A preliminary study of the economic dimension of underground rock caverns for water storage in Singapore : a numerical analysis

• Main Author: Chua, Zheng Xian
• Other Authors: Zhao Zhiye
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Civil engineering::Geotechnical
• Online Access: http://hdl.handle.net/10356/75691
• Institution: Nanyang Technological University

Due to the scarce land resources in Singapore, increasing the water storage capacities in the underground by rock caverns is urgent to meet increasing demand of water to secure a sustainable development. In this report, a preliminary study on the effects of cavern span, height, radius, shape and dimension on the cavern stability was presented. The objective of this report is to evaluate and analyze the economic way to build an underground rock cavern to provide guidelines and design methodology for the first underground water storage cavern in Singapore. A finite element software called ROCSCIENCE Phase2 was adopted in this study. Worst condition of Bukit Timah Granite was considered in the numerical analysis to provide conservative results. Based on this study, it is suggested that the radius of caverns should be around half of the span width (i.e., B/R=2) to reduce the displacement. The smaller the depth of rock cover, the smaller the cavern displacement. The minimum rock cover thickness should be at least the same as the cavern span to eliminate the excessive yielded element. Shape of the cavern is largely affected by the insitu stress ratio. A guidance for selection of the cavern shape was provided in the report. Furthermore, cavern dimension (B/H) is suggested to match with the insitu stress ratio (K ratio) to have the best stress distribution. In addition, rock support system was introduced to enhance the stability of the caverns. A guidance was given on the selection of rock support system for caverns constructed in Bukit Timah Granite