bolt. These all use a fixing material.

  On the other hand, the friction type is a method of fixing by a frictional force obtained by bringing the lock bolt into close contact with the hole wall. In this method, a slit spring type forcibly inserting a lock bolt having a diameter larger than the diameter of the drilled hole, and injecting high-pressure water into the hole to inflate the steel pipe to closely contact the hole wall. There is an expanded steel pipe type.

  In recent years, expanded steel pipe type lock bolts having unique flexibility such as deformation according to the shape of the hole wall and a wide application range have been adopted. This is because the corrosion problem which has been considered as a problem has been solved by adopting the high corrosion resistance plating (see Non-Patent Document 1).

Since this expansion steel tube type lock bolt does not use a fixing material, it can complete the lock bolt work with few steps, such as drilling, insertion of the lock bolt, and expansion by injection of high-pressure water, and it can be installed at low cost. is there.
Hidemasa Ota, Seiji Inokuma, Toshiharu Tachibana, "New method of slope countermeasures-Drainage reinforcement pipes / expanded steel pipe type rock bolts", [online], August 25, 2004, Japan Society for Landslide Research, [2008] Search on March 18, 2009], Internet <URL: http://www.chiyoda-kizai.co.jp/PN/siken/2004JLS_OHTA.pdf>

  In order to more effectively suppress the deformation of the natural ground and the expansion of the plastic zone, it is necessary to restrain the natural ground positively and early by applying pre-stress instead of the above-described standby-type support member. Pre-stress means applying a force in advance, specifically, applying a compressive force in advance to a place where a tensile force is applied, or applying a tensile force in advance to a place where a compressive force is applied. In addition, the prestress can be introduced into the natural ground by fixing the rock bolt with the prestress applied.

  However, immediately after tunnel excavation, prestressing the rock bolt with the face has the following problems. The filler used in the construction of the fixing material type rock bolt is slow in curing time and cannot be prestressed immediately after excavation. Although it is possible to shorten the curing time by using a special chemical solution, in this case, it cannot be applied at low cost.

  There are examples of applying prestressed rock bolts as reinforcement for deformed tunnels after completion. This is because there is a time margin and the machine used is relatively unconstrained in proportion to the application during tunnel excavation. However, immediately after tunnel excavation, there is a risk of collapse of the natural ground, so there is no time allowance, and heavy machines are not workable and take time, so there are restrictions on the machines used. is there.

  In addition, since the friction type lock bolt does not use a fixing material, it can be constructed in a short time, but the slit spring type is fixed only by inserting, and the expanded steel pipe type is inflated by injecting water. Since it is fixed, the prestress cannot be applied to the lock bolt.

  For this reason, immediately after tunnel excavation, it is possible to easily and quickly fix to a natural ground without using a fixing material, and to provide a support member capable of giving prestress, and a fixing method using the support member The provision of

  As a result of intensive studies, the inventors of the present invention constructed a structure in which two or more expanded steel pipe-type lock bolts are connected in the longitudinal direction thereof, inserted into the drilled hole, and the leading expansion inserted first. After injecting water into only the steel pipe type lock bolt and inflating it, and bringing it into close contact with the hole wall, pulling on the subsequent expanded steel pipe type lock bolt connected to the leading expansion pipe type lock bolt, It has been found that prestressing can be introduced by injecting water into an expanded steel pipe type lock bolt and expanding, and can be easily and quickly fixed to a natural ground without using a fixing material.

The above-described problems can be solved by providing the support member and the support member fixing method of the present invention. That is, according to the present invention, in order to prevent the collapse of the tunnel wall surface, the support member is inserted and fixed in a hole drilled in the tunnel wall surface,
Two or more rod-shaped bag bodies that are inflated by injecting water into the inside and are in close contact with the hole wall are connected in the longitudinal direction of the rod-shaped bag body,
After pouring water into the first rod-shaped bag body inserted first into the hole and bringing it into close contact with the hole wall, the subsequent rod-shaped bag body connected to the first rod-shaped bag body is pulled while pulling in the direction in which the subsequent rod-shaped bag body is pulled out. A support member is provided, which is characterized in that water is poured into a rod-shaped bag body and brought into close contact with a hole wall. What is injected into the inside is not limited to water, but may be a liquid such as oil.

