Abstrak

Suatu kajian secara integrasi kaedah geofizik dan geologi kejuruteraan telah dilakukan ke atas cerun potongan di KM67, Lebuhraya Timur-Barat (Grik-Jeli) bagi memetakan profil luluhawa syis kuarza-mika di teren tersebut. Kajian ini merangkumi tanah dan batuan metamorf rantau bergred rendah hingga sederhana yang telah mengalami luluhawa yang hebat. Pencirian syis kuarza-mika ini melibatkan 2 survei utama; iaitu survei seismos biasan dan pencirian bahan terluluhawa berdasarkan pengelasan kejuruteraan. Survei seismos biasan dilakukan pada hampir kesemua teres di lapangan menggunakan alat 24-saluran model ABEM Terraloc Mk3 dan geofon berfrekuensi 14Hz. Tafsiran data seismos kemudiannya dilakukan berdasarkan korelasi antara aspek petrofizik sifat fizikal bahan terluluhawa dengan kontras halaju gelombang P dan gelombang S yang diperolehi. Beberapa sifat kejuruteraan bahan terluluhawa juga telah dikaji bagi mencirikan gred luluhawa secara terperinci. Di antaranya ialah sifat fizik dan mekanik tanah seperti kandungan air, spesifik graviti, taburan saiz butiran dan had Atterberg bagi bahan tanah; keliangan, ketumpatan, kekerasan skleroskop Shore, indeks kekuatan beban titik, kekuatan tensi sepaksi dan ujian mampatan sepaksi bagi bahan batuan. Pengukuran halaju denyut ultrasonik dan modulus kenyal juga dilakukan ke atas sampel teras batuan syis untuk menentukan sifat fizik dinamik jasad batuan syis kuarza-mika. Kajian integrasi yang dilakukan telah dapat mencirikan profil luluhawa batuan syis kuarza-mika dengan terperinci dan berjaya mengemukakan beberapa hasil kajian yang memuaskan. Antaranya ialah peta profil luluhawa yang merangkumi cerun potongan di kawasan kajian, korelasi yang rapat di antara halaju seismos dan sonik dengan gred luluhawa, hubungan di antara modulus-modulus kenyal batuan dengan halaju denyut ultrasonik (gelombang P dan S) serta mengemukakan dan membincangkan hasil ujikaji yang merangkumi aspek fizik, mekanik dan mineralogi bahan terluluhawa yang berbeza-beza.

[ English Version ]

Integration of Geophysics and Engineering Geology in Determining the Weathering Profile of Quartz-Mica Schist at KM 67 Terrain, East-West Highway, Grik-Jeli, Perak-Kelantan

Abstract

An integration study of geophysics and engineering geology has been adopted in determining the weathering properties of the quartz-mica schist on a cut slope at KM 67, East-West Highway. They are consists of rock and soils of low to medium grade metamorphic rock in which had undergone strong weathering. Characterization of the quartz-mica schist consists of 2 main surveys; they were the engineering classification for profiling of rock materials and refraction survey method. The seismic refraction technique has been conducted using the ABEM Terraloc Mk3 seismograph and 14Hz geophones to characterize weathered materials based on velocity anomalies produced by various degree of weathering and types of weathered materials. The interpretations of seismic data later were made based on a correlation between petrophysics aspect of physical properties of the weathered materials and the velocity contrasts in the P- and S wave. Some engineering properties of rocks and soils were also conducted to characterize the weathered materials. The physical and mechanical properties of various weathered rocks and soils studied are as follows: water content, relative density, grain size distribution, the Atterberg limits (soil properties); and porosity, density, Shore hardness, point load strength, uniaxial tensile strength and uniaxial compressive strength for various weathered and fresh rocks. Measurements of ultrasonic pulse velocities of compressional and shear waves were also carried out on core samples of quartz-mica schist to determine the physical-dynamic properties of the material. This integration method has successfully characterize the weathering profile of quartz-mica schist in detail and the results obtained were very encouraging. They were the weathering profile map which consists of the main cut slope, a correlation between seismic and sonic velocities with the weathering indices, relationships between the elastic moduli of quartz-mica schist with the ultrasonic pulse velocities (P and S wave) and highlights of various physical, mechanical and mineralogical properties of materials of different weathering indices.