JP4682944B2 - Composite grout water stop method around mine shaft - Google Patents

Composite grout water stop method around mine shaft Download PDF

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JP4682944B2
JP4682944B2 JP2006200273A JP2006200273A JP4682944B2 JP 4682944 B2 JP4682944 B2 JP 4682944B2 JP 2006200273 A JP2006200273 A JP 2006200273A JP 2006200273 A JP2006200273 A JP 2006200273A JP 4682944 B2 JP4682944 B2 JP 4682944B2
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tunnel
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泰宏 須山
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Kajima Corp
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本発明は、廃棄物の地層処分、特に原子力発電から生じる放射性廃棄物の地層処分において、地下深部の安定した地層中に廃棄体を埋設処分するために構築される処分坑道の周辺岩盤の止水工法に関するものである。   In the geological disposal of waste, particularly radioactive waste resulting from nuclear power generation, the water stoppage of the rock around the disposal tunnel constructed to bury the waste in a stable deep underground It relates to the construction method.

放射性廃棄物の地層処分は、「物質を閉じ込める力」を持っている地下深部の地層に、閉じ込め性をさらに確かなものとするため、工学的対策、例えば廃棄体の周りを水を透しにくいベントナイト等の粘土(緩衝材)で取り囲み、ステンレス鋼製のキャニスター内のガラス固化体から放射性物質が地下水に溶け出ても、水を透しにくい粘土の緩衝材が吸着し、その場所から放射性物質を移動しにくくする対策を施し、高レベル放射性廃棄物を埋設し、人間の生活環境から隔離する方法である。   The geological disposal of radioactive waste is an engineering measure, for example, it is difficult for water to permeate around the waste body in order to further secure the confinement property in the deep underground layer that has “power to confine materials” Surrounded by clay (buffer material) such as bentonite, even if radioactive material dissolves into the groundwater from the vitrified material in the stainless steel canister, the clay buffer material that is difficult to permeate water is adsorbed, and the radioactive material from that location This is a method of taking measures to make it difficult to move, embedding high-level radioactive waste, and isolating it from the human living environment.

図7は、地層処分場の一例のイメージ図であり、地下深部に多数本の処分坑道51からなる処分パネル50が複数配置されている。立坑や斜坑などのアクセス坑道52により廃棄体が搬入される。図8は、処分坑道51における廃棄体定置方法の一例(横置き方式)であり、廃棄体Aの周囲のベントナイト緩衝材などの人工バリアBと岩盤の天然バリアCとの多重バリアシステムにより、安全性が確保されている。人工バリアBの役目は、廃棄体Aから天然バリアCへの核種放出率の低減であり、天然バリアCの役目は、生物圏への核種移行遅延である。   FIG. 7 is an image diagram of an example of a geological disposal site, in which a plurality of disposal panels 50 including a large number of disposal tunnels 51 are arranged in the deep underground. Waste is carried in through an access tunnel 52 such as a vertical shaft or an inclined shaft. FIG. 8 shows an example of a method for placing waste in the disposal mine 51 (horizontal placement method), and the safety is achieved by a multi-barrier system including an artificial barrier B such as bentonite cushioning material around the waste A and a natural barrier C of the rock mass. Is secured. The role of the artificial barrier B is to reduce the release rate of the nuclide from the waste A to the natural barrier C, and the role of the natural barrier C is to delay the nuclide migration to the biosphere.

このような地層処分において、地下に坑道(立坑、斜坑や水平坑道など)を掘削すると、湧水が生じる。湧水量が増加すると、空洞の安定性の維持や湧水の排水が困難になるため、通常はグラウトが行われる。グラウト材料としては強度や長期安定性の点で信頼性の高いセメントを主体とした非薬液系が選定される。   In such geological disposal, springs are generated when excavating tunnels (vertical shafts, inclined shafts, horizontal shafts, etc.) underground. Grouting is usually done because increasing the amount of spring water makes it difficult to maintain cavity stability and drain the spring water. As the grout material, a non-chemical solution based mainly on cement having high reliability in terms of strength and long-term stability is selected.

注入されたグラウト材(セメント)が地下水に接すると、地下水のpHは12.5から13程度の高アルカリに変化する。通常の土木工事では特に問題とならないが、高レベル放射性廃棄物地層処分の分野では、この高アルカリの地下水が緩衝材(人工バリア)や周辺岩盤(天然バリア)を変質させ、高レベル放射性廃棄物地層処分において必要な人工バリアと天然バリアの機能を損なうことが想定される。   When the injected grout material (cement) comes into contact with the groundwater, the pH of the groundwater changes to a high alkali of about 12.5 to 13. Although there is no particular problem with ordinary civil engineering work, in the field of geological disposal of high-level radioactive waste, this highly alkaline groundwater alters the buffer material (artificial barrier) and surrounding rock (natural barrier), resulting in high-level radioactive waste. It is assumed that the function of the artificial barrier and the natural barrier necessary for geological disposal will be impaired.

