JPH0481004B2 - - Google Patents
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- Publication number
- JPH0481004B2 JPH0481004B2 JP62169133A JP16913387A JPH0481004B2 JP H0481004 B2 JPH0481004 B2 JP H0481004B2 JP 62169133 A JP62169133 A JP 62169133A JP 16913387 A JP16913387 A JP 16913387A JP H0481004 B2 JPH0481004 B2 JP H0481004B2
- Authority
- JP
- Japan
- Prior art keywords
- retaining wall
- wall
- earth retaining
- earth
- ground
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
【発明の詳細な説明】
「産業上の利用分野」
本発明は、軟弱地盤での開削工事を行う際の山
留工法に係り、山留壁の内側を掘削する際、背面
土圧によつて山留壁が変形するのを防止するため
の山留工法に関する。[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a mountain retaining method for excavation work in soft ground, and when excavating the inside of a retaining wall, the back earth pressure This invention relates to a retaining construction method for preventing retaining walls from deforming.
「従来の技術」
従来のこの種の山留工法としては、第５図ない
し第７図に示すような、先行地中梁工法等が知ら
れている。"Prior Art" As this type of conventional mountain retaining construction method, the advance underground beam construction method as shown in FIGS. 5 to 7 is known.
ここで、先行地中梁工法をシールド立坑の築造
に適用した場合について説明する。まず、第５図
に示すように、地盤Ｇ中に深溝を掘削し、その内
部に鉄筋を配置するとともにコンクリートを打設
して地中連続壁を構築し、これを井筒状に形成し
て山留壁１を築造する。ついで、山留壁１内の地
盤Ｇの所定の深度に先行地中梁２，２を設けて局
部的に地盤を強固なものとし、開削時に支保工が
架設されるまで、山留壁１の変形を防止する役目
を持たせるとともに、盤ぶくれ、ヒービング等の
底面破壊を防止するようにしたものである。そし
て、先行地中梁２，２が施された後には、第６図
に示すように、山留壁１の内部を開削しながら山
留壁１の内側の所定の場所に地梁３を設置して行
く。その際、山留壁１は背面土圧によつて開削面
側に押されて変形しようとするが、先行地中梁
２，２が施されているため、山留壁１に大きな曲
げモーメントおよび山留壁の変形が発生するのを
防止するようになつている。第６図中、破線ａは
山留壁１に作用する曲げモーメントを示す曲線で
あり、第７図に示す先行地中梁２，２を施さない
場合の曲げモーメント曲線ｂに比べて低い値とな
る。 Here, we will explain the case where the advance underground beam method is applied to the construction of a shield shaft. First, as shown in Figure 5, a deep trench is excavated in the ground G, reinforcing bars are placed inside the trench, and concrete is poured to construct an underground continuous wall. Construct retaining wall 1. Next, advance underground beams 2, 2 are installed at a predetermined depth of the ground G within the retaining wall 1 to strengthen the ground locally, and the retaining wall 1 is maintained until the shoring is erected during excavation. It has the function of preventing deformation and also prevents damage to the bottom surface such as board bulging and heaving. After the preliminary underground beams 2, 2 have been installed, the ground beams 3 are installed at predetermined locations inside the retaining wall 1 while excavating the inside of the retaining wall 1, as shown in Figure 6. I'll go. At that time, the mountain retaining wall 1 is pushed toward the excavation surface by the back earth pressure and tries to deform, but because the preceding underground beams 2, 2 are installed, a large bending moment and a large bending moment are applied to the mountain retaining wall 1. This is designed to prevent the retaining wall from deforming. In Fig. 6, the broken line a is a curve showing the bending moment acting on the retaining wall 1, and it has a lower value than the bending moment curve b shown in Fig. 7 when the preceding underground beams 2, 2 are not installed. Become.
「発明が解決しようとする問題点」
ところが、前記従来の先行地中梁工法を用いた
土留工法においては、先行地中梁が山留壁を局部
的に水平方向へ押し広げる水平方向梁の役目しか
しておらず、背面土圧力に対して山留壁だけの強
度で支持するようになるとともに、連続地中壁工
法や柱列杭工法等の山留壁に対しては山留壁に応
力集中が発生することから、壁厚を厚くしたり内
部の鉄筋を太くしたりして山留壁の強度を上げる
ようにしており、その分施工費が高くなるという
問題点があつた。"Problems to be Solved by the Invention" However, in the above-mentioned conventional earth retaining method using the preceding underground beam construction method, the preceding underground beam plays the role of a horizontal beam that locally pushes the mountain retaining wall horizontally. However, the strength of the mountain retaining wall alone supports the back soil pressure, and stress concentrates on the mountain retaining wall for mountain retaining walls such as continuous underground wall construction method and column row pile construction method. Because of this, efforts were made to increase the strength of the retaining walls by increasing the thickness of the walls and thickening the reinforcing bars inside, which led to the problem of higher construction costs.
