A Brief Overview of the Development of a Landslide Prediction and Management System for the East-West Highway, Malaysia

This paper presents a brief overview of the development of a landslide prediction and slope management system for the East- West Highway in northern Peninsular Malaysia. The collection and effective utilisation of large amounts of data is discussed along with the development of landslide hazard and risk ratings for over 1,000 embankments and cuttings along the highway.

Introduction

The East-West Highway is located in the northern states of peninsular Malaysia and forms the only significant transport link between the east and west coasts in the northern section of the country. The highway is 112.6 km long and was opened in 1982 after a construction period of twelve years. The highway traverses the rugged Main Range mountains which, in the past, have formed a barrier to cross peninsular communications and commerce. Even prior to opening, the highway had been affected by large landslides. This instability has continued with some landslides requiring road closures of up to a week. Fatalities due to landslides have occurred. Between 1982 and 1995 approximately 521 million Ringgit (roughly 250 million AUD at 1995 exchange rates) had been spent specifically on landslide remedial works on the highway. There are several contributing factors that have lead to the development of widespread slope instability on the highway. These include:

• the rugged nature of the terrain (steepness, dense primary jungle);
• high rainfall;
• deep residual soil profiles; and
• an active communist insurgency during construction. Guerrilla activities resulted in the adoption of high embankments and steep cuts to avoid the sabotage of tunnels and bridges. The unrest also put a premium on speed and resulted in minimal forward planning i.e. selection of the best corridor. In addition construction was under armed guard and the surrounding jungle was mined.

In an effort to reduce its long term expenditure on landslide remediation, the Government of Malaysia commissioned the “East-West Highway Long Term Preventive Measures and Stability Study” to provide a rational basis for the allocation of funds for landslide prevention, remediation and slope maintenance works along the highway. The team for this project was comprised of the Government of Malaysia, Perunding Zaaba (Malaysia), Soil and Rock Engineering (Malaysia), the University of Bristol and the University of Strathclyde.

The three year study was completed in September 1996 and resulted in delivery to the Malaysian Public Works Department of a prioritised listing of the risk of landsliding for all the slopes (1,123 slopes comprising 464 cuts, 577 embankments and 82 natural slopes) along the highway. This risk rating was then used to prioritise landslide prevention works. In addition a computerised database with a facility to allow updating of the conditions and the risk rating at each slope was handed over to Public Works Department.