JP2021134524A - Strength estimation method of cement improvement soil - Google Patents

Strength estimation method of cement improvement soil Download PDF

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JP2021134524A
JP2021134524A JP2020030300A JP2020030300A JP2021134524A JP 2021134524 A JP2021134524 A JP 2021134524A JP 2020030300 A JP2020030300 A JP 2020030300A JP 2020030300 A JP2020030300 A JP 2020030300A JP 2021134524 A JP2021134524 A JP 2021134524A
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cement
improved soil
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soil
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JP7366801B2 (en
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弘幸 三枝
Hiroyuki Saegusa
弘幸 三枝
善之 鷲津
Yoshiyuki Washizu
善之 鷲津
友博 森澤
Tomohiro Morisawa
友博 森澤
健二 黒田
Kenji Kuroda
健二 黒田
英幸 浅田
Hideyuki Asada
英幸 浅田
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Toa Corp
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Abstract

To provide a strength estimation method of cement improvement soil capable of simply estimating a strength after the lapse of the specified curing time of a cement improvement soil, at a time before the lapse of the specified curing time.SOLUTION: A water content of a cement improvement soil CS is grasped before the lapse of the specified curing time. Based on a content of a predetermined reference component measured by radiating X-ray R to the cement improvement soil CS by a fluorescent X-ray analyzer 1, a content of a cement-based solidification material in the cement improvement soil CS is grasped. Based on the grasped the water content of the cement improvement soil CS and the grasped content of the cement-based solidification material, a water-cement ratio of the cement improvement soil CS is calculated. Then, based on the calculated water-cement ratio and a relationship data of a strength of the cement improvement soil CS after the lapse of the specified curing time and a water-cement ratio grasped in advance, a strength of the cement improvement soil CS after the lapse of the specified curing time is estimated.SELECTED DRAWING: Figure 2

Description

本発明は、セメント改良土の強度の推定方法に関し、さらに詳しくは、セメント改良土の規定の養生期間後の強度を、規定の養生期間が経過する前の時点で簡便に推定できるセメント改良土の強度の推定方法に関するものである。 The present invention relates to a method for estimating the strength of cement-improved soil, and more specifically, the strength of cement-improved soil after a specified curing period can be easily estimated before the specified curing period elapses. It relates to a method of estimating strength.

軟弱地盤対策や液状化対策等を目的として、地盤中にセメント系固化材を注入して、対象土とセメント系固化材とを混合撹拌することで、対象土をセメント改良土に改良する地盤改良工法が行われている。セメント改良土の規定の養生期間後(例えば、養生7日目や養生28日目)の強度(一軸圧縮強さ)を規定の養生期間が経過する前の時点で推定できれば、注入条件の改善や施工不良の早期発見などの観点から非常に有益である。従来、セメント改良土の強度を推定する方法が種々提案されている(例えば特許文献1参照)。 Ground improvement to improve the target soil to cement-improved soil by injecting a cement-based solidifying material into the ground and mixing and stirring the target soil and the cement-based solidifying material for the purpose of measures against soft ground and liquefaction. The construction method is being carried out. If the strength (uniaxial compressive strength) after the specified curing period of cement-improved soil (for example, 7th day of curing and 28th day of curing) can be estimated before the specified curing period elapses, the injection conditions can be improved. It is very useful from the viewpoint of early detection of construction defects. Conventionally, various methods for estimating the strength of cement-improved soil have been proposed (see, for example, Patent Document 1).

特許文献1に記載の強度判定方法では、低強度ソイルセメントの規定の養生期間後(材齢28日)の強度とセメント水比との関係を、実験等を通じて予め把握しておく。そして、地盤改良工事を実施した後に、強度判定対象の低強度ソイルセメントの未固結試料を採取し、その未固結試料に含まれる水の質量とセメントの質量をそれぞれ測定分析する。そして、予め把握しておいた低強度ソイルセメントの規定の養生期間後の強度およびセメント水比の関係と、前述した測定分析から求めた未固結試料のセメント水比とから低強度ソイルセメントの強度を推定している。 In the strength determination method described in Patent Document 1, the relationship between the strength of low-strength soil cement after a prescribed curing period (age 28 days) and the cement water ratio is grasped in advance through experiments and the like. Then, after the ground improvement work is carried out, an unconsolidated sample of the low-strength soil cement to be determined for strength is collected, and the mass of water and the mass of cement contained in the unconsolidated sample are measured and analyzed, respectively. Then, from the relationship between the strength of the low-strength soil cement after the prescribed curing period and the cement water ratio, which was grasped in advance, and the cement water ratio of the unconsolidated sample obtained from the above-mentioned measurement analysis, the low-strength soil cement The strength is estimated.

特許文献1には、未固結試料のセメント含有量を算出する方法として、水分量を算出した後の未固結試料を所定量の塩酸に溶解させて水酸化ナトリウムで滴定を行う方法や、酸に溶解させた際の溶解熱の算出により求める方法が挙げられている。しかしながら、このような方法では、多くの実験器具や化学薬品を用意する必要があり、多くの作業工数と相応の時間を要する。さらに、化学薬品を扱う緻密な作業を行う必要があるため、施工現場で行う方法としては適していない。それ故、改良のより初期の時点でより簡便にセメント改良土の強度を推定するには改善の余地がある。 Patent Document 1 describes, as a method for calculating the cement content of an unsolidified sample, a method of dissolving an unsolidified sample in a predetermined amount of hydrochloric acid after calculating the water content and titrating with sodium hydroxide. A method of obtaining the heat of dissolution when dissolved in an acid is mentioned. However, such a method requires a lot of laboratory equipment and chemicals to be prepared, and requires a lot of man-hours and a considerable amount of time. Furthermore, it is not suitable as a method to be performed at the construction site because it is necessary to perform precise work dealing with chemicals. Therefore, there is room for improvement in estimating the strength of cement-improved soil more easily at the earlier stage of improvement.

特開2019−105112号公報JP-A-2019-105112

本発明の目的は、セメント改良土の規定の養生期間後の強度を、規定の養生期間が経過する前の時点で簡便に推定できるセメント改良土の強度の推定方法を提供することにある。 An object of the present invention is to provide a method for estimating the strength of cement-improved soil, which can easily estimate the strength of cement-improved soil after a prescribed curing period before the prescribed curing period has elapsed.

