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JP4596962B2 - Improved structure of soft ground and its improved construction method - Google Patents

Improved structure of soft ground and its improved construction method Download PDF

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JP4596962B2
JP4596962B2 JP2005116772A JP2005116772A JP4596962B2 JP 4596962 B2 JP4596962 B2 JP 4596962B2 JP 2005116772 A JP2005116772 A JP 2005116772A JP 2005116772 A JP2005116772 A JP 2005116772A JP 4596962 B2 JP4596962 B2 JP 4596962B2
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soft ground
material layer
swelling
vertical drain
layer
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JP2006291645A (en
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浩二 小野田
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Penta Ocean Construction Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/40—Protecting water resources
    • Y02A20/402—River restoration

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Description

本願発明は軟弱地盤の改良構造およびその改良工法に関するものである。   The present invention relates to an improved structure of soft ground and an improved construction method thereof.

河川や湖沼などの軟弱地盤、または埋立地などの軟弱地盤の改良工法として、いわゆる真空圧密工法が知られている。この真空圧密工法は、例えば図４に示すように、サンドマット２０の上から軟弱地盤２１に鉛直ドレーン材４を所定間隔をもって列状に打設し、これらの鉛直ドレーン材４の上端部に気密キャップ２２を介して排水ホース２３を連結し、該排水ホース２３が接続された集水管２４に真空ポンプ２５を接続し、これで鉛直ドレーン材２６内を負圧にして圧密および排水による軟弱地盤２１の改良を行うものである。また圧密および排水を促進させるために、サンドマット２０を気密シート２７で覆うことも行われている。またその他の軟弱地盤の改良工法としては、例えば特開２００４−４４１６８号公報の発明がある。
特開２００４−４４１６８号公報 A so-called vacuum consolidation method is known as an improvement method for soft ground such as rivers and lakes, or soft ground such as landfills. In this vacuum consolidation method, for example, as shown in FIG. 4, vertical drain members 4 are placed in rows at predetermined intervals on the soft ground 21 from above the sand mat 20, and the upper ends of these vertical drain members 4 are airtight. A drainage hose 23 is connected via a cap 22, and a vacuum pump 25 is connected to a water collecting pipe 24 to which the drainage hose 23 is connected. This causes the inside of the vertical drain material 26 to be negatively pressured and soft ground 21 due to compaction and drainage. It is intended to improve. In order to promote compaction and drainage, the sand mat 20 is also covered with an airtight sheet 27. As another method for improving soft ground, there is an invention disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-44168.
JP 2004-44168 A

しかし、上記の方法は気密性を確保するために、鉛直ドレーン材２６の上端部を軟弱地盤の表面層２８より深く打設するために、この表面層２８が改良されず、かつ排水ホース２３も長くなるため非経済的であった。また鉛直ドレーン材２６の打設時に軟弱地盤に気密キャップ２２の大きさの打設孔２９が形成されるため、これが空気抜けの通路となって鉛直ドレーン材２６の負圧が低減されるという問題があった。また地盤改良後に気密キャップ２２などが表面層２８の下側に残存してしまうという問題があった。さらに、サンドマット２０を気密シートで覆うと手間がかかるという問題があった。   However, in the above method, in order to ensure airtightness, the upper surface portion of the vertical drain material 26 is driven deeper than the surface layer 28 of the soft ground. It was uneconomical because it was long. In addition, when the vertical drain material 26 is placed, since a placement hole 29 having the size of the airtight cap 22 is formed in the soft ground, this serves as a passage for air escape and the negative pressure of the vertical drain material 26 is reduced. was there. Further, there is a problem that the airtight cap 22 and the like remain below the surface layer 28 after the ground improvement. Furthermore, there is a problem that it takes time and effort to cover the sand mat 20 with an airtight sheet.

本願発明は上記のような問題に鑑みてなされたものであり、その目的は、表面層まで改良でき、かつ気密キャップなどを地中から撤去できる軟弱地盤の改良構造およびその改良工法を提供することである。   The present invention has been made in view of the above problems, and an object of the present invention is to provide an improved soft ground structure and an improved construction method that can improve the surface layer and remove an airtight cap from the ground. It is.

