JP2009150130A - Backfill grouting material - Google Patents

Backfill grouting material Download PDF

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JP2009150130A
JP2009150130A JP2007329250A JP2007329250A JP2009150130A JP 2009150130 A JP2009150130 A JP 2009150130A JP 2007329250 A JP2007329250 A JP 2007329250A JP 2007329250 A JP2007329250 A JP 2007329250A JP 2009150130 A JP2009150130 A JP 2009150130A
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cement
injection material
weight
backfilling injection
reducing agent
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Shinji Urano
真次 浦野
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Shimizu Construction Co Ltd
Shimizu Corp
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Shimizu Construction Co Ltd
Shimizu Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a backfill grouting material capable of exhibiting a desired strength by curing in a short time after a construction while securing the flowability of the backfill grouting material during the backfill grouting under such a low temperature environment as on a frozen ground. <P>SOLUTION: This backfill grouting material includes a cement, water, a high-performance water reducing agent, and a cold resistant hardening accelerator. By the high performance water reducing agent contained in the backfill grouting material, the flowability of the backfill grouting material is held for a predetermined time immediately after the material is mixed. Also, when the cold resistant hardening accelerator is contained in the material, the desired initial strength of the material is exhibited by curing the material in a short time under the low temperature environment. In addition to the material, a thickener for securing the underwater non-separability of cement and an expanding material for preventing cement from being self-contracted may be contained in the material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、シールド工法において使用される裏込め注入材に関するものである。   The present invention relates to a backfilling injection material used in a shield method.

シールド工法は、シールド掘削機に設けたジャッキ等の推進装置を用いて、後方に順次覆工されたセグメントを押圧し、その反力をシールド掘削機の推力として掘進しながらトンネルを構築していく工法である。このシールド工法では、地山の掘削面とセグメントとの間の空隙部分に裏込め注入材を注入し、固化させることによって、地山の変形を最小限に抑えるようにしている。この裏込め注入材としては、通常、セメントやモルタル等が用いられる。   The shield method uses a propulsion device such as a jack provided on the shield excavator to press the segments that are sequentially lined backward, and builds a tunnel while digging the reaction force as the thrust of the shield excavator It is a construction method. In this shield method, backfill injection material is injected into the gap between the excavation surface of the natural ground and the segment and solidified to minimize deformation of the natural ground. As this backfilling injection material, cement or mortar is usually used.

上記シールド工法の一つとして、地山の止水や強度増加等を目的とした地盤凍結工法が知られている。地盤凍結工法とは、地盤内に凍結管を打ち込み、凍結管に液体窒素等を流し込んで地盤中に液体窒素を充填することによって地盤を凍結させ、地下水の流動を防止した上で作業を実施し、作業完了後に地盤の凍結を解除して、元の地盤に復帰させる工法である。   As one of the shield methods, there is known a ground freezing method for the purpose of water stoppage and strength increase of natural ground. The ground freezing method is a method in which a freezing pipe is driven into the ground, liquid nitrogen is poured into the freezing pipe, and the ground is frozen by filling the ground with liquid nitrogen to prevent the flow of groundwater. This is a method of releasing the freezing of the ground after completion of the work and returning it to the original ground.

凍結工法を行う場合、地山の掘削面とセグメントとの間の空隙部分の雰囲気温度は0℃〜5℃程度となる。このため、凍結工法において通常の常温施工用の裏込め注入材を用いると、地盤とセグメントとの間に注入された裏込め注入材の硬化が阻害され、シールドの掘進に必要な強度を発現させることができないという問題が生じる。そこで、凍結工法のような低温環境下においても所定の強度を発現させることが可能な裏込め注入材が提案されている(例えば特許文献1を参照)。特許文献1に記載された裏込め注入材は、セメント、フライアッシュ、粘土鉱物及び水を所定の比率で混練した液体と、珪酸ソーダ水溶液とを混合したものであり、雰囲気温度が0℃以下であっても凍結崩壊せず、雰囲気温度が常温に達した後に所定の強度を発現するものである。   When the freezing method is performed, the atmospheric temperature of the gap between the excavated surface of the natural ground and the segment is about 0 ° C to 5 ° C. For this reason, if the backfilling injection material for normal room temperature construction is used in the freezing method, hardening of the backfilling injection material injected between the ground and the segment is hindered, and the strength necessary for shield digging is expressed. The problem of being unable to do so arises. Therefore, a backfilling injection material has been proposed that can exhibit a predetermined strength even in a low temperature environment such as a freezing method (see, for example, Patent Document 1). The backfilling injection material described in Patent Document 1 is a mixture of a liquid obtained by kneading cement, fly ash, clay mineral and water at a predetermined ratio and a sodium silicate aqueous solution, and the ambient temperature is 0 ° C. or less. Even if it exists, it does not freeze and collapse and develops a predetermined strength after the ambient temperature reaches room temperature.

特開平7−291703号公報JP-A-7-291703

ところで、上述した裏込め注入材は、シールドにおけるジャッキの推力を確保するのに必要な強度を、工期の都合上、1日程度という短時間で発現させることが要求される。特許文献1に記載された裏込め注入材は、雰囲気温度が常温に達した後、所定の強度が発現するまでに数日程度を要する。従って、低温環境下での短時間の養生では必要な強度を発現することができず、工期に遅れが生じるという問題がある。   By the way, the above-mentioned backfilling injection material is required to develop the strength necessary for securing the thrust of the jack in the shield in a short time of about one day for the convenience of the construction period. The backfilling injection material described in Patent Document 1 requires several days until the predetermined strength is developed after the atmospheric temperature reaches room temperature. Therefore, there is a problem that the required strength cannot be expressed by a short-term curing in a low-temperature environment, and the construction period is delayed.

