KAJIAN PENERAPAN KLASIFIKASI MASSA BATUAN DENGAN METODA CRIEFI DI TEROWONGAN PEMBANGKIT LISTRIK JATIGEDE, KABUPATEN SUMEDANG, JAWA BARAT

• Main Author: Hadiyansyah, Dian
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/78839
• Institution: Institut Teknologi Bandung

Enginering geology investigation conducted at power waterway tunnel which is part of the Jatigede dam construction at Sumedang District, West Java. Tunnel construction penetrating two lithologies, Lower Member of Halang Formation and Undifferentiated Old Volcanic Products. The objective of this study is to apply the rock mass classification system by Central Research Institute of Electric Power Industry (CRIEPI) which originating from Japan and to analyze the relationship between rock mass classification and tunnel support system. Research stages consist of investigation and construction. Investigation stage consist of collecting data from 150 m drill core and 10 core samples for laboratory testing. Based on drilling result, RQD for volcanic breccia ranged between 60 - 8,25 % and claystone ranged between 62,5 - 85 %. Laboratory test result revealed UCS values from volcanic breccia ranged between 69,1 – 127,2 kgf/cm2 and claystone ranged between 36,9 – 108,9 kgf/cm2. Activities at construction stage is collecting 57 wall face data along power waterway tunnel. Rock mass classification result at investigation stage divide tunnel at three rock mass class, that is CM (0 – 21,5 m), CH (21,5 – 54 m), and CL (54 – 102 m). Rock mass classification result at construction stage showed the same rock mass class with different data distribution. Rock mass classification result between investigation and construction stages compared to observe accuracy of rock mass classification at investigation stage. Based on that comparison, the accuracy results for each class that is CM (20,11%), CH (47,05%), and CL (59,26%) Based on rock mass classification data on design stage, tunnel support system were proposed to maintain tunnel stability. The support system consist of rockbolt and shotcrete. The proposed support system was analyzed with finite element method in each rock mass class with two scenarios, tunnel without or with support system. Tunnel stability observed by major stress condition, the safety factor, and horizontal and vertical tunnel displacement. The results obtained for CH and CM classes are tunnel condition quite stable with proposed support system. While the CL class is in a less stable state with proposed support system.