上記目的を達成するため本発明のセメント改良土の強度の推定方法は、対象土とセメント系固化材とを混合撹拌することにより形成されるセメント改良土の規定の養生期間後の強度を、予め把握しておいた前記セメント改良土の規定の養生期間後の強度と水セメント比との関係データを用いて推定するセメント改良土の強度の推定方法において、前記セメント改良土の前記規定の養生期間が経過する前に、前記セメント改良土の含水率を把握する含水率把握作業と、前記セメント改良土に蛍光X線分析装置によりX線を照射して前記セメント改良土に含まれる所定の基準成分を測定し、その測定した所定の基準成分の含有率に基づいて前記セメント改良土における前記セメント系固化材の含有率を把握するセメント含有率把握作業とを行い、その把握した前記セメント改良土における前記含水率と前記セメント系固化材の含有率とに基づいて前記セメント改良土の水セメント比を算出し、その算出した水セメント比と予め把握しておいた前記関係データとに基づいて前記規定の養生期間後の前記セメント改良土の強度を推定することを特徴とする。 In order to achieve the above object, the method for estimating the strength of the cement-improved soil of the present invention is to preliminarily determine the strength of the cement-improved soil formed by mixing and stirring the target soil and the cement-based solidifying material after a specified curing period. In the method for estimating the strength of cement-improved soil, which is estimated using the relationship data between the strength after the specified curing period of the cement-improved soil and the water-cement ratio, the specified curing period of the cement-improved soil is used. Before the lapse of time, the work of grasping the water content of the cement-improved soil and the predetermined reference component contained in the cement-improved soil by irradiating the cement-improved soil with X-rays by a fluorescent X-ray analyzer. And based on the measured content of the predetermined reference component, the cement content grasping work for grasping the content of the cement-based solidifying material in the cement-improved soil was performed, and the grasped cement-improved soil was used. The water-cement ratio of the cement-improved soil is calculated based on the water content and the content of the cement-based solidifying material, and the above-mentioned specification is based on the calculated water-cement ratio and the related data grasped in advance. It is characterized in that the strength of the cement-improved soil after the curing period is estimated.

本発明によれば、セメント含有率把握作業において、規定の養生期間が経過する前のセメント改良土に蛍光X線分析装置によりX線を照射してセメント改良土に含まれる所定の基準成分の含有率を測定する。所定の基準成分としては、カルシウムやケイ素、鉄、アルミニウムなどが例示できる。蛍光X線分析装置を用いることで、セメント改良土に含まれる所定の基準成分の含有率を即座に測定できる。セメント系固化材におけるカルシウムの含有率はJIS規格で規定されているので、例えば、蛍光X線分析装置により所定の基準成分としてカルシウムの含有率を測定すれば、その測定したカルシウムの含有率に基づいてセメント改良土におけるセメント系固化材の含有率を把握できる。また、改良の対象となる地盤の土に含まれているケイ素、鉄、アルミニウムのそれぞれの含有率は予め把握することができ、セメント系固化材にはケイ素、鉄、アルミニウムはほとんど含まれていない。そのため、例えば、蛍光X線分析装置により所定の基準成分としてセメント改良土に含まれるケイ素または鉄またはアルミニウムのいずれかの含有率を測定すれば、その測定した含有率に基づいてセメント改良土に含まれる対象土の含有率を把握することができ、それに伴い、セメント改良土におけるセメント系固化材の含有率を把握できる。その把握したセメント系固化材の含有率と、含水率把握作業で把握したセメント改良土における含水率とに基づいてセメント改良土の水セメント比を算出する。そして、その算出した水セメント比と、予め把握しておいたセメント改良土の規定の養生期間後の強度と水セメント比との関係データとを用いることで、規定の養生期間が経過する前の時点であっても、規定の養生期間後のセメント改良土の強度を簡便に推定できる。 According to the present invention, in the cement content grasping work, the cement-improved soil before the specified curing period has elapsed is irradiated with X-rays by a fluorescent X-ray analyzer to contain a predetermined reference component contained in the cement-improved soil. Measure the rate. Examples of the predetermined reference component include calcium, silicon, iron, and aluminum. By using a fluorescent X-ray analyzer, the content of a predetermined reference component contained in the cement-improved soil can be immediately measured. Since the calcium content in the cement-based solidifying material is specified by the JIS standard, for example, if the calcium content is measured as a predetermined reference component by a fluorescent X-ray analyzer, it is based on the measured calcium content. The content of cement-based solidifying material in the cement-improved soil can be grasped. In addition, the content of silicon, iron, and aluminum contained in the soil to be improved can be grasped in advance, and the cement-based solidifying material contains almost no silicon, iron, or aluminum. .. Therefore, for example, if the content of either silicon, iron, or aluminum contained in the cement-improved soil is measured as a predetermined reference component by a fluorescent X-ray analyzer, it is contained in the cement-improved soil based on the measured content. The content of the target soil can be grasped, and the content of the cement-based solidifying material in the cement-improved soil can be grasped accordingly. The water-cement ratio of the cement-improved soil is calculated based on the grasped content of the cement-based solidifying material and the moisture content of the cement-improved soil grasped in the water content grasping work. Then, by using the calculated water-cement ratio and the relationship data between the strength of the cement-improved soil after the specified curing period and the water-cement ratio, which has been grasped in advance, before the specified curing period elapses. Even at the time point, the strength of the cement-improved soil after the specified curing period can be easily estimated.

セメント改良土の規定の養生期間後の強度と水セメント比との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the strength after a specified curing period of cement improved soil, and the water-cement ratio. セメント改良土に蛍光X線分析装置によりX線を照射してセメント改良土に含まれる所定の基準成分の含有率を測定している状況を模式的に例示する説明図である。It is explanatory drawing which typically exemplifies the situation which the cement improved soil is irradiated X-ray by a fluorescent X-ray analyzer, and the content rate of the predetermined reference component contained in the cement improved soil is measured. セメント改良土の試験体を作成したときのカルシウムの含有率の理論値と、土壌養分分析法で測定した試験体のカルシウムの含有率の実測値との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the theoretical value of the calcium content at the time of preparing the test piece of cement improved soil, and the measured value of the calcium content rate of the test piece measured by the soil nutrient analysis method. 土壌養分分析法で測定した試験体のカルシウムの含有率の実測値と、蛍光X線分析装置により測定した試験体のカルシウムの含有率の測定値との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the measured value of the calcium content of a test piece measured by the soil nutrient analysis method, and the measured value of the calcium content of a test piece measured by a fluorescent X-ray analyzer. 蛍光X線分析装置により測定した炉乾燥させた試験体のカルシウムの含有率の測定値と、蛍光X線分析装置により測定した電子レンジを用いて乾燥させた試験体のカルシウムの含有率の測定値との関係を例示するグラフ図である。The measured value of the calcium content of the furnace-dried test piece measured by the fluorescent X-ray analyzer and the measured value of the calcium content of the test piece dried using the microwave oven measured by the fluorescent X-ray analyzer. It is a graph which illustrates the relationship with. セメント改良土の試験体を作成したときのカルシウムの含有率の理論値と、蛍光X線分析装置により測定したカルシウムの含有率の測定値を補正係数で補正した補正値との関係を例示するグラフ図である。A graph exemplifying the relationship between the theoretical value of the calcium content when a test piece of cement-improved soil was prepared and the correction value obtained by correcting the measured value of the calcium content measured by a fluorescent X-ray analyzer with a correction coefficient. It is a figure. セメント改良土の試験体を作成したときのケイ素の含有率の理論値と、蛍光X線分析装置により測定した試験体のケイ素の含有率の測定値との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the theoretical value of the silicon content at the time of making the test piece of cement improved soil, and the measured value of the silicon content of the test piece measured by a fluorescent X-ray analyzer. 蛍光X線分析装置により測定したケイ素の含有率の測定値を補正係数で補正した補正値と、試験体のセメント水比との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the correction value which corrected the measured value of the silicon content measured by the fluorescent X-ray analyzer by the correction coefficient, and the cement water ratio of the test piece. セメント改良土の試験体を作成したときの鉄の含有率の理論値と、蛍光X線分析装置により測定した試験体の鉄の含有率の測定値との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the theoretical value of the iron content at the time of making the test piece of cement improved soil, and the measured value of the iron content rate of the test piece measured by a fluorescent X-ray analyzer. 蛍光X線分析装置により測定した鉄の含有率の測定値を補正係数で補正した補正値と、試験体のセメント水比との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the correction value which corrected the measured value of the iron content measured by the fluorescent X-ray analyzer with the correction coefficient, and the cement water ratio of the test piece. セメント改良土の試験体を作成したときのアルミニウムの含有率の理論値と、蛍光X線分析装置により測定した試験体のアルミニウムの含有率の測定値との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the theoretical value of the aluminum content at the time of making the test piece of cement improved soil, and the measured value of the aluminum content rate of the test piece measured by a fluorescent X-ray analyzer. 蛍光X線分析装置により測定したアルミニウムの含有率の測定値を補正係数で補正した補正値と、試験体のセメント水比との関係を例示するグラフ図である。It is a graph which illustrates the relationship between the correction value which corrected the measured value of the aluminum content measured by the fluorescent X-ray analyzer with the correction coefficient, and the cement water ratio of the test piece.

