JP4646704B2 - Ground reinforcement method and bit for forming a pilot hole used therefor - Google Patents

Ground reinforcement method and bit for forming a pilot hole used therefor Download PDF

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JP4646704B2
JP4646704B2 JP2005161426A JP2005161426A JP4646704B2 JP 4646704 B2 JP4646704 B2 JP 4646704B2 JP 2005161426 A JP2005161426 A JP 2005161426A JP 2005161426 A JP2005161426 A JP 2005161426A JP 4646704 B2 JP4646704 B2 JP 4646704B2
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reinforcing
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JP2006336282A (en
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淳 石原
正二 鮎澤
優平 鎌田
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株式会社ケー・エフ・シー
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本発明は、例えばトンネル掘削時に切羽前方地山を補強するいわゆる先受け工や鏡部補強工などの地山補強工法、特に地山内に二重管削孔方式等により打設した補強管を介して該補強管内およびその周囲の地山内に固結材を充填して地山を補強する地山補強工法およびそれに用いる下孔形成用ビットに関する。   The present invention is, for example, through a ground reinforcement method such as a so-called receiving construction or mirror reinforcement work for reinforcing the ground in front of the face during tunnel excavation, in particular, through a reinforcement pipe placed in the ground by a double pipe drilling method or the like. In particular, the present invention relates to a natural ground reinforcing method for reinforcing a natural ground by filling a solidified material in the reinforcing pipe and the surrounding natural ground, and a pilot hole forming bit used therefor.
従来、例えば図8および図9に示すようなトンネルTの掘削時に切羽fの前方地山Gを補強する先受け工Aや鏡部補強工Bなどの地山補強工法において、いわゆる二重管削孔方式等により削孔と同時に該削孔内に周面に多数の貫通小穴を有する補強管を打設し、その補強管を介してその周囲の地山内に固結材gを充填して地山を補強するものは知られている(下記特許文献1参照)。   Conventionally, for example, a double pipe cutting in a ground reinforcement method such as a leading construction A or a mirror part reinforcement construction B for reinforcing the front ground G of the face f when excavating the tunnel T as shown in FIGS. At the same time as drilling, a reinforcing pipe having a large number of through holes in the peripheral surface is placed in the drilling hole, etc., and a solid material g is filled in the surrounding natural ground through the reinforcing pipe. What reinforces a mountain is known (see Patent Document 1 below).
図10は上記のような地山補強工法において補強管を打設するまでの具体的なプロセスの一例を示すもので、先ず、同図(a)のように補強管を打設すべき切羽fの所定位置から前方地山Gに向かって補強管よりも大径の下孔hを深さ約300mm程度穿孔する。次いで、その下孔hから二重管削孔方式等により削孔Hを施すと同時に該削孔内に補強管を打設するもので、図の場合は同図(b)のように周面に多数の貫通小穴1aを有する補強管1の先端にケーシングシュー2等を介して削孔ビット3を回転可能に設けると共に、上記補強管1内に挿入した削孔ロッド4の先端部をビットアダプタ5を介して上記削孔ビット3に係合させた状態で、上記削孔ロッド4とともに削孔ビット3を回転させる。   FIG. 10 shows an example of a specific process up to placing a reinforcement pipe in the above-described ground reinforcement method. First, as shown in FIG. A pilot hole h having a diameter larger than that of the reinforcing pipe is drilled from the predetermined position toward the front ground mountain G by a depth of about 300 mm. Next, a drilling hole H is formed from the lower hole h by a double pipe drilling method or the like, and at the same time, a reinforcing pipe is driven into the drilling hole. In the case of the figure, as shown in FIG. A drill bit 3 is rotatably provided at the tip of a reinforcing tube 1 having a large number of through holes 1a through a casing shoe 2 and the like, and the tip of the drill rod 4 inserted into the reinforcing tube 1 is connected to a bit adapter. In a state of being engaged with the drill bit 3 via 5, the drill bit 3 is rotated together with the drill rod 4.
それによって、上記地山G内に削孔Hを施すと同時に該削孔H内に補強管1を打設して行くもので、その際、上記削孔ロッド4と補強管1とは、通常それぞれ所定の長さに形成したものをカプラ等で順次継ぎ足していく。そして所定深さまで削孔し、かつ該削孔H内に所定長さの補強管1を引き込んで打設したところで、上記削孔ロッド4およびビットアダプタ5は引き抜き回収し、補強管1と削孔ビット3は削孔H内に残留させる。   As a result, the hole H is formed in the ground G, and at the same time, the reinforcing tube 1 is driven into the hole H. At that time, the hole 4 and the reinforcing tube 1 are usually Each formed to a predetermined length is successively added with a coupler or the like. When the hole is drilled to a predetermined depth and the reinforcing tube 1 having a predetermined length is drawn into the hole H and driven, the drilling rod 4 and the bit adapter 5 are pulled out and collected. The bit 3 is left in the hole H.
