JP2001193048A - Ground and/or water quality improvement method by injection of gaseous dissolution water - Google Patents
Ground and/or water quality improvement method by injection of gaseous dissolution waterInfo
- Publication number
- JP2001193048A JP2001193048A JP2000004780A JP2000004780A JP2001193048A JP 2001193048 A JP2001193048 A JP 2001193048A JP 2000004780 A JP2000004780 A JP 2000004780A JP 2000004780 A JP2000004780 A JP 2000004780A JP 2001193048 A JP2001193048 A JP 2001193048A
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- Prior art keywords
- water
- pressure
- air
- ground
- dissolved
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Classifications
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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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、地盤の間隙流体に
着目した液状化防止地盤改良工法、地盤の間隙水の圧力
減少と透水抵抗の増加に着目した地盤改良工法、これら
の品質管理手法、さらに湖沼などの水質に関して含有酸
素量を増加させる等の水質環境の改善に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefaction-preventing ground improvement method that focuses on pore fluid in the ground, a ground improvement method that focuses on a decrease in pressure of pore water in the ground and an increase in water permeability resistance, and a quality control method thereof. Further, the present invention relates to improvement of water quality environment such as increasing oxygen content in water quality of lakes and marshes.
【0002】[0002]
【従来の技術】地下水面下で地震時に発生する砂地盤等
の液状化防止のための主な地盤改良工法には、地盤の締
まり、密度を大きくする工法、地下水低下工法、地震時
に発生する過剰間隙水圧を排水するドレーン工法、この
他に固化工法、置換工法などがある。2. Description of the Related Art The main soil improvement methods for preventing liquefaction of sandy ground and the like that occur during an earthquake below groundwater level include a method for tightening and increasing the density of a ground, a method for lowering groundwater, and an excess method for generating an earthquake. There is a drain method that drains pore water pressure, a solidification method, a displacement method, etc.
【0003】上記の他に、液状化対象地盤の地下水(間
隙水)内に空気を混入、或は空気で一部置換する工法が
ある。例えば、特開平8-3975「地盤の液状化防止工
法」、特開平10-102473「砂質地盤の液状化防止工
法」、特開平10-338939「地盤の地震時液状化防止工法
及び、この工法を用いる送排気管構造」等がある。特開
平8-3975「地盤の液状化防止工法」は、揚水により地
下水位を低下させ地盤の間隙に一旦空気を入れ、その後
に上部から注水することにより空隙内に気泡を混在させ
て地下水を不飽和状態にして液状化を防止する工法であ
る。In addition to the above, there is a construction method in which air is mixed into groundwater (pore water) of the ground to be liquefied or partially replaced with air. For example, JP-A-8-3975 "Method for preventing liquefaction of ground", JP-A-10-102473 "Method for preventing liquefaction of sandy ground", JP-A-10-338939 "Method for preventing liquefaction of ground during earthquake, and this method And an exhaust pipe structure using the same. Japanese Unexamined Patent Publication No. Hei 8-3975 "Soil liquefaction prevention method" discloses a method of lowering the groundwater level by pumping water, temporarily injecting air into the gaps in the ground, and then injecting water from above to mix air bubbles in the gaps to prevent groundwater. This is a method to prevent liquefaction by making it saturated.
【0004】2番目の特開平10-102473「砂質地盤の液
状化防止工法」は、地盤中に高圧で空気を噴出して局所
的な流動化状態を引き起こして地盤改良をする方法であ
る、3番目の特開平10-338939「地盤の地震時液状化防
止工法及び、この工法を用いる送排気管構造」は、地盤
中に圧縮空気を吹き込み微細な気泡を混入させることで
液状化を防止しようとするものである。The second Japanese Unexamined Patent Publication No. 10-102473, "Method for preventing liquefaction of sandy ground", is a method of injecting air at high pressure into the ground to cause a local fluidized state to improve the ground. The third Japanese Unexamined Patent Publication No. Hei 10-338939, "Method of preventing liquefaction of ground during earthquakes and structure of air supply / exhaust pipe using this method," aims to prevent liquefaction by blowing compressed air into the ground and mixing fine bubbles. It is assumed that.
【0005】[0005]
【発明が解決しようとする課題】従来から最も良く用い
られてきた液状化防止工法は、地盤を締め固める工法
で、何らかの地盤変状(沈下や水平移動など)を伴うこ
と、既設構造物の直下の改良を共用しながら支障なく改
良工事を行うことは、原理的に困難である。The liquefaction-prevention method that has been most often used in the past is a method of compacting the ground, which involves some deformation of the ground (such as settlement or horizontal movement), and that it is directly under the existing structure. It is in principle difficult to carry out improvement work without hindrance while sharing the improvement.
