JP3704643B2 - Improvement method and equipment for soft ground - Google Patents

Improvement method and equipment for soft ground Download PDF

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JP3704643B2
JP3704643B2 JP2000285802A JP2000285802A JP3704643B2 JP 3704643 B2 JP3704643 B2 JP 3704643B2 JP 2000285802 A JP2000285802 A JP 2000285802A JP 2000285802 A JP2000285802 A JP 2000285802A JP 3704643 B2 JP3704643 B2 JP 3704643B2
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drainage
improved ground
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和義 中熊
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Maruyama Kogyo KK
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Maruyama Kogyo KK
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Description

【０００１】
【発明の属する技術分野】
本発明は、例えば湖沼周囲の埋立造成区域などの軟弱地盤に多量に含まれる水を排出することで、軟弱地盤を硬質地盤へと改良する軟弱地盤の改良工法及び改良装置に関する。詳細には真空圧の伝播経路とは別経路で改良地盤からの水を排出することで、改良地盤内の真空圧を改良地盤内の隅々まで伝達させて、より効率よく地盤を改良することができる軟弱地盤の改良工法及び改良装置に関する。
【０００２】
【従来の技術】
従来、軟弱地盤の改良工法としては、改良地盤中に所定の間隔をおいて設置した鉛直ドレーン材を通じて改良地盤中に真空圧を負荷することで、前記改良地盤中に改良地盤周辺部と隔離された減圧領域を造り出すようにしたものがある。
【０００３】
図２に示す改良工法は、改良地盤Ａ中に所定の間隔をおいて設置した鉛直ドレーン材１と、この各鉛直ドレーン材１に接続した水平ドレーン材（図示しない）と、水平ドレーン材（図示しない）に接続した集水管２と、この集水管２に真空タンク３を介して接続する真空ポンプ４とを有する改良装置を用いた工法である。
【０００４】
図２に示す装置を用いた改良工法は以下のとおりである。すなわち、真空ポンプ４を稼働させ、この真空ポンプ４からの真空圧で真空タンク３内が所定の減圧度に達すると、減圧逆止弁（図示しない）が開き、これに接続する集水管２が減圧される。次いで、この集水管２に接続する水平ドレーン材（図示しない）に真空圧が伝播し水平ドレーン材（図示しない）が減圧される。さらにこの水平ドレーン材（図示しない）に接続する鉛直ドレーン材１に真空圧が伝播し、鉛直ドレーン材１内を所定の真空圧（０．４気圧以下）とする。
【０００５】
さらに鉛直ドレーン材１内の真空圧は、鉛直ドレーン材１周囲の地盤Ａへと伝播し、鉛直ドレーン材１を中心にその周囲の地盤Ａを減圧状態の領域（以下減圧領域という）とする。
【０００６】
真空圧は、減圧領域となった鉛直ドレーン材１周りの地盤Ａから、さらにその周囲の地盤Ａへと伝播してゆき、鉛直ドレーン材１周りの地盤Ａへと向かう地盤加圧（水圧、土圧）が発生する。
【０００７】
この地盤加圧に従って、鉛直ドレーン材１周囲の地盤Ａに含まれる間隙水が鉛直ドレーン材１に向かって吸い出され、鉛直ドレーン材１、水平ドレーン材（図示しない）及び集水管２を排水経路として排水され、これに伴って鉛直ドレーン材１周囲の地盤Ａの外側も減圧領域となる。
【０００８】
こうして、鉛直ドレーン材１を中心にしてその周囲の地盤Ａに減圧領域が広がり、やがて改良地盤Ａ全域が減圧領域となり、同時に鉛直ドレーン材１を中心にして圧密、強度増加が進行し、改良地盤Ａ全域の圧密、強度増加が行われることになる。
【０００９】
【発明が解決しようとする課題】
ところが、上記改良工法にあっては、真空ポンプ４からの真空圧の伝播経路である、真空ポンプ４、真空タンク３、水平ドレーン材（図示しない）、集水管２及び鉛直ドレーン材１が、そのまま改良地盤から吸い出された間隙水の排水経路となっている。
【００１０】
このため、この改良工法にあっては、真空圧を負荷した当初、集水管２内には、鉛直ドレーン材１及び水平ドレーン材（図示しない）を通じて改良地盤Ａからの間隙水が一気に大量に流れ込んで該集水管２内を満たし、真空ポンプ４からの真空圧が鉛直ドレーン材１へ伝わらないか、あるいは伝わりにくくなってしまい、改良効率を著しく阻害していた。
【００１１】
本発明は、このような事情に鑑みなされたものであり、真空圧の伝播経路とは別経路で改良地盤からの水を排出することで、改良地盤内の真空圧を改良地盤内の隅々まで伝達させて、より効率よく地盤を改良することができる軟弱地盤の改良工法及び改良装置を提供することを目的とするものである。
【００１２】
【課題を解決するための手段】
