Disaster Advances

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Disaster Advances

Vol. 5(4) October 2012

Research on Three-dimensional Soil Deformation induced by Double-O-Tube Shield Tunneling

Gang WeiP1P*, Jie HongP2P and Xinjiang Wei P1,

The Double-O-Tube (DOT) shield is a new tunnel construction method and the characteristics of three-dimensional (3D) soil deformation induced by DOT shield tunneling have not been deeply studied. The formula for settlement calculation caused by soil loss was derived from the random medium theory. Considering the friction between the cutter facade, side and soil the formula for soil deformation was deduced using Mindlin solution. The 3D formula for soil deformation was deduced from a combination of the additional driving positive force with the shell frictional resistance force. From the results it can be concluded after considering various factors that, the calculated values are in good agreement with the measured values. The uplift in front of the shield face is mainly caused by friction between shell and soil. Ground settlement is mainly caused by soil loss and it is laterally in accordance with the normal distribution. This conclusion is significant for practical guidance during DOT shield tunnel construction.

Effects of pullout direction and anchor inclination on computation of pseudo-static uplift capacity for strip anchors in sand

Rangari Sunil M., Choudhury Deepankar* and Dewaikar D. M.

Ground anchors are subjected to tensile loads and are extensively used for civil engineering structures like transmission towers, sheet piles, waterfront structures etc. The behaviour of ground anchor is complex under seismic conditions and underestimating the seismic effect leads to the failure of entire structure. Hence the researchers should give the prior importance to compute seismic uplift capacity of such ground anchors under earthquake loading conditions. In this study, an analytical method to compute the uplift capacity of strip anchors under seismic conditions for various positions of pullout load and anchor inclinations is described. The Kötter’s equation is used to obtain the soil resistance against the uplift movement of anchor on assumed simple planar failure surface. Effects of pullout load inclination and anchor inclination are obtained on uplift capacity factor Fγd using pseudo-static approach with the limit equilibrium method. The uplift capacity factor for unit weight component (Fγd) is determined for various combinations of input parameters like soil friction angle, embedment ratio, inclination of anchor, pullout directions and both the horizontal and vertical pseudo-static seismic accelerations. It is observed that with increase in seismic accelerations, both in horizontal and vertical directions, the uplift capacity factor decreases significantly. However, the uplift capacity of horizontal strip anchors increases with increase in embedment ratio, as expected, in seismic conditions also. Significant variations in Fγd values are observed with change in pullout position and even with change in inclination of anchor. The results are presented in non-dimensional uplift capacity factor in graphical and tabular form.

Maximum Local Energy Method for Multispectral Image Fusion in Remote Sensing System

Lifeng Zhang*, Huimin Lu and Seiichi Serikawa

This paper presents an image fusion method suitable for Multispectral remote sensing image fusion, based on multi-resolution analysis in remote sensing system. This method dedicates to fuse multispectral low-resolution remotely sensed images with a more highly resolved panchromatic image. The high-resolution regions of each remotely sensed image coefficients are extracted by beyond wavelet transform (BWT). BWT is a multi-resolution analysis, whose basis functions are directional edges with progressively increasing resolution. The advantage of BWT is well adapted to cured-singularities and point-singularities. There are two obvious virtues of this method. First directional detail coefficients matching image edges, which is better than obtained in separable wavelet domain. Secondly, selection strategy of maximum local energy (MLE) between low-frequency coefficients is more effective. Experiments have proved that the MLE is a new way for remotely sensed image fusion, which can get well performance. Fusion results in beyond wavelet transform are also compared.