以下、本発明のセメント改良土の強度の推定方法を図に示した実施形態に基づいて説明する。 Hereinafter, the method for estimating the strength of the cement-improved soil of the present invention will be described based on the embodiment shown in the figure.

本発明は、対象土とセメント系固化材とを混合撹拌することにより形成されるセメント改良土の規定の養生期間後の強度を、セメント改良土の規定の養生期間が経過する前の時点、より好ましくはセメント改良土の改良初期に推定する。セメント系固化材は、母材となるセメントに各種の添加物を混合した固化材である。セメント処理土の規定の養生期間後の強度とは、例えば、地盤改良工法において対象土に対するセメント系固化材の添加量(混合比率)を決定する際の基準となるセメント改良土の養生7日目や養生28日目、養生91日目等の一軸圧縮強さである。セメント改良土の規定の養生期間が経過する前の時点とは、例えば、セメント改良土の養生7日目の強度を推定する場合には養生7日目以前、即ち、対象土とセメント系固化材とを混合撹拌してから養生0〜6日目である。同様に、例えば、セメント改良土の養生28日目の強度を推定する場合には養生28日目以前、セメント改良土の養生91日目の強度を推定する場合には養生91日目以前である。セメント改良土の改良初期とは、セメント改良土が十分に硬化する前の期間であり、対象土にセメント系固化材を混合撹拌してから3日以内(養生0〜3日目)である。 In the present invention, the strength of the cement-improved soil formed by mixing and stirring the target soil and the cement-based solidifying material after the specified curing period is increased from the time before the specified curing period of the cement-improved soil elapses. It is preferably estimated at the initial stage of improvement of cement-improved soil. The cement-based solidifying material is a solidifying material in which various additives are mixed with cement as a base material. The strength after the specified curing period of cement-treated soil is, for example, the 7th day of curing of cement-improved soil, which is a standard for determining the amount (mixing ratio) of cement-based solidifying material added to the target soil in the ground improvement method. It is the uniaxial compressive strength such as the 28th day of curing and the 91st day of curing. The time before the specified curing period of the cement-improved soil has passed is, for example, before the 7th day of curing when estimating the strength of the cement-improved soil on the 7th day of curing, that is, the target soil and the cement-based solidifying material. It is the 0th to 6th days of curing after mixing and stirring. Similarly, for example, when estimating the strength of the cement-improved soil on the 28th day of curing, it is before the 28th day of curing, and when estimating the strength of the cement-improved soil on the 91st day of curing, it is before the 91st day of curing. .. The initial stage of improvement of the cement-improved soil is a period before the cement-improved soil is sufficiently hardened, and is within 3 days (curing 0 to 3 days) after mixing and stirring the cement-based solidifying material in the target soil.

本発明の推定方法では大きく分けて、関係データ取得作業、含水率把握作業、セメント含有率把握作業、および強度推定作業の4つの作業を行う。以下では、地盤改良工事を行う施工現場において、地盤中に形成したセメント改良土の規定の養生期間後の強度を推定する場合を例示して、各作業の詳細を説明する。 The estimation method of the present invention is roughly divided into four operations: related data acquisition work, water content grasping work, cement content grasping work, and strength estimation work. In the following, the details of each work will be described by exemplifying the case of estimating the strength of the cement-improved soil formed in the ground after the prescribed curing period at the construction site where the ground improvement work is carried out.

関係データ取得作業は、含水率把握作業、セメント含有率把握作業、および強度推定作業を行う以前に予め行っておく作業である。図1に例示するように、関係データ把握作業では、セメント改良土の規定の養生期間後の強度と水セメント比との関係データを取得しておく。図1に示すように、セメント改良土の規定の養生期間後の強度とセメント改良土の水セメント比は相関関係を有している。 The related data acquisition work is a work to be performed in advance before performing the water content grasping work, the cement content grasping work, and the strength estimation work. As illustrated in FIG. 1, in the relational data grasping work, the relational data between the strength after the prescribed curing period of the cement-improved soil and the water-cement ratio is acquired. As shown in FIG. 1, there is a correlation between the strength of the cement-improved soil after the specified curing period and the water-cement ratio of the cement-improved soil.

セメント改良土の規定の養生期間後の強度と水セメント比との関係データは、例えば、水セメント比を異ならせたセメント改良土の試験体を複数作成し、規定の養生期間経過したそれぞれの試験体に対して、一軸圧縮試験(JIS A 1216:土の一軸圧縮試験方法)を行うことで取得することができる。過去に行った工事等でセメント改良土の規定の養生期間後の強度と水セメント比との関係データを保有している場合には、その関係データを用いることで、関係データ取得作業を省略することもできる。 For the data on the relationship between the strength of cement-improved soil after the specified curing period and the water-cement ratio, for example, multiple test specimens of cement-improved soil with different water-cement ratios were prepared, and each test after the specified curing period had passed. It can be obtained by performing a uniaxial compression test (JIS A 1216: soil uniaxial compression test method) on a body. If the relationship data between the strength after the specified curing period of the cement-improved soil and the water-cement ratio is retained in the past construction work, etc., the relationship data acquisition work can be omitted by using the relationship data. You can also do it.

地盤改良工事を行う施工現場では、地盤中にセメント系固化材を注入して、地盤中の対象土とセメント系固化材とを混合撹拌することにより地盤中の対象土をセメント改良土に改良する。そして、地盤中のセメント改良土の規定の養生期間が経過する前、より好ましくはセメント改良土の改良初期に、地盤中からセメント改良土を採取する。具体的には例えば、掘削ロッドに取り付けた試料採取器を使用して、地盤中のセメント改良土を採取する。 At the construction site where ground improvement work is carried out, the target soil in the ground is improved to cement-improved soil by injecting a cement-based solidifying material into the ground and mixing and stirring the target soil in the ground and the cement-based solidifying material. .. Then, the cement-improved soil is collected from the ground before the prescribed curing period of the cement-improved soil in the ground elapses, more preferably at the initial stage of the improvement of the cement-improved soil. Specifically, for example, a sampling device attached to an excavation rod is used to collect cement-improved soil in the ground.

