Development and application of a GIS-based tool for earthquake-induced hazard prediction

An integrated GIS-based tool (GTIS) was constructed to estimate site effects related to the earthquake hazards in the Gyeongju area of Korea. To build the GTIS for the study area, intensive site investigations and geotechnical data collections were performed and a walk-over site survey was additionally carried out to acquire surface geo-knowledge data in accordance with the procedure developed to build the GTIS. For practical applications of the GTIS used to estimate the site effects associated with the amplification of ground motion, seismic microzoning maps of the characteristic site period and the mean shear wave velocity to a depth of 30 m were created and presented as a regional synthetic strategy addressing earthquake-induced hazards. Additionally, based on one-dimensional site response analyses, various seismic microzoning maps for short- and mid-period amplification potentials were created for the study area. Case studies of seismic microzonations in the Gyeongju area verified the usefulness of the GTIS for predicting seismic hazards in the region.     

Screening and ranking framework for geologic CO<Subscript>2</Subscript> storage site selection on the basis of health,safety, and environmental risk

A screening and ranking framework (SRF) has been developed to evaluate potential geologic carbon dioxide (CO₂) storage sites on the basis of health, safety, and environmental (HSE) risk arising from CO₂ leakage. The approach is based on the assumption that CO₂ leakage risk is dependent on three basic characteristics of a geologic CO₂ storage site: (1) the potential for primary containment by the target formation; (2) the potential for secondary containment if the primary formation leaks; and (3) the potential for attenuation and dispersion of leaking CO₂ if the primary formation leaks and secondary containment fails. The framework is implemented in a spreadsheet in which users enter numerical scores representing expert opinions or published information along with estimates of uncertainty. Applications to three sites in California demonstrate the approach. Refinements and extensions are possible through the use of more detailed data or model results in place of property proxies.     

Nonlinear Analysis of Local Site Effects on Seismic Ground Response in the Bam Earthquake

The influence of local geologic and soil conditions on the intensity of ground shaking is addressed in this study. The amplification of the ground motion due to local site effects resulted in severe damage to dwellings in the Bam area during the 2003 Bam Earthquake. A unique set of strong motion acceleration recordings was obtained at the Bam accelerograph station. Although the highest peak ground acceleration recorded was the vertical component (nearly 1 g), the longitudinal component (fault-parallel motion) clearly had the largest maximum velocity as well as maximum ground displacement. Subsurface geotechnical and geophysical (down-hole) data in two different sites have been obtained and used to estimate the local site condition on earthquake ground motion in the area. The ground response analyses have been conducted considering the nonlinear behavior of the soil deposits using both equivalent linear and nonlinear approaches. The fully nonlinear method embodied in FLAC was used to evaluate the nonlinear soil properties on earthquake wave propagation through the soil layer, and compare with the response from the equivalent linear approach. It is shown that thick alluvium deposits amplified the ground motion and resulted in significant damage in residential buildings in the earthquake stricken region. The comparison of results indicated similar response spectra of the motions for both equivalent and nonlinear analyses, showing peaks in the period range of 0.3–1.5 s. However, the amplification levels of nonlinear analysis were less than the equivalent linear method especially in long periods. The observed response spectra are shown to be above the NEHRP building code design requirements, especially at high frequencies.     

Filtration and Clogging Behavior of Geotextiles with Roorkee Soils

Geotextile filters are rapidly replacing graded granular filters as the standard of practice in geotechnical design. The objective of the present study is to predict the behavior of the geotextile filter for the locally (Roorkee—India) available soils using three different geotextiles (two nonwoven and one woven). Nonwoven geotextiles are commonly used in filtration applications. This paper evaluates the long-term performance of two needle-punched nonwoven geotextiles and one woven geotextile. Filtration tests on soil–geotextile filter systems were conducted in the laboratory in order to evaluate the filtration and clogging behavior. Laboratory test program, include evaluation of performance of two different nonwoven and one woven geotextile filters in combination with locally available Solani River Sand and Clayey Soil. The paper describes the concept and details of the Fine Fraction Filtration (F³) test and presents data on three different geotextiles, which were evaluated using three different soil types. It is deduced that in all filtration applications, the non-woven geotextile would perform better than the woven geotextile.     