以上の課題を解決するための本願発明の軟弱地盤の改良構造は、気密性の下面シートと、該下面シートの上面に形成した膨潤材層と、該膨潤材層の上面に設けたサンドマットとからなる気密シール層が軟弱地盤の上面に形成され、前記気密シール層の上から軟弱地盤に鉛直ドレーン材が打設され、該鉛直ドレーン材に真空ポンプが接続されてなることを特徴とする。また膨潤材層の上面には多数の孔が開いた上面シートが敷設されたことを含む。また膨潤材層はベントナイト、高分子吸水材、ベントナイトまたは高分子吸水材と土砂との混合材、ベントナイトまたは高分子吸水材と古紙との混合材のいずれかであることを含む。また鉛直ドレーン材の上端部には連結具を介して排水ホースが連結され、前記連結具が膨潤材層の近傍に埋設されたことを含むものである。   An improved structure of the soft ground of the present invention for solving the above-mentioned problems is an airtight bottom sheet, a swelling material layer formed on the top surface of the bottom sheet, and a sand mat provided on the top surface of the swelling material layer. An airtight seal layer is formed on the upper surface of the soft ground, a vertical drain material is placed on the soft ground from above the airtight seal layer, and a vacuum pump is connected to the vertical drain material. In addition, the upper surface of the swelling material layer includes an upper surface sheet having a large number of holes. The swelling material layer includes any one of bentonite, a polymeric water-absorbing material, bentonite or a mixed material of polymeric water-absorbing material and earth and sand, or a mixed material of bentonite or polymeric water-absorbing material and waste paper. In addition, a drain hose is connected to the upper end portion of the vertical drain material via a connector, and the connector is embedded in the vicinity of the swelling material layer.

また軟弱地盤の改良工法は、気密性の下面シートと、該下面シートの上面に形成した膨潤材層と、該膨潤材層の上面に設けたサンドマットとからなる気密シール層を軟弱地盤の上面に形成し、前記気密シール層の上から軟弱地盤に鉛直ドレーン材を打設し、該鉛直ドレーン材に接続した真空ポンプで排水することを特徴とする。また膨潤材層の上面に多数の孔が開いた上面シートを敷設することを含む。また膨潤材層はベントナイト、高分子吸水材、ベントナイトまたは高分子吸水材と土砂との混合材、ベントナイトまたは高分子吸水材と古紙との混合材のいずれかであることを含む。また鉛直ドレーン材は上端部に設置した連結具が膨潤材層の近傍に位置するように打設することを含む。また膨潤材層が適切な含水状態を保持することを含むものである。   Further, the soft ground improvement method includes an airtight sealing layer comprising an airtight lower surface sheet, a swelling material layer formed on the upper surface of the lower surface sheet, and a sand mat provided on the upper surface of the swelling material layer. A vertical drain material is placed on the soft ground from above the hermetic seal layer and drained by a vacuum pump connected to the vertical drain material. Further, the method includes laying a top sheet having a large number of holes on the top surface of the swelling material layer. The swelling material layer includes any one of bentonite, a polymeric water-absorbing material, bentonite or a mixed material of polymeric water-absorbing material and earth and sand, or a mixed material of bentonite or polymeric water-absorbing material and waste paper. In addition, the vertical drain material includes placing the connecting tool installed at the upper end so that it is located in the vicinity of the swelling material layer. Moreover, the swelling material layer includes maintaining an appropriate water-containing state.

膨潤材層が自己修復力を有するので、鉛直ドレーン材の打設孔が膨潤材層によって塞がれて気密性が保持される。また鉛直ドレーン材が表面層の近傍まで打設されるため、この表面層付近まで十分に改良することができる。また鉛直ドレーン材の連結具を全て地中から撤去することができる。また膨潤材層が上下面シートで包まれているため、地盤改良後に膨潤材層をシートで包んだままで撤去することができる。また膨潤材層が適切な含水状態を保持するため、膨潤材層の自己修復力を高めることができる。また上面シートに多数の孔を開けたことにより、この孔から膨潤材層に散水などによる給水をすることができる。   Since the swelling material layer has a self-repairing force, the placement hole of the vertical drain material is blocked by the swelling material layer, and the airtightness is maintained. Further, since the vertical drain material is driven to the vicinity of the surface layer, it can be sufficiently improved to the vicinity of the surface layer. Moreover, it is possible to remove all the connectors of the vertical drain material from the ground. Moreover, since the swelling material layer is wrapped with the upper and lower sheets, the swelling material layer can be removed while being wrapped with the sheet after the ground improvement. Moreover, since the swelling material layer maintains an appropriate water-containing state, the self-healing power of the swelling material layer can be increased. Further, by providing a large number of holes in the top sheet, water can be supplied from the holes to the swelling material layer by watering or the like.