Importance of Ductile Detailing in Earthquake Resistant Reinforced Concrete Frame Building

Bhattacharya Shankha Pratim

The past earthquake experiences in India clearly demonstrated that the typical structural design and construction methods lacks the basic seismic resistance criteria. The implementation of ductile design and detailing practices in ordinary building is one of the major area need to be focused. The overall ductility in reinforced concrete structure is a tough issue. But in some strategic locations of the building structure certain design factor and reinforcement detailing can be adopted to minimise the seismic damage and life threatening collapse. The techniques are simple, inexpensive and elaborately discussed in the bureau of Indian standard code of practice (IS13920:1993). The structures need to be designed to have sufficient strength and ductility for overall safety against earthquake forces. Both the strength and the ductility are combined together to improve its seismic safety. This study discussed the ductile behaviours of the reinforced concrete structures according to Indian code. It also evaluates the earthquake resistance performance of structure based on design and detailing parameters. The curvature ductility in beams with reference to the percentage of reinforcement and design material stress is considered. The behaviour of beam-column joints and the confinement in concrete columns are also addressed.

Using Unified Modeling Language on the Development of Real-Time Remote Monitoring System for Hillslope

Yao-Ming Hong1, Hong-Ting Lyu2, Wen-Pei Sung3*, Yao-Chiang Kan4 and Hsueh-Chun Lin 5

This study developed a real-time remote monitoring system (RTRMS) for monitoring hillslope precipitation using a software system analysis and design methods named unified modeling language (UML). The system structure thus developed comprises three subsystems for gathering/storage /transmission (GST), receiving/sending/control (RSC) and storage/display (SD). The RTRMS also has an embedded system which uses solar energy as the power supply and the General Packet Radio Service (GPRS) modem for wireless transmission. This study also develops the specifications for designing the solar power system. The developed RTRMS has been put to use in the watershed of Chen Yu Lan Creek, Nantou County, Taiwan, so as to verify the system stability. According to the records of battery voltage, the maximum battery voltage within a day is around noon while the minimum is around midnight.

Assessment of landslide hazard zonation mapping in Kodaikanal, Tamil Nadu - India

Saranathan E.,1* Kannan M.1 and Victor Rajamanickam G.2

Landslide is one of the disasters which leads to large scale damage to properties and life. It frequently occurs in hilly regions like Himalaya, Western and Eastern Ghats. In Tamil Nadu, most of the landslides are often seen in Blue Mountains, Kodaikanal and Yercaud, occasionally in the other areas. Kodaikanal hills are facing two major problems viz. urbanization and environmental degradation. In this study, the landslide hazard zonation maps are prepared based on the causative factors of slope instability, namely lithology, structure, slope morphometry, relative relief, land use and land cover and hydrogeological conditions in facet wise by using BIS code: IS 14496 (Part-2) – 1998. As per BIS classification method in Kodaikanal area, the distribution pattern of Landslide Hazard Zonation (LHZ) indicates that in the total 102 facets, 21 facets come under high hazard category, 39 facets are present in medium hazards and remaining 42 facets come under range in low hazard.

A variation trend analysis of key controlling factos on slope dynamic response due to seismic action

Fangpeng Cui1*, Yueping Yin2 and Ruilin Hu3

Slopes’ dynamic response with different distances from the initial epicenter of the Wenchuan Earthquake due to single and combined action with regionality and spatial heterogeneity of Primary and Secondary waves is simulated by applying the Universal Distinct Element Code software. As a result, the key controlling factor and its variation trend with the increasing hypocentral distance of slope initial collapsing and sliding response due to seismic action are revealed. As far as the time consumed in the process from original slope to fractured is concerned, the slope under combined seismic action between P and S wave appears instability prior to the slope under single action of P wave. With the increasing hypocentral distance, the key controlling factor of the slope collapsing and sliding response varies from the combined seismic action between P and S wave to the single seismic action of P wave. As for the mechanical mechanism of slope instability, coupled action between vertical and horizontal ground acceleration results in the slope dynamic response with a variation trend of key action from the vertical acceleration to the horizontal one. Finally, the initial instability originates always at slope shoulder due to seismic action in relation with the peak ground acceleration amplification effect and the variation trend of the slope mechanical parameters on its fracturing.

