JP2019178597A - Method for predicting strength development property of foundation improved soil - Google Patents
Method for predicting strength development property of foundation improved soil Download PDFInfo
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- 239000002689 soil Substances 0.000 title claims abstract description 42
- 238000011161 development Methods 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 59
- 239000004568 cement Substances 0.000 claims abstract description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 39
- 239000002002 slurry Substances 0.000 claims abstract description 29
- 238000007711 solidification Methods 0.000 claims abstract description 22
- 230000008023 solidification Effects 0.000 claims abstract description 22
- 238000006703 hydration reaction Methods 0.000 claims abstract description 9
- 239000002253 acid Substances 0.000 claims description 16
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims description 14
- 229920005610 lignin Polymers 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 6
- 229920000877 Melamine resin Polymers 0.000 claims description 5
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims description 5
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 claims description 4
- 229920005862 polyol Polymers 0.000 claims description 4
- 150000003077 polyols Chemical class 0.000 claims description 4
- 150000001413 amino acids Chemical class 0.000 claims description 3
- 230000002349 favourable effect Effects 0.000 claims description 3
- 229920002401 polyacrylamide Polymers 0.000 claims description 3
- 229920003169 water-soluble polymer Polymers 0.000 claims description 3
- 230000001186 cumulative effect Effects 0.000 abstract description 8
- 230000002123 temporal effect Effects 0.000 abstract 1
- 239000003638 chemical reducing agent Substances 0.000 description 29
- 239000002562 thickening agent Substances 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 4
- 239000004480 active ingredient Substances 0.000 description 3
- 230000020169 heat generation Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- ATVJXMYDOSMEPO-UHFFFAOYSA-N 3-prop-2-enoxyprop-1-ene Chemical class C=CCOCC=C ATVJXMYDOSMEPO-UHFFFAOYSA-N 0.000 description 2
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- 239000001913 cellulose Chemical class 0.000 description 2
- 229920002678 cellulose Chemical class 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- -1 polyoxyethylene Polymers 0.000 description 2
- 239000013077 target material Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 229920001222 biopolymer Polymers 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000012669 compression test Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 229920000172 poly(styrenesulfonic acid) Polymers 0.000 description 1
- 229940005642 polystyrene sulfonic acid Drugs 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910021487 silica fume Inorganic materials 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- IIACRCGMVDHOTQ-UHFFFAOYSA-N sulfamic acid Chemical compound NS(O)(=O)=O IIACRCGMVDHOTQ-UHFFFAOYSA-N 0.000 description 1
Abstract
Description
本発明は、地盤改良土の強度発現性の予測方法に関する。 The present invention relates to a method for predicting strength development of ground improved soil.
減水剤等のセメント混和剤の過剰な添加によって、凝結遅延が起こり、硬化後の目標強度（初期強度）が得られないという問題が生じうることが、知られている（例えば、特許文献１の段落０００３参照）。 It is known that excessive addition of a cement admixture such as a water reducing agent may cause a setting delay and cause a problem that a target strength (initial strength) after curing cannot be obtained (for example, Patent Document 1). (See paragraph 0003).
セメント系固化材を用いて軟弱地盤を固化処理して改良するなどの地盤改良工事において、被処理土の強度発現性の調整等を目的として、セメント混和剤（例えば、遅延剤、ＡＥ減水剤等）を用いることがある。
しかし、セメント混和剤の主成分の種類によっては、セメント混和剤を過剰な量で用いると、例えば、材齢２８日の被処理土の一軸圧縮強さが、目標とする値を大きく下回るなどの、強度発現性の問題が生じることがある。
この問題に対処するためには、例えば、被処理土のサンプル、及び、使用予定量のセメント混和剤を用いて、実際に、被処理土の固化処理物を作製し、この固化処理物について、例えば、材齢２８日の被処理土の一軸圧縮強さを測定すれば、強度発現性の良否を確認することができる。
しかし、この場合、強度発現性の良否の確認のために、２８日間を要することになる。
本発明の目的は、セメント系固化材、セメント混和剤、及び水を含む固化材スラリーを用いて、地盤改良工事を行う場合において、地盤改良土（固化処理後の被処理土）の例えば材齢２８日の強度発現性を、簡易にかつ短時間（例えば、３日間）で予測することができる方法を提供することである。
Cement admixtures (for example, retarders, AE water reducing agents, etc.) for the purpose of adjusting the strength of soil to be treated in ground improvement works such as solidifying and improving soft ground using cement-based solidification materials ) May be used.
