JP5311453B2 - Ground reinforcement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a natural ground reinforcing method for forepiling work, face reinforcing work, etc., which reinforces the front natural ground when e.g. a tunnel, an underground opening, etc. are excavated, which enhances adhesion at the weak material age of a cement-based consolidation material for anchoring a reinforcing pipe as a reinforcing material, which prevents the outflow and runway of the consolidation material even in the production of sump water, which can bring about a great anchoring force even in the fragile condition of the natural ground by increasing rigidity so as to enhance a reinforcing effect. <P>SOLUTION: In this natural ground reinforcing method, a drilled hole (h) is formed at a predetermined angle of elevation in the natural ground 1 ahead of a cutting face from inside a tunnel excavation space T; concurrently with that, a reinforcing pipe 6, which is formed by sequentially connecting one or more pipes with an ejection hole for the consolidation material to a peripheral wall, is driven into the drilled hole (h); and an anchoring or consolidation area 8 is formed for reinforcement in the reinforcing pipe 6 and the natural ground 1 around it by injecting the consolidation material into the reinforcing pipe 6. Characteristically, a material, in which glass fibers are mixed into the cement-based consolidation material such as cement milk and cement mortar, is used as the consolidation material. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a natural ground reinforcing method such as a tip receiving work or a mirror reinforcing work that reinforces a front natural ground when excavating a tunnel, an underground cavity or the like.

  Conventionally, when excavating a tunnel in a fragile ground having poor geological conditions, the tunnel has been dug while reinforcing the ground in front of the face. In the natural ground reinforcement method (the face reinforcement method) for excavating a tunnel while reinforcing the ground in front of the face in advance, as described in Patent Documents 1 and 2 below, In order to prevent exfoliation, a tip receiving work that forms a tip receiving material that is an arch-shaped ground reinforcing body using a reinforcing pipe on the outer periphery of the tunnel from the face to the front ground, and to suppress the extrusion behavior in front of the face There is a mirror reinforcement work to reinforce the tunnel excavation area, which is a natural ground in front of the face mirror part.

  These natural ground reinforcement methods use a standard drilling machine such as a hydraulic drill jumbo, which is generally used for mountain tunnel construction methods, so-called double drilling of a cylindrical drilling rod and a reinforcing pipe placed around it. It has been practiced to reinforce a natural mountain by making a drilling hole by a pipe method and accommodating and arranging a reinforcing pipe in the drilling hole. In other words, a cylindrical drilling rod with a drilling bit at the tip is drilled at a predetermined elevation in the ground in front of the face, and at the same time, the drilling rod is disposed around it. After sequentially pulling the reinforcing tube into the drilling hole, a cemented or resin-based consolidated material is injected into the reinforcing tube to form a consolidated region in the reinforcing tube and the surrounding natural ground for reinforcement. Is. In this case, as the reinforcing pipe, a steel pipe or a resin pipe having a discharge hole for a consolidated material on the peripheral wall is used. For example, a plurality of pipes having a diameter of about 100 mm and a length of about 3000 mm are sequentially drawn into the drilling hole. Alternatively, the reinforcing pipe may be formed of a long single pipe.

  FIG. 9 shows a conventional example in which the above natural ground reinforcement method is applied to the receiving work A, and the double pipe as described above is placed in the natural ground 1 in the upper front part of the face 1a in the tunnel excavation space T. The hole h is formed by a method or the like, and at the same time, a reinforcing pipe 6 made of a steel pipe or the like is accommodated in the hole h, and a consolidated region 8 is formed in the reinforcing pipe 6 and in the surrounding ground 1. This is a reinforced natural ground in front of the face 1a. FIG. 10 shows a conventional example in which the above-described ground reinforcement method is applied to the mirror reinforcement B. In the ground 1 in front of the face 1a of the tunnel excavation space T, the double pipe as described above is provided. The hole h is formed by a method or the like, and at the same time, a reinforcing pipe 6 made of a resin pipe or the like is accommodated in the hole h, and a consolidated region 8 is formed in the reinforcing pipe 6 and in the surrounding ground 1. And reinforced the ground in front. These forehead and mirror reinforcement works are designed to reinforce in the drilling hole h formed in the natural ground 1 for the purpose of suppressing the preceding loosening of the natural ground by constraining the natural ground in front of the face for a long time. By placing the pipe 6, the front ground is reinforced, and the solidified material is injected into the ground 1 around the hole wall through the reinforcing pipe 6, thereby enhancing the restraint of the ground.