【0006】地震時に発生する過剰間隙水圧を速やかに
排出させて液状化を防止しようとするドレーン工法は、
工事中の地盤の変状は抑止できるが、ドレーンの設置間
隔を理論的に広げることができないことと排水溝設置の
必要性から共用しながら既設構造物直下の地盤を改良す
ることは原理的に困難である。[0006] A drain construction method for quickly discharging excess pore water pressure generated during an earthquake to prevent liquefaction,
Deformation of the ground during construction can be suppressed, but it is theoretically impossible to improve the ground immediately below the existing structure while sharing the drain installation interval because it cannot be theoretically widened and the need for drainage ditches to be installed. Have difficulty.
【0007】一方、地下水(間隙水)に空気を混入させる
ことで、地震時の間隙水圧の上昇を抑止する液状化防止
工法は、地下水を揚水して空気を入れてから上部から注
水する工法は、排水による地盤変動(沈下)、止水工事
の必要性などの課題がある。改良対象地盤に空気を吹き
込む方法は直裁的であるが、間隙水を押出しながら気泡
を混入させようとするもので、間隙水より軽い空気の注
入では不透気性遮断壁の設置工事等の付帯工事が必要と
されていること、均質な気泡の混入は容易ではない等の
課題がある。On the other hand, a liquefaction-prevention method for suppressing the rise in pore water pressure during an earthquake by mixing air into groundwater (pore water) is a method of pumping groundwater, introducing air, and then pouring water from above. There are problems such as ground deformation due to drainage (subsidence) and necessity of water stoppage work. The method of blowing air into the ground to be improved is straightforward, but it tries to mix air bubbles while extruding pore water, and the injection of air lighter than the pore water involves the installation of impermeable barriers, etc. There are problems such as the necessity of construction and the difficulty of mixing homogeneous air bubbles.
【0008】地下工事などで地下水面以下の地盤を掘削
する場合、排水工事が必要であり、抗土圧構造物(土留
壁など)に作用する圧力のうち、水圧の大きさは重要な
設計要因となる。従来から水圧は地下水位面から静水圧
分布で外力として作用するものとする場合がほとんどで
ある。地盤の透水性を低下させることができれば排水施
設の規模の縮小や、排水工事による近隣に対する影響の
減少が可能であり、更に水圧を軽減できれば抗土圧構造
物の設計を容易にすることが可能になる。When excavating the ground below the groundwater level in underground construction or the like, drainage work is required, and the magnitude of water pressure is an important design factor among pressures acting on anti-earth pressure structures (such as retaining walls). Becomes Conventionally, in most cases, the water pressure acts as an external force in a hydrostatic pressure distribution from the groundwater level. If the permeability of the ground can be reduced, the scale of drainage facilities can be reduced, and the effect of drainage works on nearby areas can be reduced.If the water pressure can be further reduced, the design of anti-earth pressure structures can be facilitated become.
【0009】海上などでの埋立工事で、山砂等を船で輸
送し、所定の場所で船底を開けて土砂を放出することで
土地を造成する場合、土地造成後の間隙水の空気混入量
に関しては全く問題にされてこなかった。土地造成中に
間隙水に十分な気泡を混入させておけば液状化防止に役
立つことになる。湖沼などの水質を改良するため、空気
を噴射する工法は既に実用化されているが、気泡となっ
て水面上に直ちに消出するため効率的ではなく、空気、
酸素を水中に効率的に溶存させることが課題である。In the case of land reclamation work at sea or the like, where mountain sand and the like are transported by ship and the bottom is opened at a predetermined place to release land and sand, land is created. Has never been a problem. If enough air bubbles are mixed into the pore water during land development, it will help prevent liquefaction. In order to improve the water quality of lakes and marshes, the method of injecting air has already been put into practical use, but it is not efficient because it disappears immediately on the water surface as bubbles,
The problem is to efficiently dissolve oxygen in water.
【0010】[0010]
【課題を解決するための手段】透水性が比較的良い砂、
礫地盤の間隙水の中に微細な気泡を混入させることで、
地震時に発生する静水圧より大きい過剰間隙水の発生を
混入気泡の圧縮・圧壊により抑止して液状化を防止する
ことが本発明の第一の課題に対する解決手段である。こ
の場合、改良対象地盤の改良後の均質性、遮水壁等の付
帯工事を必要としないこと、改良工事範囲の外側で工事
ができるようにすることで共用しながらでも工事ができ
るようにするため、工事範囲外側の一方に排水井を設
け、反対側の注水井から空気溶解水を圧入する手法で問
題を解決する。Means for Solving the Problems Sand having relatively good water permeability,
By mixing fine bubbles in the pore water of the gravel ground,
The solution to the first problem of the present invention is to prevent the generation of excess pore water larger than the hydrostatic pressure generated during an earthquake by compressing and collapsing bubbles to prevent liquefaction. In this case, the homogeneity of the ground to be improved after the improvement, no additional work such as impermeable walls, etc. are required, and the work can be performed outside the scope of the improvement work, so that the work can be performed while sharing the ground. To solve this problem, a drain well is provided on one side outside the construction area, and air-dissolved water is injected from the injection well on the opposite side.
