JP2001317043A - Sheet-pile wall for separation against settlement - Google Patents
Sheet-pile wall for separation against settlementInfo
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- JP2001317043A JP2001317043A JP2000139147A JP2000139147A JP2001317043A JP 2001317043 A JP2001317043 A JP 2001317043A JP 2000139147 A JP2000139147 A JP 2000139147A JP 2000139147 A JP2000139147 A JP 2000139147A JP 2001317043 A JP2001317043 A JP 2001317043A
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- sheet pile
- steel sheet
- floating
- embankment
- submerged
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、支柱付き鋼矢板工
法による沈下防止用の縁切り矢板壁に関し、更に詳しく
述べると、地盤内の支持層まで達する着底支柱と、軟弱
層の途中まで挿入される複数のフローティング鋼矢板群
を交互に配置して壁面とし、それらを頭部で結合し一体
化した構造の沈下縁切り矢板壁に関するものである。こ
の技術は、軟弱地盤上の盛土施工に伴う周辺地盤への悪
影響を防ぐのに有用である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perforated sheet pile wall for preventing subsidence by a steel sheet pile method with columns, and more particularly, to a bottom support column reaching a support layer in the ground and a partly inserted soft layer. A plurality of floating steel sheet pile groups are alternately arranged to form a wall surface, and they are connected by a head to form a submerged edge sheet pile wall. This technique is useful for preventing adverse effects on the surrounding ground due to embankment construction on soft ground.
【０００２】[0002]
【従来の技術】河川下流部では厚い軟弱土が分布してい
ることが多く（例えば、熊本平野を流下する白川・緑川
の下流部では、厚さ４０ｍにも及ぶ軟弱土が分布してい
る）、このような軟弱地盤上に築堤盛土を行った場合に
は、長期間にわたって圧密沈下を生じるために、周辺家
屋に傾斜や変状・亀裂等を与える他、水田に対しても水
たまりを発生させるなどの様々な沈下障害を引き起こす
ことになる。2. Description of the Related Art Thick soft soil is often distributed in the lower part of rivers (for example, in the lower part of Shirakawa and Midorikawa flowing down the Kumamoto Plain, soft soil as thick as 40 m is distributed). However, when embankment is constructed on such soft ground, in order to cause consolidation settlement for a long period of time, slopes, deformation, cracks, etc. are given to surrounding houses, and puddles also occur in paddy fields And various subsidence disorders.
【０００３】そこで、従来、周辺地盤へ及ぼす地盤沈下
などの悪影響を防止するために、盛土のり尻に、多数枚
の長尺の鋼矢板を、軟弱層を貫通し支持層に達するまで
打設する工法（これを、「着底型の鋼矢板工法」と称す
る）が行われてきた。つまり従来の着底型の鋼矢板工法
は、ほぼ同じ長さの多数の鋼矢板を使用し、全ての鋼矢
板を軟弱層の下位の支持層まで一列に打設して壁面（矢
板壁）を構築する工法である。Conventionally, in order to prevent adverse effects such as land subsidence on the surrounding ground, a large number of long steel sheet piles are cast at the tail of the embankment until they penetrate the soft layer and reach the support layer. A construction method (referred to as a “bottomed steel sheet pile construction method”) has been performed. In other words, the conventional bottoming-type steel sheet pile construction method uses a number of steel sheet piles of almost the same length, and all steel sheet piles are cast in a line to the lower support layer of the soft layer to form the wall (sheet pile wall). This is a construction method.
【０００４】このような着底型の鋼矢板工法を施工した
後の沈下、変形などの動態測定結果によれば、沈下の縁
切りは顕著であり、対策の効果は明瞭であった。例え
ば、熊本平野での築堤施工後の層別沈下計の観測データ
によると、着底型の鋼矢板工法を施工した区間では、盛
土中央で約８年間に６９cmの沈下が生じているのに対し
て、堤内側地層の沈下量は１．６cmであった。[0004] According to the dynamic measurement results of settlement, deformation and the like after the construction of the bottomed steel sheet pile method, the margin of settlement is remarkable, and the effect of the countermeasure is clear. For example, according to the observation data of a stratified subsidence meter after embankment construction in the Kumamoto Plain, in the section where the bottomed steel sheet pile construction method was constructed, a settlement of 69 cm occurred at the center of the embankment for about 8 years. The subsidence amount of the embankment was 1.6 cm.