上記目的を達成するため、請求項１〜５記載の発明は、改良地盤内に鉛直排水路を造成し、前記鉛直排水路を通じて改良地盤内に真空圧を負荷し、前記改良地盤内の間隙水を吸い上げることで、軟弱地盤を硬質地盤へと改良する軟弱地盤の改良工法において、
前記間隙水と空気とを分離する排水タンクを含む独立した排水経路を前記改良地盤内に設けて、前記排水タンク内の間隙水を強制的に改良地盤外へ排水するようにしたことを特徴とする軟弱地盤の改良工法をその要旨とした。
【００１３】
請求項６〜１０記載の発明は、改良地盤内に造成した鉛直排水路を通じて前記改良地盤内に真空圧を負荷し、前記改良地盤内の間隙水を吸い上げることで、軟弱地盤を硬質地盤へと改良する軟弱地盤の改良装置において、
前記間隙水と空気とを分離する排水タンクを含み、前記排水タンク内の間隙水を強制的に改良地盤外へ排水する独立した排水経路を前記改良地盤内に設けたことを特徴とする軟弱地盤の改良装置をその要旨とした。
【００１４】
【発明の実施の形態】
以下、本発明の軟弱地盤の改良工法及び改良装置を図面に示した一形態に従って詳細に説明する。まず本発明の軟弱地盤の改良装置（以下、改良装置という）について説明する。図１に示すように、本発明の改良装置は、改良地盤Ａ内に造成した鉛直排水路を通じて改良地盤Ａ内に真空圧を負荷し、前記改良地盤Ａ内の間隙水を吸い上げることで、改良地盤Ａ内に改良地盤周辺部Ｂと隔離された減圧領域を造り出すものである。
【００１５】
図１に示す改良装置は、改良地盤Ａ内に所定の間隔をおいて設置した鉛直ドレーン材１１と、この各鉛直ドレーン材１１に接続した水平ドレーン材（図示しない）と、水平ドレーン材（図示しない）に接続した集水管１２と、この集水管１２に真空タンク１３を介して接続する真空ポンプ１４とを有している。
【００１６】
鉛直ドレーン材１１は鉛直排水路を構成するものであり、地盤加圧の環境でも真空圧（減圧）の伝播、排水経路としての機能を確保でき、目詰まりせず、沈下による圧縮や減圧で潰れることがないものであれば、その構造、素材、大きさなどは任意である。図１に示す鉛直ドレーン材１１は、長手方向に一定間隔に立てて並べた長尺な平板状の合成樹脂線材に同じく長尺な平板状の合成樹脂線材を直交方向に所定間隔に立てて並べて、これらの合成樹脂線材を交点で接合した合成樹脂ネットと、これを内包する不織布とからなるものを用いた。この鉛直ドレーン材１１にあっては、折れたり曲がったりしても、合成樹脂ネットと不織布とによって形成されている通水経路が確保されており、しかも合成樹脂ネット全体が不織布で覆われていて、目詰まりを生じ難いというメリットがある。
【００１７】
この鉛直ドレーン材１１には水平ドレーン材（図示しない）が接続されている。水平ドレーン材（図示しない）としては、水及び空気が該水平ドレーン（図示しない）の長手方向（水平方向）へと移動できる通路としての機能を持つものならば、線状や帯状、面状のものなど何でもよいが、改良地盤Ａ側からの水及び空気が該水平ドレーン材（図示しない）内部へ侵入する口、例えば孔、スリットなどが、地盤中の砂や土砂などによって閉塞してしまい、水及び空気の水平ドレーン材（図示しない）内部への侵入が困難となったり、同じく改良地盤Ａ中の砂や土砂などによって通路が閉塞して水及び空気が移動できなかったりすることが少ない構造のものが好ましい。図１に示す形態では、前記鉛直ドレーン材１１と同じ構造（合成樹脂ネットとその表面を覆う不織布とからなるもの）を持つものを用いた。この場合、水及び空気は、合成樹脂ネットを覆う不織布側から侵入し、合成樹脂ネットと不織布との隙間、及び不織布の構成繊維相互間を通して移動するようになる。
【００１８】
この水平ドレーン材（図示しない）の所要箇所に集水管１２が接続されている。集水管１２は、管周面に多数の孔を設けた有孔管であり、この集水管１２の一端側には真空タンク１３を介して真空ポンプ１４が接続されている。そして、前記真空ポンプ１４からの真空圧が真空タンク１３を介して集水管１２へと伝達され、さらにはこの集水管１２に繋がる水平ドレーン材（図示しない）及び鉛直ドレーン材１１を介して改良地盤Ａへの真空圧が伝播するようになっている。
【００１９】
また図１に示す改良装置は、集水管１２下側の改良地盤Ａ内に配置した排水タンク１６と、この排水タンク１６に接続した改良地盤Ａ外へと通じる排水管１９とを有している。集水管１２の下側にはセパレータ１５を介して排水タンク１６が接続されている。集水管１２に集水された改良地盤Ａから吸い出された間隙水は、セパレータ１５により空気と分離されて、集水管１２下側の排水タンク１６に重力に従って流れ込み、ここに貯留されるようになっている。図１に示す排水タンク１６内には排水ポンプ１７が内蔵されていて、排水タンク１６内に貯留された水が該排水タンク１６に連結パイプ１８を介して接続された排水管１９を通じて装置外（改良地盤Ａ外）へと強制的に排水されるようになっている。
【００２０】
尚、排水タンク１６の形状や大きさはまったく任意であり、改良地盤の規模や地盤の種類などを考慮して適宜決定すればよい。また排水タンク１６に内蔵されている排水ポンプ１７の種類も任意であり、改良地盤の規模や地盤の種類、価格などを考慮して適宜決定すればよい。
【００２１】
排水管１９は、改良地盤Ａから吸い出された間隙水を装置外（改良地盤Ａ外）へと導く管であり、その設置位置は何処でも良いが、前記集水管１２よりも下側であることが好ましい。また排水管１９の径も太ければそれだけ排水効率は高くなる一方、設置作業が困難となるので、改良地盤の規模や地盤の種類などを考慮して適宜決定するとよい。
【００２２】