  As said rod-shaped bag body, it can be set as an expanded steel pipe type | mold lock bolt. When this expanded steel pipe type lock bolt is adopted, it has a washer and nut for fastening to the natural ground, a hole through which the expanded steel pipe type lock bolt can be inserted, and is arranged between the tunnel wall surface and the washer. A ring-shaped bag body that expands by pouring water and expands the distance between the tunnel wall surface and the washer is further provided.

  Further, according to the present invention, it is possible to provide a method for fixing a support member in a hole that has been drilled. This method includes the steps of inserting into the hole a support member formed by connecting two or more rod-shaped bag bodies that are inflated by injecting water into the inside thereof and are in close contact with the hole wall in the longitudinal direction of the rod-shaped bag body; Injecting water into the top rod-shaped bag body that is inserted first into the inside and inflating it to closely adhere to the hole wall, pulling the subsequent rod-shaped bag body connected to the top rod-shaped bag body in the direction of pulling out the subsequent rod-shaped bag body And injecting water into the following rod-shaped bag body and bringing it into close contact with the hole wall.

  In the step of fixing the above-mentioned succeeding rod-shaped bag body, a ring-shaped bag body is disposed between the tunnel wall surface and the washer, and the ring-shaped bag body is inflated by pouring water into the ring-shaped bag body, and the interval between the tunnel wall surface and the washer is increased. Includes an expansion step.

  By providing the support member and fixing method of the present invention, prestress can be applied immediately, and the support member can be applied quickly.

  Further, since no fixing material is required, the yield strength can be exhibited immediately after the steel pipe is expanded.

  Furthermore, by using a ring-shaped bag body, prestress can be applied without using heavy machines such as center hole jacks and torque wrenches, so workability is good and construction time is greatly reduced. Can do.

  The support member and fixing method of the present invention will be described in detail with reference to the drawings. Tunnels are constructed by shield method, mountain method (NATM), etc., but excavation reduces the strength of natural ground and tends to collapse. For this reason, concrete is sprayed on the tunnel wall surface formed by excavation, and excavation of the tunnel is performed while fastening and reinforcing the natural ground with a supporting member such as a rock bolt. During the tunnel excavation, the support member of the present invention is inserted into the hole after being drilled on the tunnel wall surface using a boring machine, a rock drill, or the like, and is fixed to restrain the natural ground. The structure is formed by connecting two or more rod-shaped bag bodies that expand by pouring water into the inside thereof in the longitudinal direction. It should be noted that the inside of the rod-shaped bag body is not limited to water, and liquid such as oil can also be supplied. Hereinafter, the description will be made assuming that water is supplied into the rod-shaped bag body.

  FIG. 1 is a view showing one embodiment of a support member of the present invention. In FIG. 1, two expanded steel pipe type lock bolts 11, 12 are connected in the longitudinal direction to form a support member 10, and each lock bolt 11, 12 is made of steel having a corrosion-resistant plated surface. This foldable tube expands when high-pressure water is injected. A material made of zinc-aluminum-magnesium alloy or the like is used for the corrosion-resistant plating. The high-pressure water may be any pressure as long as the steel tube can expand, but is supplied at a water pressure of about 20 to 50 MPa, for example.

  The support member 10 is threaded at the end when the end to be inserted into the hole is the tip, and the nut 13 is screwed together. The support member 10 is fastened to a natural ground by a nut 13 and is formed of a thin plate having a substantially square flat surface in which a hole through which a lock bolt can be inserted is formed between the tunnel wall surface and the nut 13. A washer 14 is disposed. This washer 14 is provided to prevent the nut 13 from getting into the tunnel wall surface and to prevent the nut 13 from loosening due to seismic motion or the like. Further, the support member 10 includes water inlets for individually pouring water into the lock bolts 11 and 12, and the lock bolts 11 and 12 can be individually expanded. In addition, since each lock bolt 11 and 12 expand | swells, in order to hold | maintain an expansion | swelling shape, it is not necessary to hold | maintain the water supplied to the inside, and the water inlet may remain open.