次いで、上記補強管1内の空間を利用して該補強管内およびその周面の地山内に固結材を注入して充填するもので、その注入方式としては、例えば図11(a)に示すようなステップ注入方式と、同図(b)に示すような同時注入方式等がある。即ち、図11(a)は補強管1内をパッカー6等により複数個に室に仕切って、その各室に注入ホース7等を介して固結材を順にステップ注入するもので、特に図の場合は上記パッカー6にパッカー注入ホース9から薬液を注入することによって、上記パッカー6の長手方向両端を膨らませて補強管1の内面に密着させると共に、上記パッカー6の真ん中から薬液を補強管1の外側にもある程度吐出させて補強管1内外に仕切りを形成した後、上記注入ホース7から固結材を注入することによって、上記パッカー6によって仕切られた複数個の室ごとに補強管1内およびその周囲の地山内に固結材を注入充填する構成である。図中、10は排気ホースである。   Next, the space inside the reinforcing pipe 1 is used to inject and fill the solidified material into the reinforcing pipe and the surrounding natural ground. As the injection method, for example, as shown in FIG. Such a step injection method and a simultaneous injection method as shown in FIG. That is, FIG. 11 (a) divides the inside of the reinforcing tube 1 into a plurality of chambers by a packer 6 or the like, and sequentially injects the consolidated material into each chamber via an injection hose 7 or the like. In this case, by injecting a chemical solution into the packer 6 from the packer injection hose 9, both ends in the longitudinal direction of the packer 6 are inflated to adhere to the inner surface of the reinforcing tube 1, and the chemical solution is supplied from the middle of the packer 6 to the reinforcing tube 1. After a partition is formed inside and outside the reinforcing tube 1 by discharging to some extent outside, the inside of the reinforcing tube 1 and the plurality of chambers partitioned by the packer 6 are injected by injecting a caking material from the injection hose 7. It is the structure which inject | pours and fills the consolidated material in the surrounding natural ground. In the figure, 10 is an exhaust hose.
また図11(b)は補強管1内に長さの異なる複数本の注入ホース11a〜11cを設け、その各注入ホース11a〜11cから上記補強管1内に同時に固結材を注入して該補強管内およびその周囲の地山内に固結材を充填するようにしたもので、特に図の場合は各注入ホース11a〜11cの出口側の端部にスタティックミキサ12を設けると共に、補強管1内のほぼ全長にわたって設けた多孔インサート管13を介して補強管1内にウレタン系の固結材を注入する構成である。   FIG. 11 (b) also shows a plurality of injection hoses 11a to 11c having different lengths in the reinforcing tube 1, and simultaneously injecting the caking material into the reinforcing tube 1 from the injection hoses 11a to 11c. In the reinforcing pipe and the surrounding natural ground, a solidification material is filled. Particularly, in the case of the figure, a static mixer 12 is provided at the outlet side end of each of the injection hoses 11a to 11c, and the inside of the reinforcing pipe 1 The urethane-based consolidated material is injected into the reinforcing tube 1 through the porous insert tube 13 provided over almost the entire length.
ところで、上記のような地山補強工法において固結材の注入時に問題となるのは、補強管1の口元側、すなわち削孔Hの開口側のシールが不完全であると、固結材が切羽側へ流出(リーク)してしまうことである。そこで、上記図11(a)および(b)においては補強管1の端部は、同図(a)においてはキャップ14で、同図(b)においては管内コーキング材15でそれぞれ閉塞し、削孔Hの開口側端部のシール手段としては同図(a)および(b)のいずれも下孔hと補強管1との間に口元コーキング材16を充填して閉塞している。   By the way, the problem in the injection of the binder in the above-described ground reinforcement method is that if the seal on the mouth side of the reinforcing pipe 1, that is, the opening side of the drilled hole H is incomplete, the binder is It will flow out (leak) to the face side. Therefore, in FIGS. 11 (a) and 11 (b), the end of the reinforcing pipe 1 is closed by the cap 14 in FIG. 11 (a) and the caulking material 15 in the pipe in FIG. As a sealing means for the opening side end portion of the hole H, the mouth caulking material 16 is filled between the lower hole h and the reinforcing pipe 1 and is closed.
また下記特許文献2においては、上記の問題を解消するために、補強管の口元部位の所定長分を多孔管で構成しておき、先ず、そこから固結材を積極的に漏出させることによって口元部位の周囲の地山内に隔壁となるバルクヘッドを形成し、その後、孔奥側の注入を行うようにした工法が提案されている。   Moreover, in the following Patent Document 2, in order to solve the above-mentioned problem, a predetermined length of the mouth portion of the reinforcing tube is configured with a porous tube, and first, by causing the consolidated material to actively leak from there. There has been proposed a method in which a bulkhead serving as a partition wall is formed in a natural ground around the mouth portion, and thereafter, injection is performed on the back side of the hole.
しかし、上記いずれの場合にも、補強管をトンネル切羽周縁部や鏡面から前方または斜め前方に打設する場合には、前記図8および図12(a)に示すようにドリルジャンボJのガイドセルJ1に補強管1を支持させて、水平方向あるいは斜め上方に向けて削孔Hを施すと同時に該削孔内への補強管1の打設を行うことになる。そのため、どうしても図12(b)および(c)のように下孔の下端位置に補強管の下端位置が合うような方向で下孔の芯と補強管の芯とがずれて削孔および補強管の打設がなされてしまう。   However, in any of the above cases, when the reinforcing pipe is driven forward or obliquely forward from the peripheral edge of the tunnel face or the mirror surface, the guide cell of the drill jumbo J as shown in FIG. 8 and FIG. The reinforcing pipe 1 is supported by J1, and the hole H is formed in the horizontal direction or obliquely upward, and at the same time, the reinforcing pipe 1 is placed in the hole. Therefore, as shown in FIGS. 12B and 12C, the core of the lower hole and the core of the reinforcing pipe are displaced in such a direction that the lower end position of the reinforcing pipe is aligned with the lower end position of the lower hole, so that the drilling hole and the reinforcing pipe Will be made.
