JPS63142115A - Prevention work for liquefaction of ground - Google Patents
Prevention work for liquefaction of groundInfo
- Publication number
- JPS63142115A JPS63142115A JP28893186A JP28893186A JPS63142115A JP S63142115 A JPS63142115 A JP S63142115A JP 28893186 A JP28893186 A JP 28893186A JP 28893186 A JP28893186 A JP 28893186A JP S63142115 A JPS63142115 A JP S63142115A
- Authority
- JP
- Japan
- Prior art keywords
- ground
- improved
- unimproved
- water
- wall
- 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.)
- Granted
Links
- 230000002265 prevention Effects 0.000 title claims description 5
- 238000000034 method Methods 0.000 claims abstract description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 25
- 238000005056 compaction Methods 0.000 abstract description 5
- 239000004576 sand Substances 0.000 abstract description 4
- 238000002347 injection Methods 0.000 abstract description 2
- 239000007924 injection Substances 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 abstract description 2
- 229920002554 vinyl polymer Polymers 0.000 abstract description 2
- 239000011440 grout Substances 0.000 abstract 1
- 239000011800 void material Substances 0.000 abstract 1
- 239000011148 porous material Substances 0.000 description 13
- 238000010276 construction Methods 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 5
- 239000002689 soil Substances 0.000 description 4
- 230000006378 damage Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005206 flow analysis Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、砂質地盤等が液状化をするのを防止する地盤
の液状化防止工法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for preventing liquefaction of sandy ground or the like.
（従来技術）
水で飽和された低密度の砂質地盤は、地震による繰返し
せん断力を受けると、土粒子間に存在する間隙水の圧力
が急激に上昇し、地盤のせん断強度が低下する。これを
砂質地盤の液状化という。(Prior Art) When low-density sandy ground saturated with water is subjected to repeated shear forces due to earthquakes, the pressure of pore water existing between soil particles increases rapidly, and the shear strength of the ground decreases. This is called liquefaction of sandy ground.
この液状化によって地盤の破壊、構造物の破壊、転倒、
不等沈下などの被害が生じることは多くの地Ｂで報告さ
れている。この液状化対策工法としては、砂杭を立てる
サンドコンパクション工法、Ｓ肋ｎに棒をとりつけて突
き刺すバイブロフローテーション工法等の地盤の密度増
加工法と、砕石状を地中に立てるグラベルドレーン工法
、透水性のバイブを地中に埋めるドレーンパイプ工法な
どの過剰間隙水圧の早期消散を目的とする工法がある。This liquefaction causes ground destruction, structure destruction, overturning,
It has been reported that damage such as uneven subsidence occurs in many areas B. Methods to prevent liquefaction include sand compaction method in which sand piles are erected, vibroflotation method in which sticks are attached to S ribs to increase the density of the ground, gravel drain method in which crushed stones are erected underground, and water permeability method. There are construction methods that aim to quickly dissipate excess pore water pressure, such as the drain pipe construction method that buries a sex vibrator underground.
（発明が解決しようとする問題点）
しかし、これらの工法によって改良された液状化対策範
囲については、的確な設計手法が確立されてなく、現状
では各研究機関で検討している段階である。また、対策
を施した効果が実際の地震によって検証された例はない
。従って、構造物周辺の液状化対策範囲は過大となり易
く、経済的と言い難い問題がある。(Problems to be Solved by the Invention) However, no accurate design method has been established for the range of liquefaction countermeasures improved by these construction methods, and currently each research institution is currently investigating the issue. Furthermore, there is no example in which the effectiveness of countermeasures has been verified through actual earthquakes. Therefore, the range of liquefaction countermeasures around the structure tends to be excessive, which poses a problem that cannot be called economical.
更に、既設構造物には耐震設計されていないものも多々
あり、また、締め固め工法は施工時の振動・騒音の問題
がある。Furthermore, many existing structures are not designed to withstand earthquakes, and the compaction method has problems with vibration and noise during construction.
