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Mori T.,Tohoku University | Tobita Y.,Tohoku Gakuin University | Okimura T.,Construction Engineering Research Institute Foundation
Soils and Foundations | Year: 2012

The 2011 off the Pacific Coast of Tohoku Earthquake resulted in severe damage to housing and housing lots. In particular, the hillside embankments for residential use surrounding the downtown of Sendai city suffered serious damage. Many hillside lands which had been damaged during the 1978 off Miyagi-Prefecture earthquake were subjected to further damage. Typical damaged hillside embankments in Sendai city were investigated and the causes of the damage were discussed in this paper. The main cause of the damage to housing was not the seismic motion but the ground displacement of the fill embankment. A comparison of the damage from the 2011 earthquake with that from the 1978 earthquake indicates that the countermeasures constructed after the 1978 earthquake performed well in that they prevented large landslide type failure; however, they were not successful in reducing the amount of damage to housing or housing lots due to ground displacements from cracks, differential settlement, and shallow slips. A classification of failure types of fill embankment is proposed to be of assistance in the choice of countermeasures. © 2012 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.

Otsuka I.,Taisei Corporation | Taki H.,Taisei Corporation | Aoki T.,Taisei Corporation | Shimo M.,Taisei Corporation | And 3 more authors.
Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics | Year: 2012

This project is named 'Marmaray' which is a coined word combining the sea of Marmara and railway. The Marmaray Project is the upgrading of approximately 76 kilometers of commuter rail to improve the railway system in Istanbul metropolitan area. Railway tracks will be connected between Asia and Europe through a tunnel under the Bosphorus Strait. Tunnels and stations have been and will be constructed by some methods such as immersed tunnel, shield tunnel, mountain tunnel, and cut and cover in 13.6 km length of this project. In this report, it is described that the observational construction management by field measurement is performed in large scale underground railway station (Sirkeci station) by means of NATM. © 2012 Taylor & Francis Group, London.

Kunimatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Kitamura Y.,Construction Engineering Research Institute Foundation | Yokota A.,Rion Co. | Uchida H.,Tobishima Corporation | And 6 more authors.
INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | Year: 2014

In INCE/J, the prediction method of the first version of INCE/J RTV-Model named INCE/J RTV-Model 2003 for environmental impact assessment on ground-borne vibration induced by the road traffic was published for flat roads in 2003. Lvio (10 percentile-exceeded frequency weighted acceleration level) is used in the vibration evaluation for an environmental assessment in Japan. For this reason, the prediction in the model was based on a method to calculate the summation in decibel considering traffic volume within the defined time from the unit pattern which is the time history of vibration acceleration level at the prediction point when one vehicle runs on the road. The unit pattern could be calculated by using a simply empirical equation for the distance attenuation by Bornitz. In order to extend the previous model to a new applicable model for both cutting- And banking-structure roads, numerical simulations were performed. These results were summarized in this paper.

Iwano M.,Taisei Corporation | Kobayashi S.,Taisei Corporation | Kaneko T.,Taisei Corporation | Ikeda K.,Taisei Corporation | And 2 more authors.
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013 | Year: 2013

Marmaray project is currently under construction in Istanbul, Turkey to provide a rail link between Europe and Asia crossing the Bosphorus Strait. Sirkeci station is the deep underground station, in which excavation works are now on going by conventional tunneling. This station has so complicated configuration with not only 3 horizontal tunnels with several connections and 4 large ventilation and platform chambers connecting to two ventilation shafts, but also a couple of the shallow inclined shafts and horizontal tunnels to the two entrances. Furthermore, Sirkeci is located at the center of historic district which is registered as "The World Heritage". In densly populated area, the excavation works have to be done just below the unsound existing buildings. In this paper, the construction procedure of such complicated underground structures under severe conditions is reported, together with the countermeasures in tunnels to reduce the damage risk against the existing unsound buildings. For large cross over tunnels, whose cross section partially exceed more than 200 m2, the unique excavtion proceedure by using both of tunnel boring machine (TBM) for main tunnel and conventional tunneling for enlargement to final tunnel configulation has been applied and good performance has been achieved. © 2013 Taylor & Francis Group.

