Soil-water characteristic curves (SWCCs) are important in terms of groundwater recharge, agriculture, and soil chemistry. These relationships are also of considerable value in geotechnical and geoenvironmental engineering. Their measurement, however, is difficult, expensive, and time-consuming. Many empirical models have been developed to describe the SWCC. Statistical assessment of soil-water characteristic curve models found that exponential-based model equations were the most difficult to fit and generally provided the poorest fit to the soil-water characteristic data. In this paper, an exponential-based model is devised to describe the SWCC. The modified equation is similar to those previously reported by Gardner (1956) but includes exponential variable. Verification was performed with 24 independent data sets for a wide range of soil textures. Prediction results were compared with the most widely used models to assess the model's performance. It was proven that the exponential-based equation of the modified model provided greater flexibility and a better fit to data on various types of soil.

The focus of this study was to investigate the effect of loess soil treated with lime on the lateral-seepage response. Three groups of box experiments were carried out to study the lateral-seepage effect under different types of loess-lime structures. Automated testing systems were designed to perform experiments and collect data. Additionally, numerical analysis of lateral-seepage impact and embankment settlement was performed. Finally, moisture content and settlement were monitored to quantify lateral-seepage effect results under corresponding loess-lime treatment. Results showed that loess-lime compaction piles and diaphragm wall structures could effectively prevent lateral seepage, and the latter was better. The simulated results are similar to the measured values of the box experiment, which indicates the accuracy of the simulation analysis and further supports the experimental results of this study.

Malaysia is a country that is located near the equator line with tropical climates which receives high abundant rainfall, averaging 2,400mm annually. This makes Malaysia prone to the landslide events as rainfall is one of the main triggering factors that can cause landslide. Landslides in Malaysia are mainly attributed to frequent and prolonged rainfalls, in many cases associated with monsoon rainfalls. Of these, Ulu Klang area has received the most exposure. The area has constantly hit by fatal landslides since December 1993. This paper is aimed to investigate the correlation between the effective working rainfall and soil water index (SWI) methods with the landslide events in Ulu Klang, Malaysia. In this study 15 landslide events that occurred in Ulu Klang areas between years 1993 to 2012 were investigated and analyzed using rainfall threshold based on effective working rainfall and soil water index (SWI) methods. The analysis results showed that these methods are significant tools that can be used to identify the rainfall critical threshold of landslide event.

This paper studied the anti-seepage ability of the modified loess by using attapulgite, which is abundant in local areas. The possibility of using the modified loess as the sustainable compacted soil liner material in a solid waste landfill was also considered in this research. The materials were then evaluated using Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and an Impermeability Mechanism (IM). The experimental results showed that the permeability coefficient of the attapulgite-modified loess decreases significantly with increasing attapulgite content. However, it becomes less significant when the attapulgite level approaches 10%. Both cases can meet the landfill impermeability requirements, based on the attapulgite content remaining at 10%, adding 15% lime or 5% cement, respectively. The triaxial consolidation and drainage experiment was carried out to investigate the shear strength of the materials under three different working circumstances. The stress–strain curves of each specimen were produced, as were the cohesion and internal friction angle values. This research lays the groundwork for using attapulgite-modified loess as a landfill lining material. It establishes a solid platform for future studies on attapulgite adsorption and purifying performance in landfills.

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Disposal of accumulated plastic waste daily is an exigent in solid waste management. Hence, this study investigated the possibility of utilizing plastics waste in paver block fabrication for the pedestrian walkway. The development of paver block containing recycled plastic was started with a trial mix in order to identify the appropriate method for paver block fabrication. Two methods which are heating and compression were observed during the trial mix before proceeding to full scale casting. Compression method was selected in the production of paver block for further test. There were two ratios of cement, sand and soil used in the design mix namely mixture A and mixture B. The plastic content used in each mix were 0%, 5%, 10%, 15%, 20%, 25% and 30% by weight of sand. Laboratory tests conducted on the specimen were compressive strength, water absorption and skid resistance. Both mixtures were compared in terms of compressive strength in order to select the appropriate ratio. The results showed that mixture B produced higher compressive strength compared to mixture A. Replacement of 5% recycled plastic exhibits the highest compressive strength for mixture B, however for economical consideration the replacement can be utilized up to 30% recycled plastic content. Based on the water absorption test, the recycled plastic increases the water absorption. However, the skid resistance of the paver block was found higher than the requirements. Therefore, paver block made of recycled plastic incorporating locally available material has the potential for use in the construction of pedestrian path.

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