Contract of Simpang Pulai-Lojing Highway was commenced in 1997. Since then, the unstable hillside at a site at CH23+800 in the north-western Cameron Highlands Malaysia was cut to ridge top but instability still observed. The cutting was mainly in schist and was about 250m high. In August – September 2003, a landslide about 190m high and between 200m and 430m wide was formed at the site as the hillside was cut into for roadworks. The work reported here shows that the overall velocity of movement of the displaced mass of the landslide is declining slightly year on year and the head of landslide had moved more than 30m by August 2010 since September 2003. In 2010 the top of the main body of the landslide was moving at about 0.5m per year. Points on the landslide continue to move 2005-2010 in generally the same direction as 2003-2005. The writer was provided with survey data at the landslide and adjoining area obtained in 2003, 2005 and 2010 by different methodologies. The survey in 2003 was a composite as-built survey; 2005 was an aerial survey and 2010 was a LiDAR survey. The 2010 LiDAR data has been used as a basis to give both the 2003 as-built survey plan and 2005 orthophoto a common horizontal reference frame. Both the 2003 as-built survey plan and 2005 orthophoto have been adjusted to fit the 2010 LiDAR data, which is expressed in terms of old MRSO grid coordinates system after transformation. The adjustments are affine transformation (2003 and 2005). The 2010 LiDAR data has been reduced to the vertical datum used in both 2003 as-built survey and 2005 aerial survey. A number of recognisable points within the landslide have been identified in all three surveys. The differences in coordinates of the points on the dates of the three surveys provide two sets of movement vectors (2003-5 and 2005-10). There are 150 such vectors. Thirty-three check points have been identified in the 3 surveys outside and adjacent to the landslide at places where movements are not expected. The apparent movement of these points is an indication of the uncertainty in the displacement data. Total displacements of 12 total station survey markers within the landslide have been plotted with time. Ground points very close to these markers are plotted for comparison. The latter are greater than the former by about two metres suggesting that the landslide had started moving before the start of deformation monitoring. / published_or_final_version / Applied Geosciences / Master / Master of Science

A study of photographs of the Pos Selim Landslide has been carried out to determine the geometry and movement of the Northern Earthflow, to delineate the Northern Flank and the Northern Toe of the surface of rupture of the landslide and to study deterioration in the Southern Toe Buttress. All the available stereo-pair photographs of the northern part and toe zone of the landslide were studied under the stereoscope. Site history, site record photographs were also studied. Key evidence was obtained of continuing movement of the landslide to 2010. The Northern Earthflow was found to be moving with and not over the main landslide from October 2003 to 2010 (to the resolution of the photography). The Northern Flank of the landslide and Northern Toe of the surface of rupture of the landslide were delineated by reference to a newly-recognised Northern Deformation Area. The observations made are recorded by updating the file Geomorphology_ September_20052D , updated by Choi (2010). / published_or_final_version / Applied Geosciences / Master / Master of Science

The objectives of the study were 1) to carry out sensitivity analysis to determine the effects of different mesh geometries on the calculated surface strain field of the Pos Selim landslide; 2) to examine the strain field 2003-5 using the best mesh; 3) to examine the velocity profiles 2005-10 as compared to 2003-5; and 4) to draw conclusions about landslide mechanics. The original data used by Wong 2010 was adopted for fulfilling objectives 1 and 2. The corrected vector data by Lam 2012 was adopted for fulfilling objective 3. The main analysis method was done by the calculation by the Excel and was presented in graph by either Excel or Surfer 6.0. Contours are constructed by hand rather than computer for greater reliability. The strain fields for different meshes are broadly similar. The velocity data 2003 – 2010 has been interpreted in relation to the suggestion of Puzrin & Schmid 2011 that any compression zone at the toe will be reflected in a bi-modal velocity profile. The velocity profiles are not bi-modal, suggesting no compression zone exists at the toe. This supports the field evidence, which suggests that failure had already occurred in 2003, in the sense that a rupture surface had fully formed from head to toe. A Fault-Articulation Hypothesis has been tested using the rupture surface profiles suggested by Wu 2009. This hypothesis is “the landslide exploits existing faults and makes new ones where needed to assist articulation”. Evidence supporting the Fault-Articulation Hypothesis was found. It was found that Faults B and C were exploited for turning between different segments at South and Central Sections, where new faults T1, T2 and T3 were formed for turning in Head Graben. At North Section Fault B appears to have been exploited for turning between the Main Body and Head Graben but neither a geological nor a new fault appears to exist between the Main Body and the Toe Buttress. The velocity profiles 2003 – 5 and 2005 – 10 were compared. It is evident that the landslide decelerated significantly during this period. / published_or_final_version / Applied Geosciences / Master / Master of Science

published_or_final_version / Applied Geosciences / Master / Master of Science

published_or_final_version / abstract / Applied Geosciences / Master / Master of Science