JP4354077B2 - Pile loading test method and loading test apparatus - Google Patents

Pile loading test method and loading test apparatus Download PDF

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JP4354077B2
JP4354077B2 JP2000069936A JP2000069936A JP4354077B2 JP 4354077 B2 JP4354077 B2 JP 4354077B2 JP 2000069936 A JP2000069936 A JP 2000069936A JP 2000069936 A JP2000069936 A JP 2000069936A JP 4354077 B2 JP4354077 B2 JP 4354077B2
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pile
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reaction force
loading test
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JP2001254349A (en
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雅路 青木
芳雄 平井
秀規 北折
正夫 丸岡
敏明 土屋
良久 安富
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Takenaka Corp
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  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
  • Placing Or Removing Of Piles Or Sheet Piles, Or Accessories Thereof (AREA)
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Description

【０００１】
【発明の属する技術分野】
この発明は、地中に構築した試験杭について、その鉛直方向上方に一連の配置で設けた反力杭を利用して鉛直交番載荷試験を行う、杭の載荷試験方法及び載荷試験装置の技術分野に属する。
【０００２】
【従来の技術】
近年、大地震時における基礎の保有耐力の評価に関する重要性が増加している。塔状比の大きな建築物では、地震時に基礎杭に大きな押込み力及び引抜き力が作用し、建物が浮き上がったり、更には転倒する可能性が考えられる。このような建物の基礎設計では、杭の押込み力や引抜き力に対する支持力を測定するために、以下に示す（１）〜（３）の杭の載荷試験が実施される。
【０００３】
（１）杭の先端及び杭を切断した中間部に、押込み力のみ作用するジャッキを設置して載荷することにより、杭の押込み力に対する支持力を測定する方法（特許第２５５１８００号公報、特公平６−４８２２４号公報、特公平６−６３８７９号公報に記載）。
【０００４】
（２）図５に示すように、試験杭１の複数箇所を鉛直方向の伸縮が可能に分割し、上下に相隣り合う杭の伸縮（分割）箇所に押込み力のみ作用することができるジャッキａ、ｂ、ｃを設置し、分割杭１Ａの周面摩擦力を反力にして、ジャッキａを載荷すると同時に、ジャッキｂを除荷して分割杭１Ｂに押込み力を作用する場合と、ジャッキｂを載荷すると同時に、ジャッキａを除荷して、分割杭１Ｂに引抜き力を作用する場合とを交互に行う鉛直交番載荷試験を行って支持力を測定する方法（特許第２６９４５１０号公報に記載）。
【０００５】
（３）距離をあけて並立する２本の反力杭の杭頭を反力梁で連結し、前記２本の反力杭の中間部位に構築された試験杭の杭頭と前記反力梁とを押込み力のみ作用するジャッキで連結し、更に試験杭の先端部にもジャッキを設け、前記２箇所のジャッキによる載荷と除荷を、載荷試験の内容によって使い分け、載荷方向一定又は鉛直交番載荷試験を行って支持力を測定する方法（特開平７−１９９７３号公報に記載）。
【０００６】
【本発明が解決しようとする課題】
上記の従来技術（１）は、押込み力のみ作用するジャッキが１箇所にだけ設置されているので、試験杭の押込み力に対する支持力しか測定できない。
【０００７】
従来技術（２）は、鉛直交番載荷試験を行うことができるが、ジャッキが押込み力しか作用しないので、最低２箇所以上にジャッキを設置する必要があり、試験杭１を分割しなくてならず、実際に使用される状態の杭を用いて載荷試験を行うことができない。また、中間の分割杭１Ｂは、鉛直交番載荷試験を行うことはできるが、上側の分割杭１Ａと下側の分割杭１Ｃは、載荷方向一定の試験しか行うことができない。また、ジャッキを分割杭の各伸縮箇所に設ける必要があり、作業が煩雑になり、コストが嵩む。加えて、鉛直交番載荷試験を行うには、ジャッキａとジャッキｂを連動して制御する必要があり、試験の自由度が狭くなる。
【０００８】
従来技術（３）は、実際に使われる状態の試験杭を用いて鉛直交番載荷試験を行うことはできるが、それを除くと従来技術（２）と同様の問題がある。また、反力杭や反力梁を構築する必要があり、載荷試験装置が大がかりになり、試験工程が長くなり、コストが嵩む。
【０００９】
従って、本発明の目的は、実際に使用される状態の試験杭を用いて試験することができ、構成が簡単で、試験の自由度を広げることができ、更には試験工程の短縮及びコストの削減に寄与する杭の載荷試験方法及び載荷試験装置を提供することである。
【００１０】
【課題を解決するための手段】