例えば前記図8および図12(a)のような先受け工Aにおいて、斜め方向に削孔して補強管を打設する場合には、建て込み済の支保工sをガイドにして、削孔の位置決めをするが、それでも、上記のような補強管1は、その径が100mm前後で長さ3m程度のものをスリーブ状のカプラ17等で何本か接続して延長していくため、つまり、径に対してかなり長尺の管の先端で芯合わせをするため、どうしても、補強管がその自重によって下孔の下部内周面側にずれ落ちた状態で打設されてしまう。   For example, in the first receiving work A as shown in FIG. 8 and FIG. 12 (a), in the case where a reinforcing pipe is placed by drilling in an oblique direction, the built support work s is used as a guide to drill the hole. However, the reinforcing tube 1 as described above is extended by connecting several pipes having a diameter of about 100 mm and a length of about 3 m with a sleeve-like coupler 17 or the like. Since the center of the tube is aligned at the tip of the tube that is considerably long with respect to the diameter, the reinforcing tube is inevitably driven in a state where it is displaced to the lower inner peripheral surface side of the lower hole by its own weight.
その結果、図12(b)および(c)に示すように補強管が下孔の下側に片寄ってしまい補強管の周りにコーキング材等のシール材を詰めることが困難もしくは不可能となる。一方、補強管の上側は、下孔との間が広く開くので、シール材が詰め易いが、多量に詰めなければならない。そのため、シール作業が煩雑かつ面倒で、しかも必ずしも充分にシールできなので、例えば特許文献1においては補強管と削孔との間に流入した固結材がリークするおそれがあり、特許文献2においてはバルクヘット形成用の固結材がリークするおそれがある。   As a result, as shown in FIGS. 12B and 12C, the reinforcing pipe is shifted to the lower side of the lower hole, and it becomes difficult or impossible to pack a sealing material such as a caulking material around the reinforcing pipe. On the other hand, since the upper side of the reinforcing tube is wide open from the lower hole, it is easy to pack the sealing material, but it must be packed in a large amount. Therefore, the sealing work is complicated and troublesome, and it is not always possible to sufficiently seal. For example, in Patent Document 1, there is a risk that the consolidated material that has flowed in between the reinforcing tube and the drilling hole may leak. There is a risk of leakage of the caking material for forming the bulk head.
特開2000−34882号公報JP 2000-34882 A 特開2001−329779号公報JP 2001-329779 A
本発明は上記の問題点に鑑みて提案されたもので、地山内に二重管削孔方式等によって打設した補強管を介して該補強管内およびその周囲の地山内に固結材を充填して地山を補強する際に、上記固結材のリークを防止して地山を簡単・確実に補強することのできる地山補強工法およびそれに適する下孔形成用ビットを提供することを目的とする。   The present invention has been proposed in view of the above-described problems, and a solidified material is filled in the reinforcing pipe and the surrounding natural ground through a reinforcing pipe placed in the natural ground by a double pipe drilling method or the like. An object of the present invention is to provide a natural ground reinforcement construction method capable of easily and surely reinforcing a natural ground by preventing leakage of the above-mentioned consolidated material when reinforcing the natural ground and a bit for forming a pilot hole suitable therefor And
上記の目的を達成するために本発明による地山補強工法およびそれに用いる下孔形成用ビットは、以下の構成としたものである。すなわち、本発明による地山補強工法は、補強管を打設するための削孔径と略同等の径を有する第1穿孔部と、その第1穿孔部よりも大径で、それと同心状の第2穿孔部とを有する段付き下孔を地山に形成した後、上記第1穿孔部を延長するようにして該第1穿孔部と略同径の削孔を施すと同時に該削孔内に補強管を打設し、その補強管の後端部外周と上記第2穿孔部の内面との間に水と反応して膨らむ水膨張性粉体を中空筒状の伸縮性袋体内に収容したパッカーからなるシール手段を介在させた後、上記補強管を介して該補強管内およびその周囲の地山内に固結材を充填して地山を補強する地山補強工法であって、前記パッカーを前記補強管よりも大径のガイド筒体外周面に嵌めた状態で、前記補強管の下孔側の端部と前記第2穿孔部の内面との間に挿入したのち前記ガイド筒体を引き抜き除去することを特徴とする。また本発明による下孔形成用ビットは、上記のような地山補強工法に用いる下孔形成用ビットであって、上記第1穿孔部を形成するための第1ビット部と、上記第2穿孔部を形成するための第2ビット部とを連続的かつ同心状に一体に設けたことを特徴とする。 In order to achieve the above object, the ground reinforcement method according to the present invention and the bit for forming a pilot hole used therefor have the following configurations. That is, the ground reinforcement method according to the present invention includes a first perforated portion having a diameter substantially equal to a diameter of a drilling hole for placing a reinforcing pipe, a diameter larger than the first perforated portion, and a concentric first. After forming a stepped pilot hole having two perforated portions in the ground, the first perforated portion is extended so that a hole having substantially the same diameter as that of the first perforated portion is formed, and at the same time in the bore A reinforcing tube was placed, and a water-expandable powder that expands by reacting with water between the outer periphery of the rear end portion of the reinforcing tube and the inner surface of the second perforated portion was accommodated in a hollow cylindrical elastic bag. after interposing a sealing means comprising a packer, a natural ground reinforcing construction method to reinforce the natural ground by filling a reinforcing tube and consolidating material to the land Yamauchi therearound through the reinforcing tube, the packer In the state where it is fitted to the outer peripheral surface of the guide cylinder having a diameter larger than that of the reinforcing pipe, the end of the reinforcing pipe on the lower hole side and the inside of the second perforated part And removing pulling the guide cylinder body After insertion between. Further, the pilot hole forming bit according to the present invention is a pilot hole forming bit used in the above-described ground reinforcement method, and includes a first bit part for forming the first perforated part, and the second perforated part. The second bit portion for forming the portion is integrally and continuously provided concentrically.
