Response of three Athens metro underground structures in the 1999 Parnitha earthquake

The M_s 5.9 earthquake of 1999 produced valuable records in three underground structures, as follows: (a) in the just completed cut-and-cover station of Sepolia two accelerographs recorded the free-field and the station-base motion; (b) in the still under-construction tunnelled station of Monastiraki an accelerograph recorded the ground surface motion, and (c) in the nearby Kerameikos station, abandoned for non-technical reasons, the temporary prestressed-anchor piled (PAP) wall was still in place and produced a record of total seismic displacement at its top. Directly or indirectly utilising these records, the article outlines the results of numerical analyses aimed at ‘recovering’ the complete seismic response of the three underground structures. Particular emphasis is given to Sepolia station, where the developed accelerations (with PGA of about 0.17 g at the station base and 0.43 g at the station roof) are shown to have been almost exactly equal to the design accelerations according to the seismic code under the assumption that the station responds as an aboveground structure. The successful performance of the two temporary structures, in Monastiraki and Kerameikos (which had been designed against minimal acceleration levels but experienced ground-surface high-frequency accelerations of the order of 0.50 g) is explained through dynamic response analyses.     

Industrial sources of CO2 emissions in Poland in the light of underground storage possibilities

Industrial sectors responsible for large part of CO₂ emissions in Poland are characterized from the point of view of possibilities of sequestration of this gas by underground storage. On the basis of official statistics and data obtained from local administration and individual plants, attempt was made to evaluate the magnitude of emissions from selected categories, sub-categories and sectors of the industry (in accordance with methodology of IPCC), concentration of CO₂ in combustion gases and those emitted by industry, and to identify major point sources of emission of this gas in Poland. A special attention was paid to those sectors of industry that may be the first to act as a source of carbon dioxide for sequestration by underground storage in the nearest future. To cite this article: R. Tarkowski, C. R. Geoscience 337 (2005).     

建筑物下爆破地震效应的研究——"爆破安全规程"的应用与修正

叙述了大姚铜矿的大药量爆破振动效应观测,研究了在建筑物下的爆破施工中,如何确保建筑物安保证安全生产最大用药量的问题,结合“爆破安全规程”药量指数m的应用与修正,从而得出正在对爆破上方的建筑物地面爆破振动动加速度a,速度v随爆心距地面投影r与爆心深度h之比值（r/h)的衰减变化规律;发现临近正对爆心的地面振动有强心现象,并定义它为“极震”效应;定义“极震”效应系数N为正对爆心实测加速度a或速度v与用振动衰减普适式求得值a'或v'之比（N＝a/a',或N=v/v'）。经多年的安全生产证明,采用振动衰减普适式（药量指娄m=1/3)和“极震”效应系数修正法,效果良好,获得生产最佳用药量,民房安全率达98％左右。     

城市地下空间开发利用情况及环境地质问题分析

地下空间具有恒温、恒湿、隔热、遮光、气密、隐蔽、安全等优点,地下构筑物具有良好的抗震性、稳定性、隐蔽性、防护性、隔音性等特性。介绍了城市对地下空间的利用情况与发展趋势,以及城市地下空间资源开发利用中的环境地质问题或地质灾害。     

Spatial predictions of geological rock mass properties based on in-situ interpretations of multi-dimensional seismic data

The article presents a statistical approach to characterize and predict engineering geological conditions in the up to 2000 m deep Faido tunnel and Gotthard base tunnel in Switzerland. Seismic investigations were conducted to improve the technology of interpreting seismic tomographic images. Overall, the goal of this study was to predict spacial maps of geological rock mass properties, such as, uniaxial compressive strength or total fracture spacing, by using up to six seismic features in combination, e.g., compression-wave and shear-wave velocities and dynamic Poisson's ratio. Self-Organizing Mapping (SOM), an artificial intelligent method, was used for the purposes of interpreting multi-dimensional geophysical attributes derived from seismic profiles of tomographic images along tunnel sidewalls. The SOM-method was applied in the Faido tunnel to delineate complex physical relations between the geological and seismic parameters. Then, the method was applied to predict geological properties around a segment of the Gotthard base tunnel with unknown geological–geotechnical conditions. The results illuminate that correlation analyses (pairwise parameter classification) are substantially less powerful than the SOM-method (multi-parameter classification) in order to interpret geological features from seismic in-situ data. Moreover, predicted spatial distributions of the total fracture spacing and the uniaxial compressive strength, for example, corresponded well with drill core and tunnel mapping results. The SOM-approach was a helpful tool for practitioners in predicting zones of instabilities and geological complexity during underground excavation processes of the Gotthard base tunnel. It is suggested to use such an interpretation method as decision support for purposes of sub/surface exploration and long-term geophysical monitoring of large-scale geoengineering projects, such as, disposals of nuclear waste and greenhouse gases or geopower plants for renewable energy (geothermal, biosoils).     