次に、本発明の軟弱地盤の改良工法（以下、改良工法という）について説明する。図１に示すように、本発明の改良工法は、改良地盤Ａ内に鉛直排水路を造成し、前記鉛直排水路を通じて改良地盤内Ａに真空圧を負荷し、改良地盤Ａ内の間隙水を吸い上げることで、軟弱地盤を硬質地盤へと改良するものである。
【００２３】
図１に示す装置を用いた改良工法は以下のとおりである。まず、鉛直ドレーン材１１を改良地盤Ａ中に所定間隔に打設する。鉛直ドレーン材１１を打設する間隔は、負荷された真空圧による真空圧伝播の可能な範囲が望ましく、具体的には１ｍ程度である。この鉛直ドレーン材１１をマンドレル（図示しない）に内挿した状態で地盤Ａ中に貫入し、鉛直ドレーン材１１を改良地盤Ａ内に残したままマンドレル（図示しない）を引き上げることで打設することができる。
【００２４】
こうして鉛直ドレーン材１１を改良地盤Ａ中に所定の間隔をおいて打設することで、改良地盤Ａ内には所定の間隔をおいて鉛直状の排水柱が造成されることになり、各排水柱間の改良地盤Ａ中に含まれる水及び空気がこの鉛直ドレーン材１１を排水経路として吸い上げられるようになっている。
【００２５】
この鉛直ドレーン材１１には水平ドレーン材（図示しない）が接続されている。鉛直ドレーン材１１は、その上端部分が改良地盤Ａの上面に突出するように打ち込まれており、この突出部分１１ａに水平ドレーン材（図示しない）を接触するように平行状に配置する。
【００２６】
この水平ドレーン材（図示しない）の所要箇所に集水管１２を接続する。集水管１２は、管周面に多数の孔を設けた有孔管であり、この集水管１２の一端側には真空タンク１３を介して真空ポンプ１４が接続されている。そして、真空ポンプ１４からの真空圧が真空タンク１３を介して集水管１２へと伝達され、さらにはこの集水管１２に繋がる水平ドレーン材（図示しない）及び鉛直ドレーン材１１を介して改良地盤Ａへの真空圧が伝播するようになっている。
【００２７】
このように、図１に示す改良装置を用いた改良工法にあっては、真空ポンプ１４からの真空圧が、真空タンク１３、水平ドレーン材（図示しない）、集水管１２及び鉛直ドレーン材１１へと伝播し、鉛直ドレーン材１１内を所定の真空圧（０．４気圧以下）とするようになっている。
【００２８】
さらに鉛直ドレーン材１１内の真空圧は、鉛直ドレーン材１１周囲の地盤Ａへと伝播し、鉛直ドレーン材１１を中心にその周囲の地盤Ａを減圧状態の領域（以下減圧領域という）とする。
【００２９】
真空圧は、減圧領域となった鉛直ドレーン材１１周りの地盤Ａから、さらにその周囲の地盤Ａへと伝播してゆき、鉛直ドレーン材１１周りの地盤Ａへと向かう地盤加圧（水圧、土圧）が発生する。
【００３０】
この地盤加圧に従って、鉛直ドレーン材１１周囲の地盤Ａに含まれる間隙水が鉛直ドレーン材１１に向かって吸い出され、鉛直ドレーン材１１、水平ドレーン材（図示しない）及び集水管１２を排水経路として排水され、これに伴って鉛直ドレーン材１１周囲の地盤Ａの外側も減圧領域となる。
【００３１】
こうして、鉛直ドレーン材１１を中心にしてその周囲の地盤Ａに減圧領域が広がり、やがて改良地盤Ａ全域が減圧領域となり、同時に鉛直ドレーン材１１を中心にして圧密、強度増加が進行し、改良地盤Ａ全域の圧密、強度増加が行われることになる。
【００３２】
一方、改良地盤Ａから吸い出された間隙水は、以下の排水経路を通って排水されるようになっている。すなわち、鉛直ドレーン材１１及び水平ドレーン材（図示しない）を通じて吸い出された改良地盤Ａからの間隙水は、一旦集水管２内に入り込む。
【００３３】
図１に示すように、集水管１２の下側の改良地盤Ａ内にはセパレータ１５を介して排水タンク１６が配置されている。集水管１２に集水された間隙水は、セパレータ１５により空気と分離されて、集水管１２下側の排水タンク１６に重力に従って流れ込み、ここに貯留される。
【００３４】
この排水タンク１６内には排水ポンプ１７が内蔵されており、排水タンク１６内に貯留された水を該排水タンク１６に連結パイプ１８を介して接続された排水管１９を通じて装置外（改良地盤Ａ外）へと強制的に排水するようになっている。
【００３５】
尚、排水タンク１６の設置位置は、集水管１２内の水が重力に従って流れ込むように集水管１２下側の改良地盤Ａ内であれば何処でもよい。
【００３６】
尚、図面に示す形態では、排水タンク１６内には排水ポンプ１７を内蔵させて、排水タンク１６内に貯留された水を強制的に装置外（改良地盤Ａ外）へ排水するようにしたが、改良地盤の規模や地盤の種類によっては、排水ポンプ１７を内蔵していない排水タンク１６を用いることもできる。
【００３７】
尚、図面に示す形態では、真空ポンプ１４からの真空圧を鉛直ドレーン材１１内部が０．４気圧以下となるように負荷するようにしたが、これに限らず、改良地盤の軟弱の程度、例えば地盤の含水率などを考慮して適宜決定すればよい。
【００３８】
尚、上記実施の形態に示した例は、単なる説明例に過ぎず、例えば地盤中に負荷する真空圧を、改良当初は高くし、その後は低い状態に維持したり、高い状態と低い状態とを交互に繰り返したりするなど、特許請求の範囲の欄に記載された範囲内で自由に変更することができる。
【００３９】
【発明の効果】
本発明の本工法にあっては、間隙水と空気とを分離する排水タンクを含む独立した排水経路を改良地盤内に設けて、前記排水タンク内の間隙水を強制的に改良地盤外へ排水するようにしたので、より効率よく地盤を改良することができる。
【００４０】
本発明の本装置にあっては、間隙水と空気とを分離する排水タンクを含み、前記排水タンク内の間隙水を強制的に改良地盤外へ排水する独立した排水経路を前記改良地盤内に設けたので、より効率よく地盤を改良することができる。
【図面の簡単な説明】
【図１】本発明の改良装置を示した模式図。
