JPH01271515A - Aseismic reinforcing construction for structure - Google Patents

Aseismic reinforcing construction for structure

Info

Publication number
JPH01271515A
JPH01271515A JP10156688A JP10156688A JPH01271515A JP H01271515 A JPH01271515 A JP H01271515A JP 10156688 A JP10156688 A JP 10156688A JP 10156688 A JP10156688 A JP 10156688A JP H01271515 A JPH01271515 A JP H01271515A
Authority
JP
Japan
Prior art keywords
perforated
caisson
mound
pile
seismic reinforcement
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.)
Pending
Application number
JP10156688A
Other languages
Japanese (ja)
Inventor
Yukio Saimura
幸生 才村
Osamu Iimura
飯村 修
Takeshi Iida
毅 飯田
Hiroshi Kida
浩 喜田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Priority to JP10156688A priority Critical patent/JPH01271515A/en
Publication of JPH01271515A publication Critical patent/JPH01271515A/en
Pending legal-status Critical Current

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  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
  • Revetment (AREA)

Abstract

PURPOSE:To facilitate execution of works and enhance the water exhausting characteristic by holding the top of a bored pile in a caisson mound, absorbing excessive gap water pressure from a hole in the liquefied layer position, and exhausting water from a hole in the mound position. CONSTITUTION:Below a caisson 1, a bored pile 4 provided with a number of small holes 5 for water communication is placed in such a way that at least the bored part is located in a liquefied layer 6 below a mound 7. As long as the bored part of the pile 4 lies within the liquefied layer 6 and the mound 7, the top of the pile 4 may be positioned at any level in the mound 7. Placing of the pile 4 is conducted by the use of a casing pipe.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 この発明は液状化の可能性のある砂地盤(以下、液状化
層という)上に設置されたケーソン式構造物の耐震補強
構造に関するものである。
[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an earthquake-resistant reinforcement structure for a caisson-type structure installed on sandy ground that is likely to liquefy (hereinafter referred to as a liquefaction layer). be.

〔従来の技術および解決しようとする課題〕ケーン2式
岸壁、護岸、防波堤などのケーソン式構造物の耐震補強
方法としては、従来、ケーソン11;1面または背面の
液状化層を振動棒やサンドコンパクションパイルなどに
より締固める工法があるが、ケーソン直下の液状化層を
締固め改良するには、ケーソンのリプレースが必要とな
り、工費面などから事実上不可能である。
[Prior art and problems to be solved] Conventionally, as a seismic reinforcement method for caisson-type structures such as cane type 2 quays, sea walls, and breakwaters, caisson 11; There are construction methods such as compaction piles, but to compact and improve the liquefaction layer directly beneath the caisson, the caisson must be replaced, which is virtually impossible due to construction costs.

5 そこで、第7図に示すようにケーソン底版2を貫通
して、孔あき抗4゛をケーソン1直下の液状化層6また
は液状化しない良好な地層17まで建込む工法が発明さ
れている。同工法では孔あき抗4゜がケーソン1内を貫
通し、ケーソン1上の地上部まで延び、液状化層6に発
生する過剰間隙水が孔あき抗4′の内部を通って、地上
部に排出される構造となっている。
5. Therefore, as shown in FIG. 7, a construction method has been devised in which a perforated shaft 4'' is built through the caisson bottom plate 2 to the liquefaction layer 6 directly below the caisson 1 or to the good stratum 17 that does not liquefy. In this construction method, a perforated shaft 4° penetrates through the inside of the caisson 1 and extends to the above-ground part of the caisson 1, and excess pore water generated in the liquefaction layer 6 passes through the perforated shaft 4' and reaches the above-ground part. It has a structure that allows it to be discharged.

このため、地上部に集水設備が必要となり、耐震補強杭
としての孔あき抗4°も長尺のものが必要とされる。ま
た、孔あき抗4”がケーソン1内を貫通するため、ケー
ソン中詰材3の流出防止のためのケーソン底版2の補修
が困難となるという問題があった。
For this reason, water collection equipment is required above ground, and seismic reinforcement piles with perforations as long as 4° are required. Further, since the perforated shaft 4'' penetrates the inside of the caisson 1, there is a problem in that it becomes difficult to repair the caisson bottom plate 2 to prevent the caisson filling material 3 from flowing out.

この発明は上述のような問題点の解決を図ったものであ
る。
This invention aims to solve the above-mentioned problems.

〔課題を解決するための手段〕[Means to solve the problem]

以下、この発明の概要を実施例に対応する図面の符号を
用いて説明する。
Hereinafter, an overview of the present invention will be explained using reference numerals in the drawings corresponding to the embodiments.

