JPH07158044A - Sand ground liquefaction preventing work method - Google Patents
Sand ground liquefaction preventing work methodInfo
- Publication number
- JPH07158044A JPH07158044A JP30894893A JP30894893A JPH07158044A JP H07158044 A JPH07158044 A JP H07158044A JP 30894893 A JP30894893 A JP 30894893A JP 30894893 A JP30894893 A JP 30894893A JP H07158044 A JPH07158044 A JP H07158044A
- Authority
- JP
- Japan
- Prior art keywords
- casing pipe
- crushed stone
- ground
- net bag
- sand
- 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
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は砂地盤の液状化防止のた
めに、地下水排出用の砕石柱を形設する工法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a crushed stone column for discharging groundwater in order to prevent liquefaction of sand ground.
【０００２】[0002]
【従来の技術】近年、大地震により地盤中の地下水の水
圧が急上昇し、剪断抵抗が失われて砂が流動化するとい
う砂地盤の液状化現象に関心が寄せられるようになって
きている。このような液状化に対する事前対策として
は、砂地盤を締め固めて地盤の間隙率の低減および剪断
強さの向上を図る方法、地盤中に砂杭あるいは砕石柱を
形設して高圧地下水の排水促進を図る方法、地盤中に水
ガラス系その他の薬剤を注入する等して地盤の固化を図
る方法あるいは地盤中にディープウェルと止水壁を設け
てポンプ排水によって地下水水位の低下を図る方法等が
あり、それぞれ地盤、環境、その他の条件に応じて得失
がある。2. Description of the Related Art In recent years, there has been a growing interest in the liquefaction phenomenon of sand ground, in which groundwater pressure in the ground rises sharply due to a large earthquake, shear resistance is lost, and sand is fluidized. Preliminary measures against such liquefaction include a method of compacting the sand ground to reduce the porosity of the ground and improving the shear strength, drainage of high-pressure groundwater by forming sand piles or crushed stone columns in the ground. Method of promoting, method of solidifying the ground by injecting water glass or other chemicals into the ground, or method of lowering the groundwater level by pump drainage by providing deep well and water blocking wall in the ground, etc. There are advantages and disadvantages depending on the ground, environment, and other conditions.
【０００３】このうち、特に一般的に用いられてきた工
法としては、締め固め方法におけるサンドコンパクショ
ン工法および排水促進方法におけるグラベル（砕石）ド
レーン工法があげられる。前者は、振動ハンマーを備え
るケーシングパイプを地盤中に圧入し、このケーシング
パイプを通して地盤中に砂粒を供給し、この砂粒を振動
により締め固めながら、ケーシングパイプを引き抜いて
行くという工法であり、後者は、略全長に亘ってスクリ
ューを周設したケーシングパイプを用い、回転駆動によ
って地盤中に貫入させ、砕石を投入しながらこのケーシ
ングパイプを引き抜き、地盤中に排水用の砕石柱を形設
するという工法である。Among these, particularly commonly used methods include a sand compaction method in the compaction method and a gravel (crushed stone) drain method in the drainage promotion method. The former is a method of press-fitting a casing pipe equipped with a vibration hammer into the ground, supplying sand grains into the ground through this casing pipe, and then pulling out the casing pipe while compacting the sand grains by vibration. , A method of forming a crushed stone column for drainage in the ground by using a casing pipe in which a screw is installed over almost the entire length, making it penetrate into the ground by rotational driving, pulling out this casing pipe while charging crushed stones Is.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、前者の
サンドコンパクション工法は、施工時間が長く、特に、
施工において、振動機を使用するので、振動や騒音が発
生し、また、周辺地盤に変状を伴うこともあるので、市
街地や既設工場域等での採用は難しいという問題があ
り、後者のグラベルドレーン工法においては、振動や騒
音は抑えられるが、形設される砕石柱が土圧によって狭
窄化し、また切断する等の機能低下を来すのを避けるた
め、柱径を４００〜５００ｍｍというような太いものに
しており、従って、使用砕石も多く、また、施工機械が
大きいものとなり、例えば、既設のタンク域や市街地等
比較的狭隘な土地では施工が難しく、さらに、ケーシン
グパイプによる排出残土量が多く、その処理費用が嵩む
という問題があった。However, the former sand compaction method requires a long construction time,
Since a vibration machine is used in the construction, vibration and noise may occur, and the surrounding ground may be deformed.Therefore, there is a problem that it is difficult to adopt it in urban areas or existing factory areas. In the drainage method, vibration and noise can be suppressed, but in order to avoid that the crushed stone pillar to be formed is constricted due to earth pressure, and that it causes functional deterioration such as cutting, the pillar diameter is 400-500 mm. Since it is thick, it requires a large amount of crushed stones and a large construction machine.For example, it is difficult to construct on a relatively small land such as an existing tank area or urban area. In many cases, there has been a problem that the processing cost increases.
