JP2007051492A - Checking method for soil improvement effect, and grouting method using the same - Google Patents
Checking method for soil improvement effect, and grouting method using the same Download PDFInfo
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本発明は溶液型シリカグラウト、特に非アルカリ性シリカグラウトを用いた薬液注入の地盤改良効果の確認方法に係り、詳細には注入後の注入率と改良地盤の固結状況を把握し、更には改良地盤の固結範囲と固結状況の分布を確認して地盤改良効果の確認を行う地盤改良効果の確認方法およびこの方法を用いた地盤注入工法である。 The present invention relates to a method for confirming the ground improvement effect of chemical injection using solution-type silica grout, particularly non-alkaline silica grout. Specifically, the injection rate after injection and the consolidation status of the improved ground are grasped and further improved. This is a ground improvement effect confirmation method for confirming the ground improvement effect by confirming the distribution of the consolidation range and consolidation status of the ground, and a ground injection method using this method.
近年、液状化防止や基礎の補強工事が長期耐久性のあるシリカ溶液を用いた地盤注入工法で行われるようになり、注入地盤の効果の確認方法が極めて重要になってきた。なぜならば、薬液注入が本設工事に使用される以上、注入材そのものが長期耐久性に優れていること、適用する注入工法の土粒子間浸透が可能であり、かつ注入孔間隔を広く取って広範囲の浸透固結による経済的施工が可能であることが必要である。 In recent years, liquefaction prevention and foundation reinforcement work has been carried out by a ground injection method using a silica solution having a long-term durability, and a method for confirming the effect of the injection ground has become extremely important. This is because, as long as chemical injection is used in the main construction, the injection material itself is excellent in long-term durability, and it is possible to penetrate between the soil particles of the applied injection method and widen the injection hole interval. It is necessary to be able to perform economical construction by wide-range penetration consolidation.
従来の効果の確認方法としては、標準貫入試験や透水試験等の現位置試験が用いられてきた。しかし、液状化防止等の本設工事では注入後液状化強度に対応した一軸圧縮強度の把握を注入地盤のコアサンプリングによって行うのが一般的である。 As a conventional method for confirming the effect, in-situ tests such as a standard penetration test and a water permeability test have been used. However, in the construction work such as liquefaction prevention, it is common to grasp the uniaxial compressive strength corresponding to the liquefaction strength after injection by core sampling of the injected ground.
一方、不撹乱試料の採取は現地盤に礫等が介在していると一軸圧縮強度のためのコア採取が不可能な場合が多い。 On the other hand, when undisturbed samples are collected, there are many cases where it is not possible to collect cores due to uniaxial compressive strength if gravel or the like is present on the local board.
また、従来の仮設用地盤注入では注入孔間隔は1m程度であったが、近年本設施工のためには経済的施工が必要であることから注入孔間隔は1.5〜4mとして柱状浸透注入工法や多点同時注入工法によって長い浸透距離が可能な注入工法が本出願人などによって発明されている。 In addition, in the conventional temporary ground injection, the interval between the injection holes was about 1 m. However, in recent years, economical construction is necessary for the main construction, so the interval between the injection holes is set to 1.5 to 4 m. The present applicant has invented an injection method capable of a long penetration distance by the multi-point simultaneous injection method.
一方、広範囲な注入においては注入孔からの距離が長くなるにつれて浸透固結した強度が低減する分布を示すことがわかってきた。このような注入目的の注入効果の確認方法としてのコアサンプリングによるコアを採取することの困難さとサンプリング数に限度があること、整形しにくい等の問題があった。 On the other hand, it has been found that in a wide range of injections, the permeation and consolidation strength decreases as the distance from the injection hole increases. As a method for confirming the injection effect for such injection purposes, there have been problems such as difficulty in collecting cores by core sampling, a limited number of samplings, and difficulty in shaping.
そこで固結土中の薬液の含有量を測定し、不撹乱試料を必要としない化学分析によって薬液の主成分であるSiO2やNa2Oを固結土から溶出させて定量する方法がある。 So by measuring the content of caking soil chemical, S i O 2 and Na 2 method O was eluted from the consolidated soil is quantified as the main component of the chemical by chemical analysis that does not require undisturbed sample is there.
しかし固結土中のSiO2の測定から含有量を求める方法では、土粒子に含まれる非晶質のシリカ分も測定されてしまう。現地盤中の非晶質のシリカ分がシリカグラウト中のシリカ分と必ずしも同じ性質のものとは限らないし、これら双方のシリカを分けて検出することは可能であるが、それには複雑な処理過程や高い技術が必要となるので実用的とはいえず、たとえシリカグラウト中のシリカ分を分析してもその分析法におけるシリカ分の測定値が固結地盤に注入されているシリカ分の絶対値を示しているとは限らない。 However, in the method of obtaining the content from the measurement of S i O 2 in the consolidated soil, the amorphous silica content contained in the soil particles is also measured. The amorphous silica content in the local board is not necessarily the same as the silica content in the silica grout, and it is possible to detect both types of silica separately, but this is a complicated process. However, even if the silica content in the silica grout is analyzed, the measured silica content is the absolute value of the silica content injected into the consolidated ground. It does not always indicate.
また、固結土中のNa2Oの測定から含有量を求める方法では、地盤中で硬化したゲルのNa2Oは可溶性成分として存在しており、地盤中の水により移動しやすいことや、海水の影響のある地盤ではシリカグラウトの水ガラスに起因するNa2Oと海水のNa2Oとの区別ができず使用できないこと等の問題があった。
本発明では薬液注入における地盤改良後の注入効果の確認を行う方法として、改良地盤の固結土中のシリカ含有量を求めて注入対象地盤への薬液の注入率を把握するものである。ここで、注入率とは、注入対象土量の単位体積当りに注入するグラウト量の割合を百分率で表したもので、注入効果並びに強度発現に著しい影響を与えるものである。 In the present invention, as a method for confirming the injection effect after the ground improvement in the chemical solution injection, the silica content in the consolidated soil of the improved ground is obtained to grasp the injection rate of the chemical solution into the injection target ground. Here, the injection rate is the percentage of the amount of grout injected per unit volume of the amount of soil to be injected, expressed as a percentage, which significantly affects the injection effect and strength development.