However, depending on the type of the main component of the cement admixture, if the cement admixture is used in an excessive amount, for example, the uniaxial compressive strength of the soil to be treated at the age of 28 is significantly lower than the target value. , Strength development problems may occur.
In order to deal with this problem, for example, using a sample of the soil to be treated and a cement admixture of the amount to be used, a solidified product of the soil to be treated is actually produced. For example, if the uniaxial compressive strength of the soil to be treated at the age of 28 days is measured, the quality of the strength can be confirmed.
However, in this case, 28 days are required to confirm whether the strength developability is good.
The object of the present invention is, for example, the age of the ground improvement soil (the soil to be treated after the solidification treatment) when the ground improvement work is performed using a solidification slurry containing a cement-based solidification material, a cement admixture, and water. It is to provide a method capable of predicting the strength development property of 28 days easily and in a short time (for example, 3 days).
本発明者は、上記課題を解決するために鋭意検討した結果、セメント系固化材、セメント混和剤、及び水を含む固化材スラリーについて、水和反応熱の経時変化を検出可能な熱量計を用いて、所定の材齢における積算発熱量を算出した後、該積算発熱量の値に基いて、上記所定の材齢よりも後の材齢における、固化材スラリーを用いた固化処理後の地盤改良土の強度発現性を予測するという方法によれば、前記の目的を達成しうることを見出し、本発明を完成した。 As a result of intensive studies to solve the above-mentioned problems, the present inventor used a calorimeter capable of detecting a change in heat of hydration reaction over time for a solidified material slurry containing a cement-based solidified material, a cement admixture, and water. Then, after calculating the integrated calorific value at a predetermined age, based on the value of the accumulated calorific value, the ground improvement after the solidification treatment using the solidified material slurry at an age later than the predetermined age It has been found that the above object can be achieved by a method of predicting the strength development of soil, and the present invention has been completed.
すなわち、本発明は、以下の［１］〜［５］を提供するものである。
［１］ セメント系固化材、セメント混和剤、及び水を含む固化材スラリーについて、水和反応熱の経時変化を検出可能な熱量計を用いて、所定の材齢における積算発熱量を算出する積算発熱量算出工程、及び、上記積算発熱量の値に基いて、上記所定の材齢よりも後の材齢における、上記固化材スラリーを用いた固化処理後の地盤改良土の強度発現性を予測する強度発現性予測工程、を含むことを特徴とする地盤改良土の強度発現性の予測方法。
［２］ 上記積算発熱量算出工程における上記所定の材齢が、１〜５日であり、かつ、上記強度発現性予測工程における上記所定の材齢よりも後の材齢が、７日以上である、前記［１］に記載の地盤改良土の強度発現性の予測方法。
［３］ 上記セメント混和剤を含まない以外は上記固化材スラリーと同じ材料組成を有する対照用スラリーについて、上記積算発熱量算出工程と同様にして、上記積算発熱量を算出し、得られた値を基準値として定める基準値算出工程を含み、かつ、上記強度発現性予測工程において、上記固化材スラリーについて得られた上記積算発熱量（Ａ）と、上記対照用スラリーについて得られた上記基準値（Ｂ）との比（（Ａ）／（Ｂ）×１００（％））が、予め定めた値以上である場合に、上記強度発現性が良好であると予測する、前記［１］又は［２］に記載の地盤改良土の強度発現性の予測方法。
［４］ 上記比についての上記予め定めた値が、２０〜１００％の範囲内で定めた値である、前記［１］〜［３］のいずれかに記載の地盤改良土の強度発現性の予測方法。
［５］ 上記セメント混和剤が、オキシカルボン酸系の混和剤、ポリオキシカルボン酸系の混和剤、リグニンスルホン酸系の混和剤、ナフタレンスルホン酸系の混和剤、メラミンスルホン酸系の混和剤、アミノ酸系の混和剤、ポリオール系の混和剤、水溶性高分子系の混和剤、及び、ポリアクリルアミド系の混和剤からなる群より選ばれる一種以上である、前記［１］〜［４］のいずれかに記載の地盤改良土の強度発現性の予測方法。
That is, the present invention provides the following [1] to [5].
