JP6230861B2 - Ground improvement method by high-pressure jet stirring method - Google Patents

Ground improvement method by high-pressure jet stirring method Download PDF

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JP6230861B2
JP6230861B2 JP2013203905A JP2013203905A JP6230861B2 JP 6230861 B2 JP6230861 B2 JP 6230861B2 JP 2013203905 A JP2013203905 A JP 2013203905A JP 2013203905 A JP2013203905 A JP 2013203905A JP 6230861 B2 JP6230861 B2 JP 6230861B2
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ground
tube rod
cement milk
pressure
underground obstacle
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JP2015068075A (en
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田中　肇一
肇一 田中
磯谷　修二
修二 磯谷
雅則 岡戸
雅則 岡戸
嘉孝 中嶋
嘉孝 中嶋
鈴木　亮彦
亮彦 鈴木
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Fudo Tetra Corp
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Description

本発明は、地盤中に高速高圧で硬化材を噴射し、この噴射エネルギーで地盤を切削しながら噴射した硬化材と地盤とを攪拌混合させ、地盤中に固結改良体を造成して地盤を改良するようにした高圧噴射攪拌工法による地盤改良方法に関し、特に、既設構造物直下における地盤を改良するときの高圧噴射攪拌工法による地盤改良方法に関する。   The present invention sprays a hardened material at high speed and high pressure into the ground, stirs and mixes the hardened material sprayed while cutting the ground with this jet energy, and creates a consolidated improvement body in the ground. More particularly, the present invention relates to a ground improvement method using a high pressure jet stirring method for improving the ground directly under an existing structure.

従来、高圧噴射攪拌工法による地盤改良方法としては、施工機械４１にて地盤中に管ロッド４２を所定深度まで挿入し、挿入後、図１４に示すように、管ロッド４２を回動させて管ロッド４２先端の噴射口４３からセメントミルク等の硬化材を高速高圧で噴射する。そして、この硬化材の噴射エネルギーで地盤を切削しながら噴射した硬化材と地盤とを攪拌混合させ、この管ロッド４２を回動して一回転（３６０度）させ、これを上方に引き抜きながら行うことにより、地盤中に縦向きの円柱状の固結改良体Ｔを造成して地盤を改良するようにしたものが一般的に知られていた。   Conventionally, as a ground improvement method by a high-pressure jet agitation method, a pipe rod 42 is inserted into the ground by a construction machine 41 to a predetermined depth, and after insertion, as shown in FIG. A hardening material such as cement milk is jetted at a high speed and a high pressure from the jet port 43 at the tip of the rod 42. Then, the hardened material and the ground sprayed while cutting the ground with the jetting energy of the hardened material are agitated and mixed, and this tube rod 42 is rotated and rotated once (360 degrees), and this is performed while pulling upward. Thus, it has been generally known that a vertical columnar consolidation improvement body T is formed in the ground to improve the ground.

また、この高圧噴射攪拌工法による地盤改良方法の別の例として、地盤中に縦向きの円柱状の固結改良体Ｔを造成する代わりに、管ロッド４２の回動を一回転（３６０度）させるのではなく、一定の角度の範囲内で管ロッド４２を回動させ、たとえば、管ロッド４２の回動を三分の一回転（１２０度）させることで、扇形の柱状の固結改良体Ｔを造成して地盤を改良するようにしたものもあった。これは、特に、建物などの既製構造物Ｋがある場所の地盤、すなわち既設構造物Ｋ直下における地盤を改良するときに用いられていた。   As another example of the ground improvement method by this high-pressure jet agitation method, the tube rod 42 is rotated once (360 degrees) instead of creating a vertical columnar consolidated improvement body T in the ground. Instead of rotating the tube rod 42 within a certain angle range, for example, by rotating the tube rod 42 by one third (120 degrees), a fan-shaped columnar consolidated improvement body There were some that improved T by creating T. This has been particularly used to improve the ground where there is a ready-made structure K such as a building, that is, the ground directly under the existing structure K.

このような建物などの既製構造物Ｋ直下における地盤を改良するとき、既設構造物Ｋの下の地盤中には基礎杭などの地中障害物Ｐが多数存在することが多々あった。この地中障害物Ｐが既設構造物Ｋの下などの地盤中に存在する場合において、従来の高圧噴射攪拌工法による地盤改良方法によって地盤を改良しようとすると、回動している管ロッド４２から噴射したセメントミルク等の硬化材が地盤中に存在する地中障害物Ｐに当たって遮られてしまうため、図１５に示すように、噴射した硬化材を地中障害物Ｐの背面側に十分に送り込むことができなかった。このため、既設構造物Ｋ直下における地盤を改良するとき、地中障害物Ｐの背面側に固結改良体Ｔを造成できずに未造成箇所Ｓができてしまうため、地盤を良好に改良することができなくなるといった問題が生じるおそれがあった。   When improving the ground directly under an existing structure K such as a building, there are often many underground obstacles P such as foundation piles in the ground under the existing structure K. In the case where the underground obstacle P exists in the ground such as under the existing structure K, if the ground is improved by the conventional ground improvement method using the high-pressure jet stirring method, the rotating tube rod 42 is removed. Since the injected hardened material such as cement milk hits the underground obstacle P existing in the ground and is blocked, the injected hardened material is sufficiently fed to the back side of the underground obstacle P as shown in FIG. I couldn't. For this reason, when improving the ground just under the existing structure K, the solidified improvement body T cannot be formed on the back side of the underground obstacle P, and an undeveloped portion S is formed. There was a risk of problems such as being unable to do so.

