JPS6312514B2 - - Google Patents
Info
- Publication number
- JPS6312514B2 JPS6312514B2 JP58071260A JP7126083A JPS6312514B2 JP S6312514 B2 JPS6312514 B2 JP S6312514B2 JP 58071260 A JP58071260 A JP 58071260A JP 7126083 A JP7126083 A JP 7126083A JP S6312514 B2 JPS6312514 B2 JP S6312514B2
- Authority
- JP
- Japan
- Prior art keywords
- silica sol
- ground
- gelation time
- acidic
- water glass
- 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.)
- Expired
Links
- 238000001879 gelation Methods 0.000 claims description 24
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 23
- 230000002378 acidificating effect Effects 0.000 claims description 20
- 238000002347 injection Methods 0.000 claims description 16
- 239000007924 injection Substances 0.000 claims description 16
- 235000019353 potassium silicate Nutrition 0.000 claims description 13
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- 239000003673 groundwater Substances 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 239000000499 gel Substances 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000003814 drug Substances 0.000 description 3
- 229940079593 drug Drugs 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Description
この発明は軟弱地盤等の地盤改良を行なう酸性
シリカゾルを用いた地盤注入工法に関する。
従来水ガラスを用いた地盤注入工法すなわち、
水ガラスに直接反応剤を添加しゲル化せしめる方
法が一般に採用されていた。この方法によると水
ガラスそのものが高アルカリ性であり、PHが弱ア
ルカリ性の領域でゲル化するため、固結体も通常
PH12〜10のアルカリ性を示す。このため注入地盤
の地下水をアルカリ性にし問題となつた。また、
ゲル中に未凝固の水ガラスが残存し、これが溶出
して長期的に性能が低下するという問題があつ
た。
このような問題点に対処し、近年は水ガラスを
酸で処理し、非アルカリまたは酸性シリカゾル液
となし地盤に注入する工法が注目を注びている。
非アルカリ性のシリカゾルは地下水による希釈の
有無にかかわらず必ずゲル化し、地下水面下での
固結が優れ、配合時点で酸性であつても固結土や
地下水のPHに殆んど影響を与えず、ゲル化物は長
期間に高強度となる長所がある。しかし非アルカ
リ性シリカゾルはゲル化する条件範囲が狭く、安
定した作業条件で地盤改良を行い難かつた。
すなわち、非アルカリ性シリカゾルのPHとゲル
化時間との関係は図面グラフのごとくであり通常
PH２〜５の範囲のシリカゾルに、注入に先だつて
アルカリ性の金属塩等の硬化剤を加えてPHを調整
してゲル化を促進させるものである。しかし、こ
のことは図からも明らかなように、ゲル化時間は
PHに極めてシヤープである。例えばPH３〜PH４の
間でゲル化時間は数時間から２〜３分の範囲まで
変動する。また、本発明者らの実験によると、塩
化アルミニウム（AlCl36H2O）、硫酸マグネシウ
ム（MgSO4）等は非アルカリ性シリカゾルのゲ
ル化時間を短縮せしめることはできなかつた。ゲ
ル化時間はPHのほか、シリカ濃度、液温、地下水
の状態等の条件の影響を受けるので注入現場にお
いて、注入薬剤のゲル化時間を適正に保つことは
むずかしく、薬剤を地盤内に充分浸透せしめゲル
化させる上で問題となつていた（参考文献特開昭
53−13630号公報参照）。
この発明は上記問題点に着目しなされたもの
で、その目的は、ゲル化時間を自由に、かつ安定
して調整ができ、欠陥部がなく、環境汚染を起す
恐れがない酸性シリカゾルの地盤注入工法を提案
するにある。その要旨は水ガラスを酸性液中に混
入してなつた酸性シリカゾルを地盤に注入して地
盤を固結せしめる地盤注入工法において、前記酸
性シリカゾルのPHを１〜４となし、ポリ塩化アル
ミニウムを添加しゲル化時間を制御することを特
徴とする酸性シリカゾルの地盤注入工法である。
この工法においては、主材としてPH１〜４の酸
性シリカゾルを用い、ポリ塩化アルミニウム（以
下PACと略称する）を添加してゲル化時間を制
御する。PAC添加量とゲル化時間の関係は、PH
とゲル化時間の関係に比べ、緩慢であり、通常要
求される10分〜２時間程度のゲル化時間に自由に
調整できる。
PACの一般式は〔Al2（OH）oCl6-o〕n、１≦ｎ≦
５、ｍ≦10、塩基度＝ｎ／６×100％（45〜65％）で
ある。通常、Al2O3換算10〜11％の水溶液を原料
とする。酸性シリカゾルの主材にPACを添加す
る時期は、注入に先じて添加混合しても、別々の
管で注入位置に送る途中で管を合流して混合して
も、あるいは注入管の先端で合流混合してもよ
い。
酸性シリカゾルのPHは１〜４でありより好まし
くは１〜３である。PH４以上となるとPH調整がむ
ずかしく、しかもシリカゾルのゲル化時間が短く
なり好ましくない。また酸性シリカゾルは市販さ
れている水ガラス（例えばJIS3号品あるいはモル
比（SiO2／Na2O）２〜４の水ガラス）を原料と
し、これを酸性液に混入してPH１〜４となし得ら
れる。地盤注入薬剤中の酸性シリカゾルの濃度は
原料水ガラスをベースにして15〜50容積％（３号
水ガラスの場合SiO2濃度６％〜20％）が好適で
ある。これ以上濃度が高いとゲル化時間が短くな
り不安定となり好ましくない。また濃度があまり
低下すると地盤を強固に固結できなくなり好まし
くない。酸性シリカゾル液にPAC液を添加して
なつた地盤注入薬剤中のPAC濃度はAl2O3換算10
％濃度のPACをベースにして５〜30容積％とす
ることによつて、地盤注入薬剤のゲル化時間を数
分〜数時間の範囲に調整することができる。
（実施例）
酸性シリカゾル液（Ａ液）：SiO2／Na2O、モ
ル比3.76の水ガラス50を硫酸水溶液中に
撹拌しつつ混入し、PH1.6、全液量を100
に調製した。
PAC液（Ｂ液）：Al2O3換算10％、PH3.5〜5.0の
PAC16，18，20，22にそれぞれ
水を加えて全量を100となした。
上記Ａ液とＢ液とを等容量づつ混合し、水ガラ
スベース濃度25容積％PAC10％液ベース濃度７，
８，９，10，11容積％の地盤注入薬剤を調製し
た。この薬剤のゲル化時間を表―１に示す。この
表から明らかなように種々の練おき時間のもと
で、注入薬剤のゲル化時間を10分〜数時間の間に
自由に調整できる。
The present invention relates to a ground injection method using acidic silica sol for improving soft ground and the like. Conventional ground injection method using water glass, that is,
A commonly used method was to add a reactant directly to water glass to form a gel. According to this method, the water glass itself is highly alkaline and gels in the weakly alkaline pH range, so the solids are usually
Shows alkalinity with a pH of 12 to 10. This caused the groundwater in the injection site to become alkaline, which became a problem. Also,
There was a problem in that unsolidified water glass remained in the gel, and this dissolved out, resulting in a long-term decline in performance. To address these problems, in recent years, a method of treating water glass with acid and injecting it into the ground as a non-alkaline or acidic silica sol has been attracting attention.