[1] Integration for calculating an integrated calorific value at a given age using a calorimeter capable of detecting a change in heat of hydration reaction over time for a solidified slurry containing cement-based solidified material, cement admixture, and water Based on the calorific value calculation step and the value of the integrated calorific value, the strength development property of the ground improved soil after the solidification treatment using the solidification material slurry at the age after the predetermined age is predicted. A method for predicting the strength development of the ground improved soil, comprising the step of predicting the strength development.
[2] The predetermined material age in the integrated calorific value calculation step is 1 to 5 days, and the material age after the predetermined material age in the strength development predicting step is 7 days or more. The method for predicting strength development of the ground improved soil according to [1].
[3] For the control slurry having the same material composition as the solidifying material slurry except that the cement admixture is not included, the integrated calorific value is calculated in the same manner as the integrated calorific value calculating step, and the obtained value And the reference value obtained for the control slurry, and the integrated calorific value (A) obtained for the solidified material slurry in the strength development predicting step. When the ratio ((A) / (B) × 100 (%)) with (B) is equal to or greater than a predetermined value, the above-described strength development is predicted to be favorable, [1] or [ [2] The method for predicting strength development of ground improved soil according to [2].
[4] The strength development property of the ground improved soil according to any one of [1] to [3], wherein the predetermined value for the ratio is a value determined within a range of 20 to 100%. Prediction method.
[5] The cement admixture is an oxycarboxylic acid based admixture, a polyoxycarboxylic acid based admixture, a lignin sulfonic acid based admixture, a naphthalene sulfonic acid based admixture, a melamine sulfonic acid based admixture, Any one of [1] to [4], which is at least one selected from the group consisting of an amino acid-based admixture, a polyol-based admixture, a water-soluble polymer-based admixture, and a polyacrylamide-based admixture. A method for predicting the strength development of ground improved soil according to crab
本発明によれば、セメント系固化材、セメント混和剤、及び水を含む固化材スラリーを用いて、地盤改良工事を行う場合において、地盤改良土（固化処理後の被処理土）の例えば材齢２８日の強度発現性を、簡易にかつ短時間（例えば、３日間）で予測することができる。 According to the present invention, when performing ground improvement work using a solidified material slurry containing a cement-based solidifying material, a cement admixture, and water, for example, the age of the ground improved soil (treated soil after solidification treatment) It is possible to predict the 28-day strength development easily and in a short time (for example, 3 days).
本発明の地盤改良土の強度発現性の予測方法は、（ａ）セメント系固化材（例えば、セメント及び他の有効成分を含むもの）、及び、セメント混和剤（例えば、凝結遅延剤、高性能ＡＥ減水剤等）、及び水を含む固化材スラリーについて、水和反応熱の経時変化を検出可能な熱量計を用いて、所定の材齢（例えば、３日）における積算発熱量を算出する積算発熱量算出工程、及び、（ｂ）上記積算発熱量の値に基いて、上記所定の材齢よりも後の材齢（例えば、７〜２８日）における、上記固化材スラリーを用いた固化処理後の地盤改良土の強度発現性を予測する強度発現性予測工程、を含むものである。
以下、工程毎に詳しく説明する。
The method for predicting the strength development of the ground improved soil of the present invention includes (a) a cement-based solidifying material (for example, containing cement and other active ingredients) and a cement admixture (for example, a setting retarder, a high performance AE water-reducing agent, etc.), and an integrated calorimeter that can detect a change with time in the heat of hydration reaction, and an integrated calorimeter that calculates the accumulated calorific value at a given material age (for example, 3 days) A calorific value calculation step, and (b) a solidification treatment using the solidified material slurry at an age later than the predetermined age (for example, 7 to 28 days) based on the value of the accumulated calorific value. A strength development predicting step for predicting the strength development of the ground improved soil later.
