構造系 76 号 カテゴリー Ⅱ 日本建築学会構造系論文集第 79 巻第 76 号 87-82424 年 2 月 J. Struct. Constr. Eng. AIJ Vol. 79 No. 76 87-824 c. 24 格子状地盤改良の格子間隔に対する地震時の沈下解析 SIMULATIONS OF SETTLEMENT ABOUT THE GRID SPAN OF GRID-FORM DEEP MIXING WALLS UNDER EARTHQUAKE 金田一広 津國正一 本多剛 内田明彦 Kazuhiro KANEDA Shoichi TSUKUNI Tsuyoshi HONDA and Akihiko UCHIDA For liquefaction countermeasure based on grid-form dee mixing walls the grid interval has conventionally been designed using the excess ore water ressure ratio or the FL value and conditions under which liquefaction does not occur in the ground within the grid. However in the case of seismic motions with a long duration such as that which occurred during the 2 earthquake off the Pacific coast of Tohoku used as a design seismic motion the increase in the excess ore water ressure in the ground within the grid becomes greater than that for a seismic motion with a shorter duration and an equivalent acceleration level. Centrifuge model vibration testing and numerical simulations were conducted to obtain the knowledge required for a erformance design focused on settlement occurring in the ground within the grid. The sands with different relative densities are usually in a structured overconsolidated and anisotroic state. The Suer/subloading Yield Surface Cam-clay model with rotational hardening SYS Cam-clay model is owerful for incororating these features. We found that the numerical simulations reroduced the exerimental data well. It is indicated that there is the ossibility of settlement evaluations under earthquake. Keywords : Liquefaction Grid-form dee mixing walls Numerical simulation. 2 23 4 G 5 6 SYS 7 FL 4 2 3 竹中工務店技術研究所 主任研究員 工博 Chief Researcher Takenaka Research & veloment Institute Dr. Eng. 竹中土木技術 生産本部 部長 工修 Senior Manager Technology & Production veloment Division Takenaka Civil Engineering & Construction Co. Ltd. M. Eng. - 87 -
2 5 5-5 - -5-2 2. 89 6G 8mm 53mm fc=.5n/mm2 23mm GA t=.9m GL-m 2m 8% 2m Dr=5% 4cm EW 5 K-NET EW 2 5 5-5 - -5-2 4m 5.25m 8m 5.25m 8m.5m 2m.5m 62cm 5 a m Dr=8% K-NET m Dr=5 57 gal 2 45 gal 3mm 2.5mm cm GL-m m 5CS SYS 7 7 3 K-NET 2a 2 57gal ' MD ln ' ' 2b M2 2 2 M MD ln MDln R MD ln R v ' M 3/ 2 ˆ ˆ ˆ Pd3 / e / M e Pe3 Pa 3 Pd2 Pa 2 R Pe2 R R U br 2 D 3 R U s ˆ mb v ˆ ˆ 2 3 4 s br mb Prager 88 S S / ' D
=3979kN/m 2 6 q q=m ' q ' q ' q 2 5 3 5 '.. m Vs -q 5m/s 2Hz z 47.9m y x 6.9m.m log D / e / M..m.m 4.m 8.m 8.m 2.m 5.25m B 2 2 ' R R M f f MD ln MD ln 5 v 2 e R R ' M 5.25m R A R 4 xy m m z cm 7.8g/cm 3 GL-m M NCL intercet N at =98 kpa a b c b r m b m.5.5.6.79.. 2.2. 3.. 8 2 5 5% Dr5 kpa 3 2 e G K K ' 6 2 =.82 =.5 =. =kn/m 2 Dr5% Dr8%..5454.5454. K..6.6. R..2.5. e.76.82.63.75 2.656 k m/sec 5. -4. -4.8-4 - E kpa 2.5 6.5 t/m 3 2.65 k m/sec. -2-89 -
4.9 35.8 3. 7 3.7.6 25.5 2.4 5.3 Dr5 4mm 3mm.2 5...... % 8 K-NET 7 4mm 35% EW 5mm 3% 6 5 Dr8 4 Dr5 3 Dr5 2 22mm... 5mm 22%. S 5 5 2 25 3 2 5 3 4 4 5 2 25 3 5 2 25 3 5 2 25 3 5 2 25 3 5 2 25 3 5 5 5 2 25 3 5 5 5 5 5 2 2 5 5 2 25 3 5 5 5 5 5 2 2 5 5 2 25 3 5 5 5 5 5 2 2 5 5 2 25 3 5 5 5 5 2 3 5 5 2 2 Dr5 82 Dr8