上述した課題を解決するための手段として、請求項１に記載した発明に係る杭の載荷試験方法は、
地中に構築した試験杭１をその鉛直方向上方に設けた反力杭５の周面摩擦力を利用して載荷試験を行う杭の載荷試験方法において、
前記試験杭１及び前記反力杭５にそれぞれ鉄骨等の荷重伝達部材２、６を一体的に鉛直方向に設け、前記試験杭１側の荷重伝達部材２の上端部と前記反力杭５側の荷重伝達部材６の下端部との間に間隔をあけた空洞部８を設け、
前記空洞部８内に、押込み力及び引抜き力を交互に作用する押し引き兼用ジャッキ４を、そのシリンダ４ａ側とピストンロッド４ｅ側をそれぞれ前記試験杭１及び前記反力杭５の荷重伝達部材２、６と結合して設置し、
前記押し引き兼用ジャッキ４による押込み力と引抜き力を前記反力杭５に反力をとって前記試験杭１へ伝達して鉛直交番載荷試験を行うことを特徴とする。
【００１１】
請求項２に記載した発明は、請求項１に記載した発明に係る杭の載荷試験装置において、
試験杭１の杭頭部及び下端部にそれぞれ変位ロッド１２ａ、１２ｂの下端を止着し、前記変位ロッド１２ａ、１２ｂの上端部に変位計１１を設けて、鉛直交番載荷試験による試験杭１の上下方向変位を前記変位計１１により測定することを特徴とする。
【００１２】
請求項３に記載した発明に係る杭の載荷試験装置は、
地中に構築した試験杭１をその鉛直方向上方に設けた反力杭５の周面摩擦力を利用して載荷試験を行う杭の載荷試験装置において、
前記試験杭１及び前記反力杭５にそれぞれ鉄骨等の荷重伝達部材２、６が一体的に鉛直方向に設けられ、前記試験杭１側の荷重伝達部材２の上端部及び前記反力杭５側の荷重伝達部材６の下端部との間に間隔をあけた空洞部８が設けられ、
前記空洞部８内に、押込み力及び引抜き力を交互に作用する押し引き兼用ジャッキ４が、そのシリンダ４ａ側とピストンロッド４ｅ側をそれぞれ前記試験杭１及び前記反力杭５の荷重伝達部材２、６と結合して設置されており、
前記押し引き兼用ジャッキ４による押込み力と引抜き力を前記反力杭５に反力をとって前記試験杭１へ伝達して鉛直交番載荷試験を行うことを特徴とする。
【００１３】
請求項４に記載した発明は、請求項３に記載した発明に係る杭の載荷試験装置において、
試験杭１の杭頭部及び下端部にそれぞれ二重管構造による変位ロッド１２ａ、１２ｂの下端が止着され、鉛直方向上方へ地上まで立ち上げた前記変位ロッド１２ａ、１２ｂの上端部に変位計１１が設けられ、鉛直交番載荷試験による試験杭１の上下方向変位が前記変位計１１により測定されることを特徴とする。
【００１４】
請求項５に記載した発明は、請求項３又は４に記載した発明に係る杭の載荷試験装置において、
押し引き兼用ジャッキ４は、油圧式複動シリンダ等の伸縮運動が可能なジャッキであり、そのピストン４ｂが略中立状態を維持して設置されていることを特徴とする。
【００１５】
請求項６に記載した発明は、請求項３〜５のいずれか一に記載した発明に係る杭の載荷試験装置において、
反力杭５は、載荷試験に必要な周面摩擦力を確保できるように杭径が太く形成され、又は杭外周に多数の抵抗溝が設けられていることを特徴とする。
【００１６】
請求項７に記載した発明は、請求項３〜６のいずれか一に記載した発明に係る杭の載荷試験装置において、
空洞部には、安定液等の孔壁崩壊を防止するための液体が注入されていることを特徴とする。
【００１７】
【本発明の実施形態及び実施例】
図１は、請求項３〜５に記載した発明に係る杭の載荷試験装置の実施形態を概念的に示している。この載荷試験装置は、地中に構築した試験杭１を、その鉛直方向上方に一連の配置で設けた反力杭５の周面摩擦力を利用して鉛直交番載荷試験を行うものであり、試験杭１の押込み力及び引抜き力に対する支持力を測定する場合に好適に実施される。
【００１８】
前記載荷試験装置は、図２に構造詳細を示したように、試験杭１及び反力杭５にそれぞれ、鉛直方向に一連に同心の配置で荷重伝達部材としての鉄骨２及び６がコンクリート中に埋設固定して一体的に設けられている。前記試験杭１の鉄骨２の上端部、及び前記反力杭５の鉄骨６の下端部にそれぞれ間隔をあけて、上下２枚ずつの連結板３、３及び７、７が略水平方向に設けられている。反力杭５側の一つである下位の連結板７は、反力杭５の下端部のコンクリート仕切り板を兼ねている。そのため前記連結板７より上方の杭孔壁面との間隙には、コンクリートが空洞部８へ流れ込まないように上部コンクリートを仕切るパッカー１４が設けられている。かくして下方反力杭５の下端と試験杭１の上端との間には、下記の押し引き兼用ジャッキ４を設置するのに必要な大きさ（高さ寸法）の間隔をあけた空洞部８が形成されている。
【００１９】
前記上下の連結板３と７の間に、押込み力及び引抜き力を交互に作用する押し引き兼用ジャッキ４が設置されている。図示例の場合、押し引き兼用ジャッキ４のシリンダ４ａ及びそのロッド４ｆが反力杭５の連結板７に結合されている。他方、ピストンロッド４ｅは試験杭１の連結板３とナット１３により結合されている。
【００２０】
前記押し引き兼用ジャッキ４には、複動シリンダ式の油圧ジャッキが用いられ、そのピストン４ｂが中立状態を維持して設置されている（請求項５に記載の発明）。そして、前記押し引き兼用ジャッキ４のシリンダ４ａの下端と、試験杭１側の上方部のナット１３との間に、試験杭１の押し引きに必要な距離（ストローク）をあけた空洞部８が設けられている。
【００２１】
上記構成により、前記押し引き兼用ジャッキ４の押込み力及び引抜き力は、上下の連結板３及び７を介して鉄骨２及び６へ伝達され、更に鉄骨２及び６から前記試験杭１及び反力杭５へ伝達される。
【００２２】
前記押し引き兼用ジャッキ４には、地上に設置された油圧ポンプ９と油圧制御回路を含む油圧ユニットの往路又は復路となるホース１０ａ、復路又は往路となるホース１０ｂが、ピストン４ｂの上側及び下側の油室４ｃ、４ｄに接続され、前記ポンプ９と油圧制御回路を含む油圧ユニットの操作により押し引き兼用ジャッキ４を駆動し、反力杭５の周面摩擦力を反力にして、押込み力及び引込み力を前記試験杭１へ伝達して鉛直交番載荷試験が行われる。
