Study of the Applicability of a Drum Centrifuge to Model the Process Self-weight Consolidation of a Soft Clay

本研究以小型转鼓式离心机为研究对象，以便于观察软土的自重固结现象，并快速评估固结参数。本研究的主要成果可概括为以下七点：1）设计并建造了一台小型转鼓离心机。转鼓离心机直径为0.2 m，宽度为0.07 m，深度为0.065 m，可旋转至沉降数据随时间的变化通过表面沉降的目视读数获得。2）使用塑性指数为57.8、42.7、29.4和22.0的四种粘土，共进行了35次试验，3）用不同的深度和离心加速度组合进行三次试验，模拟10 m软层的相同原型行为。结果再次证实了模型的建模是成立的。4）为了研究周向应变对沉降行为随时间的影响，将安装在滚筒上的径向狭缝的数量从3个改变为9个，以划分试样。结果发现，数量有没有显着的影响的行为。5）进行了尝试，直接比较梁式离心机试验和转鼓试验获得的测试结果。在此基础上推导了弹性固结方程，并进行了求解。将分析结果与试验数据进行了比较，并从均布层弹性固结理论的角度对试验数据进行了解释。7）将多层体系的自重固结现象模拟为将一层粘土浆浇筑在另一层粘土浆之上，并进行固结。

This study developed a small drum centrifuge for easy observation of the phenomena of self-weight consolidation of a soft clay and quick evaluation of consolidation parameters. The results of this study may be summarized in the following seven points :1) A small drum centrifuge was designed and constructed. The drum centrifuge has a diameter of 0.2 m, a width of 0.07m, a depth of 0.065m and can be spun up to settlement data with time are obtained by visual readings of surface settlement.2) Four various clays with plasticity indices of 57.8, 42.7, 29.4 and 22.0 were used and 35 tests in total were conducted, confirming the repeatability of the tests.3) Three tests were carried out with different combinations of depth and centrifugal acceleration, modeling the same prototype behavior of a 10 m soft layer. The result reconfirmed that modeling of models is held.4) In order to examine the effect of circumferential strains on the settlement behavior with time, the number of radial slits installed in the drum, dividing the specimens, was changed from 3 to 9. It was found that the number has not a significant influence on the behavior.5) An attempt was made to do a direct comparison between the test results obtained from beam centrifuge tests and those from drum tests. Appreciably differences were noticed in both settlement-time, and e-log p relationships.6) An equation of elastic consolidation was derived based and solved. The analytical results were compared with the experimental data, interpreting the test data from the view of the elastic consolidation theory for a uniform layer.7) Phenomena of self-weight consolidation of multi-layered system were modeled by pouring a clay slurry overlaying another clay slurry being consolidated.