この発明が適用されるケーソン式構造物は液状化層6上
に形成されたマウンド7上にケーソン1を設置し、内部
に中詰材3を充填したもので、ケーソン式構造物の下方
に、多数の通水用の小孔5を設けた孔あき部を有する孔
あき抗4を、少なくとも前記孔あき部がマウンド7下方
の液状化層6内に位置するよう建込み、液状化層6内に
発生する過剰間隙水圧を孔あき抗4内に逸散させるよう
構成したものである。
The caisson type structure to which this invention is applied is one in which a caisson 1 is installed on a mound 7 formed on a liquefaction layer 6, and the inside is filled with a filling material 3, and below the caisson type structure, A perforated shaft 4 having a perforated part with a large number of small holes 5 for water passage is built so that at least the perforated part is located in the liquefaction layer 6 below the mound 7, and The structure is such that excess pore water pressure generated in the perforated shaft 4 is dissipated into the perforated shaft 4.

前述のように、このような耐震補強用の孔あき抗4をケ
ーソン式構造物の直下に設置する場合、従来は孔あき抗
4がケーソン1内を貫通し、ケーソン1上まで延び、液
状化層6に発生する過剰間隙水が孔あき杭4の内部を通
って、地上部に排出される構造となっていたのに対し、
この発明では孔あき杭4の上端をマウンド7内にとどめ
、従来より短くするとともに、孔あき杭4の孔あき部が
液状化層6およびマウンド7内に位置するよう建込んで
いる。孔あき抗4はマウンド7の上端まで延びる必要は
なく、孔あき杭4の上端がマウンド7内の任意の高さに
位置していてもよい。
As mentioned above, when installing such a perforated resistor 4 for seismic reinforcement directly under a caisson-type structure, conventionally the perforated resistor 4 penetrates inside the caisson 1 and extends above the caisson 1, preventing liquefaction. In contrast to the structure in which excess pore water generated in the layer 6 passes through the inside of the perforated pile 4 and is discharged to the above ground,
In this invention, the upper end of the perforated pile 4 is kept within the mound 7 and is made shorter than before, and the perforated pile 4 is built so that the perforated portion thereof is located within the liquefaction layer 6 and the mound 7. The perforated stake 4 does not need to extend to the upper end of the mound 7, and the upper end of the perforated pile 4 may be located at any height within the mound 7.

、 なお、この発明に使用する孔あき杭4としては、側
面に特開昭61−146910号公報あるいは特開昭6
2−211416号公報にみられるような多数の通水用
の小孔5を形成した鋼管杭を使用することができる。
In addition, the perforated pile 4 used in this invention has the side surface of JP-A-61-146910 or JP-A-6
A steel pipe pile having a large number of small holes 5 for water passage as seen in Japanese Patent No. 2-211416 can be used.

また、小孔5から土砂が孔あき杭4内部に流入しないに
ように、孔あき杭4の外側または内側の少なくとも片側
に、ポリエチレンなどの合成樹脂または金網などからな
るフィルターを取り付けるとよい。その他、孔あき抗4
としては孔あき部を設けた合成樹脂製パイプ(FRPパ
イプも含む)や孔あき部を有するコンクリートパイプの
他、例えば鋼と合成樹脂(ポリエチレン、ポリウレタン
、ポリスチレンなどを含む)、鋼とコンクリート、コン
クリートと合成樹脂、鋼とステンレス、綱とアルミなど
を組合わせた複合材料からなるパイプを使用することも
可能である。
Further, in order to prevent earth and sand from flowing into the perforated pile 4 through the small holes 5, it is preferable to attach a filter made of a synthetic resin such as polyethylene or a wire mesh to at least one side of the outside or inside of the perforated pile 4. Others, perforated resistance 4
In addition to synthetic resin pipes with perforated parts (including FRP pipes) and concrete pipes with perforated parts, examples include steel and synthetic resins (including polyethylene, polyurethane, polystyrene, etc.), steel and concrete, and concrete. It is also possible to use pipes made of composite materials such as combinations of steel and synthetic resin, steel and stainless steel, and steel and aluminum.

孔あき杭4の内部は液状化時の排水効果の点から、液状
化層6の最下端のレベル付近以上が中空であればよく、
良好な地層17に位置する部分については孔あき杭4の
内部が土砂などで密実であってもよい。さらに、孔あき
抗4の中空部は内部にフィルター材を取り付けあるいは
充填することもあるので、完全に中空でな(でもよく、
必要な排水機能を確保できるものであれば十分である。
In view of the drainage effect during liquefaction, the inside of the perforated pile 4 should be hollow above the level of the lowest end of the liquefaction layer 6.
For a portion located in a good geological stratum 17, the inside of the perforated pile 4 may be dense with earth and sand. Furthermore, since the hollow part of the perforated shaft 4 may be fitted with or filled with a filter material, it may not be completely hollow (although it may be
It is sufficient as long as it can secure the necessary drainage function.

〔作 用〕[For production]

上述のように構成することにより、液状化層6に発生す
る過剰間隙水を孔あき抗4の内部を通じて、マウンド7
内の孔あき部より排出することができる。
By configuring as described above, excess pore water generated in the liquefaction layer 6 is transferred to the mound 7 through the inside of the perforated shaft 4.
It can be discharged from the perforated part inside.