次いで、含水率把握作業とセメント含有率把握作業を行う。含水率把握作業では、セメント改良土の含水率を把握する。セメント改良土の含水率は、電子レンジを用いることで、簡易に短時間で把握できる。具体的には、セメント改良土の試料の重量を測定した後に、その試料を電子レンジを用いて乾燥させる。そして、試料の乾燥させる前の重量と乾燥させた後の重量との差分に基づいてセメント改良土の含水率を算出する。セメント改良土の含水率は、例えば、乾燥炉を用いた含水比試験(JIS 1203:土の含水比試験方法)等の他の方法で求めることもできる。 Next, the water content grasping work and the cement content grasping work are performed. In the water content grasping work, the water content of the cement-improved soil is grasped. The water content of the cement-improved soil can be easily grasped in a short time by using a microwave oven. Specifically, after weighing the sample of the cement-improved soil, the sample is dried using a microwave oven. Then, the water content of the cement-improved soil is calculated based on the difference between the weight of the sample before drying and the weight after drying. The water content of the cement-improved soil can also be determined by another method such as a water content ratio test using a drying furnace (JIS 1203: soil water content ratio test method).

図2に例示するように、セメント含有率把握作業では、セメント改良土CSに蛍光X線分析装置1によりX線Rを照射してセメント改良土CSに含まれる所定の基準成分の含有率を測定する。所定の基準成分としては、例えば、カルシウム(Ca)やケイ素(Si)、鉄(Fe)、アルミニウム(Al)などが例示できる。そして、その測定した所定の基準成分の含有率に基づいてセメント改良土CSにおけるセメント系固化材の含有率を把握する。 As illustrated in FIG. 2, in the cement content grasping work, the cement-improved soil CS is irradiated with X-ray R by a fluorescent X-ray analyzer 1 to measure the content of a predetermined reference component contained in the cement-improved soil CS. do. Examples of the predetermined reference component include calcium (Ca), silicon (Si), iron (Fe), and aluminum (Al). Then, the content rate of the cement-based solidifying material in the cement-improved soil CS is grasped based on the measured content rate of the predetermined reference component.

セメント系固化材におけるカルシウムの含有率はJIS規格で規定されている。そのため、セメント改良土CSに含まれるカルシウムの含有率を測定することで、セメント改良土CSにおけるセメント系固化材の含有率を把握することが可能である。また、土に含まれているケイ素、鉄、アルミニウムのそれぞれの含有率は公知の全岩分析などで地盤改良工事を行う前に予め把握することができ、セメント系固化材にはケイ素、鉄、アルミニウムはほとんど含まれていない。そのため、セメント改良土CSに含まれるケイ素または鉄またはアルミニウムのいずれかの含有率を測定することで、セメント改良土CSに含まれる対象土の含有率を把握することができ、それに伴い、セメント改良土CSにおけるセメント系固化材の含有率を把握できる。 The calcium content in cement-based solidifying materials is specified by JIS standards. Therefore, by measuring the content of calcium contained in the cement-improved soil CS, it is possible to grasp the content of the cement-based solidifying material in the cement-improved soil CS. In addition, the content of silicon, iron, and aluminum contained in the soil can be grasped in advance by known whole rock analysis before ground improvement work, and silicon, iron, and cement-based solidifying materials can be used as cement-based solidifying materials. It contains almost no aluminum. Therefore, by measuring the content of either silicon, iron, or aluminum contained in the cement-improved soil CS, the content of the target soil contained in the cement-improved soil CS can be grasped, and the cement improvement can be performed accordingly. The content of cement-based solidifying material in soil CS can be grasped.

蛍光X線分析装置1は、一般的に金属製品の品質管理や金属汚染の土壌解析で使用されるが、本発明では、蛍光X線分析装置1をセメント改良土CSに含まれる所定の基準成分の含有率の測定に転用する。蛍光X線分析装置1による蛍光X線分析では、物質に一定以上のエネルギーをもつX線Rを照射することによって、その物質を構成する原子の内殻電子が励起されて生じた空孔に、外殻の電子が遷移する際に放出される特性X線を検出する。特性X線の波長(エネルギー)は内殻と外殻のエネルギー差に対応し、この値は元素ごとに固有であることを利用して元素の同定を行い、その強度からそれぞれの元素の含有量を検出する。 The fluorescent X-ray analyzer 1 is generally used for quality control of metal products and soil analysis of metal contamination. In the present invention, the fluorescent X-ray analyzer 1 is used as a predetermined reference component contained in cement-improved soil CS. It is diverted to the measurement of the content rate of. In the fluorescent X-ray analysis by the fluorescent X-ray analyzer 1, when the substance is irradiated with X-ray R having a certain energy or more, the inner shell electrons of the atoms constituting the substance are excited to form the pores. Detects characteristic X-rays emitted when electrons in the outer shell transition. The wavelength (energy) of the characteristic X-ray corresponds to the energy difference between the inner shell and the outer shell, and the element is identified by utilizing the fact that this value is unique to each element, and the content of each element is determined from its intensity. Is detected.

図2に例示するように、ハンドヘルド型の蛍光X線分析装置1を用いる場合には、蛍光X線分析装置1のX線Rの照射部を容器に入れたセメント改良土CSに向けた状態にし、蛍光X線分析装置1の持ち手に設けられているトリガー2を引くだけで、数十秒後には蛍光X線分析装置1の後部に設けられている表示画面3にセメント改良土CSに含まれる所定の基準成分の含有量が表示される。このように、蛍光X線分析装置1を使用することで、少ない作業工数で即座にセメント改良土CSに含まれる所定の基準成分の含有率を測定できる。ハンドヘルド型の蛍光X線分析装置1に限らず、例えば、据え付け型の蛍光X線分析装置1を用いる場合にも少ない作業工数で即座にセメント改良土CSに含まれる所定の基準成分の含有量を測定できる。 As illustrated in FIG. 2, when the handheld type fluorescent X-ray analyzer 1 is used, the X-ray R irradiation part of the fluorescent X-ray analyzer 1 is oriented toward the cement-improved soil CS in the container. , Just pull the trigger 2 provided on the handle of the fluorescent X-ray analyzer 1, and after several tens of seconds, the display screen 3 provided at the rear of the fluorescent X-ray analyzer 1 will be included in the cement-improved soil CS. The content of a given reference component is displayed. As described above, by using the fluorescent X-ray analyzer 1, the content rate of a predetermined reference component contained in the cement-improved soil CS can be immediately measured with a small number of man-hours. Not limited to the handheld type fluorescent X-ray analyzer 1, for example, even when the stationary fluorescent X-ray analyzer 1 is used, the content of a predetermined reference component contained in the cement-improved soil CS can be immediately determined with a small number of man-hours. Can be measured.

本発明者らは、所定の基準成分としてカルシウムを測定する場合の蛍光X線分析装置1のキャリブレーションを行うために、セメント系固化材(カルシウム)の含有率を異ならせて作成した複数種類のセメント改良土CSの試験体に対して、蛍光X線分析装置1によるカルシウムの含有率の測定を行った。そして、蛍光X線分析装置1によるカルシウムの含有率の測定値と、試験体を作成したときのカルシウムの含有率の理論値(実際に配合調整したカルシウムの含有率の値)と比較を行った。 The present inventors have created a plurality of types having different contents of the cement-based solidifying material (calcium) in order to calibrate the fluorescent X-ray analyzer 1 when measuring calcium as a predetermined reference component. The calcium content of the specimen of cement-improved soil CS was measured by the fluorescent X-ray analyzer 1. Then, the measured value of the calcium content by the fluorescent X-ray analyzer 1 was compared with the theoretical value of the calcium content when the test piece was prepared (the value of the calcium content actually adjusted). ..