しかし、前記の化学分析方法によって得られた改良地盤の固結土のみの測定によるシリカ含有量の測定値は様々な不確定要因を含む値であり、改良地盤に注入されたシリカ含有量の絶対値を示すものではない。 However, the measured value of the silica content by measuring only the solid soil of the improved ground obtained by the above chemical analysis method is a value including various uncertain factors, and the absolute value of the silica content injected into the improved ground It does not indicate a value.
従って、薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して、存在する空隙をすべて注入液で充填した場合を注入率100%として供試体を作製し、その供試体の単位体積当りのシリカ含有量を注入率100%とみなして基準とし、地盤改良後の固結土の単位体積当りのシリカ含有量の基準値に対する割合から注入率を算定する方法、または薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%になるように供試体を作製するに要した薬液から算出したシリカ含有量を注入率100%とみなして基準とし、地盤改良後の固結土の単位体積あたりのシリカ含有量から地盤の非晶質のシリカ含有量を差し引き、基準値に対する割合から注入率を算定する方法の2通りの方法により、前記の不確定要因と関係なく注入率を算出して前記の問題を解決し、簡便かつ正確な地盤改良効果を確認する方法を確立して信頼性の高い地盤改良を行うことを課題とする。 Therefore, by adjusting the relative density of the ground using sand collected from the ground before chemical injection, a test specimen was prepared with an injection rate of 100% when all the existing voids were filled with the injected liquid. A method that calculates the injection rate from the ratio of the silica content per unit volume of the consolidated soil after ground improvement to the reference value, assuming the silica content per unit volume as 100% injection rate, or before chemical solution injection Silica calculated from the chemical solution required to prepare the specimen so that the injection rate is 100% when all the voids existing by adjusting the relative density of the ground using sand collected from the ground are filled with the injection solution Subtracting the amorphous silica content of the ground from the silica content per unit volume of the consolidated soil after ground improvement and calculating the injection rate from the ratio to the reference value 2 ways to do To solve the above problems by calculating the injection rate regardless of the uncertain factors, and to establish a simple and accurate method for confirming the ground improvement effect, and to perform highly reliable ground improvement And
第一の発明では、薬液注入後の改良地盤から採取した固結土の単位体積当りのシリカ含有量を測定し、薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%として作製した供試体の単位体積当りのシリカ含有量に対する割合から注入率を求める方法を前記課題の解決手段とした。 In the first invention, the silica content per unit volume of consolidated soil collected from the improved ground after chemical solution injection is measured and adjusted to the relative density of the ground using sand collected from the ground before chemical solution injection. A method for obtaining the injection rate from the ratio to the silica content per unit volume of a specimen prepared with an injection rate of 100% when all the existing voids were filled with the injection solution was used as a means for solving the above problems.
第二の発明では、薬液注入後の改良地盤から採取した固結土の単位体積当りのシリカ含有量を測定し、これより薬液注入前の地盤の非晶質のシリカ含有量を差し引き、薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%になるように供試体を作製するに要した薬液から算出したシリカ含有量に対する割合から注入率を求める方法を前記課題の解決手段とした。 In the second invention, the silica content per unit volume of the consolidated soil collected from the improved ground after the chemical solution injection is measured, and the amorphous silica content of the ground before the chemical solution injection is subtracted from this, the chemical solution injection It was calculated from the chemical solution required to prepare the specimen so that the injection rate was 100% when all the voids existing by adjusting the relative density of the ground using sand collected from the previous ground were filled with the injection solution The method for obtaining the injection rate from the ratio with respect to the silica content was used as a means for solving the above problems.
第三の発明では、第一、第二の発明の方法を用いて求めた注入率から、注入後の固結状況や地盤改良範囲の固結状況の分布を確認する地盤改良効果の確認方法を前記課題の解決手段とした。 In the third invention, a ground improvement effect confirmation method for confirming the distribution of consolidation status after injection and consolidation status in the ground improvement range from the injection rate obtained using the methods of the first and second inventions. Means for solving the above-described problems were provided.
第四の発明では、第一、第二の発明の方法を用いて求められる注入率から地盤改良範囲および注入後の固結状況を確認する工程を含む地盤注入工法を前記課題の解決手段とした。 In the fourth invention, the ground injection construction method including the step of confirming the ground improvement range and the consolidation status after the injection from the injection rate obtained by using the methods of the first and second inventions is defined as a solution to the above problem. .
本発明の注入率を求める方法によれば、請求項1記載の薬液注入後の改良地盤から採取した固結土の単位体積当りのシリカ含有量を測定し、薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%として作製した供試体の単位体積当りのシリカ含有量に対する割合から注入率を求める。 According to the method for determining the injection rate of the present invention, the silica content per unit volume of the consolidated soil collected from the improved ground after the chemical solution injection according to claim 1 is measured, and the sand collected from the ground before the chemical solution injection. The filling rate is determined from the ratio of the test specimens prepared with the filling rate of 100% when all the existing voids are adjusted to the relative density of the ground using, and the filling rate is 100%.