以下、本願発明の軟弱地盤の改良構造およびその改良工法の実施の形態を図面に基づいて説明する。はじめに軟弱地盤の改良構造について説明し、この後に軟弱地盤の改良工法について説明するが、各実施の形態において同じ構成は同じ符号を使用して説明し、異なった構成にのみ異なった符号を付して説明する。   Hereinafter, an improved structure of soft ground and an embodiment of the improved construction method of the present invention will be described with reference to the drawings. First, an improved structure of soft ground will be described, and then an improved construction method of soft ground will be described.In each embodiment, the same components will be described using the same symbols, and only different components will be given different symbols. I will explain.

この軟弱地盤の改良構造１は、図１および図２に示すように、軟弱地盤２の上面に形成された気密シール層３の上から軟弱地盤２に鉛直ドレーン材４が打設されて構成されている。   As shown in FIGS. 1 and 2, the soft ground improved structure 1 is configured by placing a vertical drain material 4 on the soft ground 2 from above an airtight seal layer 3 formed on the upper surface of the soft ground 2. ing.

気密シール層３は、軟弱地盤２の上面に敷設されたビニールシートからなる不透水性の下面シート５と、この下面シート５の上に設置されたベントナイト、高吸水性樹脂や吸水ポリマなどの高分子吸水材、ベントナイトまたは高分子吸水材と土砂との混合材、ベントナイトまたは高分子吸水材と古紙との混合材などからなる膨潤材層６と、この膨潤材層６の上面を覆った上面シート７と、この上面シート７の上に形成されたサンドマット８とから構成されている。また上面シート７は膨潤材層６に必要な水を供給する透水性のシートであり、例えば不織布または多数の小孔９が開口されたものであり、この小孔９からの給水によって膨潤材層６が十分な水分を保持している。   The airtight seal layer 3 includes a water-impermeable lower surface sheet 5 made of a vinyl sheet laid on the upper surface of the soft ground 2, and bentonite, a highly water-absorbing resin, a water-absorbing polymer, and the like installed on the lower surface sheet 5. Swelling material layer 6 made of molecular water-absorbing material, bentonite or polymer water-absorbing material and earth and sand, bentonite or polymer water-absorbing material and waste paper, etc., and top sheet covering the upper surface of this swelling material layer 6 7 and a sand mat 8 formed on the top sheet 7. The top sheet 7 is a water-permeable sheet for supplying water necessary for the swelling material layer 6. For example, the nonwoven fabric or a plurality of small holes 9 are opened. 6 has sufficient moisture.

また鉛直ドレーン材４は適宜間隔をもって列状に打設され、上端部の連結具である気密キャップ１０を介して排水ホース１１が接続され、該排水ホース１１が、真空ポンプ１２を接続した集水管１３に連結されている。   The vertical drain members 4 are placed in rows at appropriate intervals, and a drain hose 11 is connected via an airtight cap 10 which is a coupling tool at the upper end. The drain hose 11 is connected to a water collecting pipe to which a vacuum pump 12 is connected. 13.

この気密キャップ１０は膨潤材層６の近傍に打設されている。また膨潤材層６は自己修復力、すなわち復元力を有するため、鉛直ドレーン材４の打設孔１４などを塞ぐことができる。すなわち、図２の（２）に示すように、上下面シート７、５には鉛直ドレーン材４の打設によって孔１５が開けられるが、この孔１５は膨潤材層６が鉛直ドレーン材４に沿って密着することにより塞がれる。   The hermetic cap 10 is placed in the vicinity of the swelling material layer 6. Further, since the swelling material layer 6 has a self-repairing force, that is, a restoring force, it can close the placement hole 14 of the vertical drain material 4 and the like. That is, as shown in FIG. 2 (2), a hole 15 is formed in the upper and lower sheets 7, 5 by placing the vertical drain material 4. The swelling material layer 6 is formed in the vertical drain material 4 in the hole 15. It closes by sticking along.

