Electro-chemical changes in clay during electro-osmotic consolidation using copper and carbon electrode with PVD | |
| Author | Inthuorn Sasanakul |
| Call Number | AIT Thesis no.GE-99-11 |
| Subject(s) | Soil stabilization Electroosmotic dewatering Vertical drains |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-99-11 |
| Abstract | Electro-osmotic consolidation of Bangkok clay using copper and carbon electrode with prefabricated vertical drain (PVD) was studied. Laboratory testing programs were conducted on undisturbed and reconstituted sample in small cylinder cell and large consolidometer in order to assess the probable effectiveness of electro-osmotic treatment. The tests were pe1formed under voltage gradient 60 and 120 Vim with 24 hrs polarity reversal. The results indicated that the time to achieve 90% degree of consolidation induced by electro-osmosis ranges from 1.4 to 2.1 and 1.2 to 2.2 times faster the normal consolidation using PVD only for undisturbed and reconstituted sample. The faster rate of consolidation and higher magnitude of settlement was achieved at higher voltage gradient. Although carbon electrodes decomposed with time, it achieved faster rate of consolidation and more settlement than copper electrodes. Higher reduction of water content and increase in shear strength were obtained after electro-osmotic consolidation compared to using drain only, especially in treated soil using carbon electrode. The shear strength increased up to more than 100%. The liquid limit, plastic limit and plasticity index were also increased because of the increase of salinity. Due to the polarity reversal the change of pH values after the electro-osmotic treatment gave a contradiction between undisturbed and reconstituted sample of small cylinder cell. Reduction of pH values was found in undisturbed sample, whereas, the values were increased for reconstituted sample. The reduction of electro-conductivity of soil after electro-osmotic treatment was observed. The value of electro-conductivity seems to be directly proportional to current density. The current density was measured during the treatment time and found that the value was reduced with time and increased during polarity reversal. At the end of the test, the current density was observed to be smaller than the initial value. Slight increase of organic matter was also observed. Moreover, the temperature increased only a few degrees Celsius, which was not high even for the higher voltage gradient. |
| Year | 2000 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-99-11 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Bergado, Dennes T.; |
| Examination Committee(s) | Balasubramaniam, A.S.;Kinya Miura; |
| Scholarship Donor(s) | Asian Institute of Technology Partial Scholarship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2000 |