【図２】従来の改良装置を示した模式図。
【符号の説明】
１１・・・鉛直ドレーン材
１２・・・集水管
１３・・・真空タンク
１４・・・真空ポンプ
１５・・・セパレータ
１６・・・排水タンク
１７・・・排水ポンプ
１８・・・排水管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improved construction method and an improved apparatus for soft ground that improves soft ground to hard ground by discharging a large amount of water in the soft ground such as a landfill construction area around a lake. Specifically, by discharging water from the improved ground through a route different from the propagation path of the vacuum pressure, the vacuum pressure in the improved ground is transmitted to every corner of the improved ground, and the ground is improved more efficiently. The present invention relates to an improved construction method and an improved apparatus for soft ground.
[0002]
[Prior art]
Conventionally, as an improvement method of soft ground, a vacuum pressure is applied to the improved ground through a vertical drain material installed at a predetermined interval in the improved ground, so that the improved ground is isolated from the periphery of the improved ground. There is something that created a reduced pressure area.
[0003]
The improved construction method shown in FIG. 2 includes a vertical drain material 1 installed at a predetermined interval in the improved ground A, a horizontal drain material (not shown) connected to each vertical drain material 1, and a horizontal drain material (shown). This is a construction method using an improved apparatus having a water collecting pipe 2 connected to the water collecting pipe 2 and a vacuum pump 4 connected to the water collecting pipe 2 via a vacuum tank 3.
[0004]
The improved construction method using the apparatus shown in FIG. 2 is as follows. That is, when the vacuum pump 4 is operated and the inside of the vacuum tank 3 reaches a predetermined pressure reduction degree by the vacuum pressure from the vacuum pump 4, a pressure reducing check valve (not shown) is opened, and the water collecting pipe 2 connected thereto is opened. Depressurized. Next, the vacuum pressure propagates to the horizontal drain material (not shown) connected to the water collecting pipe 2 and the horizontal drain material (not shown) is depressurized. Further, the vacuum pressure is transmitted to the vertical drain material 1 connected to the horizontal drain material (not shown), and the inside of the vertical drain material 1 is set to a predetermined vacuum pressure (0.4 atm or less).
