경량포장시스템용최적하부기초시스템결정 CONTENTS < pile 와토목합성섬유의결합 > vembankments reinforced by piles and geosynthetics Numerical and experimental studies deal

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경량포장시스템용최적하부기초시스템결정 CONTENTS < pile 와토목합성섬유의결합 > vembankments reinforced by piles and geosynthetics Numerical and experimental studies dealing with the transfer of load on the soil embankment (By B.

Embankments reinforced by piles and geosynthetics Numerical and experimental studies dealing with the transfer of load on the soil embankment Ⅲ. 연안역과제에서의활용 2010. 01. 11 공주대학교 Ⅰ.

1 경량포장시스템용최적하부기초시스템결정 CONTENTS < pile 와토목합성섬유의결합 > vembankments reinforced by piles and geosynthetics Numerical and experimental studies dealing with the transfer of load on the soil embankment (By B. Le Hello, P.Villard-2009) v 지오그리드와말뚝에의한연약지반보강효과 (By 이명원, 허열, 신은철 -2000) I. 지오그리드와말뚝에의한연약지반보강효과 II. Embankments reinforced by piles and geosynthetics Numerical and experimental studies dealing with the transfer of load on the soil embankment Ⅲ. 연안역과제에서의활용 공주대학교 Ⅰ. 논문의배경및목적 - 지오그리드와 지오그리드와말뚝에의한연약지반보강효과 Ⅰ. 연구방법 치환을통한대심도의연약지반개량은비경제적이며굴토된초연약지반의처리는또다른환경적인문제를야기시킴. 연약지반내에토목합성섬유로보강된말뚝기초에성토하중이재하될 경우, 말뚝으로보강효과, 말뚝과지오그리드로인한보강효과, 말뚝간격 별지오그리드로인한보강효과를도출하기위해 Pilot Scale 현장시험 연약지반에말뚝을타입한후성토를하게되면, 말뚝캡사이의연약지반이 시공을실시. 침하되어성토지반속에서지반파괴로인한부등침하가발생. 성토재 : 화강풍화토 연약지반이나불량매립지를통과하는제방이나도로, 흙구조물건설시과 연약지반 : 해성점토 ( 지반의교란을고려하여전단강도와지반의균질성이회복할수있도록 3 개월의자중압밀기간을가짐 ) 다한부등침하를방지하고지지력을확보할수있는방안을개발하는데목적이있음. 말뚝 : 길이 160cm 직경 10cm 의철근콘크리트 캡 : 직경 15cm 로제작 3 4 v 지오그리드 Tensar 사에서제작한 BX1100 사용 연약지반위에성토되었을때침하특성을파악하고이연약지반에말 뚝및지오그리드로보강하였을때효과를분석하기위하여, 말뚝간격, 일반적으로지반보강용으로사용되어지는양축방향지오그리드를 4m X 12m 넓이로포설 지오그리드보강유무, 성토높이에따른지반거동을고찰 5 6 1

결론 Ø 말뚝간격이 45cm 인경우를기준으로지오그리드의보강효과로인 한지반강화효과로인한침하량이크게감소하였으며, 수치상으로지 오그리드보강지반은무보강지반에비하여침하량이약 63% 로 37% 정 도감소되는것으로나타남. Ø 말뚝상부에작용하는하중이말뚝사이보다상대적으로크게작용되 어토압은증가되었으며, 지오그리드의변형률은크게발생되었다.

2 ü 말뚝간격이 4b 이상일경우말뚝타입간격이상대적으로넓어지오그리드 ü 말뚝위에설치된지오그리드의변형률이말뚝사이의변형률에비하여, 변형량 보강에따른하중분산없이처짐에의해침하가발생. 이많아인장력이크게발생. ü 4b 이하일경우말뚝이지오그리드를구속하여성토에의한하중이지오 ü 말뚝간격이클수록말뚝사이에지오그리드는처짐이발생되고, 말뚝상부의지 그리드의인장력으로분산되에침하량이급격히감소된것으로판단. 오그리드는말뚝의간섭으로인하여보다큰인장력이발생되는것으로판단됨. 7 8 Ⅳ. 결론 Ø 말뚝간격이 45cm 인경우를기준으로지오그리드의보강효과로인 한지반강화효과로인한침하량이크게감소하였으며, 수치상으로지 오그리드보강지반은무보강지반에비하여침하량이약 63% 로 37% 정 도감소되는것으로나타남. Ø 말뚝상부에작용하는하중이말뚝사이보다상대적으로크게작용되 어토압은증가되었으며, 지오그리드의변형률은크게발생되었다. 이 러한현상은연약지반이침하되면서지오그리드의상부하중이말뚝상 ü 말뚝상부토압은간격이작을수록증가하며, 말뚝사이의토압은간격이클 부에전위되었기때문인것으로판단됨. 수록감소하는경향을보임. ü 이는말뚝이지지층까지타입되어더이상의침하가발생하지않고말뚝사이의연약지반은침하가발생하여지오그리드위의성토하중이지오그리드를통해말뚝상부로전달되기때문. Ø지오그리드가말뚝상부에위치할때연약지반상에축조된제방의기초지반보강효과가매우큰효과가있는것으로판명 Ⅰ. 논문배경및목적-Embankments reinforced by piles and geosynthetics Fpiles= 파일에의해지지되는하중 Ftot = 제방의무게와가해지는하중의전체하중 Fig. 1. Mechanism acting in an embankment reinforced by piles and geosynthetics 말뚝과토목합성섬유에의한지반보강매커니즘을분석 ( 캡의크기, 토목합성섬유의강성, 성토높이, 기초지반의강성 ) 수치모델과현장실험결과치를분석하여성토체의하중이하부기초에전달되는특성을파악하는데목적이있음. Fig. 3. Studied geometry. Ea = Efficacy of the transfer of load Eg = Efficacy of the geotextile Es = Efficacy of the ground support Ep = Efficacy of the reinforcement Ep = Ea + Eg, Es=

Influence of the size of the piles caps Fig. 10.

displacement of the geosynthetic sheet. Fig. 11.