そのため、現在、低pHセメントの開発が進められているが(例えば、特許文献1参照)、低pHセメントは硬化速度が遅いため、グラウト材料としては不適切である。湧水を止めるためにグラウト材には速硬性が求められている。また、粘土グラウト(天然材料のため人工バリアや天然バリアの機能を損なわない)も対象としては考えられているが、硬化せず目詰まりのみに期待する材料であるため、湧水に対するグラウト材料としては低pHセメントと同様に不適切である。   For this reason, development of low pH cement is currently underway (see, for example, Patent Document 1), but low pH cement is unsuitable as a grout material because of its slow curing rate. In order to stop spring water, grout materials are required to be fast-curing. In addition, clay grout (a natural material that does not impair the function of an artificial barrier or a natural barrier) is also considered as a target, but it is a material that does not harden and is expected only for clogging, so as a grout material for spring water Is not as suitable as low pH cement.

上記したように、材料および施工方法の観点から、現状では、高レベル放射性廃棄物地層処分を対象とした湧水に対する具体的な対処方法が無い。   As described above, from the viewpoint of materials and construction methods, there is currently no specific method for dealing with spring water intended for geological disposal of high-level radioactive waste.

なお、本発明に関連する湧水対策として、例えば特許文献2〜5に記載された発明がある。特許文献2の発明は、山岳トンネル掘削における凍結法による地盤改良方法であり、本トンネルに先行して作業用シールドトンネルを本トンネルの掘削部に沿って構築し、作業用シールドトンネルの内部より改良地盤内に凍結管を埋設し、掘削部の全周域を凍結固化し、トンネルの形成深度に影響されることなく効率的かつ確実に行えるようにしたものである。   In addition, there exists the invention described in patent documents 2-5 as a spring countermeasure with respect to this invention, for example. The invention of Patent Document 2 is a ground improvement method by freezing method in mountain tunnel excavation. A work shield tunnel is constructed along the excavation part of this tunnel prior to this tunnel, and is improved from the inside of the work shield tunnel. A freezing pipe is buried in the ground, and the entire circumference of the excavation part is frozen and solidified so that it can be efficiently and reliably performed without being affected by the tunnel formation depth.

特許文献3の発明は、山岳トンネル掘削における凍結法による地盤改良方法であり、薬液の注入により、本トンネルの掘削部を囲繞する形態に止水領域を形成した後、前記止水領域の内側の前記掘削部に沿った部分を凍結させ、地下流水が存在するような場合でも、冷熱エネルギーが逸散することなく、確実かつ効率的な凍結がなされるようにしたものである。   The invention of Patent Document 3 is a ground improvement method by a freezing method in mountain tunnel excavation. After a water stop area is formed in a form surrounding the excavation part of the tunnel by injection of a chemical solution, an inner side of the water stop area is formed. The part along the excavation part is frozen, and even when groundwater exists, the freezing energy is not dissipated and the freezing is surely and efficiently performed.

特許文献4の発明は、軟弱地盤や湧水の多い地盤等のトンネル掘削工法であり、凍結管による凍結工法に代えて、トンネルの切羽部分に液化ガスの冷気を吹き付け、当該切羽部分の地山を凍らせながらトンネルの掘削作業を行うものである。   The invention of Patent Document 4 is a tunnel excavation method for soft ground or ground with a lot of spring water. Instead of the freezing method using a freezing pipe, cold air of liquefied gas is blown to the face of the tunnel, and the ground of the face is The tunnel excavation work is performed while freezing.

特許文献5の発明は、山岳トンネルのトンネル先受け工法において、湧水性地盤を含む地山であっても、湧水対策を兼ねた施工を行うものであり、トンネル掘削領域の上方に先受け工として、非湧水性地盤には有孔鋼管が、湧水性地盤には凍結管が配置されるように既設トンネル先端部から打設し、有孔鋼管からは注入材を地山に注入して改良体を造成し、凍結管では地盤を凍結させて凍土を形成し、これらをトンネル上方にアーチ状に形成するものである。   The invention of Patent Document 5 is a tunnel tip receiving method for mountain tunnels, which performs construction that also serves as a countermeasure against spring water, even in the case of a natural ground that includes spring ground, and is located above the tunnel excavation area. As for the perforated steel pipe, the perforated steel pipe is placed at the tip of the existing tunnel so that the frozen pipe is placed on the springy ground, and the injected material is injected into the ground from the perforated steel pipe for improvement. In the freezing pipe, the ground is frozen to form frozen soil, and these are formed in an arch shape above the tunnel.