また、裏込め注入材を地上で混練した後、ポンプによって裏込め注入材を注入箇所まで圧送し、注入作業を完了させるまでには1〜2時間程度を要する。特に、掘削深度が大きい場合には裏込め注入材の圧送距離が長距離になるため、注入作業の施工性を確保するために、比較的長時間に亘って裏込め注入材の流動性を保持する必要がある。   Further, after the backfilling injection material is kneaded on the ground, it takes about 1 to 2 hours to pump the backfilling injection material to the injection site by a pump and complete the injection operation. In particular, when the excavation depth is large, the pumping distance of the backfilling injection material becomes long, so the fluidity of the backfilling injection material is maintained for a relatively long time to ensure the workability of the injection work. There is a need to.

本発明は、上記の点に鑑み、凍結地盤等の低温環境下において、裏込め注入を行う際の流動性を確保しつつ、施工後、短時間の養生で所望の強度を発現させることができる裏込め注入材を提供することを目的とする。   In view of the above points, the present invention is capable of expressing desired strength with short-term curing after construction while ensuring fluidity when performing backfill injection in a low-temperature environment such as frozen ground. The object is to provide a backfilling injection.

本発明の請求項1に記載の裏込め注入材は、地山の掘削面とセグメントとの間の空隙に注入されるものであり、セメント、水、高性能減水剤及び耐寒硬化促進剤を含有することを特徴とする。   The backfilling injection material according to claim 1 of the present invention is injected into the gap between the excavation surface of the natural ground and the segment, and contains cement, water, a high-performance water reducing agent and a cold hardening accelerator. It is characterized by doing.

また、本発明の請求項2に記載の裏込め注入材は、上記請求項1において、さらに増粘剤を含有することを特徴とする。   Further, the backfilling injection material according to claim 2 of the present invention is characterized in that in the above-mentioned claim 1, it further contains a thickener.

また、本発明の請求項3に記載の裏込め注入材は、上記請求項1において、さらに膨張材を含有することを特徴とする。   Further, the backfilling injection material according to claim 3 of the present invention is characterized in that, in the above-mentioned claim 1, it further contains an expansion material.

また、本発明の請求項4に記載の裏込め注入材は、上記請求項1において、前記高性能減水剤がポリカルボン酸系高性能減水剤であり、前記セメントの重量に対して0.8重量%〜2重量%含有することを特徴とする。   The backfilling injection material according to claim 4 of the present invention is the backfilling injection material according to claim 1, wherein the high-performance water reducing agent is a polycarboxylic acid-based high-performance water reducing agent, and the weight of the cement is 0.8. It is characterized by containing 2% by weight to 2% by weight.

また、本発明の請求項5に記載の裏込め注入材は、上記請求項1おいて、前記耐寒硬化促進剤が亜硝酸塩及び/又は硝酸塩を主成分とするものであり、前記セメント100kg当たり1リットル〜3リットル含有することを特徴とする。   The backfilling injection material according to claim 5 of the present invention is the backfilling injection material according to claim 1, wherein the cold-hardening accelerator is mainly composed of nitrite and / or nitrate, and 1 per 100 kg of the cement. It contains 1 to 3 liters.

また、本発明の請求項6に記載の裏込め注入材は、上記請求項2おいて、前記増粘剤がアルキルアリルスルフォン酸塩及びアルキルアンモニウム塩とを主成分とするものであり、前記水の重量に対して1.0重量%〜2.5重量%含有することを特徴とする。   The backfill injection material according to claim 6 of the present invention is the backfill injection material according to claim 2, wherein the thickener is composed mainly of an alkylallyl sulfonate and an alkyl ammonium salt, and the water It is characterized by containing 1.0% by weight to 2.5% by weight with respect to the weight.

また、本発明の請求項7に記載の裏込め注入材は、上記請求項3おいて、前記膨張材の含有量が前記セメントの重量に対して2重量%〜4重量%であることを特徴とする。   The backfilling injection material according to claim 7 of the present invention is characterized in that, in the above-mentioned claim 3, the content of the expansion material is 2% by weight to 4% by weight with respect to the weight of the cement. And

また、本発明の請求項8に記載の裏込め注入材は、上記請求項1から7のいずれか一つにおいて、前記セメントとして早強セメントを適用したことを特徴とする。   Further, the backfilling injection material according to claim 8 of the present invention is characterized in that, in any one of claims 1 to 7, an early-strength cement is applied as the cement.

本発明の裏込め注入材によれば、高性能減水剤及び耐寒硬化促進剤を含有させたことで、裏込め注入を施工する際の流動性を確保しつつ、施工後、低温環境下での短時間の養生で所望の強度を発現させることができる。その結果、凍結工法における裏込め注入や厳冬期における裏込め注入の施工効率を著しく向上させることができる。   According to the backfilling injection material of the present invention, by including a high-performance water reducing agent and a cold-hardening accelerator, ensuring fluidity when constructing backfilling injection, after construction, in a low-temperature environment Desired strength can be expressed with a short-term curing. As a result, it is possible to remarkably improve the construction efficiency of backfill injection in the freezing method and backfill injection in the severe winter season.

以下に、本発明の裏込め注入材の好適な実施の形態について詳細に説明する。   Hereinafter, preferred embodiments of the backfilling injection material of the present invention will be described in detail.