Influence of the geosynthetic stiffness on the vertical displacements of the sheet on view a (see Fig.

Influence of the stiffness of the geosynthetic sheet on the efficacy and on the maximum displacement.

3 Influence of the size of the piles caps Fig. 10. Influence of width of the piles cap on the vertical displacements of the geosynthetic sheet on view a (see Fig. 3). Fig. 9. Influence of width of the piles cap on the efficacy of the transfer of load and on the maximum displacement of the geosynthetic sheet. Fig. 11. Influence of width of the piles cap on the vertical displacements of the geosynthetic sheet on view b (see Fig. 3) Influence of the stiffness of the geosynthetic sheet Fig. 13. Influence of the geosynthetic stiffness on the vertical displacements of the sheet on view a (see Fig. 3). Fig. 12. Influence of the stiffness of the geosynthetic sheet on the efficacy and on the maximum displacement. Fig. 14. Influence of the geosynthetic stiffness on the vertical displacements of the sheet on view b (see Fig. 3) Influence of the underlying compressible soil Fig. 16. Influence of the compressible soil on the vertical displacements of the geosynthetic sheet on view a (see Fig. 3). Fig. 15. Influence of the compressible soil on the efficacy of the transfer of load and on the maximum displacement. Fig. 17. Influence of the compressible soil on the vertical displacements of the geosynthetic sheet on view b (see Fig. 3)

Influence of the embankment height Fig. 19.

on view b (see Fig. 3). 19 20 Fig. 24. Study s geometry of Carlson (1987) method. Fig. 26.

Study s geometry of SINTEF (2002) method. Fig. 27. Study s geometry of Kempfert et al.

4 Influence of the embankment height Fig. 19. Influence of the embankment height on the vertical displacement of the geosynthetic sheet on view a (see Fig. 3). Fig. 18. Influence of the embankment height on the efficacy of the transfer of load. Fig. 20. Influence of the embankment height on the vertical displacement of the geosynthetic sheet on view b (see Fig. 3) Fig. 24. Study s geometry of Carlson (1987) method. Fig. 26. Study s geometry of Hewlett and Randolph (1988) method. Fig. 25. Study s geometry of SINTEF (2002) method. Fig. 27. Study s geometry of Kempfert et al. (1997) method Fig. 32. Geometry of the piles distribution. Fig. 28. Efficacy of the piles depending on the geometry of the embankment

Fig. 35. Geometry of the numerical model. Fig. 34.

Membrane behaviourof the geosynthetic. 25 26 Ⅳ.

그리고남아있는하중은토목합성섬유와하부지반에의해지지된다. Fig. 37. B (see Fig. 35).

27 28 v 연안역과제에서의활용 Ø 기포콘크리트의말뚝에의한하부기초설계에서가장문제시되는말뚝간격이좁아

5 Fig. 35. Geometry of the numerical model. Fig. 34. Membrane effect observed over the pile. Fig. 39. Membrane behaviourof the geosynthetic Ⅳ. 결론 독립적인비점착성재료로만들어진제방의하중전달매커니즘은지반 보강용흙과토목합성섬유의강성에따라달라진다. Fig. 36. Vertical displacements of the geosynthetic sheet on view A (see Fig. 35). Fig. 38. Vertical displacements of the geosynthetic sheet on view C (see Fig. 35). 토목합성섬유의구조적형상에의해말뚝으로하중이전달되는영향을받게되고, 이는말뚝에의한네트워크와토목합성섬유에의한커버리지비율, 제방의높이등의상태에따라달라진다. 그리고남아있는하중은토목합성섬유와하부지반에의해지지된다. Fig. 37. Vertical displacements of the geosynthetic sheet on view B (see Fig. 35). 제방기초의수직변위의거동은기초보완역할을하는토목합성섬유시트와기초지반과연계되어지며, 변위의거동을감소시켜준다. 만약기초지반이초연약지반일경우에는앞서연구에서이용된 design rule에따라토목합성섬유의최대변위값을예측할수있을것이다 v 연안역과제에서의활용 Ø 기포콘크리트의말뚝에의한하부기초설계에서가장문제시되는말뚝간격이좁아 지면서비용이과다하게증가하는문제와기포콘크리트의인장력에의한파손문제 ü말뚝상부에토목합성섬유를설치하여말뚝으로의하중전달에의한원지반이받는하중을저감시키고, 말뚝간격s의증가를도모하여경제적인시공을가능케함. ü토목합성섬유의분리재, 배수재, 필터, 차단재등의역할을기대하므로서또다른효과를도모 Thank you

<INPUT DATA & RESULT / 전단벽 > NUM NAME tw Lw Hw 철근 위치 Pu Mu Vu RESULT (mm) (mm) (mm) 방향 개수 직경 간격 (kn) (kn-m)

<INPUT DATA & RESULT / 전단벽 > NUM NAME tw Lw Hw 철근 위치 Pu Mu Vu RESULT (mm) (mm) (mm) 방향 개수 직경 간격 (kn) (kn-m) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 NUM NAME tw Lw Hw 철근 위치 Pu Mu Vu RESULT (mm) (mm) (mm) 방향 개수 직경 간격 (kn) (kn-m) (kn) 휨 전단 축력 종합 1 2W1 300 3400 4500 수직 2EA- D13 @150