また、請求項2記載の薬液注入後の改良地盤から採取した固結土の単位体積当りのシリカ含有量を測定し、これより地盤の非晶質のシリカ含有量を差し引き、地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%になるように供試体を作製するに要した薬液から算出したシリカ含有量に対する割合から注入率を求める。 Further, the silica content per unit volume of the consolidated soil collected from the improved ground after the chemical solution injection according to claim 2 is measured, and the amorphous silica content of the ground is subtracted therefrom, and the sand collected from the ground. Injecting from the ratio to the silica content calculated from the chemical solution required to prepare the specimen so that the injection rate is 100% when all the existing voids are adjusted to the relative density of the ground using Find the rate.
さらにまた、薬液注入前の地盤から採取した砂を用いて注入率100%として作製した供試体並びに薬液注入前の地盤から採取した砂の相対密度は地盤の相対密度と同一にすることを特徴とするから、簡便かつ正確な薬液注入における地盤改良後の注入効果の確認方法を確立することができ、信頼性の高い施工管理を行うことができる。 Furthermore, it is characterized in that the relative density of the specimen collected from the ground before the chemical solution injection and the sand sampled from the ground before the chemical solution injection is made the same as the relative density of the ground. Therefore, a method for confirming the injection effect after ground improvement in simple and accurate chemical injection can be established, and highly reliable construction management can be performed.
本発明に使用する溶液型シリカグラウトは、浸透性に優れ、ゲル化時間が長く、耐久性に優れており、広い注入範囲への浸透固結による経済的施工が可能なグラウトであり、水ガラスを素材とするグラウトであって、水ガラスと反応剤からなる水ガラスグラウトである。 The solution-type silica grout used in the present invention is a grout having excellent permeability, long gel time, excellent durability, and capable of economical construction by osmotic consolidation in a wide injection range. A water glass grout made of water glass and a reactant.
好ましい具体例としては、(1)水ガラスと酸を混合して脱アルカリした酸性シリカ溶液、(2)水ガラスをイオン交換樹脂処理またはイオン交換膜処理によって脱アルカリして得られるシリカ溶液、(3)水ガラスを脱アルカリ処理して酸性シリカ溶液とし、これにアルカリ材を添加して中性〜アルカリ性としたシリカ溶液、(4)水ガラスを脱アルカリ処理して得られるシリカ溶液または水ガラスを脱アルカリ処理して得られる酸性シリカ溶液にアルカリ材を添加して中性〜アルカリ性としたシリカ溶液を再度脱アルカリ処理して得られる酸性シリカ溶液、(5)水ガラスを脱アルカリ処理して酸性シリカ溶液とし、これを濃縮増粒して得られる安定化されたコロイダルシリカ溶液、(6)水ガラスとコロイダルシリカとを混合して得られるそれ自体自硬性のない安定化したシリカ溶液を脱アルカリして得られる酸性シリカ溶液、(7)水ガラスとコロイダルシリカと水ガラスを脱アルカリ処理して得られるシリカ溶液とを混合して得られるそれ自体自硬性のない安定化したシリカ溶液を脱アルカリして得られる酸性シリカ溶液等が挙げられる。 Preferable specific examples include (1) acidic silica solution obtained by dealkalizing water glass and acid, (2) silica solution obtained by dealkalizing water glass by ion exchange resin treatment or ion exchange membrane treatment, 3) Water glass is dealkalized to an acidic silica solution, and an alkali material is added thereto to make it neutral to alkaline. (4) Silica solution or water glass obtained by dealkalizing water glass Acidic silica solution obtained by dealkalizing again the silica solution made neutral to alkaline by adding an alkali material to the acid silica solution obtained by dealkalizing, and (5) dealkalizing the water glass Stabilized colloidal silica solution obtained by concentrating and increasing the size of acidic silica solution, (6) No self-hardening obtained by mixing water glass and colloidal silica Acidic silica solution obtained by dealkalizing a standardized silica solution, (7) No self-hardening obtained by mixing water glass, colloidal silica, and silica solution obtained by dealkalizing water glass Examples thereof include acidic silica solutions obtained by dealkalizing a stabilized silica solution.
前記のシリカ溶液にさらにゲル化調整剤を添加することもできる。このゲル化調整剤としては、硫酸、リン酸、硫酸塩化アルミニウム、ポリ塩化アルミニウム、硫酸バンド、有機酸(クエン酸、コハク酸、酢酸)等、水溶液中に溶解して酸性を呈する酸性反応剤、アルカリ金属塩、アルカリ土金属塩等の無機塩類等が挙げられる。この中で特に、クエン酸や縮合リン酸塩等の金属イオン封鎖剤やリン酸系化合物は地盤中のコンクリート構造物や土中の微量金属に不溶性被覆膜を形成してマスキング作用によってアルカリの溶出を封鎖するため、コンクリートを保護する効果がある。 A gelling modifier can be further added to the silica solution. Examples of the gelation modifier include sulfuric acid, phosphoric acid, aluminum sulfate chloride, polyaluminum chloride, sulfate bands, organic acids (citric acid, succinic acid, acetic acid), etc. Examples include inorganic salts such as alkali metal salts and alkaline earth metal salts. Among these, sequestering agents and phosphate compounds such as citric acid and condensed phosphates form an insoluble coating film on the concrete structure in the ground and trace metals in the soil, and the alkali action by masking action. Since the leaching is blocked, the concrete is protected.
金属イオン封鎖材としては、具体的にはクエン酸、グルコン酸等の脂肪族オキシカルボン酸、ピロリン酸、トリリン酸、トリメタリン酸等の縮合リン酸塩、ポリリン酸ナトリウム、酸性ポリリン酸ナトリウム、トリポリリン酸ナトリウム、テトラポリリン酸ナトリウム、ヘキサメタリン酸ナトリウム、酸性ヘキサメタリン酸ナトリウムまたはこれらのカリウム塩等のポリリン酸塩、その他にエチレンジアミン四酢酸、ニトリロトリ酢酸及びこれらの塩類等が挙げられる。 Specific examples of the sequestering material include aliphatic oxycarboxylic acids such as citric acid and gluconic acid, condensed phosphates such as pyrophosphoric acid, triphosphoric acid and trimetaphosphoric acid, sodium polyphosphate, acidic sodium polyphosphate and tripolyphosphoric acid. Examples thereof include polyphosphates such as sodium, sodium tetrapolyphosphate, sodium hexametaphosphate, acidic sodium hexametaphosphate or potassium salts thereof, ethylenediaminetetraacetic acid, nitrilotriacetic acid, and salts thereof.
