JP2006002439A - Heaving prevention method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the uplifting (heaving) of an excavated surface by artesian water pressure in the case of underground excavation. <P>SOLUTION: A method preventing the uplifting (heaving) of the excavated ground surface is so constituted that the weight ground 1 substituting the ground of the upper part of the artesian water pressure acting surface for a substance with large mass is developed and that it is used as a resisting body higher than the artesian water pressure by using the same ground together with a ground anchor 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

この発明は、環境問題を引起すことなく経済的で安全な地下掘削工事の施工を提供する。 The present invention provides an economical and safe underground excavation work without causing environmental problems.

従来は、被圧地下水を汲み上げ同水位を下げて揚圧力を軽減する工法や、被圧地下水を含む層より下に土留壁を延伸し止水壁として同水圧を遮断する工法、また地盤改良をすることで同水圧の作用する面を下げて揚圧力を上回る土被りを確保する工法、等があるが、地盤沈下による環境問題や施工の信頼性と工事費の高額化など問題がある。 Conventional methods include pumping groundwater under pressure and lowering the water level to reduce the lifting pressure, extending the retaining wall below the layer containing the groundwater under pressure and blocking the water pressure as a water barrier, and improving the ground. However, there are methods such as lowering the surface on which the water pressure acts to secure a covering that exceeds the lifting pressure, but there are problems such as environmental problems due to land subsidence, reliability of construction and high construction costs.

本発明は、従来の工法に比べ環境問題を引起すことなく、確実な施工と工事費の軽減が可能な盤膨れ防止工事の実現を図る。   The present invention aims to realize a panel swelling prevention construction that can reliably perform construction and reduce construction costs without causing environmental problems as compared with conventional construction methods.

本発明は、被圧地下水圧の作用する不透水層から上部の地盤を同水圧を上回る質量の抵抗地盤とすることで、及び、実績と信頼性の高いグランドアンカーの抵抗力とを併用して、掘削地盤面を押上げる盤膨れを防止することを可能とした。   The present invention is to make the upper ground from the impermeable layer where the pressured groundwater pressure acts as the resistance ground of the mass exceeding the same water pressure, and in combination with the proven and reliable ground anchor resistance. It was possible to prevent the bulging of the board that pushed up the excavated ground surface.

本発明は、従来の工法に比べ安全な工事を提供し、かつ工事費の軽減を図ることが可能である。   The present invention can provide safer construction than conventional methods and can reduce construction costs.

本発明は、地下掘削時被圧地下水圧が不透水層より上部の地盤を押上げようとしたとき、質量の大きい物質にて造成された１重量地盤を含む抵抗地盤が、または同地盤と併用する３グランドアンカーの抵抗力が、被圧地下水圧に抵抗し掘削地盤面の***（盤膨れ）を防止する。
１重量地盤は、比重の異なる物質を同一容器内で攪拌すると、重力と浮力の働きにより比重の大きい物質が下部に比重の小さい物質が上部に堆積する。この現象を利用して質量の大きい置換材と地盤土砂との置換を可能とするものである。 In the present invention, when the ground pressure under pressure during underground excavation tries to push up the ground above the impermeable layer, the resistance ground including the one-weight ground formed of a material having a large mass is used together with the ground. The resistance force of the three ground anchors resists the pressure of groundwater under pressure and prevents the excavation ground surface from rising (swelling).
In the 1-weight ground, when substances having different specific gravity are stirred in the same container, substances having a large specific gravity are deposited on the lower part and substances having a small specific gravity are deposited on the upper part by the action of gravity and buoyancy. By using this phenomenon, it is possible to replace the replacement material having a large mass with the ground sediment.