Evaluation of Rationality of Emergency Shelters Distribution through Application 0f Landscape Index

He Yueyun1, Xue Xiongzhi1* and Zhou Liang1,2

Based upon analysis of spatial patterns along east-west and south-north extension shafts in Beijing City, China, the distribution rationality of emergency shelters was evaluated with gradient analysis as well as landscape index. The results showed that (1) the landscape index method can represent the overall distributional pattern of emergency shelters and its rationality; (2) emergency shelters in the city were generally highly fragmented, but had good connectivity and also had strong edge effects; (3) from the city center to the edges, emergency hedge place coverage did not vary with the change of distance between the shelter and the city center, while small patch quantity ratio, patch quantity, shape index, fragmentation degree and Euclidean nearest neighbor distance were subject to obvious gradient changes; (4) the main factor that influenced the coverage of emergency shelter and the distribution of patch areas and frequency was the distribution of large-scale patch of park nature. For cities with basically completed emergency hedge place system, under the limitation of area and coverage improvement, the rationality of space structure of the existing emergency shelters can be evaluated through the joint application of gradient analysis and landscape index. These parameters efficiently serve the adjustment and improvement of emergency shelters.

ORECOS: An open and rational emergency command organization structure under extreme natural disasters based on China’s national conditions

Liu Dan, Wang Hong-Wei *, Qi Chao and Wang Jian

The response to extreme natural disasters needs to focus on concentration and mobilization of all sorts of national forces and resources which requires a strong unified emergency command organization to command and coordinate. To this end, emergency command organization structure (ECOS) is essential in standardizing establishment of emergency command organization. Aiming at the problem that unclear responsibilities and incoherent relationships among members with various organization structures hinder rapid joint action and collaboration in emergency response process, an open and rational ECOS (ORECOS) based on organization theory is presented. A case study of ECOS of Three Gorges flood control is made to demonstrate and verify the applicability and rationality of ORECOS, taking Three Gorges suffered Yangtze River whole basin-wide flood in 2010 as background. The results show that the whole ORECOS based on matrix structure consists of three components: administrative emergency response system (AERS) based on bureaucratic structure, area commands (ACs) based on project team structure and consultation groups (CGs) based on task force structure. With a combination of rigidity, flexibility, hierarchy, authority, openness and contingency, ORECOS is more suited to China's national conditions and can create more effective emergency responses to extreme natural disasters.

Depositional slope break in shallow marine shelf setting and its control on regional forced regressive wedge systems tract

Liu Hao1*, WangYingmin2 and Xin Renchen1

During the deposition of the Miocene Zhujiang Formation, the HZ Sag in the Pearl River Mouth Basin, South China Sea, was a stably deposited shelf setting. A large-scale paleo-Pearl River water system was developed in the western part of the study area and provided abundant terrestrial deposits for the large-scale Pearl River delta. Depositional slope breaks with obviously varying gradients were formed along the delta front - prodelta belt due to their apparently differential deposition in these areas. The development of slope break in 3-D space is characterized by its inheritance, intermittent nature and cyclicity of time-spatial shifting. Large-scale depositional slope breaks mainly occurred in the Zhujiang Formation Middle Member. A case study on sequence PSQ6 has been carried out in this study. The depositional slope break of sequence PSQ6 is characterized by a certain developing scale of about 4 Km slope width, 20-60 m height difference and 80 Km transverse distribution range. Depositional slope breaks were mainly developed during the ending time of the depositional period of highstand systems tract delta of underlying sequence. A regional “ditch-trough” system was formed along the area between depositional slope break and carbonate buildup in the east of prodeltaic subfacies, thus provided a favorable paleogeomorphic setting for the deposition and preservation of PSQ6 forced regressive wedge systems tract(FRWST) and furthermore controlled the development of regional forced regressive wedge in shelf environment. It is quite different from the incised valley pattern which is developed above the shelf slope break and was described by Vail’s classical sequence stratigraphy. The forced regressive sandbodies are easily formed due to the “ditch-trough” paleogeomorphic setting in shelf environment. The progradational sandbodies directly cover the shallow marine mudstones of the underlying sequence highstand systems tract and are overlaid with the dark-color mudstones of transgressive and highstand systems tracts, thus a favorable source- reservoir- seal assemblage is formed and stratigraphic-lithologic hydrocarbon accumulations usually occur in these areas.