薬液注入地盤の注入率を求める方法として、一つは注入率を求めたい薬液注入後の地盤から採取した相対密度b%、質量Mb〔g〕、体積Vb〔cm3〕、密度ρb=Mb/Vb〔g/cm3〕の固結土と、薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%として作製した相対密度b%、質量Ma〔g〕、体積Va〔cm3〕、密度ρa=Ma/Va〔g/cm3〕の供試体の2種類の試料についてシリカの分析を行い、それぞれ試料1〔g〕当りのシリカ含有量〔mg〕を測定し、注入率100%として作製した供試体の1〔g〕当りのシリカ含有量A’〔mg /g〕、薬液注入後の地盤から採取した固結土のシリカ含有量B’〔mg/g〕にそれぞれの密度ρa、ρbを乗じて単位体積当りのシリカ含有量A〔mg/cm3〕、B〔mg/cm3〕を求め、注入率100%として作製した供試体の単位体積当りのシリカ含有量を基準として、これに対する改良地盤から採取した固結土の単位体積当りのシリカ含有量の割合から注入率λを求める。前記の内容を簡単に式で表すと、λ=(B’ ・ρb)/(A’ ・ρa)×100=B/A×100〔%〕(式1.1)となる。 As a method for obtaining the injection rate of the chemical solution injection ground, one is the relative density b%, mass M b [g], volume V b [cm 3 ], density ρ b collected from the ground after the chemical injection for which the injection rate is desired to be obtained. = M b / V b [g / cm 3 ] consolidated soil and sand collected from the ground before chemical injection, adjusted to the relative density of the ground and filled with all the existing voids Two types of specimens with a relative density of b%, mass M a [g], volume V a [cm 3 ], density ρ a = M a / V a [g / cm 3 ], produced at an injection rate of 100% The silica content [mg] per 1 [g] of the specimens prepared by measuring the silica content [mg] per 1 [g] and measuring the silica content [mg] per 100 [g] ], of each of the silica content of the caking soil collected from the ground after chemical injection B '[mg / g] density [rho a, the [rho b Flip silica content A per unit volume [mg / cm 3] to obtain the B [mg / cm 3], the silica content per unit volume of the specimen prepared as an infusion rate of 100% as a reference, against which The injection rate λ is obtained from the ratio of the silica content per unit volume of consolidated soil collected from the improved ground. When the above content is simply expressed by an equation, λ = (B ′ · ρ b ) / (A ′ · ρ a ) × 100 = B / A × 100 [%] (Equation 1.1).
二つ目の方法としては、注入率を求めたい薬液注入後の地盤から採取した相対密度b%、質量Mb〔g〕、体積Vb〔cm3〕、密度ρb=Mb/Vb〔g/cm3〕の固結土と薬液注入前の地盤から採取した砂の2種類の試料についてシリカの分析を行い、それぞれ試料1〔g〕当りのシリカ含有量を測定し、薬液注入後の地盤から採取した固結土のシリカ含有量B’〔 mg /g〕に密度ρbを乗じて単位体積当りのシリカ含有量B〔mg/cm3〕を求め、これより砂から溶出したシリカ含有量D’〔 mg/g〕に相対密度b%のときの土の乾燥密度ρdを乗じて求めた単位体積当りのシリカ含有量D〔mg/cm3〕を差し引き、薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整して存在する空隙をすべて注入液で充填した場合を注入率100%になるように作製した相対密度b%、質量Mc〔g〕、体積Vc〔cm3〕の供試体に要する薬液(質量McG)のシリカ濃度C’〔%〕にMcG/Vcを乗じて求めた単位体積当りのシリカ含有量C〔mg/cm3 〕を基準として、これに対する割合から注入率を求める。前記の内容を簡単に式で表すと、λ=(B’ ・ρb−D’ ・ρd)/{(C’/100)×(McG/Vc)×1000}×100=(B‐D)/C×100〔%〕(式1.2)となる。 As a second method, the relative density b%, mass M b [g], volume V b [cm 3 ], density ρ b = M b / V b collected from the ground after the chemical injection for which the injection rate is desired to be obtained. Silica was analyzed for 2 types of samples of solid soil of [g / cm 3 ] and sand collected from the ground before chemical injection, and the silica content per 1 [g] of each sample was measured, and after chemical injection determine the silica content B per unit volume [mg / cm 3] is multiplied by the silica content B '[mg / g] to the density [rho b of caking soil collected from the ground, the silica eluted from this sand Subtract the silica content D [mg / cm 3 ] per unit volume obtained by multiplying the content D '[mg / g] by the soil dry density ρ d when the relative density is b%, and then the ground before chemical injection The case where all the voids that exist by adjusting the relative density of the ground using sand collected from M with a silica concentration C ′ [%] of a chemical solution (mass M cG ) required for a specimen having a relative density of b%, mass M c [g], and volume V c [cm 3 ] produced so that the injection rate is 100%. based on the cG / V c obtained by multiplying by silica content per unit volume calculated C [mg / cm 3] to determine the injection rate as a percentage of this. The above contents can be simply expressed by an equation: λ = (B ′ · ρ b −D ′ · ρ d ) / {(C ′ / 100) × (M cG / V c ) × 1000} × 100 = (B -D) / C × 100 [%] (Formula 1.2).
