JP2777626B2 - Ground liquefaction prevention method - Google Patents
Ground liquefaction prevention methodInfo
- Publication number
- JP2777626B2 JP2777626B2 JP25288990A JP25288990A JP2777626B2 JP 2777626 B2 JP2777626 B2 JP 2777626B2 JP 25288990 A JP25288990 A JP 25288990A JP 25288990 A JP25288990 A JP 25288990A JP 2777626 B2 JP2777626 B2 JP 2777626B2
- Authority
- JP
- Japan
- Prior art keywords
- aquifer
- water
- ground
- groundwater
- well
- 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 - Fee Related
Links
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Foundations (AREA)
Description
【発明の詳細な説明】 「産業上の利用分野」 本発明は、地盤の液状化を防止するための方法に関す
るものである。The present invention relates to a method for preventing ground liquefaction.
「従来の技術およびその課題」 周知のように、地震時に地盤が液状化して構造物が浮
き上がったり沈下したりする災害が発生している。地盤
の液状化を防止するためには地下水位を低く保持するこ
とが有効であり、したがって、液状化防止対策として地
下水を常時汲み揚げることで地下水位を常に十分に低く
保持しておく方法が広く採用されている。しかしなが
ら、その場合には、揚水ポンプの運転費、維持管理費が
かさむことは勿論のこと、汲み揚げた地下水の処理が必
要であり、しかも、周辺の井戸が枯渇したり地盤沈下を
招く恐れもある。"Conventional technology and its problems" As is well known, disasters occur in which the ground liquefies during an earthquake and structures rise or sink. In order to prevent liquefaction of the ground, it is effective to keep the groundwater level low.Therefore, as a countermeasure against liquefaction, there is a widespread method of keeping the groundwater level low by always pumping the groundwater. Has been adopted. However, in such a case, the operation and maintenance costs of the pump are increased, and it is necessary to treat the groundwater that has been pumped.In addition, the surrounding wells may be depleted or land subsidence may occur. is there.
本発明は上記の事情に鑑みてなされたもので、地下水
を汲み揚げることなく地下水位を低下せしめて、地盤の
液状化を有効に防止し得る方法を提供することを目的と
する。The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method capable of effectively preventing ground liquefaction by lowering a groundwater level without pumping groundwater.
「課題を解決するための手段」 本発明は、不透水層の上下に上部帯水層と下部帯水層
とが存する地盤の液状化を防止するための方法であっ
て、前記地盤に設ける構造物の周囲に地表から前記不透
水層に達する止水壁を設けるとともに、その止水壁の内
側に前記不透水層を貫通する井戸を設けて上部帯水層中
の地下水をその井戸を通して下部帯水層に導くことによ
り、前記止水壁の内側における上部帯水層中の地下水位
を低下せしめることを特徴とするものである。"Means for Solving the Problems" The present invention is a method for preventing liquefaction of the ground where an upper aquifer and a lower aquifer exist above and below an impermeable layer, and a structure provided on the ground A water blocking wall that reaches the water-impermeable layer from the surface of the ground is provided around the object, and a well that penetrates the water-impermeable layer is provided inside the water-tight wall, and groundwater in the upper aquifer is passed through the well to the lower zone. By leading to the water layer, the groundwater level in the upper aquifer inside the water stop wall is lowered.
「作用」 不透水層の上下に上部帯水層および下部帯水層が存す
るような地盤においては、下部帯水層の地下水位（間隙
水の水位）が上部帯水層の地下水位に比して低いことが
通常である。したがって、構築するべき構造物の周囲に
止水壁を設けてその止水壁の外部から地下水の流入を阻
止した上で、止水壁の内側に不透水層を貫通する井戸を
設けると、双方の帯水層の水位差によって上部帯水層中
の地下水が自ずと井戸を通って下部帯水層に流出するこ
とになる。したがって、止水壁の内側における上部帯水
層中の地下水位が下部帯水層の地下水位の位置まで低下
し、その結果、止水壁の内側における地盤の液状化が防
止される。"Action" In the ground where the upper and lower aquifers exist above and below the impermeable layer, the groundwater level of the lower aquifer (the level of the pore water) is lower than that of the upper aquifer. It is usually low. Therefore, when a water blocking wall is provided around the structure to be constructed to prevent the inflow of groundwater from outside the water blocking wall, and a well penetrating the water-impermeable layer inside the water blocking wall is provided. The groundwater in the upper aquifer naturally flows through the well to the lower aquifer due to the difference in water level between the aquifers. Therefore, the groundwater level in the upper aquifer inside the water stop wall drops to the position of the groundwater level in the lower aquifer, and as a result, liquefaction of the ground inside the water stop wall is prevented.
「実施例」 以下、本発明の一実施例を第１図および第２図を参照
して説明する。Embodiment An embodiment of the present invention will be described below with reference to FIG. 1 and FIG.
