The Effect of Base Projecting Walls on the Bearing Capacity and Settlement of Shallow Foundations on Soft Ground

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** ༊⡍ݡ⦺Ʊ ☁༊Ŗ⦺ŝ ᕾᔍ ([email protected])

Received March 26 2013, Revised May 23 2013, Accepted May 28 2013

Copyright ⵑ 2013 by the Korean Society of Civil Engineers

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0)

ǣǣȀȀǤǤȀͳͲǤͳʹ͸ͷʹȀǤʹͲͳ͵Ǥ͵͵ǤͶǤͳͷʹ͵ ǤǤǤ

ⶾ′ᦊ㍚≻ⴂ#ⴲⱧ㬚#⮮⬻⽾⇖♿#⭓⳾Ꮾ㋆ⴖ#⽾ᙲᷣ#⽛ᢾ#㱦ኺ

ହஂজȵࢮ਎ผ

Lim Jongseok*, Park Seunghoon**

The Effect of Base Projecting Walls on the Bearing Capacity and Settlement of Shallow Foundations on Soft Ground

ABSTRACT

It is necessary to develop the simple and efficient technique that ease entry of man and equipment and take the role of foundations of temporary or small structures on the soft ground. This study intends to verify the effects on the increase of bearing capacity of base projecting walls under shallow foundations and to investigate the variance of the bearing capacity of the foundations according to the interval and length of the walls. For this, model soft ground in the chamber equipped with loading apparatus is made and the loading tests on the model foundations with base projecting walls of various intervals and lengths using the apparatus are performed with measuring the loads and settlements. The results show that the base projecting walls under shallow foundations on soft ground are effective on the increase of bearing capacity and the more the number and length of the walls the larger the effects. And, when the ratio of interval to length of the walls is 1, i.e. the shape forming the base of the foundation and the walls is square, the bearing capacity is increased by 25% and the effect is optimum.

Key words : Base projecting wall, Soft ground, Shallow foundation, Bearing capacity, Settlement, Model Test

Ⅹಾ

ᩑ᧞ḡၹᨱᱢᬊ⦹ᩍᯙಆၰᰆእ᮹ḥ᯦ᮥᬊᯕ⦹í⧉ᮡྜྷುӹᦥaa᜽ᖅᯕӹᗭ⩶Ǎ᳑ྜྷ᮹ʑⅩಽᕽ᮹ᩎ⧁ࠥa܆⦽e⠙⦹Ł⬉ᮉᱢ ᯙŖჶ᮹}ၽᯕ⦥᫵⦽ᝅᱶᯕ݅. ᅙᩑǍᨱᕽ۵᧶ᮡʑⅩᨱᖅ⊹ࡹ۵ᱡ໕࠭⇽ᄞ᮹ḡԕಆ᷾ݡ⬉ŝෝ⪶ᯙ⦹ŁeĊŝʙᯕᨱ঑௝ᩑ᧞ḡ ၹᔢʑⅩ᮹ḡԕಆᯕᨕਜíݍ௝ḡ۵aෝ᦭ᦥᅕŁᯱ⦹ᩡ݅. ᯕෝ᭥⦹ᩍᰍ⦹ᰆ⊹aᖅ⊹ࡽ☁᳑ᨱᩑ᧞ḡၹᮥ᳑ᖒ⦹Ł݅᧲⦽eĊŝʙ ᯕ᮹ᱡ໕࠭⇽ᄞᮥaḥ༉⩶ʑⅩᨱݡ⧕ᰍ⦹᜽⨹ᮥᝅ᜽⦹ᩍḡḡಆŝ⋉⦹పᮥ⊂ᱶ⦹ᩡ݅. əđŝᩑ᧞ḡၹᨱᕽ᧶ᮡʑⅩᨱᱡ໕࠭⇽ᄞᮥ

ᰆ⊹⦹໕ḡԕಆ᷾ݡ⬉ŝෝ᨜ᮥᙹᯩᮝ໑࠭⇽ᄞ᮹ʙᯕaʙᙹಾ, }ᙹa᷾a⧁ᙹಾᱥၹᱢᮝಽḡԕಆᮡ᷾a⦹۵᧲ᔢᮥᅕᩡ݅. ੱ⦽

ᱡ໕࠭⇽ᄞ᮹ʙᯕݡ⡎እa1ᯝভᷪ, ࠭⇽ᄞŝʑⅩᱡ໕ᯕᯕ൉۵⩶ᔢᯕᱶᔍb⩶ᯝভ↽ᱢ᮹⬉ŝෝᅕᯕ໑ᯕĞᬑḡԕಆᮡ᧞25% ᷾ ݡࡽ݅.

áᔪᨕ ᱡ໕࠭⇽ᄞ, ᩑ᧞ḡၹ, ᧶ᮡʑⅩ, ḡḡಆ, ⋉⦹ప, ḡԕಆ, ༉⩶᜽⨹

1. ᕽು

⩥ᰍb᳦ÕᖅŖᔍa݅᧲⦽᳑Õ᮹ḡၹᨱᕽᯕ൉ᨕḡŁᯩ݅. ᯕ్⦽ḡၹॅᵲᨱ۵ᦵၹŝzᯕݡ⩶Ǎ᳑ྜྷ᮹ʑⅩಽᕽࠥᗱᔪᨧ۵

čŁ⦽ḡၹᯕᯩ۵ၹ໕ᨱ⧕ᦩᱱ☁ḡၹ, ᵡᖅๅพḡၹ॒ŝzᯕᯙಆᯕӹᰆእ᮹ḥ᯦᳑₉ᨕಅᬕḡၹॅࠥᯩ݅. ᯕĞᬑ᧲ḩ☁ಽ

ݓъėॡ

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(a) Usual Foundation

(b) Foundation with Base Projecting Walls Fig. 1. Shape of Base Projecting Walls

(a) Front View (b) Side View

(c) Complete View of the Test (d) Loading and Measuring

Fig. 2. Model Test (Unit : mm) ᅖ☁⦹Ñӹݡӹྕ฾, v❱a॒ࠥᮥᖅ⊹⦹۵ႊჶᮥŁಅ⧁ᙹ

ᯩᮝӹ(ᯕᬊʙ, 2003) ᜽eŝእᬊ໕ᨱᕽእ⬉ᮉᱢᯙ⊂໕ᯕᯩ݅.

