排序方式: 共有33条查询结果,搜索用时 15 毫秒
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基于可靠度理论建立顺层岩质边坡稳定的可靠性分析方法,获得顺层岩质边坡可靠指标和失稳概率的计算表达式。以某高切坡为例分析其稳定状态和失稳概率,并据此探讨不同粘聚力、内摩擦角、炸药量和爆心距条件下边坡失稳概率的变化规律。计算结果表明,粘聚力对边坡的失稳概率影响较大;随着内摩擦角的增加,边坡失稳概率近乎线性减小;当单孔药量从10 kg增大到160 kg后,失稳概率增幅97.10%;当爆心距小于20 m时,边坡的失稳概率减小的速度很快,而爆心距超过20 m后边坡失稳概率减小的幅度较小。考虑爆破振动的时效性,爆破荷载使边坡失稳概率增大49.61%,单次爆破振动的影响时间约6 s。 相似文献
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将剪切型危岩主控结构面按受力机理归纳为压剪和拉剪两种形式,其本质是Ⅰ-Ⅱ复合型裂纹的断裂扩展问题。应用最大应变能释放准则,建立危岩主控结构面开裂角θ0和断裂韧度GIC的计算方法。选取重庆万州首立山典型危岩进行计算,结果表明,其断裂角与基于最大周向应力准则的断裂角计算结果一致,主控结构面的开裂方向均是指向临空面方向,初步验证了方法的可行性。 相似文献
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随着经济的发展,电梯正越来越多应用于各种建筑物中,且趋向于微电子化,极易遭受雷击电磁脉冲的影响,造成运行中断。有些机房实施了相应的雷击防护措施,但还是未能避免设备的损坏。根据相关规范和理论,结合雷灾实例,就其雷击电磁环境进行分析,以期对实际运用有所借鉴,减少雷击灾害。 相似文献
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速流结构是公路泥石流防治体系中常用且有效的工程措施之一。文章基于底越式速流结构的受荷模式及边界条件,将汇流槽视为三次超静定梁,运用结构力学方法求解侧墙及嵌固桩的内力;将速流槽与嵌固桩引入Winkler模型,用弹性地基梁理论求解速流槽内力、位移及地基反力,由此提出底越式速流结构计算理论。以平川泥石流防治工程为例,进行内力计算。 相似文献
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In order to provide scientific references for lightning protection, the spatial and temporal distribution of lightning disasters and the characteristics in different industries are analyzed based on the lightning disaster data during 2007-2013 and specifications for statistic of lightning disaster state(QX/T 1912013) in Zhejiang province, from aspects of grade, time, space, casualty, damaged industry and facility, etc. The result shows that there are 3395 lightning disasters in Zhejiang province during 2007-2013, and June to August is the peak time. Besides, lightning disasters have strong regional characteristics, which are higher in Hangzhou, Jinhua and Lishui, and the lowest in Zhoushan. The injuries and deaths caused by lightning shows decreasing tendency from 2007 to 2013, and the number is higher in the rural than in city. The dangerous regions where injuries and deaths may caused by lightning are buildings without lightning protection systems, temporary buildings and structures, open area, or under trees. Lightning disaster are most harmful to the industries of manufacturing, rural residences, production and supply industries of electric power, gas and water, and telecommunication, while the greatest loss of economy is in the industries of manufacturing, rural residences, production and supply industries of electric power, gas and water. 相似文献
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本文研究基于SOM(Self-Organizing Feature Map)神经网络学习模型的高分辨率遥感影像道路网自动提取算法。首先利用数学形态学提取遥感图像道路的初始道路区域信息,自动对原始图像进行分区并确定神经元初始权值,用SOM网络学习模型对神经元进行训练学习,经迭代获取道路网中心点位置,最后运用"中心点四邻域跟踪判别法"跟踪连接形成道路中心线。实验表明,该方法在高分辨率遥感影像道路网的提取上有较好的效果,特别在主干道路网的提取上效果更佳,对噪声干扰具有良好的鲁棒性。 相似文献
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