JP2007239300A - Rock bolt and method of driving rock bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rock bolt capable of eliminating complicated operations when the rock bolt is driven despite the fact that it is simply formed and having a very high corrosion resistant effect. <P>SOLUTION: The rock bolt body 10 is formed of a steel bar having a screw-shaped node on the peripheral surface thereof. The area of the rock bolt body from the end 10a thereof projecting from the surface G1 of the slope of a sloped ground G to 150 mm below the sloped ground G is set as a head part corrosion resistant part P. A grease layer formed by coating with grease and a heat-shrunk film layer covering the grease layer and held on the peripheral surface P1 of the head part corrosion resistant part P are formed on the peripheral surface P1 of the head part corrosion part P. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rock bolt that is placed in order to stabilize a slope whose surface layer is likely to collapse, and an installation method of the lock bolt.

Conventionally, in stable construction of sloped ground such as mountain retaining work, a fixing tool for earth retaining may be installed for the purpose of preventing landslide of the sloped ground. In the case where the fixing tool is installed on the inclined ground, a method for preventing the landslide of the inclined ground is provided in which the fixing tool is fixed by driving a lock bolt composed of a steel rod (for example, Patent Document 1). When installing a fixing tool using a lock bolt in this way, the lock bolt is driven into an insertion hole provided in the inclined ground by drilling, and a cement system is placed around the installed lock bolt. Grout is injected and this lock bolt is fixed to the inclined ground. In addition, this cementitious grout is inject | poured to the surface of a slope.
JP 2005-314993 A

  On the other hand, in the section of the rock bolt that is buried in the injected cement grout, it is not touched by external water or air because it is buried in the injected cement grout. As a result, the section buried in the cement-type grout of this rock bolt was hardly oxidized and corroded. On the other hand, in the non-grout buried section protruding outside from the surface of the slope of this rock bolt, it is not buried in the cement-type grout, so that it is exposed to the external environment. As a result, there remains a problem that the non-grouting buried section of the rock bolt is liable to oxidize and corrode due to contact with water such as rain or external air.

  In order to solve such a problem, an installation method in which the lock bolt 100 is driven on the inclined ground G as shown in FIG. 6 is provided. This lock bolt installation method is a method in which a pipe-like sheath 102 is covered with a non-grouting buried section protruding outside from the surface of the slope of the lock bolt main body 101. That is, when the cement grout 103 is injected into the insertion hole 104, the pipe-shaped sheath 102 that covers the distal end portion side of the placed lock bolt 100 is also partially buried. According to such a construction method, the pipe-shaped sheath 102 blocks the non-grout buried section exposed to the outside of the lock bolt main body 101 so as not to touch water such as rain. As a result, the above-described anticorrosion effect can be expected. Reference numeral 105 denotes a fixing tool that presses the inclined ground G. Reference numeral 106 denotes a nut portion that is screwed into the distal end portion of the driven lock bolt main body 101.

  However, in such a construction method, a part of the base end side is buried in the cement grout 103 in a state where the pipe-shaped sheath 102 described above is along the axial direction of the lock bolt main body 101. Therefore, complicated workability has been pointed out due to the precise positioning work when the sheath 102 is installed. In addition, the above-described locked bolt 100 may not be driven in a direction perpendicular to the slope. In such a case, a gap is generated between the fixing tool 105 and the sheath 102. It will be easy to do and watertightness will be impaired. Specifically, there has been a problem that rainwater enters from a gap generated between the fixing device 105 and the sheath 102.

  The present invention has been made in view of the above-described circumstances, and while being able to be easily configured, it eliminates the complexity of work for placing a lock bolt and has a very high anticorrosion effect. It is to provide a lock bolt and an installation method of the lock bolt.