第5図はその作用を図示したもので、孔あき抗4にマウ
ンド7内への間隙水排出用の孔5を設けたことにより、
間隙水流入部から排出部までの距離も短くなり、排水性
能が高く、液状化層6の液状化防止効果も大きい。
FIG. 5 illustrates the effect. By providing holes 5 in the perforated shaft 4 for discharging pore water into the mound 7,
The distance from the interstitial water inflow part to the discharge part is also shortened, the drainage performance is high, and the liquefaction prevention effect of the liquefaction layer 6 is also large.

〔実施例〕〔Example〕

次に、実施例について説明する。 Next, examples will be described.

この発明では概略が第1図に示されるような孔あき抗4
を準備する。孔あき抗4は鋼管、ポリエチレンなどの合
成樹脂製の管などからなり、その上部に多数の小孔5が
設けられている。小孔5の形状は任意のものでよいが、
特に液状化層6内に位置する小孔5は、加工難易などの
観点から円形のものが好ましい。
In this invention, a perforated shaft 4 as shown schematically in FIG.
Prepare. The perforated shaft 4 is made of a steel pipe, a pipe made of synthetic resin such as polyethylene, etc., and has a large number of small holes 5 provided in its upper part. The small hole 5 may have any shape, but
In particular, the small holes 5 located in the liquefied layer 6 are preferably circular from the viewpoint of ease of processing.

ついで、第1図に示すようにケーソン式構造物を貫通さ
せて、液状化層6の下方地盤17まで孔あき杭4を建込
む。
Next, as shown in FIG. 1, perforated piles 4 are erected to penetrate the caisson-type structure and reach the ground 17 below the liquefaction layer 6.

孔あき抗4の本数、建込み箇所などはケーソン式岸壁、
護岸などの構造、地盤条件、孔あき杭4の直径、強度、
想定する地震の強度などによって決定する。
The number of perforated shafts 4, the construction location, etc. are based on the caisson type quay,
Structures such as bank protection, ground conditions, diameter and strength of perforated piles 4,
Determined based on the expected earthquake intensity, etc.

施工手順としては第7図に示す従来例と同様に、まず孔
あき抗4を建込む。すなわち、ケーソン中詰材3内にケ
ーシングパイプ(図示せず)をケーソン底版2に密着す
るまで押し込む。ケーシングパイプは内径が孔あき杭4
の外径より大きいものを用いる。ケーシングパイプ内の
中詰材はケーシングパイプ外に排除する。この後、ケー
ソン底版2をくり抜き、マウンド7内の捨石を液状化層
6上端まで掘削する。その後、孔あき抗4をケーシング
パイプ内を通じて建込み、液状化層6を貫通させ、支持
地盤まで根入れし、孔あき杭4の上端がケーソン1の上
面よりも所定高さ突き出た状態で停止する。液状化層6
内の孔あき抗4の内部の土砂は慣用のオーガー、グラブ
ハンマーなどにより孔あき杭4外に排出する。
The construction procedure is as in the conventional example shown in FIG. 7, in which the perforated shaft 4 is first erected. That is, a casing pipe (not shown) is pushed into the caisson filling material 3 until it comes into close contact with the caisson bottom plate 2. The casing pipe has a perforated pile with an inner diameter of 4
Use one that is larger than the outer diameter of. The filling material inside the casing pipe is removed to the outside of the casing pipe. Thereafter, the caisson bottom slab 2 is hollowed out, and the rubble in the mound 7 is excavated to the upper end of the liquefaction layer 6. After that, the perforated pile 4 is built through the casing pipe, penetrates the liquefaction layer 6, and is embedded in the supporting ground, and stops when the upper end of the perforated pile 4 protrudes from the upper surface of the caisson 1 by a predetermined height. do. Liquefaction layer 6
The earth and sand inside the inner perforated pile 4 is discharged to the outside of the perforated pile 4 using a conventional auger, grab hammer, etc.

次いで、ケーソン底版2下方のレベルで上記孔あき杭4
を水中切断する。水中切断の方法としてはディスクカッ
ター、アブレーシブウォータージエソト、砥石などによ
る方法を用いることができる。水中切断された孔あき抗
4は前記ケーシングパイプ内を通じてケーソン1上に出
せばよい。
Next, the perforated pile 4 is installed at a level below the caisson bottom slab 2.
Cut underwater. As a method for underwater cutting, a method using a disc cutter, an abrasive water die, a grindstone, etc. can be used. The perforated shaft 4 cut underwater may be brought out onto the caisson 1 through the casing pipe.

ケーソン底版2は穿孔された状態になっており、ケーソ
ン中詰材3の流出防止のため、補修する必要がある。
The caisson bottom plate 2 is perforated and needs to be repaired to prevent the caisson filling material 3 from flowing out.

この方法としては、例えば第2図(al〜(C)に示す
ように、底板11とフランジ12を有し、鋼材、ゴム系
材料、ポリエチレン等の高分子材料等からなる円筒体1
0を、前記ケーシングパイプ内から落とし込み、ケーソ
ン底版2の孔2aに嵌め込む。
In this method, for example, as shown in FIGS. 2A to 2C, a cylindrical body 1 having a bottom plate 11 and a flange 12 and made of steel, rubber material, polymeric material such as polyethylene, etc.
0 from inside the casing pipe and fit into the hole 2a of the caisson bottom plate 2.

