软弱围岩隧洞施工性态的力学模拟与分析

本文着重对软弱围岩隧洞施工中的力学性态进行了计算机模拟和分析。文中除提出了考虑隧洞开挖面时空效应的三维分析模型外，还计入岩体流变时效，进行了弹－粘塑性数值计算。其中，研讨了开挖面推进过程中洞室围岩与错喷支护的相互作用以及设置整筑式二次内衬的影响。用所建议的力学模型和编制的程序软件，结合某实际工程，分别就洞室上下台阶法分部开挖、全断面法一次开挖和侧壁导坑法扩大开挖等三种最常见的隧洞施工作业方式进行了模拟分析，并将计算成果与现场实测数据作了比较验证。     

Mechanical Behavior and Shape Optimization of Lining Structure for Subsea Tunnel Excavated in Weathered Slot

Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang’an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of cross- sectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.     

基于粘性-滑移界面接触模型半空间隧道衬砌对平面P波的散射

基于粘性-滑移模型模拟隧道衬砌和围岩之间的接触状态,采用间接边界积分方程法求解弹性半空间中隧道衬砌对平面P波的散射,着重考察了地表位移放大和衬砌动应力集中效应。结果表明:接触滑移边界的刚度系数和粘度系数对隧道衬砌的动应力分布影响较大,滑移刚度较小时,共振频率段动应力集中效果更加显著;随着粘度系数的增大,衬砌内部环向应力幅值逐渐减小。另外,界面刚度系数和粘度系数对隧道衬砌动力反应的影响程度也受控于入射频率和角度。     

平面SH波作用下衬砌隧道对地下地震动的影响

以地下隧道对附近场地动力特性的影响为研究目标,基于弹性波动理论,利用波函数展开法和镜像法,分析了弹性半空间中圆形衬砌隧道对平面SH波入射产生的散射问题,得到了地下圆形衬砌隧道附近场地位移的级数解答。通过数值算例分析了地下圆形衬砌隧道对场地动力响应的影响,重点考察了SH波入射角度、入射频率和隧道埋深、衬砌刚度对隧道周围土体动力响应随深度变化的影响规律。结果表明,地下隧道对沿线场地的地下地震动影响显著。     

Seismically induced racking of tunnel linings

An analytical procedure is presented for evaluating the racking deformation of rectangular and circular tunnel linings caused by soil–structure interaction during a seismic event. The procedure, as applied to rectangular linings, is supplementary to that previously published by Penzien and Wu (Earthquake Engineering and Structural Dynamics, 1998; 27 :283–300) for circular linings. Copyright © 2000 John Wiley & Sons, Ltd.     

航空与卫星影像数据多尺度分割对比研究

本文从遥感影像多尺度分割的角度分析了同一地区的航片与QuickBird、IKONOS等卫星数据的分割效果,讨论了不同地物和不同影像的最佳分割尺度,以增强对目标物的检测与识别能力,提高现有航空遥感数据及卫星影像数据应用的精度和效率,并对最终分类结果进行了比较。结果表明航片、QuickBird、IKONOS的最佳分割尺度分别为125、100、75,QuickBird的分类精度最高,航片和IKONOS的分类精度次之。因此可认为,航片在实际应用中,可以代替高分辨率卫星影像。     

酒钢1~#高炉缸砖衬破损原因及钛沉积物的护炉作用

酒钢１＃高炉于１９９０年３月１２日在生产过程中突然发生坍塌,造成国内外冶金史上罕见的高炉生产特大事故。坍塌后对炉缸、炉底风口下沿粘土残砖、炉缸中部环碳砖、炉底高铝砖缝中渗结物等进行了分析,初步查明上述炉料中含有较多的碱金属氧化物Ｋ２Ｏ、Ｎａ２Ｏ及锌等有害元素是造成炉缸内粘土砖破损和碳砖产生环形裂缝的主要原因。１　物相组成１－１　化学成分分别从炉缸、炉底采取试样进行化学分析,结果列于表１。表１　试样化学成分（％）Ｔａｂｌｅ１　Ｃｈｅｍｉｃａｌｃｏｍｐｏｓｉｔｉｏｎｏｆｓａｍｐｌｅｓ（％）样品号Ｓｉ…     

模拟喷射混凝土或衬砌支护的大变形衬砌单元模型

本文利用大变形有限元的基本理论,提出了有限元大变形衬砌单元模型,并推导了其相关的大变形有限元计算公式,成功地解决了岩土工程喷射混凝土或衬砌支护的大变形有限元模拟计算问题,具有广泛的理论意义及实用价值。     

坑探工程在改革中的新发展

介绍了原地矿系统坑探工程从创建至今的队伍发展情况,以及在实现机械化,推广应用新技术,研究新工艺,新方法,新设备等方面的情况。     

近距离双隧道开挖与支护的稳定性有限元计算

对京珠国道粤境沿线某近距离双隧道开挖与支护过程,使用平面粘弹塑性有限元方法分５种计算情况进行了数值模拟,分析对比了围岩与支护结构的受力、变形及塑性、受拉区的演化状况,对围岩—支护体系的稳定性进行了评价。