In order to solve the above problems, the present invention provides a lock bolt and a lock bolt installation method according to the following means.
The lock bolt according to claim 1 is a lock bolt that is placed in order to prevent landslide of the inclined ground, and a lock bolt main body that is formed of a steel rod having a screw-shaped node on the outer peripheral surface; A nut portion screwed into a tip portion protruding from the surface of the slope ground surface of the rock bolt body, and the tip portion protruding from the surface of the slope ground surface of the lock bolt body. From the slope of the sloped ground to at least 150 mm buried in the sloped ground is set as a head anticorrosion part, and the outer peripheral surface of the head anticorrosion part is formed by applying grease. And a heat-shrinkable film layer that covers the grease layer and holds the grease on the outer peripheral surface of the head anticorrosion part. In the tip portion of the bets body, characterized in that it is screwed over the anticorrosion layer.

  In the lock bolt according to the present invention, the section of the lock bolt body from the tip portion protruding from the slope surface of the slope ground to at least 150 mm buried in the slope ground from the slope face of the slope ground. Set as a part anticorrosion part, on the outer peripheral surface of the head anticorrosion part, a grease layer formed by applying grease, and heat shrinkage that covers this grease layer and holds the grease in the head anticorrosion part Since the anticorrosion layer provided with the mold film layer is provided over the entire circumference, the anticorrosion layer can block contact of the head anticorrosion portion of the lock bolt body with water and air. The grease layer blocks the head anticorrosion portion from being exposed to water and air, and further blocks the heat shrinkable film layer from being exposed to water and air.

  In addition, this heat shrinkable film layer is a film layer formed by heat shrinkage unlike a mere film layer, so that the air between the lock bolt body can be expelled to the outside during this heat shrinkage. And can be brought into close contact with the lock bolt body. Moreover, the opening part of both ends can also be obstruct | occluded preferably. Accordingly, the grease forming the grease layer can be firmly held by the heat shrinkable film layer, and the head anticorrosion portion can be more effectively shielded from water and air.

  Therefore, in this rock bolt body, the non-grouting buried section protruding outside from the slope surface of the inclined ground is composed of a part of the head anticorrosion part, and this head anticorrosion part is buried in the cement grout. As with the section to be used, it does not come into contact with water, air, etc., and is less susceptible to oxidation corrosion. Moreover, the grease which forms this grease layer is preferably held on the outer peripheral surface of the head anticorrosion part without being discharged to the outside by being covered with the heat shrinkable film layer.

  Further, as described above, since the head anticorrosion part is set in a section from the tip part to at least 150 mm buried in the inclined ground, a part where the anticorrosion layer is provided and a part buried in the cement grout, Will be overlapped. As a result, even if there is a slight error in the amount of burying of the placed lock bolt body, there is a margin of at least 150 mm in the part of the burial, which alleviates accuracy requirements due to the placement. Can improve the convenience during construction. In addition, in this lock bolt, since the anticorrosion effect could be provided without using the pipe-shaped sheath as described above, it was not necessary to use the pipe-shaped sheath, and the sheath was used. It is possible to omit complicated steps such as positioning (coaxial positional relationship, etc.) in the process, and the convenience in construction can be improved.

  The lock bolt installation method according to claim 2 is a lock bolt installation method for preventing the landslide of the inclined ground, wherein the lock bolt main body is made of a steel rod having a screw-shaped node on the outer peripheral surface. A section extending from the slope protruding from the slope surface of the sloped ground to at least 150 mm buried in the sloped ground from the slope of the sloped ground is set as a head protection part. A grease layer forming step of forming a grease layer by applying grease to the outer peripheral surface of the portion, and a tube having heat shrinkability on the head anticorrosion portion so as to cover the grease layer on the outer peripheral surface of the head anticorrosion portion A tube covering step for covering the film-like film, and heat-shrinking the tube-shaped film placed on the head anticorrosion part to heat-shrink the both end openings of the tube-shaped film into the lock bolt body. A heat-shrinkable film layer forming step of forming a heat-shrinkable film layer formed by covering and closing the grease layer and covering the grease layer; and a base end side of the anticorrosion layer on the inclined ground A placing step of placing the lock bolt on the inclined ground so as to be disposed below the surface of the slope, and a base end side of the anticorrosion layer of the placed rock bolt is buried in a cement grout. As described above, after the grout injection step of injecting the cement grout to the surface of the slope of the sloped ground, and after the cemented grout injected has solidified, a fixing tool is laid on the slope of the sloped ground, A nut screwing step in which a nut portion is screwed from above the anticorrosion layer to a tip end portion of the lock bolt on which the anticorrosion layer is formed.