【０００５】本発明は、以上の状況に鑑み、いわゆる小
回りの利く比較的小さい機械で施工でき、従って、既設
タンク域等での施工も容易で、また、施工に当たっては
振動や騒音を発生せず、施工能率がよく、さらに、殆ど
排出残土を生ぜず、大地震に際しては過剰間隙水圧を着
実に消散できるという経済的効果の大きい排水促進法に
おける砂地盤の液状化防止工程の提供を目的とするもの
である。In view of the above situation, the present invention can be carried out by a so-called relatively small machine with a small turning ability, and therefore can be easily installed in an existing tank area or the like, and no vibration or noise is generated during the installation. The purpose is to provide a liquefaction prevention process for the sand ground in the drainage promotion method, which has a high economic effect that it has good construction efficiency, produces almost no discharged soil, and can steadily dissipate excess pore water pressure in the event of a large earthquake. It is a thing.
【０００６】[0006]
【課題を解決するための手段】上記の目的を達成するた
め、本発明は、先端部外周にスクリューを形成した内径
１５０ｍｍ以下のケーシングパイプを地盤に回転圧入し
た後、該ケーシングパイプ内に合成樹脂製の網袋を挿入
し、該網袋内に砕石を充填して地盤上に至る砕石柱を形
設し、次いで、前記ケーシングパイプを抜き出し、前記
砕石柱の頭部を地盤上に敷装する砂又は砕石マットと一
体化させる砂地盤の液状化防止工法を、また、前記ケー
シングパイプの回転圧入を該ケーシングパイプ内に給水
しながら行う砂地盤の液状化防止工法を、またさらに、
前記砕石の充填を前記ケーシングパイプ内に給水しなが
ら行う砂地盤の液状化防止工法を、またさらに、前記砕
石は５〜１３ｍｍの粒度を主体としたものであるところ
の砂地盤の液状化防止工法を提案するものである。In order to achieve the above-mentioned object, the present invention is to provide a casing with a screw formed on the outer circumference of a tip end with a casing pipe having an inner diameter of 150 mm or less by rotationally press-fitting it into the ground, and then making a synthetic resin inside the casing pipe. Insert a net bag made of crushed stone, fill the net bag with crushed stone to form a crushed stone column reaching the ground, then pull out the casing pipe and lay the head of the crushed stone column on the ground Liquefaction prevention construction method of the sand ground to be integrated with sand or crushed stone mat, also, the liquefaction prevention construction method of the sand ground performed while water is rotationally press-fitted into the casing pipe,
A method for preventing liquefaction of sand ground, which is carried out while filling the casing pipe with water, and a method for preventing liquefaction of sand ground, wherein the crushed stone is mainly composed of particles having a particle size of 5 to 13 mm. Is proposed.
【０００７】[0007]
【作用】ケーシングパイプを、地盤上に垂直に保持した
後、先端に使い捨ての底蓋を施してケーシングパイプを
回転させることによって地盤中に貫入する。ケーシング
パイプが所定深さまで貫入したら、回転を止め、このケ
ーシングパイプ内に網袋を挿入保持し、網袋内に砕石を
投入して充填し、地盤上まで砕石柱を形設させる。次い
で、ケーシングパイプを逆回転させて引き抜いて砕石柱
を残し、この砕石柱の頭部を地盤上に敷装する砂マット
または砕石マットを一体化させることにより、大地震時
に発生する地盤中の高圧間隙水は前記砕石柱内を上昇
し、砂マットまたは砕石マットを浸透して地表面上に導
出されるので、砂地盤の液状化を防止することができ
る。After the casing pipe is held vertically on the ground, a disposable bottom lid is attached to the tip and the casing pipe is rotated to penetrate into the ground. When the casing pipe penetrates to a predetermined depth, the rotation is stopped, the net bag is inserted and held in the casing pipe, and crushed stones are put into the net bag to fill the crushed stone pillars to the ground. Then, reversely rotate the casing pipe and pull out to leave a crushed stone column, and by integrating the sand mat or crushed stone mat that lays the head of this crushed stone column on the ground, high pressure in the ground generated during a large earthquake Since the pore water rises in the crushed stone pillar and permeates the sand mat or crushed stone mat and is discharged onto the ground surface, liquefaction of the sand ground can be prevented.
