JP2017172253A - Jet grout method for liquefaction countermeasure - Google Patents
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本発明は、地盤改良工法に関し、特に砂質地盤における液状化を防止するための液状化対策用ジェットグラウト工法に関する。 The present invention relates to a ground improvement method, and more particularly to a liquefaction countermeasure jet grout method for preventing liquefaction in sandy ground.
砂質地盤では大きな地震が発生した際に液状化現象が起こることが予想される。液状化現象は建造物やインフラ等に大きな影響を与えるおそれがあるため、液状化を事前に防ぐ必要がある。 In sandy ground, liquefaction is expected to occur when a large earthquake occurs. Since the liquefaction phenomenon may have a large impact on buildings and infrastructure, it is necessary to prevent liquefaction in advance.
液状化対策のための地盤改良工法としては、通常、薬液注入工法による浸透注入が採用される。しかし、対象地盤の細粒分含有率（Ｆｃ）が２０％以上の場合は慎重な対応が必要であり、４０％以上の場合は浸透工法の適用は不可能であった。 As a ground improvement method for liquefaction countermeasures, osmotic injection by a chemical solution injection method is usually employed. However, when the fine grain content (Fc) of the target ground is 20% or more, careful handling is necessary, and when it is 40% or more, the infiltration method cannot be applied.
細粒分含有率が高い場合はジェットグラウト工法が採用される。しかし、一般的なジェットグラウト工法では材料がセメント系であることから、改良体強度が必要以上に大きくなることや、粘度が大きいために浸透し難く改良範囲がジェット噴射範囲に限定されているという問題があった。また、多量の排泥も発生していた。 When the fine grain content is high, the jet grout method is adopted. However, since the material is cement based in the general jet grouting method, the improved body strength is unnecessarily large, and the improved range is limited to the jet injection range because of its high viscosity and difficult to penetrate. There was a problem. A large amount of mud was also generated.
特許文献1で提案されている地盤固結工法は、セメントを用いないジェットグラウト工法である。スラグとｐＨ９以上のアルカリ材とを主成分とする地盤固結材を用いて地盤の固結を行う地盤固結工法であり、有機質土や粘性土等を改良できるとされている。 The ground consolidation method proposed in Patent Document 1 is a jet grout method that does not use cement. It is a ground consolidation method in which the ground is consolidated using a ground consolidation material mainly composed of slag and an alkali material having a pH of 9 or more, and it is said that organic soil, viscous soil, and the like can be improved.
しかしながら、特許文献１の地盤固結工法は改良体の強度が非常に大きいことから、地盤改良後の掘削等の施工の支障となる場合がある。 However, the ground consolidation method of Patent Document 1 has an extremely large strength of the improved body, which may hinder construction such as excavation after ground improvement.
本発明の目的は、液状化が予想される砂質地盤を改良して液状化を防止する地盤改良工法の一つであるジェットグラウト工法において、地盤の細粒分に影響されることなく、必要以上の強度ではない低強度でかつ広範囲の改良が可能なジェットグラウト工法を提供することである。 The purpose of the present invention is to improve the sandy ground where liquefaction is expected and to prevent liquefaction. The present invention is to provide a jet grouting method which is not low in strength but can be improved over a wide range.
上述した課題を解決するために、本発明は以下の構成を有する。 In order to solve the above-described problems, the present invention has the following configuration.
本発明の第１の態様は、砂質地盤の液状化対策用ジェットグラウト工法であって、主剤である微粒子スラグと、促進剤である微粒子消石灰と、分散剤であるポリカルボン酸塩系高分子と、残部の水とからなる地盤改良材を用いることを特徴とする。 A first aspect of the present invention is a jet grouting method for liquefaction countermeasures for sandy ground, in which fine particle slag as a main agent, fine particle slaked lime as an accelerator, and polycarboxylate polymer as a dispersant And the ground improvement material which consists of remaining water is used, It is characterized by the above-mentioned.