本発明は、前記問題点に鑑みてなされたもの
で、軟弱地盤の地盤改良を行うと同時に、山留壁
を補強し山留壁内の開削工事を行う際に、山留壁
が背面土圧によつて開削面側に変形したり、山留
壁に発生する曲げモーメントを低減させることの
できる山留工法を提供することを目的としてい
る。 The present invention has been made in view of the above-mentioned problems, and at the same time improves the soft ground and reinforces the mountain retaining wall. It is an object of the present invention to provide a retaining construction method that can reduce the bending moment that is generated in the retaining wall and deforms toward the cut surface side due to the retaining wall.
「問題点を解決するための手段」
本発明は、山留壁の開削壁面側に沿つて生石灰
杭の打設や薬液注入等を行つて地盤改良を施すこ
とにより、前記山留壁を開削面側から背面側に押
圧した状態で、山留壁の開削面側を掘削すること
により、前記問題点を解決するようにしている。"Means for Solving the Problems" The present invention improves the ground by driving quicklime piles or injecting chemicals along the cut-and-cut wall side of the mountain-retaining wall. The above-mentioned problem is solved by excavating the open cut side of the retaining wall while pressing from the side to the back side.
「実施例」
以下、本発明を第１図ないし第４図を参照しな
がら説明する。第１図ないし第３図は本発明の土
留工法の一実施例を示すものであり、地盤中に立
坑を築造する際に適用したものである。第１図は
地盤中に築造された土留壁付近の側断面図、第２
図はその平面図である。"Example" The present invention will be described below with reference to FIGS. 1 to 4. Figures 1 to 3 show an embodiment of the earth retaining method of the present invention, which is applied when constructing a shaft in the ground. Figure 1 is a side sectional view of the area near the earth retaining wall built in the ground, Figure 2
The figure is a plan view thereof.
第１図，第２図において、地盤Ｇ中には深溝を
掘削し、その内部に鉄筋籠を配置するとともも
に、内部にコンクリートを打設することにより連
続地中壁を築造し、これを井筒状に形成すること
により土留壁１０としたものである。そして、土
留壁１０の開削壁面１０ｆ側に、土留壁１０に沿
つて一定の距離をおいて、所定深度の生石灰杭１
１，１１，…を一定間隔毎に打設していく。そし
て、地盤Ｇ中に打設された生石灰が地盤Ｇ中で膨
張する際に、土留壁１０の開削壁面１０ｆ側に圧
力Ｆをかけ、土留壁１０を背面側に変形させると
ともに、第１図に示す符号ｃのように、土留壁１
０内を開削する際に背面土圧によつて生じる曲げ
モーメントと逆のモーメントを与えるようにして
いる。さらに、前記生石灰杭１１，１１，…は、
土留壁１０に平行に打設されているため、土留壁
１０を面状態で押圧することになり、土留壁１０
に局部的な応力集中を起こさせることなく、土留
壁１０を構造的に補強する構造物となるととも
に、地盤の受動圧を増加させ、根切り底の安定を
図るようにしている。 In Figures 1 and 2, a deep trench is excavated in the ground G, a reinforcing bar cage is placed inside the trench, and concrete is poured inside to construct a continuous underground wall. The earth retaining wall 10 is formed by forming it into a well shape. Then, a quicklime pile 1 of a predetermined depth is placed on the excavated wall surface 10f side of the earth retaining wall 10 at a certain distance along the earth retaining wall 10.
1, 11, ... are poured at regular intervals. When the quicklime placed in the ground G expands in the ground G, pressure F is applied to the excavated wall surface 10f side of the earth retaining wall 10, deforming the earth retaining wall 10 to the rear side, and as shown in FIG. As shown by the symbol c, retaining wall 1
When excavating inside 0, a moment opposite to the bending moment generated by back earth pressure is applied. Furthermore, the quicklime piles 11, 11,...