上記のように下孔形成時に、通常の下孔(第2穿孔部)に連続させて、打設する補強管の径に対応した第1穿孔部を形成しておく、その際、下孔形成用ビットとして前記のような、段付きビットを使用すると、段付き下孔を1回の工程で効率よく形成することができる。また上記のようにして形成した第1穿孔部に補強管を挿し込む形で、二重管削孔および補強管の打設作業を行うことにより、下孔の芯と補強管の芯を合わせた形で正確に打設することができる。又それによって、下孔の第2穿孔部におけるシール手段を介在すべき領域を補強管の周囲に正確に環状に形成することができる。その結果、口元部位における補強管周囲のシール作業を簡単かつ確実なものにすることができ、シール作業に手間どらない。またそれによって、固結材の口元部位から切羽側へのリークを確実に阻止することができる。   As described above, when the prepared hole is formed, the first prepared hole corresponding to the diameter of the reinforcing pipe to be placed is formed continuously with the normal prepared hole (second formed hole). When the stepped bit as described above is used as the working bit, the stepped pilot hole can be efficiently formed in one step. Moreover, the core of the lower hole and the core of the reinforcing tube were aligned by performing the double tube drilling hole and the reinforcing tube by inserting the reinforcing tube into the first perforated part formed as described above. Can be placed accurately in the form. In addition, the region where the sealing means in the second perforated portion of the prepared hole is to be interposed can be accurately formed in an annular shape around the reinforcing tube. As a result, the sealing work around the reinforcing pipe at the mouth portion can be made simple and reliable, and the sealing work is not troublesome. Further, it is possible to reliably prevent leakage from the mouth portion of the consolidated material to the face side.
以下、本発明による地山補強工法を、図に示す実施形態に基づいて具体的に説明する。図1および図2は本発明による地山補強工法の一実施形態を示すプロセス説明図であり、先ず、図1(a)に示すように補強すべき地山Gに下孔形成用ビットbで下孔hを形成する。その下孔形成用ビットbには、図示例においては図1(a)および図3に示すように第1穿孔部h1を形成する第1ビット部b1と、その第1穿孔部h1よりも大径でそれと同心状の第2穿孔部h2を形成する第2ビット部b2とが設けられている。   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 and FIG. 2 are process explanatory views showing an embodiment of a natural ground reinforcing method according to the present invention. First, as shown in FIG. A pilot hole h is formed. In the prepared hole forming bit b, in the illustrated example, as shown in FIGS. 1 (a) and 3, a first bit portion b1 for forming a first perforated portion h1 and a larger size than the first perforated portion h1. A second bit part b2 is provided which forms a second perforated part h2 which is concentric with the diameter.
上記第1穿孔部h1およびそれを形成する第1ビット部b1の径d1は、後述する補強管1の径Dと略同等もしくはそれよりもやや大径に形成され、その補強管1を打設するための削孔Hの径と略同等に形成されている。図中、b3は上記第1ビット部b1に先行してそれよりも小径のガイド孔h3を穿孔するためのガイドビット、b0は上記ビットbの取付基部であり、その取付基部b0に図1(a)に示すような穿孔用ロッド18等を継手18a等で連結し、上記穿孔用ロッド18を所定の速度で回転させることによって第1穿孔部h1と第2穿孔部h2とを有する下孔hを形成するものである。   The diameter d1 of the first perforated part h1 and the first bit part b1 that forms the first perforated part h1 is formed to be substantially the same as or slightly larger than the diameter D of the reinforcing pipe 1 described later, and the reinforcing pipe 1 is driven. The diameter of the drilling hole H is approximately the same. In the drawing, b3 is a guide bit for drilling a guide hole h3 having a smaller diameter prior to the first bit portion b1, and b0 is an attachment base portion of the bit b. As shown in a), a drilling rod 18 or the like is connected by a joint 18a or the like, and the drilling rod 18 is rotated at a predetermined speed to prepare a pilot hole h having a first drilling portion h1 and a second punching portion h2. Is formed.
