地下水位下降对井壁破坏的影响分析

在用“２Ｄ σ”软件对所建模型进行数值计算的基础上, 分析了因采煤引起淮北矿区下部含水层水位下降而对井壁产生的影响。其表现为： 下部含水层水位下降将引起地层压缩沉降; 地层与井壁间产生附加应力, 并在基岩下部产生应力为零的中性点; 轴向应力由小变大; 当第一含水层和下部含水层同时有水位下降时, 也有类似的规律。计算结果与淮北诸矿井壁变形位置及变化状况基本相符, 因此在此基础上进行的井筒优化设计具有实际指导意义     

考虑震害因子耦合作用的砌体建筑群破坏概率模型研究

砌体建筑群在地震中往往破坏严重损失巨大,合理评估地震作用对不同种类砌体结构造成破坏的风险变得至关重要。传统基于后验概率的地震危险性分析方法忽略了砌体建筑个体差异性的影响,未深入考虑多种震害因子的耦合作用。本文以华南地区砌体建筑群为例,开发了一种集成概率方法来对城市砌体结构的破坏风险进行建模,考虑建筑年代、层数、使用用途和墙厚四类震害因子的耦合影响,采用(Kolmogorov-Smirnov)K-S检验,在设定地震动参数下选取Gaussian分布、Log-Normal分布、Gumbel分布和Beta分布四种概率分布对该地区砌体建筑物的破坏状态概率分布参数进行拟合。通过均方根误差(Root Mean Square Error)RMSE进行拟合优度评价,最终建立基于Gaussian分布和Log-Normal分布的砌体建筑物破坏联合概率模型。最后,以华南地区三个城市典型砌体建筑物为例进行实例对比验证,将基于本文建立的建筑破坏概率模型推算出的砌体建筑群震害矩阵与基于单体结构分析得到的震害矩阵进行对比,与理论值最大偏差为0.033 3。研究表明：本文构建的集成概率方法能够获得更加合理的城市砌体建筑...     

2017年8月9日精河6.6级地震烈度分布与房屋震害特征分析

通过对2017年8月9日精河6.6级地震灾区内共计355个调查点的实地调查,确定了此次地震的烈度分布。灾区最高烈度为Ⅷ度（8度）,灾区面积15623km²,灾区总人口487696人,其中,受灾人口133695人,地震共造成36人受伤;对各烈度区内不同结构类型房屋的震害现象进行了整理,分析了不同结构类型房屋的抗震能力与震害原因,结果显示,土木结构房屋倒塌及屋檐塌落是导致人员受伤的主要原因;砖木结构房屋缺乏抗震设施,破坏形式多样;砖混结构房屋在高烈度区破坏较重;框架结构房屋主体完好但填充墙普遍出现破坏。安居富民房屋抗震性能良好。     

基于裂隙尖端放电机制的深部岩体损伤自电特征分析

在大规模深部岩体损伤过程中发生的裂隙尖端放电现象往往引发地下雷电,对该现象发生机理、表现规律的揭示有助于地震、岩爆等的临灾预报.不同于在岩土体中液固耦合界面上发生的自然电场异常机理,在岩土体内部发生的裂隙尖端放电可谓是引发自然电场异常的另一重要微观机制.本文基于现有裂隙尖端放电的研究成果,详细阐述了裂隙尖端放电发生的过程,解释了岩体损伤过程中自然电场异常产生的微观机理,并结合室内实验成果论述了自电位的主要特征;进行了理论推导,认为在大尺度岩体连续损伤过程中,自电位具有含脉冲状波动并整体下降的特征;开展了原位测试,结果证明人工采掘扰动下的深部岩体连续破坏的过程中,自电位在破坏前期缓慢下降,在破坏过程中会出现脉冲状波动,随着破坏程度的加剧整体呈现波动中下降的规律,与理论推导、室内实验结论都相符.对比室内实验和原位测试成果发现,随着研究目标的空间尺度由mm级别扩展到m的级别,自电位波动的幅值也从数十个mV扩展到数百甚至上千mV,故认为在利用自电位波动规律来预测岩体破坏状态时,须受研究对象的空间尺度的约束.此外,在原位测试中发现,自电位对岩体损伤过程的响应较直流电阻率而言具有时域上的超前优势,并对此现象进行了解释.     