Since it is placed parallel to the earth retaining wall 10, the earth retaining wall 10 is pressed in a flat state, and the earth retaining wall 10
The structure structurally reinforces the earth retaining wall 10 without causing local stress concentration in the soil, and also increases the passive pressure of the ground and stabilizes the root cut bottom.
そして、土留壁１０の掘削予定面積側に圧縮力
を作用させた後には、土留壁１０の開削面側を掘
削するとともに、切梁２，２，…を所定の位置に
設置していく。この際、土留壁１０には背面土圧
が作用して曲げモーメントが生じ、開削面側に変
形しようとするが、生石灰杭１１，１１，…によ
つて与えられたプレロードによつて背面側へ変形
していた分だけ変形量が打ち消され、土留壁１０
に作用する曲げモーメントｄや土留壁１０の変位
量は、第３図に示すような状態となる。なお、第
４図には、地盤改良を行うことなく通常の開削を
行つた場合の土留壁１０の変位量と土留壁１０に
作用する曲げモーメントが示されており、前記第
３図に示す本発明の工法を用いたものより、開削
側へ大きな変形量と曲げモーメントｅとが発生し
ているのを確認することができる。 After applying a compressive force to the planned excavation area side of the earth retaining wall 10, the cut surface side of the earth retaining wall 10 is excavated, and the struts 2, 2, . . . are installed at predetermined positions. At this time, rear earth pressure acts on the earth retaining wall 10, causing a bending moment, and the wall tries to deform toward the cut surface side, but due to the preload given by the quicklime piles 11, 11,... The amount of deformation is canceled by the amount of deformation, and the retaining wall 10
The bending moment d acting on the earth retaining wall 10 and the amount of displacement of the retaining wall 10 are as shown in FIG. Furthermore, Fig. 4 shows the amount of displacement of the earth retaining wall 10 and the bending moment acting on the earth retaining wall 10 when normal excavation is performed without soil improvement. It can be confirmed that a larger amount of deformation and bending moment e were generated toward the cut-out side than when using the construction method of the invention.
ここで、本実施例の生石灰杭を用いて地盤改良
を行う場合に、土留壁１０に作用するプレロード
の算出方法について説明する。 Here, a method for calculating the preload acting on the retaining wall 10 when performing ground improvement using the quicklime pile of this embodiment will be described.
第２図において、Ｐ点の生石灰杭打設深度中央
の増加側圧（プレロード量）は、次の式(1)で示さ
れる。 In Fig. 2, the increasing lateral pressure (preload amount) at the center of the quicklime pile driving depth at point P is expressed by the following equation (1).
ｙ＝10.3x＋1.76……(1)
ここで、ｙ：増加側圧（ｔ／m2）
ｘ：１／（l1 2＋l2 2＋l3 2）
（l1，l2，l3は第２図における記号を示す。）
また、増加側圧は時間とともに減少し、これは
次の式(2)で示される。 y=10.3x+1.76...(1) Here, y: Increased lateral pressure (t/m 2 ) x: 1/(l 1 2 + l 2 2 + l 3 2 ) (l 1 , l 2 , l 3 are (Symbols in Figure 2 are shown.) Furthermore, the increased lateral pressure decreases with time, and this is shown by the following equation (2).
ｙ＝−0.02153x1＋0.8972x2＋2.2695……(2)
ここで、ｙ：ある時間経過後の増加側圧（ｔ／
m2）
x1：経過時間（分0.75）
x2：経過時間０の場合の増加側圧（ｔ／
m2）
12≦x1≦3000 13.1≦x2≦35.5
そして式(1)(2)は生石灰杭深度中央の増加側圧を
求めるものであり、これを基準深度fbとすれば、
深度方向分布は着目深度をfaとして、着目深度の
増加側圧は次の式(3)で示される。 y=-0.02153x 1 +0.8972x 2 +2.2695...(2) Here, y: Increased lateral pressure after a certain time (t/
m 2 ) x 1 : Elapsed time (min 0.75 ) x 2 : Increased side pressure when elapsed time is 0 (t/
m 2 ) 12≦x 1 ≦3000 13.1≦x 2 ≦35.5 Equations (1) and (2) calculate the increased lateral pressure at the center of the quicklime pile depth, and if this is taken as the reference depth fb,
For the depth direction distribution, the increasing lateral pressure with respect to the focused depth is expressed by the following equation (3), where fa is the focused depth.