【０００５】[0005]
【発明が解決しようとする課題】このように着底型の鋼
矢板工法の有効性は立証されているが、反面、極めて不
経済であるという大きな欠点があった。例えば、上記の
熊本平野の海岸近くでは４０ｍ以上の打設長が必要であ
った。我が国においては、関東平野をはじめとして各地
の平野でも、このように４０ｍ程度もしくはそれ以上の
軟弱層が存在する地域は多く見られる。このような長尺
の鋼矢板を打設するには、鋼矢板の運搬や打設等の観点
から、最大でも２０〜３０ｍ程度の長さの鋼矢板を用
い、その鋼矢板を打設し、現場で溶接して継ぎ足し、更
に打設するという作業が必要となる。このような作業を
全ての鋼矢板について行わねばならない。従って、１枚
の長尺鋼矢板の打設に煩瑣な作業が要求される。途中で
溶接継ぎ足し作業のために一旦打設作業を中断すること
から、その後の打設が困難となる場合も生じ、作業時間
が長くかかる。そのため、矢板壁の構築に膨大な工事費
用を必要とし、工期も長くかかる。Although the effectiveness of the bottomed steel sheet pile method has been proved as described above, it has a serious disadvantage that it is extremely uneconomical. For example, near the coast of the Kumamoto Plain, a casting length of 40 m or more was required. In Japan, the Kanto Plain and other plains often have such a soft layer of about 40 m or more. In order to drive such a long steel sheet pile, from the viewpoint of transporting and driving the steel sheet pile, a steel sheet pile having a length of at most about 20 to 30 m is used, and the steel sheet pile is driven. It is necessary to perform work of welding, adding, and further placing on site. Such work must be performed on all sheet piles. Therefore, complicated work is required for driving one long sheet pile. Since the casting operation is temporarily interrupted in the middle for the welding addition operation, the subsequent casting may become difficult, and the working time is long. Therefore, huge construction cost is required to construct the sheet pile wall, and the construction period is long.
【０００６】ところで、このような着底型の鋼矢板工法
とその後の観測によって、築堤盛土により沈下が生じる
のは、軟弱層約４０ｍの約半分の２０ｍより浅い地層に
限られるという重要な知見が得られた。そこで、軟弱層
の中途まで鋼矢板を打設する工法（これを、「フローテ
ィング鋼矢板工法」と称する）が提案され、その実験が
試みられた。しかし、このようなフローティング鋼矢板
工法は、工事期間の短縮、工事費用の削減には有効であ
るが、着底型の鋼矢板工法と比べて沈下低減効果は小さ
く、また鋼矢板長が短いほど、沈下の縁切り効果は小さ
かった。築堤盛土により沈下が生じるのは、軟弱粘土層
約４０ｍの約半分の２０ｍより浅い地層に限られるとい
う点では、着底型の鋼矢板工法同様であったが、当初の
予想に反して、単に鋼矢板を短くするだけでは、沈下の
縁切り効果が十分ではないことが判明した。[0006] By the way, the bottoming-type steel sheet pile method and subsequent observations have shown that it is important to note that subsidence caused by embankment is limited to a layer less than 20 m, which is about half of the soft layer of about 40 m. Obtained. Therefore, a method of driving a steel sheet pile into the middle of the soft layer (this method is referred to as a “floating steel sheet pile method”) has been proposed, and an experiment thereof has been attempted. However, such a floating steel sheet pile method is effective in shortening the construction period and reducing the construction cost, but the settlement reduction effect is small compared to the bottom type steel sheet pile method, and the shorter the steel sheet pile length is, The marginal effect of settlement was small. Subsidence caused by embankment embankment is similar to the bottomed steel sheet pile construction method in that the subsidence caused by embankment is limited to a layer that is shallower than 20 m, which is about half of the soft clay layer of about 40 m. It has been found that simply shortening the steel sheet pile is not sufficient for the marginal effect of settlement.
【０００７】本発明の目的は、十分な沈下の縁切り効果
が生じ、しかも施工が容易で、工期の短縮、工事費用の
大幅な削減が可能となるような沈下縁切り矢板壁を提供
することである。[0007] An object of the present invention is to provide a submerged edge-cut sheet pile wall which has a sufficient settlement effect of subsidence, is easy to construct, can shorten the construction period, and can greatly reduce the construction cost. .
【０００８】[0008]
【課題を解決するための手段】本発明は、地盤内に軟弱
層を貫通して支持層まで達する着底支柱が間隔をおいて
配設され、該着底支柱の間に軟弱層の途中まで挿入され
る単一もしくは複数のフローティング鋼矢板が設置され
ることで壁面が形成され、着底支柱とフローティング鋼
矢板とが、それらの頭部で結合一体化されている沈下縁
切り矢板壁である。フローティング鋼矢板は、通常、軟
弱層における沈下する地層以深まで挿入される。SUMMARY OF THE INVENTION According to the present invention, there is provided a bottom strut extending through a soft layer and reaching a support layer in the ground at an interval, and between the bottom struts and in the middle of the soft layer. A wall surface is formed by installing one or a plurality of floating steel sheet piles to be inserted, and the bottom strut and the floating steel sheet pile are a submerged edge-cut sheet pile wall integrally connected at their heads. Floating steel sheet piles are usually inserted deeper than the sinking formations in the soft formations.