  FIG. 2 is a cross-sectional view of the support member 10 shown in FIG. The lock bolts 11 and 12 have expansion portions 20 and 21 and screw portions 22 and 23 that enable the nut 13 to be screwed together. The inflating portions 20 and 21 are steel rod-shaped bags and are in a deflated state before injecting high-pressure water, but expand and expand in diameter when injecting high-pressure water. The screw portions 22 and 23 have screw threads and screw grooves formed on the surface thereof so that the nut 13 can be screwed together, and the inside of the screw portions 22 and 23 forms a continuous water injection channel to the expansion portions 20 and 21. Has been. Here, the configuration including the screw portions 22 and 23 is illustrated, but when the cap is used instead of the nut 13, the screw portions 22 and 23 may not be provided.

  In order to inflate only the leading lock bolt 11 after inserting the leading lock bolt 11 inserted first into the hole and the succeeding lock bolt 12 connected thereto into the hole, A tube 24 extending from the end of the threaded portion 22 to the end of the threaded portion 23 of the subsequent lock bolt 12 protruding from the tunnel wall surface is separately provided. In addition, if it protrudes from a tunnel wall surface and can be connected with a water injection pump, it does not need to extend to the terminal of said screw part 23. FIG. The tube 24 passes through the inside of the expansion portion 21 of the subsequent lock bolt 12, passes through the screw portion 23 of the subsequent lock bolt 12, or passes through the expansion portion 21 of the subsequent lock bolt 12. They can be arranged in parallel. In FIG. 2, as an example, a tube 24 is provided through the thread portion 23 of the subsequent lock bolt 12. The details will be described with reference to FIG.

  In FIG. 3A, the tube 24 is provided through the inside of the expansion portion 21 of the subsequent lock bolt 12 and through the screw portion 23 of the subsequent lock bolt 12. The water injection pump is connected to the tube 24 first, injects water only to the leading lock bolt 11 and expands it, and causes the expansion portion 20 of the leading lock bolt 11 to adhere to the hole wall. Next, a water injection pump is connected to the threaded portion 23 of the subsequent lock bolt 12, the subsequent lock bolt 12 is pulled, and the subsequent lock bolt 12 is kept in tension, and water is injected from the water injection port of the subsequent lock bolt 12, The expansion portion 21 of the subsequent lock bolt 12 is in close contact with the hole wall. After these close contact, the washer 14 is passed through the threaded portion 23 of the subsequent lock bolt 12 protruding from the tunnel wall surface, and the nut 13 is screwed together, so that the support member 10 is held in place while the subsequent lock bolt 12 is in tension. To conclude.

  After the fastening, the stress is released, and a force to restore the subsequent lock bolt 12 in a direction opposite to the pulled direction is applied, and prestress is introduced into the ground. Since the soil in the vicinity of the tunnel wall surface 31 is pulled to the inside of the natural ground by the support member 10, the restraint effect of the natural mountain can be enhanced and the collapse of the tunnel wall surface can be more effectively suppressed.

  In FIG. 3B, the tube 24 is provided so as to pass through one end of the expansion portion 21 of the subsequent lock bolt 12 and to be arranged in parallel with the screw portion 23 of the subsequent lock bolt 12. Also in this case, the water injection pump is connected to the tube 24 first, injects water only to the head lock bolt 11 and expands it, and causes the expansion portion 20 of the head lock bolt 11 to adhere to the hole wall. Next, a water injection pump is connected to the threaded portion 23 of the subsequent lock bolt 12, the subsequent lock bolt 12 is pulled, and the subsequent lock bolt 12 is tensioned, and water is injected into the subsequent lock bolt 12 and expanded. Then, the expanding portion 21 of the subsequent lock bolt 12 is brought into close contact with the hole wall. After these close contact, the washer 14 is passed through the threaded portion 23 of the subsequent lock bolt 12 protruding from the tunnel wall surface, the nut 13 is screwed, and the support member 10 is put into the ground while the subsequent lock bolt 12 is kept in tension. Conclude. In this case as well, prestress is introduced into the natural ground.