ya＝yb×fa／fb……(3)
ここで、ya：着目深度の増加側圧（ｔ／m2）
yb：基準深度の増加側圧（ｔ／m2）
fa：着目深度
fb：基準深度
以上のように、式(1)，(2)，(3)を使用することに
より、生石灰杭の打設順序に合わせた増加側圧を
求めることができる。そして、増加側圧が求まれ
ば、プレロードの曲げモーメントと剪断力を知る
ことができる。 ya＝yb×fa／fb……(3) Here, ya: Increased lateral pressure at the depth of interest (t/m 2 ) yb: Increased lateral pressure at the reference depth (t/m 2 ) fa: Depth of interest fb: Above the reference depth By using equations (1), (2), and (3), it is possible to determine the increased lateral pressure according to the order of driving quicklime piles. Once the increased side pressure is determined, the preload bending moment and shear force can be determined.
なお、上記以外の他の実施例、あるいは技術的
事項について以下に述べる。 Note that other embodiments or technical matters other than those described above will be described below.
(i) 前記実施例においては、土留壁１０に圧力を
加える手段として生石灰杭１１を打設し、その膨
張力により、土留壁１０にプレロードを作用させ
るようにしたが、これに限られることなく、前記
生石灰杭の部分に高圧噴射等により薬液注入を行
うことにより、土留壁１０にプレロードを与える
ようにしてもよい。そして、杭の位置や数、また
注入圧等を調節することにより、土留壁に作用さ
せる圧力を任意に設定することができるのは、勿
論である。(i) In the above embodiment, quicklime piles 11 were driven as a means of applying pressure to the earth retaining wall 10, and the expansion force of the piles caused a preload to be applied to the earth retaining wall 10, but the present invention is not limited to this. A preload may be applied to the earth retaining wall 10 by injecting a chemical solution into the quicklime pile by high-pressure injection or the like. Of course, by adjusting the position and number of piles, injection pressure, etc., the pressure applied to the retaining wall can be set arbitrarily.
(ii) 前記実施例においては、土留壁に地中連続壁
を用いたが、これに限られることなく、例えば柱
列杭等、土留壁として用いられるものであればど
のようなものでもよい。(ii) In the above embodiment, an underground continuous wall was used as the earth retaining wall, but the present invention is not limited to this, and any type of wall that can be used as an earth retaining wall may be used, such as column piles.
このように、本発明の土留工法は、山留壁の掘
削壁面側に沿つて生石灰杭や薬液注入等を行つて
地盤改良を施すことにより、前記山留壁の掘削壁
面側にプレロードをかけ、土留壁に曲げモーメン
トを発生させて予め背面側に変形させようとした
ものであるので、土留壁の内部を開削する際に、
その分が打ち消されることとなり、土留壁が開削
面側に変形するのを低減させることができる。ま
た、本発明の杭による地盤改良は、土留壁に局部
的な集中応力を発生させることなく、土留壁の補
強構造物としての役目を果たすことになるため、
従来のものより壁厚を薄くしたり内部の鉄筋を細
くしたりして土留壁の強度を低減させることがで
き、その分施工費を低くすることができる。 As described above, the earth retaining method of the present invention improves the ground by applying quicklime piles, chemical injection, etc. along the excavated wall side of the mountain retaining wall, thereby applying a preload to the excavated wall side of the mountain retaining wall, This is an attempt to generate a bending moment in the earth retaining wall and deform it to the rear side in advance, so when excavating the inside of the earth retaining wall,
This amount is canceled out, and it is possible to reduce the deformation of the earth retaining wall toward the cut surface side. In addition, the ground improvement using the piles of the present invention serves as a reinforcing structure for the retaining wall without causing localized concentrated stress on the retaining wall.
The strength of the earth retaining wall can be reduced by making the walls thinner and the internal reinforcing bars thinner than conventional ones, and the construction cost can be reduced accordingly.
「発明の効果」
以上説明したように本発明は、山留壁の掘削壁
面側に沿つて生石灰杭を打設したり薬液注入等を
行つて地盤改良を施すことにより、前記山留壁の
掘削壁面側に圧力をかけて山留壁を背面側に押圧
した状態で、山留壁の掘削壁面側を開削するよう
にしたものであるので、土留壁の内部を開削する
際に、その分が打ち消されることとなり、土留壁
が開削壁面側に変形するのを低減させることがで
きるとともに、土留壁に局部的に集中応力を発生
させることなく、土留壁の補強構造物としての役
目を果たすことになるため、壁厚を薄くしたり内
部の鉄筋を細くしたりして土留壁の強度を低減さ
せることができることとなり、その分施工費を低
くすることができるという優れた効果を奏する。"Effects of the Invention" As explained above, the present invention improves the ground by driving quicklime piles along the excavated wall side of the mountain retaining wall, injecting chemicals, etc. The excavation wall side of the retaining wall is excavated while applying pressure to the wall side and pressing the retaining wall to the rear side, so when excavating the inside of the retaining wall, the This can reduce the deformation of the earth retaining wall toward the excavated wall surface, and it can also serve as a reinforcing structure for the earth retaining wall without causing localized concentrated stress on the earth retaining wall. Therefore, it is possible to reduce the strength of the earth retaining wall by reducing the wall thickness or making the internal reinforcing bars thinner, which has the excellent effect of reducing construction costs accordingly.