【０００９】この沈下対策工法の基本的な考え方は、
（１）築堤盛土によって沈下が生じない深度までフロー
ティング鋼矢板を打設すること、（２）築堤による引き
込みが生じても、鋼矢板が沈下しないような構造にする
こと、の２条件を満足することである。そこで、上記
（１）の条件を満たすため、フローティング鋼矢板は、
軟弱層の途中、具体的には沈下する地層以深まで挿入す
る。また上記（２）の条件を満たすため、フローティン
グ鋼矢板の頭部を連結して一体構造とし、ある間隔毎に
沈下防止のための着底支柱を設け、その着底支柱もフロ
ーティング鋼矢板と一体構造にする。という解決手段を
採用している。[0009] The basic idea of this settlement method is:
(1) The floating steel sheet pile is driven to a depth at which settlement does not occur due to the embankment embankment, and (2) The structure is such that the steel sheet pile does not sink even if the embankment draws in. That is. Therefore, to satisfy the above condition (1), the floating steel sheet pile is
It is inserted in the middle of the soft layer, specifically, deeper than the subsidence. In order to satisfy the above condition (2), the heads of the floating steel sheet piles are connected to form an integral structure, and a bottom support column is provided at certain intervals to prevent settlement, and the bottom support column is also integrated with the floating steel sheet pile. Make structure. The solution is adopted.
【００１０】このように、異なる長さの着底支柱とフロ
ーティング鋼矢板とを組み合わせて壁体状にすること、
フローティング鋼矢板に作用する力を着底支柱に受け持
たせて支持すること、という点が、本発明の特徴であ
る。[0010] Thus, the bottom supports and floating steel sheet piles of different lengths are combined to form a wall.
The feature of the present invention is that the bottom strut is supported by supporting the force acting on the floating steel sheet pile.
【００１１】[0011]
【発明の実施の形態】地盤の性状、盛土の形、沈下層の
深さなどによっても異なるが、通常、着底支柱１本に対
してフローティング鋼矢板を３〜１０枚程度の割合で組
み合わせる。より好ましくは、着底支柱１本に対してフ
ローティング鋼矢板を５〜１０枚程度の割合で組み合わ
せる。フローティング鋼矢板の長さは、沈下が生じない
深度までの長さとする必要があり、好ましくは、軟弱層
の４０〜８０％程度であり、通常、軟弱層の４０〜６０
％程度でよい。BEST MODE FOR CARRYING OUT THE INVENTION Normally, about 3 to 10 floating steel sheet piles are combined with one bottom support, although it depends on the properties of the ground, the shape of the embankment, the depth of the subsidence layer, and the like. More preferably, about 5 to 10 floating steel sheet piles are combined with one landing support. The length of the floating steel sheet pile needs to be a length up to a depth at which settlement does not occur, and is preferably about 40 to 80% of the soft layer, and usually 40 to 60% of the soft layer.
%.
【００１２】着底支柱は、Ｈ型鋼、鋼管杭、組み合わせ
矢板など任意の構造の支柱でもよいが、施工する地盤の
支持層に達するまで打設することが可能であるならばフ
ローティング鋼矢板と同じ断面形状の長尺の着底鋼矢板
を用いるのが最適である。そのようにすれば、フローテ
ィング鋼矢板と同じ機械で着底鋼矢板を打ち込むことが
でき、作業能率が向上するからである。フローティング
鋼矢板は任意の断面形状のものが使用できるが、一般的
な断面Ｕ形のものでよい。各鋼矢板同士の両縁の継手部
分が組み合わされるように打設する。The bottom support may be a support of any structure, such as an H-section steel, a steel pipe pile, or a combination sheet pile, but is the same as a floating steel sheet pile if it can be driven until it reaches the support layer of the ground to be constructed. It is best to use a long bottomed steel sheet pile with a cross-sectional shape. By doing so, the bottomed steel sheet pile can be driven by the same machine as the floating steel sheet pile, and work efficiency is improved. The floating steel sheet pile can have any cross-sectional shape, but may have a general U-shaped cross section. The steel sheet piles are cast so that the joints at both edges are combined.
【００１３】着底鋼矢板とフローティング鋼矢板の頭部
の両側に、棒状の連結部材を当接し連結ボルトを用いて
締結すると共に、両側に位置する連結部材の間に結合部
材を間隔をおいて介在させて連結ボルトを用いて締結す
ることにより、壁面全体を結合一体化するのが好まし
い。連結部材は、棒状で剛性に優れたものがよく、例え
ばＵ型鋼、Ｈ型鋼、Ｌ型鋼などを用いる。結合部材は、
例えば四角筒型の鋼材、あるいはＨ型鋼などでよく、着
底鋼矢板の位置など適当な間隔をおいて介装すればよ
い。連結部材のみでは、鋼矢板は交互に片側の連結部材
に締結されただけの状態であり、それらは隣接する鋼矢
板同士の継手部分で連結しているだけの状態である。そ
こで、結合部材により両側の連結部材間を相互に結合す
ることで、全ての鋼矢板が強固に一体となった構造を実
現できる。[0013] A rod-shaped connecting member is brought into contact with both sides of the head of the bottomed steel sheet pile and the floating steel sheet pile and fastened using connecting bolts, and a connecting member is provided between the connecting members located on both sides with a space therebetween. It is preferable that the entire wall surface be joined and integrated by being fastened using a connecting bolt with the interposition therebetween. The connecting member is preferably a bar-shaped member having excellent rigidity. For example, a U-shaped steel, an H-shaped steel, an L-shaped steel, or the like is used. The coupling member is
For example, it may be a square tube-type steel material or an H-shaped steel, and may be interposed at appropriate intervals such as the position of a bottomed steel sheet pile. With only the connecting members, the steel sheet piles are alternately fastened to the connecting members on one side alternately, and they are merely connected at the joints between adjacent steel sheet piles. Therefore, a structure in which all the steel sheet piles are firmly integrated can be realized by mutually connecting the connecting members on both sides by the connecting members.
