Andhika Sahadewa
Site characterization is one of the main important stages in dam construction. Frequently, its results guide type selections of dam, foundation, drainage curtain etc. Unfortunately, many still underestimate the importance of site characterization for dam design and allocate limited resources. This paper presents a case study of a rockfill dam construction in Indonesia highlighting the importance of site characterization, where putting aside more investigation in the early stage has imposed great consequences in the following stages, including the selection of seepage-reduction method. Conclusion : The M Dam construction is a good example when limited site characterization in the initial stage could have negative impact in the following stages. Having initial limited resource for site characterization, the extent of confined aquifer layer and weathered tuff layer was unidentified correctly. This resulted in incorrect decision in selecting dam foundation excavation level and the best solution for seepage-reduction method. Additional site characterization program had to be performed to propose new dam design after the results from trial grouting test for grout curtain construction was discouraging. The consequences in redesigning resulted in time and financial losses. Investing in considerable site characterization in the early stage can reduce uncertainties that eventually avoiding any bad impact.
Penerapan Karya Tulis
In dam design, site characterization, aside of providing engineering property values, should be able to capture the variability and complexity of geotechnical, engineering geology, hydrogeology conditions in the dam sites. This information plays critical role as it frequently becomes a basis in selecting different scenarios in the design. This paper presents a case study of a rockfill dam construction in Indonesia highlighting the importance of site characterization in reducing uncertainties. In the early construction stage, additional field investigation was performed and identified the presence of high-porosity confined aquifer layer below dam foundation. This finding urged that the initial design of grouting cur-tain wall could no longer be applied. Dam redesigning required considerable effort and resulted in time and financial losses. Investing in site characterization is believed to reduce uncertainties that eventually avoiding any imminent negative consequences.