.2.8.6.4.2.2.8.6.4.2.2.8.6.4.2.2.8.6.4.2.2.8.6.4.2 5-e 5 5 2 5-a Pa2 Pa2 5 5 2 5-b 5 5 2 5-c 5 5 2 5-d 5 5 2 Dr5 Pe2 Pe2 Pd2 Pd2.2.8.6.4.2.2.8.6.4.2.2.8.6.4.2.2.8.6.4.2.2.8.6.4.2 8-e 5 5 2 8-a 5 5 2 8-b Pe3 Pe3 Pa3 5 5 2 8-c 5 5 2 8-d 5 5 2 Dr8 Pa3 Pd3 Pd3 5...35. 5 3 =+e Dr5 5.. E-.8..7.6 5 3 =+e Dr8 =+e - 82 -
8 GL-2m Dr5 Pa5-aPd5-d Pe5-e GL-6m 5% 5-e 7 7 5 5-a 3 8% 8-e Dr8 Dr5 Pa Pb Dr585-a8-a Dr5 Dr88-b 8 9 4 A B =+e Dr5.2 5 5 2 2 38gal - - -2-2 2 2 3gal 99gal - - -2 7gal -2 Dr5 Dr5 2 2 45gal - - -2-2 2 2 94gal - -2-2 Dr8 32gal - 822 75gal Dr8
GL-2m 6 Dr5 Asaoka A. Noda T. Yamada E. Kaneda K. and Nakano M.: An elasto-lastic descrition of two distinct volume change mechanisms of soils Soils and Foundations Vol.42 No.5. 47-57 22. 667-668 24. C Vol.7 No.3 3-32 24. Dr8 Dr5 Asaoka A. Consolidation of clay and comaction of sand An elasto-lastic descrition- Keynote lecture Proc. of 2th Asian Regional Conf. on Soil Mechanics and Geotechnical Engineering Leung et al. Singaore Aug. Vol2.57-95 23. 4. 5% 35% 8% 22% 5% 8% SYS 2. 2.48-484 23. Vol.9 No.42.46-48 996. Vol.44 No.3 2.9-2 998. 45 2 26..783-784 997. - 823 -
SIMULATIONS OF SETTLEMENT ABOUT THE GRID SPAN OF GRID-FORM DEEP MIXING WALLS UNDER EARTHQUAKE Kazuhiro KANEDA Shoichi TSUKUNI Tsuyoshi HONDA and Akihiko UCHIDA Chief Researcher Takenaka Research & veloment Institute Dr. Eng. Senior Manager Technology & Production veloment Division Takenaka Civil Engineering & Construction Co. Ltd. M. Eng. For liquefaction countermeasure based on grid-form dee mixing walls the grid interval has conventionally been designed using the excess ore water ressure ratio or the FL value and conditions under which liquefaction does not occur in the ground within the grid. However in the case of seismic motions with a long duration such as that which occurred during the 2 earthquake off the Pacific coast of Tohoku used as a design seismic motion the increase in the excess ore water ressure in the ground within the grid becomes greater than that for a seismic motion with a shorter duration and an equivalent acceleration level. Centrifuge model vibration testing and numerical simulations were conducted to obtain the knowledge required for a erformance design focused on settlement occurring in the ground within the grid. The sands with different relative densities are usually in a structured overconsolidated and anisotroic state. The Suer/subloading Yield Surface Cam-clay model with rotational hardening SYS Cam-clay model is owerful for incororating these features. We found that the numerical simulations reroduced the exerimental data well. It is indicated that there is the ossibility of settlement evaluations under earthquake. 24 年 ₃ 月 日原稿受理 24 年 ₈ 月 22 日採用決定 - 824 -