Investigating the efficiency of electrokinetic remediation and electrokinetic stabilization in the soft Bangkok clay | |
| Author | Pornpong Asavadorndeja |
| Call Number | AIT Diss. no.GE-04-02 |
| Subject(s) | Electrokinetics Soil stabilization--Thailand--Bangkok |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. GE-04-02 |
| Abstract | Applications of electrokinetics in the soft Bangkok clay were intensively investigated. The electrokinetic cells was specially designed and fabricated for 1-D electrokinetic experiments. Three series of electrokinetic experiments were performed to determine the basic electrokinetic properties, the application of electrokinetics as ground improvement technique and the application of electrokinetic as ground remediation technique in the soft Bangkok clay, respectively. In the first series, six electrokinetic experiments were carried out. The soil was subjected to different electrical gradients ranging from 25 to 200 V/m until 1 Pore Volume (PV) of effluent was attained. Results of the first series shows that the coefficient of the electroosmotic conductivity of the soft Bangkok clay is in the range of 6.3810-10 to 1.3810-9 m2/Vsec and the electroosmotic water transport efficiency lies between 1.9310-8 to 2.3410-8 m3/Asec. The unit energy consumption at 1 PV of effluent increases from 79.8 to 178 kWh/m3 as the applied electrical gradient increases from 75 V/m to 200 V/m. In the second series, two electrokinetic stabilization experiments were conducted. The soil strength was improved by electrokinetically injecting the calcium ions under the electrical field of 200 V/m for 2 days. The efficiency of the electrokinetic stabilization was enhanced by introducing the anode depolarization technique. The hydrogen ions, which hinder the stabilization mechanisms, were prevented to migrate into the clay by depolarizing the anode reservoir. Increases in strength of up to 170% immediately after treatment and up to 570% after a seven-day curing were measured. The energy expenditure per unit volume was less than 120 kWh/m3. In the last series, four electrokinetic remediation experiments were performed. The experiments were carried out by applying a direct-current electric field of 200 V/m through the soil contaminated with Zn(II) at the level of 1,000 mg/kg for 7 days. In addition, the cathode depolarization technique, in which hydroxide ions generated from electrolysis reactions are eliminated by adding acidic solution into a cathode reservoir, was introduced to improve the efficiency of electrokinetic remediation. The experiment results showed that electrokinetic remediation was able to remove 82% of the contaminants in a period of one week, only. During this period, the combination of electrokinetic remediation with the cathode depolarization technique has raised the removal efficiency after 7 days of the treatment from 82% to 95% while the energy expenditure was slightly increased from 273 to 301 kWh/m3. Based on these experiment results, the electrokinetic stabilization and the electrokinetic remediation could be used as the economic and effective ground improvement technique as well as ground remediation technique for the soft Bangkok clay. |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. GE-04-02 |
| Type | Dissertation |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Glawe, Ulrich; |
| Examination Committee(s) | Bergado, Dennes T.;Noppadol Phien-wej;Pichai Nimityongskul;Czurda, Kurt; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2005 |