【0011】本発明はまた水中に土砂を放出して土地を
造成する場合、造成した地盤の間隙水内に気泡を混入さ
せることで、液状化防止を行うもので、土砂の放出時、
その下方に導管から空気溶解水、または圧縮空気を下向
きに放出し土砂を急速に沈降させて気泡まじりの水中に
堆積させることで、自然沈降堆積法よりも密で間隙に気
泡を内包する地盤を造成することで課題を解決しようと
するものである。The present invention also prevents liquefaction by releasing air and sediment into water to create land by mixing air bubbles into pore water of the formed ground.
Below that, air-dissolved water or compressed air is released downward from the conduit, sediment is rapidly settled, and it is deposited in water mixed with air bubbles, so that the ground that contains air bubbles in the gaps is denser than the natural sedimentation method. The goal is to solve the problem by creating.
【0012】また本発明によれば前記の2手段同様、空
気溶解高圧水を注入し圧力開放により気泡を発生させる
ことで、透水性を小さくさせ、間隙水圧を低減させるこ
とができる。According to the present invention, similarly to the above-mentioned two means, by injecting air-dissolved high-pressure water and generating bubbles by releasing the pressure, the water permeability can be reduced and the pore water pressure can be reduced.
【0013】更に本発明は空気溶解高圧水を湖沼等の底
付近から噴出させることで空気でほぼ飽和状態の水に置
換し、過飽和になった余剰の空気は気泡となって排出さ
れることを手段とする。この手法では、高圧水を噴出す
ることで攪拌による改良後の水質の均質化も可能であるFurther, the present invention provides a method in which air-dissolved high-pressure water is ejected from the vicinity of the bottom of a lake or the like to replace air with substantially saturated water, and excess saturated air is discharged as air bubbles. Means. With this method, it is also possible to homogenize the water quality after improvement by stirring by jetting high-pressure water.
【0014】地盤の間隙水の気泡混入量は、地下水の流
動その他の原因で気泡の一部が長期間では消滅する可能
性が危惧される。そこで気泡混入率(飽和度)をモニター
する必要があり、原位置で疎密波(P波)速度や比抵抗等
を高精度で測定して管理する手法が必要になる。It is feared that the amount of air bubbles mixed in the pore water in the ground may partly disappear for a long period of time due to the flow of groundwater and other causes. Therefore, it is necessary to monitor the bubble mixing ratio (saturation degree), and a method of measuring and managing the compression wave (P wave) velocity, the specific resistance, and the like at the original position with high accuracy is required.
【0015】[0015]
【作用】室内での各種の実験の結果、間隙水中に気泡を
混入させて飽和度を低下させると確実に液状化強度は大
きくなること、地盤空隙の飽和度と疎密波速度の関係は
飽和度が低下するほど(空気含有率が高いほど)疎密波
速度が遅くなることは立証されている(文献例:1999地
盤工学会シンポジウム P波速度を用いた不飽和砂の液
状化抵抗の評価 黄ほか)。また、地盤の空隙に空気が
混入して(間隙水中の空気含有)飽和度が低下すると透水
係数が減少することも実験的に立証されている(文献
例:1996地盤工学会シンポジウム 不飽和砂質土の浸透
特性吐水分保持特性 榎本ほか)。以上のように、原理
は既に立証されているが、空気などの気体を原位置の水
圧より高圧下で水に溶解させてから注入することで、微
細な気泡、空気を混入した水質、間隙流体に変化させる
ことが可能になった。その結果、液状化強度の増加をは
じめとする前述の課題を解決することが可能になる。[Function] As a result of various experiments in the room, the liquefaction strength is surely increased when the saturation is lowered by mixing bubbles in the pore water, and the relationship between the saturation of the ground gap and the compression wave velocity is the saturation. It has been proved that the compression wave velocity decreases as the air pressure decreases (the air content rate increases) (Reference example: 1999 Geotechnical Society Symposium Evaluation of liquefaction resistance of unsaturated sand using P-wave velocity Yellow et al. ). In addition, it has been experimentally proved that the permeability decreases when the degree of saturation decreases due to the incorporation of air into the voids in the ground (air content in the pore water) (Reference example: 1996 Geotechnical Society Symposium Unsaturated sandy material) Enomoto et al.) As described above, the principle has already been proved, but by dissolving gas such as air in water at a pressure higher than the in-situ water pressure and then injecting it, fine bubbles, water quality mixed with air, pore fluid It became possible to change to. As a result, it is possible to solve the above-described problems including an increase in liquefaction strength.