上記のようにして同心状の第1穿孔部h1と第2穿孔部h2とを有する下孔hを形成した後は、図1(b)に示すように上記第1穿孔部h1を延長するようにして削孔ビット3等により同図(c)のように第1穿孔部h1と略同径の削孔Hを施すもので、それによって上記削孔Hを上記第1穿孔部h1および第2穿孔部h2と同心状に精度よく形成することができる。   After the pilot hole h having the concentric first perforated part h1 and the second perforated part h2 is formed as described above, the first perforated part h1 is extended as shown in FIG. Then, a drilling hole H having substantially the same diameter as the first drilled portion h1 is formed by the drilling bit 3 or the like as shown in FIG. 5C, whereby the drilled hole H is formed into the first drilled portion h1 and the second drilled portion h1. It can be accurately formed concentrically with the perforated part h2.
なお上記削孔ビット3は、本実施形態においては前記従来例と同様に補強管1の先端部にケーシングシュー2を介して回転自由に設けられ、補強管1内に挿入した削孔ロッド4によりビットアダプタ5を介して回転させる構成である。その削孔ビット3による必要に応じて打撃を伴う回転動作で削孔Hを施すと同時に、上記削孔ロッド4の削孔内への挿入動作で上記ビットアダプタ5と削孔ビット3およびケーシングシュー2を介して上記補強管1が削孔内に引き込まれる形で打設されていく。   In the present embodiment, the drill bit 3 is rotatably provided at the tip of the reinforcing tube 1 via the casing shoe 2 in the same manner as in the conventional example, and is formed by a drill rod 4 inserted into the reinforcing tube 1. The configuration is such that it is rotated via the bit adapter 5. The hole drilling hole 3 is drilled by a rotating motion accompanied by a hitting as required by the drilling bit 3, and at the same time the bit adapter 5, the drilling bit 3 and the casing shoe are inserted by the operation of inserting the drilling rod 4 into the drilling hole. The reinforcing tube 1 is driven through 2 in such a manner as to be drawn into the drilling hole.
また上記補強管1としては例えば図4に示すように周面に所定のピッチで多数の貫通小穴1aが形成された外径(直径)約100mm程度の鋼管または高強度塩化ビニール管もしくはFRP管などが用いられる。また上記補強管1と削孔ロッド4は、それぞれ必要に応じて順次継ぎ足しながら削孔H内に挿入して行くもので、その場合の継ぎ足し方法は適宜であるが、例えば図4に示すように筒状のカプラ17等を介して継ぎ足す、あるいは接続すべき端部に雌雄のねじ部を形成して互いにねじ込み嵌合させたり、接着剤や溶接を併用することもできる。   As the reinforcing pipe 1, for example, as shown in FIG. 4, a steel pipe having a large number of through holes 1a formed at a predetermined pitch on the peripheral surface (diameter) of about 100 mm, a high-strength vinyl chloride pipe, an FRP pipe, or the like Is used. Further, the reinforcing tube 1 and the drilling rod 4 are inserted into the drilling hole H while being sequentially added as necessary. In this case, the adding method is appropriate. For example, as shown in FIG. It can be added via a cylindrical coupler 17 or the like, or a male and female threaded portion can be formed at the end to be connected and screwed into each other, or an adhesive or welding can be used together.
上記のようにして所定の深さの削孔Hを施すと同時に該削孔H内に所定長さの補強管1を順次図1(d)のように打設したところで、上記削孔ロッド4を逆転する等してビットアダプタ5と削孔ビット3との係合を解除した後、上記削孔ロッド4とともにビットアダプタ5を補強管1内から引き抜き回収し、削孔ビット3と補強管1とは上記削孔H内に残留させる。なお上記補強管1内から引き抜き回収した削孔ロッド4とビットアダプタ5は繰り返し使用することができる。   When the hole H having a predetermined depth is formed as described above, the reinforcing tube 1 having a predetermined length is sequentially placed in the hole H as shown in FIG. The bit adapter 5 and the drilling bit 3 are released from each other by reversing the rotation, and then the bit adapter 5 is pulled out and collected together with the drilling rod 4 from the reinforcing tube 1. Is left in the hole H. The drilling rod 4 and the bit adapter 5 drawn out and collected from the reinforcing tube 1 can be used repeatedly.
なお、上記削孔ビット3等の構成は、上記に限らず適宜変更可能であり、例えば補強管1の先端にリングビット等の使い捨てビットを装着し、削孔ロッド4の先端に上記使い捨てビットに係合するセンタービット等の回収ビットを装着した構成でもよく、あるいは削孔時には補強管1の外径と同等もしくはそれよりも僅かに大きく拡開可能な、いわゆる拡開ビットを削孔ロッドの先端部に装着して削孔時には補強管先端から前方に突出させて削孔しながら補強管を打設し、補強管を打設した後は上記拡開ビットを縮径して引き抜き回収するようにしたものでもよい。   The configuration of the drill bit 3 and the like is not limited to the above, and can be changed as appropriate. For example, a disposable bit such as a ring bit is attached to the tip of the reinforcing tube 1 and the disposable bit is attached to the tip of the drill rod 4. It may have a configuration in which a collecting bit such as an engaging center bit is mounted, or a so-called expanding bit that can be expanded to the same or slightly larger than the outer diameter of the reinforcing tube 1 at the time of drilling. At the time of drilling, the hole is projected forward from the tip of the reinforcing pipe, and the reinforcing pipe is placed while drilling. After the reinforcing pipe is placed, the expanding bit is reduced in diameter and collected. You may have done.