  When injecting the caking material as described above, after the reinforcing pipe is installed at a predetermined position, a waste cloth, urethane caulking seal or the like is arranged in advance on the outer periphery of the reinforcing pipe 6 on the opening end side of the hole h. Then, the opening end is closed, or a packer made of a cloth bag or the like is arranged on the outer periphery of the end portion of the reinforcing pipe 6, and urethane partition resin is injected into the packer and expanded to form a partition wall. The leakage of the consolidated material from the opening end side is suppressed. In addition, cement-based, urethane-based or other resin-based consolidated materials are used as the above-mentioned consolidated materials to fix the ground around the reinforcing pipe and the hole wall and suppress axial stress. The stability of the front ground is improved.

JP-A-8-121073 JP-A-4-357293

  By the way, when a tunnel is dug into a weak ground such as unconsolidated or soft rock, the ground 1 in the broken line region 1s in FIG. A natural ground behavior (extrusion behavior) occurs in the direction of pushing out to the face 1a side. Therefore, in the construction method in which a consolidation material is injected into a reinforcement pipe placed in the above-described drilling hole, and a consolidation region is formed and fixed in the reinforcement pipe and the surrounding natural ground, FIG. In addition to the state in which the front ground has been reinforced by the leading construction A and mirror reinforcement construction B as shown in a), the reinforcement pipe remains in the front of the face after the next tunnel excavation area is excavated as shown in FIG. It is necessary to maintain the state fixed to the mountain and to effectively exhibit the axial rigidity and shear rigidity of the reinforcing pipe.

  However, as a caking material for fixing the above-mentioned reinforcing pipe and the like, generally a cement-based caking material is often used, and a relatively long curing time is required until the caking material is sufficiently hardened. If the curing time from the injection of the binder to the next tunnel excavation is lengthened at the time of construction, it is difficult to ensure sufficient curing time because the construction efficiency is greatly reduced. Therefore, depending on the natural ground conditions, sufficient adhesion strength is not obtained, or in the state where a sufficiently large natural ground consolidation area cannot be secured around the hole wall, and the settlement with the natural ground is a slight penetration area However, tunnel excavation must proceed to the extent that is secured, and there is a risk that poor fixing will occur and a sufficient reinforcing effect will not be obtained.

  Therefore, there is a method of using a urethane-based consolidated material having a high strength development and a high fixing effect, but has the following problems. In particular, when spring water is generated from the hole wall where the reinforcing pipe is installed, if only a conventional cement-based consolidated material is used, the consolidated material is drilled by the spring before it congeals or hardens. Although there is a possibility that fixing failure may occur due to escape from the inside or cracks in the hole wall, the use of a urethane-based solidifying material can eliminate or reduce the above-mentioned problems. However, since the urethane-based consolidated material is more expensive than the cement-based consolidated material, there is a problem that the construction cost increases.

  Furthermore, in general, if the strength of the consolidated material is not sufficient at an early age, the adhesion strength is insufficient, and the natural ground cannot be sufficiently supported at the start of tunnel excavation, but the initial strength is emphasized. Urethane or ultra-high strength cement-based consolidated materials have difficulty in workability. In other words, the rapid onset of strength means that the curing starts quickly. For example, in an extreme case, the curing has already started in the pump or the injection tube when the injection operation is completed, so careful handling is required. Become.