そこで、本発明は、このような問題点に鑑み、既設構造物直下における地盤を改良するとき、地中障害物の背面側に十分に硬化材を送り込むことにより、地中障害物の背面側にも固結改良体を造成可能にすることで、地盤中に地中障害物が存在するような場所でも、極めて良好に地盤を改良することのできる高圧噴射攪拌工法による地盤改良方法を提供することを、その課題とする。   Therefore, in view of such problems, the present invention, when improving the ground directly under the existing structure, by sufficiently feeding the curing material to the back side of the underground obstacle, to the back side of the underground obstacle Providing a ground improvement method by high-pressure jet agitation method that can improve the ground very well even in places where there are underground obstacles in the ground by making it possible to build a consolidation improvement body Is the issue.

第一の発明は、施工機械にて地盤中に管ロッドを所定深度まで挿入し、挿入後、管ロッドから硬化材を高速高圧で噴射し、この硬化材の噴射エネルギーで地盤を切削しながら噴射した硬化材と地盤とを攪拌混合させ、地盤中に固結改良体を造成して地盤を改良するようにした高圧噴射攪拌工法による地盤改良方法において、既設構造物の下などの地盤中に地中障害物が存在する場合、この地中障害物の際に向けて、管ロッドを回動させることなく停止した状態で管ロッドから硬化材を高速高圧で直線的に所定時間噴射し、地中障害物の背面側に噴射した硬化材を廻り込ませるようにした高圧噴射攪拌工法による地盤改良方法である。   In the first invention, the tube rod is inserted into the ground with a construction machine to a predetermined depth, and after insertion, the hardened material is injected from the tube rod at high speed and high pressure, and the ground is cut while cutting the ground with the injection energy of this hardened material. In the ground improvement method using the high-pressure jet agitation method, which stirs and mixes the hardened material and the ground and creates a consolidated improvement body in the ground to improve the ground, the ground is placed under the existing structure. When there is a medium obstacle, the hardened material is sprayed straight from the tube rod at a high speed and high pressure for a predetermined time in a state where the tube rod is stopped without rotating toward the underground obstacle. This is a ground improvement method using a high-pressure jet agitation method in which the hardened material sprayed around the back side of the obstacle is circulated.

第二の発明は、第一の発明において、管ロッドを回動させることなく停止した状態で管ロッドから硬化材を高速高圧で直線的に所定時間噴射する際の噴射する時間を、地盤中に存在する地中障害物の大きさに基づいて変更するようにした高圧噴射攪拌工法による地盤改良方法である。   According to a second invention, in the first invention, the time for spraying the hardened material from the tube rod linearly at a high speed and high pressure for a predetermined time in the ground in a state where the tube rod is stopped without rotating. This is a ground improvement method using a high-pressure jet agitation method that is changed based on the size of the existing underground obstacle.

本発明によれば、地盤中に存在する地中障害物の際に向けて、管ロッドを回動させることなく停止した状態で管ロッドから硬化材を高速高圧で直線的に所定時間噴射し、地中障害物の背面側に噴射した硬化材を廻り込ませるようにしたことで、管ロッドから噴射した硬化材を地中障害物の背面側に十分に送り込むことができ、地中障害物の背面側にも固結改良体を造成することにより、地盤中に完璧な固結改良体を造成することができ、これにより、既設構造物直下における地盤を改良するとき、地盤中に存在する地中障害物に邪魔されることなく、極めて良好に地盤を強固な地盤へと改良することができる。   According to the present invention, the hardened material is sprayed linearly at a high speed and high pressure for a predetermined time from the tube rod in a state where it is stopped without rotating the tube rod toward the underground obstacle existing in the ground, By making the hardened material sprayed around the back side of the underground obstacles, the hardened material sprayed from the tube rod can be sufficiently fed to the back side of the underground obstacles, By creating a consolidation improvement body on the back side, it is possible to create a perfect consolidation improvement body in the ground, which makes it possible to improve the ground directly under the existing structure. The ground can be improved to a solid ground very well without being obstructed by middle obstacles.

また、管ロッドを回動させることなく停止した状態で管ロッドから硬化材を高速高圧で直線的に所定時間噴射する際の噴射する時間を、地盤中に存在する地中障害物の大きさに基づいて変更するようにしたことで、地中障害物の大きさに応じて硬化材の噴射する時間をコントロールすることにより、効率の良い作業を行うことができ、作業性の向上を図ることができる。   In addition, the time for spraying the hardened material from the tube rod linearly at a high speed and high pressure for a predetermined time with the tube rod stopped without rotating is set to the size of the underground obstacle existing in the ground. By changing based on the size of the underground obstacle, it is possible to perform efficient work and improve workability by controlling the time for injecting the curing material according to the size of the underground obstacle it can.

