A case study on slope instability of Punatshangchhu Hydroelectric Project Authority-I Dam in Bhutan


  • Rinchen Lhamo Hydropower Research & Development Centre




Rock slope, shear zone, slope stability, subsurface profile


The stability of the slope is a greater concern to engineers and geoscientists as the socioeconomic consequences of the failures are huge. One such case is the slope instability of right bank of Punatshangchhu Hydroelectric Project Authority (PHPA-I) dam, Bhutan. The main geology of dam site is characterized by coarse-grained quartzo-feldspathic and biotite- muscovite gneiss. Since the start of the project in 2008, project encountered several geotechnical problems. During excavation at dam pit area, the shear zone got day-lighted which triggered a huge movement of right bank of dam in 2013. As such, project authority has carried out various stabilization measures in arresting movement of right abutment of dam. In this paper, subsurface profile construction from boring log data using Rockwork software (Rocscience) for PHPA-I dam site is presented. The subsurface profile once constructed can be used for identifying the critical slip surface and can also be used in modeling for slope stability analysis. Moreover, it can be a database for future use in that part of the study area.

Author Biography

Rinchen Lhamo, Hydropower Research & Development Centre

Ms Rinchen Lhamo did her Bachelors from College of Science & Technology in Civil Engineering in 2010. She then started her professional career as an assistant engineer at Druk Green Power Corporation limited (DGPC). During her tenure as engineer, she was largely involved in looking after the civil capital works and running & maintenance works of Chhukha Hydropower Plant. Before pursuing her masters, she also served at 720 MW Mangdechhu Hydroelectric Project Authority for one year, which was then under construction, on secondment from DGPC. While at MHPA, she was involved in supervision of Underground Powerhouse Complex and Pothead Yard. She completed her Masters of Engineering in Geotechnical & Earth Resource Engineering from Asian Institute of Technology, Thailand (2019). Currently she is working under Centre of Excellence for Civil & Geotechnical Engineering under Hydropower Research & Development Centre. Her current research interest includes geotechnical investigation & geotechnical instrumentation & monitoring.




How to Cite

Lhamo, R. . (2022). A case study on slope instability of Punatshangchhu Hydroelectric Project Authority-I Dam in Bhutan. Bhutan Journal of Research and Development. https://doi.org/10.17102/bjrd.rub.10.2.011