| Author | Wichit Sriwisead |
| Call Number | AIT Thesis no. GE-95-25 |
| Subject(s) | Lam Ta Khong Project
|
| Note | A thesis submitted in partial fulfilment of the requirements for the degree of Master of
Science, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-95-25 |
| Abstract | The engineering geological mapping along the access tunnel to powerhouse and to
top gallery was carried out which helped classify the rock mass according to the most
popular classification systems namely RMR ,Q-system and EPDC. The rock mass turned
out to be mostly of fair quality and good quality for sandstone section. The deformation
modulus, cohesion and frictional angle, Hoek and Brown's m ands strength parameter and
others rock mass properties were approximated. The support recommendation from RMR
and Q-system were estimated that could be compared with the actually installed which was
recommed by EPDC. The convergence measurement was monitored and collected data
were analyzed, interpreted and the rock mass modulus of deformation was back calculated
by using the Phases analysis. The results of back calculation modulus of deformation of
sandstone was higher than siltstone (1.4-4 GPa for reddish siltstone and 4.3-42 GPa for
sandstone) and the intercalated of sandstone and siltstone showed high value. Modulus
deformation estimated from Phases analysis would be related well with modulus from Qsystem. The plastic zone was developed deeper behind inve1t and crown for highly
weathered siltstone and sandy siltstone up to 4-5 m. The rock mass showed time-dependent
behavior but the convergence rate decreased with time that insignificant. The estimated of
the convergence rate was less than the lower value for squeezing ground (0.07% at 1000
days for siltstone (0.042 mm/day), 0.09% at 1000 days (0.0054 mm/day) for sanstone and
0.15% at 1000 day or 0.006 mm/day for intercalated of both layer. Ground responses were
observed that several types were identified such as loosening, slaking, swelling, stress
slabbing, delayed fracturing etc. The Loosening was the most prominent as failure was
governed both by discontinuity systems and the low strength of rock mass itself. Slaking
though being very drastic outside the tunnel was not so severe inside of both access
tunnels. Stress slabbing including delayed with depth became noticeable due to excessive
strength ratio. The excavation and support performance was described of several suppo1t
types. The main supporting types was used of the system rockbolt and shotcrete that was
proved to be most suitable for each ground section. |
| Year | 1996 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-95-25 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Noppadol Phienwej ; |
| Examination Committee(s) | Sugimoto, M. ;Bergado, Dennes T.
|
| Scholarship Donor(s) | The Royal Thai Government ; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 1996 |