Hereinafter, each process will be described in detail.
［工程（ａ）：積算発熱量算出工程］
工程（ａ）は、セメント系固化材、及び、セメント混和剤、及び水を含む固化材スラリーについて、水和反応熱の経時変化を検出可能な熱量計を用いて、所定の材齢における積算発熱量を算出する工程である。
セメント系固化材の例としては、セメント及び他の有効成分を含むものや、セメント・石灰複合系固化材等が挙げられる。
ここで、他の有効成分の例としては、高炉スラグ微粉末、石灰石粉末、フライアッシュ、シリカフューム、石膏粉末等が挙げられる。
[Step (a): Integrated calorific value calculation step]
Step (a) is a cumulative calorimeter at a predetermined material age using a calorimeter capable of detecting a change in heat of hydration reaction over time for a cement-based solidified material, a cement admixture, and a solidified material slurry containing water. It is a step of calculating the amount.
Examples of the cement-based solidified material include those containing cement and other active ingredients, cement / lime composite-based solidified material, and the like.
Here, examples of other active ingredients include blast furnace slag fine powder, limestone powder, fly ash, silica fume, gypsum powder, and the like.
セメント混和剤としては、凝結遅延剤、高性能ＡＥ減水剤、高性能減水剤、ＡＥ減水剤、減水剤、流動化剤、増粘剤等が挙げられる。
ここで、凝結遅延剤としては、オキシカルボン酸系凝結遅延剤、リグニンスルホン酸系凝結遅延剤、糖類やセルロース誘導体等の水溶性高分子からなる凝結遅延剤等が挙げられる。
高性能ＡＥ減水剤としては、ポリカルボン酸系高性能ＡＥ減水剤、ナフタリン系高性能ＡＥ減水剤、アミノスルホン酸系高性能ＡＥ減水剤、メラミン系高性能ＡＥ減水剤等が挙げられる。
高性能減水剤としては、ナフタリンスルホン酸系高性能減水剤、メラミンスルホン酸系高性能減水剤、ポリカルボン酸系高性能減水剤等が挙げられる。
Examples of the cement admixture include a setting retarder, a high-performance AE water reducing agent, a high-performance water reducing agent, an AE water reducing agent, a water reducing agent, a fluidizing agent, and a thickener.
Here, examples of the setting retarder include an oxycarboxylic acid set retarder, a lignin sulfonic acid set retarder, and a set retarder composed of a water-soluble polymer such as a saccharide or a cellulose derivative.
Examples of the high performance AE water reducing agent include polycarboxylic acid type high performance AE water reducing agent, naphthalene type high performance AE water reducing agent, aminosulfonic acid type high performance AE water reducing agent, and melamine type high performance AE water reducing agent.
Examples of the high-performance water reducing agent include a naphthalene sulfonic acid-based high-performance water reducing agent, a melamine sulfonic acid-based high-performance water reducing agent, and a polycarboxylic acid-based high-performance water reducing agent.
