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1.
Data archives of seismic fault-induced damage 总被引：1，自引：0，他引：1
The study of earthquake engineering requires an understanding of various processes by which structures are seriously damaged. For this, archiving available data in a systematic way will be quite necessary. Taskforces of both Japan Society of Civil Engineers (JSCE) and Japan Geotechnical Society (JGS), with a mission of establishing remedial measures for fault-inflicted damage to civil infrastructures, have been investigating previous examples of fault-related damages. Some of their important activities were further expanded as a subject of EqTAP project (Development of Earthquake and Tsunami Disaster Mitigation Technologies and Their Integration for the Asia-Pacific Region). This paper introduces some examples from the JSCE/JGS/EqTAP Data Archives, which can give some hints for rational remedial or design measures for civil-infrastructures whose constructions across faults were/are unavoidable. 相似文献
2.
During the dynamic response of multiple partially or fully embedded structures, the subgrade medium at the sides of the structures not only generates the soil-structure interaction forces but also transmits the motions from one structural body to others. With Winkler's hypothesis, these forces and motions are formulated in the time-domain in a simple form utilizing the frequency-domains formulations. The validity of the developed formulations is examined using small-scale-model test results obtained for piles in a synthetic ground. A numerical example is provided to demonstrate the approach proposed and the formulations developed. The simplified time-domain formulations are found to be numerically efficient and yet capable of predicting the behaviour reasonably well. 相似文献
3.
Few building codes contains provisions fault surface ruptures and accompanying soil deformations which constitutes a great risk to human lives, buildings and infrastructure. A numerical and experimental comparison show a fair agreement of result. Analysis of “real” scale show the how water increases the incompressibility of wet soil causing shear deformations to become larger and conjugate ruptures to appear for reverse faults. Field observations and numerical analysis indicates that horizontal compression of soil surrounding underground structures should be taken into account in design. 相似文献
4.
A differential equation is formulated for the dynamic response of ground medium by using a simplified ground model. Applying Galerkin's procedure for weighted residual, this equation leads to a governing equation only at the ground surface. The equation indicates that the ground surface behavior can be computed even further by a simplified model. By solving the governing equation for the boundary conditions along the surface, expressions in simple closed forms are developed for the dynamic response analysis of a massless rigid foundation that rests on the ground surface. Despite their significant simplicity, the developed expressions compute the values very close to those computed by far more complex rigorous solutions. They are found to be capable of capturing the important characteristics of the dynamic ground behavior well. 相似文献
5.
K. Sassa B. He T. Miyagi M. Strasser K. Konagai M. Ostric H. Setiawan K. Takara O. Nagai Y. Yamashiki S. Tutumi 《Landslides》2012,9(4):439-455
The distinctive bathymetric feature exists in the Suruga Bay, Japan. It has been called as Senoumi (Stone flower sea) from old times. Senoumi is a 30?km wide and 20?km long concave feature. Its origin has not been explained yet; however, the feature might be a combined consequence of intensive tectonic activity in the plate border, landslides, and a submarine flow coming from the Oi River. If the Senoumi was caused by a landslide, the latter would be larger than any on-land landslide in Japan. The downshelf “exit” from this feature is much narrower than its central part. This is not usual shape of landslides, but it is similar to the liquefied landslides such as those in quick clays which mobilize great strength reduction after failure. To study Senoumi as a landslide, the shear behaviors of the following three soil samples were investigated by the cyclic and seismic undrained stress control ring shear tests. One sample is volcanic ash taken from the base of landslide deposits (mass transport deposits), from 130 to 190?m deep layer below the submarine floor which was drilled and cored by the Integrated Ocean Drilling Program Expedition 333. Another two samples are the Neogene silty–sand and silt taken from the Omaezaki hill adjacent to the Senoumi, because the shear zone might have been formed in Neogene layers extending from on-land to the continental shelf. The largest strength reduction from peak to steady-state shear resistance in the undrained cyclic loading test was found in volcanic ash. The strength reduction in Neogene silty–sand was smaller than volcanic ash, while the Neogene silt mobilized the least post-failure strength reduction. An integrated model simulating the initiation and motion of earthquake-induced rapid landslides (landslide simulation (LS)-RAPID, Sassa et al. Landslides 7–3:219–236, 2010) was applied to this study. The steady-state shear resistance and other geotechnical parameters measured by the undrained ring shear tests and the greatest strong motion record in the 2011 off-the-Pacific Coast of Tohoku earthquake (M w 9.0), also known as “2011 Tohoku Earthquake” at the observation point MYG004 (2,933?gal) were input to this model. As the result, it was found that landslides would be triggered by 0.30–1.0 times of MYG004 in volcanic ash, 0.4–1.0 times of MYG004 in Neogene silty–sand and Neogene silt, though the depth and area of triggered landslides were different in soils and intensity of shaking. Feature, created by LS-RAPID using the parameters of volcanic ash, was most similar to the Senoumi in depth and extent. The result obtained from this study includes a hypothesis to be proved, but presents the strong need to investigate the risk of the large-scale submarine landslides which could enhance tsunami wave and possibly enlarge the submarine landslide retrogressively into the adjacent coastal plain by the upcoming mega earthquake in the Nankai Trough. 相似文献
6.