【０００８】ケーシングパイプの回転圧入時、このケー
シングパイプ内に給水を行うことにより、地下水の噴き
上げや土圧の影響を抑え、ケーシングパイプ先端のずれ
を防止することができる。網袋内への砕石の充填時、ケ
ーシングパイプ内に給水を行うことにより、地下水の噴
き上げを抑え、砕石の引っ掛かりを低減して砕石の円滑
な充填を行うことができる。砕石の粒度を５〜１３ｍｍ
を主体とするものとすることにより、網袋内の充填性が
よく、小土粒子による目詰まりがなく透水性のよい砕石
柱が得られる。By supplying water into the casing pipe when the casing pipe is rotationally press-fitted, it is possible to suppress the influence of the spouting of groundwater and the earth pressure and prevent the displacement of the casing pipe tip. By supplying water into the casing pipe when filling the crushed stones into the net bag, it is possible to prevent the groundwater from being blown up, reduce the catch of the crushed stones, and smoothly fill the crushed stones. Particle size of crushed stone is 5 to 13 mm
By mainly using, it is possible to obtain a crushed stone column which has a good filling property in the net bag, is not clogged with small soil particles, and has good water permeability.
【０００９】[0009]
【実施例】以下、実施例による図面によって本発明の液
状化防止工法を説明する。図１は本発明の工法の実施状
況を示す施工装置の要部側面図で、図２は本発明の工法
を実施する図１の施工装置の側面図で、図３および図４
は本発明の工法の実施工程を示す略側面図である。The liquefaction prevention method of the present invention will be described below with reference to the drawings of the embodiments. FIG. 1 is a side view of a main part of a construction apparatus showing a state of implementation of the construction method of the present invention, FIG. 2 is a side view of the construction apparatus of FIG. 1 for implementing the construction method of the present invention, and FIGS.
[Fig. 3] is a schematic side view showing an implementation step of the method of the present invention.
【００１０】本発明工法の施工装置Ａは、図２に示すよ
うに、クローラ走行車からなる装置本体１と、この装置
本体１によって地盤２に対して垂直に保持される長尺の
リーダ３と、このリーダ３に昇降動可能に取り付けられ
る回転駆動装置４と、この回転駆動装置４によって回転
可能に上部を保持されると共に、前記リーダ３に固定さ
れた下部ガイド５をガイドとして昇降動可能にされた鋼
製長尺のケーシングパイプ６と、このケーシングパイプ
６の直上にロードセル７を備えた吊り具８でもって懸吊
可能に配設された砕石用のホッパー９とから成ってい
る。As shown in FIG. 2, the construction apparatus A of the construction method of the present invention comprises an apparatus main body 1 composed of a crawler traveling vehicle, and a long leader 3 held vertically by the apparatus main body 1 with respect to the ground 2. A rotary drive device 4 attached to the reader 3 so as to be movable up and down, and an upper part rotatably held by the rotary drive device 4 and capable of moving up and down using a lower guide 5 fixed to the reader 3 as a guide. A long steel casing pipe 6 and a hopper 9 for crushing stones, which is suspended above the casing pipe 6 by a suspender 8 having a load cell 7 so as to be suspended.
【００１１】ケーシングパイプ６は、１５０ｍｍ以下の
小内径をなし、図１に示すように、先端にビットとして
爪１０を付すと共に先端部にはスクリュー１１を周設し
てあり、ケーシングパイプ６の先端開口に鉄板による使
い捨ての底蓋１２を施し、回転駆動装置４により回転さ
せることにより、地盤２中に圧入する形で貫入させるこ
とができるようにしてある。この実施例におけるケーシ
ングパイプ６は、内径１２０ｍｍで径が細く、また、全
長約１５ｍに対して先端部のスクリュー１１を施した部
分の長さは２〜３ｍという短いものにしてあり、従来の
略全長に亘ってスクリューが周設されたグラベルドレー
ン工法におけるケーシングパイプとは異なり、掘削では
なく、圧入の形をとるので、貫入に際して排出残土は殆
ど生じない。The casing pipe 6 has a small inner diameter of 150 mm or less. As shown in FIG. 1, a tip is provided with a claw 10 as a bit, and a screw 11 is provided around the tip, so that the casing pipe 6 has a tip. The opening is provided with a disposable bottom lid 12 made of an iron plate and is rotated by the rotation drive device 4 so that the bottom lid 12 can be inserted into the ground 2 in a press-fitted manner. The casing pipe 6 in this embodiment has an inner diameter of 120 mm and a small diameter, and the length of the distal end portion provided with the screw 11 is about 2 to 3 m with respect to the total length of about 15 m. Unlike the casing pipe in the gravel drain method in which the screw is installed over the entire length, it is in the form of press-fitting rather than excavation, so almost no residual soil is discharged during penetration.