特許第2941269号公報Japanese Patent No. 2941269 特開平3−13688号公報JP-A-3-13688 特開平3−13690号公報JP-A-3-13690 特開平10−18755号公報Japanese Patent Laid-Open No. 10-18755 特開2005−344460号公報JP 2005-344460 A

前述したように、地層処分における湧水対策には、グラウト材料として強度や長期安定性の点で信頼性の高いセメントを主体とした非薬液系が選定され、また、高レベル放射性廃棄物地層処分の分野では、この高アルカリの地下水が緩衝材(人工バリア)や周辺岩盤(天然バリア)を変質させ、高レベル放射性廃棄物地層処分において必要な人工バリアと天然バリアの機能を損なうことが想定されるため、グラウト材として低pHセメントが望まれているが、低pHセメントは硬化速度が遅く、湧水を止めることができない。   As mentioned above, non-chemical liquid systems mainly composed of cement, which is highly reliable in terms of strength and long-term stability, are selected as countermeasures for spring water in geological disposal, and geological disposal of high-level radioactive waste. In this field, it is assumed that this highly alkaline groundwater alters the buffer material (artificial barrier) and the surrounding rock mass (natural barrier) and impairs the function of the artificial barrier and natural barrier required for high-level radioactive waste geological disposal. Therefore, low pH cement is desired as a grout material, but low pH cement has a slow curing rate and cannot stop spring water.

また、前述した先行技術文献等の凍結工法による湧水対策は、坑道への湧水を一時的に止められても、強度や長期安定性が要求される地層処分のグラウト材料として用いることはできない。   Moreover, the spring measures by the freezing method described in the prior art documents mentioned above cannot be used as a grout material for geological disposal that requires strength and long-term stability even if the spring water to the tunnel is temporarily stopped. .

本発明は、上記課題を解決すべくなされたもので、放射性廃棄物等の地層処分において、硬化速度が遅いが、緩衝材や周辺岩盤を変質させない低pHセメント等の非薬液系グラウト材料を用いた信頼性の高い止水が可能となる坑道周辺複合グラウト止水工法を提供することにある。   The present invention has been made to solve the above-mentioned problems, and uses a non-chemical grouting material such as low-pH cement that has a slow curing speed but does not alter the buffer material and surrounding rock mass in geological disposal of radioactive waste and the like. The purpose of this invention is to provide a grouting water stop construction method around a mine that enables highly reliable water stoppage.

本発明の請求項1に係る発明は、掘削された坑道への湧水を防止する坑道周辺の止水工法であり、坑道周辺(坑道切羽や坑道周囲)近傍を凍結工法により凍結させて坑道への湧水を止めた後、前記凍結領域周囲の外側領域に低pHの非薬液系グラウト材料を注入し、前記凍結領域が融解した後、当該凍結領域の坑道周囲に低pHの非薬液系グラウト材料を注入することを特徴とする坑道周辺複合グラウト止水工法である。   The invention according to claim 1 of the present invention is a waterproofing method around a mine that prevents spring water from being excavated, and the vicinity of a mine (around a tunnel face or around a mine) is frozen by a freezing method to the mine. After stopping the spring water, the low pH non-chemical liquid grout material is injected into the outer area around the frozen area, and after the frozen area is melted, the low pH non-chemical liquid grout is formed around the tunnel in the frozen area. It is a composite grouting water stop method around the tunnel characterized by injecting material.

本発明における低pHの非薬液系グラウト材料とは、主として、低アルカリ(pHが12.5から13程度の高アルカリよりpHが低いもの)で、セメントを主体とした非薬液系すなわちセメント系(セメントミルク、セメントモルタル、セメントベントナイト等)のグラウト材料(低pHセメント系グラウト材料)をいう。一例として、硬化速度の遅い所謂低pHセメントが用いられる。このようなセメント系以外でも、低pHで非薬液系のグラウト材料であれば、用いることができる。   The low-pH non-chemical liquid grout material in the present invention is mainly a low alkali (pH lower than a high alkali having a pH of about 12.5 to 13), and a non-chemical liquid system based on cement, ie, cement-based (cement milk) , Cement mortar, cement bentonite, etc.) grout material (low pH cement grout material). As an example, so-called low pH cement having a low curing rate is used. Other than the cement type, any non-chemical solution grout material having a low pH can be used.

