JP2000054368A - High-pressure jet mixing ground-improvement method - Google Patents
High-pressure jet mixing ground-improvement methodInfo
- Publication number
- JP2000054368A JP2000054368A JP10225710A JP22571098A JP2000054368A JP 2000054368 A JP2000054368 A JP 2000054368A JP 10225710 A JP10225710 A JP 10225710A JP 22571098 A JP22571098 A JP 22571098A JP 2000054368 A JP2000054368 A JP 2000054368A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- ground
- nozzle
- injection
- hardening material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高圧液を噴射し地盤を
切削するとともに切削土砂と硬化材を混合・攪拌し地盤
硬化体を造成する高圧噴射攪拌混合地盤改良工法に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure, jet-stirring and mixing ground improvement method for cutting a ground by injecting a high-pressure liquid and mixing and stirring the cut soil and hardening material to form a hardened ground.
【０００２】[0002]
【従来の技術】従来、高圧噴射地盤改良工法としては、
いわゆる「ＪＳＧ工法」や「コラムジェット工法」が主
流であり現在も多用されている。2. Description of the Related Art Conventionally, as a high-pressure injection ground improvement method,
The so-called “JSG method” and “column jet method” are mainstream and are still frequently used.
【０００３】「ＪＳＧ工法」とは、硬化材を噴射する核
ノズルと核ノズルの周囲を包囲しエアを噴射する包囲ノ
ズルとから構成される高圧噴射ノズルを先端部に設けた
注入管を地中に挿入し、この噴射ノズルからエアを伴っ
た硬化材を高圧噴射する工法である。[0003] The "JSG method" refers to an underground injection pipe provided with a high-pressure injection nozzle comprising a core nozzle for injecting a hardening material, and a surrounding nozzle for surrounding the core nozzle and injecting air. And a high-pressure injection of a hardening material accompanied by air from the injection nozzle.
【０００４】また「コラムジェット工法」とは、注入管
先端部の下段に設けた硬化材噴射ノズルとその上段に設
けた高圧水を噴射する核ノズルとその周囲を包囲しエア
を噴射する包囲ノズルとから構成される高圧水噴射ノズ
ルによって、まず上段の高圧水噴射ノズルからエアを伴
った高圧水を噴射し地盤を切削したのち、下段の硬化材
噴射ノズルから硬化材を噴射する工法である。[0004] The "column jet method" refers to a hardening material injection nozzle provided at a lower portion of a tip end portion of an injection pipe, a nucleus nozzle provided at an upper portion thereof for injecting high-pressure water, and an encircling nozzle for surrounding and injecting air around the nozzle. This is a method in which high pressure water with air is injected from the upper high pressure water injection nozzle to cut the ground, and then the hardening material is injected from the lower hardening material injection nozzle.
【０００５】これらの工法は、いずれも硬化材噴射工程
と圧縮エアの伴う切削工程とほぼ同一工程で行うため、
地盤中に噴射した硬化材がエアリフト効果により切削泥
水に混じり、泥水と一緒に地上に排出されるという問題
があった。[0005] Since these methods are performed in almost the same steps as the hardening material injection step and the cutting step involving compressed air,
There is a problem that the hardened material injected into the ground mixes with the cutting muddy water by an air lift effect and is discharged to the ground together with the muddy water.
【０００６】そこで最近では、このような硬化材の排出
を抑制するためエアを伴う高圧水による切削工程と硬化
材の注入工程とを別工程で行う種々の技術が、たとえば
特開平９−１４３９７５号公報などによって提案されて
いる。In recent years, various techniques for suppressing the discharge of the hardened material, in which a cutting process using high-pressure water with air and a hardening material injection process are performed in separate processes, are disclosed in, for example, JP-A-9-143975. It has been proposed in gazettes and the like.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、この種
技術にも次に示すような問題点があった。すなわち、高
圧水による切削工程と硬化材の注入工程を別工程で行う
ため、切削工程と注入工程との間にかなりの時間差が生
じる。そのため切削工程において泥水または泥状化した
地盤改良領域の孔壁が崩壊したり又は泥水中の土砂類が
沈降したりすることによって、地盤改良領域の下方に土
砂類が滞積し、これが後工程の硬化材注入の障害とな
り、硬化体下端部分の杭径を細くしたり、未固結部分が
生じたりして、計画寸法通りの硬化体が造成できない。However, this type of technology has the following problems. That is, since the cutting step using high-pressure water and the injection step of the hardening material are performed in separate steps, a considerable time difference occurs between the cutting step and the injection step. Therefore, in the cutting process, muddy water or muddy soil in the ground improvement area collapses or the sediment in the muddy water settles, causing sediment to accumulate below the ground improvement area, and this causes post-processing. As a result, the diameter of the pile at the lower end of the hardened material is reduced, and an unconsolidated portion is formed, so that the hardened material cannot be formed as planned.
【０００８】また、滞積した土砂類が硬化材注入の障害
となるため、硬化材の注入速度と硬化材と泥状物との置
換速度との均衡が崩れ、硬化材が上方に逸走しやすくな
る。In addition, since the accumulated sediment hinders the injection of the hardening material, the balance between the speed of injecting the hardening material and the speed of replacing the hardening material with the muddy material is broken, and the hardening material easily escapes upward. Become.
【０００９】したがって、硬化材が泥水等に混じり、地
上に排出されてしまう。このような硬化材混じりの泥状
物は、廃棄物としての処理も困難であり、処理コストも
高い。また、硬化材が地上に排出される分だけ、余分な
硬化材を使用しなければならず、材料コストも嵩む。Therefore, the hardening material is mixed with muddy water and discharged to the ground. Such a mud mixed with a hardening material is difficult to treat as waste, and the treatment cost is high. In addition, since the hardened material is discharged to the ground, an extra hardened material must be used, which increases the material cost.
【００１０】以上のような問題の発生は対象地盤が砂質
土の場合に特に顕著である。[0010] The occurrence of the above problems is particularly remarkable when the target ground is sandy soil.
【００１１】本発明は以上の問題点を鑑みてなされたも
ので、硬化材混じりの泥状物を極力地上部に排出せず、
しかも計画寸法通りの硬化体を造成することのできる高
圧噴射地盤攪拌混合改良工法を提案することを課題とす
る。The present invention has been made in view of the above problems, and does not discharge mud containing a hardening material to the ground as much as possible.
Moreover, an object of the present invention is to propose a high-pressure injection ground stirring and mixing improvement method capable of forming a hardened body having the planned dimensions.
【００１２】[0012]
【課題を解決するための手段】上記課題を解決した本発
明の請求項１記載の発明は、次の工程を含む、高圧液を
噴射し地盤を切削するとともに切削土砂と硬化材を混合
・攪拌し硬化体を造成することを特徴とする高圧噴射攪
拌混合地盤改良工法である。Means for Solving the Problems The invention according to claim 1 of the present invention, which has solved the above-mentioned problems, comprises the following steps: a step of injecting a high-pressure liquid to cut the ground, and mixing and stirring the cut soil and hardened material. This is a high-pressure injection-stirring / mixing ground improvement method characterized by forming a hardened body.
【００１３】（１）高圧液を噴射する核ノズルとこの核
ノズルの周囲から圧縮エアを噴射する包囲ノズルとを有
する高圧噴射ノズルを先端部に設けた注入管を地盤中に
挿入する工程。(1) A step of inserting, into the ground, an injection pipe provided with a high-pressure injection nozzle having a core nozzle for jetting a high-pressure liquid and a surrounding nozzle for jetting compressed air from around the core nozzle.
【００１４】（２）前記高圧噴射ノズルからエアを伴っ
た高圧液を側方に高圧噴射し、前記注入管を回転させな
がら地盤改良上限位置まで引き上げることによって、地
盤を切削するとともに、エアリフト効果により切削土砂
を地上に排出し、泥状の地盤改良予定領域を形成する工
程。(2) The high-pressure liquid with air is injected from the high-pressure injection nozzle to the side at a high pressure, and the injection pipe is rotated to raise the soil to the upper limit of the soil improvement. A process of discharging cutting earth and sand to the ground to form a muddy ground improvement area.