また図示例は削孔ロッド4の削孔H内への挿入動作に連動して補強管を削孔内に引き込む形で打設するようにしたが、例えば削孔ロッド4の挿入動作とは独立に若しくはそれと同時に補強管の後端部を削孔内に押し込む又は叩き込むようにして前記削孔H内に打設してもよい。   In the illustrated example, the reinforcing tube is driven in such a manner that the reinforcing rod is pulled into the drilling hole in conjunction with the insertion operation of the drilling rod 4 into the drilling hole H. However, for example, it is independent of the insertion operation of the drilling rod 4. Alternatively, at the same time, the rear end portion of the reinforcing pipe may be pushed into the drilling hole or may be driven into the drilling hole H.
次に、前記図1(d)のように削孔H内に所定長さの補強管1を打設したところで、該削孔Hの口元部(開口部)を適宜のシール手段20でシールするもので、そのシール手段20として本実施形態においては図2(a)に示すようなドーナツ状のパッカー21を用いるようにしたものである。そのパッカー21は、図の場合は図5〜図7に示すように中空筒状の伸縮性袋体21a内に、水と反応して膨らむ水膨張性粉体22を収容した構成であり、その水膨張性粉体22として本実施形態においてはポリアクリル酸ナトリウム等の吸水性ポリマー22aにセメント22b等の水硬化性の固結材を混合したものが用いられている。図中、23は上記パッカー21内に水を注入するための注水パイプである。   Next, as shown in FIG. 1 (d), when the reinforcing tube 1 having a predetermined length is driven into the hole H, the mouth (opening) of the hole H is sealed with appropriate sealing means 20. In this embodiment, a donut-shaped packer 21 as shown in FIG. 2A is used as the sealing means 20. In the case of the figure, the packer 21 has a structure in which a water-expandable powder 22 that expands by reacting with water is accommodated in a hollow cylindrical elastic bag body 21a as shown in FIGS. In this embodiment, the water-swellable powder 22 is a mixture of a water-absorbing polymer 22a such as sodium polyacrylate and a water-curable solid material such as cement 22b. In the figure, reference numeral 23 denotes a water injection pipe for injecting water into the packer 21.
上記パッカー21は図2(b)に示すように前記第2穿孔部h2と補強管1との間に挿入するもので、その際、例えば図2(a)および図5に示すように補強管1よりも僅かに大径のガイド筒体24の外周面に、上記パッカー21を嵌めた状態で、図2(b)のように補強管1の端部外周に挿入したのち、同図(c)のように上記ガイド筒体24を引き抜き除去すれば補強管1の外周面に上記パッカー21を容易に装着することができる。又この場合、パッカー21の袋体21aを伸縮性を有する材料で形成すると共に、水膨張性粉体を収容した状態における内径を補強管1の外径よりも小さく形成しておけば、上記パッカー21をガイド筒体24や補強管1の外周面に嵌めたとき、上記伸縮性袋体21aの収縮で上記ガイド筒体24や補強管1の外周面に密着保持させることができる。   The packer 21 is inserted between the second perforated part h2 and the reinforcing tube 1 as shown in FIG. 2 (b). In this case, for example, as shown in FIGS. 2 (a) and 5, the reinforcing tube 2 is inserted into the outer periphery of the end of the reinforcing tube 1 as shown in FIG. 2 (b) with the packer 21 fitted on the outer peripheral surface of the guide cylinder 24 having a diameter slightly larger than 1. FIG. If the guide cylinder 24 is pulled out and removed as in (), the packer 21 can be easily mounted on the outer peripheral surface of the reinforcing tube 1. In this case, if the bag body 21a of the packer 21 is formed of a stretchable material and the inner diameter of the packer 21 containing the water-expandable powder is smaller than the outer diameter of the reinforcing tube 1, the packer When 21 is fitted to the outer peripheral surface of the guide cylinder 24 or the reinforcing tube 1, the elastic bag body 21 a can be held in close contact with the outer peripheral surface of the guide cylinder 24 or the reinforcing tube 1.
上記のようにして第2穿孔部h2と補強管1との間の補強管外周面にパッカー21を装着した後は、図2(d)のように注水パイプ23からパッカー21内に水を注入して水膨張性粉体22を膨張させればよく、図示例においては上記パッカー21内に注入された水は、図7に示す水膨張性粉体22の吸水性ポリマー22aに吸収されて該ポリマー22a等が同図(a)の状態から同図(b)のように膨張する。それによって図2(d)のように筒状のパッカー21の内外両面が補強管1の後端部外周面と第2穿孔部h2の内面とに密着して補強管1と下孔hとの隙間が閉塞される。その後、実施形態においては上記吸水性ポリマー22aで吸収された水は、パッカー21内のセメント22bに徐々に吸収されて該セメントの水和反応で次第に硬化し、上記パッカー21が膨張して硬化した状態に保持される。   After mounting the packer 21 on the outer peripheral surface of the reinforcing pipe between the second perforated part h2 and the reinforcing pipe 1 as described above, water is injected into the packer 21 from the water injection pipe 23 as shown in FIG. Then, the water expandable powder 22 may be expanded. In the illustrated example, the water injected into the packer 21 is absorbed by the water absorbent polymer 22a of the water expandable powder 22 shown in FIG. The polymer 22a and the like expand from the state shown in FIG. As a result, as shown in FIG. 2D, both the inner and outer surfaces of the cylindrical packer 21 are brought into close contact with the outer peripheral surface of the rear end portion of the reinforcing tube 1 and the inner surface of the second perforated portion h2, and the reinforcing tube 1 and the lower hole h are formed. The gap is closed. Thereafter, in the embodiment, the water absorbed by the water-absorbing polymer 22a is gradually absorbed by the cement 22b in the packer 21 and gradually hardens by the hydration reaction of the cement, and the packer 21 expands and hardens. Held in a state.