ＡＥ減水剤としては、リグニンスルホン酸系ＡＥ減水剤、オキシカルボン酸系ＡＥ減水剤、ポリオール系ＡＥ減水剤、ポリオキシエチレンアリルエーテル誘導体、アルキルアリルスルホン酸系ＡＥ減水剤等が挙げられる。
減水剤としては、リグニンスルホン酸系ＡＥ減水剤、オキシカルボン酸系ＡＥ減水剤、ポリオール系ＡＥ減水剤、ポリオキシエチレンアリルエーテル誘導体系ＡＥ減水剤、アルキルアリルスルホン酸系ＡＥ減水剤等が挙げられる。
流動化剤としては、ナフタレンスルホン酸系流動化剤、メラミンスルホン酸系流動化剤、ポリカルボン酸系流動化剤、ポリスチレンスルホン酸系流動化剤等が挙げられる。
増粘剤としては、セルロース系増粘剤、ポリアクリルアミド系増粘剤、アミノ酸系増粘剤、バイオポリマー系増粘剤等が挙げられる。
Examples of the AE water reducing agent include lignin sulfonic acid type AE water reducing agent, oxycarboxylic acid type AE water reducing agent, polyol type AE water reducing agent, polyoxyethylene allyl ether derivative, alkylallyl sulfonic acid type AE water reducing agent and the like.
Examples of the water reducing agent include lignin sulfonic acid AE water reducing agent, oxycarboxylic acid AE water reducing agent, polyol AE water reducing agent, polyoxyethylene allyl ether derivative AE water reducing agent, alkylallyl sulfonic acid AE water reducing agent, and the like. .
Examples of the fluidizing agent include naphthalene sulfonic acid fluidizers, melamine sulfonic acid fluidizers, polycarboxylic acid fluidizers, polystyrene sulfonic acid fluidizers, and the like.
Examples of thickeners include cellulose thickeners, polyacrylamide thickeners, amino acid thickeners, biopolymer thickeners, and the like.
水和反応熱の経時変化を検出可能な熱量計としては、材齢初期のセメント含有スラリーの水和反応熱を測定しうるものであればよく、各種のセメント水和熱測定用の伝導熱量計等が挙げられる。
積算発熱量の算出時の所定の材齢は、地盤改良土の強度発現性の予測の精度を高める観点からは、好ましくは１日以上、より好ましくは２日以上、特に好ましくは３日以上である。
該所定の材齢は、短時間で予測するという本発明の効果の観点からは、好ましくは５日以内、より好ましくは４日以内、特に好ましくは３日以内である。
As the calorimeter capable of detecting the change in heat of hydration reaction over time, any calorimeter can be used as long as it can measure the heat of hydration reaction of a cement-containing slurry at an early age. Etc.
The predetermined age at the time of calculating the cumulative calorific value is preferably 1 day or more, more preferably 2 days or more, and particularly preferably 3 days or more from the viewpoint of improving the accuracy of predicting the strength development of the ground improved soil. is there.
The predetermined age is preferably within 5 days, more preferably within 4 days, and particularly preferably within 3 days from the viewpoint of the effect of the present invention to predict in a short time.
［工程（ｂ）：強度発現性予測工程］
工程（ｂ）は、工程（ａ）で得られた積算発熱量の値に基いて、工程（ａ）における積算発熱量の算出時の材齢（工程（ａ）における所定の材齢）よりも後の材齢（以下、予測対象材齢ともいう。）における、固化材スラリーを用いた固化処理後の地盤改良土の強度発現性を予測する工程である。
ここで、予測対象材齢は、積算発熱量の算出時の材齢（工程（ａ）における所定の材齢）よりも後の材齢における強度発現性を予測しうるという利点を十分に得る観点からは、好ましくは７日以上、より好ましくは１４日以上、さらに好ましくは２１日以上、特に好ましくは２８日以上である。
該予測対象材齢は、強度発現性の予測の必要性の大きさの観点からは、好ましくは９１日以内、より好ましくは５６日以内、特に好ましくは３５日以内である。
[Step (b): Strength development property prediction step]
In the step (b), based on the value of the integrated calorific value obtained in the step (a), the age at the time of calculating the integrated calorific value in the step (a) (predetermined age in the step (a)). This is a step of predicting the strength development of the ground-improved soil after the solidification treatment using the solidification material slurry at a later age (hereinafter also referred to as a prediction target age).