[0005]
Further, the vacuum pressure in the vertical drain material 1 propagates to the ground A around the vertical drain material 1, and the ground A around the vertical drain material 1 is defined as a decompressed region (hereinafter referred to as a decompressed region).
[0006]
The vacuum pressure propagates from the ground A around the vertical drain material 1 in the reduced pressure region to the surrounding ground A, and is applied to the ground pressure (water pressure, soil) toward the ground A around the vertical drain material 1. Pressure).
[0007]
In accordance with this ground pressurization, pore water contained in the ground A around the vertical drain material 1 is sucked out toward the vertical drain material 1, and the vertical drain material 1, the horizontal drain material (not shown), and the water collecting pipe 2 are drained along the drainage path. As a result, the outside of the ground A around the vertical drain material 1 also becomes a decompression region.
[0008]
Thus, the decompression region spreads around the vertical drain material 1 to the surrounding ground A, and the entire improved ground A eventually becomes the decompression region. At the same time, the consolidation and strength increase proceed with the vertical drain material 1 as the center, and the improved ground The consolidation and strength increase of the entire area A will be performed.
[0009]
[Problems to be solved by the invention]
However, in the improved construction method, the vacuum pump 4, the vacuum tank 3, the horizontal drain material (not shown), the water collection pipe 2 and the vertical drain material 1, which are the propagation paths of the vacuum pressure from the vacuum pump 4, remain as they are. It is a drainage route for pore water sucked out from the improved ground.
[0010]
For this reason, in this improved construction method, when the vacuum pressure is applied, a large amount of pore water from the improved ground A flows into the water collecting pipe 2 at once through the vertical drain material 1 and the horizontal drain material (not shown). Thus, the water collecting pipe 2 is filled, and the vacuum pressure from the vacuum pump 4 is not transmitted to the vertical drain material 1 or is difficult to be transmitted, and the improvement efficiency is significantly hindered.
[0011]
The present invention has been made in view of such circumstances, and by discharging water from the improved ground through a path different from the propagation path of the vacuum pressure, the vacuum pressure in the improved ground is reduced in every corner of the improved ground. An object of the present invention is to provide an improved construction method and an improved apparatus for soft ground that can be transmitted to the ground and improve the ground more efficiently.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claims 1 to 5 is characterized in that a vertical drainage channel is created in the improved ground, a vacuum pressure is applied to the improved ground through the vertical drainage channel, and pore water in the improved ground is formed. In the improvement method of soft ground that improves soft ground to hard ground by sucking up
An independent drainage path including a drainage tank for separating the interstitial water and air is provided in the improved ground, and the interstitial water in the drainage tank is forcibly drained outside the improved ground. The gist of the improved construction method of soft ground.
[0013]
The invention according to claims 6 to 10 applies a vacuum pressure to the improved ground through a vertical drainage channel formed in the improved ground, and sucks up the pore water in the improved ground, thereby converting the soft ground into the hard ground. In the improvement device of soft ground to improve,
A soft ground comprising a drainage tank for separating the interstitial water and air, and an independent drainage path for forcibly draining the interstitial water in the drainage tank to the outside of the improved ground is provided in the improved ground. The gist of the improved apparatus was as follows.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the improvement method and the improvement apparatus of the soft ground of this invention are demonstrated in detail according to the form shown in drawing. First, a soft ground improving device (hereinafter referred to as an improving device) according to the present invention will be described. As shown in FIG. 1, the improved device of the present invention is improved by applying a vacuum pressure to the improved ground A through the vertical drainage channel created in the improved ground A and sucking up the pore water in the improved ground A. A decompression area isolated from the improved ground peripheral part B is created in the ground A.
[0015]
The improved apparatus shown in FIG. 1 includes a vertical drain material 11 installed at a predetermined interval in the improved ground A, a horizontal drain material (not shown) connected to each vertical drain material 11, and a horizontal drain material (shown). A water collecting pipe 12 connected to the water collecting pipe 12 and a vacuum pump 14 connected to the water collecting pipe 12 via a vacuum tank 13.
[0016]
The vertical drain material 11 constitutes a vertical drainage channel, and can transmit the vacuum pressure (decompression) and function as a drainage channel even in an environment of ground pressurization, and does not clog, and is crushed by compression or decompression due to subsidence. If there is nothing, the structure, material, size, etc. are arbitrary. The vertical drain material 11 shown in FIG. 1 is formed by arranging the same flat plate-like synthetic resin wires arranged at regular intervals in the orthogonal direction on the long plate-like synthetic resin wires arranged at regular intervals in the longitudinal direction. A synthetic resin net obtained by joining these synthetic resin wires at intersections and a non-woven fabric containing the synthetic resin net were used. In this vertical drain material 11, even if it bends or bends, the water passage formed by the synthetic resin net and the nonwoven fabric is secured, and the entire synthetic resin net is covered with the nonwoven fabric. There is a merit that clogging is difficult to occur.