本発明における高圧噴射攪拌機の説明図である。It is explanatory drawing of the high pressure injection stirrer in this invention. 本発明における特殊先端具の正面図である。It is a front view of the special tip implement in the present invention. 本発明における特殊先端具を下面図である。It is a bottom view of the special tip tool in the present invention. 本発明における別の特殊先端具の正面図である。It is a front view of another special tip implement in the present invention. 本発明における別の特殊先端具の正面図である。It is a front view of another special tip implement in the present invention. 本発明における別の特殊先端具の正面図である。It is a front view of another special tip implement in the present invention. 既設構造物直下における地盤を改良するときの本発明の高圧噴射攪拌工法による地盤改良方法での状態を説明する上面図である。It is a top view explaining the state in the ground improvement method by the high-pressure jet stirring method of the present invention when improving the ground directly under an existing structure. （ａ）本発明の高圧噴射攪拌工法による地盤改良方法の作業工程の説明図である。（ｂ）本発明の高圧噴射攪拌工法による地盤改良方法の作業工程の説明図である。（ｃ）本発明の高圧噴射攪拌工法による地盤改良方法の作業工程の説明図である。(A) It is explanatory drawing of the operation | work process of the ground improvement method by the high pressure injection stirring method of this invention. (B) It is explanatory drawing of the operation | work process of the ground improvement method by the high pressure jet stirring construction method of this invention. (C) It is explanatory drawing of the operation | work process of the ground improvement method by the high voltage | pressure injection stirring construction method of this invention. 本発明の高圧噴射攪拌工法による地盤改良方法における地盤中に固結改良体を造成した状態の説明図である。It is explanatory drawing of the state which created the consolidation improvement body in the ground in the ground improvement method by the high-pressure jet stirring method of this invention. （ａ）本発明の高圧噴射攪拌工法による地盤改良方法における硬化材を噴射しているときの上面図である。（ｂ）本発明の高圧噴射攪拌工法による地盤改良方法における硬化材を噴射しているときの上面図である。(A) It is a top view when injecting the hardening material in the ground improvement method by the high-pressure jet stirring method of the present invention. (B) It is a top view when injecting the hardening material in the ground improvement method by the high-pressure jet stirring method of the present invention. （ｄ）本発明の高圧噴射攪拌工法による地盤改良方法の作業工程の説明図である。（ｅ）本発明の高圧噴射攪拌工法による地盤改良方法の作業工程の説明図である。（ｆ）本発明の高圧噴射攪拌工法による地盤改良方法の作業工程の説明図である。(D) It is explanatory drawing of the operation | work process of the ground improvement method by the high voltage | pressure injection stirring construction method of this invention. (E) It is explanatory drawing of the work process of the ground improvement method by the high-pressure jet stirring method of this invention. (F) It is explanatory drawing of the operation | work process of the ground improvement method by the high voltage | pressure injection stirring construction method of this invention. 本発明の高圧噴射攪拌工法による地盤改良方法における硬化材の噴射状態を説明する上面図である。It is a top view explaining the injection state of the hardening | curing material in the ground improvement method by the high pressure injection stirring method of this invention. 本発明の高圧噴射攪拌工法による地盤改良方法における地盤中に他の固結改良体を造成した状態の説明図である。It is explanatory drawing of the state which created the other consolidation improvement body in the ground in the ground improvement method by the high-pressure jet stirring method of this invention. 従来の高圧噴射攪拌工法による地盤改良方法の説明図である。It is explanatory drawing of the ground improvement method by the conventional high-pressure jet stirring method. 既設構造物直下における地盤を改良するときの従来の高圧噴射攪拌工法による地盤改良方法での状態を説明する上面図である。It is a top view explaining the state in the ground improvement method by the conventional high-pressure jet stirring method when improving the ground directly under an existing structure.

本発明による高圧噴射攪拌工法による地盤改良方法の実施形態について説明する。
まず、この高圧噴射攪拌工法による地盤改良方法において使用する高圧噴射攪拌機について説明すると、図１に示すように、地盤中に管ロッド２を所定深度まで挿入あるいは引き抜くための施工機械１を備え、この施工機械１はたとえば自走可能な小型の杭打ち機である。ただし、施工機械１としては小型の杭打ち機に限定されるものではなく、地盤改良の施工深度等の改良規模に応じてボーリングマシンや他の機械でも良い。そして、この施工機械１にあっては、マスト３を立設し、このマスト３に沿って管ロッド２を縦に向けて取り付けると共に、マスト３の上部に管ロッド２を地盤中に挿入したり引き抜いたりする昇降装置４と管ロッド２を回動させる回動装置５をそれぞれ設ける。管ロッド２はその内側を硬化材や圧縮空気等が通るようになる中空状の鋼管であり、その下端である先端に特殊先端具６を取り付けている。 An embodiment of the ground improvement method by the high-pressure jet stirring method according to the present invention will be described.
First, a high-pressure jet agitator used in the ground improvement method by this high-pressure jet agitation method will be described. As shown in FIG. 1, a construction machine 1 for inserting or extracting a tube rod 2 to a predetermined depth is provided in the ground. The construction machine 1 is, for example, a small pile driver capable of self-propelling. However, the construction machine 1 is not limited to a small pile driving machine, and may be a boring machine or other machines depending on the scale of improvement such as the depth of construction for ground improvement. In this construction machine 1, the mast 3 is erected and the tube rod 2 is attached vertically along the mast 3, and the tube rod 2 is inserted into the ground above the mast 3. A lifting device 4 for pulling out and a rotating device 5 for rotating the tube rod 2 are provided. The tube rod 2 is a hollow steel tube through which hardened material, compressed air, etc. pass, and a special tip 6 is attached to the tip which is the lower end thereof.