本実施の形態である裏込め注入材は、セメント、水、高性能減水剤及び耐寒硬化促進剤とを混合することにより得られる。高性能減水剤は、上記材料を混合した直後から所定時間の間、裏込め注入の施工性を確保するのに必要な流動性を保持するために添加されるものである。また、耐寒硬化促進剤は、低温環境下で裏込め注入材を養生させた場合に、所望の初期強度を短時間で発現させるために添加されるものである。   The backfilling injection material according to this embodiment is obtained by mixing cement, water, a high-performance water reducing agent, and a cold hardening accelerator. The high-performance water reducing agent is added to maintain the fluidity necessary to ensure the workability of backfill injection for a predetermined time immediately after mixing the above materials. The cold-hardening accelerator is added to develop a desired initial strength in a short time when the backfilling injection material is cured in a low temperature environment.

セメントは、早強セメント、普通セメント等のポルトランドセメントを使用することができるが、所望の強度をより速く発現させるために早強セメントを用いるのが好ましい。本実施の形態では、水セメント比30%〜40%程度のセメントペーストとしている。ここで、「セメントペースト」とはセメントと水を構成材料としたものであり、「水セメント比」とは、セメントに対する水の重量比をいう。なお、本実施の形態では、水セメント比の水の重量に、後述する高性能減水剤、耐寒硬化促進剤及び増粘剤の重量を含むものとする。   As the cement, Portland cement such as early-strength cement and ordinary cement can be used, but early-strength cement is preferably used in order to develop desired strength more quickly. In this embodiment, the cement paste has a water cement ratio of about 30% to 40%. Here, “cement paste” uses cement and water as constituent materials, and “water cement ratio” means the weight ratio of water to cement. In the present embodiment, the weight of water with a water-cement ratio includes the weight of a high-performance water reducing agent, a cold-hardening accelerator, and a thickening agent, which will be described later.

なお、セグメントに形成された裏込め注入材の注入孔は、直径5cm以下とし、逆止弁の付いた構造となっている。従って、この注入孔から空隙全体に満遍なく裏込め注入材を充填させるための施工性を考慮すると、モルタルよりもセメントペーストを用いることが好ましい。但し、注入孔の直径が比較的大きい場合など、詰まるおそれがない場合には、セメントペーストを用いる替りに、水セメント比30%〜40%のモルタルを適用してもよい。ここで、「モルタル」とは、セメント、水、細骨材(砂)を構成材料としたものである。また、セメントにフライアッシュ、高炉スラグ等を混合したものを適用することも可能である。   In addition, the injection hole of the backfill injection material formed in the segment has a diameter of 5 cm or less and has a structure with a check valve. Therefore, in consideration of the workability for filling the back-filling injection material evenly from the injection hole to the entire gap, it is preferable to use cement paste rather than mortar. However, when there is no possibility of clogging such as when the diameter of the injection hole is relatively large, a mortar having a water cement ratio of 30% to 40% may be applied instead of using the cement paste. Here, “mortar” is a material composed of cement, water, and fine aggregate (sand). It is also possible to apply cement mixed with fly ash, blast furnace slag, or the like.

高性能減水剤(JIS A 6204)は、減水剤よりも高い減水性能及びスランプ保持性能を有する公知の混和剤である。ここで、減水剤とは、コンクリートの単位水量を減少させるための混和剤であり、セメント粒子を分散させてセメントペーストの流動性を高めるために用いられるものである。高性能減水剤の種類は、ポリカルボン酸系、ナフタリン系、メラミン系及びアミノスルホン酸系があるが、特にポリカルボン酸系を用いるのが好ましい。高性能減水剤の含有量は、セメントの重量に対して0.8重量%〜2重量%程度とするのが好ましい。含有量がセメント重量に対して0.8%を下回る場合、所望の流動性が得られない可能性がある。また、含有量が2重量%を超えた場合、セメントペーストやモルタルが材料分離を生じる状態となる。   High performance water reducing agent (JIS A 6204) is a known admixture having higher water reducing performance and slump retention performance than water reducing agents. Here, the water reducing agent is an admixture for reducing the unit water amount of concrete, and is used to disperse cement particles and increase the fluidity of cement paste. There are polycarboxylic acid type, naphthalene type, melamine type and aminosulfonic acid type as the kind of the high performance water reducing agent, and it is particularly preferable to use the polycarboxylic acid type. The content of the high-performance water reducing agent is preferably about 0.8 wt% to 2 wt% with respect to the weight of the cement. If the content is less than 0.8% with respect to the cement weight, the desired fluidity may not be obtained. Moreover, when content exceeds 2 weight%, a cement paste and mortar will be in the state which produces material separation.

なお、高性能減水剤の替わりに高性能AE減水剤を用いてもよい。高性能AE減水剤とは、AE減水剤よりも高い減水性能及びスランプ保持性能を有する公知の混和材である。また、AE減水剤とは、AE剤、減水剤両方の効果を兼ね備えた混和剤であり、AE剤は、微小な独立した空気の泡をコンクリート中に一様に分布させるために用いる混和剤である。高性能AE減水剤の含有量は上記の高性能減水剤の含有量と同様とする。   A high-performance AE water reducing agent may be used instead of the high-performance water reducing agent. The high-performance AE water reducing agent is a known admixture having higher water reducing performance and slump retention performance than the AE water reducing agent. The AE water reducing agent is an admixture having the effects of both the AE agent and the water reducing agent, and the AE agent is an admixture used to uniformly distribute minute and independent air bubbles in the concrete. is there. The content of the high performance AE water reducing agent is the same as the content of the above high performance water reducing agent.