フランジ12はケーソン底版2にボルト13などにより
、樹脂アンカーして強固に接着することもできる。円筒
体10の嵌設後、第2図(b)に示すように、円筒体I
O上部にモルタル14を打設する。
The flange 12 can also be firmly bonded to the caisson bottom plate 2 by resin anchoring with bolts 13 or the like. After fitting the cylindrical body 10, as shown in FIG. 2(b), the cylindrical body I
Place mortar 14 on top of O.

モルタル部の補強のため、あらかじめ鉄筋を円筒体IO
に溶着しておいてもよい。また、モルタル14と前記円
筒体10の一体化を増すために、第3図(a)〜(C)
に示すように、円筒体10のフランジ12にスタッドボ
ルト15を溶着しておいてもよい。さらに、第4図に示
すように円筒体10のケーソン底版2との接触部分に弾
性体16を装着し、円筒体10とケーソン底版2間に隙
間ができるのを防止することもできる。この弾性体16
としては、ゴム系材料、特殊ウレタンを主成分とする膨
潤製材料などを用いることができる。
To reinforce the mortar part, reinforcing bars were installed in advance into a cylindrical IO.
It may be welded to. Furthermore, in order to increase the integration of the mortar 14 and the cylindrical body 10, as shown in FIGS.
As shown in the figure, a stud bolt 15 may be welded to the flange 12 of the cylindrical body 10. Furthermore, as shown in FIG. 4, an elastic body 16 may be attached to the contact portion of the cylindrical body 10 with the caisson bottom plate 2 to prevent a gap from forming between the cylindrical body 10 and the caisson bottom plate 2. This elastic body 16
As the material, a rubber material, a swelling material containing special urethane as a main component, etc. can be used.

ケーシングパイプを引き抜き、ケーソン中詰材3の不足
分を補充して、ケーソン1の上蓋をコンクリートなどで
補修すれば、耐震補強が完了することとなる。
The seismic reinforcement is completed by pulling out the casing pipe, replenishing the missing caisson filling material 3, and repairing the top cover of the caisson 1 with concrete or the like.

第1図の実施例ではケーソン底版2の下方に孔あき抗4
を2列に配置したが、設計条件によっては1列配置とし
てもよい。また、第6図に示すように、ケーソンl前面
の地盤にも孔あき抗4を配置することができる。さらに
、第8図に示すように孔あき抗4は1列配置とし、ケー
ソン前面の地盤のみに建込むこともできる。これらの場
合、間隙水の排出は前面の孔あき抗4については、孔あ
き抗4の上端部から排水する機構としてもよいし、ケー
ソン底版2を貫通して配設した孔あき抗4のようにケー
ソンマウンド7内に排水する機構としてもよい。また、
孔あき抗4の上端部から排水するとともにケーソンマウ
ンド7内にも排水する機構としてもよい。
In the embodiment shown in FIG.
Although they are arranged in two rows, they may be arranged in one row depending on the design conditions. Further, as shown in FIG. 6, a perforated shaft 4 can also be placed in the ground in front of the caisson l. Furthermore, as shown in FIG. 8, the perforated shafts 4 can be arranged in one row and built only on the ground in front of the caisson. In these cases, the interstitial water can be drained from the upper end of the perforated shaft 4 on the front side, or by a mechanism such as a perforated shaft 4 installed through the caisson bottom plate 2. It may also be a mechanism for draining water into the caisson mound 7. Also,
A mechanism may be used in which water is drained from the upper end of the perforated pipe 4 and also into the caisson mound 7.

他の実施例を第9図〜第18図に示す。Other embodiments are shown in FIGS. 9 to 18.

第9図および第10図は孔あき抗4をそれぞれ3列、4
列配置とし、ケーソン底版2の直下のみならず、ケーソ
ン前面の地盤やケーソン背面の地盤にも建込み、耐震補
強性能を高めた例である。
Figures 9 and 10 show three and four rows of perforated resistors 4, respectively.
This is an example of an example in which the caisson is arranged in rows and built not only directly under the caisson bottom plate 2, but also on the ground in front of the caisson and the ground behind the caisson, improving seismic reinforcement performance.

第11図に示した構造では孔あき抗4をケーソン前面お
よび背面の地盤にのみ建込み、ケーソン底版2を貫通さ
せないため、ケーソン底版2の補修が不要であり、施工
が容易となる。
In the structure shown in FIG. 11, the perforated shafts 4 are built only in the ground on the front and back sides of the caisson and do not penetrate the caisson bottom plate 2, so there is no need to repair the caisson bottom plate 2, and construction is easy.

第12図の実施例では第11図の構造例に対し、マウン
ド7位置のみならず、マウンド7の前面の法尻にも孔あ
き抗4を設置したものである。この場合、前面法尻の孔
あき杭4については、液状化層6内の過剰間隙水圧を上
端から直接水中へ逸敗させるようになっている。
The embodiment shown in FIG. 12 differs from the structural example shown in FIG. 11 in that a perforated resistor 4 is installed not only at the position of the mound 7 but also at the foot of the slope in front of the mound 7. In this case, the perforated pile 4 at the foot of the front slope is designed to allow excess pore water pressure in the liquefaction layer 6 to escape directly into the water from the upper end.