【００１２】ケーシングパイプ６の直上には回転駆動装
置４によりホッパー受け台１３を支持させてあり、ホッ
パー９は、このホッパー受け台１３上に載置された状態
でトラクタショベル１４からの砕石１５を受けるように
されている。また、ホッパー９の投入口は筒状部９ａに
形成して砕石１５の投入を規制するシャッタ１６を設け
てある。A hopper cradle 13 is supported by a rotary drive device 4 just above the casing pipe 6, and a hopper 9 is mounted on the hopper cradle 13 to crush stones 15 from a tractor shovel 14. I am supposed to receive it. In addition, a shutter 16 is provided at the input port of the hopper 9 in the cylindrical portion 9a to regulate the input of the crushed stone 15.
【００１３】地盤２中に所定の深さまで貫入されたケー
シングパイプ６には網袋１７を挿入する。この網袋１７
は、引張り強度の大きいポリエチレン原糸により強靱に
編み込まれ、ケーシングパイプ６への挿入時、その上端
は前記ホッパー９の筒状部９ａにバンドで取り付けるよ
うにしてある。また、後記するように、ケーシングパイ
プ６の貫入時および砕石１５の投入時に給水を行うため
に、ケーシングパイプ６の上部開口には給水管１８を臨
ませるようにしてあり、さらにまた、後記するように、
ケーシングパイプ６の引き抜き時にケーシングパイプ６
内に圧縮空気の吹き込みを行うために、圧縮空気管１９
を接続した上蓋２０（図４（ｂ））を上部開口に取り付
けできるようにしてある。A net bag 17 is inserted into the casing pipe 6 which has penetrated into the ground 2 to a predetermined depth. This net bag 17
Is tightly knitted with a polyethylene raw yarn having a high tensile strength, and the upper end thereof is attached to the tubular portion 9a of the hopper 9 with a band when it is inserted into the casing pipe 6. Further, as will be described later, in order to supply water when the casing pipe 6 penetrates and when the crushed stones 15 are fed, a water supply pipe 18 is made to face the upper opening of the casing pipe 6, and as will be described later. To
When pulling out the casing pipe 6, the casing pipe 6
In order to blow compressed air into the compressed air pipe 19
The upper lid 20 (Fig. 4 (b)) connected to the above can be attached to the upper opening.
【００１４】次に、この施工装置Ａによる本発明工法の
施工工程を、図３および図４によって説明する。施工開
始時には、装置本体１を動かして、図３（ａ）に示すよ
うに、ケーシングパイプ６を所定位置において垂直姿勢
となるようにセットし、ケーシングパイプ６の先端には
底蓋１２として鉄板を敷く。Next, the construction process of the construction method of the present invention using the construction apparatus A will be described with reference to FIGS. 3 and 4. At the start of construction, the apparatus body 1 is moved to set the casing pipe 6 in a vertical position at a predetermined position as shown in FIG. 3 (a), and an iron plate serving as a bottom lid 12 is provided at the tip of the casing pipe 6. Lay.
【００１５】次いで、図３（ｂ）に示すように、回転駆
動装置４による減速回転駆動によってケーシングパイプ
６を回転させることにより、地盤２にケーシングパイプ
６を貫入させる。この貫入時、ケーシングパイプ６の上
部開口に給水管１８を臨ませて給水を行う。この給水
は、貫入時における地下水の噴き上げや土圧によるケー
シングパイプ６のずれを防ぐのに有用である。Next, as shown in FIG. 3 (b), the casing pipe 6 is inserted into the ground 2 by rotating the casing pipe 6 by decelerating rotation drive by the rotary drive device 4. At the time of this penetration, water is supplied by making the water supply pipe 18 face the upper opening of the casing pipe 6. This water supply is useful for preventing the displacement of the casing pipe 6 due to the spouting of groundwater and the earth pressure at the time of intrusion.
【００１６】所定深さまでケーシングパイプ６が貫入さ
れたら、回転を止め、図３（ｃ）のように、上部開口よ
り所定長さの網袋１７を挿入する。この挿入は、網袋１
７の先端に錘として少量の砕石１５を入れてケーシング
パイプ６内に投入する形で行う。網袋１７の上端部はホ
ッパー９の筒状部９ａにバンドで止め着ける。When the casing pipe 6 is penetrated to a predetermined depth, the rotation is stopped and a net bag 17 of a predetermined length is inserted from the upper opening as shown in FIG. 3 (c). This insertion is a mesh bag 1
A small amount of crushed stone 15 as a weight is put at the tip of 7 and put into the casing pipe 6. The upper end of the net bag 17 can be fastened to the tubular portion 9a of the hopper 9 with a band.
