Modelling of Progressive and Instantaneous Failures of Foliated Rock Slopes

Summary Mechanisms of flexural toppling failure of slopes in foliated rock masses are investigated both experimentally by testing small scaled models in a centrifuge and theoretically by using a limiting equilibrium model and a finite element model based on the Cosserat theory. Both theoretical models include bending moments of rock layers in their formulation. Two main failure mechanisms are observed: (1) instantaneous failure involving a large volume of failed material and (2) progressive failure where the fracture initially localises near the toe region and then progresses further into the rock mass with increasing load. These two mechanisms of slope failure are observed to be controlled by the magnitude of the joint friction angle. The joint friction angles of about 20° and above are most likely to cause instantaneous failure while the lesser friction angles result in a progressive failure. Joint cohesion is not found to have a similar effect on the failure mechanisms, provided that it is low enough to allow sliding between the rock layers – a prerequisite for flexural toppling.     

Simulation of rain-bearing summer monsoon systems along the west coast of India by use of ARMEX re-analysis

Re-analysis, using surface, upper-air, and satellite observations specially collected during the Arabian Sea Monsoon Experiment-I (ARMEX-I), has been performed with a global data assimilation system at T-80/L18 resolution. Re-analysis was performed for the entire ARMEX-I period (15th June–16th August 2002). In this paper we discuss the results based on re-analysis and subsequent forecasts for two successive intensive observation periods associated with heavy rainfall along the west coast of India during 2–12 August, 2002. Results indicate that the re-analysed fields can bring out better synoptic features, for example troughs along the west coast and mid tropospheric circulation over the Arabian Sea. Simulated rainfall distribution using re-analysis as initial condition also matches observed rainfall better than data from the initial analysis.     

ISEE: Internet‐based Simulation for Earthquake Engineering—Part I: Database approach

An Internet‐based framework, named Internet‐based Simulation for Earthquake Engineering (ISEE) was developed to facilitate collaborative earthquake engineering experiments performed by multiple laboratories in a network environment. One of the approaches in the ISEE framework, named Database Approach, offers an easy way to perform multi‐site networked collaborative pseudo‐dynamic experiments. The Database Approach uses the Structured Query Language (SQL), a common and standardized computer language used in database management systems, for inter‐laboratory communications. Using the SQL protocol, it is easy to monitor the experiments' progress, access the data, as well as develop additional programs to expand the functions for a networked experiment. This approach offers consistency and durability of selected experimental data both during and after experiments. Two networked pseudo‐dynamic experiments were conducted to demonstrate the feasibility and expansibility of the Database Approach in ISEE. Copyright © 2007 John Wiley & Sons, Ltd.     

Experimental remolding on the caprock’s 3D strain field of the Indosinian-Yanshanian epoch in Tongling deposit concentrating area

~~Experimental remolding on the caprock’s 3D strain field of the Indosinian-Yanshanian epoch in Tongling deposit concentrating area1.Chang,Y.F.,Liu,X.P.,Wu,Y.C,The Cu,Fe Metallogenic Belt in the Middle-Lower Reaches of Yangtze River(in Chinese with English abstract),Beijing:Geological Publishing House,1991,1-379. 2.Yin,H.F.,Wu,S.B.,Du,Y.S.,South China is the part of multi-islands and multi-oceans system of Tethys,Earth Sciences(in Chinese),1999,24(1):1-12. 3.Wu,G G,Zha…     

Prediction of in-situ block size distributions with reference to armourstone for breakwaters