↽ɝᨱ۵vᰍๅ✙(ʡ᳦ʙ॒, 2012)ӹᅖ⧊ᗭᰍๅ✙(ᯕᖒᬑ॒, 2007)ෝᯕᬊ⦹۵ႊჶᯕᱽᦩࡹŁᯩᮝӹᦥḢձญᝅᬊ⪵ࡹᨩ݅

Łᅕʑ۵ᨕಖ݅. ঑௝ᕽᯕ్⦽ᩑ᧞ḡၹᨱᱢᬊ⦹ᩍᯙಆၰ

ᰆእ᮹ḥ᯦ᮥᬊᯕ⦹í⧉ᮡྜྷುӹᦥaa᜽ᖅᯕӹᗭ⩶Ǎ᳑ྜྷ

᮹ʑⅩಽᕽ᮹ᩎ⧁ࠥa܆⦽e⠙⦹Ł⬉ᮉᱢᯙŖჶ᮹}ၽᯕ

⦥᫵⦽ ᝅᱶᯕ݅.

ᱡ໕࠭⇽ᄞᮡFig. 1ŝzᯕᯝၹᱢᯙ᧶ᮡʑⅩ᮹ᱡ໕ᨱᄞℕෝ

࠭⇽᜽⍽ʑⅩ⦹ᇡḡၹ᮹ᄡ⩶ᮥǍᗮ⧉ᮝಽ៉ḡḡಆᮥ᷾ݡ᜽

┅Ł⋉⦹పᮥqᗭ᜽┅۵⬉ŝෝ᨜Łᯱ⦹۵äᯕ݅. ᯕ۵ᩑ᧞ḡ

ၹᨱ ᦶ᯦⦹۵ ႊ᜾ᮝಽ៉ ᖅ⊹ᨱ ঑ෙ ᄥࠥ᮹ ᯲ᨦᯕ ⦥᫵⊹

ᦫᦥ e⠙⦹Ł ᝁᗮ⦹í ᱢᬊ⧁ ᙹ ᯩ݅.

ǭ᪅ᙽ॒(2002a, b)ᮡᙹ⊹⧕ᕾŝ༉⩶᜽⨹ᮥ☖⦹ᩍᩑ᧞ḡၹ

ႊ❭ᱽᨱᱢᬊࡽᱡ໕࠭⇽ᄞᮝಽᯙ⦽ᦶၡ⋉⦹ప qᗭ⬉ŝᨱ

ݡ⧕ ᩑǍ⦽ ၵ ᯩ݅. ᩑǍđŝᨱ ঑෕໕ ࠭⇽ᄞᯕ ʙᨕḩᙹಾ

ᦶၡ⋉⦹పᯕqᗭ⦹ᩡᮝ໑࠭⇽ᄞ᮹ʙᯕa∊ᇥ⯩ʙ݅໕ᦶၡ

⋉⦹పᨱ ၙ⊹۵ ʑⅩ⡎᮹ ᩢ⨆ᮡ Ⓧḡ ᦫ݅Ł ⦹ᩡ݅. ə్ӹ

ʑⅩ⡎ŝ࠭⇽ᄞʙᯕ᪡᮹šĥa⋉⦹పᨱၙ⊹۵ᩢ⨆ᮥǍℕᱢ ᮝಽ ၾ⯩ḡ۵ ༜⦹ᩡ݅.

ᅙᩑǍᨱᕽ۵᧶ᮡʑⅩᨱᖅ⊹ࡹ۵ᱡ໕࠭⇽ᄞ᮹⬉ŝෝ⪶ᯙ

⧕ᅕŁ࠭⇽ᄞ᮹eĊŝʙᯕᨱ঑௝ᩑ᧞ḡၹᔢʑⅩ᮹ḡԕಆᯕ

ᨕਜíݍ௝ḡ۵aෝ᦭ᦥᅕŁᯱ⦹ᩡ݅. ᯕෝ᭥⦹ᩍᰍ⦹ᰆ⊹a

ᖅ⊹ࡽ☁᳑ᨱᩑ᧞ḡၹᮥ᳑ᖒ⦹Ł݅᧲⦽eĊŝʙᯕ᮹ᱡ໕࠭

⇽ᄞᮥaḥ༉⩶ʑⅩᨱݡ⧕ᰍ⦹᜽⨹ᮥᝅ᜽⦹ᩍḡḡಆŝ⋉⦹

ప᮹ šĥෝ ⊂ᱶ⦹ᩡ݅.

2. ᝅԕ༉⩶᜽⨹

2.1 ਏ෠Թ૬

ᅙ᜽⨹ᨱᕽ۵3₉ᬱᩢ⨆ᮥ႑ᱽ⦹Ł2₉ᬱᮝಽᙹ⧪⦹ʑ᭥⦹

ᩍaಽᨱእ⧕ᖙಽaṈᮡ800mm × 250mm᮹☁᳑ෝᱽ᯲⦹ᩡ

݅. ༉⩶᜽⨹ᰆ⊹ෝ Fig. 2ᨱ ᅕᯕŁ ᯩ݅.

