abstrak tugas geoteknik.pdf hu
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Tugas Geoteknik abstract
ABSTRACT
The traditional mining; it is located in Bantul district, the southeast of Yogyakarta special
province in Indonesia. The main problem that may occur in the mining traditional is risk and in
this area that contains 2 types of rock, i.e. andesitic breccias, and tuffaceous sandstone. Before
this underground structure will be constructed, the main problems that may occur during the
excavation need to be considered which relating to rock mass instabilities. Thus, to minimize and
avoid those problems, it is necessary to do the detail site investigation related to geological
conditions in order to estimate the rock mass quality in this area. This research is mainly aimed
to evaluate the rock mass quality by applying an empirical method as Rock Mass Rating (RMR).
The purpose of RMR system is to classify the quality of rock mass by using surface data which
are collected from totally forty five locations within the research area, in order to guide the
excavation method and also to give the recommendation of tunnel supports as well as the
unsupported span and stand-up time. Based on RMR determination by using surface data, the
qualities of rock masses in the study area are classified to be good and fair rock, the good rocks
are found on andesitic lava and andesitic breccias (RMR=70-77, unsupported span is 8.3 m,
stand-up time is 333.33 days); whilst fair rocks are found on pumiceous breccias and tuffaceous
sandstone (RMR=54.33-60.5, unsupported span is 6 m, stand-up time is 12.5 days).
Keywords: Rock Mass Quality, Rock Mass Rating, mining support requirement, Excavation
method.