耐寒硬化促進剤は、コンクリート中の水分の凍結温度を下げるとともに、0℃前後の低温環境下での初期強度を促進させる機能を有する公知の混和剤である。耐寒硬化促進剤は、硝酸カルシウム等の硝酸塩及び/又は亜硝酸カルシウム等の亜硝酸塩を主成分とするものが好ましく用いられる。耐寒硬化促進剤の含有量は、セメント100kg当たり0.3リットル〜3リットル、好ましくは1リットル〜3リットルである。含有量が0.3リットルを下回る場合、必要な初期強度が得られない可能性がある。また、含有量が3リットルを超えた場合、流動性が急激に低下する状況となる。   The cold-hardening accelerator is a known admixture that has a function of lowering the freezing temperature of moisture in the concrete and promoting the initial strength in a low-temperature environment around 0 ° C. As the cold hardening accelerator, those mainly composed of nitrates such as calcium nitrate and / or nitrites such as calcium nitrite are preferably used. The content of the cold hardening accelerator is 0.3 to 3 liters, preferably 1 to 3 liters per 100 kg of cement. If the content is less than 0.3 liter, the necessary initial strength may not be obtained. Moreover, when content exceeds 3 liters, it will be in the state where fluidity | liquidity falls rapidly.

さらに、上記の材料に加えて、材料の水中不分離性を確保するための増粘剤と、セメントの自己収縮を防止する膨張材とを含有させてもよい。以下、増粘剤と膨張材について説明する。   Further, in addition to the above materials, a thickening agent for ensuring the non-separability of the material in water and an expansion material for preventing self-shrinkage of the cement may be included. Hereinafter, the thickener and the expansion material will be described.

例えば地盤の掘削面とセグメントとの間の空隙が地下水で充たされている場合など、水中にセメントペーストを注入する場合、セメントペーストの材料分離が生じる。そこで、増粘剤を添加することで、裏込め注入材の粘性を増大させ、水中での材料分離を防止する。これにより、裏込め注入材を水中に充填した場合であっても、所望の強度を発現させることができる。増粘剤は、セメントの水和を遅延させないタイプのものを用いるのが好ましく、本実施の形態ではアルキルアリルスルフォン酸塩とアルキルアンモニウム塩とを主成分とするものを適用している。増粘剤の含有量は、水の重量に対して1.0〜2.5重量%とするのが好ましい。増粘剤の含有量が水の重量に対して1.0%を下回る場合、所望の粘性が得られない可能性がある。また、含有量が2.5%を超えた場合、粘性が過大となり、施工性が低下する状態となる。なお、地下水の少ない場所に施工する場合など、水分の少ない場所に施工する場合には、必ずしも増粘剤を添加する必要性はない。   When cement paste is injected into water, for example, when the space between the excavation surface of the ground and the segment is filled with groundwater, material separation of the cement paste occurs. Therefore, by adding a thickener, the viscosity of the backfilling injection material is increased and material separation in water is prevented. Thereby, even if it is a case where backfilling injection material is filled in water, desired intensity | strength can be expressed. It is preferable to use a thickening agent that does not delay the hydration of the cement. In this embodiment, a thickener mainly composed of an alkyl allyl sulfonate and an alkyl ammonium salt is used. The content of the thickener is preferably 1.0 to 2.5% by weight with respect to the weight of water. When the content of the thickener is less than 1.0% with respect to the weight of water, the desired viscosity may not be obtained. Moreover, when content exceeds 2.5%, viscosity will become excessive and will be in the state which workability falls. In addition, when it constructs in a place with little moisture, such as when constructing in a place with little groundwater, it is not always necessary to add a thickener.

また、セメントペーストは、水和反応の進行によって体積が減少し、収縮を起こす(自己収縮)。このため、掘削地盤とセグメントとの間の空隙に裏込め注入材を注入した後、所定の期間が経過すると、裏込め注入材と掘削地盤との間、及び、裏込め注入材とセグメントとの間に若干の隙間が生じ、この隙間を通じて地下水が坑内に浸入する虞がある。そこで、膨張材を添加することでセメントペーストの自己収縮を防止し、地下水の坑内への浸入を防止する。本実施の形態では、膨張材として石灰系のものを適用している。膨張材の含有量はセメントの重量に対して2重量%〜4重量%とするのが好ましい。なお、坑内の止水性が要求されず、裏込め注入材の若干の体積収縮が許容される場合には、膨張材を省略することも可能である。   Also, the cement paste shrinks due to the progress of the hydration reaction and causes shrinkage (self-shrinking). For this reason, after injecting the backfilling injection material into the gap between the excavation ground and the segment, when a predetermined period elapses, the backfilling injection material and the excavation ground, and between the backfilling injection material and the segment There is a slight gap between them, and groundwater may enter the mine through this gap. Therefore, by adding an expansion material, self-shrinkage of the cement paste is prevented and infiltration of groundwater into the mine is prevented. In the present embodiment, a lime-based material is applied as the expansion material. The content of the expansion material is preferably 2% by weight to 4% by weight with respect to the weight of the cement. In addition, in the case where the waterstop in the mine is not required and the volume shrinkage of the backfilling injection material is allowed, the expansion material can be omitted.

以下、実施例により本発明の裏込め注入材について具体的に説明する。   Hereinafter, the backfilling injection material of the present invention will be specifically described with reference to examples.