【0016】飽和度が低くなると比抵抗が大きくなるこ
とも既に確認されている(文献例:1996地盤工学会 不
飽和地盤における透水性評価に関する現状分析 )。こ
の原理を利用することで目的の達成度を管理できること
になる。It has already been confirmed that the specific resistance increases as the degree of saturation decreases (reference example: 1996 Geotechnical Society, Analysis of current state of water permeability evaluation in unsaturated ground). By using this principle, it is possible to manage the degree of achievement of the purpose.
【0017】[0017]
【実施例】空気溶解高圧水を発生させる装置は既に実用
化されている。例えば、(株)ニクニ渦流ポンプ資料:渦
流タービンポンプを用いて、溶けにくい液体同士、液体
と気体を混合融解し、タンク等に放出して、廃液を分離
したりミルキーバス等に利用されている。DESCRIPTION OF THE PREFERRED EMBODIMENTS A device for generating air-dissolved high-pressure water has already been put to practical use. For example, Nikuni swirl pump material: Using a swirl turbine pump, a mixture of hardly soluble liquids or a mixture of liquid and gas is melted and discharged to a tank, etc., and is used for separating waste liquid or for a milky bath. .
【0018】図1は、液状化防止対象地盤に空気溶解高
圧水を注入して、自然地下水と置換することで地盤の間
隙に微細な気泡を発生させて液状化強度の増加を図る実
証モデルの概要を示したものである。建屋構造物(1)は
第一地層(2)に直接基礎で支持されており、第二地層(3)
は中位の締まりを有する飽和砂層で地下水位(5)は建屋
基礎下面付近にある。第三地層(4)は強固な地盤からな
る。建屋側面に沿って第一地層を貫通する排水パイプ(1
0)とその下部に接続された第二地層下面に達する排水ス
トレーナーパイプ(11)を設置して排水ポンプ(6)で揚水
し、タンク(7)で一旦貯留し、連結ホース(8)を介して、
空気溶解高圧水発生装置(9)で出力水の圧力調節を行
い、第一地層を貫通する注水パイプ(12)の頭部から注水
する。注水パイプ下端部に接続された第二地層下端部に
達する注水ストレーナーパイプ(13)から高圧水を注入す
る。FIG. 1 shows a demonstration model for increasing the liquefaction strength by injecting air-dissolved high-pressure water into the liquefaction prevention ground and replacing it with natural groundwater to generate fine bubbles in the gaps between the grounds. This is an overview. The building structure (1) is directly supported on the first stratum (2) on the foundation, and the second stratum (3)
Is a saturated sand layer with moderate confinement and the groundwater level (5) is near the bottom of the building foundation. The third formation (4) consists of strong ground. A drainage pipe (1
0) and a drainage strainer pipe (11) connected to the lower surface of the second formation connected to the lower part, and pumped up by a drainage pump (6), temporarily stored in a tank (7), and connected via a connecting hose (8). hand,
The pressure of the output water is adjusted by the air-dissolved high-pressure water generator (9), and water is injected from the head of a water injection pipe (12) penetrating the first formation. High-pressure water is injected from the water injection strainer pipe (13) reaching the lower end of the second formation connected to the lower end of the water injection pipe.
【0019】自然地下水は、排水ストレーナーパイプ(1
1)に向かって建屋下と外側の第二地層から流入する。一
方、注水ストレーナー(13)からは建屋周辺にも空気溶解
高圧水が流出されるが、建屋の反対側に設置してある排
水ストレーナーからの排水により自然水圧が低下するた
め、より多くの空気溶解水が流れ建屋直下の第二地層内
の間隙は自然水が空気溶解水で置換され、自然水圧に減
圧した定常状態では微細気泡が発生する。図示の矢印
は、建屋外側からの流入自然地下水(14)、建屋直下流入
地下水(15)、建屋外側注入空気溶解水(17)、建屋直下注
入空気溶解水(16)を示すNatural groundwater is drained strainer pipes (1
It flows from the second stratum below and outside the building toward 1). On the other hand, air-dissolved high-pressure water also flows out of the building from the water injection strainer (13), but the natural water pressure drops due to drainage from the drainage strainer installed on the opposite side of the building, so more air-dissolved water is released. In the gap in the second formation immediately below the building, the natural water is replaced by air-dissolved water, and fine bubbles are generated in a steady state where the pressure is reduced to the natural water pressure. Arrows shown in the figure indicate natural groundwater flowing in from the building exterior side (14), groundwater flowing in directly under the building (15), dissolved air dissolved water outside the building (17), and dissolved air dissolved directly below the building (16).
【0020】建屋直下の自然間隙水が空気溶解水により
置換された状態で、排水パイプ(10)からも空気溶解高圧
水を注入して建屋周辺の第二地層の間隙にも微細気泡を
発生させることで建屋直下とその周辺地盤を改良するこ
とが可能となる。In a state in which the natural pore water immediately below the building is replaced by air-dissolved water, air-dissolved high-pressure water is also injected from the drainage pipe (10) to generate fine bubbles also in the gap in the second formation around the building. This makes it possible to improve the ground immediately below the building and the surrounding ground.