  The present invention was made in order to solve the above-mentioned problems, and the purpose thereof is to improve the adhesive strength at the time of weak material age of the cement-based consolidated material for fixing the reinforcing pipe as described above, Even when spring water is generated, it prevents the outflow and runaway of the consolidated material, and enhances the reinforcement effect by improving the rigidity of the consolidated material. The purpose is to provide a natural ground reinforcement method that can gain strength.

In order to achieve the above object, the ground reinforcement method according to the present invention has the following configuration. That is, it is formed by drilling at a predetermined elevation angle from the tunnel excavation space into the ground in front of the face at the same time, and simultaneously connecting a single pipe or a plurality of pipes each having a discharge hole for a consolidated material on the peripheral wall. In a natural ground reinforcement construction method in which a reinforcing pipe is placed in the drilling hole, and a consolidated material is injected into the reinforcing pipe to form a fixing or consolidated area in the reinforcing pipe and surrounding natural ground. As the above-mentioned solidification material, a cement-type solidification material such as cement milk or cement mortar mixed with glass fiber is used . A glass fiber reinforced resin tube is used as a single tube or a plurality of tubes which are mixed at a ratio of 0 to 2.0 % by weight and form the entire length of the reinforcing tube.

  As described above, according to the present invention, since the cement consolidation material mixed with glass fiber is used as the injection consolidation material of the face reinforcement in a fragile ground condition during tunnel excavation, When the above-mentioned consolidated material is infiltrated and fixed in the reinforcing tube placed in and around the surrounding ground, the glass fibers in the above-mentioned consolidated material are dispersed with each other, or between the glass fibers and the reinforcing tube or The natural ground congeals and hardens while tangling with each other. Therefore, it is possible to reliably increase the strength and rigidity and adhesion resistance of the consolidated material when it is young.

  Moreover, as said glass fiber, a thing with a length of 2-10 mm mixes in the ratio of 0.3-5 weight%, more preferably 1.0-2.0 weight% in a cement-type solidified material, It is possible to satisfactorily block voids such as opening cracks existing in the hole wall, thereby suppressing the outflow and escape of the cement-based consolidated material. In addition, even if the consolidated material is affected by spring water before it congeals and hardens, the flow resistance of the cement-based consolidated material is increased by glass fiber, so it is possible for it to flow away with the spring water as much as possible. It becomes possible to reduce.

  Hereinafter, the ground reinforcement method according to the present invention will be described in detail based on the embodiment shown in the drawings. FIG. 1 (a) is a longitudinal sectional view of a tunnel in which a receiving work and a mirror reinforcing work are being constructed by the ground reinforcement method according to the present invention, FIG. 1 (b) is a transverse sectional view thereof, and FIG. It is an enlarged longitudinal cross-sectional view of a part of a front receiving work and a mirror reinforcement work.

  In the present embodiment, when excavating a tunnel in a fragile natural ground, in order to ensure the stability of the face 1a, a hole h is provided in the front ground 1 of the face 1a, and the reinforcing material is inserted into the hole h. This is applied to the long tip receiving work A and the long mirror reinforcing work B for restraining the natural ground 1 by the reinforcing pipe 6, and a cement-based solidified material containing glass fiber is injected into the reinforcing pipe 6 A consolidation region 8 made of the above-mentioned consolidation material is formed in the reinforcement pipe 6 and in the surrounding natural ground to reinforce the front natural ground 1 of the face 1a.

  In the embodiment shown in the figure, a long mirror reinforcement is already placed in the ground in front of the face in order to suppress the face behavior during tunnel excavation. A drill jumbo 9 is arranged near the upper half face of the tunnel, and the tip of the guide shell 9a of the drill jumbo 9 is set under a steel support that has already been built in the immediate vicinity of the face mirror after tunnel excavation. ing. In this embodiment, a primary shot concrete 2 having a predetermined thickness is applied to the face mirror part 1a of the tunnel excavation space T that has already been excavated, and between the steel supports 4b and 4b built in the upper part of the tunnel excavation space T. Is provided with secondary sprayed concrete 4a.