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Fig. 3. Base of the Loading Plate with Projecting Walls

Fig. 4. Particle - size Distribution Curve of the Soil in Test Ground Table 1. Properties of the Soil in Test Ground

Properties Value

Liquid Limit, LL (%) 70.4

Plastic Limit, PL (%) 34.2 Plasticity Index, PI (%) 36.2 Specific Gravity,

_Ƒ

2.62 Soil Classification MH

᜽⨹ᨱ ᔍᬊࡽ ᰍ⦹❱ᮡ ࢱ̹ 1mm᮹ vᰍಽ ᱽ᯲⦹ᩡᮝ໑

⡎ᯕ100mmᯕŁʙᯕ۵☁᳑᮹ᖙಽ᪡እ᜘⦹í⦹ᩡ݅. ᯕভ

ᰍ⦹᜽ ☁᳑᮹ ᄞŝ ʑⅩ᮹ ษₑᮥ ↽ᗭ⪵⦹ʑ ᭥⦹ᩍ ʑⅩ᮹

ʙᯕෝ☁᳑᮹ᖙಽᅕ݅᧞eṈí⦹ᩡ݅. ᱡ໕࠭⇽ᄞᮡvᰍෝ

ᬊᱲ⦹ᩍ ᇡ₊⦹ᩡᮝ໑ }ᙹ۵ 2, 3, 4, 5}᮹ 4aḡ ⩶┽ᯕŁ

b ⩶┽ษ݅ ʙᯕ 1, 2, 3, 4, 5cm᮹ 5aḡෝ ᱽ᯲⦹ᩡ݅ (Fig.

3 ₙ᳑).

2.2 ࡦ෴஺ࢱ

༉⩶ḡၹᮡᕽԉ⧕ᦩḡᩎᯙ༊⡍᜽᮹༊⡍ݡƱᯙɝᨱᕽ₥≉

⦽⧕ᖒᱱ☁ෝᔍᬊ⦹ᩡᮝ໑ᯕ⮺᮹᯦ࠥᇥ⡍łᖁၰྜྷᖒsᮡ

bbFig. 4᪡Table 1ᨱӹ┡ԕᨩ݅. ༉⩶ḡၹᮥ᳑ᖒ⧁ভᨱ۵

ๅჩእ᜘⦽⧉ᙹእ᮹⮺ᮥᗱᮝಽၹᵞ⦹ᩍ☁᳑ᨱքᨩ݅. ᧞

24᜽eĞŝ⬥ᰍ⦹᜽⨹ᮥᝅ᜽⦹ᩡᮝ໑ᯕভḡၹ᮹ʫᯕ᧞

10cm ᮹⮺ᨱݡ⧕ᄁᯙᱥ݉᜽⨹ᮥᝅ᜽⦹Ł⧉ᙹእෝ⊂ᱶ⦹ᩡ݅.

əđŝእ႑ᙹᱥ݉vࠥ Ɓ

_Ɠ

۵↽ᗭ34.1kN/m²ᨱᕽ↽ݡ40.9kN/m² ᮹ ჵ᭥ᨱ ᯩᨩᮝ໑ ݡᇡᇥᮡ 37.5kN/m² ԕ᫙ᯕŁ ⧉ᙹእ۵

48~49%ᩍᕽ ๅ ᜽⨹ᮡ ᮁᔍ⦽ ḡၹ᳑Õᨱᕽ ᯕ൉ᨕᲭ݅Ł ᅝ

ᙹᯩ݅. ⪶ᯙᮥ᭥⦹ᩍᯝᇡḡၹᨱݡ⦹ᩍ2~3ᯝĞŝ⬥ᄁᯙᱥ݉

᜽⨹ᮥᝅ᜽⦹Ł⧉ᙹእෝ⊂ᱶ⦹ᩡ݅. ᯕভᨱࠥእ႑ᙹᱥ݉vࠥ

᪡⧉ᙹእ۵ᦿᨱᕽ᮹ჵ᭥ԕᨱᯩᨩ݅. ঑௝ᕽᅙḡၹᮡ24᜽e

ᯕᱥᨱ ᦩᱶࡹᨕ ᯕ⬥ಽ۵ ᄥ݅ෙ ᄡ⪵a ᨧ۵ äᮝಽ ᅕᯙ݅.

2.3 ਏ෠ࢺ࣑

ᅙ᜽⨹ᨱᕽ۵ຝᱡ᳑ᖒࡽᩑ᧞ḡၹ᭥ᨱᰍ⦹❱ᮥᖅ⊹⦽݅.

ᯕ ভ ᱡ໕࠭⇽ᄞᮥ Ҿʭḡ ɝ᯦⦹ᩍ ᰍ⦹❱᮹ ᱡ໕ᮥ ḡၹŝ

ၡ₊᜽⍽ĥ⊂᜽ᩢᱱᮥzí⦽݅. ಽऽᖡᨱḡəෝᩑđ⦹Ł

⋉⦹ప ⊂ᱶᮥ ᭥⦽ LVDTෝ ᰍ⦹❱ᨱ ᖅ⊹⦽ ⬥ ᰍ⦹⦹໕ᕽ

ߑᯕ░ಽÑෝᯕᬊ⦹ᩍLVDT᪡ಽऽᖡಽ⊂ᱶࡽsᮥPCಽ⇽ಆ

⦽݅. ⊂ᱶࡽ sᮥ aḡŁ ⦹ᵲ-⋉⦹ప łᖁᮥ ᯲ᖒ⦽݅.

3. ᜽⨹đŝၰᇥᕾ

3.1 ୠ࡟ܕౢ࣠׊ଲଭઽේ

ᅙᩑǍᨱᕽ۵ຝᱡzᮡ}ᙹ᮹ᱡ໕࠭⇽ᄞᨱݡ⦹ᩍʙᯕa

ݍ௝ḩĞᬑ᮹ᄡ⪵ෝ᦭ᦥᅕᦹ݅. Fig. 5᮹(a), (b), (c), (d)ᨱ۵

bb ࠭⇽ᄞ 2}, 3}, 4}, 5}ᯙ Ğᬑ ʙᯕa ݍ௝ḱᨱ ঑ෙ

⦹ᵲ-⋉⦹పłᖁᯕӹ┡ӹᯩ݅. bəฝᨱ۵༉ࢱእƱෝ᭥⦹ᩍ

ᱡ໕࠭⇽ᄞᯕ ᨧ۵ ᅕ☖᮹ ᰍ⦹❱ᨱ ݡ⦽ đŝࠥ ӹ┡ԕᨩ݅.