第１図ないし第３図は本発明の一実施例を示す
もので、第１図は地盤中に築造された土留壁の前
面側に生石灰杭による地盤改良を施した状態の土
留壁付近の側断面図、第２図は第１図の平面図、
第３図は土留壁の掘削面側を開削した状態の土留
壁付近の側断面図、第４図は地盤改良を施さない
場合に開削した状態の土留壁付近の側断面図、第
５図ないし第７図は従来の技術を示すものであ
り、第５図は先行地中梁工法を施し状態の土留壁
付近の側断面図、第６図は第５図の開削状態を示
す土留壁付近の側断面図、第７図は地盤改良を施
さないで開削している状態を示す土留壁付近の側
断面図である。
Ｇ……地盤、１０……土留壁（地中連続壁、柱
列杭）、１０ｆ……開削面、１１……生石灰杭、
薬液注入。
Figures 1 to 3 show one embodiment of the present invention, and Figure 1 shows the side near the earth retaining wall where the front side of the earth retaining wall constructed in the ground has been improved with quicklime piles. A sectional view, Figure 2 is a plan view of Figure 1,
Figure 3 is a side sectional view of the vicinity of the earth retaining wall with the excavated side of the earth retaining wall excavated, Figure 4 is a side sectional view of the vicinity of the earth retaining wall with the earth excavated without soil improvement, and Figures 5 to 5. Figure 7 shows the conventional technology, Figure 5 is a side sectional view of the vicinity of the earth retaining wall with the advanced underground beam construction method applied, and Figure 6 is a side sectional view of the vicinity of the earth retaining wall shown in Figure 5 in the excavation state. Side sectional view, Figure 7 is a side sectional view of the vicinity of the earth retaining wall, showing a state in which the excavation is carried out without soil improvement. G...Ground, 10...Earth retaining wall (underground continuous wall, column pile), 10f...Open cut surface, 11...Quicklime pile,
Chemical injection.
Claims (1)
や薬液注入等を行つて地盤改良を施すことによ
り、前記山留壁を開削面側から背面側に押圧した
状態で、山留壁の開削面側を掘削することを特徴
とする山留工法。1 By improving the ground by driving quicklime piles or injecting chemicals along the cut-cut wall side of the retaining wall, the retaining wall is pressed from the cut-cut side to the back side. A mountain retaining method characterized by excavating the open-cut side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16913387A JPS6414425A (en) | 1987-07-07 | 1987-07-07 | Landslide protection wall method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16913387A JPS6414425A (en) | 1987-07-07 | 1987-07-07 | Landslide protection wall method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6414425A JPS6414425A (en) | 1989-01-18 |
| JPH0481004B2 true JPH0481004B2 (en) | 1992-12-22 |
Family
ID=15880896
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16913387A Granted JPS6414425A (en) | 1987-07-07 | 1987-07-07 | Landslide protection wall method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6414425A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02225717A (en) * | 1989-02-27 | 1990-09-07 | Fudo Constr Co Ltd | Landslide protection using foundation pile |
| JP4915037B2 (en) * | 2001-08-02 | 2012-04-11 | 株式会社大林組 | Method for controlling the amount of deformation of the mountain wall |
| JP2012082676A (en) * | 2011-04-11 | 2012-04-26 | Takenaka Komuten Co Ltd | Displacement controlling method |
| JP6460713B2 (en) * | 2014-10-10 | 2019-01-30 | 株式会社竹中工務店 | Construction method of underground beam |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6013110A (en) * | 1983-07-04 | 1985-01-23 | Takenaka Komuten Co Ltd | Soil strut preloading work |
-
1987
- 1987-07-07 JP JP16913387A patent/JPS6414425A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6414425A (en) | 1989-01-18 |
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