Landslide monitoring using global positioning system and inclinometer techniques

Abstract

Landslide is one of the prominent geo-hazards that continuously affect many tropical countries including Malaysia, especially during the monsoon seasons. For the past 25 years, landslides have occurred throughout the country that caused property destruction and loss of life, especially near the hillside areas. A landslide monitoring scheme is therefore very crucial and should be carried out continuously. Various studies have been conducted to monitor landslide activities such as conventional geotechnical and geodetic techniques. Each of these techniques has its own advantages and limitations. Therefore, this study focuses on the effectiveness of the combination approach of GPS technology and inclinometer techniques for landslide monitoring. The study area is located at residential area Section 5, Wangsa Maju, Kuala Lumpur, Malaysia. In the first stage, the geotechnical data have been collected using Mackintosh probe whereby the laboratory test on disturbed soil sample has been carried out to identify the composition of the soil structures. Next, the probe test was also conducted to determine the soil layer and soil contents at the study area. The inclinometer instrument has been placed at five (5) selected monitoring points and nine (9) epochs of inclinometer measurements were made. At the same time, the GPS observations have also been carried out for nine (9) epochs separately using four (4) GPS techniques such as static, rapid static, single base Real Time Kinematic (RTK) and RTK network. This GPS network consists of four (4) control points and eleven (11) monitoring points. The GPS observations data were validated, processed and adjusted using four (4) adjustment software namely Trimble Geometry Operations (TGO) software, Topcon Tools, STARNET and GPS Constraint Program. Next, GPSAD2000 and Static Deformation programmes were used to analyse the displacement of the monitoring points. The results have shown that the GPS technique can be implemented with inclinometer technique to detect horizontal displacements up to ± 40 mm and vertical displacements less than ± 80 mm,