南海南部粉红色 Globigerinoides ruber 冰期旋回及影响因素

对南海南部ODP1143站氧同位素11-5e期大约2ka分辨率的粉红色Globigerinoides ruber进行分析,发现其冰期／间冰期旋回与代表全球冰量的底栖有孔虫氧同位素(δ^18O)的变化相反,即在间冰期时含量低,而冰期时高,与其他海区的记录相反。海水表层温度和温跃层深度转换函数结果以及碎壳率的变化显示,在一定的温度背景下,温跃层深度的变化可能是控制粉红色G．ruber冰期旋回的主要因素,而这段时期南海南部溶解作用的影响则不明显。     

北京市地铁暗挖施工沉降控制探讨

仅以北京市地铁4#线张自忠车站主体暗挖施工的沉降监控项目为研究背景,对穿越城市主干道的车站结构暗挖施工进行连续性的沉降变形监测;从地下构筑物暗挖施工的工序变化与地表沉降的关系进行试验研究.在预测基础上对获取的数据进行多层次的统计与分析,以研究其变形规律与稳定性,实现了信息化施工.     

Alteration, evaluation and use of extremaduran granite residues

The necessity of eliminating debris from a granite quarry has awakened an interest in applications of by-products, called “marginal arids”, in different fields, like construction and foundations for roadways, restoration, material for the manufacture of artificial rocks, and artesian products etc. Conclusions obtained from the results of tests carried out by X-ray diffraction of granite quarry by-products in Extremadura, Spain, submitted to different treatments, are established. Test pieces from two quarries are analyzed and compared generally and specifically, for commercial use. Finally, conclusions relating to essays in test pieces and mineral dynamics of marginal arid granite are exposed.     

某既有建筑物改造工程地基加固质量的综合检测

随着既有建筑物的增层改造工程的发展和技术的日益成熟 ,为了提高原有建筑物地基土强度和变形能力 ,对其基础加固处理也愈加频繁。如何准确有效地评价其地基加固质量及其空间变化的均匀性是关系此类工程安全可靠的重要保证。本文以某一工程为例 ,讨论既有建筑物增层改造工程的地基加固质量的检测和综合评价方法。该建筑物建于 5 0年代 ,原设计为 5层 ,现增层为 6层 ,采用高压注浆方法进行地基加固处理.     

ODP 1144站钻孔沉积物中微玻璃陨石的元素地球化学特征

利用电子探针和激光探针等离子体质谱方法分析了取自南海北部的ODP1144钻孔沉积物中的微玻璃陨石和取自邻近的广东省湛江和吴川玻璃陨石的主元素和微量元素组成。结果显示，这些微玻璃陨石属于亚洲-澳大利亚散落区的普通微玻璃陨石。从成分上看，这些微玻璃陨石存在两种不同的类型，其中的绝大部分Al2O3含量在19.0%以上，属于高Al类型，相应的难熔微量元素含量也比较高；个别微玻璃陨石Al2O3含量（13.0%)和难熔微量元素含量较低，微量元素含量和特征比值都与邻近的广东省湛江和吴川的玻璃陨石相近。元素地球化学特征意味着，这些微玻璃陨石来源于同一靶源区，但靶区的物质组成并不均一。     

Horizontal and vertical components of earthquake ground motions at liquefiable sites

Field observations on ground motions from recent earthquakes imply that current knowledge is limited with regard to relating vertical and horizontal motions at liquefiable sites. This paper describes a study with the purpose of clarifying this emerging issue to some extent. A series of numerical analyses is carried out on a liquefiable soil deposit with a verified, fully coupled, nonlinear procedure. It is shown that the transformation of vertical motions in the deposit differs considerably from the transformation of horizontal motions. Both the amplitude and frequency content of the horizontal motions are strongly dependent on the shaking level or the associated nonlinear soil behavior. The transfer function for vertical motions is however likely to be independent of the intensity of input motions; no reduction in the amplitude occurs even in the case of strong shaking. The results are shown to be in consistence with the laboratory observations on shaking table tests and recent field observations that less nonlinearity exists for vertical motions. It is also shown that the possibility exists for using information on spectral ratios between the horizontal and vertical surface motions to quickly identify in situ soil behavior and liquefaction that are not readily covered by conventional field or laboratory experimentation procedures.