Author/Authors :
GOH, T. L. Universiti Kebangsaan Malaysia - Fakulti Sains dan Teknologi - Program Geologi, Malaysia , GHANI RAFEK, A. Universiti Kebangsaan Malaysia - Fakulti Sains dan Teknologi - Program Geologi, Malaysia , RAHIM SAMSUDIN, A. Universiti Kebangsaan Malaysia - Fakulti Sains dan Teknologi - Program Geologi, Malaysia , HARIRI ARIFFIN, M. Universiti Kebangsaan Malaysia - Fakulti Sains dan Teknologi - Program Geologi, Malaysia , BAIZURA YUNUS, N. Universiti Kebangsaan Malaysia - Fakulti Sains dan Teknologi - Program Geologi, Malaysia
Abstract :
The mechanical parameters such as Poisson ratio are input parameter for rock engineering especially in numerical modeling computer software. Seismic methods were utilized to determine Poisson’s ratio for fresh (grade I), slightly weathered (grade II), moderately weathered (grade III) and highly weathered (grade IV) rock masses. Poisson’s ratio for each layer of rock mass was determined based on average value of compressive wave (Vp) and shear wave (Vs) velocities at respective depth. Compressive wave velocities (Vp) were determined by seismic refraction method and shear wave velocities (Vs) were determined by spectral analysis of surface wave (SASW) method or multichannel analysis of surface wave (MASW) method. A total of 66 seismic tests were carried out on 9 rock mass slopes comprising 6 tests on 1 granitic rock mass slope at Quarry JKR, Bukit Penggorak, Kuantan, Pahang; 26 tests on 4 granitic rock mass slopes at Kuari Kajang Rock, Semenyih, Ulu Langat, Selangor; 12 tests on 1 granitic rock mass slope at Lebuhraya Silk Kajang (km 14.6) Selangor; 14 tests on 2 schistose rock mass slopes at Jalan Kuala Kubu Baru-Bukit Fraser (km 15), Selangor and 8 tests on 1 quartzitic rock mass slope at Section U10, Bukit Cherakah, Shah Alam, Selangor. From the seismic tests, the maximum values of Poisson’s ratio for grade I, II, III and IV rock masses were 0.295, 0.335, 0.355 and 0.364. The minimum values of Poisson’s ratio for grade I, II, III and IV rock masses were 0.215, 0.299, 0.334 and 0.337. The average values of Poisson’s ratio for grade I, II, III and IV rock masses were 0.274, 0.320, 0.345 and 0.345. The values of Poisson’s ratio for rock masses were increased when the weathering grade increased. The average values of Poisson’s ratio for grade II, III and IV rock masses increased 16.8%, 25.9% and 25.9% if compare to grade I rock mass. This scenario occurred because fracture changes on grade I rock mass were bigger when experienced weathering processes. The fracture changes became smaller when experienced weathering processes further on. No fracture change occurred on grade III rock mass when became grade IV rock mass
Keywords :
Multichannel analysis of surface wave , poisson’s ratio , seismic refraction , spectral analysis of surface wave