[0017]
A horizontal drain material (not shown) is connected to the vertical drain material 11. As a horizontal drain material (not shown), if it has a function as a passage through which water and air can move in the longitudinal direction (horizontal direction) of the horizontal drain (not shown), it is linear, strip-like, or planar. Anything can be used, but the water and air from the improved ground A side enter the inside of the horizontal drain material (not shown), for example, holes, slits, etc., are blocked by sand or earth in the ground, A structure in which it is difficult for water and air to enter the horizontal drain material (not shown), or the passage is blocked by sand or earth in the improved ground A so that water and air cannot move. Are preferred. In the form shown in FIG. 1, a material having the same structure as the vertical drain material 11 (consisting of a synthetic resin net and a nonwoven fabric covering the surface thereof) is used. In this case, water and air enter from the side of the nonwoven fabric covering the synthetic resin net and move through the gap between the synthetic resin net and the nonwoven fabric and between the constituent fibers of the nonwoven fabric.
[0018]
A water collecting pipe 12 is connected to a required portion of the horizontal drain material (not shown). The water collecting pipe 12 is a perforated pipe provided with a large number of holes on the pipe peripheral surface, and a vacuum pump 14 is connected to one end side of the water collecting pipe 12 via a vacuum tank 13. The vacuum pressure from the vacuum pump 14 is transmitted to the water collecting pipe 12 via the vacuum tank 13, and further, the improved ground is connected via the horizontal drain material (not shown) and the vertical drain material 11 connected to the water collecting pipe 12. The vacuum pressure to A propagates.
[0019]
Further, the improved apparatus shown in FIG. 1 has a drain tank 16 disposed in the improved ground A below the water collecting pipe 12 and a drain pipe 19 connected to the drain tank 16 and connected to the outside of the improved ground A. . A drain tank 16 is connected to the lower side of the water collecting pipe 12 via a separator 15. The pore water sucked out from the improved ground A collected in the water collecting pipe 12 is separated from the air by the separator 15, flows into the drain tank 16 below the water collecting pipe 12 according to gravity, and is stored therein. It has become. A drainage pump 17 is built in the drainage tank 16 shown in FIG. 1, and water stored in the drainage tank 16 is outside the apparatus through a drainage pipe 19 connected to the drainage tank 16 via a connecting pipe 18 ( It is forced to drain to the improved ground A).
[0020]
The shape and size of the drainage tank 16 are completely arbitrary, and may be appropriately determined in consideration of the scale of the improved ground and the type of ground. The type of the drain pump 17 built in the drain tank 16 is also arbitrary, and may be appropriately determined in consideration of the scale of the improved ground, the type of ground, the price, and the like.
[0021]
The drainage pipe 19 is a pipe that guides the pore water sucked out from the improved ground A to the outside of the apparatus (outside the improved ground A), and the installation position thereof may be anywhere, but is lower than the water collecting pipe 12. It is preferable. Further, if the diameter of the drain pipe 19 is thicker, the drainage efficiency becomes higher accordingly, but the installation work becomes difficult. Therefore, the drain pipe 19 may be appropriately determined in consideration of the scale of the improved ground and the kind of the ground.
[0022]
Next, an improved construction method (hereinafter referred to as an improved construction method) for soft ground according to the present invention will be described. As shown in FIG. 1, according to the improved construction method of the present invention, a vertical drainage channel is created in the improved ground A, a vacuum pressure is applied to the improved ground A through the vertical drainage channel, and pore water in the improved ground A is discharged. By sucking up, soft ground is improved to hard ground.
[0023]
The improved construction method using the apparatus shown in FIG. 1 is as follows. First, the vertical drain material 11 is placed in the improved ground A at a predetermined interval. The interval for placing the vertical drain material 11 is preferably within a range in which the vacuum pressure can be propagated by the applied vacuum pressure, and is specifically about 1 m. The vertical drain material 11 is inserted into the ground A while being inserted into a mandrel (not shown), and is placed by pulling up the mandrel (not shown) while leaving the vertical drain material 11 in the improved ground A. Can do.
[0024]
Thus, by placing the vertical drain material 11 in the improved ground A with a predetermined interval, vertical drainage columns are created in the improved ground A with a predetermined interval. Water and air contained in the improved ground A between the columns can be sucked up using the vertical drain material 11 as a drainage path.
[0025]
A horizontal drain material (not shown) is connected to the vertical drain material 11. The vertical drain material 11 is driven so that the upper end portion protrudes from the upper surface of the improved ground A, and a horizontal drain material (not shown) is arranged in parallel so as to contact the protruding portion 11a.
[0026]
A water collecting pipe 12 is connected to a required portion of the horizontal drain material (not shown). The water collecting pipe 12 is a perforated pipe provided with a large number of holes on the pipe peripheral surface, and a vacuum pump 14 is connected to one end side of the water collecting pipe 12 via a vacuum tank 13. Then, the vacuum pressure from the vacuum pump 14 is transmitted to the water collecting pipe 12 via the vacuum tank 13, and further, the improved ground A is connected via the horizontal drain material (not shown) and the vertical drain material 11 connected to the water collecting pipe 12. The vacuum pressure to propagates.