また、高圧噴射攪拌機における施工機械１の周辺設備としては、施工機械１に取り付けた管ロッド２に硬化材や圧縮空気を供給するための設備である。硬化材はセメントミルクであるが、このセメントミルクに各種の添加剤等を混ぜ合わせるようにしても良い。そして、圧縮空気を供給するための設備としては、コンプレッサー１１であり、流量計１２を介してコンプレッサー１１から管ロッド２に圧縮空気を供給する。また、硬化材を供給するための設備としては、水中ポンプ１３を設けた混合装置１４を備え、この混合装置１４において、水中ポンプ１３を用いてセメントサイロ１５からセメント原料を流入すると共に、水中ポンプ１６を設けた水槽１７から水を流入し、これらを混合して硬化材であるセメントミルクを生成する。そして、このセメントミルクを流量計１８を介して高圧ポンプ１９から成る硬化材供給装置２０に供給し、この硬化材供給装置２０から管ロッド２にセメントミルクを供給する。なお、各装置には図示していないがそれぞれ発電機を設けている。   In addition, the peripheral equipment of the construction machine 1 in the high-pressure jet agitator is equipment for supplying a hardener or compressed air to the tube rod 2 attached to the construction machine 1. The hardener is cement milk, but various additives may be mixed with the cement milk. The equipment for supplying compressed air is the compressor 11, and the compressed air is supplied from the compressor 11 to the tube rod 2 via the flow meter 12. Moreover, as equipment for supplying the hardener, a mixing device 14 provided with a submersible pump 13 is provided. In this mixing device 14, a cement raw material is introduced from the cement silo 15 using the submersible pump 13, and a submersible pump is provided. Water is introduced from a water tank 17 provided with 16 and mixed to produce cement milk as a hardener. Then, the cement milk is supplied to the hardener supply device 20 including the high-pressure pump 19 through the flow meter 18, and the cement milk is supplied from the hardener supply device 20 to the tube rod 2. Although not shown in the drawings, each device is provided with a generator.

一方、管ロッド２の下端である先端に取り付けた特殊先端具６については、図２、図３に示すように、先端側に多数のビット３１を取り付けた掘削ヘッド３０を備えると共に、横方向の左右両側に突出する水平翼３２を備え、この水平翼３２の下部にもビット３３を取り付ける。また、水平翼３２には管ロッド２の内側と連通する噴射口３４を横方向に向けて設けており、この噴射口３４は水平翼３２の長手方向（左右方向）にわたって複数、たとえば２個の噴射口３４を横に並べるように配置し、ここからセメントミルク等を噴射する。この２個の噴射口３４にあっては、同じ方向に向けており、２個の噴射口３４からセメントミルク等が地盤中に横方向に平行な状態で噴射される。   On the other hand, as shown in FIGS. 2 and 3, the special tip 6 attached to the tip which is the lower end of the tube rod 2 is provided with an excavation head 30 attached with a number of bits 31 on the tip side, and in the lateral direction. Horizontal wings 32 projecting from the left and right sides are provided, and a bit 33 is also attached to the lower part of the horizontal wings 32. Further, the horizontal blade 32 is provided with an injection port 34 that communicates with the inside of the tube rod 2 in the lateral direction. The injection port 34 has a plurality of, for example, two, for example, in the longitudinal direction (left-right direction) of the horizontal blade 32. The injection ports 34 are arranged side by side, and cement milk or the like is injected from here. The two injection ports 34 are directed in the same direction, and cement milk or the like is injected from the two injection ports 34 into the ground in a state parallel to the lateral direction.

なお、この噴射口３４については、１個でも良いが、３個以上の複数個にしても良い。また、複数の噴射口３４を横に配置しているが、これを、図４に示すように、上下にずらして配置するようにしても良い。さらには複数の噴射口３４を設ける場合、図５に示すように、３個の噴射口３４を縦に並べるように配置しても良いし、図６に示すように、縦横両方向に並べるように配置しても良い。なお、複数の噴射口３４を縦に並べるように配置する場合は水平翼３２を備えることなく、噴射口３４を特殊先端具６の本体に設けるようにする。また、複数個の噴射口３４を設けたとき、前述したものは噴射口３４が同じ方向に向き平行な状態でセメントミルクが噴射されるようになるが、これに限定されるものではなく、噴射口３４の向きを若干異ならせることにより、噴射するセメントミルクがクロスするように噴射口３４からセメントミルクを噴射させるようにしても良い。   The number of the injection ports 34 may be one, or may be three or more. Moreover, although the several injection port 34 is arrange | positioned sideways, as shown in FIG. 4, you may make it arrange | position by shifting up and down. Further, when a plurality of injection ports 34 are provided, three injection ports 34 may be arranged vertically as shown in FIG. 5, or as shown in FIG. It may be arranged. In addition, when arrange | positioning so that the several injection nozzle 34 may be arranged vertically, the injection nozzle 34 is provided in the main body of the special tip tool 6 without providing the horizontal blade 32. FIG. In addition, when a plurality of injection ports 34 are provided, the above-described one causes cement milk to be injected with the injection ports 34 facing in the same direction and parallel, but the present invention is not limited to this. By slightly changing the direction of the mouth 34, the cement milk may be jetted from the jet port 34 so that the cement milk to be jetted crosses.