【００１５】（３）前記高圧噴射ノズルから高圧液の
み、またはエアを伴った高圧液を側方に高圧噴射させな
がら、前記注入管を地盤改良下限位置まで再度挿入する
ことによって、地盤改良予定領域を再切削および攪拌の
少なくとも一方を行う工程。(3) The injection pipe is reinserted to the ground improvement lower limit position while the high pressure liquid alone or the high pressure liquid accompanied by air is jetted from the high pressure injection nozzle to the side at a high pressure. Performing at least one of re-cutting and stirring.
【００１６】（４）前記注入管を引き上げながらその注
入管の先端部から液状の硬化材を噴射し、前工程で泥状
化した地盤改良予定領域の泥状物と硬化材を混合および
攪拌するとともに余剰の泥状物を地上に排出する工程。(4) A liquid hardening material is sprayed from the tip of the injection pipe while pulling up the injection pipe, and the hardened material and the muddy material in the ground improvement scheduled area which has been muddy in the previous process are mixed and stirred. Together with the process of discharging excess mud to the ground.
【００１７】請求項２記載の発明は、高圧液噴射ノズル
は、高さ方向に複数有し、その上方のものは下方の向か
って噴射するようにし、下方のものは上方に向かって噴
射するようにした請求項１記載の高圧噴射攪拌混合地盤
改良工法である。According to a second aspect of the present invention, a plurality of high-pressure liquid injection nozzles are provided in the height direction, and the high-pressure liquid injection nozzles are configured to eject downwardly, and the lower ones are ejected upwardly. The high-pressure injection-stirred-mixing ground improvement method according to claim 1.
【００１８】[0018]
【発明の実施の形態】以下本発明を図面に示す実施の形
態によってさらに詳説する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the embodiments shown in the drawings.
【００１９】（１）削孔工程 本発明で使用する注入管１は、たとえば図５に示す注入
管１が用いられる。すなわち、注入管１は３流路管であ
り、中央に削孔水Ｗおよび硬化材Ｈ用流路２と高圧液Ｌ
用流路３と圧縮エアＡ用流路４の３流路を有し、その先
端部にはウイングビット等の削孔ビット５が取り付けら
れている。(1) Drilling Step As the injection pipe 1 used in the present invention, for example, the injection pipe 1 shown in FIG. 5 is used. That is, the injection pipe 1 is a three-flow pipe, and the drilling water W and the hardening material H flow path 2 and the high-pressure liquid L
There are three flow paths, i.e., a flow path 3 for compressed air and a flow path 4 for compressed air A, and a drill bit 5 such as a wing bit is attached to a tip end thereof.
【００２０】この削孔ビットには、削孔水Ｗを吐出させ
る吐出孔６が形成されている。この上部には、硬化材噴
射ノズル７が設けられている。この硬化材噴射ノズル７
と吐出孔６の流路方向の切替えは、注入管先端に内蔵さ
れた切替バルブ８により行われる。この切替えバルブ８
は、反発スプリング８Ａに基部側に付勢された弁座８Ｂ
とこの弁座８Ｂに向かって投入されるボール８Ｃとによ
り構成され、削孔水Ｗの供給時には、ボール８Ｃは投入
されていないので、供給される削孔水Ｗは、流路２を通
してそのまま吐出孔６から吐出される。硬化材Ｈの供給
に際しては、ボール８Ｃが投入され、その結果、切替え
バルブ８より先端側がボール８Ｃにより封止されるの
で、供給された硬化材Ｈは硬化材噴射ノズル７から噴出
されるようになる。The drill bit is provided with a discharge hole 6 for discharging drill water W. Above this, a hardener injection nozzle 7 is provided. This hardener injection nozzle 7
The switching of the flow direction of the discharge hole 6 and the discharge hole 6 is performed by a switching valve 8 built in the tip of the injection pipe. This switching valve 8
Is a valve seat 8B biased toward the base side by a repulsion spring 8A.
And the ball 8C to be thrown toward the valve seat 8B. When the drilling water W is supplied, since the ball 8C is not thrown, the supplied drilling water W is directly discharged through the flow path 2. Discharged from the hole 6. When the hardening material H is supplied, the ball 8C is thrown in, and as a result, the tip side of the switching valve 8 is sealed by the ball 8C, so that the supplied hardening material H is ejected from the hardening material injection nozzle 7. Become.
【００２１】さらに、硬化材噴射ノズル７の上方位置に
は高圧液Ｌ用流路３に連通した高圧液噴射用核ノズル９
Ａと、圧縮エア用流路４に連通し、前記核ノズル９Ａの
周囲を包囲しエアＡを噴射する包囲ノズル９Ｂとから構
成された、エアを伴う高圧液を側方に高圧噴射するため
の高圧噴射ノズル９が上下２ヶ所に相反する方向に噴射
するように設けられている。下部側の高圧噴射ノズル９
は所定角度斜め上向きに、一方、上部側の高圧噴射ノズ
ル９は所定角度斜め下向きに設けられている。Further, a high pressure liquid injection core nozzle 9 communicating with the high pressure liquid L flow path 3 is located above the hardening material injection nozzle 7.
A and a surrounding nozzle 9B which communicates with the compressed air flow path 4 and surrounds the core nozzle 9A and injects the air A. A high-pressure injection nozzle 9 is provided so as to inject in two opposite directions in opposite directions. Lower high-pressure injection nozzle 9
Is directed obliquely upward at a predetermined angle, while the upper high-pressure injection nozzle 9 is provided obliquely downward at a predetermined angle.
【００２２】さて、図１に示すように、かかる注入管１
を用い、ボーリングマシン等の削孔装置１０を用い、前
記注入管１先端の吐出孔６から削孔水Ｗを吐出させなが
ら地盤改良予定下限位置に、注入管１の先端部が到達す
るまで地盤を削孔し、この注入管１を所定位置に配置す
る。Now, as shown in FIG.
Using a drilling machine 10 such as a boring machine, while discharging drilling water W from the discharge hole 6 at the tip of the injection pipe 1, the ground is maintained until the tip of the injection pipe 1 reaches the ground improvement planned lower limit position. And the injection pipe 1 is arranged at a predetermined position.
【００２３】（２）一次切削工程 次いで、図２に示すように、地盤改良予定下限位置か
ら、高圧噴射ノズル９，９からエアを伴った高圧液を側
方に高圧噴射させつつ、注入管１を地盤改良上限位置ま
で回転させながら引き上げることによって地盤を切削す
るとともに、圧縮エアの同伴に伴うエアリフト効果によ
り切削土砂を地上に排出し、泥状の地盤改良予定領域を
形成する。(2) Primary Cutting Step Next, as shown in FIG. 2, the injection pipe 1 is injected from the high-pressure injection nozzles 9, 9 while the high-pressure liquid with air is injected from the lower limit of the ground improvement plan to the side. The ground is cut by rotating it up to the ground improvement upper limit position and cutting the ground, and the cut soil is discharged to the ground by the air lift effect accompanying the compressed air to form a muddy ground improvement scheduled area.
【００２４】この際使用する高圧液（切削水）Ｌとして
はこの切削工程で形成した泥状化領域の孔壁保持性およ
び硬化材注入工程時における置換性の点から、増粘剤の
添加された１００〜７５０ｍＰａ・ｓの範囲の粘度を有
するものが好適である。粘度が１００ｍＰａ・ｓより低
いと泥状化領域Ｚの孔壁が崩壊しやすくなり、また７５
０ｍＰａ・ｓより高くなると後工程での硬化材が目標域
に注入されず、上方に逸走して余剰泥状物と一緒に排出
されてしまう傾向が大きい。As the high-pressure liquid (cutting water) L used at this time, a thickener is added from the viewpoint of the hole wall retention of the muddy region formed in this cutting step and the substitution during the hardening material injection step. Those having a viscosity in the range of 100 to 750 mPa · s are also suitable. When the viscosity is lower than 100 mPa · s, the pore wall of the muddy zone Z is apt to collapse,
When the pressure is higher than 0 mPa · s, the hardening material in the post-process is not injected into the target area, but tends to run upward and be discharged together with the excess mud.
【００２５】この点については後述の実験例においてさ
らに説明する。ここで使用する増粘剤としてはセルロー
ス系、アクリル系、天然高分子系、繊維状鉱物系など種
々のものを使用することができる。This point will be further described in an experimental example described later. As the thickener used here, various types such as a cellulose type, an acrylic type, a natural polymer type, a fibrous mineral type and the like can be used.