従来は薬液注入後の地盤から採取した固結土のシリカ含有量の測定値B’〔mg/g〕のみから注入後の地盤改良効果を判断していたが、前期の方法を用いればより正確な注入率が求められ、注入後の地盤改良効果の確認がより確実となる。従って、前記の方法によるシリカ含有量の測定から求められた注入率と設計注入率とを比較することによって、更には薬液注入前の地盤から採取した砂を用いて地盤の相対密度に調整し、存在する空隙をすべて注入液で充填した場合を注入率100%として作製した供試体の強度から薬液注入後の地盤の強度を推定することができ、設計強度と比較することによって地盤改良効果を充分に評価できる。 Previously, the soil improvement effect after injection was judged only from the measured value B ′ [mg / g] of the silica content of the consolidated soil collected from the ground after the chemical injection. A high injection rate is required, and confirmation of the ground improvement effect after injection is more certain. Therefore, by comparing the injection rate obtained from the measurement of the silica content by the above method and the design injection rate, further adjusting the relative density of the ground using sand collected from the ground before chemical injection, The strength of the ground after the chemical solution injection can be estimated from the strength of the specimen prepared with an injection rate of 100% when all the existing voids are filled with the injection rate, and the ground improvement effect is sufficient by comparing with the design strength Can be evaluated.
以下、本発明を実施例によって説明するが、本発明はこれらの実施例に限定されるものではない。
シリカ含有量の測定方法
(1)シリカ含有量測定用試料液の作製方法
試料を105℃の高温室へ2時間入れて乾燥させる。乾燥した試料から5gを採取し、10%の水酸化ナトリウム(NaOH)溶液20mlと純水50mlを加えて1時間撹拌を行った後、ろ紙でろ過し、ろ紙上の試料分を純水で洗浄しながらろ液を作り、得られたろ液に水を加えて250mlとしてシリカ含有量測定用供試液を作製した。その際、試料を乾燥させた際の乾燥減量〔%〕を式2.1にて求めた。
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
Method for Measuring Silica Content (1) Method for Preparing Sample Solution for Measuring Silica Content Place the sample in a high temperature chamber at 105 ° C for 2 hours and dry. Collect 5 g from the dried sample, add 20 ml of 10% sodium hydroxide (NaOH) solution and 50 ml of pure water, stir for 1 hour, filter with filter paper, and wash the sample on the filter paper with pure water While making a filtrate, water was added to the obtained filtrate to prepare a test solution for measuring the silica content to 250 ml. At that time, the loss on drying [%] when the sample was dried was determined by Formula 2.1.
ここで、 G:乾燥減量〔%〕
E:乾燥前の試料の重量〔g〕
F:乾燥後の試料の重量〔g〕
Where G: Loss on drying [%]
E: Weight of sample before drying [g]
F: Weight of sample after drying [g]
(2)測定方法
ICP-AES(誘導結合プラズマ発光分光分析)によりSiを測定した。Si からSiO2を式2.2により換算して求めた。
(2) Measurement method
Si was measured by ICP-AES (inductively coupled plasma emission spectroscopy). SiO 2 was converted from Si 2 according to Formula 2.2.
ここで、ICP-AESは、物質中の成分をプラズマ発光させて分光することによって元素を分析するものであり、金属、ガラス、セラミック、紙、繊維、洗浄加工水、工業排水などの主成分元素・微量成分元素を高感度・高精度で定性・定量することができる。特に微量元素の分析に有効である。 Here, ICP-AES analyzes elements by plasma emission and spectroscopy of components in a substance, and it is a main component element such as metal, glass, ceramic, paper, fiber, cleaning processed water, industrial wastewater, etc. -Trace element elements can be qualitatively and quantitatively analyzed with high sensitivity and high accuracy. It is particularly effective for analysis of trace elements.
ここで、J:試料液1L当りのSiO2量〔mg〕
H:試料液1L当りのSi量〔mg〕
Here, J: SiO 2 amount per liter of sample solution [mg]
H: Amount of Si per liter of sample solution [mg]
(4)試料1g当たりのSiO2量の求め方
式2.3より試料1g当たりのSiO2量を求めた。
(4) was determined SiO 2 per sample 1g than Determination of formula 2.3 SiO 2 per sample 1g.
ここで、 K:試料1g当りのSiO2〔mg/g〕
J:試料液1〔L〕当りのSiO2〔mg/L〕
l:試料液量(250〔ml〕)
m:測定に用いた乾燥試料の重量(5〔g〕)
G:乾燥減量〔%〕
Here, K: SiO 2 [mg / g] per 1 g of sample
J: SiO 2 [mg / L] per 1 [L] of the sample liquid
l: Sample liquid volume (250 [ml])
m: Weight of dry sample used for measurement (5 [g])
G: Loss on drying [%]
注入率を求める際の相対密度による影響を把握するために、豊浦標準砂とシリカ濃度4、5、6%の溶液型非アルカリ性シリカゾルグラウトを用い、相対密度40%、80%で注入率100%の供試体を作製して相対密度と強度、相対密度とシリカ含有量の関係を求めた。 In order to understand the influence of relative density when determining the injection rate, Touraura standard sand and solution type non-alkaline silica sol grout with silica concentration of 4, 5 and 6% are used, and injection rate is 100% at relative density of 40% and 80%. Samples were prepared and the relationship between relative density and strength, and relative density and silica content were determined.
(1)薬液
表1示す溶液型非アルカリ性シリカグラウトを用いた。
この、溶液型非アルカリ性シリカグラウトは水ガラスをイオン交換により脱アルカリして得られる活性シリカ(SiO2濃度4Wt%)をベースとし、それに水ガラスと酸(リン酸)によって所定のシリカ濃度とpHに調整した酸性シリカ溶液である。
(1) Chemical solution The solution type non-alkaline silica grout shown in Table 1 was used.