  FIG. 4 shows a state where the expansion portion 20 of the lock bolt 11 is expanded. FIG. 4A is a cross-sectional view showing a deflated state at the stage where the lock bolt 11 is inserted into the bolt hole 30. Since the lock bolt 11 at this time has no water inside, the diameter of the lock bolt 11 is smaller than the diameter of the bolt hole 30 in a deflated state. In FIG.4 (b), the place where water injection is started and water is supplied inside is gradually expanded. In FIG. 4B, since the high-pressure water continues to be supplied, the lock bolt 11 is in close contact with the hole wall of the bolt hole 30 and continues to press the surrounding soil.

  FIG. 4 (c) is a view showing the place where water injection is stopped and the nut 13 is fastened. When the water injection is stopped and the nut 13 is fastened through the washer 14, the lock bolt 11 receives earth pressure from the surroundings and is fixed to the ground.

  As described above, the support member of the present invention is formed by connecting two or more expanded steel pipe type lock bolts in the longitudinal direction. Pre-stress cannot be introduced with one expanded steel pipe type lock bolt, but it is inserted first by connecting two or more expanded steel pipe type lock bolts in the longitudinal direction and enabling water injection to each. It is possible to introduce prestress by fixing it to the hole wall with the expanded steel pipe type lock bolt and pouring water while pulling the remaining expanded steel pipe type lock bolt connected thereto in the longitudinal direction. By introducing prestress in this way, the natural ground is actively restrained, and as a result, the collapse of the tunnel wall surface, the deformation of the natural ground and the expansion of the plastic area can be effectively suppressed.

  In the above description, an example in which two expanded steel pipe type lock bolts are connected is illustrated. However, in the present invention, three or more expanded steel pipe type lock bolts may be connected. The diameter of the lock bolt can be, for example, about 36 mm in the deflated state and about 54 mm in the expanded state. For example, the length of the inflatable portion can be about 1 m. About a thread part, it can be set as the length required in order to pass a washer and to screw a nut like about 0.1-0.3m.

  With reference to FIG. 5, a fixing method using a support member formed by connecting two or more expanded steel pipe type lock bolts in the longitudinal direction will be described. First, as shown to Fig.5 (a), the bolt hole 30 is drilled in the predetermined location of the tunnel wall surface 31 toward the inside of a natural ground. A plurality of bolt holes 30 are formed radially from the inside to the outside of the arch-shaped tunnel. The interval can be, for example, about every 1 m. When the diameter of the rock bolts 11 and 12 in a deflated state is about 36 mm and the diameter when expanded by pouring water is about 54 mm, the bolt hole 30 is formed with a diameter larger than 36 mm and smaller than 54 mm. Specifically, it is about 42 mm. The reason for forming such a diameter is that it can be easily inserted in a deflated state and must be in close contact with the hole wall in an expanded state.

  Next, as shown in FIG. 5B, the support member 10 in a state where the lock bolts 11 and 12 are deflated is inserted into the bolt hole 30. Then, as shown in FIG. 5 (c), water is poured into the first lock bolt 11 inserted first, and only the first lock bolt 11 is inflated and brought into close contact with the hole wall to be fixed to the ground. .

  Thereafter, as shown in FIG. 5D, the subsequent lock bolt 12 connected to the leading lock bolt 11 is pulled in the direction indicated by the arrow A. Then, a force in the direction indicated by the arrow A acts on the leading lock bolt 11 that is in close contact with the hole wall, but the leading lock bolt 11 generates a frictional force between the hole and the hole. Then, the subsequent lock bolt 12 is pulled in the direction indicated by the arrow A, and prestress is applied. Next, as shown in FIG. 5 (e), with the subsequent lock bolt 12 pulled in the direction of the arrow A, water is poured into the subsequent lock bolt 12, the lock bolt 12 is expanded, Let it settle. When three or more expanded steel pipe type lock bolts are connected, after that, the third expanded steel pipe type lock bolt is poured in water in the same manner, and expanded to be fixed on the ground.

