Humanity faces Potentially Significant Risks: Large Dams Built in Earthquake Belts

Jiuping Xu * and Yi Lu

An important but usually ignored issue is that most of large dams have been built in earthquake belts around the world, exposing the general populace to potentially significant risk subsequent to dam failure caused by large earthquakes. The 2008 Wenchuan earthquake in China and the 2011 Fukushima Daiichi Nuclear Power Plant crisis in Japan sounded the alarm concerning large dams located in earthquake belts. However, large dams cannot be abandoned, thus prevention, avoidance and transition are recommended as appropriate measures to strengthen the safety of dams located in earthquake belts.

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Multi-Parameter Safety Criterion for Structure subjected to Blasting Vibration

Chen Shi-hai,1,2* Wei Hai-xia,3 Du Hao2 and Lin Cong-mou1

This study calculates the dynamic responses of a three-degree of freedom elastic system with the program to ground vertical excitations induced by blasting. The excitations include measured blasting vibration waves and ideal sine waves. The results show that the blasting vibration waveforms and spectrum characteristics have evident effects on structural dynamic responses because blasting vibration waves are complex signals containing many frequency contents. By decomposition and reconstruction of wavelet packet, the measured blasting vibration velocity signals are transformed into superposition of several simple harmonic waves. Then the structural dynamic response under blasting vibration can be taken as structural dynamic mechanics for structure under a series of simple harmonic loads. A new safety criterion of structure to blasting vibration is put forward by introducing a new concept of velocity factor and normalized energy proportional to structural dynamic calculation. The criterion can reflect the influence of velocity value of structural response under blasting vibration excitation to structural characteristic parameters, as well as particle peak velocity, frequency, duration and energy proportion of blasting vibration signal on structural safety.

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Emergency Material Requirement prediction Model for Natural Disaster based on Wavelet Network

Yu Kun-Peng*, Yang Yu and Li Fei

In order to solve the practical issues of emergency material undersupply and waste in the management of emergency effectively and realize the valid prediction for demand of emergency supplies, the Index Screening based on Rough Set Theory is presented. Such method can result in a reduced indication set by Domain Partition and Attribute Reduction of the fuzzy similarity relation of original index. In order to improve the accuracy of prediction results, establishing the multi input multi output (MIMO) prediction model of wavelet network and determining the variable parameter of prediction network by adopting method of iterative steepest descend and gradually test play better, the characteristics of wavelet network such as self-learning, local approximation and adaptive resolution and fault-tolerant etc. are studied. Finally, by a series of historical seismic data as the training sample, the structure of prediction model is determined. By contrasting the prediction results and the actual results, the effectiveness of the model is verified

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Prediction of Soil Settlement caused by Double-Line Parallel Shield Tunnel Construction

Wei Gang

The method established in the present study includes the horizontal distance “L” between the axes of two tunnels and considers the effect of the first tunnel construction on the second tunnel. Meanwhile, it reflects the asymmetric feature of soil settlement curve. The measured results showed that there was significantly decreased linear relationship between isecond/ifirst and h/(DL). The calculation formulae of parameter isecond and second were proposed.

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Influence of Water Pressure on Crack Propagation of Sandstone under Compression

Rong Guan1,2*, Peng Jun1,3 and Zhou Chuangbing1,3

Cracks propagate under compression of rocks and these cracks are mainly tensile. Shear band can be formed as the result of interaction of tensile cracks and shear failure finally occurs with propagation and interaction of cracks in the rock. It has been found that progressive failure process of rocks is affected by mineralogical composition, grain size, texture and foliation etc. External factors such as the confinement and excavation disturbance also have great effect on progressive failure process of rocks. The influence of water pressure on progressive failure process of sandstone was studied based on the experiment. It was indicated that with increase of water pressure at both ends of the rock sample, crack initiation stress σci had a tendency to increase and crack damage stress σcd and peak strength σf decreased gradually. With increase of the confinement, stress thresholds during progressive failure process of sandstone decreased gradually.

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Building Damage Assessment with VHR Images and Comparative Analysis for Yushu Earthquake,China

Lu L.1*, Guo H.1 and Corbane C.2

In the aftermath of a disaster, one urgent need is to estimate the degree of structural damage to physical infrastructure with adequate reliability and rapidity. The new generation of very high-resolution imagery (VHR, with a spatial resolution of 1 m or less), if acquired after an earthquake, can be used to assess structural damage at the building level. This paper presents the experience of post-earthquake building damage assessment for the Yushu earthquake using VHR imagery by three organizations: the Center for Earth Observation and Digital Earth, Chinese Academy of Sciences (CEODE), the German Aerospace Center (DLR) and the Joint Research Center, European Commission (JRC). The data sources and methodologies employed for building damage evaluation are presented. To assess the reliability of these sources and methodologies, damage assessment maps produced are compared. The intercomparision results indicate that damage assessment maps based on satellite VHR data are capable of capturing the damage distribution. However, these maps are not suitable for providing accurate information on the damage intensity as the results tend to be underestimated in areas where the damage is moderate and overestimated in areas with a high level of damage and many collapsed structures

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Fast Prediction of Typhoon Tracks based on a similarity method and GIS

Xu Zhen1, Zou Liang2, Lu Xinzheng1* and Aizhu1

A fast method for predicting typhoon tracks based on historical data is proposed in this study. A typhoon track database is built containing 44-year typhoon data for China. Based on this database, typhoon tracks similar to the current typhoon are identified via the similarities of the key typhoon track points and geographic information system (GIS) spatial analysis. The central positions of typhoons after 24 and 48 h are quickly forecasted according to these similar tracks. The prediction results can be continuously corrected by the latest position of a typhoon every 6 h. Three typhoons are chosen to demonstrate the predicted typhoon track and 103 typhoons in 10 years are used to validate the accuracy of the prediction. The results indicate that the computing time of the prediction is less than 1 min and the accuracy of the prediction is very close to the official prediction of the China Meteorological Administration (CMA). This method provides a quick and accurate reference for predicting typhoons.