上記の態様において、前記地盤改良材１ｍ３当たりの配合として、主剤である前記微粒子スラグが６０〜３８０ｋｇ、促進剤である前記微粒子消石灰が７．５〜１００ｋｇ、分散剤である前記ポリカルボン酸塩系高分子が５〜３０ｋｇ、水が７９０〜９７０ｋｇであることを特徴とする。 In the above aspect, the composition per 1 m 3 of the ground improvement material is 60 to 380 kg of the fine particle slag as a main agent, 7.5 to 100 kg of the fine particle slaked lime as an accelerator, and the polycarboxylate salt as a dispersant. The system polymer is 5 to 30 kg, and water is 790 to 970 kg.
上記の態様において、前記地盤改良材の砂ゲル強度が、相対密度６０％の場合かつ材令２８日において、２．５Ｎ／ｍｍ２以下であることを特徴とする。 Said aspect WHEREIN: The sand gel intensity | strength of the said ground improvement material is 2.5 N / mm < 2 > or less in the case of a relative density of 60% and material age 28 days, It is characterized by the above-mentioned.
上記の態様において、主剤である前記微粒子スラグのブレーン比表面積が４０００ｃｍ２／ｇ以上であることを特徴とする。 Said aspect WHEREIN: The brane specific surface area of the said fine particle slag which is a main ingredient is 4000 cm < 2 > / g or more, It is characterized by the above-mentioned.
上記の態様において、促進剤である前記微粒子消石灰の平均粒子径が８μｍ以下であることを特徴とする。 Said aspect WHEREIN: The average particle diameter of the said fine particle slaked lime which is an accelerator is 8 micrometers or less, It is characterized by the above-mentioned.
上記の態様において、前記地盤改良材の硬化時間が８時間以上であることを特徴とする。 Said aspect WHEREIN: The hardening time of the said ground improvement material is 8 hours or more, It is characterized by the above-mentioned.
本発明の第２の態様は、砂質地盤の液状化対策用ジェットグラウト工法であって、主剤である微粒子スラグと、分散剤であるポリカルボン酸塩系高分子と水とからなる第１液と、促進剤である微粒子消石灰と水とからなる第２液を１つの造成管内に設けられた個別の送管によりそれぞれ圧送し、前記造成管の先端に設けられた個別の噴射装置によりそれぞれ噴射し、前記第１液と前記第２液を地盤中で混合させることを特徴とする。 The second aspect of the present invention is a jet grouting method for liquefaction countermeasures for sandy ground, which is a first liquid comprising fine particle slag as a main agent, a polycarboxylate polymer as a dispersant, and water. And a second liquid composed of fine slaked lime and water, which are accelerators, are respectively pumped by individual pipes provided in one forming pipe, and are respectively injected by individual injection devices provided at the tip of the forming pipe. The first liquid and the second liquid are mixed in the ground.
本発明の液状化対策用ジェットグラウト工法によれば、砂質地盤において、地盤の細粒分に影響されることなく、必要以上の強度ではない低強度でかつ広範囲の地盤改良を行うことができる。 According to the jet grouting method for liquefaction countermeasures of the present invention, in a sandy ground, it is possible to make a wide range of ground improvement at a low strength that is not unnecessarily strong, without being affected by fine particles of the ground. .
本発明の液状化対策用ジェットグラウト工法によれば、微粒子スラグ、微粒子消石灰、ポリカルボン酸塩系高分子の配合により、改良体強度及び硬化時間を調整できるため、対象地盤に適した材料を供給することができる。 According to the jet grouting method for countermeasures against liquefaction of the present invention, the strength of the improved body and the curing time can be adjusted by blending fine particle slag, fine particle slaked lime, and polycarboxylate-based polymer. can do.
さらに、従来技術に比べ排泥の発生量が低減されるため、環境負荷や処分コストを低減することができる。 Furthermore, since the amount of generated mud is reduced as compared with the prior art, it is possible to reduce environmental load and disposal cost.
