3-D Modeling of Liquefaction Phenomenon Using Distinct Element Method

Liquefaction is one of the most important, complex and controversial topics in geotechnical earthquake engineering. Since Niigata earthquake in 1964, it has been popularly recognized that the liquefaction induced ground failures cause severe damage to the built environment. To take measures against such damage, understanding the mechanism of liquefaction and its associated phenomena from macroscopic and microscopic viewpoints is very important. There are two approaches, which are experimental and numerical ones, to study them. Although discussion from the macroscopic viewpoints can be done by experiments, it is not so easy to perform experiment to obtain microscopic information on liquefaction and its associated phenomena. Among the numerical tools available at present, Distinct Element Method (DEM) is an effective method that can simulate the mechanism of liquefaction at microscopic level. We have developed a new 3-D DEM model with a simple algorithm by which the effect of pore water and its behavior can be directly considered to improve the mechanical behavior of the particles. Conventionally, these effects were not considered in the field of DEM. Our primary objective in this paper is to simulate the hollow cylindrical torsion test, which replicates the ground condition before and during the earthquake, under undrained and cyclic loading conditions using the proposed model

Non-Linear Modeling of Dip-Slip Faults Using Applied Element Method

On observing the recent big earthquakes that have occurred in Turkey (M.7.4, 1999.8.17) and Taiwan (M.7.3, 1999.9.21), it is understood that the differential ground displacement is also responsible for the failure of structures. Now, it is understood that there is a need to channelize the research interests to study the failure propagating mechanism through the soil deposit. Numerous researchers have attempted to study this phenomenon through, experiments for understanding the effects of seismic fault mechanism and soil deposit parameters on surface deformation characteristics. However, from the widespread damage caused by the recent events, it is now clear that the earthquakes in different geological regions show drastic variations in their effects such as, large surface upliftment/displacements of unconsolidated soil deposits, lying commonly over the active and potentially active faults. Hence, there is a need to develop a numerical model which can give quantitative results to establish a relationship among characteristics of seismic fault rupture, soil parameters and location and area of affected zone. For this reason, we attempted to develop a new application of Applied Element Method (AEM) to study the fault rupture zone

Comparative study of planning history, spatial development and sociological significance of the back alley in Yangon and Singapore

A comparison of two similar types of back alley spaces: Back Drainage Space (BDS) in Yangon and Back-lane in Singapore, is conducted to find out if there are any relationships between their spatial development and lessons that can be learned from the precedent case in Singapore. Commonalities and differences of the back alley are identified by comparing the historical urban context of their formation and development in British colonial cities. The findings suggest that the back alley spaces in both cities, despite divergent circumstances and development after independence, possess common traits as interstitial space between public and private, with a unique way of spatial management based on informal, mutual agreement, which suggests some useful ideas when considering the role of these spaces in the redevelopment of Yangon in the near future

Numerical Study of Collapse Behavior of RC Structure due to Unexpected Extremely High Seismic Loads

特集 都市基盤の安全とICUSの活

Fundamental Study on Failure Behavior of Pile Foundation using Applied Element Method

特集 都市基盤の安全とICUSの活

Numerical Study on Behavior of Crowd of People for Evaluation of Safety and Security of Urban Facilities

特集 都市基盤の安全とICUSの活

Use of Change of Electric Power Supply for Evaluation of Earthquake Damage

特集2 耐震構造学研究グループ (ERS

Fundamental Study on Land Value Evaluation Considering Seismic Risk

特集 都市基盤の安全とICUSの活

Characteristics of Adobe Structure Damage observed in Iran-Bam Earthquake (Dec. 26, 2003)

特集2 耐震構造学研究グループ (ERS