1999 Fiscal Year Final Research Report Summary
Secondary Consolidation of Ariake Clay
| Project/Area Number |
10660232
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
TAKAYAMA Masateru Kyushu University, Faculty of Agriculture, Professor, 農学部, 教授 (60038312)
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| Co-Investigator(Kenkyū-buntansha) |
HIYAMA Hiroki Kyushu University, Faculty of Agriculture, Assistant Professor, 農学部, 助手 (10208788)
HIGASHI Takahiro Kyushu University, Faculty of Agriculture, Assistant Professor, 農学部, 助手 (00181066)
OTSUBO Masami Kyushu University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (80112316)
OKABE Tamenobu Kyushu University, Faculty of Agriculture, Research Assistant, 農学部, 教務員 (60091378)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Ariake Clay / Secondary Consolidation / Clay Mineral / Coefficient of Secondary Compression / Coefficient of Earth Pressure at Rest / Compression Index / Swelling Index / Settlement Prediction |
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| Research Abstract |
1. Coefficient of secondary compression of clay : Effects of major clay minerals on the coefficient of secondary compression (CィイD2αeィエD2 were examined. The value of CィイD2αeィエD2 was constant for kaolinite, halloysite, and sericite while showed a maximum for bentonite and Ariake clay against an increase of consolidation pressure. The ratio of CィイD2αeィエD2 against compression index CィイD2cィエD2 was constant for kaolinite, halloysite, and sericite while decreased for bentonite and Ariake clay when the consolidation pressure was increased. Thus, the secondary consolidation-related characteristics for remolded clay exhibited did not exhibit a regular tendency, but differed whether smectite was present in the clay as a primary mineral. The value of CィイD2αeィエD2/CィイD2cィエD2 for undisturbed clay showed a maximum at consolidation yield stress, PィイD2cィエD2, and exhibited almost constant above this stress level. The average of CィイD2αeィエD2/CィイD2cィエD2 was 0.0392 with confidence intervals of 0.029 to 0.04
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9 which was within a range proposed by Ladd.
2. KィイD20ィエD2, λ, κ : The values of KィイD20ィエD2, λ, and κ needed for deformation analysis were assessed using the consolidation test apparatus which is capable of measuring horizontal stress. The value of KィイD20ィエD2 showed the minimum of 0.2 to 0.5 at around a consolidation yield stress, pィイD2cィエD2, and increased with increasing consolidation pressure above pィイD2cィエD2, but was almost constant (0.45 to 0.65) above 4 to 6 pィイD2cィエD2. The value of λ estimated from the value of CィイD2cィエD2 in one-dimensional consolidation tests gave overestimation. The following equations were obtained for Ariake clay : λィイD2cィエD2=0.521 *-1.08, κ/λ≒0.1, where f denotes volume ratio.
3. Prediction of settlement from in-situ data : Hyperbolic curve and Hoshino's method are available to predict settlement of clay from in-situ test data. Equations in those methods are represented as an upward convex hyperbolic curve when the equations are obtained in terms of dS/dlogt-logt, where S is the amount of settlement and t is time. The plotted settlement data showed a straight line which was away from the hyperbolic curve after a certain time tィイD2sィエD2. Therefore, the prediction of settlement was carried out by the hyperbolic curve method until tィイD2sィエD2 and the settlement was assumed to be proportional to logt after tィイD2sィエD2. These produced good results. Effects of pore water salinity on consolidation characteristics of clay and deformation analysis of Ariake clay ground were also studied. Less
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Research Products
(4 results)