əฝᨱᕽ᦭ᙹᯩ۵ၵ᪡zᯕzᮡᙹ᮹ᱡ໕࠭⇽ᄞᯙĞᬑ

ʙᯕaʙᨕḱᨱ ঑௝ zᮡ⋉⦹పᨱ ࠥݍ⦹ʑ ᭥⦽⦹ᵲᯕ ޵

⍅ḡ۵ᷪ, ḡԕಆᯕ޵⍅ḡ۵Ğ⨆ᮥᅕᯕŁᯩ݅. ᯕ్⦽Ğ⨆ᮥ

ᇥᕾ⦹ʑ᭥⧕ᕽ۵ᬱ⊺ᱢᮝಽɚ⦽ḡḡಆᮥaḡŁእƱ⧁⦥᫵

a ᯩ݅.

ᰍ⦹᜽⨹ᮝಽᇡ░ɚ⦽ḡḡಆᮥᔑᱶ⦹۵ႊჶᮡᯝၹᱢᮝಽ

⦹ᵲ - ⋉⦹ప᮹šĥᨱᕽᗭᖒᱢᯙłᖁᇡᇥᨱᕽ݅᜽ྕ⦽Ḣᖁᮝ ಽᯕ⧪ࡹ۵᜽ᱱ᮹⦹ᵲᮥɚ⦽ḡḡಆᮝಽđᱶ⦹۵ႊჶᯕᯩ݅.

ᯕၷᨱࠥ Ǝ - _Ƒ , _Ǝ -s, p-s łᖁჶəญŁᰍ⦹❱⡎᮹

10%, 25% ჵ᭥ᨱ⧕ݚ⦹۵⋉⦹పᮥɚ⦽ḡḡಆᮝಽᅕ۵ႊჶ(ᱶ

⩶᜾ ॒, 2002; ʡݡ⩥ ॒, 2004) ॒ᯕ ᯩ݅.

Fig. 5 ᨱᕽᅕ໕ɚ⦽ḡḡಆ᮹đᱶᯕ݅ᗭᧁๅ⦽Ğᬑaݡᇡ ᇥᯕ݅. ə౑ߑᅙᩑǍ᪡zᮡĞᬑ۵ᔢݡᱢᯙḡḡಆ᮹᷾aෝ

᦭ᦥᅕ۵äᯕ༊ᱢᯕအಽǔᯕɚ⦽ḡḡಆᮥǍ⧁⦥᫵۵ᨧ݅Ł

ᅙ݅. ݡᝁᨱᗭᱶ᮹⋉⦹పᨱࠥݍ⦹ʑ᭥⦽⦹ᵲᮥaḡŁእƱ⦹

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(a) 2 Base Projecting Walls (b) 3 Base Projecting Walls

(c) 4 Base Projecting Walls (d) 5 Base Projecting Walls

Fig. 5. Influence of the Length of Base Projecting Walls

Fig. 6. Variation of Bearing Capacity Ratio by the Length of Base Projecting Walls

ʑಽ⦹ᩡ݅. ᯕᨱ঑௝ᅙᩑǍᨱᕽ۵⧎ᅖᱱᮥչᨕ⦹ᵲ᮹₉ᯕa

૽ಘ⧕ḡ۵ᰍ⦹❱⡎᮹25%ᨱ⧕ݚ⦹۵25mm ⋉⦹᜽᮹݉᭥໕ ᱢݚ⦹ᵲᮥ₥┾⦹ᩍእƱ⦹ʑಽ⦹ᩡ݅. ᱥၹᱥ݉❭ƕᯙĞᬑ

ɚ⦽ḡḡಆᮡʑⅩ᮹⋉⦹పᯕʑⅩ⡎᮹4ⴇ10% ჵ᭥ᨱᕽၽᔾ⦹

Łǎᇡᱥ݉❭ƕӹš᯦ᱥ݉❭ƕ᮹Ğᬑɚ⦽ḡḡಆᮡ⋉⦹పᯕ

ʑⅩ⡎᮹15ⴇ25% ჵ᭥ᨱᕽၽᔾ⦽݅(Vesic, 1973)۵ᩑǍࠥ

ᯩᮝအಽ ᅙ ᩑǍ᮹ 25mm ʑᵡᮡ ᱢᱩ⦹݅Ł ᅕᯙ݅.

ᅙᩑǍᨱᕽ۵ੱ⦽, እƱෝ᭥⦹ᩍ25mm ⋉⦹᜽᮹݉᭥໕ᱢݚ

⦹ᵲᮥ ༉ࢱ ᱡ໕࠭⇽ᄞᯕᨧ۵ᅕ☖᮹ ᰍ⦹❱᮹ Ğᬑಽӹ٥ᨕ

ᱶȽ⪵⦹ᩡ݅. ᯕ᪡zᯕᱶȽ⪵⦽sᮥḡḡಆእ(Bearing Capacity Ratio) ௝ ⦹ʑಽ ⦽݅. ᷪ,

⤗⤗᝼ᶛ á

Þ❗᧋ጣⳳᰔ⛋ ┝ᇫ ✃㒯㉧⛋ ÏÒ ⶿㒯 ∳⚯ ሿ♛᧋❘ቐ 㒯⡨ß Þ┋ᓻ ✃㒯㉧⛋ ÏÒ ⶿㒯 ∳⚯ ሿ♛᧋❘ቐ 㒯⡨ß

ᯕᔢ᮹ʑᵡᮥᔍᬊ⦹ᩍzᮡᙹ᮹ᱡ໕࠭⇽ᄞᨱݡ⧕ʙᯕᨱ

঑ෙ ⬉ŝෝ Fig. 6ᨱ ᅕᯕŁ ᯩ݅. əฝᨱᕽ ᦭ ᙹ ᯩ۵ ၵ᪡

zᯕ࠭⇽ᄞ᮹ʙᯕaʙᨕḩᙹಾḡḡಆእa᷾a⦹۵äᮥ⪶ᯙ

⦹ᩡ݅.