【００１７】網袋１７の挿入が終了し、図４（ａ）のよ
うにホッパー９の筒状部９ａに取り付けた後、トラクタ
ショベル１４により砕石１５をホッパー９内に投入し、
網袋１７内に充填する。砕石１５は、６号乃至７号の５
〜１３ｍｍを主体とする粒度のものが、充填性および透
水性の点から好ましい。５ｍｍ以下のものでは砕石柱と
して透水性が悪く、１３ｍｍ以上のものでは小土粒子の
混入により目詰まりを生じ易い。また、この砕石の充填
時、ケーシングパイプ６の上部開口に給水管１８を臨ま
せて給水を行うことにより、地下水の噴き上げを抑え、
また砕石同士の搦みを低減し、砕石の投入充填を抵抗な
く円滑に行うことができる。網袋１７の上端まで砕石１
５が充填されたら、シャッタ１６により投入を停止し、
次いで、吊り具８により充填された網袋１７ごとにホッ
パー９を吊り上げ、ロードセル７によって計量を行い、
砕石１５の充填を確認する。After the net bag 17 has been inserted and attached to the tubular portion 9a of the hopper 9 as shown in FIG. 4 (a), the crushed stone 15 is put into the hopper 9 by the tractor shovel 14.
The net bag 17 is filled. Crushed stone 15 is No. 6 to No. 7
Particles having a particle size of ˜13 mm as a main component are preferable from the viewpoint of filling property and water permeability. If it is 5 mm or less, the water permeability as a crushed stone column is poor, and if it is 13 mm or more, clogging easily occurs due to the mixing of small soil particles. Further, when filling the crushed stones, the water supply pipe 18 is exposed to the upper opening of the casing pipe 6 to supply water, thereby suppressing spouting of groundwater,
In addition, the crushing stones can be reduced in humility and the crushed stones can be charged and filled smoothly without resistance. 1 crushed stone to the top of the net bag 17
When 5 is filled, the closing is stopped by the shutter 16,
Next, the hopper 9 is lifted for each net bag 17 filled with the hanging device 8, and the load cell 7 performs weighing,
Check the filling of the crushed stone 15.
【００１８】計量確認の終了後、ホッパー９を元の位置
に戻し、バンドを外して砕石１５が充填された網袋１７
を、図４（ｂ）のように、ケーシングパイプ６内に落下
させる。次に、ケーシングパイプ６に圧縮空気管１９を
接続した上蓋２０を取り付け、圧縮空気により砕石１５
を抑えながら、ケーシングパイプ６を逆回転させること
により、ケーシングパイプ６のみを引き抜くことができ
る。After the confirmation of weighing, the hopper 9 is returned to its original position, the band is removed, and the net bag 17 filled with the crushed stones 15 is removed.
Is dropped into the casing pipe 6 as shown in FIG. Next, the upper lid 20 to which the compressed air pipe 19 is connected is attached to the casing pipe 6, and the crushed stones 15 are compressed with compressed air.
It is possible to pull out only the casing pipe 6 by rotating the casing pipe 6 in the reverse direction while suppressing the above.
【００１９】以上により、図４（ｃ）のように、地盤２
中に使い捨ての底蓋１２と共に網袋１７入りの砕石柱２
１を形設することができる。さらに、このようにして多
数の砕石柱２１を１２０〜１２５ｍｍの間隔で形設した
後、地盤２上に砂マットまたは砕石マット２２を敷装
し、前記砕石柱２１の頭部と一体にし、必要に応じて土
壌２３による盛土仕上げを行うと共に、砂マットまたは
砕石マット２２の一部をエア抜きのように地表面上に露
呈させることにより、広い範囲に亘って過剰高圧地下水
の排出が可能となる。From the above, as shown in FIG. 4 (c), the ground 2
A crushed stone pillar 2 with a net bag 17 with a disposable bottom lid 12 inside
1 can be formed. Further, after forming a large number of crushed stone columns 21 at intervals of 120 to 125 mm in this way, a sand mat or crushed stone mat 22 is laid on the ground 2 and integrated with the head of the crushed stone columns 21 as necessary. According to the above, the embankment is finished with the soil 23, and a part of the sand mat or the crushed stone mat 22 is exposed on the ground surface like air bleeding, so that excess high-pressure groundwater can be discharged over a wide range. .
【００２０】以上の実施例では、説明の便宜上、単一の
ケーシングパイプにより施工された場合について説明し
たが、本発明の工法は小内径のケーシングパイプを用い
ることに特徴があり、従って、常態として、回転駆動装
置に３〜５本の複数本のケーシングパイプを取り付け、
同時施工することにより、さらに施工性が高められる利
点があり、また、例えば、約１．６ｍの間隔で形設され
る４００ｍｍの径の砕石柱に対し、約１．２ｍの間隔で
形設される１２０ｍｍの径の砕石柱の場合は、同一施工
面積当たりで使用砕石量は数分の１で済み、形設後の地
下水の集水量も十分に多いという利点をも有するもので
ある。In the above embodiments, for the sake of convenience of explanation, the case of constructing with a single casing pipe was explained, but the construction method of the present invention is characterized by using a casing pipe with a small inner diameter, and therefore, as a normal condition. , 3-5 casing pipes are attached to the rotary drive,
Simultaneous construction has the advantage that the workability is further enhanced. For example, for a crushed stone column with a diameter of 400 mm that is formed at an interval of about 1.6 m, it is formed at an interval of about 1.2 m. In the case of a crushed stone column with a diameter of 120 mm, the amount of crushed stone used in the same construction area is only a fraction, and it has the advantage that the amount of groundwater collected after forming is sufficiently large.