  After fixing all the lock bolts 11 and 12, as shown in FIG. 5 (f), the stress is released, the washer 14 is passed through the threaded portion 23 of the lock bolt 12 protruding from the tunnel wall surface 31, and the nut 13 is attached. Screw and fasten to the ground. Then, the tension of the succeeding lock bolt 12 that has been tensioned by being pulled is applied with the force to restore in the direction opposite to the arrow A, and this acts on the natural ground, Prestress is introduced.

  In the embodiment shown in FIG. 5, the prestress on the lock bolt 12 is applied by pulling the lock bolt 12. However, as in the conventional case, the prestress is applied by using a center hole jack or a torque wrench. Can do.

  By using the support member 10 having the above configuration, fixing can be performed in a short time without using a fixing material such as mortar or cement milk, and prestress can be introduced into the natural ground. The support member 10 is used for support work immediately after tunnel excavation, but can also be used as a reinforcement measure after completion of the tunnel.

  In the above embodiment, a center hole jack or a torque wrench is used as a method of applying prestress. Since these are heavy, workability is bad and there exists a problem that construction takes time. Moreover, in order to inject and inflate the lock bolts 11 and 12, a water injection pump for injecting high-pressure water is used.

  Therefore, this water injection pump can be used effectively, prestress can be easily applied, and a lightweight ring-shaped bag body can be used. This ring-shaped bag body has a structure like a floating ring, with the threaded portion 23 of the lock bolt 12 passing through the center hole, and in a deflated state between the tunnel wall surface 31 and the washer 14. The lock bolt 12 is prestressed by being arranged and expanding by being filled with water and expanding the interval between the washer 14 and the tunnel wall 31.

  This ring-shaped bag body is connected to a water injection pump and has a water injection port for water injection. The material is stretchable, has a predetermined strength so as not to burst easily, and is lightweight and waterproof. It is supposed to have. Again, a check valve can be provided at the water inlet. In consideration of the above points, this bag is made of rubber such as acrylic rubber, acrylonitrile butadiene rubber, isoprene rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber, styrene butadiene rubber, butadiene rubber, fluorine rubber, and polyisobutylene. Although preferable, it may be made of FRP (Fiber Reinforced Plastics) or the like with small expansion and contraction.

  With reference to FIG. 6, the fixing method of the lock bolt using this ring-shaped bag body is demonstrated. Bolt hole 30 is drilled, and support member 10 formed by connecting two or more expanded steel pipe type lock bolts in the longitudinal direction is inserted into bolt hole 30 in a deflated state, and the first lock bolt inserted first. The procedure up to the procedure of pouring water into No. 11 and inflating it to fix it on the ground is the same as above.

  Thereafter, as shown in FIG. 6 (a), the ring-shaped bag body 32 in a deflated state is passed through the threaded portion 23 protruding from the tunnel wall surface 31 of the subsequent lock bolt 12, and then the washer 14 is passed through. Screw together. The nut 13 is screwed so that the washer 14 is in a predetermined position. The position of the washer 14 with respect to the tunnel wall surface 31 is a position where the ring-shaped bag body 32 expands and the subsequent lock bolt 12 can be pulled appropriately. At this stage, the ring-shaped bag body 32 is disposed between the tunnel wall surface 31 and the washer 14.

  As shown in FIG. 6 (b), before water is injected into the subsequent lock bolt 12 connected to the leading lock bolt 11, water is injected into the ring-shaped bag body 32 through the water injection port 33, and this ring-shaped bag body. 32 is inflated. As a result, the ring-shaped bag 32 is brought into close contact with the tunnel wall 31 and the washer 14 by this expansion and presses both of them, widening the distance between the tunnel wall 31 and the washer 14 and pulling the lock bolt 12. For this reason, tension is applied to the lock bolt 12 and prestress is applied. While continuing to inject water into the ring-shaped bag body 32 and maintaining this state, as shown in FIG. The bolt 12 is expanded and fixed to the natural ground.