本発明では、例えば図1〜図3に示すように、硬化速度の遅い低pHセメント等でも硬化できるように、凍結工法を用いて一時的に坑道周辺近傍の湧水を止める(坑道への地下水流動を止める)。凍結領域周囲の外側領域に低pHセメント等を注入し硬化させる。一時的な坑道周辺近傍の止水に、地質環境特性に与える影響が不明確な硬化速度が速い薬液系(水ガラス系と高分子系)や非薬液系での急硬材の添加の代わりに、凍結工法(凍結管や冷気吹付け等)を採用する。例えば図4に示すように、凍結工法を用いて一時的に湧水を止めた箇所(凍結領域の坑道周囲)にも、融解後(自然融解や強制融解)、低pHセメント等を用いて坑道周囲近傍を硬化させる。   In the present invention, for example, as shown in FIGS. 1 to 3, the spring near the tunnel is temporarily stopped using a freezing method so that it can be cured even with a low pH cement or the like having a low curing rate (groundwater to the tunnel). Stop the flow). Low pH cement or the like is injected into the outer region around the frozen region and cured. As an alternative to adding quick hardening materials in the chemical system (water glass system and polymer system) or non-chemical system that has a fast curing speed and has an unclear effect on the geological environment characteristics, in the temporary water stop around the tunnel. Adopt a freezing method (freezing pipe, cold air blowing, etc.). For example, as shown in FIG. 4, even at a place where the spring water is temporarily stopped using the freezing method (around the freezing area tunnel), after melting (natural melting or forced melting), a tunnel using low pH cement or the like Harden the surrounding area.

本発明の請求項2に係る発明は、請求項1に記載の坑道周辺複合グラウト止水工法において、凍結領域は、坑道切羽とその坑道周囲近傍であることを特徴とする坑道周辺複合グラウト止水工法である。   The invention according to claim 2 of the present invention is the tunnel surrounding composite grouting water stop construction method according to claim 1, wherein the frozen region is a pit face and the vicinity of the mine shaft surrounding pit. It is a construction method.

これは、図2に示すように、坑道切羽において湧水が生じた場合であり、トンネル掘削機の組込凍結管・補助凍結管などを用いて坑道切羽とその坑道周囲近傍(切羽外周部分)を凍結させる。図3に示すように、凍結領域周囲の外側領域に低pHセメント等を注入し硬化させ、融解後、図4に示すように、凍結領域の坑道周囲(切羽外周部分)に低pHセメント等を注入し硬化させる。止水範囲は、湧水箇所や湧水圧などにより決定する。なお、本発明は基本的に切羽部や坑道周辺から湧水が生じた場合に適用されるが、湧水発生前に適用することを排除するものではなく、また全面改良すべき箇所があれば連続的に適用することもある。   This is a case where spring water is generated at the tunnel face as shown in FIG. 2. Using the built-in freezing pipe and auxiliary freezing pipe of the tunnel excavator, the tunnel face and the vicinity of the tunnel (outer periphery of the face) Freeze. As shown in FIG. 3, low pH cement or the like is injected into the outer region around the frozen region and cured, and after melting, as shown in FIG. Inject and cure. The water stop range is determined by the spring location and spring pressure. In addition, the present invention is basically applied when spring water is generated from the face part or the vicinity of the tunnel, but it does not exclude application before the occurrence of spring water, and if there is a place to be improved entirely. Sometimes applied continuously.

本発明の請求項3に係る発明は、請求項1に記載の坑道周辺複合グラウト止水工法において、凍結領域は、坑道切羽における坑道周囲近傍の凍結を繰り返すことにより坑道軸方向に沿って連続して形成されていることを特徴とする坑道周辺複合グラウト止水工法である。   The invention according to claim 3 of the present invention is the tunnel surrounding composite grouting water stop construction method according to claim 1, wherein the freezing region is continuous along the shaft axis direction by repeating freezing in the vicinity of the tunnel at the tunnel face. It is a grouting water stop construction method around a mine shaft characterized by being formed by

これは、図5に示すように、対象領域が全体的に高透水の場合であり、前述した切羽部分での止水(凍結工とグラウト工)を坑道軸方向に沿って連続的に繰り返すことにより、坑道周囲の外側に低pHセメント等を用いたグラウト領域、内側に融解後の低pHセメント等を用いたグラウト領域を連続的に形成する。坑道周囲の透水性を低下させることができる。   As shown in FIG. 5, this is a case where the entire target area has high water permeability, and the water stoppage (freezing work and grouting work) at the face portion described above is continuously repeated along the tunnel axis direction. Thus, a grout region using low pH cement or the like is continuously formed on the outer periphery of the tunnel, and a grout region using low pH cement or the like after melting is continuously formed on the inner side. The water permeability around the tunnel can be reduced.