１重量地盤は、アースオーガーにて施工し置換物質には鉄粒を使用する。施工機械は、バイブロ式地盤改良機や高圧噴射攪拌地盤改良機、大口径ボーリング機、多軸オーガーやベノト他各種地盤改良機械や場所打杭機械とすることも可能である。置換物質は鉄粉とすることも可能である。
３グランドアンカーはロータリーパーカッションにて施工し、受圧板はコンクリート二次製品を使用する。
本案は、掘削（掘削にかかわらず構造物設置）時等に掘削部土留壁（構造物壁）沿いの掘削面（受働抵抗）側下部に施工することで、受働抵抗を増大させ土留壁の根入長を低減（構造物の安定性を増加）することも可能である。
〔施工手順〕
１重量地盤は、置換しようとする区域下端まで減摩材を適度に地盤中に吐出しながら、オーガー正回転で削孔しオーガースクリューで地盤土砂を揚土する。
オーガー先端が基準深度に達したら減摩材を適度に混合した鉄粒を加圧吐出し、地盤土砂を鉄粒で押出すとともにオーガー正回転で攪拌し同スクリューで揚土しつつオーガーを引上げる。
置換しようとする区域上端までオーガー先端が達し所定の量の鉄粒が注入できたら、鉄粒の吐出を停止しオーガーを逆回転させ揚土していた土砂を圧密埋戻ししながら引上げる。
３グランドアンカーは支障のない深度まで掘削したところで施工し、受圧板は部分掘りして低く設置し地山はその後受圧板レベルまで掘削する。あらかじめ予定した余裕の範囲で受圧板をはずしさらに部分掘りして順次盛替え地山掘削をする。これらを所定の深度に達するまで繰返し掘削を完了する。
〔品質管理〕
１重量地盤施工中の管理は、置換材の供給量を管理するとともにオーガーのトルクを管理して、置換材が十分充填されたことを確認する。
１重量地盤施工後の管理は、あらかじめ地中応力測定用計器（間隙水圧計、土圧計、ひずみ計等）を埋設しておき、地中応力の増加状況を確認する。又ボーリングにて資料採取を行い確認するか、観測孔を設置し物理探査等（レーダー、弾性波、磁気、水平載荷等）を実施して確認する。
３グランドアンカーの管理は既定であるので省略する。 1 weight ground will be constructed by earth auger and iron particles will be used as replacement material. The construction machine can be a vibro-type ground improvement machine, a high-pressure jet agitating ground improvement machine, a large-diameter boring machine, a multi-axis auger, Benoto, and other various ground improvement machines and cast-in-place pile machines. The replacement substance may be iron powder.
3 The ground anchor will be constructed by rotary percussion, and the pressure receiving plate will be a concrete secondary product.
This plan increases the passive resistance by constructing the bottom of the excavation surface (passive resistance) side along the excavation part retaining wall (structure wall) during excavation (installation of structures regardless of excavation). It is also possible to reduce the insertion length (increase the stability of the structure).
[Construction procedure]
In the 1-weight ground, the anti-friction material is appropriately discharged into the ground at the lower end of the area to be replaced, and the ground is ground by the auger screw with the auger screw rotating.
When the tip of the auger reaches the reference depth, pressurize and discharge iron particles mixed with an appropriate amount of anti-friction material, extrude the ground earth and sand with iron particles and agitate the auger forward and pull up the auger while unloading with the same screw. .
When the tip of the auger reaches the upper end of the area to be replaced and a predetermined amount of iron particles can be injected, the discharge of the iron particles is stopped, the auger is rotated in the reverse direction, and the earth and sand that have been pumped up are pulled up while being consolidated backfilled.
3 Ground anchors will be constructed when excavated to a point where there is no hindrance, and the pressure plate will be partially dug and installed low, and the ground will then be excavated to the level of the pressure plate. Remove the pressure plate in the margin of the planned schedule and dig further and excavate the ground again. These are repeated until the predetermined depth is reached.
〔quality management〕
The management during the construction of 1 weight ground is to manage the supply amount of the replacement material and the torque of the auger to confirm that the replacement material is sufficiently filled.
For management after construction of 1-weight ground, underground stress measuring instruments (pore water pressure gauge, earth pressure gauge, strain gauge, etc.) are buried in advance to check the increase of underground stress. Also, collect data by boring and confirm, or install an observation hole and conduct physical exploration (radar, elastic wave, magnetism, horizontal loading, etc.).
Since management of 3 ground anchors is a default, it is omitted.

本案盤膨れ防止工法請求項１の施工姿図である。It is a construction figure of this plan board swelling prevention construction method claim 1. 本案盤膨れ防止工法請求項２の施工姿図である。It is a construction figure of this plan board swelling prevention construction method claim 2.

符号の説明Explanation of symbols

１重量地盤 ２土留壁 ３グランドアンカー
1 weight ground 2 retaining wall 3 ground anchor

Claims (2)

地下掘削時に、被圧地下水圧の作用による掘削地盤面の***に対して、同水圧作用面と掘削地盤面との間にある土塊＝抵抗地盤の一部の区域を、質量の大きい物質にて置換した１重量地盤を造成し、抵抗地盤の質量が被圧地下水圧を上回ることで掘削地盤面の***を防止する盤膨れ防止工法。 During underground excavation, against the uplift of the excavated ground surface due to the action of pressurized groundwater pressure, a part of the soil block = resistance ground between the hydrostatic surface and the excavated ground surface is made of a material with a large mass A bulge prevention construction method that prevents the digging ground surface from rising by creating a substituted 1 weight ground and the resistance ground mass exceeding the groundwater pressure. 請求項１に加え、被圧地下水圧作用面以深地盤に下部の耐荷体を、上部に掘削地盤面に接地した受圧板又は同面直下に埋設した耐荷体を、それぞれ鉛直に結合した３グランドアンカーを相当数設置し、同アンカーの引抜抵抗力と抵抗地盤の質量とを併用することで、被圧地下水圧に抵抗し掘削地盤面の***を防止する盤膨れ防止工法。
In addition to claim 1, a three-ground anchor in which a lower load-bearing body is connected to the ground deeper than the surface of the ground surface where the pressure is applied and a pressure-receiving plate grounded to the excavation ground surface or a load-bearing body buried directly below the ground is connected vertically. A bulge prevention construction method that resists pressured groundwater pressure and prevents the excavation ground surface from rising by using a considerable number of the joints and combining the pullout resistance of the anchor and the mass of the resistance ground.

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