Prediction of Settlements of Soft Clay Caused by Earthquakes

This paper develops an analytical method for the calculation of the earthquake-induced settlement of foundation by using Biot\u27s type consolidation equation. In order to investigate the effectiveness of the proposed method, a comparison of the numerical result with the observed earthquake-induced settlement on the site at Sendai in Japan caused by the miyagioki earthquake in 1987 will be presented

Settlements of Breakwater on Soft Seabed Ground under Ocean Waves

A procedure for predicting the wave induced excess pore water pressure and residual strain of clay using the results of cyclic triaxial tests on the reconstituted Ariake clay is described. Thereafter, the results of a numerical analysis by a 2-D dynamic effective stress FEM for a breakwater on a soft clay are presented

Earthquake-Induced Settlement in Soft Grounds

Earthquake-induced settlements in clay is derived from both undrained shear deformation and post-earthquake volume change. The former is assumed to be time-independent while the latter must be time-dependent. To determine the characteristics of cyclic-induced settlements, the authors have carried out a family of cyclic triaxial tests followed by drainage on the plastic marine clay. In every test, shear strain and excess pore pressure were measured during undrained stage and volume change was measured during dissipation of excess pore pressure. In the present study, in particular, the results from cyclic triaxial tests were formulated in order to predict the variations of pore pressure with number of load cycles. An excess pore pressure model was used together with the consolidation theory to evaluate the total settlements and their time-dependent variations due to dissipation of cyclic-induced pore pressure. The results of analysis using the proposed method provide a basis for evaluating the post-earthquake settlement in soft grounds

Why is the bandwidth of sodium observed to be narrower in photoemission experiments?

The experimentally predicted narrowing in the bandwidth of sodium is interpreted in terms of the non-local self-energy effect on quasi-particle energies of the electron liquid. The calculated self-energy correction is a monotonically increasing function of the wavenumber variable. The usual analysis of photo-emission experiments assumes the final state energies on the nearly-free-electron-like model and hence it incorrectly ascribes the non-local self-energy correction to the final state energies to the occupied state energies, thus leading to a seeming narrowing in the bandwidth.Comment: 9 page

Dispersion Interferometer Using a Modulation Amplitude on LHD

Since a dispersion interferometer is insensitive to mechanical vibrations, a vibration compensation system is not necessary. The CO2 laser dispersion interferometer with phase modulations on the Large Helical Device utilizes the new phase extraction method which uses modulation amplitudes and can improve a disadvantage of the original dispersion interferometer: measurement errors caused by variations of detected intensities. The phase variation within ±2 × 1017 m?3 is obtained without vibration compensation system. The measured line averaged electron density with the dispersion interferometer shows good agreement with that with the existing far infrared laser interferometer. Fringe jump errors in high density ranging up to 1.5 × 1020 m?3 can be overcome by a sufficient sampling rate of about 100 kHz

Human-induced marine ecological degradation: micropaleontological perspectives

We analyzed published downcore microfossil records from 150 studies and reinterpreted them from an ecological degradation perspective to address the following critical but still imperfectly answered questions: (1) How is the timing of human-induced degradation of marine ecosystems different among regions? (2) What are the dominant causes of human-induced marine ecological degradation? (3) How can we better document natural variability and thereby avoid the problem of shifting baselines of comparison as degradation progresses over time? The results indicated that: (1) ecological degradation in marine systems began significantly earlier in Europe and North America ( approximately 1800s) compared with Asia (post-1900) due to earlier industrialization in European and North American countries, (2) ecological degradation accelerated globally in the late 20th century due to post-World War II economic growth, (3) recovery from the degraded state in late 20th century following various restoration efforts and environmental regulations occurred only in limited localities. Although complex in detail, typical signs of ecological degradation were diversity decline, dramatic changes in total abundance, decrease in benthic and/or sensitive species, and increase in planktic, resistant, toxic, and/or introduced species. The predominant cause of degradation detected in these microfossil records was nutrient enrichment and the resulting symptoms of eutrophication, including hypoxia. Other causes also played considerable roles in some areas, including severe metal pollution around mining sites, water acidification by acidic wastewater, and salinity changes from construction of causeways, dikes, and channels, deforestation, and land clearance. Microfossils enable reconstruction of the ecological history of the past 10(2)-10(3) years or even more, and, in conjunction with statistical modeling approaches using independent proxy records of climate and human-induced environmental changes, future research will enable workers to better address Shifting Baseline Syndrome and separate anthropogenic impacts from background natural variability.published_or_final_versio

Extension of the measurable temperature range of the LHD Thomson scattering system

The large helical device Thomson scattering system was designed for the target electron temperature (Te) range, Te = 50 eV?10 keV. Above 10 keV, the experimental error becomes rapidly worse. In order to obtain reliable Te data in the temperature range above 10 keV, we are planning to extend the measurable Te range by following two methods. First we have installed one more wavelength channel that observes shorter wavelength region in polychromators. Next applying forward scattering configuration is another candidate. We estimate the data quality when the two methods are used. Both of the two methods are expected to improve Te data quality at Te ? 10 keV