This solution-type non-alkaline silica grout is based on activated silica (SiO 2 concentration 4 Wt%) obtained by dealkalizing water glass by ion exchange, and it has a predetermined silica concentration and pH by water glass and acid (phosphoric acid). It is the acidic silica solution adjusted to.
ここで、活性シリカの代わりにコロイダルシリカをベースにして用いてもよいし、水ガラスと酸を加えて水ガラスのアルカリを除去して得られた酸性シリカゾルからなる酸性シリカ溶液を用いてもよい。 Here, instead of active silica, colloidal silica may be used as a base, or an acidic silica solution composed of an acidic silica sol obtained by adding water glass and an acid to remove the alkali of the water glass may be used. .
(2)試料砂
豊浦標準砂
(3)供試体の作製
内径50mm、高さ100mmのモールドを用いて供試体を作製した。
(2) Sample sand Toyoura standard sand
(3) Preparation of specimen A specimen was prepared using a mold having an inner diameter of 50 mm and a height of 100 mm.
(4)強度並びにシリカ含有量の測定
供試体の一軸圧縮強度を測定し、強度を測定し終えた固結砂のシリカ含有量を前記のシリカ含有量の測定方法により分析し、供試体の質量に対するシリカ含有量の割合で表した。また、供試体からは薬液のシリカと試料砂のシリカが溶出されるので、試料砂のみのシリカ含有量も測定してブランクとした。
(4) Measurement of strength and silica content The uniaxial compressive strength of the specimen was measured, and the silica content of the consolidated sand after the measurement of the strength was analyzed by the method for measuring silica content, and the mass of the specimen. Expressed as a ratio of silica content to Further, since the silica of the chemical solution and the silica of the sample sand are eluted from the specimen, the silica content of only the sample sand is also measured to obtain a blank.
(5)結果
一軸圧縮強度の測定結果を表2に示す。また、代表して4週強度について相対密度40%、80%の薬液のシリカ濃度に対する強度の関係を図1に示す。
(5) Results Table 2 shows the measurement results of uniaxial compressive strength. In addition, as a representative, the relationship of the strength with respect to the silica concentration of a chemical solution having a relative density of 40% and 80% for 4 weeks strength is shown in FIG.
薬液のシリカ濃度が高くなれば一軸圧縮強度も高くなり、薬液のシリカ濃度が同じであっても供試体の相対密度が高ければ一軸圧縮強度も高くなる結果となり、シリカ濃度並びに相対密度が一軸圧縮強度に大きく影響することがわかった。 The higher the silica concentration in the chemical solution, the higher the uniaxial compressive strength, and even if the silica concentration in the chemical solution is the same, the higher the relative density of the specimen, the higher the uniaxial compressive strength. It was found that the strength was greatly affected.
次に、強度測定を行った供試体について前記の測定方法によりシリカ含有量を測定し、供試体の質量に対するシリカ含有量の割合を表3、図2に示す。 Next, the silica content of the specimen subjected to strength measurement was measured by the measurement method described above, and the ratio of the silica content to the mass of the specimen is shown in Table 3 and FIG.
試料砂のみのシリカ含有量は0.07 wt%となり、試料砂の可溶性シリカが溶出したものと思われる。図2ではこの値を薬液のシリカ濃度0%としてプロットし、近似線を描いたものである。
薬液のシリカ濃度が高くなれば、それに比例して供試体の質量に対するシリカ含有量の割合も高い値となった。
The silica content of the sample sand alone is 0.07 wt%, and it is thought that the soluble silica of the sample sand was eluted. In FIG. 2, this value is plotted as a silica concentration of the chemical solution of 0%, and an approximate line is drawn.
As the silica concentration of the chemical solution increased, the ratio of the silica content to the mass of the specimen also increased in proportion thereto.
また、相対密度は80%よりも40%の方が供試体の質量に対するシリカ含有量の割合が高くなっている。これは、相対密度を求める式を式3.1に示すが、供試体の相対密度が高いとその間隙が小さくなるためである。 The relative density of 40% is higher than 80%, and the ratio of the silica content to the mass of the specimen is higher. This is because the equation for obtaining the relative density is shown in Equation 3.1 because the gap becomes smaller when the relative density of the specimen is high.
間隙は間隙比や間隙率で表され、土の密度と共に土の力学的特性に大きな影響を及ぼす要因であるが、間隙比が同じであっても砂の種類が異なれば土の力学的特性も違ってしまう。しかし、同じ相対密度で比較すると砂の種類に関係なく土の力学的特性が決まることが多く、広く利用されている。相対密度は砂の現在の締まり具合がその砂の最も密な状態と最も緩い状態の間のどの状態にあるかを示す指標である。従って、シリカの含有量を求める際には供試体試料の相対密度による影響を充分考慮しなければならない。 The gap is expressed by the gap ratio and the porosity, and it is a factor that has a great influence on the soil mechanical properties along with the soil density. It will be different. However, when compared at the same relative density, the mechanical properties of the soil are often determined regardless of the type of sand and are widely used. Relative density is an indicator of how the current tightness of the sand is between the densest state and the loosest state of the sand. Therefore, when determining the silica content, the influence of the relative density of the specimen sample must be fully considered.