本発明の請求項4に係る発明は、請求項2又は請求項3に記載の坑道周辺複合グラウト止水工法において、坑道切羽より後方の位置の坑道内から坑道切羽における凍結領域の外側領域に向けて注入孔を削孔し、凍結領域の外側領域に低pHの非薬液系グラウト材料を注入することを特徴とする坑道周辺複合グラウト止水工法である。   The invention according to claim 4 of the present invention is the tunnel peripheral composite grouting water stop construction method according to claim 2 or claim 3, and is directed from the inside of the tunnel at a position behind the tunnel face to the outside area of the frozen area at the tunnel face. This is a composite grouting water stop method around a mine shaft, characterized in that the injection hole is drilled and a non-chemical liquid grout material having a low pH is injected into the outer region of the freezing region.

これは、図3に示すように、凍結領域を削孔することなく、凍結領域の外側領域にグラウトを行う場合であり、坑道内から注入孔を傾斜させ凍結領域を避けて削孔することにより、凍結領域に水みちが形成されるのが防止される。   This is a case where grouting is performed in the outer region of the frozen region without drilling the frozen region, as shown in FIG. 3, and the injection hole is inclined from inside the tunnel to avoid the frozen region. The formation of a water channel in the frozen region is prevented.

以上のような本発明においては、
(1)凍結工法を用いることにより、一時的に坑道周辺の湧水を止めることができ、坑道への湧水を止めることで、坑道周辺の地下水流動を抑制でき、硬化速度の遅い低pHセメント等を用いても十分に硬化させ、止水することが可能となる。
In the present invention as described above,
(1) By using the freezing method, it is possible to temporarily stop the spring water around the tunnel, and by stopping the spring water to the tunnel, the groundwater flow around the tunnel can be suppressed, and the low pH cement with a slow hardening rate. Even if it uses etc., it can fully harden and can stop water.

(2)坑道周辺近傍の凍結領域が融解しても、その外側領域の低pHセメント等を用いたグラウトにより地下水流動が抑制されているため、坑道周囲近傍にも硬化速度の遅い低pHセメント等を用いて止水することができる。 (2) Even if the frozen area near the tunnel is thawed, the groundwater flow is suppressed by the grout using the low pH cement, etc. in the outer area. Can be used to stop the water.

(3)凍結工法を用いることにより、一時的な止水に、地質環境特性に与える影響が不明確な硬化速度が速い薬液系(水ガラス系と高分子系)や非薬液系の急硬材を用いないで済むと共に、一時的な止水の時間調整が可能となる。 (3) By using the freezing method, temporary hard water, fast-curing chemicals (water glass and polymer) and non-chemical rapid hardeners that have unclear effects on geological environmental characteristics It is possible to temporarily adjust the water stoppage time.

(4)坑道周辺を低pHセメント等を用いて連続的に止水し、透水性を低下させることにより、高レベル放射性廃棄物地層処分で核種の移行経路と考えられているゆるみ域の遮断が併せて可能となる。 (4) By blocking water continuously around the tunnel using low pH cement, etc., and reducing water permeability, it is possible to block loose areas that are considered to be nuclide migration routes in geological disposal of high-level radioactive waste. It is also possible.

なお、本発明で用いる低pHセメントは、pHが12.5よりも小さく、緩衝材や周辺岩盤を変質させない性能を有するものであればよい。また、本発明は、特に高レベル放射性廃棄物の地層処分に有効に適用されが、その他の廃棄物の地層処分にも適用することができる。   In addition, the low pH cement used in the present invention is not particularly limited as long as the pH is lower than 12.5 and has a performance that does not alter the buffer material and the surrounding rock mass. In addition, the present invention is particularly effectively applied to geological disposal of high-level radioactive waste, but can also be applied to geological disposal of other wastes.

本発明は、以上のような構成からなるので、次のような効果が得られる。
(1)凍結工法を用いて一時的に坑道周辺の湧水を止め、その外側に低pHセメントをグラウトし、融解後の凍結領域にも低pHセメント等の非薬液系グラウト材料をグラウトするため、硬化速度が遅いが、緩衝材や周辺岩盤を変質させない低pHセメント等の非薬液系グラウト材料を用いた信頼性の高い止水が可能となる。
Since the present invention is configured as described above, the following effects can be obtained.
(1) To temporarily stop spring water around the tunnel using a freezing method, grout low pH cement on the outside, and grout non-chemical liquid grout materials such as low pH cement in the frozen region after thawing Highly reliable water stop using a non-chemical liquid grout material such as low pH cement that does not alter the buffer material and the surrounding rock mass, although the curing speed is slow.