図3の横軸は、セメント改良土CSの試験体を作成したときのカルシウムの含有率の理論値を示し、縦軸は土壌養分分析法で測定した試験体のカルシウムの含有率の実測値を示している。図3に示すように、理論値と土壌養分分析法の実測値はほぼ一致した。土壌養分分析法は、土壌に含まれる化学成分を詳細に分析する公知の分析法である。 The horizontal axis of FIG. 3 shows the theoretical value of the calcium content when the test piece of cement-improved soil CS was prepared, and the vertical axis shows the measured value of the calcium content of the test piece measured by the soil nutrient analysis method. Shown. As shown in FIG. 3, the theoretical value and the measured value of the soil nutrient analysis method were almost the same. The soil nutrient analysis method is a known analytical method for analyzing the chemical components contained in soil in detail.

図4の横軸は土壌養分分析法で測定した試験体のカルシウムの含有率の実測値を示し、縦軸は蛍光X線分析装置1で測定した試験体のカルシウムの含有率の測定値を示している。図4に示すように、蛍光X線分析装置1によるカルシウムの含有率の測定値は、土壌養分分析法によるカルシウムの含有率の実測値に補正係数Aを掛けた値に概ね一致した。このことから、蛍光X線分析装置1によって測定したカルシウムの含有率の測定値に、補正係数Aを掛けて補正した補正値を算出することで、セメント改良土CSのカルシウムの含有率を精度よく把握できることが分かる。本発明者らが使用した蛍光X線分析装置1の補正係数Aは1.3であった。 The horizontal axis of FIG. 4 shows the measured value of the calcium content of the test piece measured by the soil nutrient analysis method, and the vertical axis shows the measured value of the calcium content of the test piece measured by the fluorescent X-ray analyzer 1. ing. As shown in FIG. 4, the measured value of the calcium content by the fluorescent X-ray analyzer 1 generally coincided with the value obtained by multiplying the measured value of the calcium content by the soil nutrient analysis method by the correction coefficient A. From this, by multiplying the measured value of the calcium content measured by the fluorescent X-ray analyzer 1 by the correction coefficient A to calculate the corrected value, the calcium content of the cement-improved soil CS can be accurately obtained. You can see that you can grasp it. The correction coefficient A of the fluorescent X-ray analyzer 1 used by the present inventors was 1.3.

図5の横軸は蛍光X線分析装置1により測定した炉乾燥させた試験体のカルシウムの含有率の測定値を示し、縦軸は蛍光X線分析装置1により測定した電子レンジを用いて乾燥させた試験体のカルシウムの含有率の測定値を示している。図5に示すように、セメント改良土CSを電子レンジを用いて乾燥させた場合にも、炉で乾燥させた場合とカルシウムの含有率の測定値はほとんど変わらないことが確認できた。このことから、電子レンジで乾燥させたセメント改良土CSに対して蛍光X線分析装置1でカルシウムの含有率を測定する場合にも、セメント改良土CSのカルシウムの含有率を精度よく把握できることが分かる。 The horizontal axis of FIG. 5 shows the measured value of the calcium content of the specimen dried in the furnace measured by the fluorescent X-ray analyzer 1, and the vertical axis shows the measured value of the calcium content of the test piece dried by the fluorescent X-ray analyzer 1. The measured value of the calcium content of the tested body is shown. As shown in FIG. 5, it was confirmed that even when the cement-improved soil CS was dried using a microwave oven, the measured values of the calcium content were almost the same as those when the cement-improved soil CS was dried in a microwave oven. From this, it is possible to accurately grasp the calcium content of the cement-improved soil CS even when the calcium content of the cement-improved soil CS dried in a microwave oven is measured by the fluorescent X-ray analyzer 1. I understand.

図6の横軸はセメント改良土CSの試験体を作成したときのカルシウムの含有率の理論値を示し、縦軸は蛍光X線分析装置1で測定した試験体のカルシウムの含有率の測定値を補正係数Aで補正した補正値を示している。図6に示すように、蛍光X線分析装置1の測定値を補正係数Aで補正した補正値は、理論値にほぼ一致した。このことから、蛍光X線分析装置1によるカルシウムの含有率の測定値に、補正係数Aを掛けて補正した補正値を算出することで、セメント改良土CSのカルシウムの含有率を精度よく把握できることが分かる。 The horizontal axis of FIG. 6 shows the theoretical value of the calcium content when the test piece of the cement-improved soil CS was prepared, and the vertical axis shows the measured value of the calcium content of the test piece measured by the fluorescent X-ray analyzer 1. Is corrected by the correction coefficient A. As shown in FIG. 6, the correction value obtained by correcting the measured value of the fluorescent X-ray analyzer 1 with the correction coefficient A substantially coincided with the theoretical value. From this, it is possible to accurately grasp the calcium content of the cement-improved soil CS by calculating the corrected value by multiplying the measured value of the calcium content by the fluorescent X-ray analyzer 1 by the correction coefficient A. I understand.

つまり、蛍光X線分析装置1に対応する補正係数Aを予め把握しておけば、施工現場では蛍光X線分析装置1で測定したセメント改良土CSのカルシウムの含有率の測定値に補正係数Aを掛けて補正値を算出するだけで、セメント改良土CSのカルシウムの含有率を精度よく把握できる。そして、その把握したセメント改良土CSのカルシウムの含有率と、JIS規格で規定されているセメント系固化材におけるカルシウムの含有率とに基づいて、セメント改良土CSにおけるセメント系固化材の含有率を算出できる。 That is, if the correction coefficient A corresponding to the fluorescent X-ray analyzer 1 is known in advance, the correction coefficient A is added to the measured value of the calcium content of the cement-improved soil CS measured by the fluorescent X-ray analyzer 1 at the construction site. The calcium content of the cement-improved soil CS can be accurately grasped simply by multiplying by and calculating the correction value. Then, based on the calcium content of the cement-improved soil CS and the calcium content of the cement-based solidifying material specified in the JIS standard, the content of the cement-based solidifying material in the cement-based solidifying material is determined. Can be calculated.

本発明者らは、所定の基準成分としてケイ素または鉄またはアルミニウムのいずれかを測定する場合についても同様の試験を行い、蛍光X線分析装置1によるケイ素、鉄、アルミニウムのそれぞれの含有率の測定値と、試験体を作成したときのケイ素、鉄、アルミニウムのそれぞれの含有率の理論値との比較を行った。前述した理論値は試験体の作成に使用した土に含まれるケイ素、鉄、アルミニウムの含有率を全岩分析により実測することで求めることができる。全岩分析は、土壌に含まれる元素の割合を詳細に分析する公知の分析方法である。 The present inventors perform the same test when measuring either silicon, iron, or aluminum as a predetermined reference component, and measure the content of silicon, iron, and aluminum by the fluorescent X-ray analyzer 1. The values were compared with the theoretical values of the respective contents of silicon, iron, and aluminum when the test piece was prepared. The above-mentioned theoretical value can be obtained by actually measuring the content of silicon, iron, and aluminum contained in the soil used for preparing the test piece by whole rock analysis. Whole rock analysis is a known analytical method that analyzes the proportion of elements contained in soil in detail.