  A drill rod 3 is attached to the guide shell 9a in a state of being connected to the rock drill 5, and a steel support on the face 1a side is supported by a drill bit (not shown) provided at the tip of the drill rod 3. A hole h is formed in the front ground 1 at a predetermined elevation angle from the lower side of the work 4b, and at the same time, the reinforcing pipe 6 disposed around the hole rod 3 as the hole rod 3 moves forward is provided with the above-mentioned hole. The holes are sequentially drawn into the hole h. The reinforcing pipe 6 is also driven in the same manner as described above on the mirror reinforcing work B below the receiving work A configured as described above. The material and length of each of the reinforcing pipes 6 of the receiving work A and mirror reinforcing work B are appropriate, but in the present embodiment, the length is 13.5 m FRP pipe (fiber reinforced resin pipe), particularly GFRP. A tube (glass fiber reinforced resin tube) is used.

  Further, in this embodiment, a porous pipe 6a for forming a bulkhead is provided at the rear end portion (end portion on the face 1a side) of each of the reinforcing pipes 6 of the above-described receiving construction A and mirror reinforcement construction B in order to suppress leakage. By injecting urethane with high permeability from a packer injection pipe (not shown) into a packer (not shown) provided in the perforated pipe 6a, a bulk is put in the ground surrounding the porous pipe 6a. A head region 7 is formed. Then, a caking material is injected from the injection pipe 10 into each reinforcing pipe 6 on the deeper side of the hole than the porous pipe 6a, and is cut from the discharge holes formed in the respective reinforcing pipes 6 and the peripheral walls of the respective reinforcing pipes 6. The solidified region 8 is formed by penetrating and solidifying the above solidified material into the surrounding natural ground 1 through the hole h. In the figure, reference numeral 12 denotes an exhaust pipe for discharging the air remaining in the reinforcing tube 6 and the drilling hole h to the outside of the drilling hole h when the consolidated material is injected into the reinforcing tube 6.

  In the present invention, the above-mentioned consolidated material is a mixture of glass fibers in a cement-based consolidated material such as cement milk or cement mortar. In the above embodiment, the consolidated material is a premixed mortar. In the cement-based consolidated material, a glass fiber having a length of 2 to 10 mm mixed at a ratio of 0.5 to 5% by weight is used.

  As described above, when a cement-based consolidated material mixed with glass fiber is used as a solidified material for the ground reinforcement method such as the receiving work A or the mirror reinforcing work B, it is struck into the hole h. When the above-mentioned consolidation material is infiltrated and fixed in the reinforcing tube 6 and the surrounding natural ground 1, the glass fibers in the above-mentioned consolidation material are dispersed, or the glass fibers are reinforced with each other. The tube or ground pile congeals and hardens while tangling with each other. As a result, a consolidated region 8 in which the reinforcing tube 6 and the ground 1 are firmly integrated is formed, and the strength and rigidity and adhesion resistance of the consolidated material at a young age and thereafter are increased by the glass fiber. It can certainly be increased.

  Moreover, when the glass fiber having a length of 2 to 10 mm as described above is mixed in the cement-based consolidated material in a proportion of 0.3 to 5% by weight, more preferably 1.0 to 2.0% by weight. Even if there is a gap such as an opening crack in the hole wall of the drilling hole h, the fiber can be satisfactorily plugged in the gap to suppress the outflow and escape of the cement-based consolidated material, and the consolidation Even when the material is affected by spring water before it congeals and hardens, the flow resistance of the cement-based consolidated material is increased by glass fiber, so the above-mentioned consolidated material is washed away from the borehole etc. together with the spring water. Can be reduced as much as possible.

  In addition, when a cement-based consolidated material mixed with glass fiber as described above is used, the front ground of the face 1a is reinforced by the front receiving work A or the mirror reinforcement work B as shown in FIG. 11 (a). The natural ground behavior (extrusion behavior) in which the natural ground 1 in the broken line region 1s of the figure is pushed out to the face 1a side can be suppressed well, and the next tunnel excavation region is excavated as shown in FIG. Even after this, the state in which the reinforcing pipe 6 is fixed and the front ground of the face due to the binder is reinforced can be maintained well, and the axial rigidity and shear rigidity of the reinforcing pipe 6 can be effectively exhibited.