  In the installation method of the lock bolt according to the present invention, the anticorrosive layer is provided on the head anticorrosion part with the grease layer forming step, the tube covering step, and the heat shrinkable film layer forming step, so that only 3 In the process, the anticorrosion layer can be provided on the lock bolt body without using any special equipment or harmful solvent. In addition, when the heat shrink temperature of the tube-shaped film having heat shrinkability is set to hot water temperature, the tube film is heat-shrinked by applying hot water in the heat shrinkable film layer forming step. be able to. Accordingly, when the anticorrosion layer is provided on the head anticorrosion part of the lock bolt, it can be easily performed at the site, so that it is excellent in convenience that does not require complicated work and special equipment.

  Moreover, in forming this heat-shrinkable film layer, a tube-like film having heat-shrinkability is selected, so that both ends of the tube-like film are subjected to heat-shrinking so that the lock bolt body Can be brought into close contact with the main body of the lock bolt so as to close the gap therebetween. Furthermore, since the heat-shrinkable film layer is formed by heat shrinking the tube-shaped film, air can be expelled to the outside at the time of this heat shrinking, and the lock bolt body should be securely adhered. Can do. As a result, the grease forming the grease layer is held by the heat-shrinkable film layer in which the opening portions at both ends are preferably closed, and the grease does not flow out to the outside. In this case, the grease can be held firmly. Therefore, this head anticorrosion part can be more effectively shielded from water and air.

  Further, in the method of installing the lock bolt according to the present invention, the placing step of placing the lock bolt on the inclined ground so that the base end side of the anticorrosive layer is disposed below the surface of the slope of the sloped ground. And a grout injection process for injecting cement grout up to the surface of the sloped ground so that the base end side of the anticorrosive layer of the rock bolt that is placed is buried in the cement grout, and the injected cement grout Since the fixing tool is laid on the slope of the sloped ground and the nut portion is screwed onto the tip portion of the lock bolt on which the anticorrosion layer is formed, from the top of the anticorrosion layer. The conventional process of installing a pipe-like sheath can be omitted, and the complexity in construction is eliminated. In addition, the non-grouting buried section that protrudes outward from the sloped surface of the inclined ground is composed of a part of the head anticorrosion part, and there is no need to use toxic chemical materials or separate equipment, and in addition, complicated processes Without being necessary, it can be provided with antioxidative corrosion resistance (corrosion resistance). Therefore, since the anti-corrosion property can be imparted to the lock bolt by this installation method, the overall useful life can be extended for a long period of time as compared with the conventional case.

  Further, as described above, since the head anticorrosion part is set in a section from the tip part to at least 150 mm buried in the inclined ground, a part where the anticorrosion layer is provided and a part buried in the cement grout, Will be overlapped. As a result, even if there is a slight error in the amount of burying of the placed lock bolt body, there is a margin of at least 150 mm in the part of the burial, which alleviates accuracy requirements due to the placement. Can improve the convenience during construction. In addition, in this lock bolt, since the anticorrosion effect could be provided without using the pipe-shaped sheath as described above, it was not necessary to use the pipe-shaped sheath, and the sheath was used. It is possible to omit complicated steps such as positioning (coaxial positional relationship, etc.) in the process, and the convenience in construction can be improved.

  In this screwing step, before the nut portion is screwed to the tip of the lock bolt, grease is further applied to the outer peripheral surface of the anticorrosion layer, and a second grease layer is formed on the anticorrosion layer. You may do it. When the second grease layer is formed on the outer peripheral surface of the anticorrosion layer as described above, it is possible to further block water and air, and even if the nut portion is screwed, the second grease layer can be blocked. It can be screwed smoothly by the grease of the grease layer. Further, in the above-described screw fitting step, an appropriate cushion member for leveling the slope may be laid before the fixing tool is installed. This cushion member may be configured in an appropriate bag shape configured such that cement milk can be injected therein.

  According to the lock bolt and the lock bolt installation method according to the present invention, while being easily configured, it eliminates the complexity of the work for placing the lock bolt and has a very high anticorrosion effect. The service life can be extended for a long time.

