JPH0137533B2 - - Google Patents
Info
- Publication number
- JPH0137533B2 JPH0137533B2 JP21759384A JP21759384A JPH0137533B2 JP H0137533 B2 JPH0137533 B2 JP H0137533B2 JP 21759384 A JP21759384 A JP 21759384A JP 21759384 A JP21759384 A JP 21759384A JP H0137533 B2 JPH0137533 B2 JP H0137533B2
- Authority
- JP
- Japan
- Prior art keywords
- steel material
- load
- prestress
- grout
- grout material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000463 material Substances 0.000 claims description 60
- 229910000831 Steel Inorganic materials 0.000 claims description 39
- 239000010959 steel Substances 0.000 claims description 39
- 239000011440 grout Substances 0.000 claims description 31
- 238000004873 anchoring Methods 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 5
- 238000010276 construction Methods 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 238000005553 drilling Methods 0.000 description 2
- 239000004519 grease Substances 0.000 description 2
- 239000003673 groundwater Substances 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/80—Ground anchors
- E02D5/808—Ground anchors anchored by using exclusively a bonding material
Landscapes
- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Piles And Underground Anchors (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
この発明はプレストレストグランドアンカー定
着工法に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a prestressed ground anchor fixing method.
この発明が解決すべき問題点
地山を削孔してPC鋼材を挿入し、グラウト材
を注入して定着し、PC鋼材を注入してプレスト
レス力を導入するプレストレストグランドアンカ
ーが開発されている。Problems to be solved by this invention A prestressed ground anchor has been developed in which a prestressed ground anchor is created by drilling a hole in the ground, inserting a prestressing steel material, injecting grout to fix it, and introducing prestressing force by injecting the prestressing steel material. .
このようなプレストレストアンカーにおいて問
題となるのはプレストレス力導入の際に硬化した
グラウト材に生じるクラツクｃである。（第１図）
すなわちPC鋼材ａを緊張した際にPC鋼材ａ外
周に付着したグラウト材ｂも引張られて、グラウ
ト材ｂにPC鋼材ａと直交する方向にクラツクｃ
が生ずるものである。このクラツクｃの幅は鋼材
応力度が1000Kg／cm2の場合約0.1mm、2000Kg／cm2
の場合約0.2mm程度となることが判明している。 A problem with such prestressed anchors is cracks that occur in the hardened grout material when a prestressing force is introduced. (Fig. 1) In other words, when the PC steel material a is tensed, the grout material b attached to the outer periphery of the PC steel material a is also pulled, causing a crack c in the grout material b in the direction orthogonal to the PC steel material a.
This is what happens. The width of this crack c is approximately 0.1mm when the steel stress is 1000Kg/cm 2 and 2000Kg/cm 2
It has been found that the diameter is approximately 0.2 mm.
クラツクｃの幅が0.3mm程度以下である場合に
はクラツクｃ内を地下水が通過せず、クラツクｃ
内がアルカリ化されてPC鋼材ａは錆付かず、そ
れ以上になるとクラツクｃ内を地下水が通過して
クラツクｃ内を中性化してPC鋼材ａを錆付かせ
ることが知られている。PC鋼材ａの錆付きはや
がてPC鋼材ａの破断を招くことがあり、PC鋼材
ａが破断した場合切り離れたPC鋼材ａは定着部
として何ら作用しない。 If the width of crack c is about 0.3mm or less, groundwater will not pass through crack c,
It is known that the inside of the crack C is alkalized and the PC steel material a does not rust, and if the temperature exceeds that level, groundwater passes through the crack c and neutralizes the inside of the crack c, causing the PC steel material a to rust. Rust on the PC steel material a may eventually lead to breakage of the PC steel material a, and when the PC steel material a breaks, the separated PC steel material a does not function as a fixing part at all.
しかし一方第２図及び第３図に示すのは定着部
がそれぞれ5.9ｍと11ｍのアンカーの荷重分布状
態を示すグラフであり、該グラフでアンカーの荷
重の分担は特に自由長を過ぎて定着部の始まる付
近に集中していることが理解できる。 However, on the other hand, Figures 2 and 3 are graphs showing the load distribution of anchors with anchorage lengths of 5.9 m and 11 m, respectively. It can be seen that they are concentrated near the beginning of .