次に、このような構成となる高圧噴射攪拌機を使用して行う高圧噴射攪拌工法による地盤改良方法の例について説明する。なお、この例は、図７に示すように、建物などの既製構造物Ｋ直下における地盤を改良するときである。   Next, the example of the ground improvement method by the high-pressure jet stirring method performed using the high-pressure jet stirrer which becomes such a structure is demonstrated. In addition, this example is a time of improving the ground directly under the ready-made structure K, such as a building, as shown in FIG.

図８（ａ）に示すように、管ロッド２を取り付けた施工機械１を所定の位置に設置する。そして、図８（ｂ）に示すように、施工機械１にて管ロッド２を回動させながら地盤中に挿入して行く。このとき、管ロッド２の下端に取り付けた特殊先端具６にて地盤を掘削するが、管ロッド２の挿入を補助するため、特殊先端具６の噴射口３４から圧縮空気や水等を噴射しながら行うようにしている。そして、図８（ｃ）に示すように、管ロッド２を所定深度まで挿入した後、管ロッド２及び特殊先端具６の回動を停止する。   As shown to Fig.8 (a), the construction machine 1 which attached the pipe rod 2 is installed in a predetermined position. And as shown in FIG.8 (b), it inserts in the ground, rotating the pipe rod 2 with the construction machine 1. FIG. At this time, the ground is excavated by the special tip tool 6 attached to the lower end of the tube rod 2, but in order to assist the insertion of the tube rod 2, compressed air, water or the like is sprayed from the injection port 34 of the special tip tool 6. While doing so. And as shown in FIG.8 (c), after inserting the tube rod 2 to the predetermined depth, rotation of the tube rod 2 and the special tip tool 6 is stopped.

それから、管ロッド２の噴射口３４から地盤中にセメントミルクを高速高圧で噴射し、このセメントミルクの噴射エネルギーで地盤を切削しながら噴射したセメントミルクと地盤とを攪拌混合させ、地盤中に固結改良体Ｔを造成する作業を行う。この地盤中に造成する固結改良体としては、一定の角度の範囲内で管ロッド２を回動させ、具体的には管ロッド２の回動を三分の一回転（１２０度）させることで、図７、図９に示すように、扇形の柱状の固結改良体Ｔとするものである。   Then, cement milk is sprayed into the ground at a high speed and high pressure from the injection port 34 of the tube rod 2, and the cement milk sprayed and ground are mixed while cutting the ground with the spray energy of the cement milk. The work which produces the improvement body T is performed. As a consolidation improvement body to be created in the ground, the tube rod 2 is rotated within a certain angle range, and specifically, the tube rod 2 is rotated by one third (120 degrees). Thus, as shown in FIGS. 7 and 9, a fan-shaped columnar consolidated improvement body T is obtained.

これは、管ロッド２における特殊先端具６の２個の噴射口３４を施工する地盤の方向に向けてから管ロッド２をゆっくり回動させつつ、管ロッド２に供給されたセメントミルクと圧縮空気によって、管ロッド２における特殊先端具６の２個の噴射口３４からセメントミルクを地盤中に高速高圧で噴射する。これにより、セメントミルクの噴射エネルギーで地盤を切削しながら噴射したセメントミルクと地盤とを攪拌混合させ、地盤中に固結改良体Ｔを造成するようにしている。   This is because cement milk and compressed air supplied to the tube rod 2 while slowly rotating the tube rod 2 from the direction of the ground where the two injection ports 34 of the special tip 6 in the tube rod 2 are constructed. Thus, cement milk is injected into the ground at high speed and high pressure from the two injection ports 34 of the special tip 6 in the tube rod 2. Thereby, the cement milk sprayed while cutting the ground with the spray energy of cement milk and the ground are agitated and mixed, and the consolidation improvement body T is formed in the ground.