以下、図面を参考にしつつ、本発明による液状化対策用ジェットグラウト工法について詳細に説明する。 Hereinafter, the liquefaction countermeasure jet grouting method according to the present invention will be described in detail with reference to the drawings.
図１は、液状化対策用ジェットグラウト工法の一般的な施工手順の例を模式的に表した図である。 FIG. 1 is a diagram schematically showing an example of a general construction procedure of a jet grouting method for countermeasures against liquefaction.
液状状化対策用ジェットグラウト工法では、まず（ａ）の設置工程において、対象の砂質地盤の地上に地盤改良装置１０を設置する。次に（ｂ）の削孔工程において、目的の深度まで造成管１１により削孔し、造成管１１を建て込む。造成管１１の中には、地盤改良材１２を圧送するための送管が設けられ、送管は造成管１１の先端に設けられた噴射孔に連通している。（ｃ）の造成工程において、造成管１１を回転させつつ引き上げると同時に、造船管１１の先端の噴射孔から地盤改良材１２を高圧噴射する。地盤改良材１２は砂質地盤中に浸透していく。所定の深度において噴射を停止し、造成管１１を引き上げる。地盤改良材１２と砂質地盤が混合され固化すると（ｄ）に示すように円柱状の地盤改良体１３が造成される。
In the liquefaction countermeasure jet grouting method, first, in the installation step (a), the
以下に説明する本発明の地盤改良材１２を用いることにより、必要以上の強度ではない低強度でかつ従来よりも広範囲の地盤改良体１３が得られる。
By using the
本発明の第１の態様の液状化対策用ジェットグラウト工法に用いられる地盤改良材は、主剤である微粒子スラグと、促進剤である微粒子消石灰と、分散剤であるポリカルボン酸塩系高分子とを成分として含み、さらに水と混合されたスラリー状のものである。 The ground improvement material used in the jet grouting method for liquefaction countermeasures according to the first aspect of the present invention includes fine particle slag as a main agent, fine particle slaked lime as an accelerator, and a polycarboxylate polymer as a dispersant. In the form of a slurry mixed with water.
地盤改良材１ｍ３当たりの配合として、主剤である微粒子スラグが６０〜３８０ｋｇであることが好ましい。微粒子スラグが６０ｋｇ以下では材令２８日における地盤改良体の強度発現が起きず、３８０ｋｇ以上では粘度が大きくなりすぎるため砂質地盤への浸透が阻害される。 As a composition per 1 m 3 of the ground improvement material, it is preferable that the fine particle slag as the main agent is 60 to 380 kg. If the fine particle slag is 60 kg or less, the strength improvement of the ground improvement body on the 28th day of the material age does not occur, and if it is 380 kg or more, the viscosity becomes too large and the penetration into the sandy ground is inhibited.
地盤改良材１ｍ３当たりの配合として、促進剤である微粒子消石灰が７．５〜１００ｋｇであることが好ましい。微粒子消石灰が７．５ｋｇ以下では微粒子スラグの強度発現に寄与せず、１００ｋｇ以上ではやはり砂質地盤への浸透が阻害される。 As blending per 1 m 3 of ground improvement material, it is preferable that fine slaked lime which is an accelerator is 7.5 to 100 kg. When the fine slaked lime is 7.5 kg or less, it does not contribute to the development of the strength of the fine particle slag, and when it is 100 kg or more, the penetration into the sandy ground is also inhibited.
地盤改良材１ｍ３当たりの配合として、分散剤であるポリカルボン酸塩系高分子が５〜３０ｋｇであることが好ましい。ポリカルボン酸塩系高分子が５ｋｇ以下では微粒子スラグ及び微粒子消石灰に対する水の分散効果が小さく、３０ｋｇ以上入れても分散効果は変わらない。 As a composition per 1 m 3 of the ground improvement material, it is preferable that 5 to 30 kg of the polycarboxylate polymer as a dispersant is used. When the amount of the polycarboxylate polymer is 5 kg or less, the effect of dispersing water on the fine particle slag and fine particle slaked lime is small, and even if 30 kg or more is added, the dispersion effect does not change.