  Hereinafter, embodiments of a lock bolt and a lock bolt installation method according to the present invention will be described with reference to the drawings. 1 is a perspective view of the lock bolt, FIG. 2 is a cross-sectional view showing an example in which the lock bolt of FIG. 1 is placed on an inclined ground, and FIG. 3 is a partial view showing a head anticorrosion portion of the lock bolt main body of FIG. FIG. 4 is a cross-sectional view, FIG. 4 is a diagram showing a process of performing anticorrosion treatment on the lock bolt, and FIG.

  Reference numeral 1 in the perspective view of FIG. 1 indicates a lock bolt that is placed in order to prevent landslide of the inclined ground. The lock bolt 1 is roughly divided into a lock bolt main body 10 composed of a long steel rod, and a tip portion (an end portion on the side protruding from the surface G1 of the sloped ground G to the outside). It is comprised from the nut part 40 screwed by 10a. The lock bolt main body 10 is a so-called threaded steel rod (for example, D19 to D29 manufactured by Tokyo Steel Co., Ltd.) having a screw-shaped node (hereinafter referred to as a screw node) 11 formed on the outer peripheral surface. ing. The screw node 11 provided on the outer peripheral surface is a male screw that can be screwed with an appropriate clearance with respect to the female screw 42 provided inside the nut portion 40 to be screwed. . The screw nodes 11 are continuously formed at appropriate intervals along the axis X direction (length direction) of the lock bolt main body 10.

  Further, the screw node 11 is not provided over the entire circumference of the lock bolt main body 10, but is formed with a flat smooth surface portion 12 and about 45 degrees in the circumferential direction (¼ circumferential surface). Alternatingly arranged. The smooth surface portion 12 is provided on the outer peripheral surface of the lock bolt main body 10 along the axis X direction of the lock bolt main body 10. In addition, this smooth surface part 12 is arrange | positioned on the surrounding surface which has the same diameter as the trough of a screw node.

  The size of the lock bolt main body 10 in the illustrated example will be described. The diameter is set to about 20 mm, and the length is set to an appropriate length according to the place to be driven. As shown in the cross-sectional view of FIG. 2, a section with an embedding amount of 200 mm buried in the inclined ground G from the slope of the inclined ground G is set as the head anticorrosive part P from the tip portion 10a. Reference numeral 21 denotes a fixing tool installed along the slope of the inclined ground G. The head anticorrosion part P is appropriately set in consideration of the thickness of the laid cushion member, the fixing tool 21 and the like. Moreover, the outer peripheral surface P1 of this head anticorrosion part P is a location where the anticorrosion layer 30 which interrupts | blocks the lock bolt main body 10 so that external water and air may not be touched is provided. That is, the head anticorrosion part P is not buried in the cement grout S injected into the insertion hole 20 out of the rock bolt main body 10 placed in the drilled insertion hole 20, and is formed on the inclined ground G. It is a non-grouting buried section that protrudes to the outside from the sloped surface G1.

  As shown in the partial cross-sectional view of FIG. 3, the anticorrosion layer 30 includes a grease layer 31 formed by applying grease over the entire circumference of the outer peripheral surface P1 of the head anticorrosion portion P, and the grease. The heat-shrinkable film layer 35 that covers the grease layer 31 is configured to hold the grease forming the layer 31 on the outer peripheral surface P1 of the head anticorrosion part P. The grease layer 31 is configured with an appropriate thickness, and the heat-shrinkable film layer 35 is not expanded or contracted, and a material that is not easily torn is selected.

  The grease constituting the grease layer 31 constituting the anticorrosion layer 30 is made of a material having a property of blocking water and air. For example, an appropriate grease such as a wax type or a petrolatum type having excellent anticorrosion properties is used. Is selected. As the grease constituting the grease layer 31, an appropriate material having a property of blocking air and water can be selected. However, in consideration of water and air blocking properties, a wax-based material can be easily formed in a layer shape. Especially preferred are greases such as those of petrolatum. Further, an appropriate thickness can be selected as the thickness of the layer, but in this example, it is set to about 2 mm. In addition, although it does not attach | subject a code | symbol in particular, on the outer peripheral surface of this heat shrinkable film layer 35, a 2nd grease layer may be newly provided by apply | coating grease. When this second grease layer is formed, water and air are more effectively blocked by the characteristics of the grease.