【００２６】また、高圧液も噴射圧力は、この高圧液を
圧送する高圧ポンプ１１の元圧で約２００〜７００Ｋgf
／cm2 、一方、圧縮エアの圧力はエアを搬送するコンプ
レッサ１２の元圧で５〜１０Ｋｇｆ／cm2 に設定するの
が好適である。The injection pressure of the high-pressure liquid is about 200 to 700 kgf at the original pressure of the high-pressure pump 11 for pumping the high-pressure liquid.
/ Cm 2, on the other hand, the pressure of the compressed air is preferably set to 5 to 10 kgf / cm 2 as the original pressure of the compressor 12 for conveying the air.
【００２７】地上部に排出された切削液と土砂の混合物
からなる排泥Ｍは、排泥ポンプ装置１３によりピットか
ら脱水装置（図示せず）に送り込んで、土砂分と液状分
とに分離し、分離した液状分はさらに凝集処理等を施
し、切削液や削孔水として再利用するのが望ましい。切
削工程で排出される泥状物には硬化材がほとんど含まれ
ていないため、再利用のための処理がしやすい。一方、
分離した土砂分はダンプトラック等で搬出し適正に処分
する。The sludge M, which is a mixture of cutting fluid and earth and sand discharged to the ground, is sent from the pit to a dewatering device (not shown) by a sludge pump 13 to be separated into earth and sand and liquid. It is preferable that the separated liquid is subjected to a coagulation treatment or the like and reused as a cutting fluid or drilling water. Since the hard material is hardly contained in the mud discharged in the cutting process, it can be easily processed for reuse. on the other hand,
The separated sediment should be carried out by dump trucks and disposed of properly.
【００２８】（３）二次切削・攪拌工程 次いで、図３に示すように、高圧噴射ノズル９，９から
高圧液またはエアを伴った高圧液を側方に高圧噴射させ
ながら、注入管１を地盤改良下限位置まで再度挿入する
ことによって、地盤改良予定領域を再切削及び／又は攪
拌する。(3) Secondary Cutting and Stirring Step Next, as shown in FIG. 3, the injection pipe 1 is ejected from the high-pressure injection nozzles 9 and 9 while the high-pressure liquid or the high-pressure liquid with air is injected to the side at high pressure. By re-inserting to the ground improvement lower limit position, the ground improvement scheduled area is re-cut and / or agitated.
【００２９】このように再度、注入管１を下降さながら
高圧液等を噴射することによって、地盤改良予定領域の
孔壁崩壊や該領域中の土砂粒子の沈降によりその下端に
滞積した土砂分を攪乱し、滞積した土砂を再度、地盤改
良予定領域中に浮遊または分散させる。By injecting high-pressure liquid or the like again while lowering the injection pipe 1 in this manner, the sediment accumulated at the lower end due to the collapse of the pore wall in the area where the ground is to be improved and the sedimentation of sediment particles in the area are reduced. The disrupted sediment is suspended or dispersed again in the ground improvement area.
【００３０】二次切削・攪拌の目的は地盤の切削という
よりも地盤改良予定領域を再攪拌し、下端に滞積した土
砂を地盤改良予定領域中に再浮遊または再分散させるこ
とにあるため、噴射圧力は一次切削時よりも低く設定し
てもよい。The purpose of the secondary cutting / stirring is not to cut the ground, but to re-stir the ground improvement area and re-suspend or re-disperse the sediment accumulated at the lower end in the ground improvement area. The injection pressure may be set lower than at the time of primary cutting.
【００３１】また、上記のように滞積した土砂を再浮遊
または再分散するのに、地盤改良予定領域の全長に渡っ
て行う必要のない場合には、下限付近のみ二次切削・攪
拌を行うこともある。When it is not necessary to re-suspend or re-disperse the accumulated soil as described above over the entire length of the ground improvement scheduled area, secondary cutting and stirring are performed only near the lower limit. Sometimes.
【００３２】また、一次切削で形成した地盤改良予定領
域の杭径を何らかの方法により測定し、杭径が不十分な
ことが判明している場合には、その部分に再度高圧液を
噴射し、所定の径になるように切削することもできる。Further, the diameter of the pile in the ground improvement planned area formed by the primary cutting is measured by any method, and when it is found that the pile diameter is insufficient, the high-pressure liquid is injected again to that part, It can also be cut to a predetermined diameter.
【００３３】（４）硬化材噴射工程 次に、図４に示すように、注入管１を順次引き上げなが
ら、グラウトポンプ１４により硬化材Ｈを注入管１内に
送り込んで、その先端付近の硬化材噴射ノズル７からス
ラリー状の硬化材Ｈを噴射し、泥状化領域Ｚの泥状物と
硬化材Ｈを混合するとともに余剰の泥状物を地上に排出
して地盤中に硬化体を造成する。(4) Curing Material Injection Step Next, as shown in FIG. 4, the grout pump 14 feeds the hardening material H into the filling tube 1 while sequentially pulling up the filling tube 1, and the hardening material near the tip thereof. The slurry-like hardening material H is sprayed from the spray nozzle 7 to mix the muddy material in the muddy region Z and the hardening material H, and discharge excess muddy material to the ground to form a hardened material in the ground. .
【００３４】この硬化材としては、注入した硬化材を目
標域に確実に注入させ、上方に逸走するのを防ぐため
に、水／セメント比１００％のセメントスラリーに対
し、増粘剤の添加された１５０〜２０００ｍＰａ・ｓの
範囲の粘度を呈するものを使用し、特に２５０〜５００
ｍＰａ・ｓの粘度を呈するものが好適である。As this hardening material, a thickener was added to a cement slurry having a water / cement ratio of 100% in order to ensure that the injected hardening material was injected into the target area and to prevent upward runaway. Use a material exhibiting a viscosity in the range of 150 to 2000 mPa · s, particularly 250 to 500
Those exhibiting a viscosity of mPa · s are preferred.
【００３５】粘度が１５０ｍＰａ・ｓより低いと、泥状
化領域中に注入した硬化材が 上方に逸走しやすく、硬
化材混じりの泥状物が排出されてしまう。一方、１５０
０ｍＰａ・ｓより高くすると、使用する増粘剤の添加量
が過剰となりコスト高になるとともに粘性が高すぎて硬
化材の圧送ラインで閉塞トラブルが発生しやすくなる。
また、ここで使用する増粘剤としてはセルロース系、ア
クリル系、天然高分子系、繊維状鉱物系など種々のもの
を使用することができる。If the viscosity is lower than 150 mPa · s, the hardened material injected into the muddy region easily escapes upward, and the mud mixed with the hardened material is discharged. On the other hand, 150
If it is higher than 0 mPa · s, the amount of the thickener to be used is excessive and the cost is increased, and the viscosity is too high, so that a blocking trouble easily occurs in the pressure feed line of the hardening material.
In addition, as the thickener used here, various types such as a cellulose type, an acrylic type, a natural polymer type, and a fibrous mineral type can be used.
【００３６】硬化材の吐出圧力は、グラウトポンプ１４
の元圧で２０〜２００Ｋｇｆ／cm2にするのが好適であ
り、切削工程での高圧液の吐出圧力よりかなり低圧力に
設定される。The discharge pressure of the hardening material is controlled by the grout pump 14.
The source pressure is preferably 20 to 200 kgf / cm 2 , and is set to a pressure considerably lower than the discharge pressure of the high-pressure liquid in the cutting process.
【００３７】[0037]
【実施例】図１〜図４に示す工程をもって、図５に示す
注入管を用いて砂質地盤を対象に本発明の実験を行っ
た。EXAMPLE An experiment of the present invention was conducted on the sandy ground using the injection pipe shown in FIG. 5 in the steps shown in FIGS.
【００３８】すなわち、注入管を砂質地盤中に建て込み
注入管の核ノズルから清水（切削水）を４００Ｋｇｆ／
cm2 の圧力で噴射し、包囲ノズルから圧縮空気を１０Ｋ
ｇｆ／cm2 の圧力を噴射することにより切削工程を実施
した。That is, the injection pipe is erected in the sandy ground, and fresh water (cutting water) is supplied from the core nozzle of the injection pipe at 400 kgf / cut.
