JP3479802B2 - Improvement method of sandy ground by compacted sand pile - Google Patents
Improvement method of sandy ground by compacted sand pileInfo
- Publication number
- JP3479802B2 JP3479802B2 JP19348999A JP19348999A JP3479802B2 JP 3479802 B2 JP3479802 B2 JP 3479802B2 JP 19348999 A JP19348999 A JP 19348999A JP 19348999 A JP19348999 A JP 19348999A JP 3479802 B2 JP3479802 B2 JP 3479802B2
- Authority
- JP
- Japan
- Prior art keywords
- ground
- improvement
- sand pile
- sandy ground
- pile
- 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 - Lifetime
Links
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Description
【０００１】[0001]
【発明が属する技術分野】本発明は、締固め砂杭による
砂質地盤の改良工法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving sandy ground using compacted sand piles.
【０００２】[0002]
【従来の技術】締固め砂杭を造成して砂質地盤を改良す
る場合は、改良後の地盤の間隙比を予測し、これに基づ
いて、所要の改良率（砂杭と改良地盤の面積比）を算出
し、砂杭径と砂杭ピッチを定めて、砂杭の造成を行うの
が通例であるが、従来、前述の間隙比の予側の精度を向
上させ、もつて、改良率を低下させて、施工の経済性を
高めることが望まれていた。2. Description of the Related Art When compacted sand piles are constructed to improve sandy ground, the void ratio of the ground after the improvement is predicted, and the required improvement rate (area of sand pile and improved ground is estimated based on this). It is customary to calculate the ratio) and determine the sand pile diameter and sand pile pitch to create the sand pile, but conventionally, the accuracy of the above-mentioned gap ratio on the preliminary side was improved, and the improvement rate It has been desired to reduce the construction cost and improve the economical efficiency of construction.
【０００３】[0003]
【発明が解決しようとする課題】本発明が解決しようと
する課題（本発明の目的）は、前記要望に応えて経済的
な締固め砂杭による砂質地盤の改良工法を提供すること
にある。SUMMARY OF THE INVENTION The problem to be solved by the present invention (object of the present invention) is to provide an economical improvement method for sandy ground by compacted sand piles in response to the above demand. .
【０００４】[0004]
【課題を解決するための手段】前記課題を解決するため
に、本発明の締固め砂杭による砂質地盤の改良工法（以
下、本発明の工法という）では、締固め砂杭を施工して
砂質地盤を改良する際に、改良率を前記式（１）に基づ
いて定めるようにしている。In order to solve the above problems, in the method for improving the sandy ground by the compacted sand pile of the present invention (hereinafter referred to as the method of the present invention), the compacted sand pile is constructed. When the sandy ground is improved, the improvement rate is determined based on the equation (1).
【０００５】本発明の工法を実施する場合、前記式
（１）のαは前記式（２）から逆算して定めることがで
きるが、別途、過去のデータ等に基づき定めても構わな
い。When the method of the present invention is carried out, α in the equation (1) can be determined by back-calculating from the equation (2), but it may be determined separately based on past data and the like.
【０００６】なお、本発明の工法では、一般に、砂質地
盤では細粒分含有率が高いほど、砂杭の造成による地盤
の締固め効果が小さく、したがって、このとき砂杭の造
成に伴う杭間地盤の体積圧縮が相対的に少なくなって、
地盤の盛り上がり現象が生じることがある、という知見
に基づき、砂杭造成後の地盤の体積変化を考慮して、有
効締固め係数を導入し、また、杭間地盤の締固め度が杭
間位置で異なることから、杭間位置換算係数を導入し
て、砂杭造成後の地盤の間隙比を算出するようにしてお
り、これによって、実情に即して合理的で経済的な砂杭
造成による砂質地盤の改良を行うことができる。In the method of the present invention, generally, the higher the content of fine grains in sandy ground, the smaller the effect of compacting the ground due to the formation of sand piles. The volume compression of the ground is relatively small,
Based on the knowledge that ground swelling phenomenon may occur, an effective compaction coefficient was introduced in consideration of the volume change of the ground after sand pile construction, and the degree of compaction of inter-pile ground Therefore, the position conversion factor between piles is introduced to calculate the porosity ratio of the ground after the sand pile is constructed, which enables the rational and economical sand pile construction according to the actual situation. The sandy ground can be improved.
【０００７】[0007]
【発明の実施の形態】本発明の方法で用いる前記式
（１），式（２）は、図１に図解されているとおりであ
り、これらの式におけるＲｃは、The above formulas (1) and (2) used in the method of the present invention are as illustrated in FIG. 1, and R c in these formulas is
【数３】
から求められ、これが、０に等しいときは改良効果がな
く、０より大きく１より小さいときは図示のとおり改良
後に体積の増加があり、１に等しいときは改良後も体積
変化がない。[Equation 3] When it is equal to 0, there is no improvement effect, when it is larger than 0 and smaller than 1, there is an increase in volume after improvement as shown in the figure, and when it is equal to 1, there is no volume change even after improvement.
【０００８】また、αは、図２に示すように、杭間の中
央位置では１であり、杭に近い位置では１より大きく、
過去の事例から式（２）により逆算した平均的数値は
１．５程度であるが、設計によっては、安全の見地から
従来通りに１としてもよい。As shown in FIG. 2, α is 1 at the central position between the piles and is larger than 1 at the position close to the piles.