このように管ロッド２の噴射口３４からセメントミルクを噴射するとき、管ロッド２を回動させながら行うようにしているが、地盤中に存在する地中障害物Ｐの場所に来たとき、管ロッド２の回動を停止し、まず、図１０（ａ）に示すように、管ロッド２の噴射口３４を地盤中に存在する地中障害物Ｐの一方の際に向ける。そして、この状態にて、管ロッド２を回動させることなく停止した状態で管ロッド２の噴射口３４からセメントミルクを高速高圧で直線的に所定時間噴射し、このセメントミルクを所定時間噴射する際の噴射する時間としては、たとえば３０秒である。ただし、このセメントミルクを噴射する時間については、この３０秒に限定されるものではなく、地盤中に存在する地中障害物Ｐの大きさなどに基づいて変更するようにしている。たとえば、地中障害物Ｐの大きさが大きいと、セメントミルクを噴射する時間も長めにし、地中障害物Ｐの大きさが小さいと、セメントミルクを噴射する時間も短めにしている。なお、この地中障害物Ｐとしては、建物などの既製構造物Ｋの下に存在する基礎杭などであって、これらは予めその位置やその大きさが特定できるものである。   In this way, when the cement milk is jetted from the jet port 34 of the tube rod 2, the tube rod 2 is rotated, but when it comes to the place of the underground obstacle P existing in the ground, The rotation of the tube rod 2 is stopped. First, as shown in FIG. 10A, the injection port 34 of the tube rod 2 is directed to one of the underground obstacles P existing in the ground. In this state, cement milk is sprayed linearly at a high speed and high pressure for a predetermined time from the injection port 34 of the tube rod 2 in a state where the tube rod 2 is stopped without rotating, and the cement milk is sprayed for a predetermined time. The time for spraying at that time is, for example, 30 seconds. However, the time for injecting the cement milk is not limited to 30 seconds, and is changed based on the size of the underground obstacle P existing in the ground. For example, when the size of the underground obstacle P is large, the time for injecting cement milk is lengthened, and when the size of the underground obstacle P is small, the time for injecting cement milk is also shortened. In addition, as this underground obstruction P, it is a foundation pile etc. which exist under the ready-made structure K, such as a building, These can identify the position and the magnitude | size beforehand.

そして、管ロッド２の噴射口３４から地中障害物Ｐの一方の際に向けてセメントミルクを直線的に所定時間である３０秒噴射したのち、管ロッド２を回動させ、この管ロッド２を回動させながら管ロッド２の噴射口３４からセメントミルクを地中障害物Ｐに向けながら噴射する。そして、再び管ロッド２の回動を停止し、図１０（ｂ）に示すように、管ロッド２の噴射口３４を地中障害物Ｐの他方の際に向ける。そして、この状態にて、管ロッド２を回動させることなく停止した状態で管ロッド２の噴射口３４からセメントミルクを高速高圧で直線的に所定時間である３０秒噴射する。   And after spraying cement milk linearly for 30 seconds which is predetermined time from the injection port 34 of the tube rod 2 toward one side of the underground obstacle P, the tube rod 2 is rotated, and this tube rod 2 The cement milk is sprayed from the spray port 34 of the tube rod 2 while turning toward the underground obstacle P. Then, the rotation of the tube rod 2 is stopped again, and the injection port 34 of the tube rod 2 is directed to the other side of the underground obstacle P as shown in FIG. In this state, cement milk is sprayed linearly at high speed and high pressure for 30 seconds, which is a predetermined time, from the injection port 34 of the tube rod 2 while the tube rod 2 is stopped without being rotated.

そして、管ロッド２の噴射口３４から地中障害物Ｐの他方の際に向けてセメントミルクを直線的に所定時間噴射したのち、再び管ロッド２を回動させ、この管ロッド２を回動させながら管ロッド２の噴射口３４からセメントミルクを噴射する。それから、また地盤中に存在する地中障害物Ｐの場所に来たときは、前述と同様、管ロッド２の回動を停止し、管ロッド２の噴射口３４を地中障害物Ｐの際に向けて、管ロッド２を回動させることなく停止した状態で管ロッド２の噴射口３４からセメントミルクを高速高圧で直線的に所定時間噴射する。なお、地盤中に存在する地中障害物Ｐが非常に小さい場合は、前述したような地中障害物Ｐの両方の際に向けてセメントミルクを噴射していたのを、地中障害物Ｐの一方の際のみだけにするようにしても良い。   Then, after the cement milk is sprayed linearly from the injection port 34 of the tube rod 2 toward the other side of the underground obstacle P for a predetermined time, the tube rod 2 is rotated again, and the tube rod 2 is rotated. The cement milk is jetted from the jet port 34 of the tube rod 2 while being allowed to flow. Then, when it comes to the place of the underground obstacle P existing in the ground, the rotation of the tube rod 2 is stopped as described above, and the injection port 34 of the tube rod 2 is moved to the position of the underground obstacle P. In the state where the tube rod 2 is stopped without rotating, the cement milk is sprayed linearly at a high speed and high pressure for a predetermined time from the injection port 34 of the tube rod 2. In addition, when the underground obstacle P which exists in the ground is very small, it is the underground obstacle P which injected cement milk toward the case of the underground obstacle P as mentioned above. You may make it only at the time of one of these.

