Pencirian Geomekanik Jasad Batuan dan Analisis Kestabilan Cerun di Laman Granview, Saujana Puchong, Selangor, Malaysia

Abdul Ghani Rafek, Bok Cheng Ong, Thian Lai Goh
2019 Sains Malaysiana  
ABSTRAK Satu kajian pencirian geomekanik jasad batuan dan analisis kestabilan dua cerun terletak di tapak pembinaan Laman Granview di Saujana Puchong, Selangor telah dijalankan. Kawasan kajian merupakan sebahagian Formasi Bukit Kenny. Kajian telah dijalankan pada dua buah cerun potongan di tapak binaan adalah survei ketakselanjaran dan pencirian mekanik batuan. Kuarzit adalah litologi yang dominan di kawasan ini dengan sedikit filit. Ujian mekanik batuan berikut dijalankan: Ujian kekuatan
more » ... jian kekuatan mampatan sepaksi, ujian indeks beban titik dan ujian kekuatan regangan Brazil, ujian pantulan tukul Schmidt dan ujian Skleroskop Shore. Ujian kemiringan untuk penentuan kekasaran permukaan satah ketakselanjaran dijalankan pada sampel bongkah batuan. Hasil survei ketakselanjaran menunjukkan terdapat empat set ketakselanjaran yang utama di cerun L1 dengan nilai arah kemiringan/sudut kemiringan 62°/42°, 261°/79°, 281°/59° dan 237°/71°. Di cerun L2, terdapat tiga set ketakselanjaran utama iaitu dengan nilai arah kemiringan/sudut kemiringan 81°/41°, 171°/71° dan 198°/60°. Untuk ujian kemiringan, nilai purata sudut geseran puncak (f p ) permukaan satah ketakselanjaran batu kuarzit dengan Pekali Kekasaran Kekar (PKK) 8-10 adalah 61°. Ketakselanjaran batuan kuarzit dengan nilai PKK 10-12 pula mempunyai purata sudut geseran puncak (f p ) sebanyak 73°. Manakala, nilai purata sudut geseran puncak (f p ) batuan filit dengan PKK 4-6 ialah 56°. Berdasarkan analisis kinematik, cerun L1 adalah stabil. Ragam kegagalan cerun L2 pula adalah kegagalan satah tetapi nilai sudut geseran permukaan satah yang tinggi akan menghalang kegagalan berlaku. Nilai perkadaran jasad batuan (RMR) bagi batuan kuarzit ialah 77 dan batuan filit ialah 66 dengan kedua-dua tergolong dalam batuan yang baik dalam kelas II. Kata kunci: Analisis kinematik kestabilan cerun; perkadaran jasad batuan (RMR); ujian kemiringan ABSTRACT A study was conducted at the construction site of Laman Granview, Saujana Puchong, Selangor to study the stability of two slopes and the geomechanical properties of the rock mass. The study site is part of the Kenny Hill Formation. Surveys were carried out at two cut slopes at construction site were discontinuity surveys and rock mechanics characterisation. Quartzite is the dominant lithology in this area with minor amounts of phyllite. The following rock mechanics tests were conducted: Uniaxial compressive test, point load index test, Brazilian tensile strength test, Schmidt rebound hammer test and Shore Scleroscope test. Tilt tests for determining the surface roughness of discontinuities were conducted on rock block. The results of discontinuities survey showed that there are four major sets of discontinuities at cut slope L1 with dip directions/dip values of 62°/42°, 261°/79°, 281°/59° and 237°/71°. At cut slope L2, there are three major discontinuities sets with dip direction/dip values of 81°/41°, 171°/71° and 198°/60°. For the tilt test results, the average peak friction angle (f p ) of the discontinuity surface for quartzite with Joint Roughness Coefficient (JRC) 8-10 is 61°. Discontinuity planes of quartzite with JRC of 10-12 have an average peak friction angel (f p ) value of 73°, while phyllite with JRC 4-6 has an average peak friction angle (f p ) value of 56°. Based on kinematic slope stability analysis, cut slope L1 is stable. Potential failure for cut slope L2 is plane failure but the high friction angle of the discontinuity surface will prevent failure. The Rock Mass Rating (RMR) obtained for quartzite is 77 and phyllite is 66 which both of which are classify as good rock mass in class II.
doi:10.17576/jsm-2019-4804-07 fatcat:2bqzkoucabdytkozbabeyesxny