したがって、鉛直ドレーン材４が上下面シート７、５を破って軟弱地盤２に打設されたとしても、軟弱地盤２はあたかも破られていない下面シート５で覆われた状態になっているため、気密性を保持することができる。   Therefore, even if the vertical drain material 4 breaks the upper and lower surface sheets 7 and 5 and is placed on the soft ground 2, the soft ground 2 is covered with the lower surface sheet 5 that is not torn, Airtightness can be maintained.

また鉛直ドレーン材４が軟弱地盤の表面層１６まで打設され、かつ気密キャップ１０が地表面１７の近くに位置するため、この気密キャップ１０と、これに接続された排水ホース１１とを簡単に地中から撤去することができるとともに、排水ホース１１の長さも短くすることができるので経費の節減にもなる。   Further, since the vertical drain material 4 is driven to the surface layer 16 of the soft ground and the airtight cap 10 is located near the ground surface 17, the airtight cap 10 and the drainage hose 11 connected thereto can be easily obtained. It can be removed from the ground, and the length of the drainage hose 11 can be shortened, thereby reducing costs.

したがって、真空ポンプ１２の駆動によって鉛直ドレーン材４を負圧にすると、ここから軟弱地盤２中の水が吸収され、これが集水管１３に吸い上げられて排水されることにより、軟弱地盤２の排水および圧密が促進されて地盤の表面層１６までの改良がおこなわれる。また鉛直ドレーン材４の打設孔１４が膨潤材層６で塞がれて気密性が保持されているため、鉛直ドレーン材４の負圧が低減されず、効率的な排水および圧密を行うことができる。   Therefore, when the vertical drain material 4 is brought to a negative pressure by driving the vacuum pump 12, the water in the soft ground 2 is absorbed from here, and the water is sucked up and drained to the water collecting pipe 13, thereby draining the soft ground 2 and Consolidation is promoted and the surface layer 16 of the ground is improved. Moreover, since the placement hole 14 of the vertical drain material 4 is closed by the swelling material layer 6 and the airtightness is maintained, the negative pressure of the vertical drain material 4 is not reduced, and efficient drainage and consolidation are performed. Can do.

次に、軟弱地盤の改良工法を図３に基づいて説明する。まず、（１）に示すように、軟弱地盤２の上面にビニールシートからなる下面シート５を敷設して、軟弱地盤２を被覆する。これは軟弱地盤２の気密性を保持するとともに、後述する膨潤材層６が軟弱地盤２に混じらないようにするためである。   Next, an improved construction method for soft ground will be described with reference to FIG. First, as shown in (1), a lower surface sheet 5 made of a vinyl sheet is laid on the upper surface of the soft ground 2 to cover the soft ground 2. This is for keeping the airtightness of the soft ground 2 and preventing the swelling material layer 6 described later from being mixed into the soft ground 2.

次に、この下面シート５の上に、適宜厚さのベントナイト、高吸水性樹脂や吸水ポリマなどの高分子吸水材、ベントナイトまたは高分子吸水材と土砂との混合材、ベントナイトまたは高分子吸水材と古紙との混合材などからなる膨潤材層６を形成する。この膨潤材層６には自己修復力、すなわち復元力を発揮できるように適度な水が含有されている。   Next, on this lower surface sheet 5, bentonite having an appropriate thickness, a polymer water-absorbing material such as a highly water-absorbing resin or a water-absorbing polymer, bentonite or a mixture of a polymer water-absorbing material and earth, bentonite or a polymer water-absorbing material A swelling material layer 6 made of a mixed material of paper and waste paper is formed. The swelling material layer 6 contains appropriate water so as to exhibit a self-repairing force, that is, a restoring force.