PC鋼材ａに与えた荷重をグラウト材ｂが負担
するということは、上述したようにグラウト材ｂ
に引張り荷重が作用し、クラツクｃが発生するこ
とになる。そしてその荷重は定着部の始まる付近
に集中しているため、定着部の始まる付近にてク
ラツクｃが多く発生し、またそのクラツクｃの幅
は大きく容易に水が通過してPC鋼材ａの錆付き
及び破断を招いていた。 As mentioned above, grout material b bears the load applied to PC steel material a.
A tensile load will be applied to this, and a crack will occur. Since the load is concentrated near the beginning of the anchoring part, many cracks c occur near the beginning of the anchoring part, and the width of the crack c is large and water easily passes through, causing rust on the PC steel material a. This caused sticking and breakage.
従来アンカーの信頼を増大させるために定着部
の長さを必要以上に長く取つていたが、定着部の
始まる付近にてPC鋼材ａが切断してしまつたの
では、定着部の長さを必要以上に取つたとしても
何ら意味を成さなかつた。 Conventionally, in order to increase the reliability of the anchor, the length of the anchoring part was set longer than necessary, but if the PC steel material a broke near the beginning of the anchoring part, the length of the anchoring part should be made longer than necessary. Even if I took it further than that, it wouldn't make any sense.
問題点を解決するための手段
この発明にかかるプレストレストグランドアン
カー工法は、削孔内にPC鋼材を挿入し、まず最
奥部にグラウト材を注入して硬化せしめ、PC鋼
材を固定したのち緊張してプレストレスを与え、
次に再びグラウト材を注入して硬化した後緊張
し、プレストレスを与えるようにし、定着部を複
数段階に分割して形成し、各段階にて全荷重のう
ちの一部を分担させ、定着部の一部に荷重が集中
することによる大きなクラツクの発生を防止する
ようにして上記の問題点を解消するものである。Means for Solving the Problems The prestressed ground anchor construction method according to the present invention involves inserting a prestressed steel material into a drilled hole, first injecting grout into the deepest part and hardening it, fixing the prestressed steel material, and then applying tension. to give prestress,
Next, the grout material is injected again and after it hardens, it is tensioned and prestressed, and the anchoring part is formed by dividing it into multiple stages, each stage sharing a part of the total load, and then The above-mentioned problem is solved by preventing the occurrence of large cracks due to concentration of load on some parts.
実施例
以下図に示す一実施例に基づきこの発明を施工
順に沿つて説明する。Embodiment The present invention will be described below in accordance with the construction order based on an embodiment shown in the drawings.
＜１＞ 削孔の形成 地山に削孔１を形成する。<1> Forming the hole Drill hole 1 is formed in the ground.
＜２＞ PC鋼材の挿入
削孔１内にPC鋼材２を挿入する。PC鋼材２
の地表に近い部分はシース３内に挿通されてお
り、シース３内にはグリース４等が充填されて
いる。PC鋼材２のシース３内に挿通された部
分は自由長部Ａとして使用され、シース３から
突出した部分は定着部Ｂとして使用される。<2> Inserting the PC steel material Insert the PC steel material 2 into the drilled hole 1. PC steel material 2
The part near the ground surface is inserted into a sheath 3, and the sheath 3 is filled with grease 4 or the like. The portion of the PC steel material 2 that is inserted into the sheath 3 is used as the free length portion A, and the portion that protrudes from the sheath 3 is used as the anchor portion B.
＜３＞ PC鋼材の固定
PC鋼材２の定着部Ｂを複数段階に分割して、
まず削孔１の最奥部B1にグラウト材５を注入
して硬化させ、PC鋼材２の最奥端部を削孔１
内に固定する。<3> Fixing the PC steel material Divide the fixing part B of the PC steel material 2 into multiple stages,
First, the grout material 5 is injected into the innermost part B1 of the drilled hole 1 and hardened, and the innermost part of the PC steel material 2 is inserted into the innermost part B1 of the drilled hole 1.
Fixed inside.