地盤改良材１ｍ３当たりの配合として、水が７９０〜９７０ｋｇであることが好ましい。水は、地盤改良材１ｍ３当たり、上述した主剤である微粒子スラグ、促進剤である微粒子消石灰及び分散剤であるポリカルボン酸塩系高分子の３成分を適切に配合し、その残部として加える。 As a composition per 1 m 3 of the ground improvement material, water is preferably 790 to 970 kg. For 1 m 3 of the ground improvement material, water is appropriately blended with the above-described three components of fine particle slag as the main agent, fine particle slaked lime as an accelerator, and polycarboxylate polymer as a dispersant, and is added as the remainder.
本発明に用いる主剤である微粒子スラグの種類は特に限定しないが、高炉における製鋼により排出される融解スラグとして一般的に知られているものを使用できる。 Although the kind of fine particle slag which is a main ingredient used for this invention is not specifically limited, What is generally known as molten slag discharged | emitted by steelmaking in a blast furnace can be used.
微粒子スラグは、セメントと異なり粘度が低いことから、砂質地盤への浸透性に優れる。高圧噴射による撹拌範囲よりさらに広く地盤改良材を浸透させるためには、より微粒子の微粒子スラグを用いることが好ましい。よって微粒子の大きさの目安として、好適にはブレーン比表面積が４０００ｃｍ２／ｇ以上であり、さらに好適には８０００ｃｍ２／ｇ以上である。ブレーン比表面積が４０００ｃｍ２／ｇより小さいと砂質地盤への浸透が低下する。８０００ｃｍ２／ｇ以上のものを用いると、細粒分含有率（Ｆｃ）が２０％以上の地盤へも浸透が可能となる。ブレーン比表面積はブレーン空気透過法により求められる。 Fine particle slag has a low viscosity unlike cement, and therefore has excellent permeability to sandy ground. In order to infiltrate the ground improvement material more widely than the stirring range by high-pressure injection, it is preferable to use finer particle slag. Therefore, as a measure of the size of the fine particles, the Blaine specific surface area is preferably 4000 cm 2 / g or more, and more preferably 8000 cm 2 / g or more. When the Blaine specific surface area is smaller than 4000 cm 2 / g, the penetration into the sandy ground is lowered. When a material having a particle size of 8000 cm 2 / g or more is used, it can penetrate into the ground having a fine particle content (Fc) of 20% or more. The specific surface area of the brane is determined by the brane air permeation method.
微粒子スラグを、高圧噴射による撹拌範囲よりさらに広い範囲に浸透させることにより、セメントを用いた従来の場合よりも大きな改良体が造成され、改良範囲が拡大する。さらに、セメントを用いた従来の地盤改良材よりも、地盤中により多く浸透するため、排泥の発生量が低減する。 By allowing the fine particle slag to permeate a wider range than the stirring range by high-pressure injection, an improved body larger than the conventional case using cement is formed, and the improved range is expanded. Furthermore, since it penetrates more into the ground than conventional ground improvement materials using cement, the amount of generated mud is reduced.
本発明に用いる微粒子消石灰についても、高圧噴射による撹拌範囲よりさらに広く地盤改良材を浸透させるために、より微細なものが好ましい。篩い分級による平均粒子径８μｍ以下であることが好ましく、さらに好適には４μｍ以下である。平均粒子径が８μｍより大きいと砂質地盤への浸透が低下する。平均粒子径が４μｍ以下のものを用いると、細粒分含有率（Ｆｃ）が２０％以上の地盤への浸透が可能となる。 The fine slaked lime used in the present invention is also preferably finer in order to allow the ground improvement material to penetrate more widely than the stirring range by high-pressure injection. The average particle size by sieving is preferably 8 μm or less, and more preferably 4 μm or less. When the average particle size is larger than 8 μm, the penetration into the sandy ground is lowered. When a particle having an average particle diameter of 4 μm or less is used, it is possible to penetrate into the ground having a fine particle content (Fc) of 20% or more.