図7の横軸は、蛍光X線分析装置1で測定した試験体のケイ素の含有率の測定値を示し、縦軸は試験体を作成したときのケイ素の含有率の理論値を示している。図7に示すように、蛍光X線分析装置1によるケイ素の含有率の測定値は、ケイ素の含有率の理論値に補正係数Bを掛けた値に概ね一致する。このことから、蛍光X線分析装置1によって測定したケイ素の含有率の測定値に、補正係数Bを掛けて補正した補正値を算出することで、セメント改良土CSのケイ素の含有率を精度よく把握できることが分かる。 The horizontal axis of FIG. 7 shows the measured value of the silicon content of the test piece measured by the fluorescent X-ray analyzer 1, and the vertical axis shows the theoretical value of the silicon content of the test piece when the test piece was prepared. .. As shown in FIG. 7, the measured value of the silicon content by the fluorescent X-ray analyzer 1 generally matches the value obtained by multiplying the theoretical value of the silicon content by the correction coefficient B. From this, by multiplying the measured value of the silicon content measured by the fluorescent X-ray analyzer 1 by the correction coefficient B to calculate the corrected value, the silicon content of the cement-improved soil CS can be accurately obtained. You can see that you can grasp it.

図8の横軸は試験体のセメント水比を示し、縦軸は蛍光X線分析装置1によって測定したケイ素の含有率の測定値を補正係数Bで補正した補正値を示している。図8に示すように、前述した補正値とセメント水比は相関関係を有している。このことから、蛍光X線分析装置1によって測定したセメント改良土CSにおけるケイ素の含有率に基づいて、セメント改良土CSのセメント水比を精度よく把握できることが分かる。セメント水比(C/W)は、水セメント比(W/C)の逆数であるので、セメント改良土CSのセメント水比が把握できれば水セメント比も把握できる。 The horizontal axis of FIG. 8 shows the cement water ratio of the test piece, and the vertical axis shows the correction value obtained by correcting the measured value of the silicon content measured by the fluorescent X-ray analyzer 1 with the correction coefficient B. As shown in FIG. 8, the above-mentioned correction value and the cement water ratio have a correlation. From this, it can be seen that the cement water ratio of the cement-improved soil CS can be accurately grasped based on the silicon content in the cement-improved soil CS measured by the fluorescent X-ray analyzer 1. Since the cement-water ratio (C / W) is the reciprocal of the water-cement ratio (W / C), if the cement-water ratio of the cement-improved soil CS can be grasped, the water-cement ratio can also be grasped.

図9、図11に示すように、所定の基準成分を鉄、アルミニウムとした場合についても同様に、蛍光X線分析装置1による鉄、アルミニウムのそれぞれの含有率の測定値は、鉄、アルミニウムの含有率の理論値にそれぞれ補正係数C、Dを掛けた値に概ね一致した。また、図10、図12に示すように、蛍光X線分析装置1によって測定した鉄、アルミニウムのそれぞれの含有率の測定値をそれぞれ補正係数C、Dで補正した補正値と、試験体のセメント水比はそれぞれ相関関係を有している。このことから、所定の基準成分を鉄、アルミニウムとした場合についても同様に、蛍光X線分析装置1によって測定したセメント改良土CSにおける鉄、アルミニウムの含有率に基づいて、セメント改良土CSの水セメント比を精度よく把握できることが分かる。 As shown in FIGS. 9 and 11, similarly, when the predetermined reference components are iron and aluminum, the measured values of the contents of iron and aluminum by the fluorescent X-ray analyzer 1 are those of iron and aluminum. It was almost the same as the value obtained by multiplying the theoretical value of the content rate by the correction coefficients C and D, respectively. Further, as shown in FIGS. 10 and 12, the correction values obtained by correcting the measured values of the respective contents of iron and aluminum measured by the fluorescent X-ray analyzer 1 with the correction coefficients C and D, respectively, and the cement of the test piece. The water ratios have a correlation with each other. From this, similarly, even when the predetermined reference components are iron and aluminum, the water in the cement-improved soil CS is based on the iron and aluminum contents in the cement-improved soil CS measured by the fluorescent X-ray analyzer 1. It can be seen that the cement ratio can be grasped accurately.

前述した補正係数(A〜D)は所定の基準成分として設定する成分毎にそれぞれ異なる。また、蛍光X線分析装置1の製造元や個体差によっても異なる。そのため、所定の基準成分として設定する成分と使用する蛍光X線分析装置1の条件毎にそれぞれ補正係数を予め把握しておくとよい。 The above-mentioned correction coefficients (A to D) are different for each component set as a predetermined reference component. It also depends on the manufacturer of the fluorescent X-ray analyzer 1 and individual differences. Therefore, it is preferable to grasp the correction coefficient in advance for each of the component set as a predetermined reference component and the condition of the fluorescent X-ray analyzer 1 to be used.

次いで、強度推定作業では、含水率把握作業で把握したセメント改良土CSにおける含水率と、セメント含有率把握作業で把握したセメント改良土CSにおけるセメント系固化材の含有率とに基づいてセメント改良土CSの水セメント比を算出する。そして、その算出したセメント改良土CSの水セメント比と、関係データ取得作業で予め把握しておいたセメント改良土CSの規定の養生期間後の強度と水セメント比との関係データとに基づいて、規定の養生期間後のセメント改良土CSの強度を推定する。 Next, in the strength estimation work, the cement-improved soil is based on the water content in the cement-improved soil CS grasped in the water content grasping work and the cement-based solidifying material content in the cement-improved soil CS grasped in the cement content grasping work. Calculate the water-cement ratio of CS. Then, based on the calculated water-cement ratio of the cement-improved soil CS and the relationship data between the strength after the prescribed curing period of the cement-improved soil CS and the water-cement ratio, which was grasped in advance in the related data acquisition work. , Estimate the strength of cement-improved soil CS after the prescribed curing period.

このように、本発明は、セメント改良土CSに含まれるカルシウムやケイ素などの所定の基準成分の含有率からセメント改良土CSにおけるセメント系固化材の含有率を把握することが可能であることに着目し、かつ、所定の基準成分の含有率を測定するために蛍光X線分析装置1を用いることが大きな特徴の一つである。蛍光X線分析装置1は、一般的に金属製品の品質管理や金属汚染の土壌解析で使用されていて扱い易い装置である。そのため、セメント改良土CSにおけるセメント系固化材の含有率を少ない作業工数で簡易に把握することが可能となる。本発明では、施工現場に多くの実験器具や化学薬品を用意する必要がなく、化学薬品を取り扱う緻密な作業も必要としない。そのため、セメント改良土CSの養生期間が経過する前においてセメント改良土CSの規定の養生期間後の強度を従来の方法よりもより簡便に推定できる。本発明では、セメント改良土CSを採取してから、10分程度の短時間でセメント改良土CSの規定の養生期間後の強度を推定できるので、当業者にとって非常に有益である。 As described above, the present invention makes it possible to grasp the content of the cement-based solidifying material in the cement-improved soil CS from the content of predetermined reference components such as calcium and silicon contained in the cement-improved soil CS. One of the major features is that the fluorescent X-ray analyzer 1 is used to pay attention and measure the content of a predetermined reference component. The fluorescent X-ray analyzer 1 is an easy-to-use device that is generally used for quality control of metal products and soil analysis of metal contamination. Therefore, it is possible to easily grasp the content of the cement-based solidifying material in the cement-improved soil CS with a small number of man-hours. In the present invention, it is not necessary to prepare many laboratory instruments and chemicals at the construction site, and it is not necessary to carry out detailed work for handling the chemicals. Therefore, before the curing period of the cement-improved soil CS elapses, the strength after the prescribed curing period of the cement-improved soil CS can be estimated more easily than the conventional method. In the present invention, the strength of the cement-improved soil CS after the specified curing period can be estimated in a short time of about 10 minutes after the cement-improved soil CS is collected, which is very beneficial to those skilled in the art.