【００１４】なお本発明は、河川における築堤盛土の
他、軟弱地盤上に設ける道路や鉄道線路などの盛土、あ
るいは造成地の盛土などにも適用できる。築堤盛土の場
合には堤内側の盛土のり尻に施工すればよいが、その他
の場合には両側あるいは周囲の盛土のり尻に施工するこ
とになる。The present invention can be applied not only to embankment embankments in rivers, but also to embankments such as roads and railroad tracks provided on soft ground, or embankments in lands to be laid. In the case of embankment embankment, the embankment may be installed on the embankment inside the embankment, but in other cases, the embankment may be installed on both sides or the surrounding embankment.
【００１５】[0015]
【実施例】図１は本発明に係る沈下縁切り矢板壁の一実
施例を示す説明図であり、河川における築堤盛土に適用
した例である。軟弱地盤１０の上に堤防１２が構築され
ている。図面左手側を堤外側、右手側を堤内側とする。
堤内側の盛土のり尻に沈下縁切り矢板壁２０を施工す
る。この沈下縁切り矢板壁２０の詳細を図２に示す。図
２において、Ａは平面図を、Ｂは正面図を、Ｃはｘ−ｘ
断面を、Ｄはｙ−ｙ断面を、それぞれ表している。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing one embodiment of a submerged edge cut sheet pile wall according to the present invention, and is an example applied to embankment embankment in a river. A dike 12 is constructed on the soft ground 10. The left hand side of the drawing is the outside of the embankment, and the right hand side is the inside of the embankment.
At the bottom of the embankment inside the embankment, a subsidence edge-cut sheet pile wall 20 is constructed. FIG. 2 shows details of the squatting edge sheet pile wall 20. 2, A is a plan view, B is a front view, and C is xx.
D represents the yy section.
【００１６】地盤内の軟弱層１０を貫通し支持層１４ま
で達する着底鋼矢板２２を打設し、それに隣接して軟弱
層の途中までフローティング鋼矢板２４を挿入する。こ
こでは、着底鋼矢板２２及びフローティング鋼矢板２４
は、全て同一断面形状のＵ形鋼矢板を使用している。着
底鋼矢板２２は、若干支持層１４に貫入する状態まで打
ち込むのがよい。フローティング鋼矢板２４は複数枚
（図では７枚）向きを交互に変えて一列に並べ配置す
る。そして最終端の（７枚目の）フローティング鋼矢板
に隣接して次の着底鋼矢板を打設する。このような作業
を繰り返す。これによって、着底鋼矢板２２が間隔をお
いて配設され、該着底鋼矢板２２の間に複数枚のフロー
ティング鋼矢板２４が並設されることで、各鋼矢板の両
縁の継手部分が組み合わせられた壁面が構成される。そ
の後、全ての着底鋼矢板２２とフローティング鋼矢板２
４を、それらの頭部で結合一体化する。A bottomed steel sheet pile 22 that penetrates the soft layer 10 in the ground and reaches the support layer 14 is cast, and a floating steel sheet pile 24 is inserted adjacent to the middle of the soft layer. Here, the bottomed steel sheet pile 22 and the floating steel sheet pile 24
All use U-shaped steel sheet piles having the same cross-sectional shape. The bottomed steel sheet pile 22 is preferably driven into the support layer 14 until it slightly penetrates. The plurality of floating steel sheet piles 24 (seven in the drawing) are arranged alternately in a line. Then, the next bottomed steel sheet pile is driven next to the final (seventh) floating steel sheet pile. This operation is repeated. As a result, the bottomed steel sheet piles 22 are arranged at intervals, and a plurality of floating steel sheet piles 24 are juxtaposed between the bottomed steel sheet piles 22 so that joint portions at both edges of each steel sheet pile are provided. Are combined to form a wall surface. Then, all the bottomed steel sheet piles 22 and floating steel sheet piles 2
4 are joined together at their heads.