【００２３】
なお、前記試験杭１の杭頭及び下端部には、それぞれ二重管構造による変位ロッド１２ａ、１２ｂの下端が止着され、鉛直方向上方へ地上まで立ち上げた前記変位ロッド１２ａ、１２ｂの頭部に変位計１１、１１が設けられ、鉛直交番載荷試験による試験杭１の上下方向変位を前記変位計１１、１１により測定できる構成とされている（請求項４に記載の発明）。
【００２４】
上記のように構成された請求項３〜５に記載した杭の載荷試験装置を用いて、請求項１及び２に記載した発明に係る杭の載荷試験方法を行う。
【００２５】
前記載荷試験方法は、前記押し引き兼用ジャッキ４による押込み力及び引込み力を前記試験杭１へ伝達して鉛直交番載荷試験を行う。
【００２６】
具体的には、試験杭１に押込み力を伝達する場合は、上記ポンプ９と油圧制御回路を含む油圧ユニットを操作して、上側の油室４ｃに作動油を注入すると、上記載荷試験装置は、反力杭５へ引抜き力を伝達すると同時に、試験杭１へ押込み力を伝達する。前記反力杭５は、試験杭１の支持力よりも大きな支持力を発揮する形状とされているため、同反力杭５へ伝達した引抜き力は、反力杭５の周面摩擦力が反力となり相殺され、試験杭１に押込み力を伝達する。それに伴って、ピストン４ｂが下降すると共に試験杭１を地中に押込み、その変位量だけ下側の油室４ｄの作動油を、下側の油室４ｄに接続した復路ホース１０ｂへ押し出して排出する。
【００２７】
逆に、試験杭１に引抜き力を伝達する場合は、前記ポンプ９と油圧制御回路を含む油圧ユニットを操作して、下側の油室４ｄに作動油を注入すると、上記載荷試験装置は、反力杭５へ押込み力を伝達すると同時に、試験杭１へ引抜き力を伝達する。前記反力杭５へ伝達した押込み力は、反力杭５の周面摩擦力が反力となり相殺され、試験杭１に引抜き力が作用する。それに伴って、ピストン４ｂが上昇すると共に試験杭１を地中から引抜き、その変位量だけ上側の油室４ｃの作動油を、上側の油室４ｃに接続した復路ホース１０ａへ押し出して排出する。
【００２８】
上記した押込み力及び引抜き力を試験杭１に伝達する手段を交互に繰り返して、鉛直交番載荷試験を行う。
【００２９】
前記鉛直交番載荷試験による試験杭１の変位量を、同試験杭１の杭頭及び下端部に止着された変位ロッド１２ａ及び１２ｂが、上昇及び下降して、その変位量を変位計１１、１１により測定する（請求項２に記載の発明）。
【００３０】
以上により、前記ポンプ９と油圧制御回路を含む油圧ユニットを操作することによって押し引き兼用ジャッキ４が押込み力及び引抜き力を交互に試験杭１に作用することができるので、同押し引き兼用ジャッキ４を１箇所に設けるだけで、鉛直交番載荷試験を行うことができる。
【００３１】
また、前記載荷試験装置は、反力杭５の反力を利用して、試験杭１に押込み力及び引抜き力を伝達するため、載荷試験装置が大がかりな構造にはならない。
【００３２】
なお、上記実施形態では、前記反力杭５の形状を、図１及び図２に示すように、筒状の反力杭を用いているが、大きな載荷荷重を試験杭１に伝達する場合は、図３及び図４に示すように、反力杭５の杭径を大きくしたり、杭外周に多数の抵抗溝を設けても良い（請求項６に記載した発明）。
【００３３】
また、上記実施形態では、上記空洞部８に何も入れられていないが、これに限らず、安定液等の孔壁崩壊を防止するための液体が注入されていても良い（請求項７に記載した発明）。
【００３４】
更には、上記実施形態では、反力杭５の下端部を形成する下側の連結板７は、コンクリート仕切り板を兼用する共通部材とされているが、これに限らず、別部材とされていても良い。
【００３５】
加えて、上記実施形態では、鉄骨２及び６は試験杭１及び反力杭５のコンクリート内に埋設固定されているが、コンクリート仕切板に溶接等の手段で固定されていても良い。また、ロッド４ｅ、４ｆは、上下の連結板３、７にナット１３で固定されているが、これに限らず、溶接等の手段で固定されていても良い。
【００３６】
【本発明が奏する効果】
請求項１〜７に記載した発明に係る杭の載荷試験方法及び載荷試験装置は、押込み力及び引抜き力を交互に作用することができる押し引き兼用ジャッキを用いることによって、１箇所に設けるだけで、鉛直交番載荷を極めて簡単に、実際に使われる状態の試験杭を用いる試験を行うことができると共に、試験の自由度を広くすることができる。更に、反力杭の周面摩擦力による反力を利用して、試験杭に押込み力及び引抜き力を伝達するため、載荷試験装置が大がかりな構造にはならず、簡単な構成の載荷試験装置を用いることによって、試験工程の短縮及びコストの削減に寄与することできる。
【図面の簡単な説明】
【図１】本発明の実施形態を示した立面図である。
【図２】本発明の実施形態において用いられる押し引き兼用ジャッキの詳細を示した立面図である。
【図３】本発明の他の実施形態を示した立面図である。
【図４】本発明の他の実施形態を示した立面図である。
【図５】従来の技術を示した立面図である。
【符号の説明】
１ 試験杭
２、６ 鉄骨
３、７ 連結板
４ 押し引き兼用ジャッキ
５ 反力杭
８ 空洞部
９ ポンプ
１０ａ 往路又は復路となるホース
１０ｂ 復路又は往路となるホース
１１ 変位計
１２ａ、１２ｂ 変位ロッド
１３ ナット
１４ 上部コンクリート止めパッカー[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a test method for a pile and a technical field of a load test apparatus that performs a lead orthogonal number loading test using a reaction force pile provided in a series of arrangements in the vertical direction above a test pile constructed in the ground. Belonging to.