以後は前記従来例と同様に補強管1の口元側の端部を前記図11(a)のようなキャップ14や同図(b)のような管内コーキング材15等で閉塞すると共に、同図(a)のようなステップ注入方式や、同図(b)のような同時注入方式等によって上記補強管1内およびその周囲の地山内に固結材を注入充填して補強すればよい。   Thereafter, as in the conventional example, the end of the reinforcing tube 1 on the mouth side is closed with a cap 14 as shown in FIG. 11 (a), an in-tube caulking material 15 as shown in FIG. 11 (b), and the like. What is necessary is just to reinforce by injecting and filling the solidified material into the reinforcing pipe 1 and the surrounding natural ground by the step injection method as shown in (a), the simultaneous injection method as shown in FIG.
上記のように本発明においては、第1穿孔部h1とそれよりも大径でそれと同心状の第2穿孔部h2とを有する下孔hを形成した後、上記第1穿孔部h1を延長するようにして削孔Hを施すと同時に該削孔H内に補強管1を打設したことによって、該補強管1の後端部外周面と第2穿孔部h2との間には、シール手段を介在すべき領域が正確に環状に形成されるので、ここにシール手段20を簡単・確実に介在させることができる。   As described above, in the present invention, after forming the pilot hole h having the first perforated part h1 and the second perforated part h2 having a diameter larger than that of the first perforated part h1, the first perforated part h1 is extended. In this way, by providing the drilling hole H and simultaneously placing the reinforcing pipe 1 in the drilling hole H, a sealing means is provided between the outer peripheral surface of the rear end portion of the reinforcing pipe 1 and the second perforated part h2. Since the region to be interposed is formed in an accurate ring shape, the sealing means 20 can be interposed easily and reliably here.
特に、シール手段20として上記実施形態のような水膨張性粉体22を収容したドーナツ状のパッカー21を介在させる場合には、補強管1と第2穿孔部h2との間隔に偏りやバラツキがなく正確に環状に形成されるので、装填が容易であり、簡単・確実にシールすることができる。また上記水膨張性粉体22として前記実施形態のように吸水性ポリマー22aとセメント22bとを用いると、吸水性ポリマー22aの吸水時の膨張作用と、その後のセメント22bの水和反応による硬化作用で安定かつより一層確実にシールすることができるものである。   In particular, when the doughnut-shaped packer 21 containing the water-expandable powder 22 as in the above embodiment is interposed as the sealing means 20, there is a deviation or variation in the interval between the reinforcing tube 1 and the second perforated part h2. Since it is formed in an annular shape accurately, it is easy to load and can be easily and reliably sealed. Further, when the water-absorbing polymer 22a and the cement 22b are used as the water-expandable powder 22 as in the above-described embodiment, the water-absorbing polymer 22a expands when it absorbs water, and then hardens due to the hydration reaction of the cement 22b. Thus, it can be stably and more reliably sealed.
なお、上記パッカー21の伸縮性袋体21aを通水性材料で構成すれば、地山内から浸透してきた湧水等で上記パッカー内の吸水性ポリマー22a等の水膨張性粉体22を膨張させながら一次的に湧水を止め、その後セメント22bの硬化によって補強管口元部位を確実にシールすることもできる。   If the stretchable bag 21a of the packer 21 is made of a water-permeable material, the water-expandable powder 22 such as the water-absorbing polymer 22a in the packer is inflated by spring water that has permeated from the ground. The spring water can be temporarily stopped, and then the reinforcing tube mouth portion can be reliably sealed by hardening the cement 22b.
以上のように本発明による地山補強工法およびそれに用いる下孔形成用ビットは上記の構成であるから、例えばトンネル掘削時に切羽前方地山を補強するいわゆる先受け工や鏡部補強工などに良好に適用できると共に、上記以外にも地盤の補強やその他の地山補強工法にも有効に適用することができる。   As described above, the natural ground reinforcement method according to the present invention and the pilot hole forming bit used therefor have the above-described configuration, so that it is suitable for, for example, a so-called front receiving work or mirror part reinforcing work for reinforcing the natural ground in front of the face during tunnel excavation. In addition to the above, it can be effectively applied to ground reinforcement and other ground reinforcement methods.
