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Peat is a well-known problematic soil associated with poor engineering properties because its engineering with low shear strength, highly compressible, high moisture content. The characteristics make it unsuitable for construction in its natural stage. Thus, this study determines the soil properties of untreated peat soil and assesses the changes in strength of the treated peat soil using the admixture of Coffee Husk Ash (CHA) and Coconut Fibre (CF). The percentage of CF used is 0.50%, 0.75% and 1.0% meanwhile the percentage of CHA used was 5%, 6%, and 7% by the weight of the soil sample. The peat soil for this study were retrieved from Mardi Pontian in Johor. Soil properties such as moisture content, bulk density, and the Atterberg limit have been tested. The result of the Standard Proctor test in this study determined the Optimum Moisture Content and Maximum Dry Density of soil samples. The strength of these samples has been determined by using the Unconfined Compressive Strength (UCS). The physical properties for untreated peat soil with the moisture content of 250%, organic content about 77%, the specific gravity was in the range of 1.48–1.8. The Atterberg limit for liquid limit is 230. The compaction test results has shown decrement in maximum dry density (MDD) but an increase in strength with the addition of CHA and CF in peat soil. According to the findings, 0.5% of Coconut Fiber improves the engineering properties of peat soil (CF). • Natural peat is an unsuitable material for construction. • The changes in strength of peat using CHA and CF. • With added 0.5% of CF increase the peat strength. [ABSTRACT FROM AUTHOR]

The mounting concerns, with regards to environmental contamination, have led to the need for a better understanding of carbon oxide emissions. The escalation in economic activities, as well as the rapid global population growth, has contributed towards a detrimental impact on the environment. This study delves into the curbing of carbon dioxide emissions, particularly in the context of the construction industry, using sustainable materials. The emphasis, of this investigation, is on the effect of carbonation, on the compressibility behaviour, of ground granulated blast furnace slag (GGBS)-treated kaolin clay. According to the results derived from a one-dimensional consolidation test, the compressibility attributes improved in tandem with the GGBS content. Generally, these results indicate that a greater GGBS content, and a prolonged curing time, gives rise to less compressibility behaviour of treated kaolin clay. It was also revealed that in comparison to the treated kaolin sample, the carbonated kaolin sample delivered a greater degree of compressibility. Thus, it can be surmised, that carbonation enhances the compressibility features of kaolin. • GGBS as an alternative additive to treat kaolin clay. • Determination the effects of PSD on kaolin clay treated with GGBS as a preliminary test of the soil. • PSD test via two different methods; conventional method and particle size analyser (PSA). • Smooth curve produced from PSA compared to the conventional method. [ABSTRACT FROM AUTHOR]

Debris flow caused high number of deaths among many of geohazard events in Malaysia due to the characteristics of sudden outburst and high energy density. This paper reviewed the initial mechanism and characteristics of existing debris flow in Malaysia. Almost all debris flows occurrence were initiated on natural terrains as opposed to other forms of landslides. Most of the events were induced by the rainfall. This is due to the geographic locations of Malaysia that lies on the equator with tropical climates and received abundant rainfall of 2400 mm annually. Intense and heavy rainfall increases the water content and pore water pressures within the residual soil that could trigger landslides. Thus, an intense and prolonged rainfall has become the major triggering factor for debris flow. This review article focus on clarifies the characterization of historical debris flow events that had an impact the infrastructure in Malaysia. In summary, this review attempts to systematically summarize the existing research on the mechanism of debris flow in Malaysia to provide further reference on debris flow prevention. Comprehensive understanding of the mechanisms and the behaviour of the debris flow will assist to the fundamental hazard and provide proper planning for structural measures. • The initial mechanism and characteristics of existing debris flow in Malaysia. • The effects are more severe due to the climate change and human activities. • Formation of natural dam also can produce a disastrous debris flow. • Reality ofthe occurrence in Malaysia known as cascading geological process. [ABSTRACT FROM AUTHOR]

Soil erosion is a captious environmental problem in regions of hot tropical climates, causing loss of land and natural disasters such as river sedimentation, flooding, and slope failures. Based on soil properties and their response to erosion agents, efforts have been made to develop simplified models and indices for the estimation of erosion. ROM scale is proven to be effective in forecasting risk levels for erosion assessment. However, the method requires soil sampling and laboratory experimentation, which is time-consuming and laborious, especially when analyzing huge areas. Therefore, this study aims to develop a relation between ROM scale and shear wave velocity estimated by the spectral-analysis-of-surface-waves (SASW) method. For this purpose, 36 soil samples were extracted, and twelve SASW tests were conducted at twelve sites identified along Sungai Langat. Soil particle distribution was carried out to calculate the ROM erosion index value for all the extracted soil samples. The fast Fourier Transform (FFT) algorithm was used to transform the time-recorded signals into the frequency domain, and the dispersion curves were generated after the masking process. The shear wave velocity erosion risk ranged from 10 m/s to 120 m/s, indicating critical risk and low risk, respectively. Low erosion risk levels were observed for high shear wave velocity values, representing a decaying pattern in exponential relation. The resulting correlation between ROM scale and shear wave velocity produced a coefficient of determination value of 0.71, indicating a strong relation. This study indicated the potential of shear wave velocity as an erosion risk index. • In-situ soil erosion risk assessment by SASW method. • Erosion risk around Sungai Langat is averagely moderate. • Correlation between erosion index and shear wave velocity exhibits a strong relationship. [ABSTRACT FROM AUTHOR]