(2)高レベル放射性廃棄物地層処分においては、本発明の低pHセメント等の非薬液系グラウトを坑道軸方向に連続させることにより、核種の移行経路と考えられているゆるみ域の遮断も併せて可能となる。 (2) In geological disposal of high-level radioactive waste, non-chemical grouting such as the low-pH cement of the present invention is continued in the axial direction of the tunnel to cut off the slack zone that is considered to be a nuclide migration route. Is possible.

以下、本発明を図示する実施の形態に基づいて説明する。この実施形態は、高レベル放射性廃棄物の地層処分に適用した例である。図1は、本発明で用いる坑道切羽での凍結工法の一例を示す鉛直断面図である。図2は、本発明の坑道切羽での凍結工法の止水範囲を示す水平断面図である。図3は、本発明の凍結後の低pHセメントを用いたグラウト範囲を示す水平断面図である。図4は、本発明の融解後の低pHセメントを用いたグラウト範囲を示す水平断面図である。   Hereinafter, the present invention will be described based on the illustrated embodiment. This embodiment is an example applied to the geological disposal of high-level radioactive waste. FIG. 1 is a vertical sectional view showing an example of a freezing method at a tunnel face used in the present invention. FIG. 2 is a horizontal sectional view showing the water stoppage range of the freezing method at the tunnel face of the present invention. FIG. 3 is a horizontal sectional view showing a grout range using the low pH cement after freezing according to the present invention. FIG. 4 is a horizontal sectional view showing the grout range using the low pH cement after melting according to the present invention.

図1、図2に示すように、地下深部の安定した岩盤の天然バリアC内にシールド機10により坑道1が掘削され、湧水を有する亀裂Kにより坑道切羽において湧水が生じた場合、切羽とその坑道周囲近傍を凍結工法により凍結させ、凍結領域2により、一時的に坑道周辺近傍の湧水を止め、坑道1への地下水流動を止める。   As shown in FIG. 1 and FIG. 2, when the tunnel 1 is excavated by the shield machine 10 in the natural barrier C of the stable rock in the deep underground, and the spring is generated by the crack K having spring water, And the vicinity of the mine shaft is frozen by a freezing method, and the freezing region 2 temporarily stops the spring water in the vicinity of the mine shaft and stops the groundwater flow to the mine shaft 1.

図1に示すように、シールド機10の組込凍結管11により切羽部分2aを凍結させ、坑道周辺に差し込んだ補助凍結管12により坑道周囲近傍の切羽外周部分2bを凍結させる。図2に示すように、切羽前面の切羽部分2aとその外周におけるリング状の切羽外周部分2bにより凍結領域2が形成される。その止水範囲は、亀裂Kによる湧水箇所や湧水圧などにより決定される。また、補助凍結管12を埋め込むために用いた削孔は、適切な埋め戻し材で埋め戻し、水みちが形成されないようにする。   As shown in FIG. 1, the face part 2a is frozen by the built-in freezing pipe 11 of the shield machine 10, and the face outer peripheral part 2b in the vicinity of the roadway is frozen by the auxiliary freezing pipe 12 inserted around the roadway. As shown in FIG. 2, a frozen region 2 is formed by the face portion 2a on the front face of the face and the ring-shaped face outer periphery portion 2b on the outer periphery thereof. The water stoppage range is determined by the spring location and spring pressure due to the crack K. Moreover, the hole used for embedding the auxiliary freezing pipe 12 is backfilled with an appropriate backfilling material so that no water channel is formed.

凍結工法による止水が終了した後、図3に示すように、凍結領域2の周囲の外側領域に低pHセメントを注入し硬化させ、凍結領域2を覆うリング状の低pHセメントグラウト外側領域3を形成する。このグラウト外側領域3の坑道軸方向の長さは、凍結領域2の切羽外周部分2bを完全に覆うようにするのが好ましい。   After the water stoppage by the freezing method is completed, as shown in FIG. 3, the low pH cement is injected into the outer region around the freezing region 2 and hardened, and the ring-shaped low pH cement grout outer region 3 covering the freezing region 2. Form. The length of the grouting outer region 3 in the mine shaft axial direction preferably covers the face outer peripheral portion 2b of the freezing region 2 completely.

このグラウト外側領域3へのグラウト注入は、凍結領域2に水みちが形成されないように、切羽より後方(坑口側)の位置の坑道1内から切羽におけるグラウト外側領域3に向けて注入孔13を広がるように傾斜させて削孔し、グラウト外側領域3に低pHセメントを注入する。   The grout injection into the outer region 3 of the grout is performed such that the water hole is not formed in the freezing region 2 and the injection hole 13 is directed from the inside of the tunnel 1 at the rear side (wellhead side) to the outer region 3 of the face. The hole is inclined so as to expand, and low pH cement is injected into the outer grout region 3.

