排序方式: 共有113条查询结果,搜索用时 250 毫秒
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分析了矽卡岩微观结构及软化原因,计算了软化系数,说明矽卡岩的软化性较大。通过单轴声发射试验和三轴定围压试验,研究了矽卡岩破坏全过程的声发射特征及围压对变形和强度的影响。结果表明,岩石声发射特征与变形特征紧密相关,围压对矽卡岩的变形和强度均有明显影响:围压增大,破坏阶段的变形减小,峰值强度和残余强度均明显增大。 相似文献
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关于土木工程专业工程实践性教学改革的探索与实践 总被引:3,自引:0,他引:3
近年来 ,高等教育的改革取得了令人瞩目的成绩 ,教学改革已迈出关键的一步 ,但是 ,统观全局 ,改革的发展是不平衡的。教学改革的力度、速度和深度均需进一步深化。以土建类专业工程和实践性教学为例 ,存在着观念陈旧 ,重课堂、轻实践的现象 ;制度上仍沿用认识、生产和毕业实习三段制 ,实践教学活动与课堂教学的融合性方面也存在一定差距。本文主要介绍我校土木工程专业实践性教学改革中进行的一些探索和实践。一、现状和问题自 1 995年“高等教育面向 2 1世纪教学内容和课程体系改革计划”实施以来 ,我校取得了一系列改革成果 ,特别是 1 999年下半年学校提出“转换机制、增强活力、提高办学效果”的方针后 ,教学改革更为活跃。新制定的 1 999年版教学计划中 ,土木工程专业工程实践类教学主要是“两实习”(认识、生产 )、“两设计”(课程、毕业设计 )。从时间长短看 ,工程实践类课程 (除基础理论实践如金工、计算机和外语类实践教学外 )达到了 2 5周 ,按 4年培养过程 1 4 4周计 ,占到 1 7.4% ,这对于与工程实际结合密切的土木工程专业而言 ,是切实合际的 ,也是进一步加强学生工程实践及动手能力培养的重要保障... 相似文献
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Measurements of in situ stress and mining-induced stress in Beiminghe Iron Mine of China 总被引:1,自引:0,他引:1
In order to obtain the distribution rules of in situ stress and mining-induced stress of Beiminghe Iron Mine, the stress relief
method by overcoring was used to measure the in situ stress, and the MC type bore-hole stress gauge was adopted to measure
the mining-induced stress. In the in situ stress measuring, the technique of improved hollow inclusion cells was adopted,
which can realize complete temperature compensation. Based on the measuring results, the distribution model of in situ stress
was established and analyzed. The in situ stress measuring result shows that the maximum horizontal stress is 1.75–2.45 times
of vertical stress and almost 1.83 times of the minimum horizontal stress in this mineral field. And the mining-induced stress
measuring result shows that, according to the magnitude of front abutment pressure the stress region can be separated into
stress-relaxed area, stress-concentrated area and initial stress area. At the −50 m mining level of this mine, the range of
stress-relaxed area is 0–3 m before mining face; the range of stress-concentrated area is 3–55 m before mining face, and the
maximum mining-induced stress is 16.5–17.5 MPa, which is 15–20 m from the mining face. The coefficient of stress concentration
is 1.85.
Foundation item: Projects(10702072, 10632100) supported by the National Nature Science Foundation of China 相似文献
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