第13図はケーソン1の底版2下方の液状化地盤を補強
するため、孔あき杭4を一部斜杭とした構造例を示した
ものである。斜杭と直抗は杭の耐荷力を増すため、同じ
場所で建込み、それらの上端を結んで組杭としてもよい
し、直杭と斜杭の建込み場所を法線方向で異なった位置
としてもよい。
FIG. 13 shows an example of a structure in which some of the perforated piles 4 are diagonal piles in order to reinforce the liquefied ground below the bottom slab 2 of the caisson 1. In order to increase the load-bearing capacity of the pile, diagonal piles and straight piles can be built in the same place and their upper ends tied together to form a set of piles, or straight piles and diagonal piles can be built in different positions in the normal direction. You can also use it as

第14図は第13図に示した構造例の机配置において、
捨石マウンド7前面の法尻に孔あき抗4を配置した例で
ある。
Figure 14 shows the desk arrangement of the structural example shown in Figure 13.
This is an example in which a perforated shaft 4 is arranged at the foot of a slope in front of a rubble mound 7.

捨石マウンド7前面の法尻から前方の液状化層6をサン
ドコンパクションパイル、振動棒などで締固めるか(第
15図参照)、合成樹脂、鋼などからなる中空孔あき管
21を該液状化層6に設置して(第16図参照)液状化
抵抗のある地盤18を造り、この地盤18と孔あき杭4
を組合せ配置した構造とすることもできる。もちろん、
液状化抵抗のある地盤18と孔あき抗4を組合せる場合
の孔あき抗4の配置はこの発明に述べる実施例のいずれ
の配置でもよい。孔あき管21は孔あき杭4のように側
方流動などに対する抵杭を期待しない場合には、必ずし
も良好な地層17に十分組入れする必要はなく、孔あき
抗4に比べて曲げ強度を減じてよい。
Either compact the liquefied layer 6 from the foot of the slope in front of the rubble mound 7 with a sand compaction pile, vibrating rod, etc. (see Fig. 15), or use a hollow perforated pipe 21 made of synthetic resin, steel, etc. to compress the liquefied layer. 6 (see Figure 16) to create a liquefaction-resistant ground 18, and connect this ground 18 with the perforated pile 4.
It is also possible to have a structure in which these are arranged in combination. of course,
When the liquefaction-resistant ground 18 and the perforated shaft 4 are combined, the perforated shaft 4 may be arranged in any of the embodiments described in this invention. If the perforated pipe 21 is not expected to provide resistance to lateral flow, etc., like the perforated pile 4, it is not necessarily necessary to fully incorporate it into the good stratum 17, and the bending strength will be reduced compared to the perforated pile 4. It's fine.

ケーソン式構造物の背面の裏埋土9については、従来、
振動棒やサンドコンパクションなどで締固めるか、砕石
ドレーンを設けるなどして液状化対策が採られていた。
Regarding the backfilling soil 9 at the back of a caisson-type structure, conventionally,
Countermeasures against liquefaction were taken, such as compacting with vibrating rods and sand compaction, or installing crushed stone drains.

これに対し、第17図に示すようにこの発明の孔あき抗
4を裏埋土9に建込み、液状化抑止対策とすることがで
きる。この場合、捨石マウンド7内を貫通する孔あき杭
4は第15図の場合のように、上端を捨石マウンド7内
に留めてもよいし、第17図に示すように良好な地層1
7から裏埋土19内にまで建込み、上端を裏埋土表面付
近に留めてもよい。また、裏埋土19内に建込む孔あき
抗4は、第17図に示す孔あき管21のように必ずしも
良好な地層17に十分組入れしない構造としてもよい。
On the other hand, as shown in FIG. 17, the perforated shaft 4 of the present invention can be built into the backfilling soil 9 as a measure to prevent liquefaction. In this case, the upper end of the perforated pile 4 penetrating through the rubble mound 7 may be kept within the rubble mound 7 as in the case of FIG.
7 to the inside of the backfill soil 19, and the upper end may be kept near the surface of the backfill soil. Further, the perforated shaft 4 built in the backfilling soil 19 may have a structure in which it is not necessarily incorporated sufficiently into the good stratum 17, like the perforated pipe 21 shown in FIG.

孔あき管21は液状化時の地盤拘束効果を期待せず、過
剰間隙水圧の逸散効果のみ期待する場合には、ケーソン
1の近くに建込む孔あき抗4に比べて曲げ強度を減じて
もよい。
If the perforated pipe 21 is not expected to have a ground restraint effect during liquefaction, but only to dissipate excess pore water pressure, the bending strength of the perforated pipe 21 should be reduced compared to the perforated pipe 4 built near the caisson 1. Good too.