  Further, the heat shrinkable film layer 35 covers the grease layer 31 so as to be held on the outer peripheral surface P1 of the head anticorrosion part P so that the grease constituting the grease layer 31 does not flow outside. The heat-shrinkable film layer 35 in this example is configured by heat-shrinking a tube-shaped film having heat-shrinkability, and the distal end (opening) portion 30a and the base end (opening) portion 30b are rock bolts. The main body 10 is in close contact with the gap so as to close the gap. Accordingly, the grease constituting the grease layer 31 is preferably held on the outer peripheral surface P1 of the head anticorrosion part P without flowing out from the distal end part 30a or the base end part 30b. Further, as the material constituting the heat shrinkable film layer 35, a material that is less likely to generate friction is selected, and the material is not easily broken by friction. For the heat shrinkable film layer 35, it is desirable to select a material having shrinkability so that the openings at both ends are closed by shrinkage in view of preventing the grease constituting the grease layer 31 from flowing out to the outside. In particular, those that shrink by heat are preferable from the viewpoint of workability.

  A nut portion 40 having a female screw 42 (see FIG. 2) that is screwed with a screw node (male screw) 11 of the lock bolt main body 10 is screwed into the distal end portion 10 a of the lock bolt main body 10. Note that the female screw 42 of the nut portion 40 that is screwed into the distal end portion 10a of the lock bolt main body 10 is screwed into the male screw formed on the outer peripheral surface of the lock bolt main body 10 with an appropriate clearance. An appropriate groove width is set. By setting the appropriate groove width in this manner, when the nut portion 40 is screwed into the distal end portion 10a of the lock bolt body 10, a load such as friction is applied to the heat shrinkable film layer 35 described above. The heat shrinkable film layer 35 is not damaged. Although not particularly illustrated, as described above, appropriate grease is applied to the outer peripheral surface of the heat-shrinkable film layer 35 or the portion where the female screw 42 of the nut portion 40 is formed. Two grease layers may be formed. Thus, when the 2nd grease layer is formed, when the nut part 40 is screwed by the front-end | tip part 10a of the lock bolt main body 10, this heat shrinkable film layer 35 is made hard to damage more, and is preferable. .

  In the lock bolt 1 described above, the entire circumference of the outer peripheral surface of the lock bolt main body 10 is included in the head anticorrosion part P (including a part buried in the cement-type grout) that is a non-grouting section. The contact between the head anticorrosion part P and the water or air that is used as the external environment is blocked by the properties unique to the grease layer 31 formed by applying the grease. As a result, the head anticorrosion part P that is not buried in the cement-based grout S does not come into contact with air and water that cause oxidative corrosion in the same manner as the part that is buried in the cement-based grout S. It becomes the lock bolt with the property.

  In addition, the grease forming the grease layer 31 is preferably held on the outer peripheral surface P1 of the head anticorrosion part P without being discharged outside by being covered with the heat shrinkable film layer 35. That is, the grease that forms the above-described grease layer 31 is securely and firmly held on the outer peripheral surface P1 of the head anticorrosion part P, and the anticorrosion property of the head anticorrosion part P is preferably maintained. Further, as described above, the head anticorrosion part P is set as a head anticorrosion part P from the tip part 10a to the section from the slope of the inclined ground G to the buried amount 200 mm buried in the inclined ground G. Therefore, although it is a portion protruding from the surface G1 of the slope of the inclined ground G, it does not come into contact with water, air, etc. like the section buried in the cement grout S, and it is difficult to oxidize and corrode. .

  Further, unlike the mere film layer, the heat shrinkable film layer 35 is a film layer formed by heat shrinkage, so that the air between the lock bolt body 10 is expelled to the outside during the heat shrinkage. And can be securely brought into close contact with the lock bolt main body 10. Moreover, the opening part of both ends can also be obstruct | occluded preferably. Accordingly, the grease forming the grease layer 31 can be firmly held by the heat shrinkable film layer 35, and the head anticorrosion part P can be more effectively shielded from water and air.

  Furthermore, since this head anticorrosion part P is set in the section from the front-end | tip part 10a of the rock bolt main body 10 to the embedding amount 200mm buried in the inclined ground G, the location where the anticorrosion layer 30 is provided, and cementitious grout The part buried in S is overlapped. As a result, even if an error occurs in the buried amount of the rock bolt body 10 that has been laid, the portion to be buried has a margin of 200 mm, so the anti-corrosion layer 30 is provided in the non-grouting buried section. The head anticorrosion part P can be used. In addition, the burial amount 200 mm buried in the slope ground G from the slope of the slope ground G is only an example, and if such a burial amount of at least 50 mm, preferably 150 mm or more is secured, such accuracy The effect of relaxation can be achieved.

  Therefore, accuracy requirements due to placement can be relaxed, and convenience during construction is enhanced. In addition, in this lock bolt, since the anticorrosion effect could be provided without using the pipe-shaped sheath as described above, it was not necessary to use the pipe-shaped sheath, and the sheath was used. It is possible to omit complicated steps such as positioning (coaxial positional relationship, etc.) in the process, and the convenience in construction can be improved.

  Next, the anticorrosion method according to the present invention, which is a method for providing the anticorrosion layer 30 on the outer peripheral surface P1 of the head anticorrosion part P of the lock bolt main body 10 described above, will be described. As shown in the process diagram of FIG. 4, this anticorrosion method is roughly divided into a grease layer forming process (FIG. 4A), a tube covering process (FIG. 4B), and a heat shrinkable film layer forming process. (FIG. 4C). In addition, in the figure, only the front-end | tip part 10a side arrange | positioned in the rock bolt main body 10 near the slope of the inclined ground G is shown.

  First, the grease layer forming process will be described. In this grease layer forming process, as shown in FIG. 4A, the grease is applied to the entire circumference of the outer peripheral surface P1 of the head anticorrosive part P described above. The grease layer 31 (see FIG. 3) is formed by application using a method such as the above. As the grease forming the grease layer 31, an appropriate grease can be selected as described above.

  And after the grease layer formation process mentioned above is complete | finished next, as shown in FIG.4 (b), it moves to a tube covering process. In this tube covering step, a tubular film (heat shrinkable) having heat shrinkability on the head anticorrosion part P so as to cover the grease layer 31 formed over the entire circumference of the outer peripheral surface P1 of the head anticorrosion part P. The state 35a before covering) is put on. As the tubular film 35a, an appropriate one can be selected, but when thermally contracted, the openings 36a and 36b at both ends thereof are preferably in close contact with the lock bolt body 10, and the open state is closed. The size and material to be selected are selected. The tubular film 35a is made of a material that thermally shrinks at a hot water temperature.

  After this tube covering step is completed, the process moves to a heat shrinkable film layer forming step for forming a heat shrinkable film layer 35 that covers the grease layer 31, as shown in FIG. In this heat shrinkable film layer forming step, the tube-shaped film 35a covered on the head anticorrosion part P in the tube covering step is subjected to heat shrinkage by applying hot water or the like. Accordingly, the openings 36 a and 36 b at both ends thereof are closed so as to be in close contact with the lock bolt main body 10, thereby forming a heat shrinkable film layer 35 that covers the grease layer 31 while being in close contact with the grease layer 31. Specifically, in the tube covering step described above, the tube-shaped film 35a covered on the head anticorrosion part P is thermally contracted by applying hot water heated by the kettle Y or the like. In addition, the extra length part in the opening part 36a on the tip side is cut and processed after being thermally contracted. Thus, the anticorrosion layer 30 provided with the grease layer 31 and the heat-shrinkable film layer 35 covering the grease layer 31 is provided in the head anticorrosion part P of the lock bolt body 10. And if the nut part 40 is screwed to the front-end | tip part 10a of this lock bolt main body 10, it will become the lock bolt 1. FIG.

  In this anticorrosion method of the lock bolt, since the anticorrosion layer 30 is provided on the head anticorrosion part P having a grease layer forming step, a tube covering step, and a heat shrinkable film layer forming step, there are only three steps. Thus, the anticorrosion layer can be provided on the lock bolt body 10 without using any special equipment or harmful solvent. In the heat-shrinkable film layer forming step, when the tube-shaped film 35a is heat-shrinked, it is only necessary to add hot water to the tube-shaped film 35a, and no complicated work or special equipment is required. . In addition, when the tube-shaped film 35a having heat shrinkability is selected in forming the heat shrinkable film layer 35, the air between the lock bolt body 10 is expelled to the outside by heat shrinking, The openings 36a and 36b at both ends are brought into close contact with the lock bolt main body 10 so as to block the grease 21 from flowing out. Accordingly, it is possible to omit the complicated construction work for blocking, and it is possible to close the grease layer 31 without causing the grease of the grease layer 31 to flow out without fail.

  Next, with respect to the lock bolt 1 in which the anticorrosion layer 30 is provided on the head anticorrosion part P by the anticorrosion method described above, the lock bolt installation method for preventing the landslide of the inclined ground G will be described with reference to FIG. explain. The anticorrosion method and the following installation method are combined to provide the lock bolt installation method according to the present invention. As described above, this lock bolt installation method is a driving step in which the lock bolt 1 provided with the anticorrosion layer 30 by the anticorrosion method is placed in the insertion hole 20 drilled in the inclined ground G (FIG. 5A )), A grout injection step (FIG. 5 (b)) for injecting cement-based grout S into the insertion hole 20 in which the lock bolt 1 is placed, and a fixing tool 21 is laid on the slope of the inclined ground G ( 5 (c)) and a nut screwing step (FIG. 5 (d)) for fixing the fixing device 21 by screwing the nut portion 40 to the tip portion 10a of the lock bolt 1.

  Specifically, in the placing step, as shown in FIG. 5A, the lock bolt 1 is inserted into the insertion hole 20 formed by drilling the inclined ground G, and the inclined ground G is driven. When the lock bolt 1 is driven, a part of the lock bolt 1 on the base end portion 30b side of the anticorrosion layer 30 provided in the head anticorrosion portion P is a surface G1 of the slope of the inclined ground G. The lock bolt 1 is driven inside the inclined ground G so as to be disposed further downward. Thus, after driving the lock bolt 1 to the inclined ground G, the process then proceeds to the grout injection process.

  In the grout injection process, as shown in FIG. 5B, the cement-type grout S is injected into the insertion hole 20 in which the lock bolt 1 is placed. The cement-type grout S is injected in the above-described casting step, in which the part of the base end portion 30b side of the anticorrosion layer 30 located below the surface G1 of the sloped ground G slope is injected into the cement. Cement grout S is injected into the insertion hole 20 so as to be buried in the system grout S. That is, the cement grout S is injected until the surface G1 of the slope of the inclined ground G is reached. In addition, in this cement grout S, an appropriate thing can be selected. After injecting this cementitious grout S, the process proceeds to a nut screwing step.

  In the nut screwing step, as shown in FIG. 5C, after the injected cement grout S is solidified, the fixing tool 21 is laid on the slope of the inclined ground G. Specifically, the tip end portion 1a of the lock bolt 1 protruding from the solidified cement grout S (also serving as the tip portion 10a of the lock bolt main body 10) is inserted into the insertion hole 22 provided in the center of the fixing tool 21. To do. Then, as shown in FIG. 5 (d), the nut portion 40 is screwed onto the tip end portion 1 a of the lock bolt 1 to fix the fixing tool 21 to the slope of the inclined ground G. Before the nut portion 40 is screwed onto the distal end portion 1a of the lock bolt 1, grease is applied to the outer peripheral surface 30c of the anticorrosion layer 30 provided on the lock bolt 1 to form a second grease layer. It may be done. In this way, the portion of the rock bolt 1 that protrudes from the solidified cement grout S is a three-layer structure of the grease layer 31, the heat shrinkable film layer 35, and the nut portion 40, or the grease layer 31, It has a four-layer structure of a shrinkable film layer 35, a grease layer (second grease layer not shown), and a nut portion 40, and the heat shrinkable film layer 35 is less likely to be damaged and further has an anticorrosive effect. It becomes. In addition, even if an appropriate process such as a cushion member laying process for flattening the inclined ground G is provided in the nut screwing process, it does not depart from the spirit of the present invention.