【0021】また、図1において、注水ストレーナーパ
イプ(13)を、例えば千鳥状に近接して設置し、空気溶解
高圧水を注入して気泡帯を壁状に造成することで透水性
を1桁程度低下させることができ、掘削工事などに適用
することで排水量を低減し、かつ抗土圧構造物に作用す
る外力を小さくすることができる。本工法では地盤間隙
内にほぼ連続した気泡群を造成する必要があるので、注
入水圧をより高圧にして静水圧に戻したときの過飽和空
気量を多くしてより多くの気泡を発生させるようにす
る。In FIG. 1, a water injection strainer pipe (13) is installed, for example, in a staggered manner, and air-dissolved high-pressure water is injected to form a bubble zone into a wall, thereby increasing water permeability by one digit. It is possible to reduce the amount of drainage by applying to excavation work and the like, and to reduce the external force acting on the anti-earth pressure structure. In this construction method, it is necessary to create a group of substantially continuous bubbles in the ground gap.Therefore, when the injection water pressure is increased to a higher value and returned to the hydrostatic pressure, the amount of supersaturated air should be increased to generate more bubbles. I do.
【0022】図2は、図1モデルの間隙水圧の分布を示す
もので、排水・注水を行う前の静水圧分布(18、自然間
隙水圧分布)から排水後の定常状態を想定した排水後低
下水圧分布(19)状態になった時点で、空気溶解高圧水発
生装置(9)の出力ゲージ圧(20)で注水すると、注水時水
圧分布(21)になり、静水圧と注水圧との差圧(23)、排水
後水圧と注水圧との差圧(22)は共に深度方向に夫々ほぼ
同じ水圧差となり、この水圧差で注水されることにな
る。FIG. 2 shows the distribution of pore water pressure of the model shown in FIG. 1. The distribution of hydrostatic pressure before drainage / water injection (18, natural pore water pressure distribution) shows a drop after drainage assuming a steady state after drainage. At the time of the water pressure distribution (19), if water is injected at the output gauge pressure (20) of the air-dissolved high-pressure water generator (9), the water pressure distribution at the time of water injection becomes (21), and the difference between the hydrostatic pressure and the water injection pressure is obtained. Both the pressure (23) and the pressure difference (22) between the post-drain water pressure and the water injection pressure are substantially the same in the depth direction, and water is injected at this water pressure difference.
【0023】以上の水圧分布は、地盤の透水性、排水や
注水量、経過時間等により異なるが、おおむね同じ差圧
で注水され、注水ストレーナーパイプからの距離が大き
くなるに連れて流体抵抗により注水圧は低下し、その低
下水圧に応じて過飽和空気が微細な泡となる。排水・注
水を停止すると静止水圧分布になり、注水ストレーナー
付近も微細な泡で間隙が充填されることになる。The above water pressure distribution varies depending on the permeability of ground, drainage and water injection amount, elapsed time, and the like. However, the water is injected at substantially the same differential pressure, and as the distance from the water injection strainer pipe increases, the water pressure distribution increases. The water pressure decreases, and the supersaturated air becomes fine bubbles according to the reduced water pressure. When the drainage / water injection is stopped, the water pressure distribution becomes static, and the space near the water injection strainer is also filled with fine bubbles.
【0024】図3は、水中に土砂を放出して埋立てる作
業時に、水中に圧縮空気あるいは空気を溶解した高圧水
を噴射して空気混入水にした状態で埋立てを行う工法の
検証モデルに関するものである。運搬船等から懸架した
射出ホース(25)の先端部付近には水噴射口とその噴射反
力に抗するためのウェイト・噴射口(26)を有し、この先
端を地盤面(30)近くまで降し、圧縮空気あるいは空気溶
解高圧水を下方に噴射させながら土砂を運搬船(24)等か
ら水中に放出する。射出ホースは船上などで巻き取り、
先端部が常に新規埋立地盤の上方近くに位置するように
する。FIG. 3 shows a verification model of a construction method in which landfill is performed in a state where compressed air or high-pressure water in which air is dissolved is injected into water to form aerated water during a landfill operation by discharging earth and sand into water. Things. In the vicinity of the tip of the injection hose (25) suspended from a carrier, etc., there is a water injection port and a weight / injection port (26) to resist the injection reaction force, and this tip extends to near the ground surface (30). It descends and discharges the earth and sand from the carrier (24) or the like while injecting the compressed air or the high pressure water dissolved in the air downward. The injection hose is wound up on a ship,
Ensure that the tip is always near the top of the new landfill.