Inject with a pressure of 2 cm2, and pressurized air from surrounding nozzle at 10K
The cutting step was performed by injecting a pressure of gf / cm 2 .
【００３９】次いで切削工程で形成した泥状化領域中に
再度注入管を回転させながら最下端まで建て込むと同時
に、核ノズルから清水（高圧液）を１５０Ｋｇｆ／cm2
の圧力で噴射するとともに、包囲ノズルから圧縮空気を
１０Ｋｇｆ／cm2 の圧力で噴射することによって泥状化
領域を再攪拌（二次切削・攪拌）し、次いで注入管を回
転させながら硬化材噴射ノズルから水／セメント比１０
０％のセメントスラリー（硬化材）を５０Ｋｇｆ／cm2
の圧力で吐出させ、改良上限位置まで注入管を順次引き
上げることによって硬化材注入工程を実施し、硬化体
（直径約２，４００、長さ１０ｍ）の造成を行った。切
削工程では切削水の吐出量を２５０リットル／ｍｉｎ、
引き上げ速度を１５秒／ピッチ（１ピッチ＝２５mm）に
設定し、二次切削・攪拌工程では高圧液の吐出量は１５
０リットル／ｍｉｎ、引き上げ速度を５秒／ピッチ、硬
化材注入工程では硬化材の吐出量を２００リットル／ｍ
ｉｎ、引き上げ速度を３０秒／ピッチに設定し実施し
た。Next, at the same time as the injection pipe is rotated to the lowermost end in the muddy region formed in the cutting step while rotating the injection pipe, 150 kgf / cm 2 of fresh water (high-pressure liquid) is supplied from the core nozzle.
At the same time, and the compressed air is injected from the surrounding nozzle at a pressure of 10 kgf / cm 2 to re-stir the muddy region (secondary cutting / stirring), and then inject the hardened material while rotating the injection pipe. Water / cement ratio 10 from nozzle
0% cement slurry (hardening material) is applied to 50 kgf / cm 2
, And by sequentially pulling up the injection pipe to the improved upper limit position, a hardening material injection step was performed to form a hardened body (diameter: about 2,400, length: 10 m). In the cutting process, the discharge rate of cutting water is 250 liter / min,
The lifting speed was set to 15 seconds / pitch (1 pitch = 25 mm), and the discharge amount of the high-pressure liquid was 15 in the secondary cutting / stirring process.
0 liter / min, lifting speed 5 seconds / pitch, and in the curing material injection step, the discharge amount of the curing material was 200 liter / m.
in, the lifting speed was set to 30 seconds / pitch.
【００４０】この際、硬化材注入工程において地上に排
出される泥状物のＰＨ値を測定したところ８．６以下の
値を示し、また目視でもセメント分の排出は確認され
ず、硬化材注入工程においてセメント分はほとんど排出
されないという良好な結果が得られた。At this time, when the PH value of the mud discharged to the ground in the hardening material injection step was measured, it showed a value of 8.6 or less, and no discharge of cement was confirmed by visual inspection. Good results were obtained in which almost no cement was discharged during the process.
【００４１】さらに、造成数日後、地盤から硬化体を掘
り出し出来形の確認をしたところ、硬化体の下端部分に
おいても所定寸法の杭径が確保され、また採取したコア
サンプルの圧縮強度も８３Ｋｇｆ／cm2 と十分な強度を
有しており、未固結部分のない、寸法通りの硬化体が造
成できたことが確認された。Further, a few days after the formation, the hardened body was dug out from the ground and confirmed to be formed. As a result, a pile diameter of a predetermined size was secured at the lower end of the hardened body, and the compressive strength of the collected core sample was also 83 kgf / kg. It was confirmed that the cured product had a sufficient strength of cm 2, and had no unconsolidated portion, and could be formed according to dimensions.
【００４２】[0042]
【発明の効果】以上のとおり、本発明によれば、泥状の
地盤改良予定領域を高圧液によって二次切削・攪拌し、
その直後に硬化材の注入を開始するため、土砂分が浮遊
又は分散している状態の地盤改良予定領域に硬化材が噴
射されることとなり、噴射した硬化材は目標領域に正確
に注入され、かつその領域の泥状物と確実に混合攪拌さ
れる。その結果、未固結部分が生じたり、杭径が細まる
ことがなく、計画寸法通りの硬化体を造成することがで
きる。As described above, according to the present invention, the muddy ground improvement area is secondarily cut and agitated by high-pressure liquid,
Immediately after that, to start the injection of the hardening material, the hardening material will be injected into the ground improvement scheduled area where the soil and sand are floating or dispersed, and the injected hardening material is accurately injected into the target area, And, it is surely mixed and stirred with the mud in the region. As a result, an unconsolidated portion does not occur and the pile diameter does not decrease, and a hardened body having the planned dimensions can be formed.
【００４３】また、上述の通り、噴射した硬化材が目標
領域に確実に注入されるので、予め計画した硬化材の注
入・充填速度と、注入・充填した硬化材と泥状化物の置
換速度との均衡が保たれる。よって、硬化材が上方に逸
走し、余剰の泥状物と一緒に地上に排出されるのを防止
することができる。Further, as described above, the injected hardening material is reliably injected into the target area, so that the injection speed and the filling speed of the hardening material planned in advance and the replacement speed of the injected hardening material and the muddy material are reduced. Is balanced. Therefore, it is possible to prevent the hardened material from escaping upward and being discharged to the ground together with the excess mud.
【図１】本発明の第１工程の説明図である。FIG. 1 is an explanatory view of a first step of the present invention.
【図２】本発明の第２工程の説明図である。FIG. 2 is an explanatory view of a second step of the present invention.
【図３】本発明の第３工程の説明図である。FIG. 3 is an explanatory view of a third step of the present invention.
【図４】本発明の第４工程の説明図である。FIG. 4 is an explanatory view of a fourth step of the present invention.
【図５】注入管例の縦断面図である。FIG. 5 is a longitudinal sectional view of an example of an injection tube.
１…注入管、２…削孔水硬化材用流路、３…高圧圧液用
流路、４…圧縮エア用流路４、５…削孔ビット、６…吐
出孔、７…硬化材噴射ノズル、８…切替えバルブ、９…
高圧噴射ノズル。DESCRIPTION OF SYMBOLS 1 ... Injection pipe, 2 ... Flow path for drilling water hardening material, 3 ... Flow path for high-pressure hydraulic fluid, 4 ... Flow path for compressed air 4,5 ... Drilling bit, 6 ... Discharge hole, 7 ... Hardening material injection Nozzle, 8 ... Switching valve, 9 ...
High pressure injection nozzle.
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１１年３月５日（１９９９．３．５）[Submission date] March 5, 1999 (1999.3.5)
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】全文[Correction target item name] Full text
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【書類名】明細書[Document Name] Statement
【発明の名称】高圧噴射攪拌混合地盤改良工法[Title of the Invention] High-pressure jet stirring and mixing ground improvement method
【特許請求の範囲】[Claims]
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】本発明は、高圧液を噴射し地盤を
切削するとともに切削土砂と硬化材を混合・攪拌し地盤
硬化体を造成する高圧噴射攪拌混合地盤改良工法に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure, jet-stirring and mixing ground improvement method for cutting a ground by injecting a high-pressure liquid and mixing and stirring the cut soil and hardening material to form a hardened ground.
【０００２】[0002]
【従来の技術】従来、高圧噴射地盤改良工法としては、
いわゆる「ＪＳＧ工法」や「コラムジェット工法」が主
流であり現在も多用されている。2. Description of the Related Art Conventionally, as a high-pressure injection ground improvement method,
The so-called “JSG method” and “column jet method” are mainstream and are still frequently used.
【０００３】「ＪＳＧ工法」とは、硬化材を噴射する核
ノズルと核ノズルの周囲を包囲しエアを噴射する包囲ノ
ズルとから構成される高圧噴射ノズルを先端部に設けた
注入管を地中に挿入し、この噴射ノズルからエアを伴っ
た硬化材を高圧噴射する工法である。[0003] The "JSG method" refers to an underground injection pipe provided with a high-pressure injection nozzle comprising a core nozzle for injecting a hardening material, and a surrounding nozzle for surrounding the core nozzle and injecting air. And a high-pressure injection of a hardening material accompanied by air from the injection nozzle.
