一次造成乌鲁木齐市电网瑶线铁塔倒塌事故的气象原因分析

为了解2004年11月24日乌鲁木齐市两座电网瑶线铁塔倒塌事故的气象原因，通过实地调查，并对高低空环流形势场、加密气象站信息等进行了分析。结果表明，乌鲁木齐地区不同地理位置风速差异很大，红雁池和头屯河区瞬间极大风速分别比市区大12．8m／s和18．4m／s。纠正了过去认为东南大风的强中心只出现在红雁池附近的说法，为今后制作大风分区预报提供了参考，也可为城区高层建筑及相关设计规范的修正提供借鉴。     

安庆铜矿综合治水工程及其评价

介绍安庆铜矿矿山的生产及水文地质概况，指出矿山生产中存在的水文地质、环境地质等问题，提出总体治理方案和实施措施，对治水工程进行了综合评价。     

How to obtain alert velocity thresholds for large rockslides

A reliable forecast of the failure stage of large rockslides is difficult, because of non-linear time dependency of displacements and seasonal effects. Aim of this paper is to suggest a practical method to prepare alert thresholds for large rockslides, assessing critical values of velocity for carrying out civil protection actions using monitoring data. Adopted data concern the 20 Mm³ Ruinon rockslide (Valfurva, Central Alps, Italy), still evolving and suitable to originate a fast moving rock avalanche. Multitemporal analysis of aerial photos, LIDAR-ALTM laser topography, field survey and geomechanical analyses allowed to infer the rockslide kinematics and better understand data provided by a monitoring network including distometers, extensometers, GPS benchmarks and inclinometers. The analysis of displacement and rainfall data over five years (1997–2001) allowed to recognise three different evolutionary patterns of displacements, showing a continuously increasing rate since 1997. Data representing large-scale behaviour of the rock mass were fitted by power-law curves, according to the “accelerating creep” model by Voight, in order to evaluate a suitable failure time. This was hampered by the large seasonal deviations, which can significantly delay the occurrence of failure. Data were fitted using the Voight’s equation, expressed in terms of displacement, through non-linear estimation techniques, in order to find values of the controlling parameters (A, α and t_f) suitable to represent the mechanical behaviour of the rock mass approaching the failure. This allowed to compute velocity–time theoretical curves and to define different velocity threshold values (pre-alert, alert and emergency) to be used for emergency management.     

深圳市地质灾害及防治技术

深圳市是一座新兴的海滨城市，市区东部与西部以花岗岩为主，中部以古老的变质岩为主，部分地区分布有砂岩、泥岩及变质的板岩、粉砂岩，深圳大断裂是区内主要的构造形迹。滑坡地质灾害主要分布在中部。在花岗岩地区主要变形为岩质高边坡崩塌、落石、坍塌等坡面变形；在变质岩、砂岩、泥岩地区发生多处滑坡。地质构造与地质灾害关系密切，深圳大断裂两侧为地质灾害多发区。防治边坡变形的工程措施即桩排、连续墙、基础为桩，锚杆框架；预应力锚索、预应力锚索框架护坡、预应力锚索抗滑桩，设置多级平台减载及琉干排水措施。深圳采用的治理地质灾害的工程措施经过多年的使用达到预期效果，但在上世纪90年代初完成的工程很少考虑工程措施与城市的景观协调。90年代后期已经考虑了工程完成后对城市环境的影响。因此采用防护措施以锚杆框架、预应力锚索框架工程为主，框架间植草，既有利于边坡稳定又有利于美化环境。     

阜新矿区地面塌陷灾害对土地生产力的影响

在研究地面塌陷对一个地区的影响时，一般只侧重于其对建筑物、铁路的影响，而对土地生产力影响的探讨和研究还不够深入。对于阜新矿区来说，地面塌陷对该区土地生产力的影响更是空白，前期的工作仅仅侧重于地面塌陷的调查，如果就地面塌陷对土地生产力的影响做一决的概括和分析，无疑会给今后治理由地面塌陷带来的灾害提供借鉴作用。本文结合大量实测、实算数据，应用土地复理论与方法对地面塌陷引起的土地侵蚀、土壤盐碱化、土壤湿度、土壤质量水平等四个方面做了较为系统的阐述，并对灾害的治理提出了见解。     

金风口地面塌陷及水源干枯成因及防治

通过对金风口片区地表的调查，分析了地面降沉、塌陷的原因；研究了塌陷对水源的影响；总结了水源干枯的规律及影响因素；并提出了防治的办法及合理化建议。     

马来西亚沙捞越邦达、什兰江控矿角砾岩筒构造对比研究及其找矿意义

马来西亚沙捞越邦达、什兰江控矿角砾岩筒构造均为典型的浅成—半浅成角砾岩筒构造，角砾岩及控矿类型具有明显的垂向分带特点。邦达控矿角砾岩筒构造发育角砾岩筒上段的塌陷角砾岩，角砾岩筒剥蚀深度较浅，控制典型的高硫化型浅成低温金铜矿床，且其深部具有较大的找矿潜力。什兰江控矿角砾岩筒构造发育角砾岩筒下段的爆发角砾岩和中段的流化角砾岩，分别控制斑岩型金矿化和低硫化型浅成低温热液型金矿化，角砾岩筒剥蚀深度较大，对矿床的保存和找矿极为不利。     

南京市玄武湖水下交通隧道环境地质评价

玄武湖地下交通隧道既在城市,又在水下,环境地质条件极为复杂,是一种脆弱环境下的典型的地质工程。本文对玄武湖地下交通隧道的环境地质条件特别是水文地质条件进行了评价,预测了可能出现的如水污染、地面沉降、地面塌陷、巷道突水等环境地质问题,并提出了相应的防治对策。     

Application of extended distinct element method with lattice model to collapse analysis of RC bridges

This paper proposes a simple lattice model for collapse analysis of RC bridges subjected to earthquakes by using the extended distinct element method (EDEM). In the model, a concrete element consists of lumped masses connected to one another by springs, and a reinforcement bar is represented by a discrete model or an integrated model. The proposed lattice model is simple but its parameters are reasonably defined. It has fewer element nodes and connecting springs, which will be of benefit by shortening the CPU time. The processes to determine the initial stiffness of concrete and steel springs, the parameters of the constitutive model and the fracture criteria for springs are described. A re‐contact spring model is also proposed to simulate the re‐contact of the concrete after fracture of springs; and a general grid searching method is used to decrease the CPU time for judging re‐contact after fracture. The lattice model is assessed by numerical simulations and experiments. As an application, a damaged single‐column pier subjected to the Kobe Earthquake in 1995 is analysed by EDEM with the proposed model. The simulation results indicate that the proposed model predicts well qualitatively the collapse process of RC bridges. Copyright © 2003 John Wiley & Sons, Ltd.