【００１７】この実施例では、上記のように着底支柱と
してフローティング鋼矢板と同じ断面形状の長尺の鋼矢
板を用いているため、全ての鋼矢板を同じ機械で打設す
ることができ、効率的に作業が行える。なお鋼矢板は、
運搬や打設などの観点から、通常、最大２０〜３０ｍ程
度の長さである。そこで、着底鋼矢板の必要長さがそれ
よりも長くなる場合には、１枚の鋼矢板を打設した後に
次の鋼矢板を溶接により継ぎ足し、再び打設する作業を
繰り返すことで、少なくとも支持層に達する所定の深さ
まで挿入する。なお、フローティング鋼矢板の長さは、
一般に軟弱層の深さの４０〜８０％程度とする。従っ
て、フローティング鋼矢板は殆ど当初から連続している
１枚の鋼矢板のみで打設できる。In this embodiment, since the long steel sheet pile having the same cross-sectional shape as the floating steel sheet pile is used as the bottom support as described above, all the steel sheet piles can be driven by the same machine. Work can be done efficiently. The steel sheet pile is
From the viewpoint of transportation and casting, the length is usually about 20 to 30 m at the maximum. Therefore, if the required length of the bottomed steel sheet pile is longer than that, at least by repeating the work of placing one steel sheet pile, adding the next steel sheet pile by welding, and placing again, Insert to a predetermined depth reaching the support layer. The length of the floating steel sheet pile is
Generally, it is set to about 40 to 80% of the depth of the soft layer. Therefore, the floating steel sheet pile can be driven by only one steel sheet pile which is almost continuous from the beginning.
【００１８】着底鋼矢板２２とフローティング鋼矢板２
４の頭部の横方向両側に、連結部材２６（図２では横向
きに設けたＵ型鋼）を当接して各鋼矢板２２，２４に連
結ボルト２８で締結する。しかしこれだけでは、隣接す
る鋼矢板同士がそれらの継手部分で単に組み合わさって
いるだけなので、更に両側の連結部材２６の間に（ここ
では着底鋼矢板２２の位置）に四角筒型鋼材からなる結
合部材３０を挿入し、それに両方の連結部材２６を連結
ボルト２８で締結する。これによって全ての鋼矢板が結
合一体化された沈下縁切り矢板壁２０となる。Bottom steel sheet pile 22 and floating steel sheet pile 2
A connecting member 26 (a U-shaped steel provided in a horizontal direction in FIG. 2) is brought into contact with both lateral sides of the head of No. 4 and fastened to the steel sheet piles 22 and 24 by connecting bolts 28. However, in this case alone, since the adjacent steel sheet piles are merely combined at their joint portions, the square sheet steel is further provided between the connecting members 26 on both sides (here, the position of the bottom steel sheet pile 22). The connecting member 30 is inserted, and both connecting members 26 are fastened to the connecting member 30 by connecting bolts 28. This results in a sunk edge sheet pile wall 20 in which all steel sheet piles are joined and integrated.
【００１９】各フローティング鋼矢板２４は、軟弱層１
０において沈下が生じない深さまで挿入することが基本
である。一般には、盛土荷重によって地中には増加応力
が発生する。この増加後の応力が地盤の圧密降伏応力を
上回った場合には沈下を生じることになる。Each floating steel sheet pile 24 has a soft layer 1
Basically, it is inserted to a depth at which no subsidence occurs at zero. Generally, an increased stress is generated in the ground by the embankment load. If the stress after this increase exceeds the consolidation yield stress of the ground, settlement will occur.
【００２０】ところで、着底鋼矢板の間隔や頭部連結工
の設計のためには、鋼矢板に作用する外力を求めておく
ことが必要である。図３に鋼矢板に作用する外力の模式
図を示す。図示のように鉛直方向については、堤体側の
鋼矢板の面には、押し込み力（下向きの摩擦力）Ｆａが
中立点まで作用し、それ以深は上向きの摩擦力Ｆｂが生
じる。堤内側の鋼矢板の面の中立点以深には上向きの摩
擦力ｆが生じる。ここで中立点とは、鋼矢板と地盤間の
相対沈下が０となる点である。更に、断面積が微小であ
り工学的には無視しうるかもしれないが、鋼矢板の下端
には先端支持力Ｒが作用するものと考えられる。次に水
平方向については、盛土荷重による側方流動圧Ｐが堤体
側の鋼矢板の面に作用するのに対して、その反対側の堤
内側の鋼矢板の面には、水平移動に対抗しようとする地
盤反力Ｐｒが作用する。なお、大きな側方流動が生じる
ような地盤では、鋼矢板の変形によって副次的な沈下が
生じ、鉛直方向の外力にも影響を及ぼすことがあるの
で、考慮に入れておく必要がある。By the way, in order to design the interval between the bottomed steel sheet piles and the design of the head connecting work, it is necessary to obtain the external force acting on the steel sheet piles. FIG. 3 shows a schematic diagram of the external force acting on the steel sheet pile. As shown in the figure, in the vertical direction, a pushing force (downward frictional force) Fa acts on the surface of the steel sheet pile on the bank body side up to the neutral point, and an upward frictional force Fb is generated at a depth lower than that. An upward frictional force f is generated below the neutral point of the steel sheet pile inside the embankment. Here, the neutral point is a point at which the relative settlement between the steel sheet pile and the ground becomes zero. Furthermore, although the cross-sectional area is very small and may be negligible from an engineering point of view, it is considered that the tip supporting force R acts on the lower end of the steel sheet pile. Next, in the horizontal direction, while the lateral flow pressure P due to the embankment load acts on the steel sheet pile surface on the embankment side, the opposite side of the steel sheet pile surface on the inside of the embankment will oppose horizontal movement. The ground reaction force Pr acts as follows. In the ground where large lateral flow occurs, it is necessary to take into account that deformation of the steel sheet pile causes subsidence, which may affect the external force in the vertical direction.
