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941.
Acta Geotechnica - This paper proposes a framework to identify geological characteristics (GC) based on borehole data and operational data during shield tunnelling using a fuzzy C-means... 相似文献
942.
Shen Weizhou Zhang Bangtong Ling Hongfei Lai Mingyuan Yang Jiedong Tao Xiancong 《《地质学报》英文版》1992,66(2):165-176
Nd, Sr and O isotopic study on the spilite-keratophyre sequence in Xiqiu shows that its ∈_(Nd) values are inthe range of 4.02-5.26, and its ∈_(Sr) values, +1.4-2.6. According to the points of these data in the ∈_(Nd)-T,∈_(Sr)-T and ∈_(Nd)-∈_(Sr) diagrams, the spilite-keratophyre is interpreted as being slightly contaminated by crustalmaterials. Its δ~(18)O values are 3.9-5.0‰. The depletion of ~(18)O in the rocks resulted from the influence ofseawater hydrothermal alteration during or soon after the rock formation. Based on the isotopic characteristicsand available geochemical data, it is believed that the spilite-keratophyre was formed in the well-developedisland-arc environment during the Late Proterozoic subduction of the palaeo-Pacific plate beneath thesoutheastern margin of the Yangtze massif. 相似文献
943.
利用中子活化示踪法研究坡面土壤的侵蚀过程,发现坡面的相对侵蚀量从坡脚到坡顶随坡长的变化符合Weibull分布,其形状参数主要受降雨量、降雨历时和径流深度的影响,尺度参数主要与平均雨强、I30相关.坡面在侵蚀的同时也发生沉积,一般来说短历时高强度的降雨沉积量较小,而长历时低强度的降雨沉积量较大,某一部位侵蚀产沙的沉积量与其距离之间有y=axb的关系.坡面径流直接影响着坡面的输移比,当径流深和径流系数较高时,输移比接近于1,否则输移比降低. 相似文献
944.
Yongping Shen 《GeoJournal》1991,25(2-3):249-254
On September 16th, 1986, an ice avalanche from a hanging glacier near the K2 peak at 7800 m asl, Karakorum, triggered a massive
avalanche of ice and snow. Ice and snow, impacting on the path, formed a dust cloud at the advancing tip. Grounding on the
firn basin surface, ice and snow broke into fine powder and covered the whole basin. Fine powder of the dust cloud rose up
to 500–600 m and drifted 4–5 km away. On the basis of field observations and measurements, topography and weather, conditions
of the avalanche formation are analyzed. Judging by the data obtained, the avalanche was extremely large, its vertical descend
being 2500 m, the maximum motion speed 124 m/s, volume of the avalanche mass 2 × 105 m3 to 107 m3, and impact pressure, as the avalanche grounded, 2.3 × 106 Pa. It could have been one of the largest avalanches ever recorded, causing danger for mountaineering and expedition activities
in this area. 相似文献
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为探究预应力锚杆对岩体板裂化破坏的控制机制,首先进行了岩体板裂化破坏的室内物理模型试验,并运用FLAC数值模拟技术,模拟了平面应变状态下板裂化破坏的形成过程;在此基础上,通过3种不同的预应力锚杆施加方案,进行预应力锚杆对岩体板裂化破坏控制机制的数值试验。研究结果表明:预应力锚杆的作用削弱了裂隙尖端应力集中现象,有效地抑制了岩体内裂隙的扩展与贯通、板裂化破坏的形成;作用在板裂区边界的预应力锚杆,不仅能够抑制板裂化破坏的形成,而且能在一定程度上控制板裂化破坏的范围;作用在板裂破坏区内的预应力锚杆,可有效限制板裂岩体向临空面的位移,体现出提高板裂岩体整体变形刚度的作用。研究结果对认识深埋隧洞围岩板裂化破坏的形成机制、板裂化破坏的合理支护控制以及岩爆防治具有重要指导价值。 相似文献
950.
There was a famous saying by Sage Archimedes over 2,000 years ago that giving him a long enough lever and a fulcrum, he would tilt the entire earth. As an old driller, I propose another non‐famous saying that giving me a chance to drill a coring hole, and I will create a telescope to insert the deepest earth for you. Nowadays, drilling is one of most significant methods to collect samples from the deep earth. Those samples are extremely important for geoscientists to focus on the dynamic evolution of deep earth. Therefore, drilling engineering is thought to be inseparable for the geosciences. Unfortunately, some young geologists, especially students majoring on geology, have no meanings of what the drilling is, and of the importance for their geological researches. In this case, education popularization drilling knowledge should be strengthened in future. And we hope that sufficient attention of drilling engineering will be taken by geologists in the world. Moreover, in order to obtain high‐quality cores by various coring drilling methods. Drilling techniques and special coring tools must be continuously developed to successfully perform with regard to a variety of complex geological conditions. We have developed coring tools these years as follows: Splitted core barrel Triple tube coring drill tool, Advanced tube coring tool, Vacuum suction coring tool, Shock‐type coring tool, Long core barrel coring tool, WL‐drilling system with hydro‐hammer, WL‐drilling system with mud motor. These new coring tools have played a very important role in China's scientific drilling program. All in all, without advanced drilling technology, pickup of high quality samples from the deep Earth and geological research on the dynamic evolution will be restricted. 相似文献