Understanding a quarry in terms of its potential for breakwater construction materials presents a special challenge for the engineering geologist. Unlike blasting in aggregates and mining operations, optimisation of the extraction process has a focus on the potential for production of large blocks for armourstone. These blocks weighing many tonnes are used for cover layers to resist wave action. The quarry-run is used for breakwater core. If the quarry has been developed as a source of materials dedicated to a breakwater construction project, the success of the project depends greatly on the blasting and production of rock sizes that are required and the avoidance of leaving a massive quantity of unused materials behind in the quarry after project completion. Prediction of in-situ block sizes such as from joint spacing data, provides the most critical input for the prediction of the blast pile block size distribution (BBSD), which in turn is a vital early design input if the constructed breakwater is to be economical as well as effective.This paper is part of a series of papers that introduces the coastal engineering motivation for this work on engineering geology, giving reasons why the prediction of the fragmentation curve of the blast products in a dedicated quarry is of such economic importance for breakwater projects. The first step towards blasted block size distribution (BBSD) prediction is the prediction of the in-situ block sized distribution (IBSD), the main subject of this paper. Drawing together research methods from the 1990s and the rock mechanics principles of discontinuity analysis, a practical step by step methodology for IBSD assessment that includes approaches that are not reliant on specialised computer software is presented. Continuing on the practical theme, a new extension of the volumetric joint count approach is suggested for IBSD prediction for the case when sparse borehole data is all that is available. A case study of IBSD assessment and the associated BBSD and blast assessment is presented from a Carboniferous limestone quarry. For clarity, details of blast design and yield curve prediction that are recommended for use in the context of armourstone production, have been presented in a companion paper. The Rosin-Rammler equation is used as an example form for the BBSD prediction of a dedicated quarry and the potential for breakwater project optimisation is illustrated. The final section sets out a method for directly comparing yield curves together with the demand for materials set by the breakwater design. On the same plot, sizes where there is a relative shortfall in production can be identified. The dependence of effective breakwater design on accurate quarry yield prediction and quarry blasting performance is discussed.     

High-pressure behavior of MnGeO3 and CdGeO3 perovskites and the post-perovskite phase transition

The stability and high-pressure behavior of perovskite structure in MnGeO₃ and CdGeO₃ were examined on the basis of in situ synchrotron X-ray diffraction measurements at high pressure and temperature in a laser-heated diamond-anvil cell. Results demonstrate that the structural distortion of orthorhombic MnGeO₃ perovskite is enhanced with increasing pressure and it undergoes phase transition to a CaIrO₃-type post-perovskite structure above 60 GPa at 1,800 K. A molar volume of the post-perovskite phase is smaller by 1.6% than that of perovskite at equivalent pressure. In contrast, the structure of CdGeO₃ perovskite becomes less distorted from the ideal cubic perovskite structure with increasing pressure, and it is stable even at 110 GPa and 2,000 K. These results suggest that the phase transition to post-perovskite is induced by a large distortion of perovskite structure with increasing pressure.     

A Simple Theoretical Radiation Scheme for Regular Building Arrays

We propose a simple theoretical radiation scheme for regular building arrays. The essential difference of the present radiation scheme from the previous ones is the explicit consideration of the three-dimensional features of the surface geometry. The model is assumed to be an infinitely extended regular array of uniform buildings, each building composed of six faces (roof, floor, and four vertical walls). Without using time-consuming iterations or statistical approaches, we calculated the view factors of the faces, the complicated sunlit--shadow distributions, and the resulting canopy albedo for any time and location. The model was evaluated by comparing to outdoor experiments in a wide range of seasons and surface geometries. The simulated canopy albedos agreed well with measured values, and the accuracy is a significant improvement over two-dimensional-based model outputs.     

电子地图的色彩配合实验

在地图的色彩设计中,设计人员不仅要考虑色彩单独使用的效果,而且要考虑地图上各素的色彩配合,即各种色彩在图面上的整体感受效果。电子地图由于有极大的色彩选择空间,背景色不局限于白色,因而选色、配色比纸质地图更加复杂。用哪种简称颜色作为背景视觉效果较好？图面上各要素的色彩如何配合？针对这两个问题,作者设计了电子地图的一个色彩感受实验－色彩配合实验,利用自编的电子地图视觉感受测试构件（ＴＥＶＰ）进行了实验     

1999年度中俄合作岩石破裂实验研究

１９９９年１１月～１２月,俄罗斯科学院圣彼得堡Ｉｏｆｆｅ技术物理研究所Ｖ．Ｓ．Ｋｕｋ－ｓｅｎｋｏ教授等专家应邀来华,与中国地震局地球物理研究所和中国科学院地球物理研究所合作,在震源物理实验室开展分米级尺度岩石破裂实验研究。实验中采用了ＳＤＡＥ－８型系统,进行声发射地定位和实时显示。实验采用了多种典型构造模拟和加－卸载方式,取得了丰富的成果。该实验开辟了国际间实质性合作的新途径。     

利用数字地震记录资料识别地震与爆破

利用西安数字地震遥测台网记录资料,通过对波形、P波与S波振幅比等方面进行对比分析,找出陕西及邻区地震与爆破的区别。