Kakugawa K.,Hiroshima Institute of Technology | Futagami T.,Hiroshima Institute of Technology | Matsuda M.,Hiroshima Institute of Technology | Sakai H.,Hiroshima Institute of Technology | And 4 more authors.
WIT Transactions on the Built Environment | Year: 2013

A large number of hazards all over the world are caused by debris flows and landslides, and this is especially so every year in Japan. In June 1999, August 2005, July 2010 in the Hiroshima prefecture, and in July 2009 in the Yamaguchi prefecture, there were many hazardous occurrences of large debris flows and landslides owing to torrential downpours. Through the survey made of these hazards it seems that there are two main factors causing the increase of hazards and consequent risks. The two main factors are the contiguity of urbanization of hillsides and the bio-deterioration of mechanical structures of the ground on hillsides caused by eutrophication (nutrient enrichment). The eutrophication promotes microbial activities that deteriorate the mechanical structures of the ground on the hillside slopes. Microorganisms promote the weathering of rocks to soils and cause aggregation of soils by their metabolites. Aggregated structures of soils wet the ground to decrease the resistance to landslides. It seems that microbial activities accelerate the occurrence of debris flows. The eutrophication causes the bio-weathering of the ground. This contribution describes the investigation of the relationships between debris flows and microorganisms activated by eutrophication of hillside ecosystems in order to construct a precise model of occurrence of debris flows. The model may be able to mitigate the hazards. Identification of microorganisms in the subsurface of the hillside was obtained by using a molecular biological technique. It was observed that the values of the eutrophication index (TC and TN) are high in the weathered rock and low in the unweathered rock. Thus weathering of rock can cause the increase of the risk due geological hazards of landslides and debris flows. © 2013 WIT Press.

Hirao Y.,Kobayasi Institute of Physical Research | Ohta K.,OYO Seismic Instrumentation Corporation | Kunimatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Kitamura Y.,Construction Engineering Research Institute Foundation
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013

Residents of buildings experience discomfort or annoyance from ground-borne vibration sources such as rail transit systems, road traffic, construction sites, and industrial plants. The building vibrations may cause discomfort such as sleep disturbance because the vibrations experienced are often greater than the ground vibrations near the building. Such vibration amplification in each building is induced by typical structural resonances in the horizontal direction. It is possible that the structural resonances of the buildings are affected by the frequency characteristics or magnitudes of the ground-borne vibrations onto the substructure of buildings. We developed a "reference horizontal exciting system" to investigate the structural resonances of buildings under certain ground-borne vibration conditions. The system consists of two unbalance weights, three transmission gear wheels, a pulse-motor, and a pulse-motor controller. The unbalance weights are horizontally rotated in sync by the transmission gear wheels and the pulse-motor. The system generates a unidirectional and horizontal force that is exactly timed for a sinusoidal signal. The buildings were excited in a horizontal movement by our system through the ground near the substructure of the buildings. The horizontal structural resonances of the two-story wooden and steel constructed house were investigated by vibration measurements using by the system. The resonance curves on the second floor of each house were calculated. Moreover, it is shown that the second floor of the wooden house was rocked in a rotatory motion by using the Lissajous curves of displacements at the three measurement points on the horizontal plane on the second floor.

Kunimatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Hirao Y.,Kobayashi Institute of Physical Research | Kitamura Y.,Construction Engineering Research Institute Foundation
Journal of Modern Transportation | Year: 2012

Ground-borne vibrations caused by vibration sources such as road traffic and construction exhibit complicated properties during propagation from the vibration source to the inside of a building. In the present paper, a numerical analysis technique for the system of vibration source and propagation path of ground vibration is developed in order to systematically determine the propagation properties of the vibration as part of developing a predictive technique for exposure evaluations by vibrations in three directions at receiving points of vibration in the human body. First, the exciting forces in three directions for input into the numerical computation are inversely-estimated by using the measured acceleration records of the measurement points, which are near the vibration source. The thin-layered element method is used for numerical computation of the ground vibration. Then, the calculation results for the ground vibration obtained by using the estimated exciting force are compared with the measured results, and the influence of the stratified structure of the ground on the exciting force and the propagation properties of the ground vibration are studied. From these results, in a prediction of the ground vibration in three directions, it is emphasized that it is necessary to consider the influence of horizontal exciting force, although attention has been paid to only the vertical exciting force for simulating ground vibration. © 2012 JMT. All rights reserved.

Uenishi K.,University of Tokyo | Sakurai S.,Construction Engineering Research Institute Foundation
Rock Dynamics and Applications - State of the Art: Proceedings of the 1st International Conference on Rock Dynamics and Applications, RocDyn-1 2013 | Year: 2013

A seaquake, caused by an earthquake, is shaking experienced on board a floating structure at sea. The shaking is most often felt as strong vertical impact, but its generation mechanism has not been fully clarified yet. Here, we study elastodynamic wave interaction in a one-dimensional seabed-sea water system and try to better comprehend the essential mechanism underlying seaquake generation. Our analytical results show if both seabed and sea water behave linear elastically and are subjected to incidence of a harmonic longitudinal wave, the wave interaction may induce resonance. Such systematic resonance might not be found if we assume, like in ordinary hydrodynamic analyses, rigid seabed covered by a layer of elastic water. The rigid seabed assumption might be unable to offer a precise dynamic description of the seabed-sea water system and the seaquake generation. Application of the concepts developed in rock dynamics may be useful in further study of seaquakes. © 2013 Taylor & Francis Group.

Uenishi K.,Kobe University | Takahashi H.,Sumitomo Mitsui Construction | Yamachi H.,Sumitomo Mitsui Construction | Sakurai S.,Construction Engineering Research Institute Foundation
Construction and Building Materials | Year: 2010

A fully three-dimensional finite difference code is developed for simulating wave and fracture propagation in solids and it is used to study the physical process associated with blasting demolition of reinforced concrete (RC) structures on a PC basis. The code is validated by comparing the numerical results with those obtained by a blasting experiment using a RC beam specimen in the field. A real example of blasting demolition of piers of a road bridge is shown and the usability of the code is tested. Detailed computations have revealed that the use of a simple tensile fracture criterion can reproduce the observed fracture patterns precisely. © 2010 Elsevier Ltd. All rights reserved.

Sakurai S.,Construction Engineering Research Institute Foundation
Acta Geotechnica | Year: 2010

This paper deals with the modeling of jointed rock masses reinforced by rock bolts. It is well known that rock bolts are extremely effective in reinforcing jointed rocks. However, if a continuum approach is adopted for modeling jointed rock masses, it is often misleading to evaluate the effectiveness of the rock bolts by numerical analyses such as the finite element method. This may be due to the fact that since no more joints exist in the continuum, the effectiveness of the rock bolts in constraining the relative displacements along the joints cannot be evaluated properly. In order to investigate the reinforcement effect of rock bolts, physical model tests were performed in the laboratory. The test results revealed that jointed rock masses should be modeled as an equivalent continuum after the installation of rock bolts and that the mechanical parameters of the equivalent continuum should be evaluated by considering the reinforcement effect of the rock bolts. Therefore, the values of the mechanical parameters differ from place to place in accordance with the relation between joint orientation and rock bolt direction, even though joint systems are homogeneous. In conclusion, in the continuum approach for modeling jointed rock masses, it should be emphasized that rock bolts and jointed rock masses should not be modeled separately but should be modeled simultaneously by considering the reinforcement effect of the rock bolts in constraining joint movement. The modeling of shotcrete reinforced by steel ribs is also discussed in comparison to the modeling by rock bolts. © 2010 Springer-Verlag.

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