Origin and engineering characteristics of the problem soils in the Khorat Basin, Northeastern Thailand | |
| Author | Veerasak Udomchoke |
| Call Number | AIT Diss. no. GT-90-01 |
| Subject(s) | Sedimentation and deposition--Khorat Basin Sedimentation and deposition--Khorat Basin |
| Note | A dissertation submitted in partial fulfillment of the requirements for the Degree of Doctor of Technical Science, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. GT-90-01 |
| Abstract | The Quaternary sediments in the Khorat Basin , northeastern Thailand are comprised of residual soils, gravel beds , red and yellow loess , lake and swamp deposits , windblown sand s , flood deposits or old alluvium , recent alluvium, a nd man - made mounds . The soils in this area pose problems to the engineering works due to their collapsibility, erodibility and dispersiveness. The collapsible soils are red and yellow loess. They are grade d as severely col lap sib le du e to their high collapse potential ( 25% to 27% for yellow loess a n d 30% to 32% for red loess ) . Collapsing behavior of the loessal soils start at the moisture content between 5% to 7% (about 22% to 32% degree of saturation) , and at applied pressure of between 50 kPa to 120 kPa . Collapse mechanism is predominantly due to the fail u re of clay and iron oxide bridges between t h e sand a n d silt grains and the effect of capillary tension in the pores . The dispersive soils are main l y the residua l soil a nd t h e alluvium which are found in the low-lying area. _Montmorillonite is the major clay mineral of these units. Their pore- water extracted s how high SAR value ranging between 8.2- 1 9. 0, slightly basic pH , high electrical conductivity a n d large amount of sodium cations. Th e high - ground residual soil with high amount of montmorillonite , low dissolved cations in pore - water, low electrical conductivity, SAR value ranging between 0 .1 - 8.2, and slightly acidic pH is nondispersive. Th e erodibility is exhibited b y t he loessial soil s, windblown sand , flood deposit a nd soil of the man-made mounds due to their open packing and insufficient amount of clay content (< 13%) . Red and yellow loesses can be stabilized by compaction at the dry unit weight of 16.8 kN/m3 a nd 17.7 kN/m3 , respectively. Cl ay content of at least 13!h is required to stabilize the sandy soil under maximum compaction. The compacted dry unit weight of about 16 kN/m3 is adequate to stabilize the sandy soil with 1 7% (or more) clay content. In case of the dispersive sandy soil, erodible behaviour is observed if t he clay content is less t h a n 9% , while at clay contents between 9% and 13% both erodible and dispersive behaviours are observed. At clay con tents more than 13% only dispersive behaviour plays a major role. |
| Year | 1991 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. GT-90-01 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Geotechnical and Transportation Engineering (GT) |
| Chairperson(s) | Prinya Nutalaya; |
| Examination Committee(s) | Balasubramaniam, A.S. ;Gupta, Ashim Das ;Noppadol Phienwej ;Indraratna, Buddhima ;Paepe, R.V.A. ;Yong, Raymond N. |
| Scholarship Donor(s) | Government of Japan ; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1991 |