  In this method of installing the lock bolt, the step of installing a conventional pipe-shaped sheath can be omitted, and the lock bolt 1 can be easily installed. It has such a very high anticorrosion property. Therefore, since the rock bolt can be easily installed and improved in oxidation corrosion, the service life can be extended for a long time.

In addition, this invention is not limited to said embodiment, In the range which does not deviate from the meaning of this invention, appropriate selection and addition can be made.
For example, the lock bolt main body described in the above-described embodiment is composed of a steel rod having a screw-shaped node having a diameter of 20 mm. The lock bolt main body which constitutes is not limited to this example, and may be constituted with an appropriate diameter. In other words, the diameter of the lock bolt main body may be selected according to the site where it is placed without any problem even if any diameter such as 15 to 50 mm is selected.

It is a perspective view of a lock bolt. FIG. 2 is a cross-sectional view showing an example in which the lock bolt of FIG. 1 is driven on an inclined ground. It is a partial cross section figure which shows the head anticorrosion part of the lock bolt main body of FIG. It is a figure which shows the anticorrosion process of a lock bolt. It is a figure which shows the installation process of a lock bolt. It is a perspective view of the conventional lock bolt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rock bolt 10 Rock bolt main body 10a Tip part 20 Head anticorrosion part 21 Grease 30 Anticorrosion layer 31 Grease layer 35 Heat shrinkable film layer G Inclined ground S Cement grout

Claims (2)

It is a lock bolt that is placed to prevent the landslide of sloped ground,
A lock bolt main body made of a steel rod having a node formed in a screw shape on the outer peripheral surface, and a nut portion screwed into a tip portion protruding from the surface of the slope of the slope ground of the lock bolt main body,
Of the rock bolt body, a section from the tip portion protruding from the surface of the slope ground surface to at least 150 mm buried in the slope ground from the slope surface of the slope ground is set as a head anticorrosion portion. ,
A grease layer formed by applying grease to the outer peripheral surface of the head anticorrosion part, and a heat shrinkable type that covers the grease layer and holds the grease on the outer peripheral surface of the head anticorrosion part An anticorrosion layer provided with a film layer is provided,
The lock bolt, wherein the nut portion is screwed onto the anticorrosion layer at the tip end portion of the lock bolt body. It is an installation method of lock bolts to prevent landslide of inclined ground,
Of the rock bolt body made of a steel rod having a screw-shaped node on the outer peripheral surface, it is buried in the inclined ground from the slope surface of the inclined ground from the tip portion protruding from the surface of the slope ground surface. Set the section up to at least 150mm as the head anticorrosion part,
Applying grease on the outer peripheral surface of the head anticorrosion part to form a grease layer, and a grease layer forming step,
A tube covering step of covering the head anticorrosion part with a tubular film having heat shrinkability so as to cover the grease layer on the outer peripheral surface of the head anticorrosion part;
By heating and shrinking the tube-shaped film placed over the head anticorrosion part, both end openings of the tube-shaped film are brought into close contact with the lock bolt main body and closed with the grease layer. A heat-shrinkable film layer forming step of forming a heat-shrinkable film layer formed by coating the grease layer;
A placing step of placing the lock bolt on the sloped ground so that the base end side of the anticorrosive layer is disposed below the surface of the slope of the sloped ground;
A grout injection step of injecting the cement-based grout to the surface of the slope of the sloped ground so that the base end side of the anticorrosion layer of the rock bolt that has been placed is buried in the cement-based grout;
After the injected cementitious grout has solidified, a fixing tool is laid on the slope of the sloped ground, and a nut portion is screwed onto the tip of the lock bolt where the anticorrosion layer is formed from above the anticorrosion layer. A lock bolt installation method comprising: a nut screwing step for fitting.

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