Dynamic responses of anchored rock slope under earthquake - A numerical study

Peng Ningbo1,2*and Yan Zhixin 1,2

In this study, FLAC3D is applied to stimulate the dynamic responses of anchored and unanchored rock slope under earthquake. The horizontal displacements of the surface, top and inside of slope at different elevations,axial force of rock bolt and interaction between rock bolt and the surrounding rocks are presented and discussed. The average tensile strain and nominal shear strain are defined and employed acting as the criteria for slope failure and reinforcement effects of rock bolt. The results show that rock bolt can reduce shear strain effectively of lower slope and decrease the tensile strain of upper slope. The Fourier analysis is used for further study of dynamic characteristics of slope. The acceleration Fourier spectrum displays that the acceleration amplitude increases as the elevation rises. What is noticeable is that it is at slope shoulder that strong vibration of single frequency occurs. Comparative study shows the effect of strengthening rock mass using rock bolt resembles that of increasing elastic modulus and reducing Poisson’s ratio of rock mass. The results show that rock bolt can significantly improve the anti-seismic capacity of anchored slope.

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Cold Sea Waters Induced by Cyclogenesis in the East Sea

Choi Hyo

The occurrence of cold sea waters induced by cyclogenesis along the eastern coastal sea of Korean peninsula was investigated from March 28 through 30, 2004, using NOAA MCSST sea surface temperature (SST) satellite pictures and a three-dimensional Weather Research and Forecasting Model (WRF)-version 3.3 with a one way-triple techniques. On March 28, westerly wind under a high pressure prevailed in the Gangneung coast and the open sea produced northeastward wind driven current, resulting in the northward intrusion of warm sea waters by the East Korea Warm Current toward the north along the Korean eastern coast. Under this situation,daily mean SST near Gangneung coastal sea and open seas of the East Sea were 10.50C. On March 29, low pressure with cold front in Bohai Sea between China and Korea produced a cyclonic air flow, which could cause strong southwesterly marine surface wind in the Korean eastern coastal sea near the study area and a strong southeastward wind driven current. This current resulted in both upwelling of deep cold waters towards the sea surface and spreading outward in the coastal sea and the intrusion of cold waters of the North Korea Cold Current from the Korean northeastern coast toward Gangneung city along the coastline. On March 30, as the low pressure of 1013 hPa was more intensified with a decrease of 5 hPa to 1008 hPa in the East Sea (cyclogenesis) could cause the strong intrusion of cold waters from the northeastern coast into the southeastern and its cold front passed by the study area, both northwesterly wind along the coast and westerly wind in the offshore, resulting in a cold sea outbreak of 90C with a decrease of 1.50C than one on March 28.

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Bhuj Earthquake 2001 - Study of Traditional Practices for Inclusion in Disaster Mitigation and Preparedness Strategy

Macwan Jayesh George

This study focuses on the necessity of developing a network to collect data of various traditional practices as forecasting tools for earthquake prediction so that these could be included in mitigation and preparedness strategy. Before Bhuj earthquake 2001, some abnormal incidents and homely events were observed. These types of events/incidents, when corroborated in other earthquakes can give indication of expected earthquake but exact place and time may be known only with the help of other scientific tools.

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Numerical Validation of First Passage Failure Probability about Wind-Induced Buffeting Response in Long-span bridges

Zhao L. and Ge Y.J.

Based on the current buffeting theories and reliability assessment methods, a numerical simulation approach to the first passage probability for a long-span bridge under buffeting actions is developed. The response spectrum analysis method is first adopted to calculate buffeting response in the frequency domain. The time history of structural responses induced by buffeting is numerically simulated by trigonometry series compose approach based on the buffeting spectrum results. While a large amount of samples are generated by Monte-Carlo simulation technique, it is relatively easy to numerically obtain the probability of first passage failure in buffeting responses of a long-span bridge. Two numerical examples referring to buffeting deflections of Jiangyin Suspension Bridge and Yangpu Cablestayed Bridge in China have been considered. Compared with the corresponding results of three approximately analytical approaches, it can be concluded that the proposed numerical method is quite precise and effective in their use and hence can be exactly used in calculating, especially in detailed design stages, the probability of bridge buffeting responses surpassing the prescribed safety barriers during its service time.