含水率把握作業とセメント含有率把握作業は、それぞれセメント改良土CSの別々の試料を用いて並行して行うことが可能である。特許文献1に記載の発明では、低強度ソイルセメントの未固結試料に含まれる水分量を測定した後に、その水分量を算出した後の未固結試料を用いてセメント含有量を算出する構成にしているが、本発明では、含水率把握作業とセメント含有率把握作業とを並行して行うことで、セメント改良土CSの水セメント比をより短い時間で把握することが可能である。 The water content grasping work and the cement content grasping work can be performed in parallel using separate samples of the cement-improved soil CS. In the invention described in Patent Document 1, the cement content is calculated using the unconsolidated sample after measuring the water content of the low-strength soil cement in the unconsolidated sample and then calculating the water content. However, in the present invention, it is possible to grasp the water-cement ratio of the cement-improved soil CS in a shorter time by performing the water content grasping work and the cement content grasping work in parallel.

本発明では、含水率把握作業で乾燥させたセメント改良土CSの試料を使用してセメント含有率把握作業を行うこともできる。含水率把握作業とセメント含有率把握作業とで同じ試料を用いると、より少ない試料でセメント改良土CSの規定の養生期間後の強度を推定できる。 In the present invention, the cement content grasping work can also be performed using a sample of cement-improved soil CS dried in the water content grasping work. If the same sample is used for the water content grasping work and the cement content grasping work, the strength of the cement-improved soil CS after the specified curing period can be estimated with a smaller number of samples.

セメント改良土CSに含まれるカルシウムの含有量に比べると非常に少ないが、セメント系固化材による改良を行う前の対象土に元々少量のカルシウムが含まれている場合がある。また、同じ地盤であれば土に含まれているケイ素、鉄、アルミニウムの含有率はそれぞれ概ね同じであるが、厳密には対象土を採取した位置によって微小なバラツキがある。そのため、セメント系固化材を混合撹拌する前の対象土に含まれている所定の基準成分の含有率を予め把握しておく。そして、その対象土に元々含まれている所定の基準成分の含有率と、蛍光X線分析装置1によって測定したセメント改良土CSに含まれる所定の基準成分の含有率とに基づいて、セメント改良土CSにおけるセメント系固化材の含有率を把握するとよい。 Although it is very small compared to the calcium content in the cement-improved soil CS, the target soil before the improvement with the cement-based solidifying material may originally contain a small amount of calcium. Further, if the ground is the same, the contents of silicon, iron, and aluminum contained in the soil are almost the same, but strictly speaking, there are slight variations depending on the position where the target soil is collected. Therefore, the content rate of the predetermined reference component contained in the target soil before mixing and stirring the cement-based solidifying material is grasped in advance. Then, based on the content of the predetermined reference component originally contained in the target soil and the content of the predetermined reference component contained in the cement-improved soil CS measured by the fluorescent X-ray analyzer 1, the cement is improved. It is advisable to grasp the content of cement-based solidifying material in soil CS.

対象土に元々含まれている所定の基準成分の含有率は、セメント系固化材による改良を行う前の対象土に対して蛍光X線分析装置1による所定の基準成分の含有率の測定作業を行うことで簡易に把握できる。対象土に元々含まれている所定の基準成分の含有率を考慮することでセメント系固化材の含有率をより精度よく把握することができ、これに伴い、セメント改良土CSの規定の養生期間後の強度を精度よく推定するにはより有利になる。 The content of the predetermined reference component originally contained in the target soil is determined by measuring the content of the predetermined reference component with the fluorescent X-ray analyzer 1 for the target soil before the improvement with the cement-based solidifying material. You can easily grasp it by doing it. By considering the content of the predetermined reference component originally contained in the target soil, the content of the cement-based solidifying material can be grasped more accurately, and along with this, the prescribed curing period of the cement-improved soil CS It is more advantageous to estimate the later strength accurately.

上述したように、セメント含有率把握作業を行う以前に、所定の基準成分の含有率を異ならせて作成した複数種類のセメント改良土CSの試験体に対して、蛍光X線分析装置1による所定の基準成分の含有率の測定を行う。そして、蛍光X線分析装置1による所定の基準成分の含有率の測定値と、試験体を作成したときの所定の基準成分の含有率の理論値に基づいて、蛍光X線分析装置1による測定値を理論値に近づける補正係数を予め把握しておくことが好ましい。そして、セメント含有率把握作業では蛍光X線分析装置1による測定値を補正係数で補正した補正値に基づいて、セメント改良土CSにおけるセメント系固化材の含有率を把握するとよい。使用する蛍光X線分析装置1の補正係数を予め把握しておくことで、セメント改良土CSにおけるセメント系固化材の含有率をより精度よく把握することができ、これに伴い、セメント改良土CSの規定の養生期間後の強度を精度よく推定するにはより有利になる。 As described above, the fluorescent X-ray analyzer 1 is used to determine the test specimens of a plurality of types of cement-improved soil CS prepared with different contents of predetermined reference components before the cement content grasping work is performed. Measure the content of the reference component of. Then, the measurement by the fluorescent X-ray analyzer 1 is based on the measured value of the content of the predetermined reference component by the fluorescent X-ray analyzer 1 and the theoretical value of the content of the predetermined reference component when the test piece is prepared. It is preferable to know in advance the correction coefficient that brings the value closer to the theoretical value. Then, in the cement content grasping work, it is preferable to grasp the content rate of the cement-based solidifying material in the cement-improved soil CS based on the correction value obtained by correcting the measured value by the fluorescent X-ray analyzer 1 with the correction coefficient. By grasping the correction coefficient of the fluorescent X-ray analyzer 1 to be used in advance, the content rate of the cement-based solidifying material in the cement-improved soil CS can be grasped more accurately. It is more advantageous to accurately estimate the strength after the prescribed curing period.

なお、上述した所定の基準成分は、セメント改良土CSにおける所定の基準成分の含有率に基づいてセメント系固化材の含有率を把握できる成分であればよく、蛍光X線分析装置1により所定の基準成分として、例えば、カルシウム、ケイ素、鉄、アルミニウム以外の成分を測定することもできる。本発明の推定方法は、地盤改良工事を行う施工現場に限らず、例えば、研究所において対象土に対するセメント系固化材の混合比率とセメント改良土CSの規定の養生期間後の強度との関係を調査する試験等で採用することもできる。上記では、水セメント比とセメント改良土CSの規定の養生期間後の強度との関係データに基づいて、規定の養生期間後のセメント改良土CSの強度を推定する場合を例示したが、同様に、セメント水比とセメント改良土CSの規定の養生期間後の強度との関係データに基づいて、規定の養生期間後のセメント改良土CSの強度を推定する構成にすることもできる。 The above-mentioned predetermined reference component may be a component capable of grasping the content of the cement-based solidifying material based on the content of the predetermined reference component in the cement-improved soil CS, and is predetermined by the fluorescent X-ray analyzer 1. As a reference component, for example, a component other than calcium, silicon, iron, and aluminum can be measured. The estimation method of the present invention is not limited to the construction site where the ground improvement work is carried out. It can also be used in tests to be investigated. In the above, the case of estimating the strength of the cement-improved soil CS after the specified curing period based on the relationship data between the water-cement ratio and the strength of the cement-improved soil CS after the specified curing period has been illustrated. Based on the relationship data between the cement water ratio and the strength of the cement-improved soil CS after the specified curing period, the strength of the cement-improved soil CS after the specified curing period can be estimated.