  Further, FIG. 3 shows the time-curing characteristics showing the relationship between time and strength when various kinds of consolidated materials are injected into the reinforcing tube as described above. A in the figure is a conventional standard consolidated material, B Represents a caking material with an emphasis on the development of initial strength such as urethane and super early strength cement, and C represents the characteristics of an caulking material with emphasis on initial handling such as cement. And D in the figure is an ideal time-hardening characteristic from the injection of the consolidated material into the reinforcing pipe until the next tunnel excavation disclosure time, and the cement-based consolidated material mixed with the glass fiber as described above is used. Thus, the above-mentioned ideal time-hardening characteristics can be brought close to.

  In the above embodiment, a GFRP tube having a length of 13.5 m is used as the reinforcing tube 6. However, the reinforcing tube 6 may be formed by sequentially adding shorter tubes with a coupler or the like. In addition, a GFRP tube is more preferable from the viewpoint of compatibility with glass fibers mixed in the cement-based consolidated material (for example, adhesion increases when entangled). However, even when a steel tube is used, adhesion by the glass fibers is also preferable. Can be increased.

  The reinforcing tube 6 is not necessarily limited to a tubular shape having a circular cross section, and may be formed into a tubular shape by combining flat bars, for example. 4 and 5 show an example. In this example, a plurality of flat bars 61 (three in the figure) made of GFRP having a width of 40 mm and a thickness of 6 mm are combined to form a polygonal cross section (in the case of the figure). Is formed in a cylindrical shape with a length of 12 m in the present embodiment, and is formed from the face 1a toward the front ground as in the previous embodiment. It is inserted and arranged in the hole h.

  The plurality of flat bars 61 are arranged around a holding member 62 having a polygonal shape (triangular shape in the figure) as shown in FIGS. 5A and 5B, and a binding member such as a string or a band. 63 is held in a cylindrical shape. A through hole 62a is formed in the central portion of the holding member 62. The injection tube 10 shown in FIG. 5C is inserted into the through hole 62a, and the reinforcing tube 6 made of the flat bar 61 is formed from the injection tube 10. The caking material is injected into the inside of the reinforcing pipe 6 so that the caking material injected into the reinforcing pipe 6 penetrates into the hole h around the reinforcing pipe and into the surrounding natural ground. A gap S through which the consolidated material can flow is formed between the flat bars 61 and 61.

  Further, a packer 11 for forming a bulkhead and a packer injection tube 11a for inflating the packer are loaded at the rear end portion of the reinforcing tube 6 made of the flat bar 61. The packer injection tube 11a extends from the packer injection tube 11a. 11 is injected with urethane having high permeability to form a bulkhead, and then a cement-based solidified material mixed with glass fibers similar to the above-described embodiment is injected into the reinforcing tube 6 made of the flat bar 61. Thus, the mirror reinforcement B is constructed by forming the consolidated region 8. It is also possible to construct the receiver A with the same configuration as described above, and the same effect as described above can be obtained in the receiver A and the mirror reinforcement B.

  In each of the above embodiments, the bulkhead region and the bulkhead are formed on the rear end side of the reinforcing tube 6. However, in this case, the porous tube 6a as described above is omitted. The total length of the reinforcing pipe may be formed by sequentially connecting a single pipe or a plurality of pipes made of a synthetic resin pipe such as a GFRP pipe, a steel pipe, the flat bar reinforcing pipe, or the like.

  In order to investigate the characteristics of the consolidated material used in the present invention as a test example in place of a specific example of the present invention, the following test was performed. First, in a container 30 as shown in FIG. 6 (a), glass fiber having a fiber length of 3 mm is added to dry mortar as a cement-based consolidated material, and 0, 0.7, 1.0, 1 with respect to the weight of the dry mortar, respectively. The amount of water (W / C) with respect to the dry mortar as the cement-based solidified material is 60 to the solidified material added at a ratio of 0.4, 1.7, 2.0, 2.5, and 3.0% by weight Water was added so that it might become weight%, and it stirred with the stirrer 31 as shown in FIG.6 (b), knead | mixed, and produced the kneaded amount mortar of 6.5 liters.