凍結領域2が融解した後、図4に示すように、その凍結領域2の坑道周囲の切羽外周部分2bに低pHセメントを注入し硬化させる。リング状の低pHセメントグラウト外側領域3の内側に、坑道1を覆うリング状の低pHセメントグラウト内側領域4が形成される。これにより、硬化速度が遅いが、緩衝材や周辺地盤を変質させない低pHセメントを用いたグラウト領域3、4により信頼性の高い止水がなされる。   After the frozen region 2 is melted, as shown in FIG. 4, the low pH cement is injected into the outer peripheral portion 2 b of the face around the tunnel of the frozen region 2 and hardened. A ring-shaped low pH cement grout inner region 4 that covers the mine shaft 1 is formed inside the ring-shaped low pH cement grout outer region 3. Thereby, although the hardening rate is slow, the water is cut off with high reliability by the grout regions 3 and 4 using the low pH cement which does not alter the buffer material and the surrounding ground.

凍結領域2は、自然融解を基本とするが、強制融解でもよい。強制融解の場合、凍結管を融解管として用いることもできる。低pHセメントグラウト外側領域3の低pHセメントグラウトが硬化して十分な止水効果が得られた段階で、凍結領域2が融解するように設定される。   The freezing region 2 is based on natural thawing, but may be forced thawing. In the case of forced thawing, a freezing tube can also be used as a thawing tube. When the low pH cement grout in the low pH cement grout outer region 3 is hardened and a sufficient water stop effect is obtained, the frozen region 2 is set to melt.

次に、図5は、対象領域が全体的に高透水の場合のグラウト範囲の例を示す水平断面図である。この場合も、坑道周囲近傍の凍結領域2の周囲に凍結領域2を覆う坑道軸方向に連続した低pHセメントグラウト外側領域3が形成され、凍結領域2に坑道軸方向に連続した低pHセメントグラウト内側領域4が形成される。前述した切羽部分での図1〜図4に示す凍結工とグラウト工を坑道軸方向に沿って連続的に繰り返すことにより、図5に示すグラウト領域を連続的に形成することができる。坑道周囲の透水性を低下させることができる。   Next, FIG. 5 is a horizontal sectional view showing an example of the grout range when the target region is entirely highly permeable. Also in this case, a low pH cement grout outer region 3 continuous in the mine shaft direction covering the freezing region 2 is formed around the freezing region 2 near the mine shaft periphery, and the low pH cement grout continuous in the mine shaft direction is formed in the freezing region 2. An inner region 4 is formed. The freezing process and the grouting process shown in FIGS. 1 to 4 at the face portion described above are continuously repeated along the shaft direction of the tunnel, whereby the grouting region shown in FIG. 5 can be formed continuously. The water permeability around the tunnel can be reduced.

このような連続したグラウト領域は、図6に示すような、核種の移行経路と考えられているゆるみ域の止水に適用することができる。高レベル放射性廃棄物地層処分においては、地下深部に掘削された処分坑道1内に廃棄体Aが横置きで配置され、ベントナイト緩衝材などの人工バリアBで埋め戻される。処分坑道1の周囲には、掘削によりゆるみ域Yが形成される。このゆるみ域Yに図5の連続したグラウト領域3、4で止水することにより、核種の移行経路と考えられているゆるみ域Yを遮断することができる。   Such a continuous grout region can be applied to water stoppage in a slack region considered as a nuclide migration path as shown in FIG. In the high-level radioactive waste geological disposal, the waste A is horizontally disposed in the disposal mine 1 excavated in the deep underground, and is backfilled with an artificial barrier B such as bentonite buffer material. A slack area Y is formed around the disposal mine 1 by excavation. By stopping the water in the slack area Y in the continuous grout areas 3 and 4 in FIG. 5, the slack area Y considered as a nuclide migration path can be cut off.

なお、以上は放射性廃棄物の地層処分に適用した場合について説明したが、その他の廃棄物の地層処分の坑道周辺の止水にも適用することができる。   In addition, although the above demonstrated the case where it applied to the geological disposal of a radioactive waste, it can apply also to the water stop of the mine shaft of other geological disposal of a waste.