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Experimental study on the permeability of phyllite under unloading confining pressure and high temperature

Meng Lubo and Li Tianbin

Permeability experiments on the deformation and failure processes in phyllites were carried out using a MTS815 Flex Test GT instrument under unloading confining pressure and high-temperature conditions. The permeability of phyllite in deformation and failure processes was analyzed and the relationship between permeability and volume strain was discussed. The effect of temperature on the permeability of phyllite was studied. Results show that the deformation and penetrability of phyllites can be divided into four phases: elastic compression deformation, elastic expansion deformation, expansion damage and after-failure phase. The rock penetrability is small and remains nearly unchanged during the elastic compression deformation phase, but obviously increases during the elastic expansion deformation phase. The rock permeability during the elastic expansion deformation phase is 2.4 times higher than that during the elastic compression deformation phase. The rock permeability during the expansion damage phase is 3.3 times higher than that during the elastic compression deformation phase. The permeability after rock failure is 8.5 times higher than that during the elastic compression deformation phase. Unloading confining pressure causes strong expansion of the rock volume, which leads to higher rock penetrability under unloading than under loading conditions. The test temperature is lower than the phyllite thermal rupture threshold temperature and the phyllite permeability decreases with increased temperature.

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Investigation on Behaviour Aspects of Tsunami Resistant Structures – An Experimental Study

Palaniappan Meyyappan1*, Thimmayan Sekar2 and Chandrasekaran Sivapragasam1

The studies on tsunami resistant buildings are still in its inception. Many works have been reported on various model studies to investigate the pressure variation due to tsunami force created under the laboratory conditions. This work suggests model studies carried out directly near the sea coast, particularly to reflect the behaviour of foundation of building to tsunami loads. The study also considers the effect of shape of building and the type of building materials that will be suited for tsunami effect. The investigations reveal that in general, circular buildings are better suited than the conventional rectangular shaper buildings. Further, the presence of openings is an added advantage.

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Permo-Triassic Deposits of Shorjestan Area, Central Iran: The Palynological Report of the Greatest Phanerozoic Disaster in Iran

Noroozpour H.,1* Yousefi Rad M.2, Arian M.1, Solgi A.1 and Nezam Vafa N.3

Upper Permian deposits of Shorjestan area, central Iran included marly limestone, red to amethystine limestone with layers of red, green and gray shales followed by lower Triassic deposits as continuous with dark shale lithology, marly limestone, red and green shales and igneous rocks. In studied sequence there are terrestrial and rarely marine palynomorphs with low varieties and frequencies and fair preservation. Hambast Formation deposits are attributed to Upper Permian on the basis of stratigraphic distribution of some palynomorphs such as Florinites balmei, Alisporites nuthallensis, Vittatina lata, Laevigatosporites ovatus. Aforementioned palynoflora are common with some parts of Saudi Arabia Upper Permian palynoflora (OSPZ6 assemblage zone, Changhsingian). Regarding mass extinction of end-Permian and disappearance of most vegetation and lack of time for recovery, it may find palynoflora with low varieties such as Alisporites sp., Falcisporites sp. and fungal spores in lower Triassic deposits of studied section. Notable frequencies of fungal spores and plant tissues in lower Triassic deposits probably are related to vegetation disappearance in boundary of Permo-Triassic (PTB) and aggregation of corruptible organic matters.

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Reliability and Vulnerability Analysis Methodology for Comprehensive Transportation Systems under Influence of Disasters

Yan Xuedong* and Zhao Hui

Because of the historical disasters’ serious threats to comprehensive transportation systems, the reliability and vulnerability assessment for the systems has become one of the key performance indicators. The methodology for analyzing the reliability and vulnerability of comprehensive transportation networks is presented. A disaster influence matrix for evaluating the risks in comprehensive transportation systems is discussed.

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