本発明に用いる分散剤であるポリカルボン酸塩系高分子は、高性能ＡＥ減水剤として知られている公知のポリカルボン酸塩系高分子を使用することができる。例えばポリカルボン酸ナトリウム、ポリカルボン酸アンモニウム等がある。ポリカルボン酸塩系高分子は、微粒子スラグ及び微粒子消石灰の分散性を向上させるだけでなく、微粒子スラグの硬化を阻害しない点で好適である。セメントの分散剤に一般的に用いられるオキシカルボン酸塩やリグニンスルホン酸塩系は、微粒子スラグの硬化を阻害するため好ましくない。 A known polycarboxylate polymer known as a high-performance AE water reducing agent can be used as the polycarboxylate polymer that is a dispersant used in the present invention. Examples include sodium polycarboxylate and ammonium polycarboxylate. The polycarboxylate-based polymer is suitable not only for improving the dispersibility of the fine particle slag and fine particle slaked lime but also for preventing the hardening of the fine particle slag. Oxycarboxylates and lignin sulfonates generally used for cement dispersants are not preferred because they inhibit the hardening of fine particle slag.
本発明の第２の態様の液状化対策用ジェットグラウト工法では、主剤である微粒子スラグと、分散剤と、水とからなる第１液と、促進剤である微粒子消石灰と、水とからなる第２液を用いる。例えば図１に示した造成管１１内に第１液と第２液を個別に圧送するための２本の送管が設けられており、各送管は個別に設けられた２つの噴射孔にそれぞれ連通している。第１液と第２液は、造成管１１の先端の２つの噴射孔から個別に噴射され、地盤中で混合されることになる。 In the jet grouting method for countermeasure against liquefaction according to the second aspect of the present invention, a first liquid comprising fine particle slag as a main agent, a dispersant, water, fine particle slaked lime as an accelerator, and water. Two liquids are used. For example, two pipes for individually feeding the first liquid and the second liquid are provided in the forming pipe 11 shown in FIG. 1, and each pipe is provided in two jet holes provided individually. Each communicates. The first liquid and the second liquid are individually injected from the two injection holes at the tip of the forming tube 11 and mixed in the ground.
本発明の地盤改良材は、これを用いて固化した砂ゲルのゲル強度が、相対密度６０％の場合かつ材令２８日において、２．５Ｎ/ｍｍ２以下であることが好ましい。ここでの砂ゲルは、本発明の地盤改良材と６号珪砂を混合した混合物である。 In the ground improvement material of the present invention, it is preferable that the gel strength of the sand gel solidified using the ground improvement material is 2.5 N / mm 2 or less when the relative density is 60% and the material age is 28 days. The sand gel here is a mixture of the ground improvement material of the present invention and No. 6 silica sand.
相対密度は以下の式で求められる。
相対密度＝［最大間隙比−間隙比］／［最大間隙比−最小間隙比］
間隙比は、以下の式で求められる。
間隙比＝［気相＋液相の部分の体積］／［固相部分の体積］
なお最大間隙比及び最小間隙比は公知の試験法により求められる。
The relative density is obtained by the following formula.
Relative density = [maximum gap ratio-gap ratio] / [maximum gap ratio-minimum gap ratio]
The gap ratio is obtained by the following formula.
Pore ratio = [gas phase + volume of liquid phase portion] / [volume of solid phase portion]
The maximum gap ratio and the minimum gap ratio are obtained by a known test method.
本発明の地盤改良材の硬化時間は、上述した成分及びその成分量の範囲内で作製した場合、８時間以上である。 The curing time of the ground improvement material of this invention is 8 hours or more, when it produces within the range of the component mentioned above and its component amount.