[0002]
[Prior art]
In recent years, the importance of evaluating the strength of foundations during a large earthquake has increased. In buildings with a large tower ratio, there is a possibility that a large pushing force and pulling force will act on the foundation pile at the time of an earthquake, and the building may rise or fall over. In the basic design of such a building, the following pile loading tests (1) to (3) are performed in order to measure the supporting force against the pushing force and pulling force of the pile.
[0003]
(1) A method of measuring the supporting force against the indentation force of the pile by installing a jack that acts only on the indentation force at the tip of the pile and the intermediate part where the pile is cut (Japanese Patent No. 2551800, 6-48224 and JP-B-6-63879).
[0004]
(2) As shown in FIG. 5, the jack a which divides | segments several places of the test pile 1 so that expansion | extension of a perpendicular direction is possible, and can act only on pushing force to the expansion-contraction (division | segmentation) location of the pile which adjoins up and down. , B, and c, the peripheral frictional force of the divided pile 1A is set as a reaction force, and the jack a is loaded. At the same time, the jack b is unloaded and a pushing force is applied to the divided pile 1B. At the same time as unloading the jack a and performing a lead orthogonal number loading test in which the pulling force is applied alternately to the divided pile 1B and measuring the supporting force (described in Japanese Patent No. 2694510) .
[0005]
(3) The pile heads of two reaction force piles arranged side by side at a distance are connected by a reaction beam, and the pile heads of the test pile and the reaction beam built at an intermediate part of the two reaction force piles Are connected with a jack that acts only on the pushing force, and a jack is also provided at the tip of the test pile. Loading and unloading by the two jacks are used depending on the content of the loading test, and the loading direction is constant or lead orthogonal loading A method of performing a test and measuring the supporting force (described in Japanese Patent Laid-Open No. 7-19933).
[0006]
[Problems to be solved by the present invention]
In the above prior art (1) , only the supporting force for the indentation force of the test pile can be measured because the jack that acts only for the indentation force is installed in only one place.