第６図は、改良地盤（締固め地盤）１と未改良地盤（緩
詰め地盤）２を用いた伝動実験結果及びその解析結果で
ある。回申の０内の数字は実験結果で、最大過剰間隙水
圧比（ΔＵ１％３Ｘ ／δｖ−）を示している。また、
改良地盤１内の曲線は、浸透流解析を実施した場合の過
ＩＪ ＩＩ隙水圧比分布である。なお、Δ（Ｊ ｗａｘ
は最大過剰間隙水圧、δＶ′は有効上被り重」である。Figure 6 shows the results of power transmission experiments using improved ground (compacted ground) 1 and unimproved ground (loosely packed ground) 2, and the results of their analysis. The numbers within 0 are experimental results and indicate the maximum excess pore water pressure ratio (ΔU1%3X/δv−). Also,
The curve in the improved ground 1 is the IJ II pore water pressure ratio distribution when a seepage flow analysis is performed. In addition, Δ(J wax
is the maximum excess pore water pressure and δV' is the effective overburden.
このような模型ｉｏ実験から、締め固め工法等で改良し
た砂質の改良地盤１は、地震によって周辺の緩い砂質の
未改良地盤２が液状化した場合、両地？Ａ１．２の過剰
ＷＡ隙水圧差によって改良地盤側に浸透水が流入し、液
状化した未改良の地盤２に隣接する改良地盤１の過剰間
隙水圧が上昇して地盤のせん断強度が低下するという問
題があることが判明した。From these model IO experiments, it has been found that if the sandy improved ground 1 that has been improved by compaction method etc. is liquefied in the surrounding loose sandy unimproved ground 2 due to an earthquake, will it be affected by both soils? Due to the excess WA pore water pressure difference in A1.2, seepage water flows into the improved ground side, and the excess pore water pressure in the improved ground 1 adjacent to the liquefied unimproved ground 2 increases, reducing the shear strength of the ground. It turned out there was a problem.
本発明の目的は、改良地盤の過剰間隙水圧の上昇を防止
できる地盤の液状化防止工法を提供することにある。An object of the present invention is to provide a ground liquefaction prevention method that can prevent an increase in excessive pore water pressure in improved ground.
（問題点を解決するための手段）
上記の目的を解決するため、本発明に係る地盤の液状化
防止工法は、改良地盤と未改良地盤との境界に不透水壁
を設けることを特徴とするものである。(Means for solving the problem) In order to solve the above object, the ground liquefaction prevention method according to the present invention is characterized by providing an impermeable wall at the boundary between the improved ground and the unimproved ground. It is something.
（作用）
この発明による不透水壁は、未改良地盤で該地盤の液状
化が発生してこの未改良地盤と改良地盤の過剰間隙水圧
差が大きくなっても、未改良地盤から改良地盤への浸透
水の流入を阻止する。従って、改良地盤で過剰＠陸水圧
が上昇するのを防止する。(Function) The impermeable wall according to the present invention can prevent the unimproved ground from becoming an improved ground even if liquefaction occurs in the unimproved ground and the excess pore water pressure difference between the unimproved ground and the improved ground becomes large. Prevents infiltration of water. Therefore, excessive @land water pressure is prevented from increasing in the improved ground.
（実施例）
以下水１ｉ ｕ）５の実論例を図面を参照して詳細に説
明する。第１因及び第２図は本発明を適用して防波堤を
構築する例を示したものである。まず、第２図に示すよ
うに支持地盤３の上の緩い砂層からなる未改良地！ｉ！
２の両側に２重の不透水壁４を設ける。この不透水壁４
は、薄肉の矢板、コンクリート製の連続地中壁、薬液注
入やビニール等による不透水膜などで形成する。不透水
壁４の下端は支持地盤３で支持させ、上端は必要に応じ
て隣接相区間を連結具５で連結する。次に、両側を不透
水壁４で区画された区間の未改良地盤２を、第１図に示
すよ０うに締め固め工法等で改良地盤１に改良する。(Example) Hereinafter, a practical example of water 1i u) 5 will be explained in detail with reference to the drawings. The first factor and FIG. 2 show an example of constructing a breakwater by applying the present invention. First, as shown in Figure 2, unimproved land consists of a loose sand layer on top of supporting ground 3! i!
A double impermeable wall 4 is provided on both sides of the wall 2. This impermeable wall 4
They are constructed using thin sheet piles, continuous underground walls made of concrete, and impermeable membranes made of chemical injection or vinyl. The lower end of the impermeable wall 4 is supported by the supporting ground 3, and the upper end is connected to adjacent phase sections by a connector 5 as required. Next, the unimproved ground 2 in the section partitioned by impermeable walls 4 on both sides is improved to improved ground 1 by compaction method etc. as shown in FIG.