Drought Disaster Risk Assessment of the Yellow River Basin based on Historical Drought Information in GIS Environment

Pan Donghua 1 and Jia Huicong 2*

The Yellow River Basin is the cradle of the Chinese nation, but is also named as the crisis of the Chinese nation for having more sand, hanging River, easy to silt and frequent flooding and drought disasters. In this study, taking the 8 times typical historical drought situation in the Yellow River Basin as the main information source from 1639 to 1980 (the year of 1639, 1877, 1928, 1929, 1960, 1965, 1972 and 1980), transferring the historical drought information to the 100m×100m spatial grid in the river basin, the eight typical historical drought situation were overlaid by using spatial analysis module in GIS software. Risk analysis results were classified into five grades: very high risk area, high risk area, middle risk area, low risk areas and risk free area. Then the drought risk assessment distribution map of the Yellow River Basin based on historical drought information was got. The drought risk assessment of the Yellow River Basin can provide a scientific base for better guidance to the regional agricultural production and exploring regional resources and environment sustainable development model.

Graphics Processing Unit based searching the critical slip surface of slopes by the Vector Sum Analysis Method

Liu Shaobo*, Wang Chuanying and Han Zengqiang

Vector Sum Analysis Method (VSAM), with its clear physical and mechanical meaning in slope stability analysis, can be effectively applied to calculate the slope safety factor and to search the critical slip surface of a slope. In the current researches of VSAM, most people focus on the solutions or application in slope engineering without considering the computing performance. In recent years, Graphics Processing Unit (GPU) was quickly developed with its high performance of parallel computing. In this paper, VSAM based on GPU is put forward, the principles of GPU-based computing speedup are introduced and accelerated effects of two slope examples are tested under different computing scales. The results show that computing performance of GPU-based VSAM is significantly improved (the maximum speedup achieved is 31.07x); also, they demonstrate that an effective solution is provided for large-scale slope stability calculation.

Applying MORT to the Analysis of the Haiti’s Earthquake

Rafael Alvarado-Corona1* and Jaime Santos-Reyes2

The 2010 Haiti´s earthquake disaster occurred on Tuesday, 12 January 2010. The quake caused damage in Port-au-Prince, Jacmel and other settlements near the region. Throughout history, natural disasters have exerted a heavy toll of death and suffering and are increasing alarmingly worldwide. Given this, natural disasters present a great challenge to society today concerning how they are to be mitigated so as to produce an acceptable risk is a question which has come to the fore in dramatic ways recently. This study presents some preliminary results of the analysis of the Haiti’s earthquake that occurred in January 2010, by applying the Management Oversight Risk Tree (MORT) model. MORT may be regarded as a structured checklist in the form of a complex fault tree model that is intended to ensure that all aspects of an organization’s manag-ement are looked into when assessing the possible causes of an incident. The MORT model has been applied extensively to the analysis of accident/inc-idents that have occurred in industries, such as the oil and gas, nuclear, aviation etc. It may be argued that the model has the potentiality to be applied to the analysis of natural disasters such as earthquakes. It is hoped that by conducting such analysis, lessons can be learnt so that the impact of natural disasters like Haiti’s earthquake can be mitigated in the future.

Study of Residual Slope Mining and its Stability during ransition from Open Pit to Underground Mining

Nan Shiqing 1*, Guo Xianzhang 2 and Zhang Juanxia 2

It is fundamental to adopt a holistic approach during the smooth transition from open pit to underground mining to ensure a successful mining operation. One of the key problems for the smooth transition is to realize output connection and emphasis of the work task focus on maintaining the stable ore output in the mine. In this study, some effective measures which ensure the stable ore output during the transition period were put forward with a case in mining project. Numerical simulation analysis and calculating method was an effective way to study the slope stability; the slope of goaf should be real-time monitored to forecast the landslide of the geological hazard. The investigation has some reference significance for transition mining from open pit to underground mine

