地面地震层析技术在金属矿勘查中的试验研究

由于金属矿区地质构造的复杂性和复杂的地表条件, 适合于探测层状介质的地震反射方法技术在金属矿勘查中的应用受到了限制。为提高地震记录的横向分辨率, 探测复杂的地质构造及隐伏岩体等, 需研究相应的地震方法技术, 地面地震层析技术在金属矿勘查中的试验研究就是为解决上述问题而开展的。本文就非线性地面地震层析技术的基本原理进行了阐述, 并就该方法在金属矿勘查中的试验效果进行了讨论。     

利用Java-X3D实现地震层位三维可视化

地震层位三维可视化可以提供形象化的地震层位三维特征,便于地震资料的后期解释.在叙述地震层位三维可视化技术原理、目标、方法的基础上,尝试利用Java-X3D技术实现地震层位三维可视化,并利用实际坐标数据,实现了在Internet上跨平台的地震层位及地质构造三维可视化模拟,取得了良好的效果.     

HD-4002型综合测井仪

HD 4002型综合测井仪是核工业北京地质研究院于1998年开始研制的, 其目标是为铀矿地质系统提供适合砂岩型铀矿勘查的轻便型数字测井仪, 满足测井生产的需要。该仪器于2001 年3月通过部级鉴定, 2002至2003年投入海拉尔盆地铀矿勘查测井试生产。本文介绍了仪器的用途、功能及特点、性能指标, 简要说明了各部分的工作原理。     

C1相干算法及其在三维地震资料处理解释中的应用

C1相干算法是计算每道的横测线和相邻纵测线的互相关，依据相干值来判断地层和岩性的横向不均匀性。根据互相关原理，提出了相干体算法中二维和三维C1算法的内容及其具体实现。通过对实际三维地震资料的处理，结合已知地质资料，证明C1相干技术在三维地震资料的断层解释方面有着明显的效果。     

禹州煤田泉店井田构造特征及对其二1煤层的影响

对泉店井田的地质构造进行了分析研究,阐明了断层及褶曲的分布,探讨了井田的构造演化,分析了构造特别是断层对二1煤层的影响,为今后煤矿开发生产提供了可靠的地质依据.     

煤矿采区三维地震资料解释中的切片技术及其应用

长期以来,煤矿采区三维地震勘探资料解释的工作流程与二维地震勘探基本相同,三维地震资料相对二维地震资料所具有的许多解释方面的优越性未能有效发挥出来,人机联作的过程相对简单.在三维地震勘探获取的三维数据体基础上,可做进一步的运算和分析,提取速度、振幅、频率、相位等相关信息,并利用等时切片、层拉平切片、断层切片、面块切片、方差体、相干体等各种技术,有效解释小构造、小褶曲及岩性方面的信息.     

A mathematical hysteretic model for elastomeric isolation bearings

An analytical model for high damping elastomeric isolation bearings is presented in this paper. The model is used to describe mathematically the damping force and restoring force of the rubber material and bearing. Ten parameters to be identified from cyclic loading tests are included in the model. The sensitivity of the ten parameters in affecting the model is examined. These ten parameters are functions of a number of influence factors on the elastomer such as the rubber compound, Mullins effect, scragging effect, frequency, temperature and axial load. In this study, however, only the Mullins effect, scragging effect, frequency and temperature are investigated. Both material tests and shaking table tests were performed to validate the proposed model. Based on the comparison between the experimental and the analytical results, it is found that the proposed analytical model is capable of predicting the shear force–displacement hysteresis very accurately for both rubber material and bearing under cyclic loading reversals. The seismic response time histories of the bearing can also be captured, using the proposed analytical model, with a practically acceptable precision. Copyright © 2002 John Wiley & Sons, Ltd.     

Comparative response analysis of conventional and innovative seismic protection strategies

The paper presents a numerical investigation aimed at evaluating the improvements achievable through devices for passive seismic protection of buildings based on the use of shape memory alloys (SMA) in place of conventional steel or rubber devices. To get some generality in the results, different resisting reinforced concrete plane frames were analysed, either protected or not. ‘New’ and ‘existing’ buildings were considered depending on whether seismic provisions are adopted in the building design or not. Base isolation and energy dissipation were equally addressed for both conventional and innovative SMA‐based devices. Fragility analyses were performed using specific damage measures to account for comparisons among different damage types; the results were then used to estimate quantitatively the effectiveness of the various protection systems. More specifically, the assessment involved a direct comparison of the damage reduction provided by each protection system with respect to the severe degradation experienced by the corresponding non‐protected frame. Structural damage, non‐structural damage and damage to contents were used on purpose and included in a subsequent phase of cost analysis to evaluate the expected gains also in terms of economic benefits and life loss prevention. The results indicate that base isolation, when applicable, provides higher degrees of safety than energy dissipation does; moreover, the use of SMA‐based devices generally brings about better performances, also in consideration of the reduced functional and maintenance requirements. Copyright © 2002 John Wiley & Sons, Ltd.     

Seismic response of self‐centring hysteretic SDOF systems

The seismic response of single‐degree‐of‐freedom (SDOF) systems incorporating flag‐shaped hysteretic structural behaviour, with self‐centring capability, is investigated numerically. For a SDOF system with a given initial period and strength level, the flag‐shaped hysteretic behaviour is fully defined by a post‐yielding stiffness parameter and an energy‐dissipation parameter. A comprehensive parametric study was conducted to determine the influence of these parameters on SDOF structural response, in terms of displacement ductility, absolute acceleration and absorbed energy. This parametric study was conducted using an ensemble of 20 historical earthquake records corresponding to ordinary ground motions having a probability of exceedence of 10% in 50 years, in California. The responses of the flag‐shaped hysteretic SDOF systems are compared against the responses of similar bilinear elasto‐plastic hysteretic SDOF systems. In this study the elasto‐plastic hysteretic SDOF systems are assigned parameters representative of steel moment resisting frames (MRFs) with post‐Northridge welded beam‐to‐column connections. In turn, the flag‐shaped hysteretic SDOF systems are representative of steel MRFs with newly proposed post‐tensioned energy‐dissipating connections. Building structures with initial periods ranging from 0.1 to 2.0s and having various strength levels are considered. It is shown that a flag‐shaped hysteretic SDOF system of equal or lesser strength can always be found to match or better the response of an elasto‐plastic hysteretic SDOF system in terms of displacement ductility and without incurring any residual drift from the seismic event. Copyright © 2002 John Wiley & Sons, Ltd.     

A recursive decomposition algorithm for network seismic reliability evaluation

A new probabilistic analytical approach to evaluate seismic system reliability of large lifeline systems is presented in this paper. The algorithm takes the shortest path from the source to the terminal of a node weight or edge weight network as decomposition policy, using the Boolean laws of set operation and probabilistic operation principal, a recursive decomposition process then could be constructed. For a general weight network, the modified Torrieri method (NTR/T method) is introduced to combine with the suggested algorithm. Therefore, the recursive decomposition algorithm may be applied to evaluate the seismic reliability of general lifeline systems. A series of case studies, including a practical district electric power network system and a large urban water supply system, show that the suggested algorithm supplies a useful probabilistic analysis means for the seismic reliability evaluation of large lifeline systems. Copyright © 2002 John Wiley & Sons, Ltd.