Improved control algorithm for real‐time substructure testing

Real‐time substructure testing is a novel method of testing structures under dynamic loading. The complete structure is separated into two substructures, one of which is tested physically at large scale and in real time, so that time‐dependent non‐linear behaviour of the substructure is realistically represented. The second substructure represents the surrounding structure, which is modelled numerically. In the current formulation this numerical substructure is assumed to remain linear. The two substructures interact in real‐time so that the response of the complete structure, incorporating the non‐linear behaviour of the physical substructure, is accurately represented. This paper presents several improvements to the linear numerical modelling of substructures for use in explicit time‐stepping routines for real‐time substructure testing. An extrapolation of a first‐order‐hold discretization is used which increases the accuracy of the numerical model over more direct explicit methods. Additionally, an integral form of the equation of motion is used in order to reduce the effects of noise and to take into account variations of the input over a time‐step. In order to take advantage of this integral form, interpolation of the model output is performed in order to smooth the output. The improvements are demonstrated using a series of substructure tests on a simple portal frame. While the testing approach is suitable for cases in which the physical substructure behaves non‐linearly, the results presented here are for fully linear systems. This enables comparisons to be made with analytical solutions, as well as with the results of tests based on the central difference method. Copyright © 2001 John Wiley & Sons, Ltd.     

In situ and laboratory investigations of fluid flow through an argillaceous formation at different scales of space and time, Tournemire tunnel, southern France

In the context of a research and development program on waste disposal, an experimental site (Tournemire tunnel, Aveyron, France) was selected by the French Institute for Nuclear Protection and Safety (IPSN) in order to undertake studies on potential fluid flow at different scales of space and time within a 250-m-thick argillaceous formation. The argillite has a low natural water content (~3–5%) and very low radii access porosity. Diffusion (tritiated water) coefficients (1×10^–12 to 2×10^–11 m²/s) and hydraulic conductivities derived from different types of laboratory tests (10^–14 to 10^–13 m/s) are characteristics of a very low-permeable rock. In situ hydraulic tests (including long-term hydraulic-head measurements) were used to obtain values for hydraulic head and hydraulic conductivity at a scale of 1–10 m (10^–13 to 10^–11 m/s). Despite uncertainties on these data (due to a scale factor, presence of fissures, and possible artefacts due to hydro-chemo-mechanical coupling), it is expected that fluid flow is essentially governed by diffusion processes. Identification of possible natural flows at larger scales of time and space was investigated using natural isotopic tracers from interstitial fluids. Modelling, based on the deuterium profile along the clay formation and assuming pure diffusion processes, provides estimations of possible flow times. However, lack of knowledge concerning the past geological evolution of the site and the possible role of a fracture network do not permit reduction of uncertainties on these estimations at this stage. Electronic Publication     

伊朗SK500m探层试验孔钻探工艺

在伊朗ＳＫ５００ｍ探层钻孔施工中，采用ＰＨＰ－ＣＭＣ凝胶低固相泥浆顶漏钻进覆盖层，以清水和金刚石单动双管取心钻具钻进试验段，进行压水试验后，一周 用ＰＨＰ－ＣＭＣ凝胶无固相冲洗液护壁钻进至终孔，并利用泵压注浆水加固孔壁，较好地解决了防斜，堵漏止涌以及取心困难等技术问题     

地质实验测试科技八五进展及九五发展计划设想

从岩矿测试、岩石矿物学研究、选冶技术、非金属矿开发利用、标准物质与标准方法、分析仪器的研制与技术改造等专业例举了代表性成果，对八五期间地质实验测试领域技术主要进展作了回顾；并依据地质矿业生产与发展的客观实陆，提出了九五期间地质实验测试技术发展计划设想，其重点是加强基础研究，发展高新技术、增强经济效益，促进地质科学研究和地质的矿取得重大突破以及地矿产业的迅速发展。     

菲尔德斯形变监测网质量分析

从数理统计角度出发，对西南极菲尔德斯形变监测网进行综合质量评估。文中主要讨论了形变监测网粗差检验，形变监测网的可靠性及可监测性。同时结合菲尔德斯形变监测网实测数据进行分析。本文认为该形变监测网有利于监测菲尔德斯海峡断层的剪切运动。     

钻井岩心三个力学参数的测试

介绍了钻井岩心机械特性的测试方法－－三轴应力试验，通过对两地区部分岩心的测试，得出了岩石泊松比，杨氏弹性模量和抗拉强度等岩石力学参数，数据分析表明，岩石泊松比和杨氏弹性模量都随围压增加而增大，并给出了经验关系式。     

浅析声测岩石试件尺寸的确定

本文从声发射的辐射、散射理论出发，讨论了室内岩石试件在满足有关尺寸的情况下可视为无限体，从而对各单位的有关规定进行了评价，为今后室内岩石试件的声测从理论上找出了标准尺寸，统一了认识，以便更好地服务于工程建设。     

Simple swept-sine analyzer for excitation and measurement of dynamic response in ocean structures

We present the design of a simple, low cost swept-sine analyzer. Based on direct digital synthesis, the analyzer can generate high purity tones with a linear resolution of 0.000931 Hz up to 1 MHz. Details of the circuit are discussed, and the performance of the system is demonstrated by a simple application to the dynamical characterization of cracked cantilever beams. It is felt that the device may find application in the design, construction and monitoring of structural systems such as offshore platforms and other marine structures.