【００２１】また、網袋による砕石柱を形設する本発明
の工法は、タンク等既設の構造物における液状化対策と
して、該構造物の直下域に周辺地盤より斜め方向に砕石
柱を形設することができ、土圧等による切断がなく、そ
の機能を維持できる砕石柱を得ることができるものであ
る。Further, in the method of the present invention for forming crushed stone pillars with a net bag, as a countermeasure against liquefaction in an existing structure such as a tank, a crushed stone pillar is formed in a region directly below the structure diagonally from the surrounding ground. It is possible to obtain a crushed stone column that can maintain its function without being cut by earth pressure or the like.
【００２２】[0022]
【発明の効果】以上の説明から明らかなように、本発明
によれば、（１）施工に当たって振動や騒音等の公害問
題を発生しない、（２）小回りの利く比較的小さい機械
で施工でき、従って市街地や既設タンク域等での施工も
容易である、（３）複数の砕石柱の同時施工ができ、施
工性がよい、（４）大径の砕石柱の場合に比べて、本数
が増えても使用砕石の量が少なくて済む、（５）排出残
土は殆ど発生せず、残土処理費用を要しない、（６）砕
石柱は地盤内での狭窄化や切断がなく、且つ集水性が良
い、等公害問題がなく、経済性があって、施工性がよ
く、大地震時の排水促進効果にすぐれた砂地盤の液状化
防止工法が得られる。As is apparent from the above description, according to the present invention, (1) no pollution problems such as vibration and noise are generated in the construction, and (2) the construction can be carried out by a relatively small machine with a small turning ability, Therefore, it is easy to construct in urban areas and existing tank areas. (3) Multiple crushed stone columns can be simultaneously constructed and the workability is good. (4) The number of crushed stone columns is large compared to the case of large diameter crushed stone columns. However, the amount of crushed stone used is small, (5) Almost no discharged soil is generated, and the cost of waste soil treatment is not required. (6) Crushed stone columns have no narrowing or cutting in the ground, and water collection It is possible to obtain a liquefaction prevention method for sand ground that is good, has no pollution problems, is economical, has good workability, and has an excellent drainage promotion effect in the event of a large earthquake.
【００２３】さらに、（７）ケーシングパイプの圧入時
の給水により、地下水の噴き上げやケーシングパイプの
先端ずれを防止できる、（８）砕石充填時の給水によ
り、砕石の詰まりを防止し、充填を円滑に行える、
（９）粒度が略５〜１３ｍｍの砕石の使用により、充填
性および集水性のよい砕石柱が得られる、等施工性がさ
らに改善されるという効果を得ることができる。Furthermore, (7) it is possible to prevent spouting of groundwater and displacement of the tip of the casing pipe by supplying water when the casing pipe is press-fitted. (8) Water supply when crushing crushed stones prevents clogging of crushed stones and ensures smooth filling. Can be done
(9) By using crushed stone having a particle size of approximately 5 to 13 mm, it is possible to obtain the effect that the crushed stone column having good filling property and water collecting property can be obtained, and the workability can be further improved.
【図１】本発明工法の実施状況を示す施工装置の要部側
面図である。FIG. 1 is a side view of a main part of a construction device showing a state of implementation of a method of the present invention.
【図２】図１に示した本発明工法の施工装置の側面図で
ある。FIG. 2 is a side view of the construction apparatus of the method of the present invention shown in FIG.
【図３】本発明工法の実施工程を示す略側面図で、
（ａ）はケーシングパイプのセット工程、（ｂ）はケー
シングパイプの貫入工程、（ｃ）は網袋の挿入工程を、
それぞれ示す図である。FIG. 3 is a schematic side view showing an implementation step of the method of the present invention,
(A) is a casing pipe setting process, (b) is a casing pipe penetration process, (c) is a net bag insertion process,
It is a figure which respectively shows.
【図４】本発明工法の実施工程を示す略側面図で、
（ａ）は砕石の充填工程、（ｂ）はケーシングパイプの
引き抜き工程、（ｃ）はケーシングパイプの引き抜き完
了時を、それぞれ示す図である。FIG. 4 is a schematic side view showing an implementation step of the method of the present invention,
(A) is a diagram showing a crushed stone filling process, (b) is a drawing process of a casing pipe, and (c) is a drawing showing completion of drawing of the casing pipe.
