Qualitative Evaluation of Greenhouse Gas Emission Footprints from Surface Excavation

With growing concerns about global warming and greenhouse gas (GHG) emissions, there is an urgent need to evaluate and reduce the carbon footprint (CF) of surface excavation (SE). CF are GHG emissions caused by an activity or event. It is expressed in terms of the amount of carbon dioxide (COR2 R), or its equivalent of other emitted GHGs. Choosing an appropriate low-carbon emission method for SE is a vital task and involves environmental concerns due to several energy-consuming activities. Since essentially, every SE impacts the environment, it becomes very important to evaluate this impact and take necessary actions to minimize any negative consequence. The objective of this paper is to present a comprehensive overview on progress acquired over the years in understanding GHG emissions from SE and to discuss the steps in CF estimation. Publications were identified that reported GHG emissions and CF of SE over past 30 years. This literature review suggests that for most of the SE, the material production phase consumes a large amount of energy and is a major contributor of GHG emissions. Early phases of project planning should include appropriate ecological decisions consistent with the life-cycle assessment (LCA) and CF considerations. Pipe material and outside diameter should be considered during the SE to allow a detailed evaluation and reduction of their environmental impacts (EI). Incorporation of additional factors, such as cost and duration of the project into the environmental analysis is also recommended.

Structure and Costruction background of Ancient Tombs of Ulreung-do During Unified Silla Era

The tomb shape of the ancient tomb constructed in Ulreung-do and the burial structure are analyzed and the construction period is established through the burial items and the system and background are reviewed. As a result of the review, the ancient tombs of Ulreung-do that had the burial structure constructed on the stone structure with the red stones and they were the most appropriate burial facilities for the natural environment of Ulreung-do with its geology, topography, climate or the likes. Originally, the ancient tombs of Ulreung-do had known its burial structure as the stone chamber tomb with horizontal entrance, but as a result of structure analysis, they were confirmed to be the corridor-style stone chamber tomb. Those reported ancient tombs of Ulreung-do from ground surface, excavation survey and others are confirmed by the characteristics of earthenware excavated as the burial items with the construction period to be late 8th century to 9th century. In the main land region of the unified Silla era, had a number of cases grouped in Ulreung-do for the disappearing corridor-style stone chamber tomb that it is confirmed to have similar shapes with the capital city of the similar period. Those earthenwares decorated splendidly with the stamped design pottery excavated from the living relics and ancient tombs of Ulreung-do were produced and consumed in the capital city. The structure of the ancient tomb is in the corridor-style stone chamber tomb and the earthenware carried in for significant number from the capital city and based on such facts, the ancient tombs of Ulreung-do could be presumed as highly likely to be constructed by the migration of those people in the capital city of Silla Dynasty.

EXCAVATION ASSESSMENT IN WET TROPICALLY SEDIMENTARY ROCK

The selection of suitable methods to be employed for surface excavation works is particularly important in geotechnical engineering projects. Factors such as environmental constrains, rock properties and size of site may affect the selection of machine required for surface excavation. Wrong selection of equipment and technique can result in unrecoverable expenses and thus, should be avoided. Great challenges in excavation works are expected in sedimentary rock where the occurrence of discontinuity such as bedding thickness, foliation and the inhomogeneity of rock as well as effect of moisture can greatly affect its excavatability. This paper aims to identify and highlight the factors affecting the excavation works in wet tropically weathered sedimentary area as what have been experienced in Malaysia. Some of these factors, however, are not specified in the existing general excavatability assessments. Assessment by practical excavation was carried out at three sedimentary rock sites in Nusajaya, Malaysia, taking into account the related parameters. Statistical analysis by using SPSS was then being conducted in order to determine the correlation of each parameter with productivity of excavation and their significance in affecting the excavatability.Based on the results obtained, it was found that the parameters such as Is50, R, UCS, density, ITS, Js, JL, Jd, IP and moisture content play significant roles in affecting the excavatability of sedimentary rocks. Meanwhile, the existence of bedding, Id2 and Jn are deemed to be neglected. It is believed that this study can help to enhance the knowledge on factors that complicate the excavation works in sedimentary areas.