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Fractal Analysis of Permeability for Unsaturated Seepage Flow in Fractured Rock Masses

Guoping Jiang

A physical conceptual model for liquid retention in fractured hard rocks is presented. A fractal model for unsaturated seepage in fractured rock masses of function among capillary pressure, effective water saturation and relative hydraulic conductivity is established. The comparison results of proposed model and the Brook-Corey model indicate that the proposed model seems to be adequate to describe the fractured rocks for small ranges of fracture aperture and the relative conductivity is mainly influenced by the maximum fracture aperture. The proposed model presents a very good description of water and air permeabilities over several orders of magnitude for the whole range of water saturation.

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Evaluation of Potential Failure of Rock slope at the Left Abutment of Jinsha river Bridge along Lijiang-Xamgyi’nyilha railway, China

Zhao Zhiming1*, Wu Guang1, Ali Esamaldeen1,2, Wang Xihua3 and Kou Chuan4

Keeping slope relative stable has very significant meaning in traffic design and the safety of human life. Jinsha river Bridge is located on Tiger Leaping Gorge town along Lijiang-Xamgyi’nyilha railway, China. The left bank slope at bridge site, which composes of moderately thick layer of slate overlain by schistose basalt, is considered as potential instability due to two sets of joint planes. A comprehensive method based on geotechnical field and laboratory analyses, engineering model test and numerical analysis is adopted to assess slope stability under bridge foundation and seismic loads. According to model test, failure mainly initiated at the toe with shear movement along the joint planes, eventually resulting in the sliding along the slope surface and formation of tension crack at the crest of the model. This result coincides with computer-based modeling using Universal Distinct Element Code (UDEC), which shows that slope surface will produce loosening damage and slipping expected along the joint planes under different loading conditions. Moreover, the results of FEM analysis indicates that the rock mass under the main pier has potential shear failure region and it has developed along excavated slope. Through bridge site investigations, the bridge foundation should be strengthened to prevent the slope failure under external forces.

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Dependence between Deficit and Surplus of Precipitation and Forest Fires

Ćurić M1* and Živanović S2.

Creation of forest fires, among other conditions, is being caused by the climate and the humidity of the burning material. The trend of deficit and surplus of daily, monthly and annual precipitation, affects on the condition of the burning material and thus the possibility of the fire. Comparative analysis has been done based on the time of fire occurrence and trend of deficit and surplus of daily, monthly and annual precipitation. The analysis was done on the basis of meteorological measurements at the meteorological station Negotin, for the period 1991-2008. The periods with deficit of the precipitation are coincident with the periods of forest fires appearing.

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Development of Landslide-Risk Assessment Model for Mountainous Regions in Eastern Korea

Lee S.W.,1* Kim G.,1 Yune C.Y.1 and Ryu H.J. 2

Recently, damage from landslides caused by severe rain storms and typhoons is reported often. Now that due to domestic geomorphological characteristics, many cities are developed and infrastructure such as roads and railways are constructed nearby mountain area the damages of landslides are very serious in Korea. It is important to figure out areas with high landslide-risk and arrange the proper measures in order to prevent such damages effectively. Mountainous region in eastern Korea, which experiences landslides every year, especially requires regional preparation model that reflects its climate characteristic. In this study, landslide-related information such as geomorphological charact¬eristics, soil properties, rainfall, vegetation and forest fire history of 423 sites was investigated through field survey, disaster reports and existing GIS database. Then landslide-risk assessment model was suggested by performing logistic regression analysis on them. The results of comparing calculated probabilities of landslide with the occurrence of actual landslides showed a classification accuracy of 91%.

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Response Time Reduction in ‘Response and Relief’ Phase of Earthquake using Dijkstra’s Algorithm

Nigam Vivek* and Jethoo A. S.

In this paper a study on the earthquake response operations and pre-planning and post-planning methodologies for the earthquake in highly populated urban areas has been carried out. It focuses on the substantial use of transportation system in urban areas to carry out real time responses during earthquake. A concept of disaster response routes to minimize the response time and a shortest path finding algorithm have been used to determine the shortest routes to deliver the first responders, first aid commodities, medical facilities to the affected areas and for the transportation of casualties to the hospitals, Dijkstra’s shortest path computer algorithm is used in this study to minimize response time during emergency. This study deals with the issue of pre-planning of the supply of first-aid commodities (medicine, food, clothing, pure water, power, machinery, etc.) and emergency personnel to disaster affected areas by building a generic modeling framework to be used in case of earthquake. Since Dijkstra’s algorithm is easy to implement and when it is implemented as the priority queues or Fibonacci heaps, it runs more efficiently and gives precise results in real time applications. This algorithm is applied on the road network of Malaviya Nagar Territory in Jaipur city

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