An Investigation of an Embankment Failure in Soft Clay

A number of embankment founded on soft clays have become unstable during construction of a major highway project in Malaysia. One of the embankment was back analysed based on its geometry before the failure. Measured in-situ vane shear strength was used in total stress analysis to determine the factor of safety at failure. Performance of the soft clay subsoil with regards to vertical and horizontal displacements, and piezometric response, when the failure was imminent is also described

Pile Embankment on Soft Clay: Comparison Between Model and Field Performance

The paper describes the performance of a full scale pile embankment on soft clay foundation which has been built and instrumented in Malaysia. Reference is made to a parallel design study carried out using centrifuge modelling technique

Incorporating Case Study and Site Visit for Teaching of Earth and Hydraulic Structures at Universiti Putra Malaysia

Case studies are widely used in civil engineering research but not in education and training. Case studies are important in the teaching of various subjects in the field of civil engineering. Site visits can also help to facilitate the students in recognizing and understanding the behaviour of structures and systems, especially when the students do not have any idea about them. The field of civil engineering covers a wide range of structures ranging from small to mega structures. Usually, small structures are seen regularly by the student and their behaviors are easy to comprehend. But mega structures such as dams are located far from the students and most of the students do not have any idea about their real configuration and their problems after and during construction. The Department of Civil Engineering, Universiti Putra Malaysia in applying the Outcome Based Education (OBE) addresses many programme objectives, one of which is life long learning. In the present study, the authors’ experiences in incorporating case study and site visits concerning earth dams in teaching two courses, namely Earth Structures and Hydraulics and Hydrology in order to address the life long learning objective is discussed. The feedback of the students on using case histories including data and site visits were analyzed and showed improvement in the student performance including their understanding on the materials covered in the lectures. Also, the students requested to continue such practices in teaching complex subjects in the field of civil engineering in order to enhance their interest and experience

Effects of Cyclic Test in Decreasing Damages to Structures and Roads on Gypsum Soils

Fine gypsum soils, when saturated and loaded, because of their high porosity, have large settlements. Compaction of the soil and removal of the load causes the soil to swell. These properties of gypsum soils cause many problems for structures built on them. For instance unsymmetrical settlement, uneven ground floor and cracks in façade are some of the problems. Likewise in road engineering, swelling of this type of soil located under the asphalt after absorbing water is one of it most important problem. So realizing and identifying the behavior of gypsum soils and effort in finding solutions for decreasing the amount of settlement and swelling are the main objectives of this study. The soil samples were from the City of Mashhad, which is the second largest city in Iran. These soils naturally contain high amount gypsum and hence have a special behavior. In this study, samples with different amount of gypsum were gathered and classified to seven sample groups. Preliminary tests done showed that the increase in the amount gypsum causes the soil plasticity index and unit weight to decrease, which in turn increases settlement. In order to investigate the influence of degree of compaction, all samples were compacted with different unit weight and the swelling potential and swelling pressures were measured after saturation. The results show that with increasing unit weight and amount of gypsum, the soil swelling potential increases. Cycles of wetting and drying and also cycles of loading and unloading were performed to investigate their influence on the gypsum soil

Assessment of Some Old Earth Dams in Malaysia Through Observation and Computer Simulation

In this study, two earth dams located in Malaysia were studied. The Labong Dam is a non-homogenous earth dam, whilst the Bukit Merah Dam is a homogenous earth dam. The performances of both dams against seepage were studied through the analyses of both observed and simulated phreatic surfaces. Simulations of seepage rate and phreatic surfaces through the dam were conducted by using SEEP/W model. The study showed that the SEEP/W model was able to predict (simulate) both the seepage rates and phreatic surfaces of the homogeneous and non-homogeneous earth dams with a reasonable accuracy. The Absolute Error (AE) between the predicted and observed seepage rates of both dams were found to be 0.03 m3/min to 0.18 m3/min. The average AE in the predicted phreatic surfaces for the maximum and minimum water levels in the reservoir were 0.6 m and 0.38 m for the non-homogeneous dam (Labong Dam), and 0.595 m and 0.75 m for the homogeneous dam (Bukit Merah Dam)

Application of Geophysical Techniques for 3D Geohazard Mapping to Delineate Cavities and Potential Sinkholes in the Northern Part of Kuala Lumpur, Malaysia

This work describes the application of the electrical resistivity (ER) method to delineating subsurface structures and cavities in Kuala Lumpur Limestone within the Batu Cave area of Selangor Darul Ehsan, Malaysia. In all, 17 ER profiles were measured by using a Wenner electrode configuration with 2 m spacing. The field survey was accompanied by laboratory work, which involves taking resistivity measurements of rock, soil, and water samples taken from the field to obtain the formation factor. The relationship between resistivity and the formation factor and porosity for all the samples was established. The porosity values were plotted and contoured. A 2-dimensional and 3-dimensional representation of the subsurface topography of the area was prepared through use of commercial computer software. The results show the presence of cavities and sinkholes in some parts of the study area. This work could help engineers and environmental managers by providing the information necessary to produce a sustainable management plan in order to prevent catastrophic collapses of structures and other related geohazard problems

Analysis of Longitudinal Cracks in Crest of Doroodzan Dam

Doroodzan earth dam is located in 85 km north western of Shiraz. Because of the unusual seepage flow in the left abutment, in 1992 an impermeable vane was grouted there. Soon after that, obvious changes in water Table profile occurred and simultaneously some incremental number of cracks in left abutment crest was appeared. In present study seepage through left abutment has been analyzed by considering water Table changes. Different phreatic surface line was carried out from recent 20 years in order to find the most vulnerable one. In addition, Seismic loading used to get proper perception of seismic stability. First, by gathering data from piezometric head through the left abutment, most critical phreatic line in left abutment section of dam was observed. Then by using present phreatic surface in numerical modeling of critical section in the left abutment of dam, long term stability of downstream in different situation were calculated. The conditions were changed by increasing the saturation zone and the time which saturation zone stay through the downstream body

Three point bending flexural strength of cement treated tropical marine soil reinforced by lime treated natural fiber

Marine soil in the Selangor State of Malaysia was characterized with respect to its engineering properties as pavement layer in road constructions. Samples were collected from North Klang area in Selangor, Malaysia and subjected to physico-chemical, mineralogical and geotechnical analyses. Quick lime or calcium oxide (CaO) treated coconut fibers were introduced to soil cement mixture to enhance the flexural strength of tropical marine soil. Three point bending tests were carried out on treated samples after 7, 14 and 28 days respectively. The tests results showed improvements in the flexural performance of the mixture as it could be seen by the increase in the flexural strength, Young’s modulus and the toughness index especially when the treated fibers were incorporated into the mixture. It was found that, the bond strength and interaction between treated fibers and soil was the dominant mechanism controlling the reinforcement benefit. It can be concluded that, the application of the CaO treated coconut fiber reinforced cement treated marine clay from Peninsular Malaysia is useful both in strength and ductility as pavement layer in road constructions