【0025】放出土砂(29)は、上昇気泡(28)を巻き込
みながら沈降し、新規埋立地盤の上方近くでは噴射口か
らの下向きの噴射流(27)により沈降を促進し、静水圧に
なった時点では微細気泡を混入した間隙流体を有するよ
り密な埋立地盤を造成することが可能ととなる。The released sediment (29) settles while entraining the rising air bubbles (28), and near the upper part of the new landfill, the sedimentation was promoted by the downward jet flow (27) from the injection port, and the hydrostatic pressure was increased. At this point, it becomes possible to create a denser landfill bed with interstitial fluid mixed with fine bubbles.
【0026】図4は、湖沼等の水質を改良するため、空
気溶解高圧水を水中に吐出させて溶存酸素量の適正化、
水質の均質化を目的とする工法の検証モデルに関するも
のである。水質が悪化している湖沼などは、成層状態が
進行し、浅部の暖かい表層(31)とその下の冷たい底層(3
2)に別れ底層は無酸素状態となる。このような状態を解
消するため、湖底相当地盤に注水ホースを敷設、あるい
は更に効率を高めるため底層の冷水を湖面近くに導き周
囲の温度で暖めながら注水できるように注水・サクショ
ンホース(33)の2系統のホースを敷設する。FIG. 4 shows that in order to improve the quality of water in lakes and marshes, air dissolved high pressure water is discharged into water to optimize the amount of dissolved oxygen.
It relates to a verification model of a construction method aimed at homogenizing water quality. In lakes and marshes where the water quality is deteriorating, stratification progresses, and the shallow warm surface layer (31) and the cold bottom layer (3
2) The bottom layer becomes anoxic. In order to eliminate such a situation, a water injection hose is laid on the ground equivalent to the lake bottom, or a water injection / suction hose (33) is installed so that cold water in the bottom layer can be guided near the lake surface and heated at ambient temperature to further increase efficiency. Lay two hoses.
【0027】ホースの複数カ所に伸縮性(張力が働くと
伸びる)の吐出ホース(34)を接続する。この吐出ホース
の上端部にはフロート兼射水ノズル(35)があり、射水方
向と射水量を設定できるようになっている。また、吐出
ホースの根元近くにはサクションホースの給水口(36)が
取り付けてある。サクションホースは湖面に設置した受
水プール(38)の底に接続され、この受水プールに貯めた
深層冷水は暖められ、空気溶解高圧水発生装置(9)によ
り吸い込み、高圧下で空気を溶解し注水ホースに送り込
まれ、吐出ホースの噴射ノズルから射水して湖水を攪拌
し、微細な気泡(37)となって水中を浮遊しながら上昇す
る。An elastic (expandable when tension is applied) discharge hose (34) is connected to a plurality of locations of the hose. At the upper end of the discharge hose, there is a float / spray nozzle (35), so that the direction and amount of spray can be set. A suction hose water inlet (36) is attached near the base of the discharge hose. The suction hose is connected to the bottom of the water receiving pool (38) installed on the lake surface, the deep cold water stored in this water receiving pool is warmed, sucked by the air dissolving high pressure water generator (9), and melts the air under high pressure The water is then fed into the water injection hose, and is sprayed from the injection nozzle of the discharge hose to agitate the lake water, forming fine bubbles (37) and rising while floating in the water.
【0028】注水圧力を高くすると噴射ノズル部の抵抗
で吐出ホース(34)は伸びて浅部で射水できるようになっ
ているので送水圧を適宜変動させて攪拌することにより
水質の均質化の促進を図れるようになっている。When the injection pressure is increased, the discharge hose (34) is extended by the resistance of the injection nozzle portion so that water can be sprayed at a shallow portion. Can be planned.
【0029】この工法は、水に空気を溶解させるもので
あるが、空気の他に動植物に必要な栄養素等や環境劣化
要因の中和剤等を溶解して注水することで湖沼、河川、
海水、養殖場等の環境改善を行うことが可能である。In this method, air is dissolved in water, but in addition to air, nutrients and the like necessary for animals and plants and neutralizing agents for environmental degradation are dissolved and injected into a lake, river, or river.
It is possible to improve the environment of seawater, farms, etc.
【0030】[0030]
【発明の効果】水質を改良しようとする原位置の水圧よ
り高圧下で空気を溶解させた飽和状態の水を注入し、原
位置の静水圧になると微細な気泡を有する流体となり、
気泡は土粒子の骨格により自由な移動ができないため、
気泡を含有した圧縮性の高い間隙流体とすることができ
るため、液状化抵抗を効率的に増加させることができ
る。According to the present invention, saturated water in which air is dissolved is injected under a higher pressure than the in-situ water pressure to improve the water quality, and when the in-situ hydrostatic pressure is reached, a fluid having fine bubbles is formed,
Since bubbles cannot move freely due to the skeleton of soil particles,
Since a highly compressible gap fluid containing air bubbles can be obtained, the liquefaction resistance can be efficiently increased.