(試料の作成)
上述した高性能減水剤、耐寒硬化促進剤、増粘剤、膨張材を、表1に示す比率で混合し、試料(実施例1〜18、比較例1〜5)を作成した。セメントは早強ポルトランドセメントを用い、水セメント比は30%、35%、40%の3種類とした。なお、すべての実施例及び比較例において、高性能減水剤として、花王株式会社製の「マイテイ21HP」(液体)を用いた。また、耐寒硬化促進剤として、株式会社ポゾリス物産製の「ポズテック99」(液体)を用いた。また、増粘剤として、花王株式会社製の「ビスコトップ100A,100B」(2液タイプ:以下、各液をA液、B液という)を用いた。なお、増粘剤として1液タイプの「ビスコトップ200L」又は粉末タイプの「ビスコトップ200P」を用いてもよい。また、膨張材は、太平洋マテリアル株式会社製の「N−EX」(粉体)を用いた。
(Sample preparation)
The above-described high-performance water reducing agent, cold hardening accelerator, thickener, and expansion material were mixed in the ratios shown in Table 1 to prepare samples (Examples 1 to 18, Comparative Examples 1 to 5). As the cement, early-strength Portland cement was used, and the water cement ratio was set to three types of 30%, 35% and 40%. In all Examples and Comparative Examples, “Mighty 21HP” (liquid) manufactured by Kao Corporation was used as a high-performance water reducing agent. Moreover, “Pozztec 99” (liquid) manufactured by Pozoris Co., Ltd. was used as a cold hardening accelerator. As a thickener, “Visco Top 100A, 100B” manufactured by Kao Co., Ltd. (2 liquid type: each liquid is hereinafter referred to as A liquid and B liquid) was used. As the thickener, one-component type “Visco Top 200L” or powder type “Visco Top 200P” may be used. Further, “N-EX” (powder) manufactured by Taiheiyo Material Co., Ltd. was used as the expansion material.

表1において、高性能減水剤の添加率はセメント量に対する比率であり、耐寒硬化促進剤の添加率はセメント100kg当たりのリットル数であり、膨張材の添加率はセメント量に対する比率である。また、増粘剤の添加率は、A液、B液それぞれの水量に対する比率である(例えば2.0%の場合、A液とB液をそれぞれ水量に対して2.0%ずつ添加する)。また、表1に示す水の重量には、高性能減水剤、耐寒硬化促進剤及び増粘剤のA液の添加量が含まれている。   In Table 1, the addition rate of the high-performance water reducing agent is a ratio to the amount of cement, the addition rate of the cold hardening accelerator is the number of liters per 100 kg of cement, and the addition rate of the expansion material is a ratio to the amount of cement. Moreover, the addition rate of a thickener is the ratio with respect to the amount of water of each of A liquid and B liquid (For example, in the case of 2.0%, A liquid and B liquid are added 2.0% each with respect to the amount of water). . In addition, the weight of water shown in Table 1 includes the amount of addition of the high-performance water reducing agent, cold hardening accelerator and thickener A solution.

(混練手順)
常温(20℃)の室内において、セメントと膨張材に、水、高性能減水剤、耐寒硬化促進剤及び増粘剤のA液を混合し、1分間練り混ぜた後、増粘剤のB液を投入し、さらに1分間練り混ぜて、各試料を製造した。なお、表1に示すように、実施例15〜18では膨張材を省略した。また、比較例1〜5では、耐寒硬化促進剤及び膨張材を省略した。また、実施例18と比較例4,5には砂を添加し、モルタルとした。
(Kneading procedure)
In a room temperature (20 ° C) room, water, high-performance water reducing agent, cold-hardening accelerator and thickener A liquid are mixed with cement and expansion material, kneaded for 1 minute, and thickener B liquid Was added and kneaded for 1 minute to produce each sample. In addition, as shown in Table 1, the expansion material was abbreviate | omitted in Examples 15-18. Moreover, in Comparative Examples 1-5, the cold-hardening accelerator and the expansion material were omitted. Moreover, sand was added to Example 18 and Comparative Examples 4 and 5 to obtain mortar.

Figure 2009150130
Figure 2009150130

(フロー値の測定)
上記混練手順で作成した試料をコーンに入れ、コーンから試料を流したときの試料の広がり(直径)を測定することにより、試料の流動性を評価した。フロー値の測定は、混練直後、混練から60分経過後、120分経過後、180分経過後に行い、流動性の経時変化を測定した。なお、裏込め注入材として要求される性能は、シールド工事の規模、形状寸法、充填箇所の空隙の大きさなどによって異なるが、掘削径φが5m程度の例では、混練直後のフロー値が350mm×350mm以上、120分後のフロー値が250mm×250mm以上である。測定結果を表2に示す。
(Measurement of flow value)
The fluidity of the sample was evaluated by placing the sample prepared by the kneading procedure in a cone and measuring the spread (diameter) of the sample when the sample was flowed from the cone. The flow value was measured immediately after kneading, after 60 minutes from kneading, after 120 minutes and after 180 minutes, and the change in fluidity with time was measured. The performance required for the backfilling injection material varies depending on the scale, shape and size of the shield construction, the size of the gap at the filling location, etc., but in the example where the excavation diameter φ is about 5 m, the flow value immediately after kneading is 350 mm. × 350 mm or more, the flow value after 120 minutes is 250 mm × 250 mm or more. The measurement results are shown in Table 2.