Here, the prediction target material age is a viewpoint that sufficiently obtains the advantage that the strength development property at the material age after the material age at the time of calculation of the integrated calorific value (predetermined material age in the step (a)) can be predicted. Is preferably 7 days or more, more preferably 14 days or more, further preferably 21 days or more, and particularly preferably 28 days or more.
The age of the prediction target material is preferably within 91 days, more preferably within 56 days, and particularly preferably within 35 days from the viewpoint of the necessity of prediction of strength development.
本発明の好ましい実施形態の一例としては、上述の工程（ａ）〜（ｂ）に加えて、（ｃ）セメント混和剤を含まない以外は工程（ａ）の固化材スラリーと同じ材料組成を有する対照用スラリーについて、工程（ａ）（積算発熱量算出工程）と同様にして、積算発熱量を算出し、得られた値を基準値として定める基準値算出工程、を含み、かつ、工程（ｂ）（強度発現性予測工程）において、工程（ａ）の固化材スラリーについて得られた積算発熱量（Ａ）と、工程（ｃ）の対照用スラリーについて得られた上記基準値（Ｂ）との比（（Ａ）／（Ｂ）×１００（％））が、予め定めた値以上である場合に、強度発現性が良好であると予測する方法が挙げられる。
ここで、（Ａ）／（Ｂ）×１００（％）の値は、好ましくは、２０〜１００％の範囲内、より好ましくは、２５〜８０％の範囲内、さらに好ましくは、３０〜６０％の範囲内、特に好ましくは、３５〜５０％の範囲内で定めた値である。
該値が２０％以上であれば、良好な強度発現性が得られる確率（本発明の予測の信頼性）を、より高めることができる。該値が１００％以下であれば、良好と評価されるための基準が過度に厳し過ぎず、本発明の方法をより適正に実施することができる。
As an example of a preferred embodiment of the present invention, in addition to the above-described steps (a) to (b), (c) has the same material composition as the solidified material slurry of step (a) except that it does not contain a cement admixture. The control slurry includes a reference value calculation step for calculating the integrated heat generation amount and setting the obtained value as a reference value in the same manner as in step (a) (integrated heat generation amount calculation step), and including the step (b ) (Strength expression predicting step), the integrated calorific value (A) obtained for the solidified material slurry in step (a) and the reference value (B) obtained for the control slurry in step (c) A method of predicting that the strength development is favorable when the ratio ((A) / (B) × 100 (%)) is equal to or greater than a predetermined value can be mentioned.
Here, the value of (A) / (B) × 100 (%) is preferably within a range of 20 to 100%, more preferably within a range of 25 to 80%, and even more preferably 30 to 60%. In particular, it is a value determined within a range of 35 to 50%.
If this value is 20% or more, the probability of obtaining good strength development (reliability of prediction of the present invention) can be further increased. If this value is 100% or less, the criteria for being evaluated as good are not excessively strict, and the method of the present invention can be implemented more appropriately.
以下、実施例に基いて本発明を説明するが、本発明は実施例に限定されるものではない。
［実験例１〜９］
（１）対象土
対象土として、表１に示すものを用いた。
（２）セメント系固化材
セメント系固化材として、特殊土用固化材（太平洋セメント社製、商品名：ジオセット２００）を用いた。この固化材は、セメント、硫酸塩等を含むものである。
（３）セメント混和剤
セメント混和剤として、表２に示すものを用いた。
表２中の「オキシカルボン酸」、「ポリカルボン酸」、「リグニンスルホン酸」は、各々、以下のセメント混和剤を表す。
オキシカルボン酸：地盤改良用のオキシカルボン酸系凝結遅延剤（ＢＡＳＦジャパン社製、商品名：レオソイル３００Ｋ）
ポリカルボン酸：ポリカルボン酸系高性能ＡＥ減水剤（ＢＡＳＦジャパン社製、商品名：マスターグレニウムＳＰ８ＳＶ）
リグニンスルホン酸：リグニンスルホン酸系ＡＥ減水剤（ＢＡＳＦジャパン社製、商品名：ポゾリスＮｏ．７０）
（４）固化材ペーストの調製
表２に示す配合で、セメント系固化材、セメント混和剤、及び純水からなる固化材ペーストを調製した。
EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to an Example.
