NATURE OF PROJECT: GEOLOGICAL & GEOHAZARDS ASSESSMENT
CLIENT: PROJEK LINTASAN SG BESI – ULU KELANG SDN BHD
DURATION: DEC 2017 – MAR 2018
INTRODUCTION
SUKE is a 24.4km, three-lane, dual-carriageway, elevated expressway running from Sri Petaling to Ulu Kelang. It has 14 interchanges and reaches out to over 60 residential areas as well as connects to major highways and roads in Kuala Lumpur. There is a need to produce a comprehensive geodatabase information such as geomorphology, geological terrain, engineering geology and any other geological information that can be compiled and updated for which project owner can rely on as a guide for this highway construction projects. The highway alignment is very close to existing residential area of Taman Saga which is very vulnerable to geohazards triggered by these constructions.
Boulder mapping and resistivity survey were conducted in this area to assess any potential geohazards either rockfalls, boulder falls and landslides. Six (6) criteria were considered during boulder mapping which are; i) Boulder location, ii) Embedded depth, iii) Boulder shape, iv) Boulder size, v) Local slope angle and vi) Vegetation density. Six (6) resistivity survey lines were established at project site to identify subsurface profile of the slope.
RESULTS
Boulder Mapping
There are two (2) areas of boulders accumulation in project site which are; i) Boulders on the slope face near to Taman Saga: which have potential of boulders fall as its located on the slope steeper than 35°. There also evidences of boulders fall during construction due to excavation works. ii) Boulders located along the stream channels in the forest reserved which prone to debris flow hazards.
Figure 1: Distribution of boulders on the slope face and along stream channel
Resistivity Survey
Resistivity survey shows that the subsurface profile consists of; i) bedrocks/boulders on the upper part of the slope, ii) scattered boulders on the middle part of the slope and iii) weak materials of medium dense to dense soils layers on the slope toe.
It is interpreted that the heavy load of boulders is supported by weak materials of soil which are prone to landslides hazard in this area. Boulders are surrounded by insitu soil.
Figure 2: Geological subsurface profile interpreted from resistivity survey
CONCLUSION
The project site prone to potential geohazards; landslides, debris flow and boulders fall. Advice was given to the project owner to mitigate/solve this potential problems.