ここで、 e:試料の間隙比
ρd:試料の乾燥密度〔g/cm3〕
emax:最小密度試験による試料の間隙比
emin:最大密度試験による試料の間隙比
ρdmax:最大密度試験による試料の乾燥密度〔g/cm3〕
ρdmin:最小密度試験による試料の乾燥密度〔g/cm3〕
Where e: sample gap ratio
ρ d : Dry density of sample [g / cm 3 ]
e max : The gap ratio of the sample by the minimum density test
e min : sample gap ratio by maximum density test
ρ dmax : Dry density of sample by maximum density test [g / cm 3 ]
ρ dmin : Dry density of sample by minimum density test [g / cm 3 ]
実験1
薬液注入による改良地盤中の浸透距離と注入率並びに強度の関係を把握するために、現場採取砂を用いたシリカ濃度6%の溶液型非アルカリ性シリカグラウトの一次元浸透試験を実施し、浸透固結体の一軸圧縮強度を測定して浸透距離と強度の関係を求め、強度測定後の供試体から採取した固結土の注入率を前記のシリカ含有量の測定方法により求めて式1.1から算出し、浸透距離と注入率の関係を求めた。
Experiment 1
In order to understand the relationship between the penetration distance and the injection rate and strength in the improved ground by chemical injection, we conducted a one-dimensional penetration test of a solution-type non-alkaline silica grout with a silica concentration of 6% using on-site collected sand. Measure the uniaxial compressive strength of the knot to determine the relationship between the penetration distance and strength, and calculate the injection rate of solid soil collected from the specimen after strength measurement using the above-mentioned method for measuring the silica content, and calculate from equation 1.1. The relationship between the penetration distance and the injection rate was determined.
(1)薬液
実施例-1と同じ表4示す溶液型非アルカリ性シリカグラウトを用いた。
(1) Chemical solution The same solution type non-alkaline silica grout as shown in Table 4 as in Example-1 was used.
(2)試料砂
現場採取砂
(3)一次元浸透装置
図3に一次元浸透装置を示す。
(2) Sample sand On-site sampling sand (3) One-dimensional infiltration device Figure 3 shows a one-dimensional infiltration device.
(4)一次元浸透試験方法
内径50mm、長さ1.5mの透明アクリル製モールドに相対密度が60%となるように試料砂を充填した。予め水を注入して飽和させてから薬液の注入を行った。薬液の注入はモールド下部より0.03MPaで定圧注入した。薬液注入し始めはモールド上部より水が押し出されメスシリンダーに採取され、その液体のpHは中性を示すが、薬液がモールド上部に達するとメスシリンダーに採取された液体のpHが酸性になることによって、モールド内の水が薬液に置き換わったことを確認し、注入を終了とした。4週間養生し、モールドの端部を50mm除いてから100mmごとに切断し、50mm×100mmの供試体を得た。
(4) One-dimensional penetration test method Sample sand was filled in a transparent acrylic mold having an inner diameter of 50 mm and a length of 1.5 m so that the relative density was 60%. After injecting water in advance to saturate, the chemical solution was injected. The chemical solution was injected at a constant pressure of 0.03 MPa from the bottom of the mold. At the beginning of chemical injection, water is pushed out from the upper part of the mold and collected in the graduated cylinder. The pH of the liquid is neutral, but when the chemical reaches the upper part of the mold, the pH of the liquid collected in the graduated cylinder becomes acidic. Thus, it was confirmed that the water in the mold was replaced with the chemical solution, and the injection was terminated. After curing for 4 weeks and removing the end of the mold by 50 mm, the mold was cut every 100 mm to obtain specimens of 50 mm × 100 mm.
(5)注入率100%の供試体
内径50mm、高さ100mmのモールドを用い、試料砂を用いて相対密度が60%となるように調整して存在する空隙をすべて注入液で充填して注入率100%の供試体を作製した。
(5) Specimen with an injection rate of 100% Using a mold with an inner diameter of 50 mm and a height of 100 mm, adjusting the relative density to 60% using sample sand, filling all existing voids with the injection solution, and injecting A specimen having a rate of 100% was produced.
(6)強度並びにシリカ含有量の測定
(4)一次元浸透試験と(5)注入率100%の供試体作製から得られた供試体の一軸圧縮強度を測定し、強度を測定し終えた固結砂のシリカ含有量を前記のシリカ含有量の測定方法により分析した。
(6) Measurement of strength and silica content (4) One-dimensional penetration test and (5) uniaxial compressive strength of the specimen obtained from the preparation of the specimen with 100% injection rate was measured. The silica content of the set sand was analyzed by the above-described method for measuring the silica content.
(7)結果
注入率100%として作製した供試体並びに一次元浸透試験より得られた供試体の質量〔g〕、体積〔cm3〕を測定し、密度〔g/cm3〕を算出した結果を表5に示す。
(7) Results Results of measurement of the mass [g] and volume [cm 3 ] of the specimen prepared at an injection rate of 100% and the specimen obtained from the one-dimensional penetration test, and calculating the density [g / cm 3 ] Is shown in Table 5.
注入率100%として作製した供試体のシリカ含有量並びに一次元浸透試験による供試体のシリカ含有量を表6に示す。 Table 6 shows the silica content of the specimen prepared at an injection rate of 100% and the silica content of the specimen by the one-dimensional penetration test.
一次元浸透試験による供試体の一軸圧縮強度と注入率を式1.1より求めた結果を表7に示し、浸透距離と注入率並びに強度の関係を図4に示す。更に、注入率と強度の関係を図5に示す。図5には注入率100%として作製した供試体の強度0.35〔MN/m2〕も含む。 Table 7 shows the results obtained by calculating the uniaxial compressive strength and the injection rate of the specimen by the one-dimensional penetration test using Equation 1.1, and FIG. 4 shows the relationship between the penetration distance, the injection rate, and the strength. Furthermore, the relationship between the injection rate and the strength is shown in FIG. FIG. 5 includes the strength 0.35 [MN / m 2 ] of the specimen prepared with an injection rate of 100%.