[Experimental Examples 1-9]
(1) Target soil The target soil shown in Table 1 was used.
(2) Cement-based solidifying material As a cement-based solidifying material, a special soil solidifying material (trade name: Geoset 200, manufactured by Taiheiyo Cement Co., Ltd.) was used. This solidifying material contains cement, sulfate and the like.
(3) Cement admixture The cement admixture shown in Table 2 was used.
In Table 2, “oxycarboxylic acid”, “polycarboxylic acid”, and “lignin sulfonic acid” each represent the following cement admixture.
Oxycarboxylic acid: An oxycarboxylic acid-based setting retarder for improving ground (BASF Japan, trade name: Leosoyl 300K)
Polycarboxylic acid: polycarboxylic acid-based high-performance AE water reducing agent (manufactured by BASF Japan, trade name: Master Grenium SP8SV)
Lignin sulfonic acid: lignin sulfonic acid-based AE water reducing agent (manufactured by BASF Japan, trade name: Pozzolith No. 70)
(4) Preparation of solidification material paste The solidification material paste which consists of a cement-type solidification material, a cement admixture, and a pure water by the mixing | blending shown in Table 2 was prepared.
（５）積算発熱量の算出
前記（４）で調製した固化材ペーストについて、微小熱量計（東京理工社製、商品名「ＭＭＣ−５１１Ｃ６」）を用いて、材齢３日（７２時間）までの水和発熱速度を測定し、その測定結果に基いて、材齢３日の時点における積算発熱量（Ｊ／時間（ｈｒ））を算出した。測定時の室温は２０℃であった。
（６）材齢２８日の一軸圧縮強さの測定
表２に示すとおり、対象土に対して、対象土１ｍ３当たり３００ｋｇの量のセメント系固化材を、水／セメント系固化材の比が１００質量％であるスラリー（ただし、スラリー中の水の一部を表２に示す割合でセメント混和剤と置換した。）として添加して、ソイルミキサ内にて混合し、混合物を得た。この混合物を用いて、ＪＧＳ−０８２１に規定する「安定処理土の締固めをしない供試体作製方法」に準じて、供試体を作製した。次いで、この供試体を封緘養生（２０℃、７０％相対湿度）して、模擬の地盤改良土を得た。
得られた模擬の地盤改良土について、「ＪＩＳ Ａ １２１６：２００９」（土の一軸圧縮試験方法）に規定されている方法を用いて、材齢２８日の一軸圧縮強さ（ｋＮ／ｍ２）を測定した。
(5) Calculation of integrated calorific value For the solidified material paste prepared in (4) above, using a microcalorimeter (trade name “MMC-511C6”, manufactured by Tokyo Riko Co., Ltd.), until the material age is 3 days (72 hours). The heat generation rate of hydration was measured, and based on the measurement results, the cumulative calorific value (J / hour (hr)) at the age of 3 days was calculated. The room temperature at the time of measurement was 20 ° C.
(6) As shown in the measurement table 2 uniaxial compressive strength at the age of 28 days, to a subject's earth, cement-based solidifying material amount of the target soil 1 m 3 per 300 kg, the ratio of water / cement solidifying material It was added as a slurry of 100% by mass (however, a part of water in the slurry was replaced with a cement admixture at a ratio shown in Table 2) and mixed in a soil mixer to obtain a mixture. Using this mixture, a specimen was prepared in accordance with “Method for preparing specimen without compaction of stabilized soil” defined in JGS-0821. Next, this specimen was sealed (20 ° C., 70% relative humidity) to obtain a simulated ground improvement soil.
About the obtained simulated ground improvement soil, using the method prescribed | regulated to "JIS A1216: 2009" (uniaxial compression test method of soil), the unconfined compressive strength (kN / m < 2 >) of material age 28 days Was measured.