そして、図１１（ｄ）に示すように、この所定深度において地盤中に扇形の固結改良体Ｔを造成してから、管ロッド２を数センチから数十センチ引く抜き上方に移動させ、その上方の位置においても、前述と同様、管ロッド２を回動させながら管ロッド２の噴射口３４からセメントミルクを噴射し、また、地盤中に地中障害物Ｐが存在する場所では、管ロッド２の回動を停止し、その地中障害物Ｐの際に向けて、管ロッド２を回動させることなく停止した状態で管ロッド２からセメントミルクを高速高圧で直線的に所定時間噴射する。これを、図１１（ｅ）に示すように、管ロッド２を引き抜き上方に移動させながら所望の深度まで繰り返し行うことにより、地盤中に扇形の柱状の固結改良体Ｔを造成する。   Then, as shown in FIG. 11 (d), after forming a fan-shaped consolidation improvement body T in the ground at this predetermined depth, the tube rod 2 is moved upwards by pulling several centimeters to several tens of centimeters, Also in the upper position, as described above, cement milk is injected from the injection port 34 of the tube rod 2 while rotating the tube rod 2, and the tube rod 2 is used in a place where the underground obstacle P exists in the ground. 2 is stopped, and cement milk is sprayed linearly from the tube rod 2 at a high speed and high pressure for a predetermined time in a state where the tube rod 2 is stopped without rotating toward the underground obstacle P. . As shown in FIG. 11 (e), a fan-shaped columnar consolidated improvement body T is formed in the ground by repeatedly pulling the tube rod 2 and moving it up to a desired depth.

そして、最後に地盤中に固結改良体Ｔを造成したのち、図１１（ｆ）に示すように、施工機械１にて管ロッド２を地盤から引き抜くことによって、高圧噴射攪拌工法による地盤改良の作業が完了する。   Finally, after the consolidation improvement body T is created in the ground, as shown in FIG. 11 (f), the pipe rod 2 is pulled out from the ground by the construction machine 1, thereby improving the ground by the high-pressure jet stirring method. The work is complete.

このような高圧噴射攪拌工法による地盤改良方法にあっては、地盤中に地中障害物Ｐが存在する場合、この地中障害物Ｐの際に向けて、管ロッド２を回動させることなく停止した状態で管ロッド２からセメントミルクを高速高圧で直線的に所定時間である３０秒噴射することによって、管ロッド２から噴射したセメントミルクが地中障害物Ｐの背面側に廻り込むようになる。これは、地中障害物Ｐの際に向けて管ロッド２からセメントミルクを噴射すると、図１２に示すように、そのセメントミルクが地中障害物Ｐの際に当たって、当たった地中障害物Ｐの正面側の圧力が高く、地中障害物Ｐの背面側の圧力が低くなるという圧力差が生じ、この圧力差により圧力の高い方から低い方に流れるという流体の法則に従って、噴射されたセメントミルクが地中障害物Ｐの背面側に廻り込むようにして流れるようになり、地中障害物Ｐの背面側にも固結改良体Ｔが造成されるようになるものである。なお、地盤中に存在する地中障害物Ｐの大きさなどによって、地中障害物Ｐの背面側にセメントミルクが廻り込むのに時間がかかるため、前述したように、地盤中に存在する地中障害物Ｐの大きさなどに基づいて、セメントミルクの噴射する時間を変更するようにし、地中障害物Ｐの背面側に確実にセメントミルクを廻り込ませるようにする。   In the ground improvement method by such a high-pressure jet stirring method, when the underground obstacle P exists in the ground, the tube rod 2 is not rotated toward the underground obstacle P. When the cement milk is sprayed from the tube rod 2 at a high speed and high pressure for 30 seconds, which is a predetermined time, in a stopped state, the cement milk sprayed from the tube rod 2 moves around to the back side of the underground obstacle P. Become. When cement milk is jetted from the tube rod 2 toward the underground obstacle P, the cement milk hits the underground obstacle P as shown in FIG. A pressure difference occurs in which the pressure on the front side of the pipe is high and the pressure on the back side of the underground obstacle P is low, and the injected cement is in accordance with the fluid law that the pressure difference flows from the higher pressure side to the lower pressure side. The milk flows around the back side of the underground obstacle P, and the consolidation improvement body T is formed also on the back side of the underground obstacle P. In addition, since it takes time for the cement milk to go around to the back side of the underground obstacle P due to the size of the underground obstacle P existing in the ground, the ground existing in the ground as described above. Based on the size of the medium obstacle P, the time for spraying the cement milk is changed, and the cement milk is surely moved around the back side of the underground obstacle P.

なお、前述した高圧噴射攪拌工法による地盤改良方法の例において、地盤中に造成する固結改良体としては、管ロッドの回動を三分の一回転（１２０度）させた扇形の柱状の固結改良体としていたが、これに限定されるものではなく、その他の大きさ（角度）の扇形の柱状の固結改良体でも良く、さらには、管ロッドの回動を一回転（３６０度）させることにより、図１３に示すように、円柱状の固結改良体Ｔとしても良い。また、これ以外の形の固結改良体Ｔにしても良い。   In the example of the ground improvement method using the high-pressure jet agitation method described above, the consolidation improvement body to be created in the ground is a fan-shaped columnar solid body in which the tube rod is rotated by one third (120 degrees). However, the present invention is not limited to this, but may be a fan-shaped columnar consolidation improvement body of other sizes (angles), and further, the tube rod rotates once (360 degrees). By doing so, as shown in FIG. Moreover, you may make the consolidation improvement body T of a shape other than this.

