Modern Rockfall Solution Meets Ancient Cave in Perak, Malaysia
Gua Tempurung is a recreational cave located in the state of Perak. It was first discovered in 1887 and the Department of Minerals and Geosciences estimated the age of the lime rock formations in the cave to be about 250 and 400 million years old. During the height of the World War II, many locals sought refuge in the cave from the invading Japanese. The cave was open to the public in 1997 as a recreational site, and has become a famous eco-tourism destination since then.
In December 2015, the cave was closed to the public because cracks were discovered in a certain area. This portion is not too far from the entrance and there is a stair way leading tourists deeper into the cave. It is highly foot-trafficked and therefore it was closed for the period when rectification works are being carried out.
A survey was done using the TLS (Terrestial Laser Scanning) because the condition of the cave restricted the conventional survey methods. It was found that the rock slope is experiencing ‘planar failure’ and was classified as critical. It stands at an 80° angle slope; cracks opening at 1 to 3 cm width are visible on this weak structure. The consultant proposed a solution using active rock netting with rock bolting to solve this problem.
Being a reputable technical reference in rockfall solution, the consultant approached Maccaferri for our input to their problem. The affected area is 20-meter width x 12-meter high and a failure will potentially drop 28 ton of weight. Maccaferri proposed a combination of HEA Panel and double twist rockfall protection netting to secure the area. Works carried out were recquired to use equipment of low vibration and noise, so not to disturb the condition of the cave. Due to tight space and limited access, construction was challenging but nonetheless it was completed within a month.
The cave was open to the public again recently, in April 2016.