The average value calculated back by the formula (2) from the past cases is about 1.5, but it may be 1 as usual from the viewpoint of safety depending on the design.
【０００９】なお、本発明の工法を実施する場合、原地
盤の土質調査で原地盤Ｎ値を求めるとともに、上部工の
条件等から改良地盤の目標Ｎ値を定め、原地盤Ｎ値から
原地盤の間隙比を、また、目標Ｎ値から改良地盤の間隙
比を、それぞれ求め、これら間隙比の数値を式（１）に
代入して、所要の改良率を算出し、この改良率になるよ
うに砂杭径と砂杭ピッチを定めて、砂杭造成を行うので
あるが、その具体的手法は従来公知であるので、これ以
上の説明は省略する。When carrying out the method of the present invention, the original ground N value is determined by soil investigation of the original ground, the target N value of the improved ground is determined from the conditions of the superstructure, and the original ground N value is used. , And the void ratio of the improved ground from the target N value. Substituting the numerical values of these void ratios into equation (1), the required improvement ratio is calculated, and this improvement ratio is obtained. The sand pile diameter is determined and the sand pile pitch is determined, and the sand pile is formed. However, since the specific method is conventionally known, further description will be omitted.
【図１】式（１）と式（２）の説明図であり、（イ）は
原地盤の状態を、（ロ）は改良地盤の状態を、それぞれ
示している。FIG. 1 is an explanatory diagram of equations (1) and (2), in which (a) shows the state of the original ground and (b) shows the state of the improved ground.
【図２】α（杭間位置換算係数）の説明図である。FIG. 2 is an explanatory diagram of α (inter-pile position conversion coefficient).
───────────────────────────────────────────────────── フロントページの続き (72)発明者 磯田 知広 東京都台東区台東１−２−１ 不動建設 株式会社内 (56)参考文献 特開 平10−183592（ＪＰ，Ａ) 特開 平10−237856（ＪＰ，Ａ) 特開 平６−65914（ＪＰ，Ａ) 特開 平５−132923（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Tomohiro Isoda 1-2-1 Taito, Taito-ku, Tokyo Immovable construction Within the corporation (56) References Japanese Patent Laid-Open No. 10-183592 (JP, A) Japanese Patent Laid-Open No. 10-237856 (JP, A) JP-A-6-65914 (JP, A) Japanese Patent Laid-Open No. 5-132923 (JP, A)
Claims (2)
る際に、改良地盤に体積変化があることを前提にし、改
良率を ｅ１＝ ｅ０−α・Ｒｃ（１＋ｅ０）・ａｓ ・・・・・・（１） ｅ１： 改良地盤の間隙比 ｅ０： 原地盤の間隙比 α ： 杭間位置換算係数（１以上の数） Ｒｃ： 有効締固め係数（細粒分含有率の関数） ａｓ： 改良率 に基づいて定めることを特徴とする締固め砂杭による砂
質地盤の改良工法。1. When the compacted sand pile is constructed to improve the sandy ground , the improvement rate is e 1 = e 0 −α · R c (1 + e 0) on the assumption that the improved ground has a volume change. ) · a s ······ (1) e 1: improved ground clearance ratio e 0: void ratio of the original ground alpha: pile between position conversion factor (a number of 1 or more) R c: the effective compaction coefficient ( Function of fine particle content) a s : Method for improving sandy ground by compacted sand piles characterized by being determined based on improvement rate.
はＯ） Ｄ ： 原地盤の層厚（ｍ） Ｒｃ： 有効締固め係数（細粒分含有率の関数） ａｓ： 改良率 から逆算して定める請求項１記載の締固め砂杭による砂
質地盤の改良工法。Wherein the alpha of the formula (1) in claim 1 H = (1-α · R c) · D · a s ······ (2) H: Sunakui average raised height of the surrounding ground S (lateral displacement is O) D: Layer thickness of the original ground (m) R c : Effective compaction coefficient (function of fine particle content rate) a s : Consolidation determined by back calculation from improvement rate Improvement method of sandy ground by solidified sand piles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19348999A JP3479802B2 (en) | 1999-06-04 | 1999-06-04 | Improvement method of sandy ground by compacted sand pile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19348999A JP3479802B2 (en) | 1999-06-04 | 1999-06-04 | Improvement method of sandy ground by compacted sand pile |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000345553A JP2000345553A (en) | 2000-12-12 |
| JP3479802B2 true JP3479802B2 (en) | 2003-12-15 |
Family
ID=16308898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19348999A Expired - Lifetime JP3479802B2 (en) | 1999-06-04 | 1999-06-04 | Improvement method of sandy ground by compacted sand pile |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3479802B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3973637B2 (en) * | 2004-03-10 | 2007-09-12 | 井上工業株式会社 | Ground improvement method |
| KR101904229B1 (en) * | 2016-08-09 | 2018-10-04 | 이엑스티 주식회사 | Replacement method of ground for raising seismic classification |
-
1999
- 1999-06-04 JP JP19348999A patent/JP3479802B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000345553A (en) | 2000-12-12 |
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