また、地盤中に固結改良体Ｔを造成する方式としては、前述の例では、基本的には管ロッド２を回動させながら管ロッド２の噴射口３４からセメントミルクを噴射して地盤中に固結改良体Ｔを造成する方式のものであったが、この方式のものに限定されるものではなく、たとえば、管ロッド２を所定角度である２，３度回動させてから停止し、この停止した状態で管ロッド２の噴射口３４からセメントミルクを直線的に所定時間噴射し、噴射後、再び管ロッド２を所定角度である２，３度回動させてから停止し、この停止した状態で管ロッド２の噴射口３４からセメントミルクを直線的に所定時間噴射するといった所定角度毎にセメントミルクを噴射して地盤中に固結改良体Ｔを造成する方式のものでも良く、また、その他の固結改良体Ｔを造成する方式のものでも良い。   Further, as a method of creating the consolidation improvement body T in the ground, in the above-described example, basically, cement milk is sprayed from the spray port 34 of the tube rod 2 while the tube rod 2 is rotated. However, the present invention is not limited to this method. For example, the tube rod 2 is rotated after a predetermined angle of 2 or 3 degrees and then stopped. In this stopped state, the cement milk is linearly sprayed from the injection port 34 of the tube rod 2 for a predetermined time, and after the injection, the tube rod 2 is again rotated by a predetermined angle of 2 or 3 degrees, and then stopped. In the stopped state, the cement milk may be sprayed from the injection port 34 of the tube rod 2 linearly for a predetermined time, and the cement milk may be sprayed at a predetermined angle to form the consolidation improvement body T in the ground. In addition, other consolidation improvement body T Or it may be of a type to be formed.

１…施工機械、２…管ロッド、３…マスト、４…昇降装置、５…回動装置、６…特殊先端具、１１…コンプレッサー、１２…流量計、１３…水中ポンプ、１４…混合装置、１５…セメントサイロ、１６…水中ポンプ、１７…水槽、１８…流量計、１９…高圧ポンプ、２０…硬化材供給装置、３０…掘削ヘッド、３１…ビット、３２…水平翼、３３…ビット、３４…噴射口、４１…施工機械、４２…管ロッド、４３…噴射口   DESCRIPTION OF SYMBOLS 1 ... Construction machine, 2 ... Pipe rod, 3 ... Mast, 4 ... Lifting device, 5 ... Turning device, 6 ... Special tip, 11 ... Compressor, 12 ... Flow meter, 13 ... Submersible pump, 14 ... Mixing device, DESCRIPTION OF SYMBOLS 15 ... Cement silo, 16 ... Submersible pump, 17 ... Water tank, 18 ... Flow meter, 19 ... High pressure pump, 20 ... Hardener supply device, 30 ... Excavation head, 31 ... Bit, 32 ... Horizontal wing, 33 ... Bit, 34 ... injection port, 41 ... construction machine, 42 ... tube rod, 43 ... injection port

Claims (2)

施工機械にて地盤中に管ロッドを所定深度まで挿入し、挿入後、管ロッドから硬化材を高速高圧で噴射し、この硬化材の噴射エネルギーで地盤を切削しながら噴射した硬化材と地盤とを攪拌混合させ、地盤中に固結改良体を造成して地盤を改良するようにした高圧噴射攪拌工法による地盤改良方法において、
既設構造物の下などの地盤中に地中障害物が存在する場合、この地中障害物の際に向けて、管ロッドを回動させることなく停止した状態で管ロッドから硬化材を高速高圧で直線的に所定時間噴射し、地中障害物の背面側に噴射した硬化材を廻り込ませるようにしたことを特徴とする高圧噴射攪拌工法による地盤改良方法。 Insert the tube rod into the ground with a construction machine to a predetermined depth, and after the insertion, the hardened material is injected from the tube rod at high speed and high pressure, and the hardened material and the ground injected while cutting the ground with the injection energy of this hardened material In the ground improvement method by the high-pressure jet agitation method that improves the ground by creating a consolidation improvement body in the ground,
When there are underground obstacles in the ground such as under existing structures, high-speed and high-pressure materials are hardened from the tube rod while the tube rod is stopped without rotating toward the underground obstacle. A ground improvement method using a high-pressure jet agitation method, characterized in that the hardened material sprayed linearly for a predetermined period of time and circulated around the back side of the underground obstacle is wrapped around. 管ロッドを回動させることなく停止した状態で管ロッドから硬化材を高速高圧で直線的に所定時間噴射する際の噴射する時間を、地盤中に存在する地中障害物の大きさに基づいて変更するようにしたことを特徴とする請求項１記載の高圧噴射攪拌工法による地盤改良方法。   Based on the size of the underground obstacle existing in the ground, the time to inject the hardened material from the tube rod linearly at a high speed and high pressure for a predetermined time with the tube rod stopped without rotating. 2. The ground improvement method according to claim 1, wherein the ground is improved.
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JPH07109093B2 (en) * 1989-06-01 1995-11-22 株式会社エヌ、アイ、ティ Ground hardening material High pressure injection injection method
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