Tanah terserak merupakan tanah bermasalah lantaran sifat semula jadinya yang mudah bertindak balas apabila terdapat kehadiran air lalu meningkatkan potensi hakisan cerun. Kewujudan ion natrium pada mineral lempung tanah melemahkan ikatan elektrokimia tanah terserak menyebabkan zarah lempung menolak dan menjauhi satu sama lain. Faktor ini mendorong pengasingan zarah tanah lalu membentuk fitur hakisan seperti ril dan galur rencam di permukaan bercerun, hakisan paip di dalam sub-permukaan landai dan kewujudan keruping merekah yang menjadi permasalahan dalam pembinaan struktur bangunan serta kejadian bencana alam. Kewujudan mineral lempung berbeza kapasiti pengembangan-pengecutan di kawasan tanah terserak menghasilkan morfologi dan sifat serakan tanah yang berbeza. Oleh itu, objektif kajian ini dijalankan adalah untuk mencirikan sifat fizikal tanah terserak tropika berdasarkan limpahan mineral lempung kaolinit dan montmorilonit serta hubungannya terhadap pembentukan morfologi hakisan cerun dan keruping tanah melalui pemerhatian lapangan dan analisis makmal. Hasil kajian mendapati kadar serakan dipengaruhi oleh sifat fizikal tanah seperti taburan saiz butiran, had cecair (LL), indeks keplastikan (PI), kandungan mineralogi lempung, nisbah % pasir/% zarah halus serta nisbah PI/LL. Analisis makmal menunjukkan tanah terserak dengan kehadiran mineral kaolinit dilihat kurang sensitif terhadap serakan berbanding mineral montmorilonit. Pemerhatian di lapangan mendapati tanah lempung kaolinit berasosiasi dengan pembentukan fitur hakisan ril dan galur rencam di sisi cerun secara lateral dan separa lateral, manakala tanah lempung montmorilonit tidak membentuk fitur hakisan yang nyata namun cenderung membentuk lapisan keruping dengan sistem jaringan rekahan heksagonal pada cerun bersudut hampir tegak (≈80°). Pencirian ini penting bagi meramal kewujudan dan taburan tanah terserak tropika berdasarkan limpahan mineral lempung yang berupaya menjadi pencetus kepada mekanisme geo-bencana yang sinonim berlaku di Malaysia.

The issue of radioactive waste disposal in Malaysia is frequently debated, particularly in terms of human and environmental long-term well-being. The creation of a repository with minimal hazard risk and cost implications is a major environmental concern related to nuclear waste. Expansive clay has distinct characteristics that are readily available in the environment and can serve as a natural barrier (sealing system) against the migration of radioactive and chemical pollutants. In this study, the physico-chemical and microstructural properties of 2 types of tropical soils with dominant clays mineral (vermiculite and montmorillonite) were investigated to better understand the potential of these clays as natural sealing in nuclear waste repository systems. Based on preliminary findings, both types of soil have been classified as alkaline soil (>7) with high swelling capacity (FSI) (>80%) and high consistency (LL>50%; PI>30%). The microstructural study demonstrates that vermiculite clays have a noticeable flaky morphology and a porous structure as compared to montmorillonite, indicating that the soil can absorb more water, hence decreasing its infiltration capability. Pinhole dispersion analysis reveals that montmorillonite clay is more prone to dispersion due to the presence of sodium ions and has a higher erosion potential than vermiculite clay. Future Malaysian stakeholders may employ this research to establish a long-term plan for the management of radioactive waste through the usage of natural resources.

Relative density is one of the most important properties indicating the strength and state of compaction of the soil. The dynamic cone penetration test is considered one of the fastest field tests for evaluating the relative strength of soil layers, including density. In this study, an attempt is made to correlate the relative density of the landslide soil with the dynamic cone penetration results. The aim of this study was to delineate the boundary between moving and in-situ soil for the prediction of slip surfaces and finally to conceptualise the underlying mechanism behind the initiation of a landslide. The results of the penetration tests give an increasing index of 1.9 - 2.4 cm/blow, 2.8 - 3 cm/blow and 3.2 cm/blow for the upper, middle and lower parts (toe), respectively. Using the correlation equation, the calculated relative density in the field was found to agree well with the relative density measured in the laboratory with a standard deviation of ±1.5%. The relationship between the relative density and the penetration index shows an inverse relationship where the resistance of the soil to dynamic penetration increases as the relative density of the soil increases, thus decreasing the penetration index. This result can be used to accurately conceptualize the mechanism behind a landslide using a simple and rapid field device.