(5)

(a) 1 cm Base Projecting Walls (b) 2 cm Base Projecting Walls (c) 3 cm Base Projecting Walls

(d) 4 cm Base Projecting Walls (e) 5 cm Base Projecting Walls

Fig. 7. Influence of the Number of Base Projecting Walls

Fig. 8. Variation of Bearing Capacity Ratio by the Number of Base Projecting Walls

Fig. 9. h and b

3.2 ୠ࡟ܕౢ࣠Թ৤ଭઽේ

݅ᮭᮝಽ۵zᮡʙᯕ᮹ᱡ໕࠭⇽ᄞᯕ}ᙹaݍ௝ḱᨱ঑௝

⦹ᵲ-⋉⦹᧲ᔢᮡᨕਜíᄡ⦹۵ḡෝ᦭ᦥᅕʑ᭥⦹ᩍFig. 7ŝ

zᯕzᮡʙᯕᄥಽ}ᙹᨱ঑ෙᄡ⪵ෝࠥ᜽⦹ᩡᮝ໑Fig. 8ᨱ۵

zᮡʙᯕ᮹ᱡ໕࠭⇽ᄞ}ᙹᨱ঑ෙḡḡಆእ᮹ᄡ⪵ෝӹ┡ԕᨩ

݅. əฝᨱᕽᅕ໕࠭⇽ᄞ᮹}ᙹa۹ᨕԁᙹಾḡḡಆእ۵᷾a⦹

۵ߑ 1cmᯝ ভෝ ᱽ᫙⦹Ł۵ ࠭⇽ᄞ᮹ }ᙹa 4}ᨱᕽ 5}ಽ

۹ᨕԁ ভᨱ۵ ḡḡಆእa qᗭ⦹۵ äᮥ ⪶ᯙ⧁ ᙹ ᯩᨩ݅.

3.3 ୠ࡟ܕౢ࣠ଭ׊ଲ૕ԩգଭઽේ

ᯕᔢ᮹đŝᨱᕽᅕ໕ᱡ໕࠭⇽ᄞ᮹ʙᯕaʙᨕḩᙹಾḡḡಆ

ᮡ⍅ḥ݅Łᅝᙹᯩᮝӹzᮡʙᯕᨱᕽ}ᙹaฯᦥḥ݅Łĥᗮ

⍅ḡḡ۵ᦫ۵݅۵äᮥ᦭ᙹᯩᨩ݅. ޵ᬒᯕFig. 6ᨱᕽᅕ໕

࠭⇽ᄞ}ᙹaฯᮥভʙᯕᨱ঑ෙ᷾aᖙ۵᪥อ⧕ḱᮥ᦭ᙹ

ᯩ݅. ঑௝ᕽᩍʑᕽFig. 9ŝzᯕ࠭⇽ᄞʙᯕh, eĊb௝⦹Ł

ʙᯕݡeĊእh/bෝᄡᙹಽ⦹ᩍḡḡಆእෝFig. 10᪡zᯕ

ࠥ᜽⧕ᅕᦹ݅.

(6)

Fig. 10. Bearing Capacity Ratio According to h/b

Fig. 10᮹ᱱᖁᮡ⢽᜽ࡽᱱॅ᮹ݡℕᱢᯙ⠪Ɂᖁᯕ݅. ᯕᖁᨱᕽ

᦭ᙹᯩॐᯕh/ba᧞1ᯕࡹ໕ᷪ, ᱡ໕࠭⇽ᄞ᮹ʙᯕ᪡eĊᯕ

እ᜘⧕ᲙᕽʑⅩ❱ŝᱡ໕࠭⇽ᄞᯕᯕ൉۵⩶ᔢᯕᱶᔍb⩶ᨱa ʭ᪡ḡ໕↽ᱢ᮹⬉ŝෝ᨜ᮥᙹᯩ݅Łᅝᙹᯩ݅. ᯕভḡḡಆእ ۵᧞1.25ಽᕽḡḡಆ᷾ݡ⬉ŝ۵᧞25%ᯕ݅. ᯕ۵⬉ŝᱢᯙ

ᱡ໕࠭⇽ᄞᮥ ᖅĥᨱ ࠥᬡᯕ ࢁ äᮝಽ ᅕᯙ݅.

4. đು

ᩑ᧞ḡၹᨱᕽ᧶ᮡʑⅩᨱᱡ໕࠭⇽ᄞᮥᰆ⊹⦹ᩍḡԕಆ᷾ݡ

⬉ŝෝ᨜۵ႊჶᮥ᦭ᦥᅕʑ᭥⦹ᩍᱡ໕࠭⇽ᄞ᮹}ᙹ᪡ʙᯕෝ

ݍญ⦽ʑⅩ❱ᮥᯕᬊ⦹ᩍᰍ⦹᜽⨹ᮥᝅ᜽⦹ᩍ⦹ᵲᨱ঑ෙ⋉⦹

పᮥ ⊂ᱶ⦹ᩡᮝ໑ ᜽⨹đŝ ᇥᕾᮥ ☖⧕ ݅ᮭŝ zᮡ đುᮥ

᨜ᮥ ᙹ ᯩᨩ݅.

(1) ᩑ᧞ḡၹᨱᕽ᧶ᮡʑⅩᨱᱡ໕࠭⇽ᄞᮥᰆ⊹⦹໕ḡԕಆ᷾ݡ

⬉ŝෝ ᨜ᮥ ᙹ ᯩ݅.