(初期強度の測定)
上記混練手順で作成した試料を所定の容器に充填し、5℃の室内(大気中)で養生した。コンクリート圧縮試験装置を用いて、1日養生後と28日養生後の各試料の圧縮強度をそれぞれ測定した。裏込め注入材として要求される性能は、周辺地盤の地盤条件によって変化するが、材齢1日での圧縮強度が1.5N/mm2以上、材齢28日での圧縮強度が15N/mm2以上である。なお、材齢1日の圧縮強度「1.5N/mm2以上」は、シールドにおけるジャッキの推力を確保するのに必要な強度であり、凍結していない場合の裏込め注入材の要求性能と同等である。また、材齢28日の圧縮強度「15N/mm2」は、「給水・換気竪坑センター孔」の花崗岩M級の一軸圧縮強度(10.2N/mm2)を目安としている。測定結果を表2に示す。
(Measurement of initial strength)
A sample prepared by the kneading procedure was filled in a predetermined container and cured in a room at 5 ° C. (in the atmosphere). The compressive strength of each sample after 1-day curing and after 28-day curing was measured using a concrete compression tester. The performance required as a backfilling injection material varies depending on the ground conditions of the surrounding ground, but the compressive strength at the age of 1 day is 1.5 N / mm 2 or more, and the compressive strength at the age of 28 days is 15 N / mm. 2 or more. The compressive strength “1.5 N / mm 2 or more” per day of the age is a strength necessary for securing the thrust of the jack in the shield, and the required performance of the backfilling injection material when it is not frozen. It is equivalent. The compression strength “15 N / mm 2 ” at the age of 28 days is based on the uniaxial compressive strength (10.2 N / mm 2 ) of granite M class “water supply / ventilation shaft hole”. The measurement results are shown in Table 2.

また、上記手順で作成した試料を、水中に設置した容器に充填し、水温5℃の水中にて養生した。大気中の養生の場合と同様に、材齢1日と材齢28日の各試料の圧縮強度をそれぞれ測定した。裏込め注入材として要求される性能は、上記の大気中の養生の場合と同じである。測定結果を表2に示す。なお、表2において、試験を行わなかったものについては空欄とした。   Moreover, the sample created by the said procedure was filled in the container installed in water, and was cured in water with a water temperature of 5 degreeC. As in the case of curing in the air, the compressive strength of each sample of material age 1 day and material age 28 was measured. The performance required as a backfilling injection material is the same as in the case of the above-mentioned curing in the atmosphere. The measurement results are shown in Table 2. In Table 2, those not tested were left blank.

Figure 2009150130
Figure 2009150130

(自己収縮量の測定)
実施例10、実施例13、実施例14及び比較例5を用いて、日本コンクリート工学協会・自己収縮委員会の「セメントペースト、モルタル及びコンクリートの自己収縮及び自己膨張試験方法(案)」に準拠した自己収縮試験を行った。なお、試料は、各実施例につき2個ずつ作成した。まず、上記混練手順で作成した試料を5℃の室内(大気中)で養生した。打込み面にはポリエステルフィルムをかぶせ、乾燥を防止した。材齢1日で脱型し、全体をアルミ箔粘着テープでシールした。ひずみは、東京測器研究所製埋込みひずみ計を試料中央に設置して測定した。温度ひずみは、線膨張係数を10×10-6として処理した。測定結果を図1に示す。
(Measurement of self-shrinkage)
Using Example 10, Example 13, Example 14 and Comparative Example 5 in accordance with “Self-shrinkage and self-expansion test method (draft) of cement paste, mortar and concrete (draft)” of the Japan Concrete Engineering Association Self-Shrinkage Committee A self-shrink test was performed. Two samples were prepared for each example. First, the sample prepared by the kneading procedure was cured in a room (in the atmosphere) at 5 ° C. The driving surface was covered with a polyester film to prevent drying. The mold was removed at 1 day of age, and the whole was sealed with an aluminum foil adhesive tape. The strain was measured by installing an embedded strain meter manufactured by Tokyo Sokki Kenkyujo in the center of the sample. The temperature strain was processed with a linear expansion coefficient of 10 × 10 −6 . The measurement results are shown in FIG.

(考察)
表2から明らかなように、実施例1〜18では、フロー値、大気中打設の場合の圧縮強度、水中打設の場合の圧縮強度のいずれにおいても、上記の要求性能以上の良好な結果が得られた。なお、実施例15〜18は、耐寒硬化促進剤の添加率を1%以下としたため、他の実施例と比べて材齢1日での圧縮強度が低い結果となったが、要求性能(1.5N/mm2)は満足している。これに対して、耐寒促進剤を添加しなかった比較例1〜4は、大気中打設、水中打設いずれにおいても、材齢1日での圧縮強度が要求性能を下回った。
(Discussion)
As is clear from Table 2, in Examples 1 to 18, good results exceeding the above required performance in any of the flow value, the compressive strength in the case of placing in the air, and the compressive strength in the case of placing in the water. was gotten. In Examples 15-18, since the addition rate of the cold-hardening accelerator was set to 1% or less, the compressive strength at one day of age was lower than that of the other examples, but the required performance (1 .5 N / mm 2 ) is satisfied. On the other hand, in Comparative Examples 1 to 4 in which the cold resistance accelerator was not added, the compressive strength at the age of 1 day was lower than the required performance in both in-air placement and underwater placement.

また、図1に示すように、膨張材を添加した実施例10、13、14は、養生開始直後に一端膨張した後、徐々に収縮し、材齢10日程度でほぼ一定の値に収束した。ひずみ量の収束値は0以上であり、試料が収縮していないことが分かる。これに対して、膨張材を添加しなかった比較例5は、養生開始直後から自己収縮を起こしていることが分かる。   In addition, as shown in FIG. 1, Examples 10, 13, and 14 to which the expansion material was added expanded one end immediately after the start of curing, then gradually contracted, and converged to a substantially constant value at about 10 days of age. . The convergence value of the strain amount is 0 or more, and it can be seen that the sample is not contracted. On the other hand, it can be seen that Comparative Example 5 in which no expansion material was added caused self-shrinkage immediately after the start of curing.