  Next, each kneaded mortar is filled into a steel cylinder 32 having an outer diameter of 114.3 mm × height of 200 mm as shown in FIG. 6C, and the steel cylinder 32 is 40 mm wide × 6 mm thick. A test piece 33 made of a standard flat bar was inserted, and each kneaded mortar was solidified and fixed to prepare a test body 34 as shown in FIG. In the figure, 33a is a stopper for restricting the insertion depth of the specimen 32 into the steel cylinder 31, 35 is a bottom plate integrally fixed to the lower surface side of the steel cylinder 31 by welding, etc. This is a support rod that is integrally fixed to the center of the lower surface of the bottom plate 35 by welding or the like.

  A test of adhesion (pull-out strength) is performed using each of the test specimens 34 produced by varying the amount of glass fiber added to the cement-based consolidated material as described above, and the preparation of each test specimen 34 is performed. A uniaxial compressive strength test of each consolidated material that was sometimes collected was performed. The results are summarized in Table 1 below. The flow values in the following Table 1 are measured values in a P funnel test based on JIS standards, and the uniaxial compressive strength is a cylindrical mold (cylinder provided) having a diameter of 5 cm and a height of 10 cm using each of the above-mentioned binders. Compressive strength (withstand load) when compressed from one end in the axial direction 24 hours after the sample was prepared. Further, the adhesion force is obtained by measuring the pulling load when the upper part of the test piece 32 of each test body 34 and the support rod 36 are held by the clamps of the tester and pulled in the opposite directions. .

  From the data in Table 1 above, the graph in FIG. 7 shows the adhesion force with respect to the glass fiber addition amount, and the graph in FIG. 8 shows the adhesion ratio (adhesion force / compression strength) with respect to the glass fiber addition amount. It is. 7 and 8 indicate the distribution state of the actual measurement values, and the curve is an average value curve of the measurement values for each addition amount.

  From the above test results, the adhesion of each consolidated material shows an increasing tendency when the glass fiber addition amount is 1.0 to 2.0% by weight, and particularly shows a peak when it is 1.7% by weight. Yes. In addition, in the concept of a normal consolidated material, the adhesive force increases as the compressive strength increases. However, according to the test results using this example, the ratio of the adhesive force to the compressive strength is 1 for the glass fiber addition amount. It was found that when the amount was from 0.0 to 2.0% by weight, an increasing tendency was exhibited, and in particular, when the amount was 1.7%, a peak was exhibited. Accordingly, the greater the amount of glass fiber added, the more the adhesion does not increase, but the glass fiber is in a proportion of 1.0 to 2.0% by weight with respect to the weight of dry mortar which is a cement-based consolidated material. When added, the adhesive force can be increased without being excessively cured, and the effect of fixing the ground of the reinforcing pipe as the reinforcing material can be efficiently enhanced.

  As a result of performing various tests other than the above, it has been confirmed that when at least 0.5% by weight or more of glass fiber is added to the cement-based consolidated material, the flow value is increased as compared with the case where it is not added. . In addition, the flow value tends to increase as the amount of glass fiber added increases, which decreases the fluidity of the consolidated material and makes it difficult for leaks to occur, but if it is too much, handling becomes difficult. Since the material cost increases and it is uneconomical, the amount of glass fiber added is preferably 5% by weight or less. Further, as described above, when glass fibers are added in a proportion of 1.0 to 2.0% by weight in the cement-based consolidated material, the adhesion is increased, and in particular, it is mixed in a proportion of 1.7 to 2.0% by weight. GFRP reinforcing material made of cement-based consolidated material (for example, the GFRP pipe used in the embodiment of FIGS. 1 and 2 and the reinforcing pipe formed of a flat bar made of GFRP used in the embodiment of FIGS. 1 and 2). It has been confirmed that the adhesive force is improved by about 19 to 55% compared to the case where glass fiber is not mixed.