次いで、改良地盤１の上にマウンド６を構築し、その上
に防波堤７を構築する。Next, a mound 6 is constructed on the improved ground 1, and a breakwater 7 is constructed thereon.
第３図は本発明を通用して埋立護岸を構築する例を示し
たものである。即ち、支持地盤３上の未改良地盤２にお
ける水域１０に沿った所定の区間の両側に不透水壁４を
設け、この不透水壁４で区画された区域内の地盤を改良
して改良地盤１を形成し、水Ｉ４１０に隣接した改良地
盤１上にマウンド６を構築し、その上にケーソン（又は
擁壁）９を設置する。FIG. 3 shows an example of constructing a reclaimed seawall using the present invention. That is, impermeable walls 4 are provided on both sides of a predetermined section of unimproved ground 2 on supporting ground 3 along water area 10, and the ground within the area divided by impermeable walls 4 is improved to create improved ground 1. A mound 6 is constructed on the improved ground 1 adjacent to the water I410, and a caisson (or retaining wall) 9 is installed on top of the mound 6.
第４図は本発明を適用して既設ａｍ物の周辺に構造物を
新規に建設する場合の液状化対策を示したものである。FIG. 4 shows measures against liquefaction when a new structure is constructed around an existing AM structure by applying the present invention.
即ち、支持地盤３上の未改良地盤２に抗１１を打ち、こ
れを支持体として既設構造物１２が建設されている場所
に隣接して構造物を建設する場合には、該既設構造物１
２が建設されている未改良ｊ１す盤２とそれに隣接する
ｌ！股予定未改良地盤との境界に不透水壁４を設け、か
かる状態でｌ！設予定未改良地盤の地盤改良を胞して改
良地盤１を形成し、その上に盛土１３を施す。That is, when constructing a structure adjacent to a place where an existing structure 12 is constructed by using resistors 11 as supports by driving resistors 11 into the unimproved ground 2 on the supporting soil 3, the existing structure 1
2 is being constructed on unimproved j1 board 2 and its adjacent l! An impermeable wall 4 is installed at the boundary with the planned unimproved ground, and in such a state l! Improved ground 1 is formed by improving the unimproved ground scheduled for construction, and embankment 13 is applied on top of the improved ground 1.
このようにすると、地震時に発生する未改良地盤２と改
良地Ｉ１１との間の過剰間隙水圧の不平衡を不透水壁４
によって遮断でき、新規構造物を安定に保つことができ
る。In this way, the unbalance of excess pore water pressure between the unimproved ground 2 and the improved ground I11 that occurs during an earthquake can be reduced by the impermeable wall 4.
can be shut off by the system, and the new structure can be kept stable.
第５図は改良地盤（締固め地盤）１と未改良地盤（緩詰
め地盤）２との境界に不透水壁４を設けた際の振動実験
結果を示したものである。図中（）内の数字は最大過剰
間隙水圧比（ΔｊｌｌａＸ／δＶ′）を示している。FIG. 5 shows the results of a vibration experiment when an impervious wall 4 was provided at the boundary between the improved ground (compacted ground) 1 and the unimproved ground (loosely packed ground) 2. In the figure, the numbers in parentheses indicate the maximum excess pore water pressure ratio (ΔjllaX/δV').
（発明の効果）
以上説明したように本発明に係る地盤の液状化防止工法
では、改良地盤と未改良地盤との境界に不透水壁をける
ので、地震時に未改良地盤内で急激に上昇する過剰間隙
水圧と改良地盤の過剰間隙水圧の圧力差によって生じる
改良地盤側への浸透水の流入を′ａｌＩｉでき、改良地
盤のせん断強度の低下を防止することができる。また、
本発明によれば、既存の改良地盤の補強も行うことがで
きる。(Effects of the Invention) As explained above, in the ground liquefaction prevention method according to the present invention, an impermeable wall is built at the boundary between the improved ground and the unimproved ground, so that rapid rises within the unimproved ground during an earthquake occur. The inflow of seepage water into the improved ground side caused by the pressure difference between the excess pore water pressure and the excess pore water pressure of the improved ground can be prevented, and a decrease in the shear strength of the improved ground can be prevented. Also,
According to the present invention, existing improved ground can also be reinforced.