Non-alkaline silica sol always gels regardless of whether it is diluted with groundwater, solidifies well under the groundwater table, and has almost no effect on the PH of compacted soil or groundwater even if it is acidic at the time of formulation. The gelled material has the advantage of maintaining high strength over a long period of time. However, non-alkaline silica sol has a narrow range of gelling conditions, making it difficult to improve the ground under stable working conditions. In other words, the relationship between the PH and gelation time of non-alkaline silica sol is as shown in the graph, and is usually
A curing agent such as an alkaline metal salt is added to silica sol having a pH of 2 to 5 prior to injection to adjust the pH and promote gelation. However, as is clear from the figure, the gelation time is
The pH is extremely sharp. For example, gelation time varies from several hours to 2 to 3 minutes between PH3 and PH4. Furthermore, according to experiments conducted by the present inventors, aluminum chloride (AlCl 3 6H 2 O), magnesium sulfate (MgSO 4 ), and the like were unable to shorten the gelation time of non-alkaline silica sol. In addition to pH, gelation time is affected by conditions such as silica concentration, liquid temperature, and groundwater conditions, so it is difficult to maintain an appropriate gelation time for the injected chemical at the injection site, and it is difficult to ensure that the chemical penetrates sufficiently into the ground. This was a problem in gelatinization (Reference JP-A-Sho).
(See Publication No. 53-13630). This invention was made in view of the above-mentioned problems, and its purpose is to inject acidic silica sol into the ground, which allows the gelation time to be freely and stably adjusted, has no defects, and is free from the risk of causing environmental pollution. We are proposing construction methods. The gist is that in the ground injection method, the acidic silica sol produced by mixing water glass into an acidic liquid is injected into the ground to solidify the ground.The pH of the acidic silica sol is adjusted to 1 to 4, and polyaluminum chloride is added. This is an acidic silica sol injection method that is characterized by controlling the gelation time. In this method, acidic silica sol with a pH of 1 to 4 is used as the main material, and polyaluminum chloride (hereinafter abbreviated as PAC) is added to control the gelation time. The relationship between the amount of PAC added and gelation time is determined by the pH
The gelation time is slow compared to the relationship between the gelation time and the gelation time, and the gelation time can be freely adjusted to the normally required gelation time of about 10 minutes to 2 hours. The general formula of PAC is [Al 2 (OH) o Cl 6-o ] n , 1≦n≦
5, m≦10, basicity = n/6×100% (45-65%). Usually, the raw material is an aqueous solution containing 10 to 11% Al 2 O 3 . The timing of adding PAC to the main material of acidic silica sol is determined by whether it is added and mixed before injection, whether it is mixed by merging the tubes while being sent to the injection position in separate tubes, or at the tip of the injection tube. They may be mixed together. The acidic silica sol has a pH of 1 to 4, preferably 1 to 3. If the pH is higher than 4, it will be difficult to adjust the pH, and the gelation time of the silica sol will be shortened, which is not preferable. Acidic silica sol is made from commercially available water glass (e.g., JIS No. 3 or water glass with a molar ratio (SiO 2 /Na 2 O) of 2 to 4) and is mixed into an acidic liquid to adjust the pH to 1 to 4. can get. The concentration of acidic silica sol in the ground injection agent is preferably 15 to 50% by volume (in the case of No. 3 water glass, the SiO 2 concentration is 6% to 20%) based on the raw water glass. If the concentration is higher than this, the gelation time becomes short and becomes unstable, which is not preferable. Also, if the concentration decreases too much, it will not be possible to solidify the ground, which is undesirable. The PAC concentration in the ground injection agent obtained by adding the PAC solution to the acidic silica sol solution is Al 2 O 3 equivalent 10
By adjusting the concentration of PAC to 5 to 30% by volume, the gelation time of the ground injection agent can be adjusted to a range of several minutes to several hours. (Example) Acidic silica sol solution (liquid A): SiO 2 /Na 2 O, 50% water glass with a molar ratio of 3.76 was mixed into an aqueous sulfuric acid solution with stirring, and the pH was 1.6, and the total liquid volume was 100%.