【０００４】また「コラムジェット工法」とは、注入管
先端部の下段に設けた硬化材噴射ノズルとその上段に設
けた高圧水を噴射する核ノズルとその周囲を包囲しエア
を噴射する包囲ノズルとから構成される高圧水噴射ノズ
ルによって、まず上段の高圧水噴射ノズルからエアを伴
った高圧水を噴射し地盤を切削したのち、下段の硬化材
噴射ノズルから硬化材を噴射する工法である。[0004] The "column jet method" refers to a hardening material injection nozzle provided at a lower portion of a tip end portion of an injection pipe, a nucleus nozzle provided at an upper portion thereof for injecting high-pressure water, and an encircling nozzle for surrounding and injecting air around the nozzle. This is a method in which high pressure water with air is injected from the upper high pressure water injection nozzle to cut the ground, and then the hardening material is injected from the lower hardening material injection nozzle.
【０００５】これらの工法は、いずれも硬化材噴射工程
と圧縮エアを伴う切削工程とほぼ同一工程で行うため、
地盤中に噴射した硬化材がエアリフト効果により切削泥
水に混じり、泥水と一緒に地上に排出されるという問題
があった。[0005] To perform these method are all at substantially the same process and the cutting process with the compressed air and cured material injection step,
There is a problem that the hardened material injected into the ground mixes with the cutting muddy water by an air lift effect and is discharged to the ground together with the muddy water.
【０００６】そこで最近では、このような硬化材の排出
を抑制するためエアを伴う高圧水による切削工程と硬化
材の注入工程とを別工程で行う種々の技術が、たとえば
特開平９−１４３９７５号公報などによって提案されて
いる。In recent years, various techniques for suppressing the discharge of the hardened material, in which a cutting process using high-pressure water with air and a hardening material injection process are performed in separate processes, are disclosed in, for example, JP-A-9-143975. It has been proposed in gazettes and the like.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、この種
の技術にも次に示すような問題点があった。すなわち、
高圧水による切削工程と硬化材の注入工程を別工程で行
うため、切削工程と注入工程との間にかなりの時間差が
生じる。そのため切削工程において泥水または泥状化し
た地盤改良領域の孔壁が崩壊したり又は泥水中の土砂類
が沈降したりすることによって、地盤改良領域の下方に
土砂類が滞積し、これが後工程の硬化材注入の障害とな
り、硬化体下端部分の杭径を細くしたり、未固結部分が
生じたりして、計画寸法通りの硬化体が造成できない。SUMMARY OF THE INVENTION However, this kind of
The technique described above also has the following problems. That is,
Since the cutting step using high-pressure water and the injection step of the hardening material are performed in separate steps, a considerable time difference occurs between the cutting step and the injection step. Therefore, in the cutting process, muddy water or muddy soil in the ground improvement area collapses or the sediment in the muddy water settles, causing sediment to accumulate below the ground improvement area, and this causes post-processing. As a result, the diameter of the pile at the lower end of the hardened material is reduced, and an unconsolidated portion is formed, so that the hardened material cannot be formed as planned.
【０００８】また、滞積した土砂類が硬化材注入の障害
となるため、硬化材の注入速度と硬化材と泥状物との置
換速度との均衡が崩れ、硬化材が上方に逸走しやすくな
る。In addition, since the accumulated sediment hinders the injection of the hardening material, the balance between the speed of injecting the hardening material and the speed of replacing the hardening material with the muddy material is broken, and the hardening material easily escapes upward. Become.
【０００９】したがって、硬化材が泥水等に混じり、地
上に排出されてしまう。このような硬化材混じりの泥状
物は、廃棄物としての処理も困難であり、処理コストも
高い。また、硬化材が地上に排出される分だけ、余分な
硬化材を使用しなければならず、材料コストも嵩む。Therefore, the hardening material is mixed with muddy water and discharged to the ground. Such a mud mixed with a hardening material is difficult to treat as waste, and the treatment cost is high. In addition, since the hardened material is discharged to the ground, an extra hardened material must be used, which increases the material cost.
【００１０】以上のような問題の発生は対象地盤が砂質
土の場合に特に顕著である。[0010] The occurrence of the above problems is particularly remarkable when the target ground is sandy soil.
【００１１】本発明は以上の問題点を鑑みてなされたも
ので、硬化材混じりの泥状物を極力地上部に排出せず、
しかも計画寸法通りの硬化体を造成することのできる高
圧噴射地盤攪拌混合改良工法を提案することを課題とす
る。The present invention has been made in view of the above problems, and does not discharge mud containing a hardening material to the ground as much as possible.
Moreover, an object of the present invention is to propose a high-pressure injection ground stirring and mixing improvement method capable of forming a hardened body having the planned dimensions.
【００１２】[0012]
【課題を解決するための手段】上記課題を解決した本発
明の請求項１記載の発明は、次の工程を含む、高圧液を
噴射し地盤を切削するとともに切削土砂と硬化材を混合
・攪拌し硬化体を造成することを特徴とする高圧噴射攪
拌混合地盤改良工法である。Means for Solving the Problems The invention according to claim 1 of the present invention, which has solved the above-mentioned problems, comprises the following steps: a step of injecting a high-pressure liquid to cut the ground, and mixing and stirring the cut soil and hardened material. This is a high-pressure injection-stirring / mixing ground improvement method characterized by forming a hardened body.
【００１３】（１）高圧液を噴射する核ノズルとこの核
ノズルの周囲から圧縮エアを噴射する包囲ノズルとを有
する高圧噴射ノズルを先端部に設けた注入管を地盤中に
挿入する工程。(1) A step of inserting, into the ground, an injection pipe provided with a high-pressure injection nozzle having a core nozzle for jetting a high-pressure liquid and a surrounding nozzle for jetting compressed air from around the core nozzle.
【００１４】（２）前記高圧噴射ノズルからエアを伴っ
た高圧液を側方に高圧噴射し、前記注入管を回転させな
がら地盤改良上限位置まで引き上げることによって、地
盤を切削するとともに、エアリフト効果により切削土砂
を地上に排出し、泥状の地盤改良予定領域を形成する工
程。(2) The high-pressure liquid with air is injected from the high-pressure injection nozzle to the side at a high pressure, and the injection pipe is rotated to raise the soil to the upper limit of the soil improvement. A process of discharging cutting earth and sand to the ground to form a muddy ground improvement area.
【００１５】（３）前記高圧噴射ノズルから高圧液の
み、またはエアを伴った高圧液を側方に高圧噴射させな
がら、前記注入管を地盤改良下限位置まで再度挿入する
ことによって、地盤改良予定領域を再切削および攪拌の
少なくとも一方を行う工程。(3) The injection pipe is reinserted to the ground improvement lower limit position while the high pressure liquid alone or the high pressure liquid accompanied by air is jetted from the high pressure injection nozzle to the side at a high pressure. Performing at least one of re-cutting and stirring.
【００１６】（４）前記注入管を引き上げながらその注
入管の先端部から液状の硬化材を噴射し、前工程で泥状
化した地盤改良予定領域の泥状物と硬化材を混合および
攪拌するとともに余剰の泥状物を地上に排出する工程。(4) A liquid hardening material is sprayed from the tip of the injection pipe while pulling up the injection pipe, and the hardened material and the muddy material in the ground improvement scheduled area which has been muddy in the previous process are mixed and stirred. Together with the process of discharging excess mud to the ground.
【００１７】請求項２記載の発明は、高圧噴射ノズル
は、高さ方向に複数有し、その上方のものは下方に向か
って噴射するようにし、下方のものは上方に向かって噴
射するようにした請求項１記載の高圧噴射攪拌混合地盤
改良工法である。[0017] According to a second aspect of the invention, including fluid morphism nozzle has a plurality in the height direction, its upper ones so as to inject I <br/> suited downward, those lower 2. The method of claim 1, wherein the injection is performed upward.
【００１８】[0018]
【発明の実施の形態】以下本発明を図面に示す実施の形
態によってさらに詳説する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the embodiments shown in the drawings.