更に本発明によれば、既設構造物が存在する未改良地盤
に隣接した地盤の改良を、既設構造物に影響なく行うこ
とができる。Furthermore, according to the present invention, it is possible to improve the ground adjacent to the unimproved ground where an existing structure exists without affecting the existing structure.
第１図は本発明を適用して成形された改良地盤上に防波
堤を構築する例の縦断面図、第２図は防波堤を構築する
予定地の未改良地盤の改良過程を示した縦断面図、第３
図は本発明を適用して酸形成された改良地盤上の埋立護
岸を構築する例の縦断面図、第４図は既設構造物に隣接
した未改良地盤を改良する例の縦断面図、第５図は本発
明の工法の効果を確認する振動実験結果を示す隣接地盤
の断面図、第６図は従来の工法の効果を確認する振動実
験結果を示す隣接地盤の断面図である。
１・・・改良地盤、２・・・未改良地盤、４・・・不透
水壁。
特 許 出 願 人 五洋建設株式会社第５図
第６図
第１図
第３図
第２図
上
第４図Fig. 1 is a longitudinal cross-sectional view of an example of constructing a breakwater on improved ground formed by applying the present invention, and Fig. 2 is a longitudinal cross-sectional view showing the improvement process of unimproved ground at the site where the breakwater is planned to be constructed. , 3rd
Figure 4 is a longitudinal cross-sectional view of an example of applying the present invention to construct a reclaimed revetment on improved soil formed with acid, Figure 4 is a longitudinal cross-sectional view of an example of improving unimproved ground adjacent to an existing structure, Figure 5 is a sectional view of the adjacent ground showing the results of a vibration experiment to confirm the effects of the construction method of the present invention, and Figure 6 is a sectional view of the adjacent ground showing the results of a vibration experiment to confirm the effects of the conventional construction method. 1...improved ground, 2...unimproved ground, 4...impermeable wall. Patent applicant Pentayo Construction Co., Ltd. Figure 5 Figure 6 Figure 1 Figure 3 Figure 2 Upper Figure 4
Claims (1)
を特徴とする地盤の液状化防止工法。A ground liquefaction prevention method characterized by installing an impermeable wall at the boundary between improved and unimproved ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61288931A JPH0645929B2 (en) | 1986-12-05 | 1986-12-05 | Ground liquefaction prevention method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61288931A JPH0645929B2 (en) | 1986-12-05 | 1986-12-05 | Ground liquefaction prevention method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63142115A true JPS63142115A (en) | 1988-06-14 |
| JPH0645929B2 JPH0645929B2 (en) | 1994-06-15 |
Family
ID=17736661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61288931A Expired - Lifetime JPH0645929B2 (en) | 1986-12-05 | 1986-12-05 | Ground liquefaction prevention method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0645929B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006070503A (en) * | 2004-08-31 | 2006-03-16 | Sato Kogyo Co Ltd | Blasting compaction method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4982632B2 (en) * | 2006-07-11 | 2012-07-25 | 独立行政法人港湾空港技術研究所 | Liquefaction countermeasure method under breakwater |
| JP4982631B2 (en) * | 2006-07-11 | 2012-07-25 | 独立行政法人港湾空港技術研究所 | Liquefaction countermeasure method under breakwater by underground wall construction |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58138816A (en) * | 1982-02-10 | 1983-08-17 | Hasegawa Komuten Co Ltd | Inprovement work for soft ground |
| JPS5988524A (en) * | 1982-11-08 | 1984-05-22 | Kiyotatsu Sasa | Method and apparatus for prevention of liquefaction of sandy ground |
-
1986
- 1986-12-05 JP JP61288931A patent/JPH0645929B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58138816A (en) * | 1982-02-10 | 1983-08-17 | Hasegawa Komuten Co Ltd | Inprovement work for soft ground |
| JPS5988524A (en) * | 1982-11-08 | 1984-05-22 | Kiyotatsu Sasa | Method and apparatus for prevention of liquefaction of sandy ground |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006070503A (en) * | 2004-08-31 | 2006-03-16 | Sato Kogyo Co Ltd | Blasting compaction method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0645929B2 (en) | 1994-06-15 |
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