第１図は地盤１上に建築物２が設けられた状態を示す
立断面図、第２図はその平面図である。上記地盤１は、
粘土層等の不透水層３の上部に沖積砂層や埋立層等の液
状化を生じる恐れのある上部帯水層４が存在し、不透水
層３の下部には洪積層や砂れき層等の下部帯水層５が存
するものとなっている。そして、通常のように上部帯水
層４の地下水位WL1地表近くにあり、下部帯水層５の地
下水位WL2（間隙水の水位）はそれより低く不透水層３
付近にある。FIG. 1 is an elevational sectional view showing a state in which a building 2 is provided on a ground 1, and FIG. 2 is a plan view thereof. The ground 1 is
Above the water-impermeable layer 3 such as a clay layer, there is an upper aquifer 4 that may cause liquefaction such as an alluvial sand layer or a landfill layer. The aquifer 5 exists. Then, there is the groundwater level WL 1 near surface of the upper aquifer 4 in the usual manner, groundwater level WL 2 (pore water level) of the lower aquifer 5 is lower than that impermeable layer 3
Nearby.
また、上記建築物２は抗６により支持されて地盤１上
に設けられている。この建物物２の周囲の地盤１中には
上記不透水層３に達する止水壁７が設けられており、止
水壁７の外部から内側への地下水の流入が阻止されるよ
うになっている。The building 2 is supported on the ground 6 and provided on the ground 1. In the ground 1 around the building 2, a water blocking wall 7 reaching the water-impermeable layer 3 is provided, so that inflow of groundwater from outside to inside of the water blocking wall 7 is prevented. I have.
そして、止水壁７の内面と建築物２の外壁との間には
井戸８が設けられている。この井戸８は不透水層３を貫
通して設けられていて、上部帯水層４中に位置する上部
ストレーナ９と、下部帯水層５中に位置する下部ストレ
ーナ10とを有するものである。A well 8 is provided between the inner surface of the water blocking wall 7 and the outer wall of the building 2. The well 8 is provided penetrating the impermeable layer 3 and has an upper strainer 9 located in the upper aquifer 4 and a lower strainer 10 located in the lower aquifer 5.
上記のように、建築物２の周囲に不透水層３に達する
止水壁７を設けるとともに、止水壁７の内側に不透水層
３を貫通する井戸８を設けたことにより、上部帯水層４
の地下水位W1と下部帯水層５の地下水位WT2の水位差に
より、上部帯水層４中の地下水は自ずと井戸８を通って
下部帯水層５中に流出し、したがって、止水壁７の内側
における地下水位は、上部帯水層４の当初の地下水位WL
1の位置から下部帯水層５の地下水位WL2の位置まで低下
することになり、その結果、止水壁７の内側における地
盤１の液状化が防止されて建築物２の浮き上がりや沈下
を防止できるものである。As described above, the water blocking wall 7 that reaches the water impervious layer 3 is provided around the building 2 and the well 8 that penetrates the water impervious layer 3 is provided inside the water blocking wall 7, so that the upper aquifer is formed. Layer 4
The water level difference between the water table WT 2 groundwater level W 1 and the lower aquifer 5, groundwater upper aquifer 4 flows out into the lower aquifer in 5 naturally through the well 8, therefore, water stop The groundwater level inside the wall 7 is the initial groundwater level WL of the upper aquifer 4
As a result, the ground 1 is lowered from the position 1 to the position of the groundwater level WL 2 of the lower aquifer 5, and as a result, the liquefaction of the ground 1 inside the water blocking wall 7 is prevented, and the rising and sinking of the building 2 is prevented. It can be prevented.
そして、この場合には、動力が一切不要であるので地
下水を常時汲み揚げて地下水位を低く保持する場合のよ
うに運転費や保守費がかさんでしまうことはないし、止
水壁７の外側では上部帯水層４の地下水位WL1は低下す
ることがないので周辺地区における井戸枯渇や地盤沈下
を招く恐れはない。In this case, no power is required, so that the operation and maintenance costs do not increase as in the case where the groundwater is constantly pumped and the groundwater level is kept low. in no lead to well depletion and subsidence in the peripheral area since no groundwater level WL 1 of the upper aquifer 4 is reduced.
なお、必要であれば、第３図に示すように井戸８内に
ポンプ11を設けて、上部ストレーナ９から流入した上部
帯水層４中の地下水を下部ストレーナ10から下部帯水層
５中に圧送するようにしても良い。If necessary, a pump 11 is provided in the well 8 as shown in FIG. 3, and groundwater in the upper aquifer 4 flowing from the upper strainer 9 is transferred from the lower strainer 10 to the lower aquifer 5. You may make it feed by pressure.
また、本発明は、上記実施例のような建築物２を構築
する場合に適用するのみならず、たとえば第４図および
第５図に示すような共同溝等の地中構造物20を構築する
場合にも全く同様に適用できることはいうまでもない。In addition, the present invention is applied not only to the case where the building 2 is constructed as in the above-described embodiment, but also to construct an underground structure 20 such as a common ditch as shown in FIGS. 4 and 5, for example. Needless to say, the same can be applied to the case.