以上説明したように、本実施の形態の裏込め注入材によれば、高性能減水剤及び耐寒硬化促進剤を含有させたことで、裏込め注入を施工する際の流動性を確保しつつ、施工後、低温環境下での短時間の養生で所望の強度を発現させることができる。その結果、凍結工法における裏込め注入や厳冬期における裏込め注入の施工効率を向上させることができる。   As described above, according to the backfilling injection material of the present embodiment, by including a high-performance water reducing agent and a cold hardening accelerator, while ensuring fluidity when constructing backfilling injection, After the construction, a desired strength can be expressed by a short time curing under a low temperature environment. As a result, it is possible to improve the efficiency of backfill injection in the freezing method and backfill injection in the severe winter season.

また、本実施の形態の裏込め注入材によれば、上記材料に加えて増粘剤を含有させたことで、裏込め注入材の水中不分離性を向上させることができる。その結果、低温環境下、かつ、水中で養生させた場合であっても、水中での材料分離を起こすことがなく、短時間の養生で所望の強度を発現させることができる。   In addition, according to the backfilling injection material of the present embodiment, in-water non-separability of the backfilling injection material can be improved by adding a thickener in addition to the above materials. As a result, even when it is cured in a low-temperature environment and in water, the desired strength can be expressed with short-term curing without causing material separation in water.

また、本実施の形態の裏込め注入材によれば、上記材料に加えて膨張材を含有させたことで、セメントペーストの自己収縮を防止することができる。その結果、裏込め注入の施工後、低温環境下で養生させた場合に、裏込め注入材と掘削地盤との間、及び、裏込め注入材とセグメントとの間に隙間が生じることがなく、坑内への地下水の侵入を防止することができる。   In addition, according to the backfilling injection material of the present embodiment, self-contraction of the cement paste can be prevented by containing an expansion material in addition to the above materials. As a result, there is no gap between the backfilling injection material and the excavation ground and between the backfilling injection material and the segment when cured under a low temperature environment after the construction of backfilling injection, Intrusion of groundwater into the mine can be prevented.

また、本実施の形態の裏込め注入材によれば、早強セメントを適用したことで、低温環境下での強度発現をより速くすることができ、さらに工期を短縮することが可能となる。   Further, according to the backfilling injection material of the present embodiment, by applying the early strong cement, it is possible to make the strength expression in a low temperature environment faster and further shorten the construction period.

なお、上述した実施の形態では、すべての実施例に増粘剤を添加したが、上述したように、水分の少ない場所に施工する場合には増粘剤を省略してもよく、また、裏込め注入材の若干の体積収縮が許容される場合には膨張材を省略してもよい。また、上述した実施の形態では、すべての実施例及び比較例に早強セメントを適用したが、早強セメントに替えて普通セメントを適用することも可能である。但し、普通セメントを適用した場合、早強セメントを適用した場合よりも強度の発現が遅れるため、耐寒硬化促進剤の添加量を増やす必要がある。   In the above-described embodiment, the thickener is added to all the examples. However, as described above, the thickener may be omitted when the construction is performed in a place with low moisture. The expansion material may be omitted if a slight volume shrinkage of the filling material is allowed. In the above-described embodiment, the early strong cement is applied to all the examples and the comparative examples. However, it is also possible to apply ordinary cement instead of the early strong cement. However, when ordinary cement is applied, strength development is delayed as compared with the case where early strong cement is applied, so it is necessary to increase the amount of cold hardening accelerator added.

自己収縮試験の測定結果を示すグラフである。It is a graph which shows the measurement result of a self-shrink test.

Claims (8)

地山の掘削面とセグメントとの間の空隙に注入される裏込め注入材であって、
セメント、水、高性能減水剤及び耐寒硬化促進剤を含有することを特徴とする裏込め注入材。
A backfilling injection material that is injected into the gap between the excavation surface of the natural ground and the segment,
A backfilling injection material characterized by containing cement, water, a high-performance water reducing agent, and a cold hardening accelerator.
さらに増粘剤を含有することを特徴とする請求項1に記載の裏込め注入材。   The backfilling injection material according to claim 1, further comprising a thickener. さらに膨張材を含有することを特徴とする請求項1に記載の裏込め注入材。   The backfilling injection material according to claim 1, further comprising an expansion material. 前記高性能減水剤がポリカルボン酸系高性能減水剤であり、
前記セメントの重量に対して0.8重量%〜2重量%含有することを特徴とする請求項1に記載の裏込め注入材。
The high-performance water reducing agent is a polycarboxylic acid-based high-performance water reducing agent,
2. The backfilling injection material according to claim 1, comprising 0.8 to 2% by weight based on the weight of the cement.
前記耐寒硬化促進剤が亜硝酸塩及び/又は硝酸塩を主成分とするものであり、前記セメント100kg当たり1リットル〜3リットル含有することを特徴とする請求項1に記載の裏込め注入材。   The backfilling injection material according to claim 1, wherein the cold hardening accelerator contains nitrite and / or nitrate as a main component and is contained in an amount of 1 to 3 liters per 100 kg of the cement. 前記増粘剤がアルキルアリルスルフォン酸塩及びアルキルアンモニウム塩とを主成分とするものであり、前記水の重量に対して1.0重量%〜2.5重量%含有することを特徴とする請求項2に記載の裏込め注入材。   The thickener is mainly composed of an alkyl allyl sulfonate and an alkyl ammonium salt, and contains 1.0% by weight to 2.5% by weight with respect to the weight of the water. Item 3. The backfilling injection material according to item 2. 前記膨張材の含有量が前記セメントの重量に対して2重量%〜4重量%であることを特徴とする請求項3に記載の裏込め注入材。   The backfilling injection material according to claim 3, wherein the content of the expansion material is 2% by weight to 4% by weight with respect to the weight of the cement. 前記セメントとして早強セメントを適用したことを特徴とする請求項1から7のいずれか一つに記載の裏込め注入材。   The backfilling injection material according to any one of claims 1 to 7, wherein an early strong cement is applied as the cement.
JP2007329250A 2007-12-20 2007-12-20 Backfill grouting material Pending JP2009150130A (en)