次に、（２）に示すように、この膨潤材層６の上に多数の小孔９が開口された上面シート７を敷設して膨潤材層６を被覆する。この膨潤材層６には上面シート７の小孔９から十分な水が供給されるようになっている。このように膨潤材層６は上下面シート７、５で包み込まれて軟弱地盤２およびサンドマット８に混じらないようになっている。   Next, as shown in (2), a top sheet 7 having a large number of small holes 9 is laid on the swelling material layer 6 to cover the swelling material layer 6. Sufficient water is supplied to the swelling material layer 6 from the small holes 9 of the top sheet 7. Thus, the swelling material layer 6 is wrapped with the upper and lower sheets 7 and 5 so as not to be mixed with the soft ground 2 and the sand mat 8.

次に、（３）に示すように、上下面シート７、５で包み込まれた膨潤材層６の上に適宜厚さのサンドマット８を敷き詰めると、上下面シート７、５で包み込まれた膨潤材層６とサンドマット８とからなる気密シール層３が形成され、下面シート５はサンドマット８の下面である軟弱地盤２の上面に敷設されている。   Next, as shown in (3), when a sand mat 8 having an appropriate thickness is spread on the swelling material layer 6 wrapped with the upper and lower sheets 7, 5, the swelling wrapped with the upper and lower sheets 7, 5 An airtight seal layer 3 including a material layer 6 and a sand mat 8 is formed, and the lower surface sheet 5 is laid on the upper surface of the soft ground 2 which is the lower surface of the sand mat 8.

次に、この気密シール層３の上から軟弱地盤２に鉛直ドレーン材４を適宜間隔をもって列状に打設し、上端部の連結具である気密キャップ１０が膨潤材層６の近傍に位置するようにする。この鉛直ドレーン材４の打設により、上下面シート７、５は破られて孔１５が開けられるが、この孔１５と打設孔１４とが、図２の（２）に示すように、膨潤材層６の自己修復力、すなわち復元力によって塞がれて気密性が保持される。そして気密キャップ１０を介して接続した排水ホース１１を集水管１３に接続し、該集水管１３に真空ポンプ１２を接続する。   Next, the vertical drain material 4 is driven in rows from the top of the hermetic seal layer 3 onto the soft ground 2 at an appropriate interval, and the hermetic cap 10 as a connecting tool at the upper end is positioned in the vicinity of the swelling material layer 6. Like that. By placing the vertical drain material 4, the upper and lower sheets 7, 5 are torn and a hole 15 is formed. The hole 15 and the placement hole 14 swell as shown in FIG. 2 (2). The material layer 6 is closed by the self-repairing force, that is, the restoring force, and the airtightness is maintained. Then, the drain hose 11 connected through the airtight cap 10 is connected to the water collecting pipe 13, and the vacuum pump 12 is connected to the water collecting pipe 13.

次に、この真空ポンプ１２の駆動によって鉛直ドレーン材４を負圧にすると、ここから軟弱地盤２中の水が吸収され、これが集水管１３に吸い上げられて排水されることにより、軟弱地盤２の排水および圧密が促進されて表面層１６までの改良がおこなわれる。そして、必要に応じてサンドマット８上からの散水を行って鉛直ドレーン材４の負圧による膨潤材層６の乾燥状態を解消して、この膨潤材層６の復元力を常に保持するようにする。   Next, when the vacuum drain 12 is driven to a negative pressure by driving the vacuum pump 12, the water in the soft ground 2 is absorbed from here, and the water is sucked into the water collecting pipe 13 and drained. Drainage and compaction are promoted to improve the surface layer 16. Then, if necessary, water is sprayed from the sand mat 8 to eliminate the dry state of the swelling material layer 6 due to the negative pressure of the vertical drain material 4 so that the restoring force of the swelling material layer 6 is always maintained. To do.

次に、このような排水および圧密の促進により軟弱地盤２の改良が終了した後に、サンドマット８を撤去するとともに、膨潤材層６を上下面シート７、５で包み込んで撤去するとともに、地表面の近くにある気密キャップ１０を撤去する。   Next, after the improvement of the soft ground 2 is completed by the promotion of such drainage and consolidation, the sand mat 8 is removed, and the swelling material layer 6 is wrapped with the upper and lower sheets 7 and 5 and removed. The hermetic cap 10 near is removed.