[0027]
Thus, in the improved construction method using the improved apparatus shown in FIG. 1, the vacuum pressure from the vacuum pump 14 is applied to the vacuum tank 13, the horizontal drain material (not shown), the water collection pipe 12 and the vertical drain material 11. The inside of the vertical drain material 11 is set to a predetermined vacuum pressure (0.4 atm or less).
[0028]
Further, the vacuum pressure in the vertical drain material 11 propagates to the ground A around the vertical drain material 11, and the ground A around the vertical drain material 11 is defined as a decompressed region (hereinafter referred to as a decompressed region).
[0029]
The vacuum pressure propagates from the ground A around the vertical drain material 11 in the reduced pressure region to the surrounding ground A, and then pressurizes the ground (water pressure, soil) toward the ground A around the vertical drain material 11. Pressure).
[0030]
In accordance with this ground pressurization, pore water contained in the ground A around the vertical drain material 11 is sucked out toward the vertical drain material 11, and the vertical drain material 11, the horizontal drain material (not shown), and the water collection pipe 12 are drained. As a result, the outside of the ground A around the vertical drain material 11 also becomes a decompression region.
[0031]
Thus, the decompression region spreads around the vertical drain material 11 to the surrounding ground A, and the entire improved ground A eventually becomes the decompression region. At the same time, the consolidation and strength increase proceed with the vertical drain material 11 as the center. The consolidation and strength increase of the entire area A will be performed.
[0032]
On the other hand, the pore water sucked out from the improved ground A is drained through the following drainage path. That is, the pore water from the improved ground A sucked through the vertical drain material 11 and the horizontal drain material (not shown) once enters the water collecting pipe 2.
[0033]
As shown in FIG. 1, a drain tank 16 is disposed in the improved ground A below the water collecting pipe 12 via a separator 15. The pore water collected in the water collection pipe 12 is separated from the air by the separator 15, flows into the drain tank 16 below the water collection pipe 12 according to gravity, and is stored therein.
[0034]
A drain pump 17 is built in the drain tank 16, and water stored in the drain tank 16 is connected to the drain tank 16 through a drain pipe 19 connected to the drain tank 16 via a connecting pipe 18 (improved ground A). The water is forcibly drained to the outside).
[0035]
The installation position of the drainage tank 16 may be anywhere as long as it is in the improved ground A below the water collection pipe 12 so that the water in the water collection pipe 12 flows according to gravity.
[0036]
In the embodiment shown in the drawings, a drainage pump 17 is built in the drainage tank 16 to forcibly drain the water stored in the drainage tank 16 to the outside of the device (outside the improved ground A). Depending on the scale of the improved ground and the type of ground, a drainage tank 16 that does not include the drainage pump 17 can be used.
[0037]
In the form shown in the drawings, the vacuum pressure from the vacuum pump 14 is applied so that the inside of the vertical drain material 11 is 0.4 atm or less, but not limited to this, the degree of softness of the improved ground, For example, it may be determined appropriately in consideration of the moisture content of the ground.
[0038]
In addition, the example shown in the above embodiment is merely an illustrative example.For example, the vacuum pressure applied to the ground is increased at the beginning of the improvement, and thereafter maintained at a low state, or a high state and a low state. Can be freely changed within the range described in the appended claims, such as alternately repeating.
[0039]
【The invention's effect】
In the present construction method of the present invention, an independent drainage path including a drainage tank for separating pore water and air is provided in the improved ground, and the pore water in the drainage tank is forcibly drained outside the improved ground. Since it was done, the ground can be improved more efficiently.
[0040]
The apparatus of the present invention includes a drainage tank that separates pore water and air, and an independent drainage path for forcibly draining the gap water in the drainage tank to the outside of the improved ground in the improved ground. Since it was provided, the ground can be improved more efficiently.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an improved apparatus of the present invention.