浙江省梅汛期洪涝灾情分析和预测

通过所构设的雨涝强度、雨涝影响面积等统计量来估计灾情，有较高的正确率，能估计出极端情况，为灾害评估工作提供了新的思路。     

Study on Seismic Damage to Buildings from the 2016 Hutubi MS6.2 Earthquake

Based on the field investigation of the building types and damage caused to them by the Hutubi M_S6.2 earthquake on December 8, 2016, we analyzed the damage characteristics and causes for different types of buildings. In conclusion we put forward some suggestions for the restoration and reconstruction in the earthquake affected area in future.     

Influence of earthquake ground‐motion duration on damage estimation: application to steel moment resisting frames

This paper presents an analytical study evaluating the influence of ground motion duration on structural damage of 3‐story, 9‐story, and 20‐story SAC steel moment resisting frame buildings designed for downtown Seattle, WA, USA, using pre‐Northridge codes. Two‐dimensional nonlinear finite element models of the buildings are used to estimate the damage induced by the ground motions. A set of 44 ground motions is used to study the combined effect of spectral acceleration and ground motion significant duration on drift and damage measures. In addition, 10 spectrally equivalent short‐duration shallow crustal ground motions and long‐duration subduction zone records are selected to isolate duration effect and assess its effect on the response. For each ground motion pair, incremental dynamic analyses are performed at at least 20 intensity levels and response measures such as peak interstory drift ratio and energy dissipated are tracked. These response measures are combined into two damage metrics that account for the ductility and energy dissipation. Results indicate that the duration of the ground motion influences, above all, the combined damage measures, although some effect on drift‐based response measures is also observed for larger levels of drift. These results indicate that because the current assessment methodologies do not capture the effects of ground motion duration, both performance‐based and code‐based assessment methodologies should be revised to consider damage measures that are sensitive to duration. Copyright © 2016 John Wiley & Sons, Ltd     

大震下村镇建筑砌体结构的抗震性能数值分析

为探讨村镇建筑低层砌体结构在大震下的动力响应及损伤分布情况,基于农居结构性能实地调查与检测,在有限元软件ABAQUS中建立了不同抗震构造措施的砌体结构有限元模型,并进行结构动力特性及大震下弹塑性时程的分析,对比它们的自振特性参数、位移响应参数及损伤破坏形态。分析表明,低层砌体结构合理设置构造柱后结构自振周期略有减小,但振型不变;在弹性变形阶段构造柱能有效约束结构的动力位移响应,进入塑性变形后构造柱可提高砌体结构的耗能能力,但值得注意的是,结构刚度退化后构造柱会加剧纵横向抗侧刚度的不均衡性;低层砌体结构合理设置圈梁构造柱可有效抑制承重横墙的裂缝发展及楼屋盖发生支座失效破坏,且可以明显削弱结构的扭转效应。     

基于高分辨率影像的九寨沟7.0级地震道路震害评估

2017年8月8日九寨沟7.0级地震引发贯通重灾区的S301省道、Z120县道多处损坏,给应急救援和灾后重建带来较大困难。利用高分辨率无人机和卫星影像可以对道路震害情况进行评估。本文首先对道路震害进行破坏类型和破坏等级的划分,针对不同分辨率影像所表现的道路破坏特征,建立各破坏等级、各损坏类型的解译标志,并完成灾区遥感图像覆盖范围内主要道路震害的研判与评估。经统计分析,研究区域共出现110处明显破坏,其中,68处为部分损坏,42处为完全损毁,道路整体破坏严重。     

Characteristics and Analysis of the Seismic Damage from the MS7.0 Jiuzhaigou Earthquake in the Area between Songpan and Jiuzhaigou

This paper expounds the features of the buildings and analyzes the seismic disaster characteristics of the Jiuzhaigou M_S7. 0 earthquake in the area between Songpan and Jiuzhaigou. New buildings (especially the frame structure) had good anti-seismic performance,but brick-wood structures and brick-concrete structures sustained large amounts of damage in the earthquake. By computing the seismic damage index,we found that the seismic damage index of the frame structure was far less than that of civil structures and brick-wood structures. The seismic damage index of frame structures were all zero in the Ⅵ area,and increased rapidly with the increase of intensity,but the increasing range was reduced. We also discussed how to evaluate the intensity in areas where there was a lack of buildings or there was only one structure type,which can be referenced in future field work.