第17図に示すように、ケーソン1の裏埋め側の液状化
対策としては、孔あき抗4あるいは孔あき管21または
両者を裏埋土9および液状化N6内に建込み、その後、
裏埋土9および液状化N6を振動棒などを用いる従来の
方法により締固め改良すれば、液状化抵抗の高い地盤、
すなわち裏埋土改良部19および液状化層改良部20を
効果的に造ることができる。地盤を振動棒などで締固め
ようとするとき地盤内の間隙水圧が高まるが、この間隙
水圧を締固め対象域外に逸敗しなければ、地盤を機械的
に振動させても地盤の締固めは困難である。この実施例
では、地盤の締固め前に孔あき抗4または孔あき管21
が地盤に設置されているので、締固め時の過剰間隙水圧
を孔あき杭4または孔あき管21を通じて容易に逸散で
き、地盤の深部まで極めて効果的に締固め改良すること
ができる。ケーソン式構造物以外に鋼矢板、鋼管矢板な
どから構成される直立壁構造の背後の裏埋土を改良する
場合においても、孔あき抗4または孔あき管21を用い
て、上記と同じ施工手順で地盤改良すれば、施工時、鋼
製構造物に発生する有害な海側へのはらみ出し変形、曲
げ応力を、孔あき抗4または孔あき管21を用いないで
地盤改良した場合に比べ、3〜5割程度以上減じること
が可能であり、極めて有効な液状化層位置を施すことが
できる。
As shown in FIG. 17, as a measure against liquefaction on the backfilling side of the caisson 1, a perforated shaft 4 or a perforated pipe 21, or both, are built in the backfilling soil 9 and the liquefaction N6, and then,
If the backfill soil 9 and liquefied N6 are compacted and improved by the conventional method using a vibrating rod, a ground with high liquefaction resistance can be created.
That is, the backfill soil improvement section 19 and the liquefaction layer improvement section 20 can be effectively created. When trying to compact the ground with a vibrating rod, the pore water pressure in the ground increases, but if this pore water pressure does not escape outside the area to be compacted, it will not be possible to compact the ground even if the ground is mechanically vibrated. Have difficulty. In this embodiment, the perforated shaft 4 or perforated pipe 21 is
Since it is installed in the ground, excess pore water pressure during compaction can be easily dissipated through the perforated piles 4 or perforated pipes 21, and compaction can be improved very effectively deep into the ground. In addition to caisson-type structures, when improving the backfill soil behind upright wall structures made of steel sheet piles, steel pipe sheet piles, etc., the same construction procedure as above can be applied using perforated shafts 4 or perforated pipes 21. If the ground is improved by using the perforated pipe 4 or the perforated pipe 21, the harmful seaward protrusion deformation and bending stress that occur in the steel structure during construction will be reduced compared to the case where the ground is improved without using the perforated resistor 4 or the perforated pipe 21. It is possible to reduce the amount by more than 30% to 50%, and it is possible to provide an extremely effective liquefaction layer position.

地震時には地盤の過剰間隙水圧を目詰まり防止フィルタ
ーを備えた孔あき杭または孔あき管の有孔部を通じて逸
散でき、従来の砕石ドレーンのように目詰まりして液状
化防止効果を失わせることもないので、施工効果の点、
地震時の液状化防止機能の点からこの発明の液状化対策
は極めて有効である。
During an earthquake, excess pore water pressure in the ground can be dissipated through the perforated section of a perforated pile or perforated pipe equipped with an anti-clogging filter, which prevents it from clogging and losing its liquefaction prevention effect like traditional crushed stone drains. Since there is no construction effect,
The liquefaction countermeasures of the present invention are extremely effective in terms of the liquefaction prevention function during earthquakes.

第18図は第17図に示した実施例の平面図に対応し、
孔あき杭4または孔あき管21の配置の一例を示したも
のである。
FIG. 18 corresponds to the plan view of the embodiment shown in FIG. 17,
An example of the arrangement of perforated piles 4 or perforated pipes 21 is shown.

第1図、第6図および第8図〜第18図に示した実施例
において、孔あき抗4の配置、径、肉厚、長さは液状化
地盤6の排水条件、ケーソン式構造物の耐震補強条件な
どの設計条件によって決定される。孔あき抗4を複数本
配置する場合も、孔あき抗4が必ずしもケーソン式構造
物の法線直角方向の同一断面に位置するとは限らず、千
鳥状にあるいはずらして配置される場合もある。また、
ケーソン底版2を貫通して建込む孔あき抗4の配置につ
いては、通常、ケーソン隔壁間に1本までとする。
In the embodiments shown in FIGS. 1, 6, and 8 to 18, the arrangement, diameter, wall thickness, and length of the perforated shaft 4 are determined based on the drainage conditions of the liquefied ground 6 and the caisson type structure. Determined by design conditions such as seismic reinforcement conditions. Even when a plurality of perforated resistors 4 are arranged, the perforated resistors 4 are not necessarily located in the same cross section in the direction perpendicular to the normal line of the caisson-type structure, but may be arranged in a staggered manner or in a staggered manner. Also,
As for the arrangement of perforated shafts 4 that penetrate through the caisson bottom plate 2, usually up to one perforated shaft 4 is installed between the caisson bulkheads.

