Ingenieur Vol.81 January-March 2020 | Page 30

INGENIEUR Figure 7. Author and his team carrying out inspection of Tunnel and Cross-Passage Adit as good as the input and coding. For example, taking results of analysis from a 3-D finite element analysis blindly and treating it as a black box could potentially be disastrous. Therefore, a good understanding of the fundamental mechanics at hand, coupled with in-depth knowledge on the analyses’ limitations is critical. Ultimately, the engineering tool or computer is not the engineer nor should it be substituted for sound engineering judgement. The usage of fundamental engineering principles helps engineers to develop their own analysis and design methodologies that suit local conditions and challenges at site. One example of an innovative design proposed by the author was used in the construction of the Maluri underground station of KVMRT SBK line. Tight regulatory requirements for rock blasting were extremely challenging given the close proximity of pre-existing and temporary steel and reinforced concrete structures. The innovative design developed by the author allowed blasting to be successfully carried with only a 1m blasting exclusion zone from the temporary king posts supporting a steel traffic decking. The innovative design was combined with an observational approach with vibration monitoring to verify the design, followed by detailed on-site inspection of the steel decking after each rock blasting to ensure that the integrity and safety of the structures were not compromised. This innovative approach expedited the construction progress with minimal traffic disruption and allowed completion on time. Figure 8 shows the steel decking in the MRT Maluri underground station during construction. Another example of innovative design is the use of a circular shaft in the irregular karstic limestone formation for the underground shaft excavation. The MRT Line 2 Intervention shaft 2 (IVS2) was the deepest, at a challenging depth of 57.5m below ground level. Harnessing the rock strength to support itself, shafts constructed in the rock were designed to be carried out without the need for temporary support structures. A combination of ground improvement via deep soil mixing/curtain grout and rock stabilisation methods allowed for 28 VOL 81 JANUARY-MARCH 2020