[0007]
Prior art (2) can perform a lead orthogonal number loading test, but since the jack only acts on the indentation force, it is necessary to install the jack in at least two places, and the test pile 1 must be divided. can not and TURMERIC rows loading test using actual states used are piles. Further, the intermediate divided pile 1B can perform a lead orthogonal number loading test, but the upper divided pile 1A and the lower divided pile 1C can perform only a test with a constant loading direction. Moreover, it is necessary to provide a jack in each expansion-contraction location of a division | segmentation pile, and an operation | work will become complicated and cost will increase. In addition, in order to perform the lead orthogonal number loading test, it is necessary to control the jack a and the jack b in conjunction with each other, which reduces the degree of freedom of the test.
[0008]
Although the prior art (3) can perform the lead orthogonal number loading test using the test pile actually used, there is the same problem as the prior art (2) except for that. In addition, it is necessary to construct a reaction force pile and a reaction force beam, and the loading test apparatus becomes large, the test process becomes longer, and the cost increases.
[0009]
Therefore, the object of the present invention can be tested using test piles in actual use, has a simple configuration, can increase the degree of freedom of testing, and further shortens the test process and reduces costs. It is to provide a pile loading test method and a loading test apparatus that contribute to reduction.
[0010]
[Means for Solving the Problems]
As a means for solving the above-described problem, a pile loading test method according to the invention described in claim 1 is:
In the pile loading test method of performing a loading test using the circumferential frictional force of the reaction force pile 5 provided in the vertical direction above the test pile 1 constructed in the ground,
The test pile 1 and the reaction force pile 5 are each integrally provided with load transmission members 2 and 6 such as steel frames in the vertical direction, and the upper end portion of the load transmission member 2 on the test pile 1 side and the reaction force pile 5 side. A hollow portion 8 is provided between the lower end portion of the load transmitting member 6 and a space between them ;
In the hollow portion 8, a push / pull jack 4 that alternately applies a pushing force and a pulling force, and the load transmitting member 2 of the test pile 1 and the reaction force pile 5 on the cylinder 4a side and the piston rod 4e side, respectively. , 6 installed,
The pushing force and pulling force by prior SL push-pull combined jack 4 is transmitted the to the test pile 1 by taking the reaction force to the reaction force pile 5 and performs vertical cyclic loading test.
[0011]
The invention described in claim 2 is a pile loading test apparatus according to the invention described in claim 1,
Each displacement rod 12a to the pile head end and the lower end of the test pile 1, the lower end of 12b and secured, the displacement rod 12a, the displacement meter 11 is provided on the upper portion of 12b, by vertical cyclic loading test of test pile 1 The displacement in the vertical direction is measured by the displacement meter 11.
[0012]
The pile loading test apparatus according to the invention described in claim 3 is:
In the pile loading test apparatus which performs the loading test using the circumferential frictional force of the reaction force pile 5 provided in the vertical direction above the test pile 1 constructed in the ground,
The test pile 1 and the reaction force pile 5 are each integrally provided with a load transmission member 2, 6 such as a steel frame in the vertical direction, the upper end of the load transmission member 2 on the test pile 1 side and the reaction force pile 5. A cavity 8 is provided with a gap between the lower end of the load transmitting member 6 on the side ,
A push / pull jack 4 that alternately exerts a pushing force and a pulling force in the cavity 8 has a load transmitting member 2 for the test pile 1 and the reaction force pile 5 on the cylinder 4a side and the piston rod 4e side, respectively. , 6 and installed ,
The pushing force and pulling force by prior SL push-pull combined jack 4 is transmitted the to the test pile 1 by taking the reaction force to the reaction force pile 5 and performs vertical cyclic loading test.
[0013]
The invention described in claim 4 is a pile loading test apparatus according to the invention described in claim 3,
Displacement rod 12a by the respective double pipe structure in pile head end and the lower end of the test pile 1, the lower end of 12b is secured, said displacement rod 12a launched to the ground vertically upward, displacement gauge to the upper end of the 12b 11 is provided, and the displacement in the vertical direction of the test pile 1 by the lead orthogonal number loading test is measured by the displacement meter 11.
[0014]
The invention described in claim 5 is a pile loading test apparatus according to the invention described in claim 3 or 4,
Push-pull combined jack 4 is a jack capable of expansion and contraction, such as a hydraulic double-acting cylinder, it characterized that the piston 4b is provided to maintain a substantially neutral state.
[0015]
The invention described in claim 6 is a pile loading test apparatus according to any one of claims 3 to 5,
Hanchikarakui 5 is formed thicker pile diameter so as to ensure the peripheral surface frictional force required for loading test, or a number of resistors groove, characterized in that provided in Kuigaishu.
[0016]
The invention described in claim 7 is a pile loading test apparatus according to any one of claims 3 to 6,
A liquid for preventing collapse of the hole wall such as a stable liquid is injected into the hollow portion.