  After injecting water into each of the lock bolts 11 and 12, as shown in FIG. 6D, the water inside the ring-shaped bag body 32 is extracted, the nut 13 is screwed, and the support member 10 is fastened to the natural ground. . In addition, the nut 13 can be screwed and fastened while extracting the water inside.

  Thus, by utilizing the water injection pump effectively using the ring-shaped bag body 32, the workability of the support member can be improved and the construction time can be shortened.

  The supporting member and the fixing method of the supporting member of the present invention have been described in detail with reference to the embodiment shown in the drawings so far, but the present invention is not limited to the above-described embodiment, and other Embodiments, additions, changes, deletions, and the like can be changed within the scope that can be conceived by those skilled in the art, and any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited. Is. For example, although the arrangement of the tube 24 is illustrated in FIG. 3, the arrangement is not limited to this, and any arrangement and tube size can be used as long as the water can be appropriately injected and the inflating portions 20 and 21 can be appropriately inflated. It may be.

The figure which showed one Embodiment of the supporting member of this invention. Sectional drawing of the supporting member shown in FIG. The figure which showed arrangement | positioning of the tube for water injection in detail. The figure which showed the cross section of the expansion part of an expansion steel pipe type | mold lock bolt. The figure which showed one construction procedure which fixes the support member of this invention to a natural ground. The figure which showed another construction procedure which fixes the support member of this invention to a natural ground.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Support member, 11, 12 ... Lock bolt, 13 ... Nut, 14 ... Washer, 20, 21 ... Expansion part, 22, 23 ... Screw part, 24 ... Tube, 30 ... Bolt hole, 31 ... Tunnel wall surface, 32 ... Ring-shaped bag, 33 ... Water inlet

Claims (6)

In order to prevent the collapse of the tunnel wall surface, a support member inserted and fixed in a hole drilled in the tunnel wall surface,
Two or more rod-shaped bag bodies that are expanded by injecting water or oil into the inside thereof and closely contacting the hole wall are connected in the longitudinal direction of the rod-shaped bag body,
Water or oil is injected into the leading rod-shaped bag body inserted first into the hole and brought into close contact with the hole wall, and then the trailing rod-shaped bag body connected to the leading rod-shaped bag body is replaced with the trailing rod-shaped bag body. A supporting member, wherein the supporting member is in contact with the hole wall by injecting or injecting water into the following rod-shaped bag while pulling in the pulling-out direction.   The support member according to claim 1, wherein the rod-shaped bag body is an expanded steel pipe type lock bolt. The support member has a washer and a nut for fastening the expanded steel pipe type lock bolt to the tunnel wall surface, and a hole through which the expanded steel pipe type lock bolt can be inserted, and between the tunnel wall surface and the washer. A ring-shaped bag body to be disposed;
The supporting member according to claim 2, wherein the ring-shaped bag body expands by pouring water or oil into the ring-shaped bag body to expand a distance between the tunnel wall surface and the washer. In order to prevent the collapse of the tunnel wall surface, the support member is fixed in the hole drilled in the tunnel wall surface,
Inserting the support member formed by connecting two or more rod-shaped bag bodies that are inflated by injecting water or oil into the inside thereof and are in close contact with the hole wall in the longitudinal direction of the rod-shaped bag body;
Injecting or inflating water into the top rod-shaped bag body inserted first into the hole to inflate, and sticking the top rod-shaped bag body to the hole wall;
And a step of injecting or injecting the trailing rod bag body connected to the leading rod bag body into the trailing rod bag body while closely pulling the trailing rod bag body in the direction in which the trailing rod bag body is pulled out.   The method according to claim 4, wherein the rod-shaped bag body is an expanded steel pipe type lock bolt.   The step of fixing the succeeding rod-shaped bag body includes passing the ring-shaped bag body and a washer through the expanded steel pipe type lock bolt, and screwing a nut into the expanded steel pipe type lock bolt to thereby form the tunnel wall surface and the washer. Including the step of disposing the ring-shaped bag body between the two and expanding the space between the tunnel wall surface and the washer by injecting or injecting water into the ring-shaped bag body. The method according to claim 4 or 5.

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