Browsing by Author "Perera, HDH"

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item: Conference-Full-text
Effects of discontinuous properties on the stability of tunnels
(Department of Earth Resources Engineering, 2010-09) Nawarathna, THK; Kulathilake, LKNS; Perera, HDH; Premalal, PAM; Dharmaratne, PGR; Chaminda, SP; Rohitha, LPS; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, S
Many failures of underground openings during excavation are closely related to discontinuous properties of the surrounding rock mass and they affect differently to the stability of underground openings. In this research, attempts have been made to study the effect of discontinuities over the rock mass stability with various infilling materials, dip angles and strikes by using laboratory scaled models. Specimens were casted using cement concrete mixture and five different dip angles (30°, 45°, 60°, 75°, 90°) and three infilling materials (quarry dust, kaolin and graphite) have been selected for the study. Models were tested to determine their uni-axial compressive strength. The results indicate that the dip angle of the joints and the orientations of the tunnel axis have significant impacts on the stability of the tunnel. The dip angle at 90°, perpendicular to the tunnel axis shows a higher stability while the angle at 45°, shows the lowest stability. The tunnels excavated with axis parallel to the discontinuous plane should be avoided as much as possible. If it is unavoidable in any circumstances, well designed support system should be used. Types of infilling materials also affect the stability of the tunnel with graphite being the most unfavourable among the selected materials.
item: Thesis-Abstract
Vehicle yard control system (VYCS) for the Sri Lanka ports authority
Perera, HDH; Premarathne, S
The aim of this project is to develop an on-line vehicle yard controlling system that provides customers with the facility to check there vehicle arrivals, vehicle parking vehicle delivery and vehicle status online through web and short message service(SMS). System will provide all the vehicle movement information, tracking and the updated status of the vehicle. The current manual system puts the customer into great inconvenience specially by the requirements of his physical presence in the SLPA premises to find out the vehicle information, status and the yard location etc. The search for a more convenient operational process is envisage in order to make the customer’s task easier an acceptable. The widely used mobile phone and its short message service is made use of in order to achieve our desired goal. Therefore It is one of the important operational areas, which is highly required to improve the quality of service level. The new system will immensely contribute towards the total productivity of the yard, if the system is streamlined and computerized in a proper manner. Computerization of this area will eliminate drawbacks of the current manual system. Further, it enhances customer satisfaction through improved service. Due to space limitations in the area allocated for imported vehicles, it is necessary to design a proper yard layout. Each area is marked in the means of drawing lines, numbering them to reach the best utilization of ground space. The system will also endow with a Web interface for the Clearing Agents who could inquire about their vehicles. Further the system generates SMS to confirm the parking location, transferring and the delivery of the vehicles. System also provide forecasted information regarding vessel arrivals, discharging, loading etc. When compared with the existing system, the new system offers huge advantages for the customers. The system is simple, secure, convenient, economical, faster and technologically up-to-date. Its ability to send SMSs to a customer any time a change occurs to his or her records in the system is one of its strikingly value adding features. This cutting edge not only benefits the customers but also helps the organization establish a close rapport with them. The new system will enable automation of the entire functions of the vehicle handling, thus conceiving an efficient, convenient, reliable, speedy and cost-effective operational model for the SLPA.