1 蛍光X線分析装置
2 トリガー
3 表示画面
CS セメント改良土
R X線
1 Fluorescent X-ray analyzer 2 Trigger 3 Display screen CS Cement improved soil RX-ray

Claims (8)

対象土とセメント系固化材とを混合撹拌することにより形成されるセメント改良土の規定の養生期間後の強度を、予め把握しておいた前記セメント改良土の規定の養生期間後の強度と水セメント比との関係データを用いて推定するセメント改良土の強度の推定方法において、
前記セメント改良土の前記規定の養生期間が経過する前に、前記セメント改良土の含水率を把握する含水率把握作業と、前記セメント改良土に蛍光X線分析装置によりX線を照射して前記セメント改良土に含まれる所定の基準成分を測定し、その測定した所定の基準成分の含有率に基づいて前記セメント改良土における前記セメント系固化材の含有率を把握するセメント含有率把握作業とを行い、その把握した前記セメント改良土における前記含水率と前記セメント系固化材の含有率とに基づいて前記セメント改良土の水セメント比を算出し、その算出した水セメント比と予め把握しておいた前記関係データとに基づいて前記規定の養生期間後の前記セメント改良土の強度を推定することを特徴とするセメント改良土の強度の推定方法。
The strength of the cement-improved soil formed by mixing and stirring the target soil and the cement-based solidifying material after the specified curing period, and the strength of the cement-improved soil after the specified curing period and water. In the method of estimating the strength of cement-improved soil, which is estimated using the relational data with the cement ratio,
Before the stipulated curing period of the cement-improved soil elapses, the work of grasping the water content of the cement-improved soil and the work of irradiating the cement-improved soil with X-rays by a fluorescent X-ray analyzer are described. The cement content grasping work of measuring a predetermined reference component contained in the cement-improved soil and grasping the content of the cement-based solidifying material in the cement-improved soil based on the measured content of the predetermined reference component. Then, the water-cement ratio of the cement-improved soil is calculated based on the water content of the cement-improved soil and the content of the cement-based solidifying material, and the calculated water-cement ratio is grasped in advance. A method for estimating the strength of cement-improved soil, which comprises estimating the strength of the cement-improved soil after the prescribed curing period based on the related data.
前記所定の基準成分として、前記セメント改良土に含まれるカルシウムを測定する請求項1に記載のセメント改良土の強度の推定方法。 The method for estimating the strength of cement-improved soil according to claim 1, wherein calcium contained in the cement-improved soil is measured as the predetermined reference component. 前記所定の基準成分として、前記セメント改良土に含まれるケイ素または鉄またはアルミニウムのいずれかを測定する請求項1に記載のセメント改良土の強度の推定方法。 The method for estimating the strength of cement-improved soil according to claim 1, wherein any of silicon, iron, or aluminum contained in the cement-improved soil is measured as the predetermined reference component. 前記対象土と前記セメント系固化材とを混合撹拌してから3日以内の前記セメント改良土の改良初期に、前記規定の養生期間後の前記セメント改良土の強度を推定する請求項1〜3のいずれかに記載のセメント改良土の強度の推定方法。 Claims 1 to 3 for estimating the strength of the cement-improved soil after the prescribed curing period at the initial stage of improvement of the cement-improved soil within 3 days after mixing and stirring the target soil and the cement-based solidifying material. The method for estimating the strength of cement-improved soil according to any one of. 前記含水率把握作業と、前記セメント含有率把握作業とをそれぞれ前記セメント改良土の別々の試料を用いて並行して行う請求項1〜4のいずれかに記載のセメント改良土の強度の推定方法。 The method for estimating the strength of cement-improved soil according to any one of claims 1 to 4, wherein the water content grasping work and the cement content grasping work are performed in parallel using separate samples of the cement-improved soil. .. 前記含水率把握作業で乾燥させた前記セメント改良土の試料を使用して前記セメント含有率把握作業を行う請求項1〜5のいずれかに記載のセメント改良土の強度の推定方法。 The method for estimating the strength of cement-improved soil according to any one of claims 1 to 5, wherein the cement-improved soil grasping work is performed using a sample of the cement-improved soil dried in the water content grasping work. 前記セメント系固化材を混合する前の前記対象土に含まれている前記所定の基準成分の含有率を予め把握しておき、その前記対象土に元々含まれている前記所定の基準成分の含有率と、前記蛍光X線分析装置によって測定した前記セメント改良土に含まれる前記所定の基準成分の含有率とに基づいて、前記セメント改良土における前記セメント系固化材の含有率を把握する請求項1〜6のいずれかに記載のセメント改良土の強度の推定方法。 The content of the predetermined reference component contained in the target soil before mixing the cement-based solidifying material is grasped in advance, and the content of the predetermined reference component originally contained in the target soil is contained. A claim for grasping the content of the cement-based solidifying material in the cement-improved soil based on the rate and the content of the predetermined reference component contained in the cement-improved soil measured by the fluorescent X-ray analyzer. The method for estimating the strength of cement-improved soil according to any one of 1 to 6. 前記セメント含有率把握作業を行う前に、前記所定の基準成分の含有率を異ならせて作成した複数種類のセメント改良土の試験体に対して、前記蛍光X線分析装置による前記所定の基準成分の含有率の測定を行い、前記蛍光X線分析装置による前記試験体における前記所定の基準成分の含有率の測定値と、前記試験体を作成したときの前記所定の基準成分の含有率の理論値とに基づいて、前記蛍光X線分析装置による前記測定値を前記理論値に近づける補正係数を予め把握しておき、前記セメント含有率把握作業では前記蛍光X線分析装置による前記測定値を前記補正係数で補正した補正値に基づいて、前記セメント改良土における前記セメント系固化材の含有率を把握する請求項1〜7のいずれかに記載のセメント改良土の強度の推定方法。 Before performing the cement content grasping work, the predetermined reference component by the fluorescent X-ray analyzer was applied to a plurality of types of cement-improved soil test specimens prepared by varying the content of the predetermined reference component. The measured value of the content of the predetermined reference component in the test piece by the fluorescent X-ray analyzer and the theory of the content of the predetermined reference component when the test piece was prepared. Based on the value, the correction coefficient that brings the measured value by the fluorescent X-ray analyzer closer to the theoretical value is grasped in advance, and in the cement content grasping work, the measured value by the fluorescent X-ray analyzer is used. The method for estimating the strength of cement-improved soil according to any one of claims 1 to 7, wherein the content of the cement-based solidifying material in the cement-improved soil is grasped based on the correction value corrected by the correction coefficient.
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