[0017]
[Embodiments and Examples of the Invention]
FIG. 1 conceptually shows an embodiment of a pile loading test apparatus according to the inventions described in claims 3 to 5. This loading test apparatus performs a lead orthogonal number loading test using the circumferential frictional force of the reaction force pile 5 provided in a series of arrangements on the test pile 1 built in the ground in the vertical direction. It is suitably implemented when measuring the supporting force against the pushing force and pulling force of the test pile 1.
[0018]
As shown in the structural details in FIG. 2, the load test apparatus described above has steel frames 2 and 6 as load transmission members in the concrete in a series of concentric arrangements in the vertical direction on the test pile 1 and the reaction force pile 5, respectively. It is embedded and fixed integrally. Two upper and lower connecting plates 3, 3, 7, and 7 are provided in a substantially horizontal direction at intervals between the upper end of the steel frame 2 of the test pile 1 and the lower end of the steel frame 6 of the reaction force pile 5. It has been. The lower connecting plate 7, which is one of the reaction force piles 5, also serves as a concrete partition plate at the lower end of the reaction force pile 5. The gap between the upper pile hole wall face from the connecting plate 7. Therefore, packer 14 concrete partition the upper concrete so prevented from flowing into the hollow portion 8 is provided. Thus, between the lower end of the lower reaction force pile 5 and the upper end of the test pile 1, there is a cavity portion 8 having a gap (height dimension) necessary for installing the following push / pull jack 4. Is formed.
[0019]
Between the upper and lower connecting plates 3 and 7, there is provided a push / pull jack 4 that alternately applies pushing force and pulling force. In the case of the illustrated example, the cylinder 4 a of the push / pull jack 4 and its rod 4 f are coupled to the connecting plate 7 of the reaction force pile 5. On the other hand, the piston rod 4 e is connected to the connection plate 3 of the test pile 1 by a nut 13.
[0020]
A double-acting cylinder type hydraulic jack is used for the push / pull jack 4, and the piston 4b is installed in a neutral state (invention according to claim 5). And the cavity part 8 which opened the distance (stroke) required for pushing and pulling of the test pile 1 between the lower end of the cylinder 4a of the said jack 4 for push / pull and the nut 13 of the upper part by the side of the test pile 1 is. Is provided.
[0021]
With the above configuration, the pushing force and the pulling force of the push / pull jack 4 are transmitted to the steel frames 2 and 6 via the upper and lower connecting plates 3 and 7, and the test pile 1 and the reaction force pile are further transmitted from the steel frames 2 and 6. 5 is transmitted.
[0022]
The push / pull jack 4 includes a hose 10a serving as a forward path or a return path of a hydraulic unit including a hydraulic pump 9 installed on the ground and a hydraulic control circuit, and a hose 10b serving as a return path or a forward path, above and below the piston 4b. Is connected to the oil chambers 4c and 4d, and the push / pull jack 4 is driven by the operation of a hydraulic unit including the pump 9 and a hydraulic control circuit, and the circumferential frictional force of the reaction force pile 5 is used as a reaction force, thereby pushing force And lead-in force is transmitted to the said test pile 1, and a lead orthogonal number loading test is done.
[0023]
It should be noted that the lower ends of the displacement rods 12a and 12b having a double-pipe structure are fixed to the pile head and the lower end of the test pile 1, respectively, and the heads of the displacement rods 12a and 12b raised up to the ground in the vertical direction. Displacement gauges 11 and 11 are provided in the part, and the vertical displacement of the test pile 1 by the lead orthogonal load loading test can be measured by the displacement gauges 11 and 11 (invention according to claim 4).
[0024]
The pile loading test method according to the invention described in claims 1 and 2 is performed using the pile loading test apparatus described in claims 3 to 5 configured as described above.
[0025]
In the load test method described above, the pushing force and the pulling force by the push / pull jack 4 are transmitted to the test pile 1 to perform a lead orthogonal load test.
[0026]
Specifically, when the pushing force is transmitted to the test pile 1, when the hydraulic unit including the pump 9 and the hydraulic control circuit is operated to inject the working oil into the upper oil chamber 4c, the load testing apparatus described above is The pulling force is transmitted to the reaction pile 5 and simultaneously the pushing force is transmitted to the test pile 1. Since the reaction force pile 5 has a shape that exerts a greater support force than the test pile 1, the pulling force transmitted to the reaction force pile 5 is the peripheral friction force of the reaction force pile 5. The reaction force cancels out, and the pushing force is transmitted to the test pile 1. Along with this, the piston 4b descends and the test pile 1 is pushed into the ground, and the hydraulic oil in the lower oil chamber 4d is pushed by the displacement amount to the return hose 10b connected to the lower oil chamber 4d and discharged. To do.