【0031】この工法の間隙中の気泡の含有率を多くす
ることで地盤の透水性を小さくし水圧を軽減できる。ま
た、粒状体土砂で埋立造成を行う過程で、間隙水に気泡
を混入させることで上記同様の液状化強度の増加を図る
ことができること、これらの工法の信頼性のチェックを
疎密波速度や地盤の比抵抗から行うことができることが
判った。By increasing the content of bubbles in the gaps in this method, the water permeability of the ground can be reduced and the water pressure can be reduced. Also, in the process of landfilling with granular sediment, it is possible to increase the liquefaction strength as described above by mixing bubbles in pore water, and to check the reliability of these methods for compression wave velocity and ground It can be seen that the specific resistance can be obtained.
【0032】同様な手法で湖沼等の水質の改善を効果的
に図ることができ、かつ積極的に水質を好環境に変換す
ることで動植物の生育促進などに役立てられる。The water quality of lakes and marshes can be effectively improved by a similar method, and the water quality can be positively converted into a favorable environment to promote the growth of animals and plants.
【0033】[0033]
【図1】液状化防止対象地盤に空気溶解高圧水を注入し
て、自然地下水と置換することで地盤の間隙に微細な気
泡を発生させて液状化強度の増加を図る実証モデルの概
要を示したものである。Fig. 1 shows an outline of a demonstration model that increases the liquefaction strength by injecting air-dissolved high-pressure water into the liquefaction prevention ground and replacing it with natural groundwater to generate fine bubbles in the gaps between the grounds. It is a thing.
【図2】図1モデルの間隙水圧の分布を示すものであ
る。FIG. 2 shows a distribution of pore water pressure in the model of FIG. 1;
【図3】水中に土砂を放出して埋立てる作業時に、水中
に圧縮空気あるいは空気を溶解した高圧水を噴射して空
気混入水にした状態で埋立てを行う工法の検証モデルに
関するものである。FIG. 3 relates to a verification model of a construction method in which landfill is performed in a state in which compressed air or high-pressure water in which air is dissolved is injected into water to form an aerated water during landfill work by discharging earth and sand into water. .
【図4】湖沼等の水質を改良するため、空気溶解高圧水
を水中に吐出させて溶存酸素量の適正化、水質の均質化
を目的とする工法の検証モデルに関するものである。FIG. 4 relates to a verification model of a construction method for discharging dissolved high-pressure water into water to optimize the amount of dissolved oxygen and to homogenize the water quality in order to improve the water quality of lakes and the like.
1 建屋構造物 2 第一地層 3 第二地層 4 第三地層 5 地下水位 6 排水ポンプ 7 タンク 8 連結ホース 9 空気溶解高圧水発生装置 10 排水パイプ 11 排水ストレーナーパイプ 12 注水パイプ 13 注水ストレーナーパイプ 14 流入自然地下水 15 建屋直下流入地下水 16 建屋直下注入空気溶解水 17 建屋外側注入空気溶解水 18 静水圧分布 19 排水後低下水圧分布 20 出力ゲージ圧 21 注水時水圧分布 22 排水後水圧と注水圧との差圧 23 静水圧と注水圧との差圧 24 運搬鉛 25 射出ホース 26 ウエイト・噴射口 27 噴射流 28 上昇気泡 29 放出土砂 30 地盤面 31 表層 32 底層 33 注水・サクションホース 34 吐出ホース 35 フロート兼射水ノズル 36 給水口 37 気泡 38 受水プール DESCRIPTION OF SYMBOLS 1 Building structure 2 1st formation 3 2nd formation 4 3rd formation 5 Groundwater level 6 Drain pump 7 Tank 8 Connecting hose 9 Air dissolving high-pressure water generator 10 Drainage pipe 11 Drainage strainer pipe 12 Water injection pipe 13 Water injection strainer pipe 14 Inflow Natural groundwater 15 Groundwater inflow directly below the building 16 Dissolved air dissolved water directly below the building 17 Dissolved air dissolved water outside the building 18 Hydrostatic pressure distribution 19 Decreased water pressure distribution after drainage 20 Output gauge pressure 21 Water pressure distribution during water injection 22 Difference between water pressure after injection and injection pressure Pressure 23 Differential pressure between hydrostatic pressure and injection pressure 24 Lead transported 25 Injection hose 26 Weight / injection port 27 Injection flow 28 Upward air bubble 29 Ejected sand 30 Ground surface 31 Surface layer 32 Bottom layer 33 Water injection / suction hose 34 Discharge hose 35 Floating / spray Nozzle 36 Water inlet 37 Bubble 38 Water receiving pool
Claims (5)
高い圧力で空気を溶解した水を注入して地下水と置換
し、水圧が静水圧に低下して溶解空気が過飽和状態にな
り微細な気泡が発生することで、空隙流体の体積圧縮率
を小さくすることを特徴とする液状化防止工法。1. A method in which water in which air is dissolved at a pressure higher than the groundwater pressure is injected into the ground under the groundwater to replace the groundwater, and the water pressure is reduced to a hydrostatic pressure, and the dissolved air becomes supersaturated and becomes fine. A liquefaction-prevention method characterized in that the volume compression ratio of the void fluid is reduced by generating fine bubbles.