【００１９】（１）削孔工程 本発明で使用する注入管１は、たとえば図５に示す注入
管１が用いられる。すなわち、注入管１は３流路管であ
り、中央に削孔水Ｗおよび硬化材Ｈ用流路２と高圧液Ｌ
用流路３と圧縮エアＡ用流路４の３流路を有し、その先
端部にはウイングビット等の削孔ビット５が取り付けら
れている。(1) Drilling Step As the injection pipe 1 used in the present invention, for example, the injection pipe 1 shown in FIG. 5 is used. That is, the injection pipe 1 is a three-flow pipe, and the drilling water W and the hardening material H flow path 2 and the high-pressure liquid L
There are three flow paths, i.e., a flow path 3 for compressed air and a flow path 4 for compressed air A, and a drill bit 5 such as a wing bit is attached to a tip end thereof.
【００２０】この削孔ビットには、削孔水Ｗを吐出させ
る吐出孔６が形成されている。この上部には、硬化材噴
射ノズル７が設けられている。この硬化材噴射ノズル７
と吐出孔６の流路方向の切替えは、注入管先端に内蔵さ
れた切替バルブ８により行われる。この切替えバルブ８
は、反発スプリング８Ａと基部側に付勢された弁座８Ｂ
とこの弁座８Ｂに向かって投入されるボール８Ｃとによ
り構成され、削孔水Ｗの供給時には、ボール８Ｃは投入
されていないので、供給される削孔水Ｗは、流路２を通
してそのまま吐出孔６から吐出される。硬化材Ｈの供給
に際しては、ボール８Ｃが投入され、その結果、切替え
バルブ８より先端側がボール８Ｃにより封止されるの
で、供給された硬化材Ｈは硬化材噴射ノズル７から噴出
されるようになる。The drill bit is provided with a discharge hole 6 for discharging drill water W. Above this, a hardener injection nozzle 7 is provided. This hardener injection nozzle 7
The switching of the flow direction of the discharge hole 6 and the discharge hole 6 is performed by a switching valve 8 built in the tip of the injection pipe. This switching valve 8
Is a resilient spring 8A and a valve seat 8B biased to the base side.
And the ball 8C to be thrown toward the valve seat 8B. When the drilling water W is supplied, since the ball 8C is not thrown, the supplied drilling water W is directly discharged through the flow path 2. Discharged from the hole 6. When the hardening material H is supplied, the ball 8C is thrown in, and as a result, the tip side of the switching valve 8 is sealed by the ball 8C, so that the supplied hardening material H is ejected from the hardening material injection nozzle 7. Become.
【００２１】さらに、硬化材噴射ノズル７の上方位置に
は高圧液Ｌ用流路３に連通した高圧液噴射用核ノズル９
Ａと、圧縮エア用流路４に連通し、前記核ノズル９Ａの
周囲を包囲しエアＡを噴射する包囲ノズル９Ｂとから構
成された、エアを伴う高圧液を側方に高圧噴射するため
の高圧噴射ノズル９が上下２ヶ所に相反する方向に噴射
するように設けられている。下部側の高圧噴射ノズル９
は所定角度斜め上向きに、一方、上部側の高圧噴射ノズ
ル９は所定角度斜め下向きに設けられている。Further, a high pressure liquid injection core nozzle 9 communicating with the high pressure liquid L flow path 3 is located above the hardening material injection nozzle 7.
A and a surrounding nozzle 9B which communicates with the compressed air flow path 4 and surrounds the core nozzle 9A and injects the air A. A high-pressure injection nozzle 9 is provided so as to inject in two opposite directions in opposite directions. Lower high-pressure injection nozzle 9
Is directed obliquely upward at a predetermined angle, while the upper high-pressure injection nozzle 9 is provided obliquely downward at a predetermined angle.
【００２２】さて、図１に示すように、かかる注入管１
を用い、ボーリングマシン等の削孔装置１０を用い、前
記注入管１先端の吐出孔６から削孔水Ｗを吐出させなが
ら地盤改良予定下限位置に、注入管１の先端部が到達す
るまで地盤を削孔し、この注入管１を所定位置に配置す
る。Now, as shown in FIG.
Using a drilling machine 10 such as a boring machine, while discharging drilling water W from the discharge hole 6 at the tip of the injection pipe 1, the ground is maintained until the tip of the injection pipe 1 reaches the ground improvement planned lower limit position. And the injection pipe 1 is arranged at a predetermined position.
【００２３】（２）一次切削工程 次いで、図２に示すように、地盤改良予定下限位置か
ら、高圧噴射ノズル９，９からエアを伴った高圧液を側
方に高圧噴射させつつ、注入管１を地盤改良上限位置ま
で回転させながら引き上げることによって地盤を切削す
るとともに、圧縮エアの同伴に伴うエアリフト効果によ
り切削土砂を地上に排出し、泥状の地盤改良予定領域を
形成する。(2) Primary Cutting Step Next, as shown in FIG. 2, the injection pipe 1 is injected from the high-pressure injection nozzles 9, 9 while the high-pressure liquid with air is injected from the lower limit of the ground improvement plan to the side. The ground is cut by rotating it up to the ground improvement upper limit position and cutting the ground, and the cut soil is discharged to the ground by the air lift effect accompanying the compressed air to form a muddy ground improvement scheduled area.
【００２４】この際使用する高圧液（切削水）Ｌとして
はこの切削工程で形成した泥状化領域の孔壁保持性およ
び硬化材注入工程時における置換性の点から、増粘剤が
添加された１００〜７５０ｍＰａ・ｓの範囲の粘度を有
するものが好適である。粘度が１００ｍＰａ・ｓより低
いと泥状化領域Ｚの孔壁が崩壊しやすくなり、また７５
０ｍＰａ・ｓより高くなると後工程での硬化材が目標域
に注入されず、上方に逸走して余剰泥状物と一緒に排出
されてしまう傾向が大きい。As the high-pressure liquid (cutting water) L used at this time, a thickener is used in view of the hole wall retention of the muddy region formed in this cutting step and the substitution property in the hardening material injection step. The added one having a viscosity in the range of 100 to 750 mPa · s is preferable. When the viscosity is lower than 100 mPa · s, the pore wall of the muddy zone Z is apt to collapse,
When the pressure is higher than 0 mPa · s, the hardening material in the post-process is not injected into the target area, but tends to run upward and be discharged together with the excess mud.
【００２５】この点については後述の実験例においてさ
らに説明する。ここで使用する増粘剤としてはセルロー
ス系、アクリル系、天然高分子系、繊維状鉱物系など種
々のものを使用することができる。This point will be further described in an experimental example described later. As the thickener used here, various types such as a cellulose type, an acrylic type, a natural polymer type, a fibrous mineral type and the like can be used.
【００２６】また、高圧液も噴射圧力は、この高圧液を
圧送する高圧ポンプ１１の元圧で約２００〜７００Ｋgf
／cm2 、一方、圧縮エアの圧力はエアを搬送するコンプ
レッサ１２の元圧で５〜１０Ｋｇｆ／cm2に設定するの
が好適である。The injection pressure of the high-pressure liquid is about 200 to 700 kgf at the original pressure of the high-pressure pump 11 for pumping the high-pressure liquid.
/ Cm 2, on the other hand, the pressure of the compressed air is preferably set to 5 to 10 kgf / cm 2 as the original pressure of the compressor 12 for conveying the air.
【００２７】地上部に排出された切削液と土砂の混合物
からなる排泥Ｍは、排泥ポンプ装置１３によりピットか
ら脱水装置（図示せず）に送り込んで、土砂分と液状分
とに分離し、分離した液状分はさらに凝集処理等を施
し、切削液や削孔水として再利用するのが望ましい。切
削工程で排出される泥状物には硬化材がほとんど含まれ
ていないため、再利用のための処理がしやすい。一方、
分離した土砂分はダンプトラック等で搬出し適正に処分
する。The sludge M, which is a mixture of cutting fluid and earth and sand discharged to the ground, is sent from the pit to a dewatering device (not shown) by a sludge pump 13 to be separated into earth and sand and liquid. It is preferable that the separated liquid is subjected to a coagulation treatment or the like and reused as a cutting fluid or drilling water. Since the hard material is hardly contained in the mud discharged in the cutting process, it can be easily processed for reuse. on the other hand,
The separated sediment should be carried out by dump trucks and disposed of properly.
