Geologi di kawasan pantai Utara Semenanjung Malaysia kebanyakannya terdiri daripada deposit tanah liat lembut. Oleh yang demikian, aktiviti pembinaan di kawasan tersebut sukar dan mencabar. Dalam kajian ini, suatu kaedah baru bagi menilai kualiti tapak pembinaan, terutamanya dari segi penentangan terhadap penembusan telah diperkenalkan. Secara khususnya, data ujian penembusan (SPT) telah ditukar kepada nilai SPT N terkumpul untuk perbandingan antara tapak dan juga bertujuan untuk anggaran kos. Nilai SPT N yang diperolehi daripada ujian penembusan yang terdiri daripada tujuh tapak tanah liat marin dan empat tapak laterit telah ditukar kepada nilai SPT N terkumpul. Bacaan bagi nilai SPT N dipilih adalah daripada setiap kedalaman 1.0m. Garisan lengkungan daripada nilai SPT N terkumpul baru telah didapati lebih sesuai untuk penilaian berbanding yang sedia ada. Oleh itu, nilai SPT N terkumpul baru dapati lebih baik bagi menilai kualiti tapak. Dalam kajian ini, setiap tapak tanah liat marin yang dipilih digambarkan dengan menyatakan julat nilai SPT N terkumpul pada kedalaman 20m dan kecuraman garisan lengkungannya. Penilaian tanah lembut yang melibatkan tanah liat marin menunjukkan bahawa kualiti tanah dari segi nilai SPT N terkumpul berbeza sedikit sahaja bagi dua tapak yang mempunyai jarak berdekatan. Perbezaan dari segi julat nilai SPT N terkumpul pada kedalaman 20m meningkat dengan peningkatan jarak antara tapak. Nilai SPT N terkumpul bagi tapak tanah liat marin juga meningkat apabila jarak tapak semakin jauh daripada persisiran pantai atau laut. Nilai SPT N terkumpul juga lebih tinggi bagi tapak laterites berbanding tapak tanah liat marin. Oleh itu, penilaian tapak berdasarkan nilai SPT N terkumpul didapati lebih praktikal dan mempunyai potensi untuk digunakan dalam amalan geoteknikal.
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The coastal area geology of Northern Peninsular Malaysia is mostly defined by the soft marine clays deposits of the quaternary era which makes it challenging to construction activities. In this study, a new method of evaluating the quality of a construction site, mainly in terms of resistance to penetration was introduced. Specifically, the standard penetration test (SPT) data were converted into the cumulative SPT N-value curve for comparison between sites and cost estimating purposes. SPT N-value data obtained from Piezocone tests from seven marine clays sites and four laterite sites were processed and converted into the cumulative SPT N-value curves. The selected SPT N-value readings were from the 1m intervals. The new cumulative SPT N-value curve were found to be more suitable for evaluation than the normal SPT N-value curve could provide and therefore was found better at representing the quality of a site. In this study, each selected marine clay site was described by stating the range of cumulative SPT N-value at 20m depth and the steepness of the curve. The evaluation of soft ground involving the marine clays indicates that the quality of a ground in terms of the cumulative SPT N-values differ only slightly for two nearby points of the same site. The difference in terms of the range of cumulative SPT N-value at 20m depth increased with increasing distance between sites. The cumulative SPT N-value of a marine clay site also increased as the site located further inland from the sea. The cumulative SPT N-values were also higher for laterites sites than for marine clay sites. Thus the evaluation of a site based on the cumulative SPT N-value was found to be practical and has the potential to be used in the geotechnical practice.
Comparative evaluation of marine clays qualities based on SPT (N) results of CPTU test from northern region of Peninsular Malaysia / Nur Farizza Adnan