[0027]
Conversely, when transmitting the pulling force to the test pile 1, operating the hydraulic unit including the pump 9 and the hydraulic control circuit to inject the hydraulic oil into the lower oil chamber 4d, The pushing force is transmitted to the reaction force pile 5 and at the same time the pulling force is transmitted to the test pile 1. The pushing force transmitted to the reaction force pile 5 is canceled by the reaction force of the peripheral surface of the reaction force pile 5 acting as a reaction force, and a pulling force acts on the test pile 1. Along with this, the piston 4b rises and the test pile 1 is pulled out from the ground, and the hydraulic oil in the upper oil chamber 4c is pushed out by a displacement amount to the return hose 10a connected to the upper oil chamber 4c and discharged.
[0028]
The means for transmitting the indentation force and the pulling force described above to the test pile 1 is alternately repeated to perform a lead orthogonal number loading test.
[0029]
The displacement rods 12a and 12b fixed to the pile head and the lower end of the test pile 1 are raised and lowered by the displacement amount of the test pile 1 by the lead orthogonal load loading test, and the displacement amount is measured by the displacement meter 11, 11 (Invention of claim 2).
[0030]
By operating the hydraulic unit including the pump 9 and the hydraulic control circuit as described above, the push / pull jack 4 can alternately apply the pushing force and the pulling force to the test pile 1. The lead orthogonal number loading test can be performed only by providing the at one place.
[0031]
In addition, since the load test apparatus described above uses the reaction force of the reaction force pile 5 to transmit the pushing force and the pulling force to the test pile 1, the load test apparatus does not have a large structure.
[0032]
In addition, in the said embodiment, as shown in FIG.1 and FIG.2, although the shape of the said reaction force pile 5 uses the cylindrical reaction force pile, when transmitting a big load load to the test pile 1, 3 and 4, the pile diameter of the reaction force pile 5 may be increased, or a number of resistance grooves may be provided on the outer periphery of the pile (invention described in claim 6).
[0033]
Moreover, in the said embodiment, although nothing is put in the said cavity part 8, the liquid for preventing collapse of hole walls, such as not only this but a stable liquid, may be inject | poured (Claim 7). Described invention).
[0034]
Furthermore, in the above embodiment, the connecting plate 7 of the lower forming the lower end of the Hanchikarakui 5 has been a common member which also serves as a concrete partition plate is not limited thereto, are separate members May be.
[0035]
In addition, in the said embodiment, although the steel frames 2 and 6 are embed | buried and fixed in the concrete of the test pile 1 and the reaction force pile 5, you may be fixed to the concrete partition plate by means, such as welding. Further, the rods 4e and 4f are fixed to the upper and lower connecting plates 3 and 7 by the nut 13, but not limited to this, they may be fixed by means such as welding.
[0036]
[Effects of the present invention]
The pile loading test method and the loading test apparatus according to the inventions described in claims 1 to 7 are provided only in one place by using a jack for pulling and pulling which can alternately act on the pushing force and the pulling force. In addition, it is possible to carry out a test using a test pile in a state where it is actually used, and to increase the degree of freedom of the test. Furthermore, since the indentation force and pull-out force are transmitted to the test pile using the reaction force due to the peripheral frictional force of the reaction force pile, the load test device does not have a large structure, and the load test device has a simple configuration. By using, it is possible to contribute to shortening the test process and reducing costs.
[Brief description of the drawings]
FIG. 1 is an elevational view showing an embodiment of the present invention.
FIG. 2 is an elevation view showing details of the push / pull jack used in the embodiment of the present invention.
FIG. 3 is an elevational view showing another embodiment of the present invention.
FIG. 4 is an elevational view showing another embodiment of the present invention.
FIG. 5 is an elevational view showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Test pile 2, 6 Steel frame 3, 7 Connection board 4 Push / pull jack 5 Reaction force pile 8 Cavity part 9 Pump 10a Hose 10b used as a forward path or a return path Hose 11 used as a return path or a return path Displacement gauges 12a, 12b Displacement rod 13 Nut 14 Upper concrete stop packer

Claims (7)

地中に構築した試験杭を、その鉛直方向上方に設けた反力杭の周面摩擦力を利用して載荷試験を行う杭の載荷試験方法において、
前記試験杭及び前記反力杭にそれぞれ鉄骨等の荷重伝達部材を一体的に鉛直方向に設け、前記試験杭側の荷重伝達部材の上端部と前記反力杭側の荷重伝達部材の下端部との間に間隔をあけた空洞部を設け、
前記空洞部内に、押込み力及び引抜き力を交互に作用する押し引き兼用ジャッキを、そのシリンダ側とピストンロッド側をそれぞれ前記試験杭及び前記反力杭の荷重伝達部材と結合して設置し、
前記押し引き兼用ジャッキによる押込み力と引抜き力を前記反力杭に反力をとって前記試験杭へ伝達して鉛直交番載荷試験を行うことを特徴とする、杭の載荷試験方法。In the pile loading test method of performing a loading test using the circumferential frictional force of the reaction force pile provided in the vertical direction above the test pile built in the ground,
A load transmission member such as a steel frame is integrally provided in the vertical direction in each of the test pile and the reaction force pile, and an upper end portion of the load transmission member on the test pile side and a lower end portion of the load transmission member on the reaction force pile side, A cavity with a gap between
In the hollow portion, a push / pull jack that alternately exerts a pushing force and a pulling force is installed by connecting the cylinder side and the piston rod side with the load transmission members of the test pile and the reaction force pile, respectively.