以下、具体的な実施例についての試験結果を示す。
（１）試験１
＜試験方法＞
本発明に用いる地盤改良材とセメント系の地盤改良材の地盤への浸透性を比較するために、表１に示す実施例１、２及び比較例１の地盤改良材を作製した。また、内径３ｃｍの塩化ビニル管に５号珪砂を間隙率４０％となるように詰め、深さ３０ｃｍの仮想地盤を作製した。実施例１、２及び比較例１の地盤改良材を仮想地盤の上部からそれぞれ自然浸透させ、３０ｃｍの仮想地盤を通過する時間を比較した。
The test results for specific examples are shown below.
(1) Test 1
<Test method>
In order to compare the permeability of the ground improvement material used in the present invention and the cement-based ground improvement material into the ground, the ground improvement materials of Examples 1 and 2 and Comparative Example 1 shown in Table 1 were prepared. In addition, No. 5 silica sand was packed in a vinyl chloride tube having an inner diameter of 3 cm so as to have a porosity of 40%, thereby producing a virtual ground having a depth of 30 cm. The ground improvement materials of Examples 1 and 2 and Comparative Example 1 were naturally permeated from the upper part of the virtual ground, and the time required to pass through the virtual ground of 30 cm was compared.
実施例１、２に用いた微粒子スラグ及び微粒子消石灰の特性は以下のとおりである。
微粒子スラグＡ：ブレーン比表面積８０００ｃｍ２／ｇ
微粒子スラグＢ：ブレーン比表面積４０００ｃｍ２／ｇ
微粒子消石灰Ａ：平均粒子径４μｍ
微粒子消石灰Ｂ：平均粒子径８μｍ
The characteristics of the fine particle slag and fine particle slaked lime used in Examples 1 and 2 are as follows.
Fine particle slag A: Blaine specific surface area 8000 cm 2 / g
Fine particle slag B: Blaine specific surface area 4000 cm 2 / g
Fine slaked lime A: average particle size 4 μm
Fine slaked lime B: average particle size 8 μm
なお、実施例１、２を地盤改良材１ｍ３当たりに換算すると以下の通りとなる。
・主剤３７５ｋｇ、促進剤３５ｋｇ、分散剤１０ｋｇ、水８５０ｋｇ
比較例１の分散剤はナフタレンスルフォン酸系界面活性剤である。
Incidentally, the following as the first and second embodiments in terms of the soil improvement material 1 m 3 per.
・ Main agent 375 kg, accelerator 35 kg,
The dispersant of Comparative Example 1 is a naphthalene sulfonic acid surfactant.
＜試験結果＞
実施例１の地盤改良材は、３０ｃｍの仮想地盤を２分３０秒で通過した。
実施例２の地盤改良材は、３０ｃｍの仮想地盤を５分間で通過した。
実施例３の地盤改良材は、３ｃｍ程度で浸透が止まった。
微粒子スラグを主剤とした地盤改良材はセメントを主剤とした地盤改良材に比較して地盤への浸透性が良好であった。実施例２に比べてより微細な微粒子スラグ及び微粒子消石灰を使用した実施例１の場合にさらに浸透性が良好であった。
<Test results>
The ground improvement material of Example 1 passed 30 cm virtual ground in 2 minutes 30 seconds.
The ground improvement material of Example 2 passed 30 cm of virtual ground in 5 minutes.
The ground improvement material of Example 3 stopped permeating at about 3 cm.
The ground improvement material mainly composed of fine particle slag had better permeability to the ground than the ground improvement material mainly composed of cement. Compared with Example 2, in the case of Example 1 using finer fine particle slag and fine particle slaked lime, the permeability was even better.