(2) ᱡ໕࠭⇽ᄞ᮹}ᙹazᮡĞᬑ࠭⇽ᄞ᮹ʙᯕaʙᙹಾḡԕ ಆᮡ ᷾a⦹۵ ᧲ᔢᮥ ᅕᯙ݅.

(3) ʙᯕazᮡᱡ໕࠭⇽ᄞ᮹Ğᬑ࠭⇽ᄞ᮹}ᙹa᷾a⧁ᙹಾ

ḡԕಆᮡ᷾a⦹۵᧲ᔢᮥᅕᯕ݅aʙᯕ1cmᯙĞᬑෝᱽ᫙

⦹Ł۵4}ᨱᕽ5}ಽ۹ᨕԁভ۵qᗭ⦹۵Ğ⨆ᮥᅕᩡ݅.

(4) ᱡ໕࠭⇽ᄞ᮹ ʙᯕ ݡ ⡎ እa 1ᯝ ভ ᷪ, ࠭⇽ᄞŝ ʑⅩ

ᱡ໕ᯕᯕ൉۵⩶ᔢᯕᱶᔍb⩶ᨱaʭᬭḩᙹಾ↽ᱢ᮹⬉ŝෝ

᨜ᮥᙹᯩᮝ໑ᯕভ᧞25%᮹ḡḡಆ᷾ݡ⬉ŝaᯩ݅.

qᔍ᮹ɡ

ᅙםྙᮡ2012⦺֥ࠥ༊⡍ݡ⦺ƱƱԕᩑǍእḡᬱᨱ᮹⦹ᩍ

ᩑǍࡹᨩᮭ.

References

Chung, H. S. and Kim, D. Y. (2002). “Characteristics of bearing capacity and settlement according to the difference of loading plate size.” Journal of Korean Geotechnical Society, Vol. 18, No.

4, pp. 179-188 (in Korean).

Kim, D. H. and Yamamoto, K. (2004). “Upper bound limit analysis of bearing capacity for surface foundations on sand overlying clay.” Journal of Korean Geotechnical Society, Vol. 20, No. 3, pp. 85-96 (in Korean).

Kim, J. G., Choi, G. Y. and Han, S. H. (2012). “Method for structural steel mat to secure trafficability on access road on soft ground.”

Proceedings of the Korean Society of Civil Engineers, pp.

1314-1317 (in Korean).

Kwon, O. S., Jang, I. S., Park, W. S. and Yum, K. D. (2002a).

“Consolidation settlement of the soft ground breakwater.” Journal of the Korean Society of Civil Engineers, Vol. 22, No. 1-B, pp.

57-66 (in Korean).

Kwon, O. S., Jang, I. S., Park, W. S. and Yum, K. D. (2002b).

“Applicability Evaluation of One Dimensional Consolidation Theory to the New Type Soft Ground Breakwater.” Journal of the Korean Society of Civil Engineers, Vol. 22, No. 6-B, pp. 833-842

(in Korean).

Lee, S. W., Hong, K. J., Cho, S. H. and Sim, Y. S. (2007). “Design and manufacturing of composite rigmat for temporary road in de- velopment of oil fields.” Proceedings of the Korean Society of Civil Engineers, pp. 166-169 (in Korean).

Lee, Y. G. (2003). “Technique of temporary road by steel plate for secure the drivability on weak ground.” Geotechnical Engineering, Korean Geotechnical Society, Vol. 19, No. 8, pp. 31-37 (in Korean).

Vesic, A. S. (1973). “Analysis of ultimate loads of shallow foundations.” Journal of the Soil Mechanics and Foundation Engineering Division, American Society of Civil Engineers, Vol.

99, No. SM1, pp. 45-73.

The Effect of Base Projecting Walls on the Bearing Capacity and Settlement of Shallow Foundations on Soft Ground

** ༊⡍ݡ⦺Ʊ ☁༊Ŗ⦺ŝ ᕾᔍ ([email protected])

Received March 26 2013, Revised May 23 2013, Accepted May 28 2013

Copyright ⵑ 2013 by the Korean Society of Civil Engineers

 ǣǣȀȀǤǤȀͳͲǤͳʹ͸ͷʹȀ ǤʹͲͳ͵Ǥ͵͵ǤͶǤͳͷʹ͵ Ǥ ǤǤ

ହஂজ ȵࢮ਎ผ

Lim Jongseok*, Park Seunghoon**

The Effect of Base Projecting Walls on the Bearing Capacity and Settlement of Shallow Foundations on Soft Ground

ABSTRACT

Key words : Base projecting wall, Soft ground, Shallow foundation, Bearing capacity, Settlement, Model Test

Ⅹಾ

ᰆ⊹⦹໕ḡԕಆ᷾ݡ⬉ŝෝ᨜ᮥᙹᯩᮝ໑࠭⇽ᄞ᮹ʙᯕaʙᙹಾ, }ᙹa᷾a⧁ᙹಾᱥၹᱢᮝಽḡԕಆᮡ᷾a⦹۵᧲ᔢᮥᅕᩡ݅. ੱ⦽

ᱡ໕࠭⇽ᄞ᮹ʙᯕݡ⡎እa1ᯝভᷪ, ࠭⇽ᄞŝʑⅩᱡ໕ᯕᯕ൉۵⩶ᔢᯕᱶᔍb⩶ᯝভ↽ᱢ᮹⬉ŝෝᅕᯕ໑ᯕĞᬑḡԕಆᮡ᧞25% ᷾ ݡࡽ݅.