〔発明の効果〕〔Effect of the invention〕

この発明では耐震補強杭としての孔あき杭の上端をケー
ソンマウンド内に保持し、地震時に砂質地盤である液状
化層に生じた過剰間隙水圧を液状化層位置の小孔より吸
収し、上部の小孔からマウンド内へ排水する構造とした
ため、間隙水流入部から排出部までの距離が短く、排水
性能が高く、液状化層の液状化防止効果も大きい。
In this invention, the upper end of the perforated pile as an earthquake-reinforced pile is held within the caisson mound, and the excess pore water pressure generated in the liquefaction layer, which is sandy ground, during an earthquake is absorbed through the small holes at the liquefaction layer position. Since the structure is such that water is drained into the mound through small holes, the distance from the pore water inflow part to the discharge part is short, the drainage performance is high, and the liquefaction layer is highly effective in preventing liquefaction.

また、ケーソン内を貫通させて配置する場合に比べ、杭
材が節約でき、ケーソン上部に集水枡等の設備を設ける
必要もないため、工費も大幅に低減させることができる
In addition, compared to the case where the caisson is placed through the interior of the caisson, pile materials can be saved, and there is no need to provide equipment such as a water collection basin above the caisson, so construction costs can be significantly reduced.

さらに、ケーソン式構造物の背面の裏埋土内にあらかじ
め孔あき杭または孔あき管を設置し、振動棒などで裏埋
土を締固め改良することにより、締固め時に発生する過
剰間隙水圧を孔あき抗または孔あき管を通じて容易に逸
散させ、地盤の深部まで極めて効果的に締固め改良する
ことができる。
In addition, by installing perforated piles or perforated pipes in the backfill soil at the back of the caisson-type structure and improving the compaction of the backfill soil with vibrating rods, excessive pore water pressure generated during compaction can be reduced. It can be easily dissipated through perforated shafts or perforated pipes and can improve compaction very effectively deep into the ground.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図はこの発明の一実施例における全体構造を示す鉛
直断面図、第2図(a)〜(C)はそれぞれケーソン底
版補修用の円筒体の平面図、補修部の鉛直断面図および
円筒体の斜視図、第3図(al〜(C1はそれぞれケー
ソン底版補修用円筒体の変形例を示す平面図、その補修
部の鉛直断面図および円筒体の斜視図、第4図は弾性体
を装着した場合の補修部の鉛直断面図、第5図はこの発
明の耐震補強構造の作用を説明するための鉛直断面図、
第6図は他の実施例を示す鉛直断面図、第7図は従来例
の鉛直断面図、第8図〜第17図はこの発明の他の実施
例を示す鉛直断面図、第18図は第17図の平面図であ
る。 1・・・ケーソン、2・・・底版、2a・・・孔、3・
・・中詰材、4・・・孔あき杭、5・・・小孔、6・・
・液状化層、7・・・捨石マウンド、8・・・裏込材、
9・・・裏埋土、10・・・円筒体、11・・・底板、
12・・・フランジ、13・・・ボルト、14・・・モ
ルタル(または鉄筋コンクリートまたは無筋コンクリー
ト)、15・・・スタンドボルト、16・・・弾性体、
17・・・良好な地層、18・・・液状化抵抗のある地
盤、19・・・裏埋土改良部、。 20・・・液状化層改良部、21・・・孔あき杭(また
は孔あき管) 第8図 第9図 第10図 第11図 第14図 第12図 第13図 第15図 第16図 第17図 第18図
FIG. 1 is a vertical sectional view showing the overall structure of an embodiment of the present invention, and FIGS. 2(a) to 2(C) are a plan view of a cylindrical body for repairing a caisson bottom plate, a vertical sectional view of a repaired part, and a cylindrical body, respectively. Figure 3 is a perspective view of the body, Figure 3 (al~ (C1 is a plan view showing a modified example of the cylindrical body for repairing the caisson bottom plate, a vertical sectional view of the repaired part, and a perspective view of the cylindrical body, Figure 4 is a diagram showing the elastic body). FIG. 5 is a vertical sectional view of the repaired part when installed, and FIG. 5 is a vertical sectional view for explaining the action of the seismic reinforcement structure of the present invention.
6 is a vertical sectional view showing another embodiment, FIG. 7 is a vertical sectional view of the conventional example, FIGS. 8 to 17 are vertical sectional views showing other embodiments of the present invention, and FIG. 18 is a vertical sectional view showing another embodiment of the present invention. FIG. 17 is a plan view of FIG. 17; 1... Caisson, 2... Bottom plate, 2a... Hole, 3...
...filling material, 4...perforated pile, 5...small hole, 6...
・liquefaction layer, 7... rubble mound, 8... backfilling material,
9... Back filling soil, 10... Cylindrical body, 11... Bottom plate,
12... Flange, 13... Bolt, 14... Mortar (or reinforced concrete or unreinforced concrete), 15... Stand bolt, 16... Elastic body,
17... Good geological stratum, 18... Soil with liquefaction resistance, 19... Backfill soil improvement section. 20... Liquefaction layer improvement section, 21... Perforated pile (or perforated pipe) Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 14 Fig. 12 Fig. 13 Fig. 15 Fig. 16 Figure 17 Figure 18