FIG. 2 is a schematic diagram showing a conventional improved apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Vertical drain material 12 ... Water collection pipe 13 ... Vacuum tank 14 ... Vacuum pump 15 ... Separator 16 ... Drain tank 17 ... Drain pump 18 ... Drain pipe

Claims (10)

改良する軟弱地盤（以下改良地盤という）内に鉛直排水路を造成し、前記鉛直排水路を通じて改良地盤内に真空圧を負荷し、前記改良地盤内の間隙水を吸い上げることで、軟弱地盤を硬質地盤へと改良する軟弱地盤の改良工法において、
前記間隙水と空気とを分離する排水タンクを含む独立した排水経路を前記改良地盤内に設けて、前記排水タンク内の間隙水を強制的に改良地盤外へ排水するようにしたことを特徴とする軟弱地盤の改良工法。By creating a vertical drainage channel in the soft ground to be improved (hereinafter referred to as the improved ground), applying a vacuum pressure to the improved ground through the vertical drainage channel, and sucking up pore water in the improved ground, the soft ground is hardened In the improvement method of soft ground to improve to the ground,
An independent drainage path including a drainage tank for separating the interstitial water and air is provided in the improved ground, and the interstitial water in the drainage tank is forcibly drained outside the improved ground. To improve soft ground. 改良地盤内に所定の間隔をおいて設置した各鉛直ドレーン材により鉛直排水路を構成し、前記鉛直ドレーン材の上端部分に水平ドレーン材を介して繋がる集水管下側の改良地盤内に改良地盤外へと通じる排水タンクを配置して、前記集水管に集水された間隙水を前記排水タンクへと排水し、次いで、排水タンク内の間隙水を改良地盤外へ強制的に排水することを特徴とする請求項１記載の軟弱地盤の改良工法。A vertical drainage channel is constituted by each vertical drain material installed at a predetermined interval in the improved ground, and the improved ground is located in the improved ground below the collecting pipe connected to the upper end portion of the vertical drain material via the horizontal drain material. Disposing a drainage tank that leads to the outside, draining the interstitial water collected in the water collection pipe to the drainage tank, and then forcibly draining the interstitial water in the drainage tank outside the improved ground The method for improving soft ground according to claim 1, characterized in that: 集水管と排水タンクとがセパレータを介して接続されていて、このセパレータによって前記集水管内の間隙水を前記排水タンクへと導水するようにしたことを特徴とする請求項２記載の軟弱地盤の改良工法。3. The soft ground according to claim 2, wherein the water collecting pipe and the drainage tank are connected via a separator, and the gap water in the water collecting pipe is guided to the drainage tank by the separator. Improved construction method. 排水タンク内に排水ポンプを内蔵させて、前記排水タンク内の間隙水を改良地盤外へと強制的に排水することを特徴とする請求項２又は３記載の軟弱地盤の改良工法。4. The method for improving soft ground according to claim 2, wherein a drainage pump is built in the drainage tank, and the pore water in the drainage tank is forcibly drained out of the improved ground. 排水タンク内の間隙水を排水管を通じて改良地盤外へと強制的に排水することを特徴とする請求項２〜４のいずれかに記載の軟弱地盤の改良工法。The improvement method for soft ground according to any one of claims 2 to 4, wherein pore water in the drainage tank is forcibly drained out of the improved ground through a drain pipe. 改良地盤内に造成した鉛直排水路を通じて前記改良地盤内に真空圧を負荷し、前記改良地盤内の間隙水を吸い上げることで、軟弱地盤を硬質地盤へと改良する軟弱地盤の改良装置において、
前記間隙水と空気とを分離する排水タンクを含み、前記排水タンク内の間隙水を強制的に改良地盤外へ排水する独立した排水経路を前記改良地盤内に設けたことを特徴とする軟弱地盤の改良装置。In the improvement device of the soft ground that improves the soft ground to the hard ground by applying a vacuum pressure in the improved ground through the vertical drainage channel created in the improved ground and sucking up the pore water in the improved ground,
A soft ground comprising a drainage tank for separating the interstitial water and air, and an independent drainage path for forcibly draining the interstitial water in the drainage tank to the outside of the improved ground is provided in the improved ground. Improved equipment. 鉛直排水路が改良地盤内に所定の間隔をおいて打設される鉛直ドレーン材により構成されており、この鉛直ドレーン材の上端部分に水平ドレーン材を介して繋がる集水管下側の改良地盤内に前記改良地盤外へと通じる排水タンクを配置したことを特徴とする請求項６記載の軟弱地盤の改良装置。The vertical drainage channel is made of vertical drain material that is placed in the improved ground at a predetermined interval, and the inside of the improved ground below the water collection pipe that is connected to the upper end of this vertical drain material via the horizontal drain material 7. A device for improving soft ground according to claim 6, wherein a drainage tank communicating with the outside of the improved ground is disposed. 集水管と排水タンクとがセパレータを介して接続されていることを特徴とする請求項７記載の軟弱地盤の改良装置。The apparatus for improving soft ground according to claim 7, wherein the water collecting pipe and the drainage tank are connected via a separator. 排水タンクが排水ポンプを内蔵することを特徴とする請求項７又は８記載の軟弱地盤の改良装置。The apparatus for improving soft ground according to claim 7 or 8, wherein the drainage tank includes a drainage pump. 排水タンクに排水管が接続されており、この排水管を通じて排水タンク内の間隙水を改良地盤外へと強制的に排水することを特徴とする請求項７〜９のいずれかに記載の軟弱地盤の改良装置。The soft ground according to any one of claims 7 to 9, wherein a drain pipe is connected to the drain tank, and pore water in the drain tank is forcibly drained out of the improved ground through the drain pipe. Improved equipment.
JP2000285802A 2000-09-20 2000-09-20 Improvement method and equipment for soft ground Expired - Lifetime JP3704643B2 (en)

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