Ａ …… 施工装置 １ …… 装置本体 ２ …… 地盤 ３ …… リーダ ４ …… 回転駆動装置 ５ …… 下部ガイド ６ …… ケーシングパイプ ７ …… ロードセル ８ …… 吊り具 ９ …… ホッパー １１…… スクリュー １２…… 底蓋 １３…… ホッパー受け台 １４…… トラクタショベル １５…… 砕石 １６…… シャッタ １７…… 網袋 １８…… 給水管 １９…… 圧縮空気管 ２０…… 上蓋 ２１…… 砕石柱 ２２…… 砕石マット A …… Construction device 1 …… Device main unit 2 …… Ground 3 …… Leader 4 …… Rotary drive device 5 …… Lower guide 6 …… Casing pipe 7 …… Load cell 8 …… Suspension device 9 …… Hopper 11 …… Screw 12 …… Bottom lid 13 …… Hopper cradle 14 …… Tractor excavator 15 …… Crushed stone 16 …… Shutter 17 …… Mesh bag 18 …… Water supply pipe 19 …… Compressed air pipe 20 …… Top lid 21 …… Crushed stone pillar 22 …… Crushed stone mat
Claims (4)
１５０ｍｍ以下のケーシングパイプを地盤に回転圧入し
た後、該ケーシングパイプ内に合成樹脂製の網袋を挿入
し、該網袋内に砕石を充填して地盤上に至る砕石柱を形
設し、次いで、前記ケーシングパイプを抜き出し、前記
砕石柱の頭部を前記地盤上に敷装する砂マット又は砕石
マットと一体化させることを特徴とする砂地盤の液状化
防止工法。1. A casing pipe having an inner diameter of 150 mm or less having a screw formed on the outer periphery of the tip is rotationally press-fitted into the ground, and then a synthetic resin net bag is inserted into the casing pipe, and the net bag is filled with crushed stone. Then, a crushed stone column extending to the ground is formed, then the casing pipe is extracted, and the head of the crushed stone column is integrated with a sand mat or a crushed stone mat to be laid on the ground. Ground liquefaction prevention method.
ケーシングパイプ内に給水しながら行うことを特徴とす
る請求項１記載の砂地盤の液状化防止工法。2. The method for preventing liquefaction of sand ground according to claim 1, wherein the casing pipe is rotationally press-fitted while water is supplied into the casing pipe.
プ内に給水しながら行うことを特徴とする請求項１又は
２に記載の砂地盤の液状化防止工法。3. The method for preventing liquefaction of sand ground according to claim 1, wherein the crushed stone is filled while water is supplied into the casing pipe.
したものであることを特徴とする請求項１乃至３に記載
の砂地盤の液状化防止工法。4. The method for preventing liquefaction of sand ground according to any one of claims 1 to 3, wherein the crushed stone mainly has a particle size of 5 to 13 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5308948A JP2743055B2 (en) | 1993-12-09 | 1993-12-09 | Liquefaction prevention method for sand ground |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5308948A JP2743055B2 (en) | 1993-12-09 | 1993-12-09 | Liquefaction prevention method for sand ground |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07158044A true JPH07158044A (en) | 1995-06-20 |
| JP2743055B2 JP2743055B2 (en) | 1998-04-22 |
Family
ID=17987184
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5308948A Expired - Lifetime JP2743055B2 (en) | 1993-12-09 | 1993-12-09 | Liquefaction prevention method for sand ground |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2743055B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5011456B1 (en) * | 2012-02-07 | 2012-08-29 | グラウンドシステム株式会社 | Ground liquefaction prevention and strengthening method |
| JP2013023978A (en) * | 2011-07-25 | 2013-02-04 | Nippon Steel & Sumikin Metal Products Co Ltd | Method for reinforcing foundation for small-scale building |
| JP2013185338A (en) * | 2012-03-07 | 2013-09-19 | Kentec Inc | Ground reinforcement pile |
| JP2016176275A (en) * | 2015-03-20 | 2016-10-06 | Ｊｆｅスチール株式会社 | Sand compaction pile material, sand compaction pile and sand compaction pile developing method |
| JP2017101512A (en) * | 2015-12-04 | 2017-06-08 | 新日鉄住金エンジニアリング株式会社 | Construction method crushed stone pile, construction jig of crushed stone pile and construction system of crushed stone pile |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6149018A (en) * | 1984-08-16 | 1986-03-10 | Fudo Constr Co Ltd | Construction of sand pile by casing shorten than improved length |
| JPH01226919A (en) * | 1988-03-04 | 1989-09-11 | Nakatomi Kurimoto | Improvement of weak ground |
| JPH0238617A (en) * | 1988-07-29 | 1990-02-08 | Hazama Gumi Ltd | Gravel drain pile and execution thereof |
| JPH03125796A (en) * | 1989-10-11 | 1991-05-29 | Nkk Corp | Underground excavator |
-
1993
- 1993-12-09 JP JP5308948A patent/JP2743055B2/en not_active Expired - Lifetime
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6149018A (en) * | 1984-08-16 | 1986-03-10 | Fudo Constr Co Ltd | Construction of sand pile by casing shorten than improved length |
| JPH01226919A (en) * | 1988-03-04 | 1989-09-11 | Nakatomi Kurimoto | Improvement of weak ground |
