Anisotropic Shear Behavior Of Jointed Rock Masses At Ulu Jelai Hydroelectric Project, Pahang

• Main Author: Sapari, Nur Khafiza
• Format: Thesis
• Language: English
• Published: 2018
• Subjects: T Technology; TA401-492 Materials of engineering and construction. Mechanics of materials
• Online Access: http://eprints.usm.my/44262/1/Anisotropic%20Shear%20Behavior%20Of%20Jointed%20Rock%20Masses%20At%20Ulu%20Jelai%20Hydroelectric%20Project%2C%20Pahang.pdf; http://eprints.usm.my/44262/
• Institution: Universiti Sains Malaysia

Sifat ricih anisotropik untuk jasad batuan berkekar adalah salah satu isu penting dalam bidang kejuruteraan terutamanya dalam bidang pembinaan dan pembangunan. Kajian ini tertumpu pada keadaan geologi, kekuatan batuan dan keadaan tegasan in situ. Kajian ini telah dijalankan di projek empangan hidroelektrik di Ulu Jelai, yang dibina berdekatan dengan Cameron Highland, Pahang. Satu empangan konkrit berpemadatan guling (RCC) dengan ketinggian 88 m telah dibina bersama 22 km terowong pengalihan sebagai sebahagian daripada struktur empangan. Jasad batuan di kawasan kajian adalah agak sukar untuk dikaji kerana siri serantau yang berulang dan ricih. Secara geologinya, Cameron Highland terdiri daripada lineamen BL, TL and US dan dipotong dengan arah BL, TL and US jika dilihat dari bukti pergerakan Cenozoic. Berdasarkan dari kajian lapangan terkini, sebahagian sesaran ini adalah bukti pergerakan Quaternary Pleistocene sehingga Holocene. Pada masa yang sama, arah sesaran utama Semenanjung Malaysia adalah terarah kepada U-S, UBL-STG, BL-TG, BBL-TTG, B-T, TTL-SBD dan TL-BD. Berdasarkan ujian kekuatan mampatan uniaxial (UCS) menunjukkan jumlah julat antara 0.5 – 96.0 MPa manakala ujian Brazilian (BTS) jumlah julat antara 0.5 – 14.31 MPa. Daripada ujian tegasan in situ pula menunjukkan rekahan yang terhasil di dalam lubang yang telah di gerudi dan rekahan yang dihasilkan semasa ujian hidraulik menunjukkan corak yang sama dengan corak sesaran utama di Semenanjung Malaysia. Magnitud dan arah rekahan juga telah ditentukan sewaktu kajian analisis di mana tegasan melintang maksimum adalah kira-kira 6 MPa yang mempunyai arah normal dari paksi empangan yang mempunyai nilai penghampiran 30⁰ dan pseudo mendatar mempunyai kekuatan kira-kira 4 MPa. Satu korelasi telah dibuat merujuk kepada data yang diperolehi di mana terdapat hubungan yang kuat antara orientasi regim tegasan utama di Susu Dam dengan corak sesaran utama di Semenanjung Malaysia. Korelasi antara kualiti jasad batuan yang diperkenalkan oleh SMEC dengan sistem Penilaian Jasad Batuan (RMR) yang diperkenalkan oleh Beiniawski juga telah ditentukan dalam kajian ini. Daripada pemerhatian, sistem yang dibuat oleh SMEC adalah terhad kepada tahap proses mylonitision sahaja sementara sistem RMR adalah lebih umum dan boleh digunakan secara meluas untuk kebanyakan keadaan batuan. _______________________________________________________________________________________________________ The anisotropic shear behavior of jointed rock mass is one of the crucial issues in engineering field especially to the construction and developments. This research focused on the geological condition, rock mass strength and in situ stress state. The research has been done at Ulu Jelai Hydroelectric Dam project, which currently constructed near Cameron Highland, Pahang. An 88 m height of roller-compacted concrete (RCC) of dam is build with 22 km diversion tunnel as a part of dam structure. The rock mass is very difficult due to repeated regional series of faulting and shearing. Geologically, Cameron Highland is characterized by NW, NE and N-S lineaments and cut by NW, NE and N-S by going through faults displaying evidence for Cenozoic movements. Recent field investigation has identified that some of these faults evidence for Quaternary Pleistocene to Holocene movements. On the other hand, major faults in the Peninsular Malaysia strike at N-S, NNW-SSE, NW-SE, WNW-ESE, E-W, ENE-WSW and NE-SW. The value of uniaxial compressive strength (UCS) test is in the range of 0.5 – 96.0 MPa while the Brazilian Tensile Strength (BTS) test is about 0.5 – 14.31 MPa. The in situ stress analysis shows that the fractures occur in the borehole and the induced fractures during the hydraulic fracturing test follows the major fault pattern of Peninsular Malaysia. The magnitude and the direction of fracture have been determined during this analysis study which is the maximum horizontal stress has been found approximately 6 MPa with the direction normal to the dam axis with an approximation of ± 30⁰ and the least pseudo-horizontal has been found approximately 4 MPa. The correlation has been made referring to the data obtained where there is a strong relationship between the orientations of principal stress regime at Susu Dam with the major fault pattern of Peninsular Malaysia. The correlation between the rock mass quality introduced by SMEC with the Rock Mass Rating (RMR) system introduced by Beiniawski also has been determined during this research. From the observation, the system developed by SMEC is limited to the degree mylonitisation while the RMR system is more general and can be widely used for any rock material conditions.