【００２１】上述した鉛直方向の外力のうち、地盤と鋼
矢板の間に作用する摩擦力の向きは微妙なバランスで変
化することが考えられる。即ち、鋼矢板の沈下に比べ地
盤の沈下が大きい場合は、下向きの摩擦力が作用し、そ
の反対に地盤の沈下量が小さい場合には、上向きの摩擦
力が作用することになる。このように、地盤の沈下量と
鋼矢板の沈下量を詳細に予測した上でないと厳密な意味
では矢板壁の設計を行うことが困難である。そこで、地
盤の状況を勘案し、以下の仮定のもとに簡便化を図るこ
ととした。 ・盛土下部地盤の表層に砂質土が厚く分布しているよう
な場合には、築堤に伴う側方流動は殆ど発生しない地盤
であるため、水平方向の外力や変形は考えないこととす
る。 ・熊本平野での築堤後の観測結果によると、中立点は堤
体側及び堤内側の双方で軟弱層厚の半分の深度に位置し
ていることが判明しているため、これより深部で上向き
の摩擦力が生じるものとする。 ・堤内地盤は、鋼矢板とほぼ同じ沈下量が生じるため、
堤内側の中立点以浅には下向きの摩擦力は生じないもの
とする。 以上の仮定をふまえて作成した外力の簡略化した模式図
を図４に示す。これらの外力のうち、押し込み力Ｆと摩
擦力ｆは室内土質試験結果から、ＲはＮ値やコーン貫入
試験結果等からの算出が可能である。It is conceivable that the direction of the frictional force acting between the ground and the steel sheet pile changes in a delicate balance among the vertical external forces described above. That is, when the settlement of the ground is larger than the settlement of the steel sheet pile, a downward frictional force acts. On the contrary, when the amount of settlement of the ground is small, an upward frictional force acts. As described above, it is difficult to design a sheet pile wall in a strict sense unless the settlement amount of the ground and the settlement amount of the steel sheet pile are predicted in detail. Therefore, considering the condition of the ground, we decided to simplify it based on the following assumptions. -If the sandy soil is thickly distributed on the surface of the ground below the embankment, the lateral flow due to the embankment hardly occurs, so no horizontal external force or deformation is considered.・ According to the observation results after the embankment in the Kumamoto Plain, it has been found that the neutral point is located at half the soft layer thickness on both the embankment side and inside the embankment. It is assumed that frictional force is generated.・ Since the subsidence in the embankment has the same amount of settlement as steel sheet pile,
No downward friction force shall be generated below the neutral point inside the embankment. FIG. 4 shows a simplified schematic diagram of the external force created based on the above assumptions. Of these external forces, the pushing force F and the frictional force f can be calculated from the results of the indoor soil test, and R can be calculated from the N value, the cone penetration test result, and the like.
【００２２】このような検討結果に基づき、前記熊本平
野の白川の堤防で試験施工を実施した。軟弱層の厚さは
４５ｍであり、沈下中立点の深度は２０ｍであったの
で、着底鋼矢板の支持層への根入れを１ｍとし、鋼矢板
頭部を地表より０．５ｍの深度に設定すると、着底鋼矢
板長は４５．５ｍ、フローティング鋼矢板長は１９．５
ｍになる。この場合の着底鋼矢板の間隔Ｎは、次式で求
められる（図５参照）。 Ｆ2 ＋ＮＦ1 ＝Ｒ＋Σｆ2 ＋ＮΣｆ1 ここで、Ｎ ：フローティング鋼矢板の枚数 Ｆ1 ：フローティング鋼矢板に作用する押し込み力 Ｆ2 ：着底鋼矢板に作用する押し込み力 ｆ1 ：フローティング鋼矢板に作用する摩擦力 ｆ2 ：着底鋼矢板に作用する摩擦力 Ｒ ：着底鋼矢板下端の支持力Based on the results of the examination, a test construction was carried out at the Shirakawa embankment in the Kumamoto Plain. The thickness of the soft layer was 45 m, and the depth of the neutral point of settlement was 20 m. Therefore, the depth of the steel sheet pile was set at 1 m, and the head of the steel sheet pile was set at 0.5 m below the surface of the ground. When set, the bottom steel sheet pile length is 45.5m and the floating steel sheet pile length is 19.5m.
m. In this case, the interval N between the bottomed steel sheet piles is obtained by the following equation (see FIG. 5). F 2 + NF 1 = R + Σf 2 + NΣf 1 where N: number of floating steel sheet piles F 1 : pushing force acting on floating steel sheet pile F 2 : pushing force acting on bottomed steel sheet pile f 1 : acting on floating steel sheet pile F 2 : Friction force acting on the bottomed steel sheet pile R: Supporting force at the bottom of the bottomed steel sheet pile
【００２３】上記の設計例では、図２に示すように、１
枚の着底鋼矢板２２に対して７枚のフローティング鋼矢
板２４の組み合わせになっている。このような本発明工
法では、従来の着底型の鋼矢板工法に比べて約４０〜６
０％の工事費で施工が可能であった。また、試験施工後
の中間的な動態観測結果でも、明瞭な沈下の縁切り効果
が確認できた。In the above design example, as shown in FIG.