áᔪᨕ ᱡ໕࠭⇽ᄞ, ᩑ᧞ḡၹ, ᧶ᮡʑⅩ, ḡḡಆ, ⋉⦹ప, ḡԕಆ, ༉⩶᜽⨹

1. ᕽು

⩥ᰍb᳦ÕᖅŖᔍa݅᧲⦽᳑Õ᮹ḡၹᨱᕽᯕ൉ᨕḡŁᯩ݅. ᯕ్⦽ḡၹॅᵲᨱ۵ᦵၹŝzᯕݡ⩶Ǎ᳑ྜྷ᮹ʑⅩಽᕽࠥᗱᔪᨧ۵

čŁ⦽ḡၹᯕᯩ۵ၹ໕ᨱ⧕ᦩᱱ☁ḡၹ, ᵡᖅๅพḡၹ॒ŝzᯕᯙಆᯕӹᰆእ᮹ḥ᯦᳑₉ᨕಅᬕḡၹॅࠥᯩ݅. ᯕĞᬑ᧲ḩ☁ಽ

  

(a) Usual Foundation

(b) Foundation with Base Projecting Walls Fig. 1. Shape of Base Projecting Walls

(a) Front View (b) Side View

(c) Complete View of the Test (d) Loading and Measuring

Fig. 2. Model Test (Unit : mm) ᅖ☁⦹Ñӹݡӹྕ฾, v❱a॒ࠥᮥᖅ⊹⦹۵ႊჶᮥŁಅ⧁ᙹ

ᯩᮝӹ(ᯕᬊʙ, 2003) ᜽eŝእᬊ໕ᨱᕽእ⬉ᮉᱢᯙ⊂໕ᯕᯩ݅.

↽ɝᨱ۵vᰍๅ✙(ʡ᳦ʙ॒, 2012)ӹᅖ⧊ᗭᰍๅ✙(ᯕᖒᬑ॒, 2007)ෝᯕᬊ⦹۵ႊჶᯕᱽᦩࡹŁᯩᮝӹᦥḢձญᝅᬊ⪵ࡹᨩ݅

Łᅕʑ۵ᨕಖ݅. ঑௝ᕽᯕ్⦽ᩑ᧞ḡၹᨱᱢᬊ⦹ᩍᯙಆၰ

ᰆእ᮹ḥ᯦ᮥᬊᯕ⦹í⧉ᮡྜྷುӹᦥaa᜽ᖅᯕӹᗭ⩶Ǎ᳑ྜྷ

᮹ʑⅩಽᕽ᮹ᩎ⧁ࠥa܆⦽e⠙⦹Ł⬉ᮉᱢᯙŖჶ᮹}ၽᯕ

⦥᫵⦽ ᝅᱶᯕ݅.

ᱡ໕࠭⇽ᄞᮡFig. 1ŝzᯕᯝၹᱢᯙ᧶ᮡʑⅩ᮹ᱡ໕ᨱᄞℕෝ

࠭⇽᜽⍽ʑⅩ⦹ᇡḡၹ᮹ᄡ⩶ᮥǍᗮ⧉ᮝಽ៉ḡḡಆᮥ᷾ݡ᜽

┅Ł⋉⦹పᮥqᗭ᜽┅۵⬉ŝෝ᨜Łᯱ⦹۵äᯕ݅. ᯕ۵ᩑ᧞ḡ

ၹᨱ ᦶ᯦⦹۵ ႊ᜾ᮝಽ៉ ᖅ⊹ᨱ ঑ෙ ᄥࠥ᮹ ᯲ᨦᯕ ⦥᫵⊹

ᦫᦥ e⠙⦹Ł ᝁᗮ⦹í ᱢᬊ⧁ ᙹ ᯩ݅.

ǭ᪅ᙽ॒(2002a, b)ᮡᙹ⊹⧕ᕾŝ༉⩶᜽⨹ᮥ☖⦹ᩍᩑ᧞ḡၹ

ႊ❭ᱽᨱᱢᬊࡽᱡ໕࠭⇽ᄞᮝಽᯙ⦽ᦶၡ⋉⦹ప qᗭ⬉ŝᨱ

ݡ⧕ ᩑǍ⦽ ၵ ᯩ݅. ᩑǍđŝᨱ ঑෕໕ ࠭⇽ᄞᯕ ʙᨕḩᙹಾ

ᦶၡ⋉⦹పᯕqᗭ⦹ᩡᮝ໑࠭⇽ᄞ᮹ʙᯕa∊ᇥ⯩ʙ݅໕ᦶၡ

⋉⦹పᨱ ၙ⊹۵ ʑⅩ⡎᮹ ᩢ⨆ᮡ Ⓧḡ ᦫ݅Ł ⦹ᩡ݅. ə్ӹ

ʑⅩ⡎ŝ࠭⇽ᄞʙᯕ᪡᮹šĥa⋉⦹పᨱၙ⊹۵ᩢ⨆ᮥǍℕᱢ ᮝಽ ၾ⯩ḡ۵ ༜⦹ᩡ݅.

ᅙᩑǍᨱᕽ۵᧶ᮡʑⅩᨱᖅ⊹ࡹ۵ᱡ໕࠭⇽ᄞ᮹⬉ŝෝ⪶ᯙ

⧕ᅕŁ࠭⇽ᄞ᮹eĊŝʙᯕᨱ঑௝ᩑ᧞ḡၹᔢʑⅩ᮹ḡԕಆᯕ

ᨕਜíݍ௝ḡ۵aෝ᦭ᦥᅕŁᯱ⦹ᩡ݅. ᯕෝ᭥⦹ᩍᰍ⦹ᰆ⊹a

ᖅ⊹ࡽ☁᳑ᨱᩑ᧞ḡၹᮥ᳑ᖒ⦹Ł݅᧲⦽eĊŝʙᯕ᮹ᱡ໕࠭

⇽ᄞᮥaḥ༉⩶ʑⅩᨱݡ⧕ᰍ⦹᜽⨹ᮥᝅ᜽⦹ᩍḡḡಆŝ⋉⦹

ప᮹ šĥෝ ⊂ᱶ⦹ᩡ݅.