このように膨潤材層６は上下面シート７、５で包み込んで撤去することができるとともに、気密キャップ１０も地表面の近くにあるため簡単かつ迅速に撤去することができる。   In this way, the swelling material layer 6 can be wrapped and removed by the upper and lower sheets 7 and 5 and the airtight cap 10 is also close to the ground surface, so that it can be removed easily and quickly.

軟弱地盤の改良構造を示すものであり、（１）は平面図、（２）は（１）のＡ−Ａ線断面図である。The improved structure of a soft ground is shown, (1) is a top view, (2) is the sectional view on the AA line of (1). （１）は軟弱地盤の改良構造の断面図、（２）は（１）の拡大断面図、（３）は（２）のＢ−Ｂ線断面図である。(1) is a sectional view of an improved structure of soft ground, (2) is an enlarged sectional view of (1), and (3) is a sectional view taken along line BB of (2). 軟弱地盤の改良工法を示すものであり、（１）は軟弱地盤の上面に上下面シートで包み込んだ膨潤材層を設置した断面図、（２）は膨潤材層の断面図、（３）は膨潤材層の上にサンドマットを敷設して気密シール層を形成した断面図、（４）は気密シール層の上から鉛直ドレーン材を打設する断面図である。The improvement method of soft ground is shown, (1) is a cross-sectional view in which a swelling material layer wrapped with upper and lower sheets is installed on the upper surface of the soft ground, (2) is a cross-sectional view of the swelling material layer, (3) is A cross-sectional view in which a sand mat is laid on the swelling material layer to form an airtight seal layer, and (4) is a cross-sectional view in which a vertical drain material is placed from above the airtight seal layer. 従来の軟弱地盤の改良構造を示すものであり、（１）は断面図、（２）は拡大断面図、（３）はＣ−Ｃ線断面図である。The conventional soft ground improvement structure is shown, (1) is sectional drawing, (2) is an expanded sectional view, (3) is CC sectional view taken on the line.

符号の説明Explanation of symbols

１ 軟弱地盤の改良構造
２、２１ 軟弱地盤
３ 気密シール層
４、２６ 鉛直ドレーン材
５ 下面シート
６ 膨潤材層
７ 上面シート
８、２０ サンドマット
９ 小孔
１０、２２ 気密キャップ
１１、２３ 排水ホース
１２、２５ 真空ポンプ
１３、２４ 集水管
１４、２９ 打設孔
１５ 孔
１６、２８ 表面層
１７ 地表面
２７ 気密シート DESCRIPTION OF SYMBOLS 1 Improved structure of soft ground 2, 21 Soft ground 3 Airtight seal layer 4, 26 Vertical drain material 5 Lower surface sheet 6 Swelling material layer 7 Upper surface sheet 8, 20 Sand mat 9 Small hole 10, 22 Airtight cap 11, 23 Drain hose 12 , 25 Vacuum pump 13, 24 Water collecting pipe 14, 29 Casting hole 15 Hole 16, 28 Surface layer 17 Ground surface 27 Airtight sheet

Claims (9)