It was prepared as follows. PAC solution (B solution): 10% in terms of Al 2 O 3 , PH 3.5 to 5.0
Water was added to each of PAC16, 18, 20, and 22 to make a total volume of 100. Mix the above A liquid and B liquid in equal volumes, water glass base concentration 25 volume% PAC 10% liquid base concentration 7,
Ground injection chemicals of 8, 9, 10, and 11% by volume were prepared. Table 1 shows the gelation time of this drug. As is clear from this table, the gelation time of the injectable drug can be freely adjusted between 10 minutes and several hours under various kneading times.
【表】
また表―１中のPAC濃度８容積％の注入薬剤
のサンドゲルの剤令と一軸圧縮強度は表―２の通
りであつた。[Table] In addition, the strength and unconfined compressive strength of the sand gel of the injected drug with a PAC concentration of 8% by volume in Table 1 are as shown in Table 2.
【表】
この発明は以上の通りである。この地盤注入工
法はゲル化時間が自由に、しかも正確に制御でき
るので、薬剤を地盤内によく浸透せしめゲル化さ
せることができ、均質な地盤改良が達成できる。
また、アルカリが溶出しないので地下水PHに大き
な影響を及ぼさず、固結土の耐久性も優れてい
る。[Table] The present invention is as described above. This ground injection method allows the gelation time to be controlled freely and accurately, allowing the chemical to penetrate well into the ground and gelate, thereby achieving homogeneous ground improvement.
In addition, since alkali does not elute, it does not have a large effect on groundwater pH, and the compacted soil has excellent durability.
図面はシリカゾルのPHとゲル化時間との相関グ
ラフである。
The figure is a correlation graph between the pH of silica sol and gelation time.
Claims (1)
リカゾルを地盤に注入して固結せしめる地盤注入
工法において、前記酸性シリカゾルのPHを１〜４
となし、ポリ塩化アルミニウムを添加してゲル化
時間を制御することを特徴とする酸性シリカゾル
の地盤注入工法。1 In the ground injection method in which acidic silica sol mixed with water glass in an acidic liquid is injected into the ground and solidified, the pH of the acidic silica sol is set to 1 to 4.
A method for injecting acidic silica sol into the ground, which is characterized by adding polyaluminum chloride to control gelation time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58071260A JPS59196388A (en) | 1983-04-22 | 1983-04-22 | Pouring of acidic silica sol into ground and grout |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58071260A JPS59196388A (en) | 1983-04-22 | 1983-04-22 | Pouring of acidic silica sol into ground and grout |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59196388A JPS59196388A (en) | 1984-11-07 |
| JPS6312514B2 true JPS6312514B2 (en) | 1988-03-19 |
Family
ID=13455570
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58071260A Granted JPS59196388A (en) | 1983-04-22 | 1983-04-22 | Pouring of acidic silica sol into ground and grout |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59196388A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3932562B2 (en) * | 1995-07-06 | 2007-06-20 | 日産化学工業株式会社 | Ground injection agent |
| JP3226510B2 (en) * | 1999-05-20 | 2001-11-05 | 名古屋カレット株式会社 | Ground hardening method |
| JP3714589B2 (en) * | 1999-09-10 | 2005-11-09 | 強化土エンジニヤリング株式会社 | Chemical solution for ground injection |
| JP3714590B2 (en) * | 1999-09-17 | 2005-11-09 | 強化土エンジニヤリング株式会社 | Chemical solution for ground injection |
| JP6764177B1 (en) * | 2019-02-13 | 2020-09-30 | 強化土エンジニヤリング株式会社 | Ground injection material and ground improvement method using it |
-
1983
- 1983-04-22 JP JP58071260A patent/JPS59196388A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59196388A (en) | 1984-11-07 |
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