［対照実験例］
セメント混和剤を用いない以外は実験例１と同様にして、実験した。
以上の結果を表２に示す。
[Control experiment example]
The experiment was performed in the same manner as in Experimental Example 1 except that no cement admixture was used.
The results are shown in Table 2.
表２から、以下のことがわかる。
対照実験例における材齢３日の積算発熱量（１７５Ｊ／ｈｒ）を基準値（１００％）とした場合、実験例１、４〜７では、材齢３日の積算発熱量が、この基準値（１００％）に対する比で３５％以上であるため、材齢２８日の一軸圧縮強さとして、対照実験例の値（１６１０ｋＮ／ｍ２）を超える値（１６３０〜１８７０ｋＮ／ｍ２）を得ている。
一方、実験例２〜３、８〜９では、材齢３日の積算発熱量が、この基準値（１００％）に対する比で３５％を下回るため、材齢２８日の一軸圧縮強さとして、対照実験例の値（１６１０ｋＮ／ｍ２）よりも小さな値（８９１〜１３８０ｋＮ／ｍ２）を得ている。
このことから、材齢３日の積算発熱量が、基準値（１００％）に対する比で３５％以上であるか否かによって、強度発現性の良否（材齢２８日の一軸圧縮強さが大きいか否か）を予測しうることがわかる
Table 2 shows the following.
When the cumulative calorific value (175 J / hr) at the age of 3 days in the control experimental example is taken as the reference value (100%), in the experimental examples 1, 4 to 7, the cumulative calorific value at the age of 3 days is the reference value. Since the ratio with respect to (100%) is 35% or more, the value (1630-1870 kN / m 2 ) exceeding the value (1610 kN / m 2 ) of the control experiment example was obtained as the uniaxial compressive strength at the age of 28 days. Yes.
On the other hand, in Experimental Examples 2-3 and 8-9, since the accumulated calorific value at the age of 3 days is less than 35% in a ratio to this reference value (100%), as the uniaxial compressive strength at the age of 28 days, A value (891-1380 kN / m 2 ) smaller than the value of the control experiment example (1610 kN / m 2 ) is obtained.
From this, whether or not the accumulated calorific value at the age of 3 days is 35% or more by the ratio with respect to the reference value (100%), the strength expression is good (uniaxial compressive strength at the age of 28 days is large). Can be predicted)
Claims (5)
上記積算発熱量の値に基いて、上記所定の材齢よりも後の材齢における、上記固化材スラリーを用いた固化処理後の地盤改良土の強度発現性を予測する強度発現性予測工程、
を含むことを特徴とする地盤改良土の強度発現性の予測方法。 Calculating integrated calorific value for a solidified material slurry containing cement-based solidified material, cement admixture, and water, using a calorimeter capable of detecting changes over time in the heat of hydration reaction, for a given material age Process and
Based on the value of the integrated calorific value, a strength development predicting step for predicting the strength development of the ground improved soil after the solidification treatment using the solidified slurry in the age after the predetermined age,
A method for predicting the strength development of ground improved soil, comprising
上記強度発現性予測工程において、上記固化材スラリーについて得られた上記積算発熱量（Ａ）と、上記対照用スラリーについて得られた上記基準値（Ｂ）との比（（Ａ）／（Ｂ）×１００（％））が、予め定めた値以上である場合に、上記強度発現性が良好であると予測する、請求項１又は２に記載の地盤改良土の強度発現性の予測方法。 For the control slurry having the same material composition as the solidifying material slurry except that the cement admixture is not included, the integrated calorific value is calculated in the same manner as the integrated calorific value calculating step, and the obtained value is the reference value. Including a reference value calculation step defined as
In the strength development predicting step, a ratio ((A) / (B) between the integrated calorific value (A) obtained for the solidified material slurry and the reference value (B) obtained for the control slurry. The prediction method of the strength development property of the ground improvement soil according to claim 1 or 2 which predicts that said strength development property is favorable when x100 (%)) is more than a predetermined value.
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