  As described above, according to the natural ground reinforcing method according to the present invention, the cement pipe-mixed material mixed with glass fiber is used as a solidifying material for fixing the reinforcing pipe as a reinforcing material and the surrounding natural ground. By using the glass fiber in the above-mentioned consolidated material, the rigidity and adhesion resistance of the consolidated material are ensured by condensing and curing the glass fiber or the glass fiber and the reinforcing tube or ground mountain while being entangled with each other. You can increase your power. In particular, if the glass fiber having a length of 2 to 10 mm is mixed in the cement-based consolidated material in a proportion of 0.5 to 5% by weight, more preferably 1.0 to 2.0% by weight, the reinforcement Even when there are voids such as opening cracks in the hole wall of the drilling hole that accommodates and arranges the pipe, they can be blocked well, suppressing the outflow and escape of cement-based consolidated material, and Before setting and hardening, it can be solidified with little influence from spring water to improve its fixability and reinforcement performance. Therefore, it can be effectively used not only for tunnel leading construction and mirror reinforcement work but also for various industrial ground reinforcement works.

(A) is the longitudinal cross-sectional view of the tunnel of one Embodiment which applied the natural ground reinforcement construction method by this invention to tunnel tip receiving work and mirror reinforcement work, (b) is the cross-sectional view. The expanded vertical cross section of a part of the said embodiment. The graph which shows the time-hardening characteristic of various consolidated materials. The longitudinal cross-sectional view of the tunnel of other embodiment which applied the natural ground reinforcement construction method by this invention to the mirror reinforcement construction. (A) is a perspective view of the reinforcement pipe | tube which consists of a flat bar used for the said embodiment, (b) is a perspective view of the holding member holding a flat bar tubular, (c) is a perspective view of an injection tube. (A)-(d) is explanatory drawing which shows the formation process of the test body for evaluation of a consolidated material. The graph which shows the relationship between the glass fiber addition amount and adhesive force to a cement-type solidification material. The graph which shows the adhesive force ratio with respect to the addition amount of the glass fiber to a cement-type solidification material. (A) is the longitudinal cross-sectional view of the tunnel which shows an example of the conventional prior receiving work, (b) is the cross-sectional view, (c) is a partial enlarged vertical cross-sectional view. (A) is the longitudinal cross-sectional view of the tunnel which shows an example of the conventional mirror reinforcement work, (b) is the cross-sectional view, (c) is a partial enlarged vertical cross-sectional view. (A), (b) is explanatory drawing which shows the natural ground behavior of a tunnel face part.

Explanation of symbols

A Preliminary work B Mirror reinforcement work
T tunnel excavation space h drilling hole 1 ground mountain 1a face 2 mirror part spraying concrete 3 drilling rod 4a spraying concrete 4b steel support 5 rock drill 6 reinforcement pipe 6a perforated pipe 7 bulkhead area 8 consolidation area 9 drill jumbo 9a Guide shell 10 Injection pipe 11 Packer 11a Packer injection pipe 12 Exhaust pipe

Claims (1)

Reinforcing pipe formed by drilling a hole at a predetermined elevation from the tunnel excavation space into the ground in front of the face at the same time, and simultaneously connecting a single pipe or a plurality of pipes having a discharge hole for consolidated material on the peripheral wall In the natural ground reinforcement method of reinforcing and forming a fixed or consolidated region in the reinforcing pipe and surrounding ground in the reinforcing pipe by injecting into the drilling hole, injecting a caking material into the reinforcing pipe,
As the above-mentioned solidification material, a cement-type solidification material such as cement milk or cement mortar mixed with glass fiber is used . A natural ground reinforcement method characterized by using a glass fiber reinforced resin pipe as a single pipe or a plurality of pipes mixed at a rate of 0 to 2.0 % by weight and forming the entire length of the reinforcing pipe.

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