Claims (7)

【特許請求の範囲】[Claims] (1)マウンド上にケーソンを設置し、内部に中詰材を
充填してなる構造物の下方に、多数の通水用の小孔を設
けた孔あき部を有する孔あき杭を、少なくとも前記孔あ
き部が前記マウンド下方の液状化層に位置するよう建込
み、前記液状化層内に発生する過剰間隙水圧を前記孔あ
き杭内に逸散させるよう構成したケーソン式構造物の耐
震補強構造において、前記孔あき杭をその上端が前記マ
ウンド内に留まり、前記孔あき部が前記液状化層および
前記マウンド内に位置するよう建込んであることを特徴
とする構造物の耐震補強構造。
(1) A perforated pile having a perforated portion with a large number of small holes for water passage is installed at the bottom of a structure in which a caisson is installed on a mound and the inside is filled with filling material. A seismic reinforcement structure for a caisson-type structure constructed so that the perforated part is located in the liquefaction layer below the mound, and configured to dissipate excess pore water pressure generated in the liquefaction layer into the perforated pile. An earthquake-resistant reinforcing structure for a structure, characterized in that the perforated pile is built so that its upper end remains within the mound, and the perforated portion is located within the liquefaction layer and the mound.
(2)孔あき杭はケーソン式構造物の底版直下のマウン
ド内およびその下方地盤に位置している請求項1記載の
構造物の耐震補強構造。
(2) The seismic reinforcement structure for a structure according to claim 1, wherein the perforated pile is located in the mound directly below the bottom slab of the caisson-type structure and in the ground below the mound.
(3)孔あき杭はケーソン式構造物の前面下方のマウン
ド内およびその下方地盤に位置している請求項1記載の
構造物の耐震補強構造。
(3) The seismic reinforcement structure for a structure according to claim 1, wherein the perforated pile is located in a mound below the front surface of the caisson-type structure and in the ground below the mound.
(4)ケーソン式構造物の背面にも孔あき杭を構造物下
方のマウンド内およびその下方地盤に位置するよう設置
してある請求項1、2または3記載の構造物の耐震補強
構造。
(4) The seismic reinforcement structure for a structure according to claim 1, 2 or 3, wherein perforated piles are also installed on the back of the caisson type structure so as to be located in the mound below the structure and in the ground below it.
(5)ケーソン式構造物の背面には上端がケーソン式構
造物背面の裏埋土表面付近に達する孔あき杭を設置して
ある請求項1、2または3記載の構造物の耐震補強構造
(5) The seismic reinforcement structure for a structure according to claim 1, 2 or 3, wherein a perforated pile is installed on the back surface of the caisson structure, the upper end of which reaches near the surface of the backfilling soil on the back surface of the caisson structure.
(6)ケーソン式構造物の捨石マウンド前面の法尻から
前方の液状化層には複数本の孔あき管を設置してある請
求項1、2または3記載の構造物の耐震補強構造。
(6) The seismic reinforcement structure for a structure according to claim 1, 2 or 3, wherein a plurality of perforated pipes are installed in the liquefaction layer in front of the slope end in front of the rubble mound of the caisson type structure.
(7)ケーソン式構造物の背面の裏埋土内には該裏埋土
締固め改良時および施工後の裏埋土および下方地盤に発
生する過剰間隙水圧を逸散させるための孔あき管が設置
されていることを特徴とする請求項1、2または3記載
の構造物の耐震補強構造。
(7) There is a perforated pipe in the backfilling soil at the back of the caisson type structure to dissipate excess pore water pressure that occurs in the backfilling soil and the underlying ground during the compaction improvement of the backfilling soil and after construction. The seismic reinforcement structure for a structure according to claim 1, 2 or 3, wherein the seismic reinforcement structure is installed.
JP10156688A 1988-04-25 1988-04-25 Aseismic reinforcing construction for structure Pending JPH01271515A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10156688A JPH01271515A (en) 1988-04-25 1988-04-25 Aseismic reinforcing construction for structure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10156688A JPH01271515A (en) 1988-04-25 1988-04-25 Aseismic reinforcing construction for structure

Publications (1)

Publication Number Publication Date
JPH01271515A true JPH01271515A (en) 1989-10-30

Family

ID=14303960

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10156688A Pending JPH01271515A (en) 1988-04-25 1988-04-25 Aseismic reinforcing construction for structure

Country Status (1)

Country Link
JP (1) JPH01271515A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000248527A (en) * 1999-02-25 2000-09-12 Kajima Corp Earthquake resistant reinforcing method for existing structure
JP2017071901A (en) * 2015-10-05 2017-04-13 中国電力株式会社 Underwater compaction method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000248527A (en) * 1999-02-25 2000-09-12 Kajima Corp Earthquake resistant reinforcing method for existing structure
JP2017071901A (en) * 2015-10-05 2017-04-13 中国電力株式会社 Underwater compaction method

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