気密性の下面シートと、該下面シートの上面に形成した膨潤材層と、該膨潤材層の上面に設けたサンドマットとからなる気密シール層が軟弱地盤の上面に形成され、該気密シール層の上から軟弱地盤に鉛直ドレーン材が打設され、該鉛直ドレーン材に真空ポンプが接続されてなることを特徴とする軟弱地盤の改良構造。   An airtight seal layer comprising an airtight lower surface sheet, a swelling material layer formed on the upper surface of the lower surface sheet, and a sand mat provided on the upper surface of the swelling material layer is formed on the upper surface of the soft ground, and the airtight seal layer An improved structure for soft ground, characterized in that a vertical drain material is placed on the soft ground from above, and a vacuum pump is connected to the vertical drain material. 膨潤材層の上面には透水性の上面シートが敷設されたことを特徴とする請求項１に記載の軟弱地盤の改良構造。   The improved structure for soft ground according to claim 1, wherein a water-permeable upper surface sheet is laid on the upper surface of the swelling material layer. 膨潤材層はベントナイト、高分子吸水材、ベントナイトまたは高分子吸水材と土砂との混合材、ベントナイトまたは高分子吸水材と古紙との混合材のいずれかであることを特徴とする請求項１または２に記載の軟弱地盤の改良構造。   The swelling material layer is any one of bentonite, polymer water-absorbing material, bentonite or a mixture of polymer water-absorbing material and earth and sand, bentonite or a mixture of polymer water-absorbing material and waste paper. 2. An improved structure of soft ground as described in 2. 鉛直ドレーン材の上端部には連結具を介して排水ホースが連結され、前記連結具が膨潤材層の近傍に埋設されたことを特徴とする請求項１〜３のいずれかに記載の軟弱地盤の改良構造。   The soft ground according to any one of claims 1 to 3, wherein a drainage hose is connected to an upper end portion of the vertical drain material via a connection tool, and the connection tool is embedded in the vicinity of the swelling material layer. Improved structure. 気密性の下面シートと、該下面シートの上面に形成した膨潤材層と、該膨潤材層の上面に設けたサンドマットとからなる気密シール層を軟弱地盤の上面に形成し、該気密シール層の上から軟弱地盤に鉛直ドレーン材を打設し、該鉛直ドレーン材に接続した真空ポンプで排水することを特徴とする軟弱地盤の改良工法。   An airtight sealing layer comprising an airtight lower surface sheet, a swelling material layer formed on the upper surface of the lower surface sheet, and a sand mat provided on the upper surface of the swelling material layer is formed on the upper surface of the soft ground, and the airtight sealing layer A method for improving soft ground, characterized in that a vertical drain material is placed on the soft ground from above and drained by a vacuum pump connected to the vertical drain material. 膨潤材層の上面に多数の孔が開いた上面シートを敷設することを特徴とする請求項５に記載の軟弱地盤の改良工法。   6. The improvement method for soft ground according to claim 5, wherein an upper surface sheet having a large number of holes is laid on the upper surface of the swelling material layer. 膨潤材層はベントナイト、高分子吸水材、ベントナイトまたは高分子吸水材と土砂との混合材、ベントナイトまたは高分子吸水材と古紙との混合材のいずれかであることを特徴とする請求項５または６に記載の軟弱地盤の改良工法。   6. The swelling material layer is any one of bentonite, polymer water-absorbing material, bentonite or a mixture of polymer water-absorbing material and earth and sand, bentonite or a mixture of polymer water-absorbing material and waste paper. 6. An improved construction method for soft ground according to 6. 鉛直ドレーン材は上端部に設置した連結具が膨潤材層の近傍に位置するように打設することを特徴とする請求項５〜７に記載の軟弱地盤の改良工法。   The method for improving soft ground according to claim 5, wherein the vertical drain material is placed so that a coupling device installed at the upper end portion is positioned in the vicinity of the swelling material layer. 膨潤材層が適切な含水状態を保持することを特徴とする請求項５〜８のいずれかに記載の軟弱地盤の改良工法。   The swelling method of the soft ground according to any one of claims 5 to 8, wherein the swelling material layer maintains an appropriate water-containing state.
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CN101851914B (en) * 2010-06-09 2011-06-29 天津大学 Method of Regulating Ventilation and Transforming Vacuum to Rapidly Consolidate Dredging Fill
CN102493428A (en) * 2011-12-09 2012-06-13 中国建筑西南勘察设计研究院有限公司 Vacuum preloading structure for reinforcing soft foundation
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CN103243704B (en) * 2013-05-02 2015-03-18 浙江大学舟山海洋研究中心 Shallow mud foundation treatment method
JP6448133B2 (en) * 2015-03-13 2019-01-09 五洋建設株式会社 Vacuum consolidation method and vacuum consolidation system
CN104775415B (en) * 2015-04-03 2016-06-15 重庆大学 Blow and fill out workplatform and the constructional method that super soft ground is reinforced fast
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JP2004044168A (en) * 2002-07-10 2004-02-12 Shimizu Corp Vacuum consolidation method

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