A combination of seven floating steel sheet piles 24 with one bottomed steel sheet pile 22 is provided. In the method of the present invention, about 40 to 6 times as compared with the conventional bottomed steel sheet pile method.
The construction was possible with 0% construction cost. Intermediate dynamic observation results after the test execution also confirmed a clear settlement margin effect.
【００２４】勿論、地盤の状態や、使用する着底支柱な
どに応じて、着底支柱１本に対するフローティング鋼矢
板の枚数は変化するが、通常３〜１０枚程度の割合で組
み合わせる。着底支柱は、鋼矢板に限らず任意の構造の
支柱を用いてよい。フローティング鋼矢板の断面形状も
任意であってよい。Of course, the number of floating steel sheet piles per one bottom support pillar varies depending on the condition of the ground, the bottom support used, and the like. The bottom support column is not limited to the steel sheet pile, and a support column having an arbitrary structure may be used. The sectional shape of the floating steel sheet pile may be arbitrary.
【００２５】[0025]
【発明の効果】本発明は上記のように、着底支柱を間隔
をおいて配設し、その間に複数のフローティング鋼矢板
を並設して壁面を形成し、それらの頭部で結合一体化し
た構造としたことにより、十分な沈下の縁切り効果が生
じ、しかも施工が容易で、工期の短縮並びに工事費用の
大幅な削減が可能となる。As described above, according to the present invention, bottom support columns are arranged at intervals, a plurality of floating steel sheet piles are arranged side by side therebetween to form a wall surface, and their heads are joined and integrated. With such a structure, a sufficient settlement effect of the settlement is generated, and the construction is easy, and the construction period can be shortened and the construction cost can be significantly reduced.
【図１】本発明に係る沈下縁切り矢板壁の一実施例を示
す説明図。FIG. 1 is an explanatory view showing one embodiment of a sunk edge cutting sheet pile wall according to the present invention.
【図２】その設計例の詳細図。FIG. 2 is a detailed view of the design example.
【図３】鋼矢板に作用する外力の模式図。FIG. 3 is a schematic view of an external force acting on a steel sheet pile.
【図４】鋼矢板に作用する外力の簡略化した模式図。FIG. 4 is a simplified schematic diagram of an external force acting on a steel sheet pile.
【図５】本発明に係る沈下縁切り矢板壁に作用する力の
模式図。FIG. 5 is a schematic view of a force acting on a squatting edge sheet pile wall according to the present invention.
１０ 軟弱層 １２ 堤防 １４ 支持層 ２０ 沈下縁切り矢板壁 ２２ 着底鋼矢板 ２４ フローティング鋼矢板 ２６ 連結部材 DESCRIPTION OF SYMBOLS 10 Soft layer 12 Embankment 14 Support layer 20 Subsidence edge cut sheet pile wall 22 Bottom steel sheet pile 24 Floating steel sheet pile 26 Connecting member
───────────────────────────────────────────────────── フロントページの続き (72)発明者 望月 達也 熊本県熊本市西原１丁目12−１ 建設省九 州地方建設局熊本工事事務所内 (72)発明者 田上 敏博 熊本県熊本市西原１丁目12−１ 建設省九 州地方建設局熊本工事事務所内 (72)発明者 塚元 伸一 東京都千代田区九段北４丁目２番６号 応 用地質株式会社内 Ｆターム(参考） 2D049 EA03 FB03 FB12 FB13 FB14 FC03 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tatsuya Mochizuki 1-12-1 Nishihara, Kumamoto City, Kumamoto Prefecture Inside the Kumamoto Construction Office, Kyushu Regional Construction Bureau, Ministry of Construction (72) Inventor Toshihiro Tagami 1-12 Nishihara Nishihara, Kumamoto City, Kumamoto Prefecture -1 Kumamoto Construction Office, Kyushu Regional Construction Bureau, Ministry of Construction (72) Inventor Shinichi Tsukamoto 4-62 Kudankita, Chiyoda-ku, Tokyo Applied Geological Co., Ltd. F-term (reference) 2D049 EA03 FB03 FB12 FB13 FB14 FC03
Claims (6)
する着底支柱が間隔をおいて配設され、該着底支柱の間
に軟弱層の途中まで挿入される単一もしくは複数のフロ
ーティング鋼矢板が設置されることで壁面が形成され、
着底支柱及びフローティング鋼矢板が、それらの頭部で
結合一体化されていることを特徴とする沈下縁切り矢板
壁。1. A bottom strut that extends through a soft layer and reaches a support layer in the ground is disposed at intervals, and a single or a plurality of bottom struts are inserted between the bottom struts and halfway through the soft layer. The wall is formed by installing the floating steel sheet pile,
A submerged edged sheet pile wall, wherein the bottom support and the floating steel sheet pile are joined and integrated at their heads.