「発明の効果」 以上で詳細に説明したように、本発明は、地盤に設け
る構造物の周囲に地表から不透水層に達する止水壁を設
けるとともに、その止水壁の内側に不透水層を貫通する
井戸を設けて上部帯水層中の地下水をその井戸を通して
下部帯水層に導くものであるから、地下水を汲み揚げる
ことなく止水壁の内側における地下水位を低下せしめる
ことができ、その結果、止水壁の内側での地盤の液状化
を有効に防止し得るとともに、従来のように周辺の井戸
枯渇や地盤沈下といった弊害を引き起こすこともない、
という効果を奏する。[Effects of the Invention] As described in detail above, the present invention provides a water blocking wall that reaches the water impermeable layer from the ground surface around a structure provided on the ground, and an impermeable layer inside the water blocking wall. Since the groundwater in the upper aquifer is guided to the lower aquifer through the well, the groundwater level inside the water stop wall can be lowered without pumping the groundwater, As a result, liquefaction of the ground inside the water stop wall can be effectively prevented, and there is no adverse effect such as depletion of surrounding wells and land subsidence as in the past,
This has the effect.
第１図は本発明の一実施例を示す立断面図、第２図はそ
の平面図である。第３図は井戸の構成例を示す立断面図
である。第４図は本発明の他の実施例を示す立断面図、
第５図はその平面図である。 １……地盤、２……建築物、３……不透水層、４……上
部帯水層、５……下部帯水層、７……止水壁、８……井
戸、９……上部ストレーナ、10……下部ストレーナ、11
……ポンプ、20……地中構造物、 WL1……上部帯水層の地下水位、 WL2……下部帯水層の地下水位。FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view thereof. FIG. 3 is an elevational sectional view showing a configuration example of a well. FIG. 4 is an elevational sectional view showing another embodiment of the present invention,
FIG. 5 is a plan view thereof. 1 ... ground, 2 ... buildings, 3 ... impervious layer, 4 ... upper aquifer, 5 ... lower aquifer, 7 ... water barrier, 8 ... well, 9 ... upper Strainer, 10 ... Lower strainer, 11
… Pump, 20… Underground structure, WL 1 … Groundwater level of upper aquifer, WL 2 … Groundwater level of lower aquifer.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 ▲吉▼見 ▲吉▼昭 東京都中央区京橋２丁目16番１号 清水 建設株式会社内 (58)調査した分野(Int.Cl.6，ＤＢ名) E02D 27/34 E02D 3/10──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor ▲ Yoshi ▼ View ▲ Yoshi ▼ Akira Shimizu Construction Co., Ltd. 2-6-1 Kyobashi, Chuo-ku, Tokyo (58) Field surveyed (Int.Cl. 6 , DB (Name) E02D 27/34 E02D 3/10
Claims (1)
とが存する地盤の液状化を防止するための方法であっ
て、前記地盤に設ける構造物の周囲に地表から前記不透
水層に達する止水壁を設けるとともに、その止水壁の内
側に前記不透水層を貫通する井戸を設けて上部帯水層中
の地下水をその井戸を通して下部帯水層に導くことによ
り、前記止水壁の内側における上部帯水層中の地下水位
を低下せしめることを特徴とする地盤の液状化防止方
法。1. A method for preventing liquefaction of the ground in which an upper aquifer and a lower aquifer exist above and below an impermeable layer, the method comprising: By providing a water blocking wall reaching the water permeable layer, providing a well penetrating the impermeable layer inside the water blocking wall, and guiding groundwater in the upper aquifer to the lower aquifer through the well, A method for preventing liquefaction of ground, comprising lowering a groundwater level in an upper aquifer inside a water stop wall.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25288990A JP2777626B2 (en) | 1990-09-21 | 1990-09-21 | Ground liquefaction prevention method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25288990A JP2777626B2 (en) | 1990-09-21 | 1990-09-21 | Ground liquefaction prevention method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04131427A JPH04131427A (en) | 1992-05-06 |
| JP2777626B2 true JP2777626B2 (en) | 1998-07-23 |
Family
ID=17243576
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25288990A Expired - Fee Related JP2777626B2 (en) | 1990-09-21 | 1990-09-21 | Ground liquefaction prevention method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2777626B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3467266B1 (en) | 2002-09-17 | 2003-11-17 | 俊多 白石 | Prevention of ground liquefaction due to earthquake and facilities used for this method |
| JP2016205004A (en) * | 2015-04-23 | 2016-12-08 | 公益財団法人鉄道総合技術研究所 | Ground improvement method, ground improvement structure and improved ground |
-
1990
- 1990-09-21 JP JP25288990A patent/JP2777626B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04131427A (en) | 1992-05-06 |
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