Analytical study of the causes of the major landslide of Bukit Antarabangsa in 2008 using fault tree analysis

Innov. Infrastruct. Solut. (2017) 2:55 DOI 10.1007/s41062-017-0105-4 TECHNICAL PAPER Analytical study of the causes of the major landslide of Bukit Antarabangsa in 2008 using fault tree analysis Danish Kazmi1 · Sadaf Qasim1 · I. S. H. Harahap2 · Thu Hang Vu3 Received: 26 July 2017 / Accepted: 25 September 2017 / Published online: 10 October 2017 © Springer International Publishing AG 2017 Abstract Previous researchers have observed that imprecise design, flawed construction and non-maintenance of slopes are major contributors to Malaysian landslides. The prominent landslide of Bukit Antarabangsa in 2008 once again alarmed the Malaysian construction industry and prompted a review of their practices and standards. This study investigates the causes of the Bukit Antarabangsa landslide by analyzing a pipe burst event, which according to previous studies triggered the landslide. The technique of fault tree analysis (FTA) is applied to trace factors contributing to the pipe burst. The events and their subjective probability for the FTA have been ascertained by experts in the Malaysian construction industry through survey research using a snowball sampling technique. Subjective probability derived for FTA indicates that high acidity levels in the water, improper design and a temporary extra surcharge load were more likely to be causal factors than other potential triggers. The events that are found to have the highest subjective probability in causing the pipe burst correlate with * Danish Kazmi Sadaf Qasim I. S. H. Harahap Thu Hang Vu 1 Department of Civil Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan 2 Department of Civil and Environmental Engineering, Universiti Teknologi Petronas, 32610 Perak, Malaysia 3 School of Engineering, Edith Cowan University, Joondalup 6027, Australia human errors which occur either as a result of negligence or as a result of several types of uncertainties. In this context, this study suggests a theoretical framework to address human errors and to mitigate the chances of slope failure. Keywords Bukit Antarabangsa · Pipe burst event · Fault tree analysis · Snowball sampling · Human errors · Slope failure Introduction Landslides are one of the major geohazards occurring frequently in Malaysia. They are responsible for both compensatory and non-compensatory losses. Besides damaging infrastructure, they cause loss of life, environmental degradation, and interrupt the economic activity. In Bukit Antarabangsa in 2008, a landslide damaged the settlements and resulted in casualties [1]. Altogether this landslide caused five casualties, buried fourteen bungalows, and forced approximately 2000 residents to evacuate their homes [2]. In most landslide studies, the primary focus is toward the technical perspectives of failure, and human errors are neglected. Authorities have already established that no signs of earth motion were evident in seismic records, so the possibility that the 2008 landslide was triggered by earthquake forces is negligible. Another possibility which has been highlighted is that this landslide was the outcome of a pipe burst [3]. The official authority of Majlis Perbandaran Ampang Jaya (MPAJ) at Ulu Klang, Malaysia reported on the 2008 Bukit Antarabangsa landslide, identifying leaking water pipelines near Jalan Wangsa 11, which is very close to the landslide area, being responsible for the buildup of water pressure in the soil pores. Harahap and Aini [4] observed that the landslide took place after 20 years of 13 Vol.:(0123456789) 55 Page 2 of 11 Innov. Infrastruct. Solut. (2017) 2:55 project development, and it is thought to have been the result of a water pipe burst on the hill. This study aims to identify the causes of the pipe burst event which potentially led to the slope failure and the subsequent landslide in Bukit Antarabangsa. If this landslide was attributed only to technical causes, then this is not the complete picture, because the previous record of Malaysian landslides proves that human-generated design and construction errors play a significant role in these types of events. The issues related to improper drainage in the slope and a lack of adequate maintenance are fairly common and human errors must be analyzed alongside technical causes to comprehensively evaluate this landslide event. In principle, there are many factors that may stimulate pipe failure including environmental and external conditions (soil moisture and air temperature), structural and physical variables (pipe length, pipe diameter and material), internal factors (water quality and water temperature) and maintenance variables (number of leakages, number of repairs and number of failures). The aging of pipes also contributes to failure as it affects the material properties and obstructs the water flow. Røstum [5] indicated that nearby excavation around the bedding area of the pipes is another triggering factor, as it disturbs the layout of the pipe. A list of important factors affecting the quality of the pipe is given in Table 1. Literature review See-Sew and Tan [6] investigated the causes of landslides in Malaysia over a period of 6 years and reported that 43 out of a total 49 landslide cases were the result of design and construction errors. Jabatan Kerja Raya (JKR), which is a federal government department in Malaysia, also confirmed that most of the landslides in Malaysia are primarily caused by design and construction errors, as shown in Fig. 1. Some of the common flaws leading to slope failure are as follows: Table 1  Factors affecting water pipes [5] 13 Fig. 1  Landslides statistics of Malaysia [7] 1. abuse of prescriptive methods in terms of gradient 1H:1V, 2. increasing the number of berms without considering the effects on slope safety factors, 3. insufficient laboratory test results, 4. lack of adequate drainage facility. Proactive approaches are often used to analyze the uncertainties associated with slopes. For example, probabilistic reliability assessment (PRA), which relies on uncertainties related to inherent factors, is used to estimate the likelihood of failure. In addition to PRA, there are other established approaches that are used to determine safety factors, load factors and resistance factors. Peck [8] proposed an observational method to deal with uncertainties, but the feasibility of this method is limited to situations where design can be altered and performed over conservative values of load and material properties, which may not be suitable for all geotechnical structures. During the past few years, attention has been diverted toward reliability analysis as a way to deal effectively with uncertainties. Nadim [9] discussed two basic categories of uncertainties: Structural variables Environmental variables Internal variables Maintenance variables Location Diameter Length Year of construction Wall thickness Laying depth Pipe material Internal protection External (...truncated)