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CN102660952A (en) * 2012-05-30 2012-09-12 湖南宏禹水利水电岩土工程有限公司 Controllable clay paste slurry grouting technique
JP2013067536A (en) * 2011-09-22 2013-04-18 Sumitomo Osaka Cement Co Ltd Cement composition and method for manufacturing cement hardened body
CN103641363A (en) * 2013-12-06 2014-03-19 广州市鲁班建筑工程技术有限公司 Self-repaired vinylon polymer waterproof mortar additive and preparation method thereof
JP2016124760A (en) * 2015-01-05 2016-07-11 太平洋マテリアル株式会社 Non-dispersible underwater concrete composition and hardened body thereof, and method for producing non-dispersible underwater concrete
JP2018058724A (en) * 2016-10-05 2018-04-12 キザイテクト株式会社 Mortar kneaded product for filler, additive, and infilling-injecting-filling method
JP2020128316A (en) * 2019-02-08 2020-08-27 太平洋マテリアル株式会社 Construction method of tunnel lining concrete
CN112707683A (en) * 2019-12-24 2021-04-27 科之杰新材料集团福建有限公司 Sleeve grouting material for prefabricated part and preparation method thereof
CN115959849A (en) * 2022-06-14 2023-04-14 中建三局第二建设工程有限责任公司 Additive applied to muck, preparation method and use method thereof
CN116606108A (en) * 2023-05-17 2023-08-18 江河工程检验检测有限公司 High-performance backfill grouting material for TBM construction of water-rich tunnel section and preparation method thereof

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JP2005163526A (en) * 2003-11-13 2005-06-23 Fujita Corp Filler for rear face cavity of mountain tunnel and filling method for rear face cavity for mountain tunnel using the same
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JPH07291703A (en) * 1994-04-18 1995-11-07 Chichibu Onoda Cement Corp Backfillgrouting material
JPH11116305A (en) * 1997-10-06 1999-04-27 Asahi Chem Ind Co Ltd Cement modifying agent and resin mortar composition
JP2001019528A (en) * 1999-07-09 2001-01-23 Showa Mining Co Ltd Grout material composition, hardened product and application thereof
JP2004284844A (en) * 2003-03-20 2004-10-14 Daiichi Kasei Sangyo Kk Plastic lightweight grouting material, method of manufacturing the same and filling process for the same
JP2005163526A (en) * 2003-11-13 2005-06-23 Fujita Corp Filler for rear face cavity of mountain tunnel and filling method for rear face cavity for mountain tunnel using the same
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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013067536A (en) * 2011-09-22 2013-04-18 Sumitomo Osaka Cement Co Ltd Cement composition and method for manufacturing cement hardened body
CN102660952A (en) * 2012-05-30 2012-09-12 湖南宏禹水利水电岩土工程有限公司 Controllable clay paste slurry grouting technique
CN103641363A (en) * 2013-12-06 2014-03-19 广州市鲁班建筑工程技术有限公司 Self-repaired vinylon polymer waterproof mortar additive and preparation method thereof
CN103641363B (en) * 2013-12-06 2015-11-18 广州市鲁班建筑工程技术有限公司 A kind of selfreparing vinylon waterproof polymer mortar admixture and preparation method thereof
JP2016124760A (en) * 2015-01-05 2016-07-11 太平洋マテリアル株式会社 Non-dispersible underwater concrete composition and hardened body thereof, and method for producing non-dispersible underwater concrete
JP2018058724A (en) * 2016-10-05 2018-04-12 キザイテクト株式会社 Mortar kneaded product for filler, additive, and infilling-injecting-filling method
JP2020128316A (en) * 2019-02-08 2020-08-27 太平洋マテリアル株式会社 Construction method of tunnel lining concrete
JP7195962B2 (en) 2019-02-08 2022-12-26 太平洋マテリアル株式会社 Construction method of tunnel lining concrete
CN112707683A (en) * 2019-12-24 2021-04-27 科之杰新材料集团福建有限公司 Sleeve grouting material for prefabricated part and preparation method thereof
CN112707683B (en) * 2019-12-24 2022-05-10 科之杰新材料集团福建有限公司 Sleeve grouting material for prefabricated part and preparation method thereof
CN115959849A (en) * 2022-06-14 2023-04-14 中建三局第二建设工程有限责任公司 Additive applied to muck, preparation method and use method thereof
CN115959849B (en) * 2022-06-14 2024-03-26 中建三局第二建设工程有限责任公司 Additive applied to dregs, preparation method and use method thereof
CN116606108A (en) * 2023-05-17 2023-08-18 江河工程检验检测有限公司 High-performance backfill grouting material for TBM construction of water-rich tunnel section and preparation method thereof
CN116606108B (en) * 2023-05-17 2024-05-24 江河安澜工程咨询有限公司 High-performance backfill grouting material for TBM construction of water-rich tunnel section and preparation method thereof

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