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991.
This paper proposes an extension to the key‐block method, called ‘key‐group method’, that considers not only individual key blocks but also groups of collapsable blocks into an iterative and progressive analysis of the stability of discontinuous rock slopes. The basics of the key‐block method are recalled herein and then used to prove how key groups can be identified. We reveal that a key group must contain at least one basic key block, yet this condition is not entirely sufficient. The second block candidate for grouping must be another key block or a block whose movement‐preventing faces are common to one or more single key blocks. We also show that the proposed method yields more realistic results than the basic key‐block method and a comparison with results obtained using a distinct element analysis demonstrates the ability of this new method. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
992.
岩石可钻性的合理分级,是正确选择钻进方法、技术参数、钻头类型和制定合理的生产与物化定额、专核钻探生产技术与经济指标的科学依据。利用与岩石可钻性密切相关的物理力学性质—压入、摆球硬度、研磨性、塑性系统与声学特性为自变量,以微钻钻速为因变量,在计算机上进行一元和多元回归分析,建立其数学模型,以此将不同岩石划分为12级。这种方法具有较强的模拟性、代表性和较大的适用范围。 相似文献
993.
U.?M.?Rao?KaranamEmail author S.?K.?Dasyapu 《Geotechnical and Geological Engineering》2005,23(3):297-308
Rock bolts are widely used for rock reinforcement in hard-rock mining and civil engineering since a long time. However the use of fully grouted rock bolts and cable bolts is limited in coal mines. In order to improve performance of the rock bolts as a supplementary roof support system for any type of roof condition in coal measured formations, it is necessary to have a good understanding of the behavior of the bolt–grout and grout–rock interactions as well as the mechanism of load transfer in rock bolts.As the performance of grouted bolts depends on bond strength, extensive laboratory pullout as well as pushout tests were conducted in the present investigations with the variations in the bolt diameters, length and cement–water mixing ratios of grout. The load–displacement curves were developed and were verified with the numerical results obtained from finite element analysis using ALGOR software.Numerical models were validated for pushout tests and a detailed analysis was carried out to know the displacement, stress, strain distribution along the bolt. 相似文献
994.
995.
岩石的应变组构型式与岩石成分、变形环境和应变过程有着密切关系。北瓦沟地区低角闪岩相条作下的长英质岩石,表现脆性、韧性和韧脆性过渡,因而在剪切作用过程中形成了相应的应变组构型式,即脆性应变组构、韧性应变组构和脆-韧性应变组构。而且随着应变过程的发展,应变组构也表现出一定的演化规律。 相似文献
996.
通过野外对三座庙序列侵入岩的岩体平面与剖面形态、岩体的内部构造、岩石与围岩的构造型式、接触带的度形特征等宏观地质特征的研究,推测岩体侵入位机制为强力挤入方式定位,即气球膨张式。笔者运用岩石的有限应变测量原理和方法,结合岩组分析及流变学、现代变形理论,对三座庙序列的侵入岩岩石做了有限应变测量和岩组分析工作,所得定量资料为确定岩体的浸位机制提供了理论依据。三种岩石有限应变测量,即:算术平均法、长短轴法、Rf/φ曲线法的富林指数k值均在0相似文献
997.
998.
999.
WANG Yuwang WANG Jingbin WANG Lijuan WANG Yong TU Caineng Beijing Institute of Geology for Mineral Resources Beijing Key Laboratory of Mineral Resources Research Institute of Geology Geophysics Chinese Academy of Sciences Beijing Xinjiang Kalatongke Cu-Ni Mine Fuyun Xinjiang 《《地质学报》英文版》2004,78(2):396-403
On the basis of the study on the REE geochemistry of the ore minerals and host rocks of the Kalatongke Cu-Ni deposit, Xinjiang, it is indicated that the major ore minerals, sulfides, were sourced from the host mafic-ultramafic magma. Characterized by low REE content of sulfide, such a Cu-Ni sulfide deposit occurring in the orogen is obviously different from that on the margin of the craton. Because the mafic-ultramafic rocks from the Cu-Ni sulfide deposit occurring in the orogen is water-rich and the REEs of some sulfides show a particular "multiple-bending" pattern, which suggests coexistence of multiple liquid phases (fluid and melt), the sulfide melt possibly contains a great deal of hydrothermal fluids and increasingly developed gases and liquid-rich ore-forming fluids after the main metallogenic epoch (magmatic segregation stage). 相似文献
1000.