＜４＞ プレストレス導入
PC鋼材２に最終的に与える全荷重の一部に
よつてPC鋼材２を緊張してプレストレスを導
入する。例えば最終的に210tonの荷重を与える
場合、まず70tonによつてPC鋼材２を緊張す
る。従つてグラウト材５には70tonの荷重しか
かからず、大きなクラツクは発生しない。<4> Introducing prestress Prestress is introduced by tensing the PC steel 2 by a portion of the total load finally applied to the PC steel 2. For example, when applying a final load of 210 tons, the PC steel material 2 is first tensed by 70 tons. Therefore, only a load of 70 tons is applied to the grout material 5, and no large cracks occur.
＜５＞ グラウト材の注入
定着部Ｂの第二段階B2にグラウト材５を注
入して硬化させる。グラウト材５が硬化したと
き、既に70tonにて緊張しているためPC鋼材２
には70tonのプレストレスが与えられ、しかも
第二段階B2のグラウト材５には引張り力は働
いていないためクラツクは全く発生していな
い。<5> Injection of grout material The grout material 5 is injected into the second stage B2 of the fixing section B and hardened. When the grout material 5 hardens, it is already under tension at 70 tons, so the PC steel material 2
A prestress of 70 tons was applied to the grout material 5 in the second stage B2 , and since no tensile force was acting on the grout material 5, no cracks were generated at all.
＜６＞ プレストレスの導入
第二段階B2のグラウト材５が硬化後全荷重
の一部をプレストレスとして導入する。例えば
上記につづいて70tonの荷重を加算してプレス
トレスとして導入すれば合計140tonのプレスト
レスがPC鋼材２に与えられることになる。<6> Introduction of prestress After the grout material 5 in the second stage B2 hardens, a part of the total load is introduced as prestress. For example, if a load of 70 tons is added and introduced as prestress following the above, a total of 140 tons of prestress will be applied to the PC steel material 2.
しかも第二段階B2のグラウト材５には70ton
の引張り荷重しか作用しないため、該グラウト
材５に生ずるクラツクは極めて小さいものとな
る。 In addition, grout material 5 in the second stage B2 weighs 70 tons.
Since only a tensile load of 1 is applied, the cracks that occur in the grout material 5 are extremely small.
＜７＞ グラウト材の注入及びプレストレスの導
入
既述したようにグラウト材５の注入及びプレ
ストレスの導入を段階ごとに繰り返して所要量
のプレストレスをPC鋼材２に与える。実施例
では第三段階B3にて再び70tonの荷重を加算す
ることによつてPC鋼材２を緊張して合計
210tonのプレストレスを与えた。<7> Injection of grout material and introduction of prestress As described above, the injection of grout 5 and introduction of prestress are repeated step by step to apply the required amount of prestress to the PC steel material 2. In the example, in the third stage B3 , a load of 70 tons is added again to tension the PC steel material 2 and the total
A prestress of 210 tons was applied.
＜８＞ グラウト材の注入
PC鋼材２に所要なプレストレスを与えた後、
最終段階B4のグラウト材５を注入して硬化さ
せる。従つて最終段階B4のグラウト材５には
全く引張り荷重が作用しておらず、荷重はそれ
以前の各段階にて分散して負担することにな
る。<8> Injection of grout material After applying the required prestress to the PC steel material 2,
The grout material 5 of the final stage B4 is injected and hardened. Therefore, no tensile load is applied to the grout material 5 in the final stage B4 , and the load is distributed and borne in each of the previous stages.
PC鋼材２に、予め与えたプレストレス以上
の荷重が作用した場合グラウト材５に引張り荷
重として作用する。既述したようにこの荷重は
定着部Ｂの始まり部分に集中するが、この発明
にかかる定着方法によつて定着したアンカーに
おいては定着部Ｂの始まり部分は最終段階B4
のグラウト材５に相当する。最終段階B4のグ
ラウト材５には全く引張り荷重が作用していな
いため、この時点で初めてグラウト材５に引張
り荷重が作用することになる。この荷重はPC
鋼材２に与えたプレストレス以上の荷重であつ
て余り大きな荷重とはならず、引張り荷重によ
つて生じるクラツクも大きなものにはならず、
水がクラツク内を通り過ぎることがない。 When a load greater than the prestress applied in advance acts on the PC steel material 2, it acts on the grout material 5 as a tensile load. As mentioned above, this load is concentrated at the starting part of the anchoring part B, but in the anchor fixed by the fixing method according to the present invention, the starting part of the anchoring part B is concentrated at the final stage B 4
This corresponds to the grout material 5 of . Since no tensile load is acting on the grout material 5 at the final stage B4 , a tensile load is applied to the grout material 5 for the first time at this point. This load is PC
The load is greater than the prestress applied to the steel material 2 and is not a very large load, and the cracks caused by the tensile load will not be large.