Malaysia has experienced several slope failures in the past and vegetation is one of the solutions that can help to increase the stability of slopes by preventing erosion and providing interlocking forces in the soil materials. This study investigates the effect of vegetation on riverbank slope stability in Malaysia. The analysis was conducted to capture the pattern of changes in terms of the factor of safety (FOS) of slopes. Using Plaxis, a total of 24 models were constructed consisting of two methods of modelling namely node-to-node anchor and geotextile, which act as vegetation. The modelling results show that the slope safety factor changed according to the addition of vegetation to the slope. The existing slope conditions recorded a safety factor at the value of 2.97. The value then increased when plants were added by adopting the node-to-node anchor along the top of the soil with the highest factor of safety value of 2.99. On the other hand, the factor of safety of slopes with the application of geotextile also shows an increase of up to 3.185. Whereas for the slopes with the effect of rainfall, the factor of safety values dropped to 2.609 and increase to 2.96 when vegetation was applied. This study indicates that vegetation can improve slope stability and that the different types of roots can also affect slope behaviour. • Extreme rainfall causes greater impact toward slope stability. • Vegetation can provide a good slope protection. • Different types of vegetation will have different impact on the factor of safety of soil. [ABSTRACT FROM AUTHOR]

Techniques of pile installation such as jacking, dropping weight, vibration, and explosion were applied but these methods were discovered to have weaknesses, such as high friction resistance and high settlements. To overcome these problems, this study introduces new method of pile installation which is Jacking and Rotary method (J&R). The objective of this study is to determine pile behaviour for static load test using common method namely jacking (J), and a new method, J&R through the ultimate pile capacity achieved by both methods. A stainless steel 25 mm circular pile, a 50 mm circular pile and a screw pile were used as test piles for this investigation. To achieve the objectives, this study employed graphical methods such as Brinch Hansen 80% and Tangent method to determine the ultimate pile capacity for both piling installation methods. Results revealed that for jacking method, the highest ultimate pile capacity value for the 50 mm circular pile was 1.186 kN, whereas the 25 mm circular pile had the lowest pile capacity reading of 0.539 kN. Screw pile shows the reading of 1.068 kN for its pile capacity. While for J&R, the highest average for both graphical methods are screw pile with 0.683 kN, while the 50 mm circular pile produced the lowest pile capacity which was 0.491 kN. For 25 mm, pile capacity using J&R is 0.543 kN. Result shows the acceptable for J&R methods to be introduced with further investigation such as the response of pile under axial loading and others. • Command methods for piling installation which could lead the structure to fail. • Jacking and Rotary pile installation simultaneously turned and jacked into the ground. • Brinch Hansen 80% and Tangent method used to determine the ultimate pile capacity. • Results indicated the acceptable of J&R methods and suggest for further investigation. [ABSTRACT FROM AUTHOR]

As the population of the city is increasing, the scarce land available. Therefore, it is a need to consider an alternative way to support the development. Underground structures such as tunnel become a sustainable solution and widely used. However, tunnel construction leads to unpredictable circumstances, especially when advancing in the vicinity of pile foundations. Tunnel advancement leads to ground stress release. The ground stress redistribution gives additional loads in both horizontal and vertical directions to the nearby pile and risks jeopardizing the pile integrity. Many research focuses on tunnel affecting the pile in vicinity but a lack of study carried out for incoming pile affecting the existing tunnel. Therefore, this paper aimed to study tunnel–pile interaction by performing a parametric study of different construction sequences between the tunnel and pile by using numerical modelling. Parametric studies for pile-tunnel sequence and tunnel-pile sequence were carried out. The simulated model was first validated with previous studies prior to the parametric study. From the parametric results, it was found that the existing pile behaviour could be affected by a new tunnel construction in terms of horizontal stress, deflection and settlement. In opposite, a tunnel was not significantly affected by the new pile construction. This was confirmed by results from the induced stresses and bending moment in tunnel lining. The bending moment gives mirroring affect behaviour at the left and right sides of the tunnel indicating lining is stable although new piles are constructed in the tunnel vicinity with higher working loads. • Tunnel construction can cause a stress release of the surrounding soil and lead to excessive ground movement. • Parametric studies for pile-tunnel sequence and tunnel-pile sequence were carried out • Pile-tunnel sequence give significant effect towards the pile integrity • For the tunnel-pile sequence, least significant effect towards the tunnel [ABSTRACT FROM AUTHOR]