降水与提取地下水位中的地震孕育信息

有许多因素会引起地下水位变化,如地震的孕育过程、降水、固体潮等。其中我们感兴趣的是地震孕育信息。消除各干扰因素的影响是挖掘隐藏在地下水位中地震孕育信息的一种有效途径。本文提供了两种不同的消除降水因素影响的方法,通过相关分析来比较两种方法的效果,并在此基础上建立了描述地震活动水平的Logistic回归模型。     

Development and application of reservoir models and artificial neural networks for optimizing ventilation air requirements in development mining of coal seams

In longwall development mining of coal seams, planning, optimizing and providing adequate ventilation are very important steps to eliminate the accumulation of explosive methane–air mixtures in the working environment. Mine operators usually try to supply maximum ventilation air based on the capacity of the system and the predicted need underground. This approach is neither economical nor safer as ventilation capacity may decrease in time depending on various mining and coalbed parameters. Thus, it is important to develop better engineered approaches to optimize mine ventilation effectiveness and, therefore, to ensure a safer work environment.This study presents an approach using coalbed methane reservoir modeling and an artificial neural network (ANN) design for prediction and optimization of methane inflows and ventilation air requirements to maintain methane concentrations below statutory limits. A coalbed reservoir model of a three-entry development section, which is typical of Pittsburgh Coalbed mines in the Southwestern Pennsylvania section of Northern Appalachian Basin, was developed taking into account the presence and absence of shielding boreholes around the entries against methane inflow. In the model, grids were dynamically controlled to simulate the advance of mining for parametric simulations.Development and application of artificial neural networks as an optimization tool for ventilation requirements are introduced. Model predictions are used to develop, train, and test artificial neural networks to optimize ventilation requirements. The sensitivity and applications of proposed networks for predicting simulator data are presented and discussed. Results show that reservoir simulations and integrated ANN models can be practical and powerful tools for predicting methane emissions and optimization of ventilation air requirements.     

城市地下管线数据的质量控制探讨

本文对城市地下管线数据的质量控制作了具体的探讨,并且结合佛山市的具体情况,对其城市地下管线数据做了具体的质量控制,取得了比较满意的效果。     

Crustal structure of Atlantic fracture zones–II. The Vema fracture zone and transverse ridge

Summary. The crustal structure beneath the Vema fracture zone and its flanking transverse ridge was determined from seismic refraction profiles along the fracture zone valley and across the ridge. Relatively normal oceanic crust, but with an upwarped seismic Moho, was found under the transverse ridge. We suggest that the transverse ridge represents a portion of tectonically uplifted crust without a major root or zone of serpentinite diapirism beneath it. A region of anomalous crust associated with the fracture zone itself extends about 20 km to either side of the central fault, gradually decreasing in thickness as the fracture zone is approached. There is evidence to suggest that the thinnest crust is found beneath the edges of the 20 km wide fracture zone valley. Under the fracture zone valley the crust is generally thinner than normal oceanic crust and is also highly anomalous in its velocity structure. Seismic layer 3 is absent, and the seismic velocities are lower than normal. The absence of layer 3 indicates that normal magmatic accretionary processes are considerably modified in the vicinity of the transform fault. The low velocities are probably caused by the accumulation of rubble and talus and by the extensive faulting and fracturing associated with the transform fault. This same fracturing allows water to penetrate through the crust, and the apparently somewhat thicker crust beneath the central part of the fracture zone valley may be explained by the resultant serpentinization having depressed the seismic Moho below its original depth.