本発明で用いる坑道切羽での凍結工法の一例を示す鉛直断面図である。It is a vertical sectional view showing an example of a freezing method at a tunnel face used in the present invention. 本発明の坑道切羽での凍結工法の止水範囲を示す水平断面図である。It is a horizontal sectional view which shows the water stop range of the freezing method in the tunnel face of this invention. 本発明の凍結後の低pHセメントを用いたグラウト範囲を示す水平断面図である。It is a horizontal sectional view which shows the grout range using the low pH cement after freezing of this invention. 本発明の融解後の低pHセメントを用いたグラウト範囲を示す水平断面図である。It is a horizontal sectional view which shows the grout range using the low-pH cement after melting of the present invention. 本発明の対象領域が全体的に高透水の場合のグラウト範囲の例を示す水平断面図である。It is a horizontal sectional view showing an example of a grout range when the target region of the present invention is entirely highly permeable. 核種の移行経路と考えられているゆるみ域を示す鉛直断面図である。It is a vertical sectional view showing a slack area considered as a nuclide migration path. 高レベル放射性廃棄物地層処分場の一例を示す部分断面斜視図である。It is a fragmentary sectional perspective view which shows an example of a high level radioactive waste geological disposal site. 高レベル放射性廃棄物の地層処分における廃棄体の定置方式の一例を示す部分断面斜視図である。It is a fragmentary sectional perspective view which shows an example of the placement method of the waste body in the geological disposal of a high level radioactive waste.

符号の説明Explanation of symbols

A…廃棄体
B…人工バリア(ベントナイト緩衝材)
C…天然バリア(岩盤)
K…湧水を有する亀裂
Y…ゆるみ域
1…坑道(処分坑道)
2…凍結領域
2a…切羽部分
2b…切羽外周部分
3…低pHセメントグラウト外側領域
4…低pHセメントグラウト内側領域
10…シールド機
11…組込凍結管
12…補助凍結管
13…注入孔
A ... Waste B ... Artificial barrier (bentonite cushioning material)
C ... Natural barrier (bedrock)
K ... Crack with spring water Y ... Loose area 1 ... Tunnel (disposal tunnel)
DESCRIPTION OF SYMBOLS 2 ... Freezing area | region 2a ... Face part 2b ... Face outer peripheral part 3 ... Low pH cement grout outer side area 4 ... Low pH cement grout inner side area 10 ... Shield machine 11 ... Built-in freezing pipe 12 ... Auxiliary freezing pipe 13 ... Injection hole

Claims (4)

掘削された坑道への湧水を防止する坑道周辺の止水工法であり、
坑道周辺近傍を凍結工法により凍結させて坑道への湧水を止めた後、前記凍結領域周囲の外側領域に低pHの非薬液系グラウト材料を注入し、前記凍結領域が融解した後、当該凍結領域の坑道周囲に低pHの非薬液系グラウト材料を注入することを特徴とする坑道周辺複合グラウト止水工法。
It is a water stop method around the mine that prevents spring water from being excavated,
After the vicinity of the tunnel is frozen by a freezing method and the spring water to the tunnel is stopped, a low pH non-chemical liquid grout material is injected into the outer area around the frozen area, and after the frozen area is thawed, the freezing A compound grouting water stop method around a mine shaft, characterized by injecting a low-pH non-chemical grouting material around the mine shaft in the area.
請求項1に記載の坑道周辺複合グラウト止水工法において、凍結領域は、坑道切羽とその坑道周囲近傍であることを特徴とする坑道周辺複合グラウト止水工法。   2. The tunnel peripheral composite grout waterstop method according to claim 1, wherein the frozen region is a tunnel face and the vicinity of the tunnel. 請求項1に記載の坑道周辺複合グラウト止水工法において、凍結領域は、坑道切羽における坑道周囲近傍の凍結を繰り返すことにより坑道軸方向に沿って連続して形成されていることを特徴とする坑道周辺複合グラウト止水工法。   The tunnel surrounding composite grout waterstop method according to claim 1, wherein the frozen region is formed continuously along the axis of the tunnel by repeatedly freezing the vicinity of the tunnel in the tunnel face. Peripheral composite grout water stop method. 請求項2又は請求項3に記載の坑道周辺複合グラウト止水工法において、坑道切羽より後方の位置の坑道内から坑道切羽における凍結領域の外側領域に向けて注入孔を削孔し、凍結領域の外側領域に低pHの非薬液系グラウト材料を注入することを特徴とする坑道周辺複合グラウト止水工法。
In the tunnel surrounding composite grouting water stop method according to claim 2 or claim 3, the injection hole is drilled from the inside of the tunnel at a position behind the tunnel face to the outside area of the frozen area in the tunnel face, A composite grouting water stop method around a mine shaft, characterized by injecting a non-chemical liquid grouting material having a low pH into the outer region.
JP2006200273A 2006-07-24 2006-07-24 Composite grout water stop method around mine shaft Expired - Fee Related JP4682944B2 (en)

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