2. ᝅԕ༉⩶᜽⨹

2.1 ਏ෠Թ૬

ᅙ᜽⨹ᨱᕽ۵3₉ᬱᩢ⨆ᮥ႑ᱽ⦹Ł2₉ᬱᮝಽᙹ⧪⦹ʑ᭥⦹

ᩍaಽᨱእ⧕ᖙಽaṈᮡ800mm × 250mm᮹☁᳑ෝᱽ᯲⦹ᩡ

݅. ༉⩶᜽⨹ᰆ⊹ෝ Fig. 2ᨱ ᅕᯕŁ ᯩ݅.

Fig. 3. Base of the Loading Plate with Projecting Walls

Fig. 4. Particle - size Distribution Curve of the Soil in Test Ground Table 1. Properties of the Soil in Test Ground

Properties Value

Liquid Limit, LL (%) 70.4

Plastic Limit, PL (%) 34.2 Plasticity Index, PI (%) 36.2 Specific Gravity,

2.62

Soil Classification MH

᜽⨹ᨱ ᔍᬊࡽ ᰍ⦹❱ᮡ ࢱ̹ 1mm᮹ vᰍಽ ᱽ᯲⦹ᩡᮝ໑

⡎ᯕ100mmᯕŁʙᯕ۵☁᳑᮹ᖙಽ᪡እ᜘⦹í⦹ᩡ݅. ᯕভ

ᰍ⦹᜽ ☁᳑᮹ ᄞŝ ʑⅩ᮹ ษₑᮥ ↽ᗭ⪵⦹ʑ ᭥⦹ᩍ ʑⅩ᮹

ʙᯕෝ☁᳑᮹ᖙಽᅕ݅᧞eṈí⦹ᩡ݅. ᱡ໕࠭⇽ᄞᮡvᰍෝ

ᬊᱲ⦹ᩍ ᇡ₊⦹ᩡᮝ໑ }ᙹ۵ 2, 3, 4, 5}᮹ 4aḡ ⩶┽ᯕŁ

b ⩶┽ษ݅ ʙᯕ 1, 2, 3, 4, 5cm᮹ 5aḡෝ ᱽ᯲⦹ᩡ݅ (Fig.

3 ₙ᳑).

2.2 ࡦ෴஺ࢱ

༉⩶ḡၹᮡᕽԉ⧕ᦩḡᩎᯙ༊⡍᜽᮹༊⡍ݡƱᯙɝᨱᕽ₥≉

⦽⧕ᖒᱱ☁ෝᔍᬊ⦹ᩡᮝ໑ᯕ⮺᮹᯦ࠥᇥ⡍łᖁၰྜྷᖒsᮡ

bbFig. 4᪡Table 1ᨱӹ┡ԕᨩ݅. ༉⩶ḡၹᮥ᳑ᖒ⧁ভᨱ۵

ๅჩእ᜘⦽⧉ᙹእ᮹⮺ᮥᗱᮝಽၹᵞ⦹ᩍ☁᳑ᨱքᨩ݅. ᧞

24᜽eĞŝ⬥ᰍ⦹᜽⨹ᮥᝅ᜽⦹ᩡᮝ໑ᯕভḡၹ᮹ʫᯕ᧞

10cm ᮹⮺ᨱݡ⧕ᄁᯙᱥ݉᜽⨹ᮥᝅ᜽⦹Ł⧉ᙹእෝ⊂ᱶ⦹ᩡ݅.

əđŝእ႑ᙹᱥ݉vࠥ Ɓ

۵↽ᗭ34.1kN/m²ᨱᕽ↽ݡ40.9kN/m² ᮹ ჵ᭥ᨱ ᯩᨩᮝ໑ ݡᇡᇥᮡ 37.5kN/m² ԕ᫙ᯕŁ ⧉ᙹእ۵

48~49%ᩍᕽ ๅ ᜽⨹ᮡ ᮁᔍ⦽ ḡၹ᳑Õᨱᕽ ᯕ൉ᨕᲭ݅Ł ᅝ

ᙹᯩ݅. ⪶ᯙᮥ᭥⦹ᩍᯝᇡḡၹᨱݡ⦹ᩍ2~3ᯝĞŝ⬥ᄁᯙᱥ݉

᜽⨹ᮥᝅ᜽⦹Ł⧉ᙹእෝ⊂ᱶ⦹ᩡ݅. ᯕভᨱࠥእ႑ᙹᱥ݉vࠥ

᪡⧉ᙹእ۵ᦿᨱᕽ᮹ჵ᭥ԕᨱᯩᨩ݅. ঑௝ᕽᅙḡၹᮡ24᜽e

ᯕᱥᨱ ᦩᱶࡹᨕ ᯕ⬥ಽ۵ ᄥ݅ෙ ᄡ⪵a ᨧ۵ äᮝಽ ᅕᯙ݅.

2.3 ਏ෠ࢺ࣑

ǣǣȀȀǤǤȀͳͲǤͳʹ͸ͷʹȀǤʹͲͳ͵Ǥ͵͵ǤͶǤͳͷʹ͵ ǤǤǤ

ହஂজȵࢮ਎ผ

áᔪᨕ ᱡ໕࠭⇽ᄞ, ᩑ᧞ḡၹ, ᧶ᮡʑⅩ, ḡḡಆ, ⋉⦹ప, ḡԕಆ, ༉⩶᜽⨹

ᯕၷᨱࠥ Ǝ - _Ƒ , _Ǝ -s, p-s łᖁჶəญŁᰍ⦹❱⡎᮹

Þ❗᧋ጣⳳᰔ⛋ ┝ᇫ ✃㒯㉧⛋ ÏÒ ⶿㒯 ∳⚯ ሿ♛᧋❘ቐ 㒯⡨ß Þ┋ᓻ ✃㒯㉧⛋ ÏÒ ⶿㒯 ∳⚯ ሿ♛᧋❘ቐ 㒯⡨ß