| JPH0238617A (en) * | 1988-07-29 | 1990-02-08 | Hazama Gumi Ltd | Gravel drain pile and execution thereof |
| JPH03125796A (en) * | 1989-10-11 | 1991-05-29 | Nkk Corp | Underground excavator |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013023978A (en) * | 2011-07-25 | 2013-02-04 | Nippon Steel & Sumikin Metal Products Co Ltd | Method for reinforcing foundation for small-scale building |
| JP5011456B1 (en) * | 2012-02-07 | 2012-08-29 | グラウンドシステム株式会社 | Ground liquefaction prevention and strengthening method |
| JP2013185338A (en) * | 2012-03-07 | 2013-09-19 | Kentec Inc | Ground reinforcement pile |
| JP2016176275A (en) * | 2015-03-20 | 2016-10-06 | Ｊｆｅスチール株式会社 | Sand compaction pile material, sand compaction pile and sand compaction pile developing method |
| JP2017101512A (en) * | 2015-12-04 | 2017-06-08 | 新日鉄住金エンジニアリング株式会社 | Construction method crushed stone pile, construction jig of crushed stone pile and construction system of crushed stone pile |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2743055B2 (en) | 1998-04-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2018102180A6 (en) | Anti-clogging strengthened permeable pile and construction method | |
| CN110778328B (en) | Loess tunnel entrance section construction method for passing through landslide body | |
| CN106836244A (en) | Method for protecting steep slope roadbed by combining anti-slide piles and gabion high retaining wall | |
| JP3694735B2 (en) | Underground seepage drainage structure and construction method | |
| CN107587502B (en) | Construction method for rotary drilling hole-forming pressure-grouting cement soil occlusion curtain pile | |
| CN101008178B (en) | Soft base processing construction process using excavating and stirring method | |
| CN101591906A (en) | The method for processing foundation of intubate, multipass vacuum well-point dewatering dynamic consolidation | |
| KR100421540B1 (en) | VCPS : Process for Treating Weak Soil with Vibrated Crushed Stone Compaction Pile Reinforced with Sand | |
| JPH07158044A (en) | Sand ground liquefaction preventing work method | |
| CN102966109A (en) | Method for constructing zonal deep foundation pit bottom sealing of soft soil foundation | |
| CN110821512B (en) | Loess tunnel entrance opening section pre-reinforcing and excavating construction method passing through landslide body | |
| CN110438973A (en) | A kind of reinforcement means of soft foundation | |
| CN103603340B (en) | Flexible protective prevents the spiral-digging pore cast-in-place pile construction method of collapse hole | |
| JP3669288B2 (en) | Liquefaction prevention method | |
| CN108277778A (en) | A kind of filling mud bag supports compound fill structure and filling mud bag fill construction method | |
| JP3530262B2 (en) | Construction method of pile with water hole | |
| JP4092411B2 (en) | Soil disposal method, foundation pile construction method to treat the soil | |
| KR100343419B1 (en) | Gravel Drain Process and Gravel Compaction Pile Process for Treating Soft Ground and Apparatuses for the Processes | |
| JP3886127B2 (en) | How to install rainwater penetration pot | |
| JP3576259B2 (en) | Piles with water holes | |
| JP4346078B2 (en) | Ground improvement method | |
| CN218373948U (en) | Pile structure for slope reinforcement and drainage | |
| JP2001182046A (en) | Consolidation accelerating method | |
| CN210104710U (en) | Weak soil foundation drainage well reinforced structure | |
| JP6915800B2 (en) | Construction method of crushed stone structure and crushed stone structure |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090206 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 11 Free format text: PAYMENT UNTIL: 20090206 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100206 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 12 Free format text: PAYMENT UNTIL: 20100206 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 13 Free format text: PAYMENT UNTIL: 20110206 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 14 Free format text: PAYMENT UNTIL: 20120206 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 15 Free format text: PAYMENT UNTIL: 20130206 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140206 Year of fee payment: 16 |
|
| EXPY | Cancellation because of completion of term |