（２）試験２
＜試験方法＞
微粒子スラグの量や分散剤の種類が地盤改良材の硬化に与える影響について比較するために、表２に示す実施例１、３及び比較例２の地盤改良材を作製した。直径５ｃｍ×高さ１０ｃｍのモールドに相対密度が６０％になるように、それぞれの地盤改良材及び６号珪砂を用いて供試体を作製し、２８日後の一軸圧縮強度を測定した。
(2) Test 2
<Test method>
In order to compare the effects of the amount of fine particle slag and the type of dispersant on the hardening of the ground improvement material, the ground improvement materials of Examples 1 and 3 and Comparative Example 2 shown in Table 2 were prepared. A specimen was prepared using each ground improvement material and No. 6 silica sand so that the relative density was 60% in a mold having a diameter of 5 cm and a height of 10 cm, and the uniaxial compressive strength after 28 days was measured.
なお、実施例３を地盤改良材１ｍ３当たりに換算すると以下の通りとなる。
・主剤１８８ｋｇ、促進剤３５ｋｇ、分散剤１０ｋｇ、水８５０ｋｇ
比較例２のグルコン酸ナトリウムは３３％溶液である。
Incidentally, the following as the third embodiment in terms of the soil improvement material 1 m 3 per.
・ Main agent 188kg, accelerator 35kg, dispersant 10kg, water 850kg
The sodium gluconate of Comparative Example 2 is a 33% solution.
＜試験結果＞
実施例１の地盤改良材では、一軸圧縮強度が２．００Ｎ／ｍｍ２であった。
実施例３の地盤改良材では、一軸圧縮強度が１．１０Ｎ／ｍｍ２であった。
比較例２の地盤改良材では、固化しなかった。
<Test results>
The soil improvement material of Example 1, the uniaxial compressive strength was 2.00 N / mm 2.
In the ground improvement material of Example 3, the uniaxial compressive strength was 1.10 N / mm 2 .
The ground improvement material of Comparative Example 2 did not solidify.
オキシカルボン酸塩であるグルコン酸ナトリウムは微粒子スラグを主剤とする地盤改良材の硬化を阻害する。また、微粒子スラグの含有率が少ないほど低強度となる。 Sodium gluconate, which is an oxycarboxylate, inhibits the hardening of the ground improvement material mainly composed of fine particle slag. Moreover, it becomes low intensity | strength, so that there is little content rate of fine particle slag.
（３）試験３
実際の地盤を対象に以下の条件で試験を行った。
・地盤改良材：実施例１、比較例１
・対象地盤 ：砂質土
・噴射圧力 ：４０ＭＰａ
・噴射量 ：１００Ｌ／分
・造成時間 ：４分／ｍ
・噴射方法 ：２方向噴射
(3) Test 3
The test was performed on the actual ground under the following conditions.
・ Ground improvement material: Example 1, Comparative Example 1
-Target ground: sandy soil-Injection pressure: 40 MPa
・ Injection amount: 100L / min ・ Formation time: 4min / m
・ Injection method: Two-way injection
＜試験結果＞
造成された地盤改良体の直径及び強度の測定結果を表３に示す。
<Test results>
Table 3 shows the measurement results of the diameter and strength of the ground improvement body.
微粒子スラグを使用した実施例１の地盤改良体は、セメント系を使用した比較例１のものと比較すると１．５倍の大きさが得られた。これは、高圧噴射による地盤切削による撹拌範囲よりさらに外側に微粒子スラグ系材料の浸透範囲が加わったためと考えられる。また実施例１の地盤改良体強度は、比較例１のものより低く、必要以上に高強度となっておらず、液状化対策としては十分な強度を有している。 The ground improvement body of Example 1 using fine particle slag was 1.5 times as large as that of Comparative Example 1 using cement. This is considered to be because the penetration range of the particulate slag-based material was added to the outside of the stirring range by ground cutting by high pressure injection. Moreover, the ground improvement body intensity | strength of Example 1 is lower than the thing of the comparative example 1, is not high intensity | strength more than necessary, and has sufficient intensity | strength as a countermeasure against liquefaction.