水中に圧縮空気あるいは空気を溶解した高圧水を噴射
し、空気混入水にした状態で埋立てを行うことを特徴と
する地盤改良工法。2. The method of discharging earth and sand into water and reclaiming the land.
A ground improvement method characterized by injecting compressed air or high-pressure water in which air is dissolved into water, and performing landfilling in the state of aerated water.
に連続した気泡の塊を作ることで地下水の流動抵抗の増
加と水圧の低下を図ることを特徴とする地盤改良工法。3. A ground improvement method comprising repeating the steps of claim 1 to increase the flow resistance of groundwater and lower the water pressure by forming continuous air bubbles in the void fluid.
圧より高い圧力で空気を溶解した水を吐出することで溶
存酸素量の適正化と攪拌による水質の均質化を図ること
を特徴とする水質改良工法。4. In order to improve the quality of water in lakes and marshes, water dissolved in air is discharged at a pressure higher than the water pressure of lakes and marshes, whereby the amount of dissolved oxygen is optimized and the water quality is homogenized by stirring. Water quality improvement method.
隙流体内の気体の体積含有率を測定するため、疎密波速
度測定、或は比抵抗測定を行って地盤の飽和度を管理す
ることを特徴とする施工管理工法。5. The method according to claim 1, wherein the degree of saturation of the ground is controlled by measuring compressional wave velocity or specific resistance in order to measure the volume content of gas in the interstitial fluid. Construction management method characterized by doing.
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JP2000004780A JP4026739B2 (en) | 2000-01-13 | 2000-01-13 | Ground improvement method by gas dissolved water injection |
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Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007046408A (en) * | 2005-08-12 | 2007-02-22 | Takenaka Komuten Co Ltd | Ground improvement evaluation device, ground improvement evaluation method and ground improvement evaluation program |
JP2008038511A (en) * | 2006-08-08 | 2008-02-21 | Taisei Corp | Pile foundation reinforcing structure |
JP2009222668A (en) * | 2008-03-18 | 2009-10-01 | Ritsumeikan | Method for estimating oil contamination distribution of soil and applying result thereof to bioremediation |
JP2014005612A (en) * | 2012-06-22 | 2014-01-16 | Maeda Corp | Quality confirmation method and quality confirmation device for improved ground |
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JP5458332B1 (en) * | 2013-03-04 | 2014-04-02 | 強化土株式会社 | Ground improvement method |
JP5467233B1 (en) * | 2013-03-04 | 2014-04-09 | 強化土株式会社 | Ground improvement method |
JP2014221969A (en) * | 2013-05-13 | 2014-11-27 | 鹿島建設株式会社 | Soil desaturation system and soil improvement method |
KR101855804B1 (en) * | 2016-09-07 | 2018-06-25 | 주식회사 지오그린21 | Hybrid well system for a water curtain house and method of alternatively injecting oxygen water using the same |
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2000
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Cited By (10)
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JP2007046408A (en) * | 2005-08-12 | 2007-02-22 | Takenaka Komuten Co Ltd | Ground improvement evaluation device, ground improvement evaluation method and ground improvement evaluation program |
JP4704848B2 (en) * | 2005-08-12 | 2011-06-22 | 株式会社竹中工務店 | Ground improvement evaluation device and ground improvement evaluation program |
JP2008038511A (en) * | 2006-08-08 | 2008-02-21 | Taisei Corp | Pile foundation reinforcing structure |
JP2009222668A (en) * | 2008-03-18 | 2009-10-01 | Ritsumeikan | Method for estimating oil contamination distribution of soil and applying result thereof to bioremediation |
JP2014005612A (en) * | 2012-06-22 | 2014-01-16 | Maeda Corp | Quality confirmation method and quality confirmation device for improved ground |
JP5458332B1 (en) * | 2013-03-04 | 2014-04-02 | 強化土株式会社 | Ground improvement method |
JP5467233B1 (en) * | 2013-03-04 | 2014-04-09 | 強化土株式会社 | Ground improvement method |
JP2014221969A (en) * | 2013-05-13 | 2014-11-27 | 鹿島建設株式会社 | Soil desaturation system and soil improvement method |
CN103628465A (en) * | 2013-11-15 | 2014-03-12 | 河海大学 | Device and method for circulating water discharging blocking prevention through exhausting and inflating sludge |
KR101855804B1 (en) * | 2016-09-07 | 2018-06-25 | 주식회사 지오그린21 | Hybrid well system for a water curtain house and method of alternatively injecting oxygen water using the same |
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Free format text: JAPANESE INTERMEDIATE CODE: R250 |
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LAPS | Cancellation because of no payment of annual fees |