【００２８】（３）二次切削・攪拌工程 次いで、図３に示すように、高圧噴射ノズル９，９から
高圧液またはエアを伴った高圧液を側方に高圧噴射させ
ながら、注入管１を地盤改良下限位置まで再度挿入する
ことによって、地盤改良予定領域を再切削及び／又は攪
拌する。(3) Secondary Cutting and Stirring Step Next, as shown in FIG. 3, the injection pipe 1 is ejected from the high-pressure injection nozzles 9 and 9 while the high-pressure liquid or the high-pressure liquid with air is injected to the side at high pressure. By re-inserting to the ground improvement lower limit position, the ground improvement scheduled area is re-cut and / or agitated.
【００２９】このように再度、注入管１を下降させなが
ら高圧液等を噴射することによって、地盤改良予定領域
の孔壁崩壊や該領域中の土砂粒子の沈降によりその下端
に滞積した土砂分を攪乱し、滞積した土砂を再度、地盤
改良予定領域中に浮遊または分散させる。[0029] As thus again, by injecting lowered long <br/> et pressure liquid such as an injection tube 1, by settling of sediment particles in the pore walls collapse and the region of ground improvement plan area The sediment accumulated at the lower end is disturbed, and the accumulated sediment is suspended or dispersed again in the ground improvement area.
【００３０】二次切削・攪拌の目的は地盤の切削という
よりも地盤改良予定領域を再攪拌し、下端に滞積した土
砂を地盤改良予定領域中に再浮遊または再分散させるこ
とにあるため、噴射圧力は一次切削時よりも低く設定し
てもよい。The purpose of the secondary cutting / stirring is not to cut the ground, but to re-stir the ground improvement area and re-suspend or re-disperse the sediment accumulated at the lower end in the ground improvement area. The injection pressure may be set lower than at the time of primary cutting.
【００３１】また、上記のように滞積した土砂を再浮遊
または再分散するのに、地盤改良予定領域の全長に渡っ
て行う必要のない場合には、下限付近のみ二次切削・攪
拌を行うこともある。When it is not necessary to re-suspend or re-disperse the accumulated soil as described above over the entire length of the ground improvement scheduled area, secondary cutting and stirring are performed only near the lower limit. Sometimes.
【００３２】また、一次切削で形成した地盤改良予定領
域の杭径を何らかの方法により測定し、杭径が不十分な
ことが判明している場合には、その部分に再度高圧液を
噴射し、所定の径になるように切削することもできる。Further, the diameter of the pile in the ground improvement planned area formed by the primary cutting is measured by any method, and when it is found that the pile diameter is insufficient, the high-pressure liquid is injected again to that part, It can also be cut to a predetermined diameter.
【００３３】（４）硬化材噴射工程 次に、図４に示すように、注入管１を順次引き上げなが
ら、グラウトポンプ１４により硬化材Ｈを注入管１内に
送り込んで、その先端付近の硬化材噴射ノズル７からス
ラリー状の硬化材Ｈを噴射し、泥状化領域Ｚの泥状物と
硬化材Ｈを混合するとともに余剰の泥状物を地上に排出
して地盤中に硬化体を造成する。(4) Curing Material Injection Step Next, as shown in FIG. 4, the grout pump 14 feeds the hardening material H into the filling tube 1 while sequentially pulling up the filling tube 1, and the hardening material near the tip thereof. The slurry-like hardening material H is sprayed from the spray nozzle 7 to mix the muddy material in the muddy region Z and the hardening material H, and discharge excess muddy material to the ground to form a hardened material in the ground. .
【００３４】この硬化材としては、注入した硬化材を目
標域に確実に注入させ、上方に逸走するのを防ぐため
に、水／セメント比１００％のセメントスラリーに対
し、増粘剤の添加された１５０〜２０００ｍＰａ・ｓの
範囲の粘度を呈するものを使用し、特に２５０〜５００
ｍＰａ・ｓの粘度を呈するものが好適である。As this hardening material, a thickener was added to a cement slurry having a water / cement ratio of 100% in order to ensure that the injected hardening material was injected into the target area and to prevent upward runaway. Use a material exhibiting a viscosity in the range of 150 to 2000 mPa · s, particularly 250 to 500
Those exhibiting a viscosity of mPa · s are preferred.
【００３５】粘度が１５０ｍＰａ・ｓより低いと、泥状
化領域中に注入した硬化材が上方に逸走しやすく、硬化
材混じりの泥状物が排出されてしまう。一方、１５００
ｍＰａ・ｓより高くすると、使用する増粘剤の添加量が
過剰となりコスト高になるとともに粘性が高すぎて硬化
材の圧送ラインで閉塞トラブルが発生しやすくなる。ま
た、ここで使用する増粘剤としてはセルロース系、アク
リル系、天然高分子系、繊維状鉱物系など種々のものを
使用することができる。If the viscosity is lower than 150 mPa · s, the hardened material injected into the muddy region easily escapes upward, and the mud mixed with the hardened material is discharged. On the other hand, 1500
If the pressure is higher than mPa · s, the amount of the thickener used is excessive and the cost is increased. In addition, the viscosity is too high, so that a blockage trouble easily occurs in the pressure feed line of the hardening material. In addition, as the thickener used here, various types such as a cellulose type, an acrylic type, a natural polymer type, and a fibrous mineral type can be used.
【００３６】硬化材の吐出圧力は、グラウトポンプ１４
の元圧で２０〜２００Ｋｇｆ／cm2にするのが好適であ
り、切削工程での高圧液の吐出圧力よりかなり低圧力に
設定される。The discharge pressure of the hardening material is controlled by the grout pump 14.
The source pressure is preferably 20 to 200 kgf / cm 2 , and is set to a pressure considerably lower than the discharge pressure of the high-pressure liquid in the cutting process.
【００３７】[0037]
【実施例】図１〜図４に示す工程をもって、図５に示す
注入管を用いて砂質地盤を対象に本発明の実験を行っ
た。EXAMPLE An experiment of the present invention was conducted on the sandy ground using the injection pipe shown in FIG. 5 in the steps shown in FIGS.
【００３８】すなわち、注入管を砂質地盤中に建て込み
注入管の核ノズルから清水（切削水）を４００Ｋｇｆ／
cm2の圧力で噴射し、包囲ノズルから圧縮空気を１０Ｋ
ｇｆ／cm2の圧力を噴射することにより切削工程を実施
した。That is, the injection pipe is erected in the sandy ground, and fresh water (cutting water) is supplied from the core nozzle of the injection pipe at 400 kgf / cut.
Inject with a pressure of 2 cm2, and pressurized air from surrounding nozzle at 10K
The cutting step was performed by injecting a pressure of gf / cm 2 .
【００３９】次いで切削工程で形成した泥状化領域中に
再度注入管を回転させながら最下端まで建て込むと同時
に、核ノズルから清水（高圧液）を１５０Ｋｇｆ／cm2
の圧力で噴射するとともに、包囲ノズルから圧縮空気を
１０Ｋｇｆ／cm2の圧力で噴射することによって泥状化
領域を再攪拌（二次切削・攪拌）し、次いで注入管を回
転させながら硬化材噴射ノズルから水／セメント比１０
０％のセメントスラリー（硬化材）を５０Ｋｇｆ／cm2
の圧力で吐出させ、改良上限位置まで注入管を順次引き
上げることによって硬化材注入工程を実施し、硬化体
（直径約２，４００m、長さ１０m）の造成を行った。切
削工程では切削水の吐出量を２５０リットル／ｍｉｎ、
引き上げ速度を１５秒／ピッチ（１ピッチ＝２５mm）に
設定し、二次切削・攪拌工程では高圧液の吐出量は１５
０リットル／ｍｉｎ、引き上げ速度を５秒／ピッチ、硬
化材注入工程では硬化材の吐出量を２００リットル／ｍ
ｉｎ、引き上げ速度を３０秒／ピッチに設定し実施し
た。Next, at the same time as the injection pipe is rotated to the lowermost end in the muddy region formed in the cutting step while rotating the injection pipe, 150 kgf / cm 2 of fresh water (high-pressure liquid) is supplied from the core nozzle.
At the same time, and the compressed air is injected from the surrounding nozzle at a pressure of 10 kgf / cm 2 to re-stir the muddy region (secondary cutting / stirring), and then inject the hardened material while rotating the injection pipe. Water / cement ratio 10 from nozzle
0% cement slurry (hardening material) is applied to 50 kgf / cm 2
, And the hardening material injection step was performed by sequentially pulling up the injection pipe to the improved upper limit position, thereby forming a hardened body (about 2,400 m in diameter and 10 m in length). In the cutting process, the discharge rate of cutting water is 250 liter / min,
The lifting speed was set to 15 seconds / pitch (1 pitch = 25 mm), and the discharge amount of the high-pressure liquid was 15 in the secondary cutting / stirring process.