沈下する地層以深まで挿入されている請求項１記載の沈
下縁切り矢板壁。2. The submerged edge-cut sheet pile wall according to claim 1, wherein the floating steel sheet pile is inserted deeper than a submerged stratum in the soft layer.
矢板３〜１０枚の割合で組み合わされている請求項１又
は２記載の沈下縁切り矢板壁。3. The submerged edge cut sheet pile wall according to claim 1, wherein 3 to 10 floating steel sheet piles are combined with one bottom support column.
断面形状の着底鋼矢板からなる請求項１乃至３のいずれ
かに記載の沈下縁切り矢板壁。4. The submerged edge-cut sheet pile wall according to claim 1, wherein the bottom support column is made of a bottom steel sheet pile having the same cross-sectional shape as the floating steel sheet pile.
厚さの４０〜８０％とする請求項４記載の沈下縁切り矢
板壁。5. The submerged perforated sheet pile wall according to claim 4, wherein the length of the floating steel sheet pile is 40 to 80% of the thickness of the soft layer.
部の両側に、棒状の連結部材を当接し連結ボルトを用い
て締結すると共に、両側に位置する連結部材の間に結合
部材を間隔をおいて介在させて連結ボルトを用いて締結
することにより、壁面全体を結合一体化した請求項４又
は５記載の沈下縁切り矢板壁。6. A rod-shaped connecting member is abutted on both sides of the head of the bottomed steel sheet pile and the head of the floating steel sheet pile and fastened by using connecting bolts, and a connecting member is provided between the connecting members located on both sides. The submerged edge-cut sheet pile wall according to claim 4 or 5, wherein the entire wall surface is joined and integrated by being interposed and fastened using a connecting bolt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000139147A JP2001317043A (en) | 2000-05-11 | 2000-05-11 | Sheet-pile wall for separation against settlement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000139147A JP2001317043A (en) | 2000-05-11 | 2000-05-11 | Sheet-pile wall for separation against settlement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001317043A true JP2001317043A (en) | 2001-11-16 |
Family
ID=18646644
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000139147A Withdrawn JP2001317043A (en) | 2000-05-11 | 2000-05-11 | Sheet-pile wall for separation against settlement |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004108078A (en) * | 2002-09-20 | 2004-04-08 | Kajima Corp | Construction method for underwater shaft, underwater shaft, connection method for shaft and adit, and pit structure |
| JP2008031722A (en) * | 2006-07-28 | 2008-02-14 | Railway Technical Res Inst | Banking structure and reinforcing method of banking structure |
| JP2008303628A (en) * | 2007-06-08 | 2008-12-18 | Nippon Shokubai Co Ltd | Friction reducing material |
| JP2011214252A (en) * | 2010-03-31 | 2011-10-27 | Sumitomo Metal Ind Ltd | Structure for reinforcing embankment |
| JP2012007394A (en) * | 2010-06-25 | 2012-01-12 | Sumitomo Metal Ind Ltd | Embankment reinforcement structure |
| JP2013014962A (en) * | 2011-07-05 | 2013-01-24 | Nippon Steel & Sumitomo Metal | Structure for reinforcing levee |
| JP2017197951A (en) * | 2016-04-27 | 2017-11-02 | 戸田建設株式会社 | Countermeasure wall against drawn-in subsidence and construction method thereof |
-
2000
- 2000-05-11 JP JP2000139147A patent/JP2001317043A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004108078A (en) * | 2002-09-20 | 2004-04-08 | Kajima Corp | Construction method for underwater shaft, underwater shaft, connection method for shaft and adit, and pit structure |
| JP2008031722A (en) * | 2006-07-28 | 2008-02-14 | Railway Technical Res Inst | Banking structure and reinforcing method of banking structure |
| JP2008303628A (en) * | 2007-06-08 | 2008-12-18 | Nippon Shokubai Co Ltd | Friction reducing material |
| JP2011214252A (en) * | 2010-03-31 | 2011-10-27 | Sumitomo Metal Ind Ltd | Structure for reinforcing embankment |
| JP2012007394A (en) * | 2010-06-25 | 2012-01-12 | Sumitomo Metal Ind Ltd | Embankment reinforcement structure |
| JP2013014962A (en) * | 2011-07-05 | 2013-01-24 | Nippon Steel & Sumitomo Metal | Structure for reinforcing levee |
| JP2017197951A (en) * | 2016-04-27 | 2017-11-02 | 戸田建設株式会社 | Countermeasure wall against drawn-in subsidence and construction method thereof |
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