(a)〜(d)は本発明による地山補強工法の一実施形態を示す補強管打設工程までのプロセス説明図。(A)-(d) is process explanatory drawing to the reinforcement pipe | tube setting process which shows one Embodiment of the natural ground reinforcement construction method by this invention. (a)〜(d)は上記実施形態における口元シール工程のプロセス説明図。(A)-(d) is process explanatory drawing of the mouth sealing process in the said embodiment. 下孔形成用ビットの一例を示す説明図。Explanatory drawing which shows an example of the bit for pilot hole formation. 補強管およびその接続用カプラの一例を示す説明図。Explanatory drawing which shows an example of a reinforcing pipe and its connection coupler. シール部材としてのパッカーの一例を示す縦断面図。The longitudinal cross-sectional view which shows an example of the packer as a sealing member. (a)および(b)は上記パッカーの膨張前および膨張後の斜視図。(A) And (b) is a perspective view of the packer before and after expansion. (a)および(b)は水膨張性粉体の膨張前および膨張後の模式図。(A) And (b) is a schematic diagram of the water-expandable powder before and after expansion. 従来の地山補強工法の一例を示す縦断面図。The longitudinal cross-sectional view which shows an example of the conventional natural ground reinforcement construction method. 上記従来の地山補強工法の横断面図。The cross-sectional view of the conventional natural ground reinforcement method. (a)〜(b)は従来の地山補強工法における補強管打設工程までのプロセス説明図。(A)-(b) is process explanatory drawing to the reinforcement pipe | tube placing process in the conventional natural ground reinforcement construction method. (a)及び(b)は従来の地山補強工法における固結材注入工程の説明図。(A) And (b) is explanatory drawing of the consolidation agent injection | pouring process in the conventional natural ground reinforcement construction method. (a)は従来の地山補強工法における削孔状態の説明図、(b)はその一部の拡大図、(c)はその正面図。(A) is explanatory drawing of the drilling state in the conventional natural ground reinforcement construction method, (b) is the one part enlarged view, (c) is the front view.
符号の説明Explanation of symbols
A 先受け工
B 鏡部補強工
G 地山
H 削孔
f 切羽
g 固結材
h 下孔
1 補強管
2 ケーシングシュー
3 削孔ビット
4 削孔ロッド
5 ビットアダプタ
20 シール手段
21 パッカー
21a 伸縮性袋体
22 水膨張性粉体
22a 吸水性ポリマー
22b セメント
23 注水パイプ
24 ガイド筒体
A Preliminary work B Mirror part reinforcement G Ground mountain H Drilling hole f Face g Solid binder h Pilot hole
DESCRIPTION OF SYMBOLS 1 Reinforcement pipe 2 Casing shoe 3 Drilling bit 4 Drilling rod 5 Bit adapter 20 Sealing means 21 Packer 21a Stretchable bag 22 Water-expandable powder 22a Water-absorbing polymer 22b Cement 23 Injection pipe 24 Guide cylinder

Claims (2)

  1. 補強管を打設するための削孔径と略同等の径を有する第1穿孔部と、その第1穿孔部よりも大径で、それと同心状の第2穿孔部とを有する段付き下孔を地山に形成した後、上記第1穿孔部を延長するようにして該第1穿孔部と略同径の削孔を施すと同時に該削孔内に補強管を打設し、その補強管の後端部外周と上記第2穿孔部の内面との間に水と反応して膨らむ水膨張性粉体を中空筒状の伸縮性袋体内に収容したパッカーからなるシール手段を介在させた後、上記補強管を介して該補強管内およびその周囲の地山内に固結材を充填して地山を補強する地山補強工法であって、
    前記パッカーを前記補強管よりも大径のガイド筒体外周面に嵌めた状態で、前記補強管の下孔側の端部と前記第2穿孔部の内面との間に挿入したのち前記ガイド筒体を引き抜き除去することを特徴とする地山補強工法。
    A stepped pilot hole having a first perforated portion having a diameter substantially equal to a diameter of a drilling hole for placing the reinforcing pipe, and a second perforated portion having a diameter larger than that of the first perforated portion and concentric with the first perforated portion. After forming in the natural ground, the first perforated part is extended so as to extend a hole having substantially the same diameter as the first perforated part, and at the same time, a reinforcing pipe is placed in the drilled hole. After interposing a sealing means consisting of a packer in which a water-expandable powder that expands by reacting with water between the outer periphery of the rear end portion and the inner surface of the second perforated portion is contained in a hollow cylindrical elastic bag body , A natural ground reinforcement method for reinforcing a natural ground by filling a solidified material in the reinforcing pipe and surrounding natural ground via the reinforcing pipe ,
    The guide tube is inserted between the end portion on the lower hole side of the reinforcing tube and the inner surface of the second perforated portion in a state where the packer is fitted to the outer peripheral surface of the guide tube body having a larger diameter than the reinforcing tube. A ground reinforcement method characterized by drawing and removing the body .
  2. 前記伸縮性袋体が、通水性材料からなる請求項に記載の地山補強工法。 The ground reinforcement method according to claim 1 , wherein the stretchable bag body is made of a water-permeable material.
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JP4939260B2 (en) * 2007-03-07 2012-05-23 鹿島建設株式会社 Inserting long members into the ground
JP4938622B2 (en) * 2007-11-01 2012-05-23 鹿島建設株式会社 Filling the filling material into the long pipe
JP5119132B2 (en) * 2008-11-19 2013-01-16 株式会社ケー・エフ・シー Insert unit for ground reinforcement and ground reinforcement method using the same
JP6676517B2 (en) * 2016-12-05 2020-04-08 飛島建設株式会社 Tunnel tarpaulin protection method, drill bit and drill tool used therefor

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JPS6335109Y2 (en) * 1984-08-17 1988-09-19
JP2953968B2 (en) * 1994-10-27 1999-09-27 日特建設株式会社 Enlarged excavation equipment for recess for anchor head storage

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