0 liter / min, lifting speed 5 seconds / pitch, and in the curing material injection step, the discharge amount of the curing material was 200 liter / m.
in, the lifting speed was set to 30 seconds / pitch.
【００４０】この際、硬化材注入工程において地上に排
出される泥状物のＰＨ値を測定したところ８．６以下の
値を示し、また目視でもセメント分の排出は確認され
ず、硬化材注入工程においてセメント分はほとんど排出
されないという良好な結果が得られた。At this time, when the PH value of the mud discharged to the ground in the hardening material injection step was measured, it showed a value of 8.6 or less, and no discharge of cement was confirmed by visual inspection. Good results were obtained in which almost no cement was discharged during the process.
【００４１】さらに、造成数日後、地盤から硬化体を掘
り出し出来形の確認をしたところ、硬化体の下端部分に
おいても所定寸法の杭径が確保され、また採取したコア
サンプルの圧縮強度も８３Ｋｇｆ／cm2と十分な強度を
有しており、未固結部分のない、寸法通りの硬化体が造
成できたことが確認された。Further, a few days after the formation, the hardened body was dug out from the ground and confirmed to be formed. As a result, a pile diameter of a predetermined size was secured at the lower end of the hardened body, and the compressive strength of the collected core sample was also 83 kgf / kg. It was confirmed that the cured product had a sufficient strength of cm 2, and had no unconsolidated portion, and could be formed according to dimensions.
【００４２】[0042]
【発明の効果】以上のとおり、本発明によれば、泥状の
地盤改良予定領域を高圧液によって二次切削・攪拌し、
その直後に硬化材の注入を開始するため、土砂分が浮遊
又は分散している状態の地盤改良予定領域に硬化材が噴
射されることとなり、噴射した硬化材は目標領域に正確
に注入され、かつその領域の泥状物と確実に混合攪拌さ
れる。その結果、未固結部分が生じたり、杭径が細まる
ことがなく、計画寸法通りの硬化体を造成することがで
きる。As described above, according to the present invention, the muddy ground improvement area is secondarily cut and agitated by high-pressure liquid,
Immediately after that, to start the injection of the hardening material, the hardening material will be injected into the ground improvement scheduled area where the soil and sand are floating or dispersed, and the injected hardening material is accurately injected into the target area, And, it is surely mixed and stirred with the mud in the region. As a result, an unconsolidated portion does not occur and the pile diameter does not decrease, and a hardened body having the planned dimensions can be formed.
【００４３】また、上述の通り、噴射した硬化材が目標
領域に確実に注入されるので、予め計画した硬化材の注
入・充填速度と、注入・充填した硬化材と泥状化物の置
換速度との均衡が保たれる。よって、硬化材が上方に逸
走し、余剰の泥状物と一緒に地上に排出されるのを防止
することができる。Further, as described above, the injected hardening material is reliably injected into the target area, so that the injection speed and the filling speed of the hardening material planned in advance and the replacement speed of the injected hardening material and the muddy material are reduced. Is balanced. Therefore, it is possible to prevent the hardened material from escaping upward and being discharged to the ground together with the excess mud.
【図面の簡単な説明】[Brief description of the drawings]
【図１】本発明の第１工程の説明図である。FIG. 1 is an explanatory view of a first step of the present invention.
【図２】本発明の第２工程の説明図である。FIG. 2 is an explanatory view of a second step of the present invention.
【図３】本発明の第３工程の説明図である。FIG. 3 is an explanatory view of a third step of the present invention.
【図４】本発明の第４工程の説明図である。FIG. 4 is an explanatory view of a fourth step of the present invention.
【図５】注入管例の縦断面図である。FIG. 5 is a longitudinal sectional view of an example of an injection tube.
【符号の説明】 １…注入管、２…削孔水硬化材用流路、３…高圧液用流
路、４…圧縮エア用流路４、５…削孔ビット、６…吐出
孔、７…硬化材噴射ノズル、８…切替えバルブ、９…高
圧噴射ノズル。[Description of Reference Numerals] 1 ... injection tube, 2 ... drilling water curable material passage, 3 ... high pressure liquid flow path, 4 ... channel 4,5 ... bit boring for compressed air, 6 ... discharge hole, 7 ... hardening material injection nozzle, 8 ... switching valve, 9 ... high pressure injection nozzle.
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 2D040 AA01 AB03 AC02 BA01 BA02 BB01 BD05 CA01 CA10 CB03 CD01 DA03 DA07 DA12 DA16 DB04 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D040 AA01 AB03 AC02 BA01 BA02 BB01 BD05 CA01 CA10 CB03 CD01 DA03 DA07 DA12 DA16 DB04
Claims (2)
削するとともに切削土砂と硬化材を混合・攪拌し硬化体
を造成することを特徴とする高圧噴射攪拌混合地盤改良
工法。 （１）高圧液を噴射する核ノズルとこの核ノズルの周囲
から圧縮エアを噴射する包囲ノズルとを有する高圧噴射
ノズルを先端部に設けた注入管を地盤中に挿入する工
程。 （２）前記高圧噴射ノズルからエアを伴った高圧液を側
方に高圧噴射し、前記注入管を回転させながら地盤改良
上限位置まで引き上げることによって、地盤を切削する
とともに、エアリフト効果により切削土砂を地上に排出
し、泥状の地盤改良予定領域を形成する工程。 （３）前記高圧噴射ノズルから高圧液のみ、またはエア
を伴った高圧液を側方に高圧噴射させながら、前記注入
管を地盤改良下限位置まで再度挿入することによって、
地盤改良予定領域を再切削および攪拌の少なくとも一方
を行う工程。 （４）前記注入管を引き上げながらその注入管の先端部
から液状の硬化材を噴射し、前工程で泥状化した地盤改
良予定領域の泥状物と硬化材を混合および攪拌するとと
もに余剰の泥状物を地上に排出する工程。1. A high-pressure jet-stirred-mixed ground improvement method, comprising the following steps: jetting a high-pressure liquid to cut the ground, and mixing and stirring the cut soil and hardening material to form a hardened body. (1) A step of inserting, into the ground, an injection pipe provided with a high-pressure injection nozzle having a core nozzle for injecting a high-pressure liquid and a surrounding nozzle for injecting compressed air from around the core nozzle at the tip end. (2) The high-pressure liquid with air is injected from the high-pressure injection nozzle to the side at a high pressure, and the injection pipe is rotated to raise the soil to the upper limit of the soil improvement. The process of discharging to the ground and forming a muddy ground improvement area. (3) By re-inserting the injection pipe to the ground improvement lower limit position while injecting only high-pressure liquid or high-pressure liquid with air from the high-pressure injection nozzle to the side at high pressure,
A step of performing at least one of re-cutting and stirring of the ground improvement scheduled area. (4) While raising the injection pipe, a liquid hardening material is sprayed from the tip of the injection pipe to mix and agitate the hardening material with the muddy material in the soil improvement scheduled area which has been muddyed in the previous step, and to mix and stir the excess. The process of discharging mud to the ground.
し、その上方のものは下方の向かって噴射するように
し、下方のものは上方に向かって噴射するようにした請
求項１記載の高圧噴射攪拌混合地盤改良工法。2. A high-pressure liquid injection nozzle having a plurality of nozzles in a height direction, wherein an upper nozzle jets downward and a lower nozzle jets upward. High-pressure injection mixing ground improvement method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22571098A JP3264887B2 (en) | 1998-08-10 | 1998-08-10 | High-pressure injection mixing ground improvement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22571098A JP3264887B2 (en) | 1998-08-10 | 1998-08-10 | High-pressure injection mixing ground improvement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000054368A true JP2000054368A (en) | 2000-02-22 |
| JP3264887B2 JP3264887B2 (en) | 2002-03-11 |
Family
ID=16833599
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22571098A Expired - Fee Related JP3264887B2 (en) | 1998-08-10 | 1998-08-10 | High-pressure injection mixing ground improvement method |
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| Country | Link |
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