１０ 地盤改良機
１１ 造成管
１２ 地盤改良材
１３ 改良体
10 Ground improvement machine 11
Claims (7)
液状化対策用ジェットグラウト工法。 A jet grouting method for liquefaction of sandy ground, consisting of fine slag as the main agent, fine slaked lime as an accelerator, polycarboxylate polymer as a dispersant, and the balance water A jet grouting method for liquefaction countermeasures, characterized by using an improved material.
請求項１に記載の液状化対策用ジェットグラウト工法。 As the composition per 1 m 3 of the ground improvement material, 60 to 380 kg of the fine particle slag as a main agent, 7.5 to 100 kg of the fine particle slaked lime as an accelerator, and 5 of the polycarboxylate polymer as a dispersing agent. The jet grouting method for liquefaction countermeasures according to claim 1, wherein -30 kg and water are 790 to 970 kg.
請求項１又は２に記載の液状化対策用ジェットグラウト工法。 The jet grouting for liquefaction countermeasures according to claim 1 or 2, wherein the sand gel strength of the ground improvement material is 2.5 N / mm 2 or less at a relative density of 60% and a material age of 28 days. Construction method.
請求項１〜３のいずれかに記載の液状化対策用ジェットグラウト工法。 The jet grouting method for liquefaction countermeasures according to any one of claims 1 to 3, wherein the fine particle slag as a main agent has a brain specific surface area of 4000 cm 2 / g or more.
請求項１〜４のいずれかに記載の液状化対策用ジェットグラウト工法。 The jet grouting method for liquefaction countermeasures according to any one of claims 1 to 4, wherein the fine particle slaked lime as an accelerator has an average particle size of 8 µm or less.
請求項１〜５のいずれかに記載の液状化対策用ジェットグラウト工法。 The grouting countermeasure jet grouting method according to any one of claims 1 to 5, wherein a curing time of the ground improvement material is 8 hours or more.
液状化対策用ジェットグラウト工法。 A jet grouting method for liquefaction countermeasures for sandy ground, comprising a fine particle slag as a main agent, a first liquid composed of a polycarboxylate-based polymer and water as a dispersant, and fine particle slaked lime as an accelerator. A second liquid composed of water is pumped by an individual pipe provided in one forming pipe, and is jetted by an individual jetting device provided at a tip of the forming pipe. A jet grouting method for liquefaction countermeasures, characterized by mixing two liquids in the ground.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11228960A (en) * | 1998-02-10 | 1999-08-24 | Mitsui Chem Inc | Suspended grout composition |
| JP2003278144A (en) * | 2002-03-22 | 2003-10-02 | Sankoo Chemical Kk | Impregnation method |
| JP2005097413A (en) * | 2003-09-25 | 2005-04-14 | Mitsui Kagaku Sanshi Kk | Method for preparing suspension type soil stabilizer |
| JP2010150752A (en) * | 2008-12-24 | 2010-07-08 | Fudo Tetra Corp | Grouting method for suspension type grouting agent |
| JP2014231567A (en) * | 2013-05-29 | 2014-12-11 | 有限会社シモダ技術研究所 | Permeable fine particle grout material |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11228960A (en) * | 1998-02-10 | 1999-08-24 | Mitsui Chem Inc | Suspended grout composition |
| JP2003278144A (en) * | 2002-03-22 | 2003-10-02 | Sankoo Chemical Kk | Impregnation method |
| JP2005097413A (en) * | 2003-09-25 | 2005-04-14 | Mitsui Kagaku Sanshi Kk | Method for preparing suspension type soil stabilizer |
| JP2010150752A (en) * | 2008-12-24 | 2010-07-08 | Fudo Tetra Corp | Grouting method for suspension type grouting agent |
| JP2014231567A (en) * | 2013-05-29 | 2014-12-11 | 有限会社シモダ技術研究所 | Permeable fine particle grout material |
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