Time effects on stress-strain relationships of Bangkok soft clay | |
| Author | Nguyen Thanh Nhan |
| Call Number | AIT Thesis no. GT-91-17 |
| Subject(s) | Clay soils--Thailand--Bangkok Clay--Thailand--Bangkok |
| Note | A thesis submitted in partia l fulfillment the requirement for the Degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GT-91-17 |
| Abstract | The influence of time effect on the stress-strain behaviour of Bangkok soft clay as tested in the triaxial app~ratus under different applied stress paths and under different periods of aging are presented in this study . Undisturbed samples were taken from depths of approximately 3m to 5m below the ground surface. Stress control l ed triaxial tests were conducted in the equipment where in piston friction is reduced to a minimum by rotating the bushing. Two series of test programme included (i) Isotropic consolidation tests (CIU & CIUE tests) (ii) Anisotropic consolidation tests (CAU & CAUE tests) Two series of triaxial tests on samples which were normally consolidated for different periods of time, such as one day, seven days and thirty days, prior to the subsequent shear test. The specimens in test series II were conso lidated in different stress ratio such as ~ =0.43, ~ =0.23 , and ~ =-0 . 21 . Each series of test was carried out under both compression and extension conditions . The initial pre-shear void ratio of al l the samples is kept constant to about 2 . 7 . Comparison of the time effec t on the stress-strain behaviour between the compression and extension tests under t he same preshear consolidation pressure (test series I) are made for undrained tests. The results from the undrained loading test on soft clay under isotropic consolidation were also compared with the corresponding data obtained under anisotropic consolidation, that were affected by the time of aging. In a broad sense, the data con firmed that the time affected the normalized stress-strain relationships and the associated critical state line. The normalized stress-strain behaviour and the state paths followed by the specimens are found not to be the same for all specimen s which were conso lidated in different periods of time and sheared under similar applied stress pat hs. For two series of tests, the average value of critical state parameter M of the failure enve l ope and the angle of internal friction in compression tests are 1.08 and 27° respectively . Similarly for extension tests, the value of M and~ are 0.92, 33° respectively. It is shown that t he behaviour of the clay when sheared depends on the "age " of the samples. With time the clay becomes more brittle with smaller failure strains and the undrained shear strength shows a slight increase |
| Year | 1991 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GT-91-17 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical and Transportation Engineering (GT) |
| Chairperson(s) | Balasubramaniam, A.S.; |
| Examination Committee(s) | Tian Ho Seah;Honjo, Yusuke;Bergado, Dennes T.; |
| Scholarship Donor(s) | Ecumenical Scholarship Programs (BfdW); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology |