External Projects 
Project ID: I3C123E1
Customization of Decision Aid for Tunnelling (DAT) Software for Construction Risk Assessment Studies for the Underground Science City (USC) at Kent Ridge and Underground Warehousing & Logistics Facility (UWLF) at Tanjong Kling/Jurong Hill
Principal Investigator: Robert Tiong (Assoc Prof)
JTC Co-Principal Investigator: Ng Kian Wee
Status: On- Going
Abstract:
Underground facilities have been widely used for urban transportation (e.g. subway and MRT) and storage facilities for oil, chemicals, etc. over the world, because they result in land savings and offer benefits of enhanced safety and security. Due to limited land available in Singapore, underground facilities shown high potential values. Since the construction of underground facilities is costly and it exposes to various types risks throughout the development, risks must be identified, assessed and managed.

In order to manage risks associated with underground facilities construction, risks will be identified according to phases of project life-cycle. The identification of risk will be carried out through reviewing existing literatures, interviewing experts, and studying actual projects. Then, they are assessed quantitatively, qualitatively or the combination of both, particularly using computer simulation on the impact of risk factors. These risk analysis will lead to a higher confidence in the estimation of construction duration, project investment cost and contingency budget required. Based on the results of risk assessment, risk management strategies will be suggested. These research findings will thus enhance the project’s constructability and viability and will bring about a higher level of certainty in the successful implementation of the project.
Project ID: I3C131E2
Pilot field trial on application of soft materials for reclamation fill using menard vacuum consolidation
Principal Investigator: Tan Soon Keat (Assoc Prof) and Chu Jian (Assoc Prof)
JTC Co-Principal Investigator: Lam Kok Pang
Status: On- Going
Abstract:
Land reclamation in Singapore now meets severe shortage of sand and gravel as filling materials. On the other hand, the disposal of soft cohesive soil (SCS) generated through infrastructure development and maintenance dredging works becomes a problem in the land-scarce Singapore Island. These two problems can be overcome if an innovative method can be developed to use these abundant soft materials to replace the acute shortage of granular fill material for land reclamation works.

However, when these soft materials are used as reclamation fill, soil improvement is required. Because of stability issue, the effectiveness of conventional methods of soil improvement such as using vertical drains with fill surcharge is limited. Meanwhile, the Menard Vacuum Consolidation (MVC) method is a proprietary system which was developed for preloading and consolidating soft and very soft saturated fine grain soils. The procedure consists of installing vertical and horizontal vacuum transmission pipes under an airtight impervious membrane producing an atmospheric pressure on the soil. This project is intended to adopt MVC system for the treatment of soft cohesive soil as a fill material in the land reclamation of Singapore.
Project ID: I3C131E3
Post-mortem Assessment of Beaudrain-S Site Trial
Principal Investigator: Chu Jian (Assoc Prof)
JTC Co-Principal Investigator: Lam Kok Pang
Status: On- Going
Abstract:
Beaudrain-S system is a vacuum consolidation technique that is used for the compression and strengthening of soft clay material. In Beaudrain-S system, a vacuum pressure is applied to the pore void of soil so that pore water can be drained out and soil can be compressed. Compared with the other vacuum consolidation technique Menard Geo-system, PVD in Beaudrain-S system is connected directly to the tubing system instead of using a membrane-covered sand layer to transfer the vacuum loading.

From Aug 2010 to May 2011, a site trial of Beaudrain-S system in a 50m×100m area was conducted in Tuas of Singapore. The geological strata consisted of sandy clay fill, marine clay, and residual soil from top to bottom. The depth of each layer was very uneven throughout the site. The site was instrumented with various types of transducers and detailed soil investigations were carried out before and after the ground improvement.

In order to evaluate the quality of soil treatment and the post-construction field performance, a post-mortem assessment should be carried out. Besides, the field instrumentations are untouched after the soil improvement which can be made use of to reduce the cost of the experimental work. Field data, such as post-construction settlement, pore pressure re-distribution, strength enhancement/reduction, and field deformation, will be valuable information for evaluating the effect of Beaudrain-S system.
 
Project ID: I3C132E4
DC Renewable Connected Building Grid for Wireless intelligent LED Lighting system (WiLLs)
Principal Investigator: Dr Tan Yen Kheng
JTC Co-Principal Investigator: Jason Foo and Rao Yimin
Status: On- Going
Abstract:

Built environment and city management are identified as one of the main focus areas of Singapore sustainable blueprint. Many opportunities exist to save excessive wastage of electricity in building environment. Given today’s typical building AC power distribution infrastructure, there is not much choice; large wave of DC renewables like the upcoming SolarNova programme to be widespread in Singapore. To overcome the drawbacks of using the conventional DC-AC/AC-DC power conversion approach, a direct low voltage (LV) type of DC building grid emerges. The LV DC grid is a more efficient way to provide DC power for the electrical LED lighting system and all digital devices used in the buildings like computers, printers, cell phone chargers and assorted other personal use devices, as well as basic building controls, sensors, HVAC actuators, security systems and A/V systems – they are DC in nature.

In this project, the objectives are (1) to conduct a feasibility study on fully DC powered building, (2) to develop strategies to harmonize with the AC world and (3) opportunity for implementing the study and proposed strategy in the ongoing testbed in Clean Tech One (CTO). The project aims at developing an energy efficient low voltage DC grid to power a smart LED lighting system as well as digital devices so as to reduce the building electricity used while maintaining the quality of light and human comfort thru smart ICT technology. We want to achieve 20% energy savings by having an energy efficient DC grid transmission and distribution. With state-of-the-art driverless LED luminaires, we aim at reaching 50% energy savings. Wireless lighting controls will add 30% more of energy savings. All this is done while ensuring user safety and automated personal control. In our demo, we want to present the work done in DC powering a typical personal space in an office setting. We have employed a 380V DC source to emulate the solar panels and fuel cells. This is then stepped down in single conversion stages to obtain low voltages of 5V, 18V and 24V which then directly power our appliances without the need for bulky drivers and adapters. Currently, we are developing converters to give multiple DC output voltages with just one power stage conversion. Through this work, we want to demonstrate the feasibility of LVDC powered systems as a standard for buildings.