図4において浸透距離が長くなるほど注入率並びに強度は低下している。これは、薬液がモールド上部に達したのを確認してすぐに注入を終了しており、飽和土に始めに注入された薬液は希釈されているので、土粒子間に充填された薬液量が少なくなったためである。 In FIG. 4, the injection rate and the strength decrease as the penetration distance increases. This is because the injection was finished immediately after confirming that the chemical reached the upper part of the mold, and since the chemical injected first into the saturated soil was diluted, the amount of the chemical filled between the soil particles was reduced. This is because it has decreased.
従って、浸透距離に対する注入率並びに強度の分布は酷似してくる。そこで注入率と強度の関係をプロットしたのが図5であり、注入率と強度の相関係数は0.97と高い相関が得られた。このため化学分析による注入率の測定は、薬液注入による改良範囲並びに改良地盤の固結状況の確認にとどまらず、改良地盤の強度を推定する補助手段としても有効であると考えられる。 Therefore, the injection rate and the intensity distribution with respect to the penetration distance are very similar. Therefore, the relationship between the injection rate and the intensity is plotted in FIG. 5, and the correlation coefficient between the injection rate and the intensity was as high as 0.97. For this reason, the measurement of the injection rate by chemical analysis is considered to be effective as an auxiliary means for estimating the strength of the improved ground as well as confirming the improved range by chemical injection and the consolidation status of the improved ground.
実験2
式1.2により注入率を求める方法を用いて実験1と同様に実験を行って、浸透距離と注入率の関係を求めた。
Experiment 2
The experiment was performed in the same manner as in Experiment 1 using the method for obtaining the injection rate according to Equation 1.2, and the relationship between the penetration distance and the injection rate was obtained.
(1)薬液と実験方法
実験1と同様
(1) Chemical solution and experimental method Same as Experiment 1
(2)シリカ含有量の測定
強度を測定し終えた固結砂並びにこれらの作製に用いた試料砂のシリカ含有量を前記のシリカ含有量の測定方法により分析した。
(2) Measurement of silica content The solidified sand whose strength was measured and the silica content of the sample sand used for the production thereof were analyzed by the method for measuring silica content.
(3)結果
注入率100%として作製した供試体並びに一次元浸透試験より得られた供試体の質量〔g〕、体積〔cm3〕を測定し、密度〔g/cm3〕を算出した結果を表8に示す。また、注入率100%として供試体を作製した際の試料砂の質量〔g〕並びに薬液の質量〔g〕を表9示す。
(3) Results Results of measurement of the mass [g] and volume [cm 3 ] of the specimen prepared with an injection rate of 100% and the specimen obtained from the one-dimensional penetration test, and calculating the density [g / cm 3 ] Is shown in Table 8. Moreover, Table 9 shows the mass [g] of the sample sand and the mass [g] of the chemical solution when the specimen was prepared with an injection rate of 100%.
注入率100%として作製した供試体のシリカ含有量並びに一次元浸透試験による供試体のシリカ含有量、試料砂のシリカ含有量の測定結果を表10に示す。ここで、相対密度60%のときの試料砂の乾燥密度は1.433〔g/cm3〕であった。 Table 10 shows the measurement results of the silica content of the specimen prepared with an injection rate of 100%, the silica content of the specimen by the one-dimensional penetration test, and the silica content of the sample sand. Here, the dry density of the sample sand at a relative density of 60% was 1.433 [g / cm 3 ].
一次元浸透試験による供試体の一軸圧縮強度と注入率を式1.1より求めた結果を表11に示し、浸透距離と注入率並びに強度の関係を図6に示す。更に、注入率と強度の関係を図7に示す。図7には注入率100%として作製した供試体の強度0.32〔MNm2〕も含む。 Table 11 shows the results obtained by calculating the uniaxial compressive strength and the injection rate of the specimen by the one-dimensional penetration test using Equation 1.1, and FIG. 6 shows the relationship between the penetration distance, the injection rate, and the strength. Furthermore, the relationship between the injection rate and the strength is shown in FIG. FIG. 7 includes the strength 0.32 [MNm 2 ] of the specimen prepared with an injection rate of 100%.
実験1と同様に浸透距離に対する注入率並びに強度の分布は酷似しており、注入率と強度の相関係数は0.99と高い相関が得られた。 Similar to Experiment 1, the injection rate and strength distribution with respect to the penetration distance were very similar, and the correlation coefficient between the injection rate and the strength was as high as 0.99.
本発明は溶液型シリカ型グラウトを地盤中に注入後の注入率と改良地盤の固結状況を把握し、さらには改良地盤の固結範囲と固結状況の分布を確認して地盤改良効果の確認を行うものであるから、地盤改良材の注入技術分野での利用可能性が高い。 The present invention grasps the injection rate after injecting the solution type silica grout into the ground and the consolidation status of the improved ground, and further confirms the distribution of the consolidation range and consolidation status of the improved ground, and improves the ground improvement effect. Since it is to be confirmed, the applicability of the ground improvement material in the injection technology field is high.
1 コンプレッサー
2 圧力計
3 注入液
4 注入液バルブ
5 バルブ
6 バルブ
7 アクリル製モールド
8 試料砂
9 排出口
10 メスシリンダー
DESCRIPTION OF SYMBOLS 1 Compressor 2 Pressure gauge 3 Injection liquid 4 Injection liquid valve 5 Valve 6 Valve 7 Acrylic mold 8 Sample sand 9 Outlet 10 Measuring cylinder
Claims (7)
A ground injection method comprising the step of confirming the ground effect of either or both of claims 1 and 2.
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Cited By (1)
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US8851746B2 (en) * | 2012-10-26 | 2014-10-07 | Halliburton Energy Services, Inc. | Geothermal heating and/or cooling system grout testing |
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US8851746B2 (en) * | 2012-10-26 | 2014-10-07 | Halliburton Energy Services, Inc. | Geothermal heating and/or cooling system grout testing |
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