Researsch in Analytical Method for Halogenated Hydrocarbon Degradation Materials in Groundwater - Methane, Ethylene an Ethane

Yang Jin,* Ou Dongni, Cai June, Yang Lynn and Xue James

The measurement of halogenated hydrocarbon degradation materials in groundwater is important to evaluate and remediate the contaminated aquifer. The research has established an analytical method for monitoring dissolved gases methane, ethylene and ethane in groundwater by a GC headspace equilibration technique which had been optimized the equilibration time. This method has been applied in monitoring groundwater samples in the contaminated sites. The relative standard deviations of target compounds in seven spiked water samples are in the range of 2.15 to 3.66 % and the recoveries are in the range of 92 to 97 %. The method detection limit is 5 μg/L. The method provides the advantages of low detection limit, high sensitivity, high accuracy and precision, simple operation and is suitable for ground water investigation in a large scale.

Stability evaluation indexes of deep stope pillar and roadway surrounding rock

Yu Weijian 1*, Zhai Shuhai 2 and Gao Qian 2

Because pillars usually bear the long time effect of ground pressure, there are potential dangerous of instability, so key problem is how to evaluate stability of pillars. Based on force and deformation characteristics of pillars in deep stope and in combination with numerical analysis method, we proposed three stability evaluation indexes CSH, SSH and FRH of horizontal pillars and four stability evaluation indexes CSV, FRV, CSR and DCR of vertical pillars and roadways. According to twenty-seven calculation schemes of thirteen factors and three levels, we adopted the FLAC program and the range theory to analyze impact factors and superior-inferior mining projects. The optimal mining project of horizontal pillars based on the stability evaluation index FRH was applied in Jinchuan Mine; monitoring results of 320 days show that the max convergence values of two sides is 31.13 mm, convergence rates less than 0.1 mm/d and roadway surrounding rock tend to be stable.

Stability Evaluation of Rock Block in Jointed Rock Masses considering Earthquake Impacts

Zhang Yuting *, Ding Xiuli, Huang Shuling and Lu Bo

The stability of rock blocks is a key issue for engineering projects in jointed rock masses. The southwestern region of China is high seismic intensity area. The stability of blocks under earthquake impact is crucial for hydropower plants during operation period. To address this issue, this study puts forward a method for evaluating block stability considering earthquake impacts. The originality of this method is to apply sophisticated Finite Element Method (FEM) to analyze block stability. First, block identification algorithm using finite element mesh is introduced. Then, wave filed method is used to simulate earthquake impact. Also, several FEM analysis techniques, such as its computation procedures and numerical algorithms for geological discontinuities, are given. Vector analysis method is used to evaluate block stability. The way to include FEM analysis results into block stability evaluation is given. A case study is done to demonstrate the effectiveness of the proposed method. As FEM considers the effects of tunnel excavation, earthquake impacts and anchor reinforcement, block stability conditions under different load combinations can be quantified. It is revealed that rock excavation has the most significant effects on block stability. Earthquake will undermine block stability, and proper intensity of anchor support measures can obtain satisfactory reinforcement effect to guarantee the stability of blocks.

Study of Fractal Characteristics on Micropores and Microcracks in Rock before Rock Engineering Disasters

Li Liu and Quian- Cao Shui

Rock microscopic characteristics will change before rock engineering disasters. In this study, the microstructure of rock and cell of rock are researched by means of SEM. Stretches of rock microcrack are analyzed. The fractal characteristics are calculated by dissipated energy consumed by microstructure fracture. The form and direction of crack stretch in rock are analyzed by way of loading. The regularity of damage evolution in rock is explained. The generation, distribution and elongation procedure of rock crack are analyzed by the use of fractal geometry and micro-thought methods. The characteristics of micro-damages and evolution of rock cracks are explored by means of experimental observation and calculation of the dissipative force. The analysis shows that the speed, direction and quantity of microcrack stretch is dependent mainly on the component, combination of mineral, combinatorial density, quantity and direction of load, state of stress and its ratio, when the crack is expanding from micropore to macrograph fissure