The 8th October 2005 Kashmir Earthquake of magnitude 7.6 triggered a huge landslide 3.5 km upstream of Hattian Bala town in
the state of Azad Jammu Kashmir of Pakistan. The debris mass blocked two tributaries of the Karli branch of the Jhelum River
and was breached on 9th February 2010. This debris dam provided us with a rare opportunity to keep careful and continuous
eyes on its post-earthquake behavior especially as it was a serious threat to people living along the lower reaches of both
the Karli and Jhelum Rivers. This paper describes post-formation behaviors of the debris mass, breaching-inflicted changes
of not only the debris mass but also both upstream and downstream reaches based upon laser-scanned images of landforms and
Differential Global Positioning System survey results. 相似文献
7.
8.
Measurement of debris mass changes and assessment of the dam-break flood potential of earthquake-triggered Hattian landslide dam 总被引：1，自引：1，他引：0
Ahsan Sattar Kazuo Konagai Takashi Kiyota Takaaki Ikeda Jorgen Johansson 《Landslides》2011,8(2):171-182
The Hattian landslide, which was triggered by the 2005 Kashmir earthquake, formed one of largest landslide dams in the world and it has posed a serious threat of flooding to people living in the lower reach of the Jhelum River. In order to understand deformation occurring in the body of the dam, physical measurements using a Differential Global Positioning System (DGPS) were conducted. Gradual deformation and slowly developing backward erosion initially were observed, leading eventually to a sudden creation of a deep hollow on the downstream slope of the landslide dam. The dimensions of this eroded gully were determined by laser scanning, and the results showed a significant loss of soil volume and a large change in the body of the dam. A breach formation model was used to predict the outflow hydrograph generated by constant downcutting of dam during a breaching event. A run-off analysis of the outflow hydrograph was conducted to evaluate inundation levels of flood waves in case the dam is breached. Hazardous downstream locations were identified near the junction of the Karli and Jhelum Rivers, suggesting a need for early warning system in order to avoid loss of lives. 相似文献
9.
The use of super-elevations that a forced vortex flow leaves on the valley walls of a curved flume is a plausible approach toward estimating debris flow velocities in earthquake-induced geo-hazard studies. The centrifugal force of a speeding flow is responsible for a higher flow depth on the outer bend. However, in reality, a flow is not steady, and only the highest flow-marks are left at the outer and inner bends of the flow, which can lead to an inaccurate estimation of the actual velocity. Seeing the real scenario of the field, a series of numerical flume tests using smoothed particle hydrodynamics (SPH) is conducted to validate the estimation of debris flow velocities from flow-marks. Velocities estimated from flow-marks are lower than real velocities near the source region, but they converge to real velocities as the distance to the source increases. Based on several simulations, a best-fit line is proposed for adjusting debris flow velocity from mud-marks, and it is used to estimate flow velocities of the well-documented debris event called “Shiraito river debris flow,” which happened near the rim of the Hakone Crater, Kanagawa Prefecture, Japan, ensuing from the 1923 Great Kanto earthquake. 相似文献
10.
Long-term earthquake observations at different tunnel sites within a variety of alluvial soil deposits have clearly demonstrated that a tunnel, which exhibits rather flexible nature within its surrounding soil, follows closely the motion of the soil mass during an earthquake. Therefore, coating a tunnel with a soft material will be a possible measure for minimizing damage to tunnels. This paper provides a clear perspective on the feasibility of this measure by using simple solutions to idealized problems. 相似文献