Water does not pass through the crack.
発明の効果
この発明にかかるプレストレストグランドアン
カー定着方法は以上のような構成を有し、定着部
を複数段階に分割して形成し、各段階にて全荷重
のうちの一部を分担するため荷重が一ケ所に集中
してグラウト材に大きなクラツクが発生するよう
なことがなく、クラツク内を水が通過せずPC鋼
材の錆付き、破断を発生させることなく、信頼で
きるアンカーとして施工できる。Effects of the Invention The prestressed ground anchor fixing method according to the present invention has the above-described configuration, and the fixing section is formed by dividing into multiple stages, and each stage shares a part of the total load, so the load is reduced. It does not concentrate in one place and cause large cracks in the grout, and water does not pass through the cracks, preventing rust or breakage of the prestressed steel, allowing construction as a reliable anchor.
このアンカーは長期的にその耐力を必要とされ
る永久構造物のアンカーとして価値が高い。 This anchor is valuable as an anchor for permanent structures that require long-term strength.
第１図はグラウト材にクラツクの発生した状態
の縦断面図、第２図及び第３図はプレストレスト
アンカーの荷重分布状態を示すグラフ、第４図は
シースに挿通したPC鋼材の一部縦断面図、第５
図は第４図の−線断面図、第６図は第４図の
−線断面図、第７図〜第１０図は施工順序説
明図である。
１……削孔、２……PC鋼材、３……シース、
４……グリース、５……グラウト材、Ａ……自由
長部、Ｂ……定着部。
Figure 1 is a longitudinal cross-sectional view of a state where cracks have occurred in the grout material, Figures 2 and 3 are graphs showing the load distribution state of the prestressed anchor, and Figure 4 is a partial longitudinal cross-section of the prestressed steel material inserted into the sheath. Figure, 5th
The figure is a sectional view taken along the - line in FIG. 4, FIG. 6 is a sectional view taken along the - line in FIG. 4, and FIGS. 7 to 10 are construction order explanatory views. 1...Drilling, 2...PC steel material, 3...Sheath,
4... Grease, 5... Grout material, A... Free length part, B... Fixing part.
Claims (1)
ラウト材を注入して硬化せしめ、PC鋼材を固定
した後緊張してプレストレスを与え、次に再びグ
ラウト材を注入して硬化した後緊張してプレスト
レスを与えるようにし、定着部を複数段階に分割
して形成し、各段階にて全荷重のうちの一部を分
担するようにしたことを特徴とするプレストレス
トグランドアンカー定着方法。1. Insert the prestressing steel material into the drilled hole, first inject grout into the deepest part and let it harden. After fixing the prestressing steel material, apply tension and prestress, then inject grout again and harden it. A prestressed ground anchor anchoring method characterized in that prestress is applied by post-tensioning, the anchoring part is divided into multiple stages, and a part of the total load is shared in each stage. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21759384A JPS6195124A (en) | 1984-10-17 | 1984-10-17 | Fixation of grand anchor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21759384A JPS6195124A (en) | 1984-10-17 | 1984-10-17 | Fixation of grand anchor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6195124A JPS6195124A (en) | 1986-05-13 |
| JPH0137533B2 true JPH0137533B2 (en) | 1989-08-08 |
Family
ID=16706723
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21759384A Granted JPS6195124A (en) | 1984-10-17 | 1984-10-17 | Fixation of grand anchor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6195124A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2501780B2 (en) * | 1991-05-22 | 1996-05-29 | 建設基礎エンジニアリング株式会社 | Anchor |
| JPH0733664B2 (en) * | 1991-06-10 | 1995-04-12 | 建設基礎エンジニアリング株式会社 | anchor |
| JP6903288B2 (en) * | 2017-03-01 | 2021-07-14 | 一般財団法人ダム技術センター | How to reinforce the ground, etc. |
-
1984
- 1984-10-17 JP JP21759384A patent/JPS6195124A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6195124A (en) | 1986-05-13 |
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