NATURE OF PROJECT: GEOLOGICAL & GEOHAZARDS ASSESSMENT
CLIENT: PROJEK LINTASAN SUNGAI 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. SUKE will serve as a viable alternative to MRR2 highway by minimizing traffic congestion in Cheras, Pandan Indah, and Ampang, as a direct link for a new greater growth city such as Kajang, Segambut, and Kepong and as an effective and high capacity traffic dispersal scheme for eastern Klang Valley areas. At package CB1 (B7 & B8), the proposed highway alignment is in close distance with the residential houses of Taman Saga. Boulder fall hazard is one of the geological problems encountered at this location.
Figure 1: The highway alignment in close distance with residential houses.
BOULDER MAPPING
Boulder mapping was conducted on hilly terrain with several streams flow down the slope towards depression areas close to Taman Saga. The boulder mapping was conducted to map the location and condition of the boulders and recommend suitable remedial type. The mapping methodology was adopted from the suggestion of Au and Chan (1991) and engineering judgment based on available records. Besides, the field observation is important to study the hazard posed by the boulders. Six (6) criteria were considered for this boulder mapping which are; i) Boulder location, ii) Embedded depth, iii) Boulder shape, iv) Boulder size, v) Local slope angle, and vi) Vegetation density.
RESULTS
There are two (2) areas of boulders accumulation exist in the project site which are; i) The boulders on the slope face near to Taman Saga: which have the potential of boulders fall as its located on the slope steeper than 35°. In fact, there also incidents of boulders fall during construction due to excavation works. ii) The boulders located along the stream channels in the forest reserve which prone to debris flow hazards.
Figure 2: Distribution of boulders on the slope face and along stream channel
RECOMMENDATIONS
Conceptual recommendations were suggested at this particular area such as stabilization/scaling (boulders on a slope) and installation of flexible protection net (boulders along the streams) to mitigate this issue as shown in Figure 3. Hence, the boulder mapping execution is very crucial at any locations that face the same problems with Taman Saga, especially on granitic rocks area.
Figure 3: Suggested recommendations for the boulders hazard