Characterized in that the pushing force and the pulling force by the previous SL push-pull combined jack and transmits the to the reaction force pile to the test pile taking reaction force performs vertical cyclic loading test, load test method of pile. 試験杭の杭頭部及び下端部にそれぞれ変位ロッドの下端を止着し、前記変位ロッドの上端部に変位計を設けて、鉛直交番載荷試験による試験杭の上下方向変位を前記変位計により測定することを特徴とする、請求項１に記載した杭の載荷試験方法。Each pile head end and the lower end of the test pile was secured to the lower end of the displacement rod, the displacement gauge is provided on the upper end of the displacement rod, measuring the vertical displacement of the test pile by Vertical cyclic loading test by the displacement meter The pile loading test method according to claim 1, wherein the pile loading test method is performed. 地中に構築した試験杭を、その鉛直方向上方に設けた反力杭の周面摩擦力を利用して載荷試験を行う杭の載荷試験装置において、
前記試験杭及び前記反力杭にそれぞれ鉄骨等の荷重伝達部材が一体的に鉛直方向に設けられ、前記試験杭側の荷重伝達部材の上端部及び前記反力杭側の荷重伝達部材の下端部との間に間隔をあけた空洞部が設けられ、
前記空洞部内に、押込み力及び引抜き力を交互に作用する押し引き兼用ジャッキが、そのシリンダ側とピストンロッド側をそれぞれ前記試験杭及び前記反力杭の荷重伝達部材と結合して設置されており、
前記押し引き兼用ジャッキによる押込み力と引抜き力を前記反力杭に反力をとって前記試験杭へ伝達して鉛直交番載荷試験を行うことを特徴とする、杭の載荷試験装置。In the pile loading test device that performs the loading test using the circumferential friction force of the reaction force pile provided in the vertical direction above the test pile built in the ground,
A load transmission member such as a steel frame is integrally provided in the vertical direction in each of the test pile and the reaction force pile, and an upper end portion of the load transmission member on the test pile side and a lower end portion of the load transmission member on the reaction force pile side. A cavity with a gap between
In the hollow portion, a push / pull jack that alternately exerts a pushing force and a pulling force is installed by connecting the cylinder side and the piston rod side to the load transmission members of the test pile and the reaction force pile, respectively. ,
And performing vertical cyclic loading test pushing force and pulling force by prior SL push-pull combined jack and transmits the counter-force pile to the test pile taking a reaction force, pile loading testing apparatus. 試験杭の杭頭部及び下端部にそれぞれ二重管構造による変位ロッドの下端が止着され、鉛直方向上方へ地上まで立ち上げた前記変位ロッドの上端部に変位計が設けられ、鉛直交番載荷試験による試験杭の上下方向変位が前記変位計により測定されることを特徴とする、請求項３に記載した杭の載荷試験装置。The lower end of the displacement rod by respective double pipe structure in pile head end and the lower end of the test pile is secured, the displacement gauge is provided at the upper end of the displacement rod launched to the ground vertically upward, vertically cyclic loading 4. The pile loading test apparatus according to claim 3, wherein the vertical displacement of the test pile by the test is measured by the displacement meter. 押し引き兼用ジャッキは、油圧式複動シリンダ等の伸縮運動が可能なジャッキであり、そのピストンが略中立状態を維持して設置されていることを特徴とする、請求項３又は４に記載した杭の載荷試験装置。Push-pull combined jack is a jack capable of expansion and contraction, such as a hydraulic double-acting cylinder, characterized that the piston is provided to maintain a substantially neutral state, according to claim 3 or 4 Pile loading test equipment. 反力杭は、載荷試験に必要な周面摩擦力を確保できるように杭径が太く形成され、又は杭外周に多数の抵抗溝が設けられていることを特徴とする、請求項３〜５のいずれか一に記載した杭の載荷試験装置。The reaction force pile is formed to have a large pile diameter so that a peripheral frictional force necessary for the loading test can be secured, or a plurality of resistance grooves are provided on the outer periphery of the pile. The pile loading test apparatus described in any one of the above. 空洞部には、安定液等の孔壁崩壊を防止するための液体が注入されていることを特徴とする、請求項３〜６のいずれか一に記載した杭の載荷試験装置。  The pile loading test apparatus according to any one of claims 3 to 6, wherein a liquid for preventing collapse of a hole wall such as a stabilizing liquid is injected into the hollow portion.
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