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锚杆能够显著增强顺层岩质边坡的稳定性.基于顺层边坡结构效应,应用锚杆加固顺层边坡的力学模型,根据结构力学理论和变形协调关系,建立拉剪作用下全长粘结型锚杆加固顺层边坡抗剪计算的理论分析方法.与相关试验数据进行了比较验证,结果表明顺层边坡锚固抗力模型计算结果与试验结果比较一致,验证了理论模型的合理性.讨论了锚杆倾角、锚杆直径、灌浆体强度、结构面内摩擦角、剪胀角等对加锚顺层岩体抗剪性能的影响.分析表明:锚杆锚固抗力模型能够较好地反映锚杆轴力及横向剪切力对顺层岩质边坡的抗剪作用.锚杆倾角越大,锚杆总的抗力呈减小趋势,而锚杆抗力随剪胀角增大而增加;当锚杆倾角等于内摩擦角时,锚杆抗力达到最大;锚杆抗力随锚杆直径增加而增大;当锚杆直径不变时,锚杆抗力随灌浆体抗压强度增大而有所减小. 相似文献
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系统锚杆对三峡船闸高边坡岩体加固作用的块体相似模型试验研究 总被引:22,自引:4,他引:22
通过室内相似模型试验,对三峡船闸高边坡岩体的分离块体经系统锚杆加固后,其抗压强度、弹性模量及C、值的提高、锚固岩体的各向异性进行了初步研究,得出了相应的结论。 相似文献
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Three rock reference samples. W-2, DNC-1, and BIR-1, were analysed five times over several months by classical chemical methods using a Youden Square as the experimental design. A significant variation for the data classified by months was found for SiO2 , CaO, H2 O- , and TiO2 among the 15 constituents determined. Nevertheless, most standard deviations for the five data for each oxide in any sample, as well as the error standard deviations from the analyses of variance, are less than or approximately equal to the allowable difference between duplicate determinations traditionally used as limits of error. We also determined nine constituents in three portions each of two samples, W-2 and DNC-1, the six portions being analysed concurrently. F ratios for 16 comparisons of the variances of the five data for an oxide obtained over several months and of the three data determined as a group were significant for only one oxide, total iron as Fe2 O3 in W-2. We conclude that, if a chemist analyses rock samples carefully, the variation of the determinations will be the same for portions analysed as a group, or analysed over a time interval. 相似文献
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Analysis of Cracking in Rock Salt 总被引:4,自引:0,他引:4
Summary ?The use of underground mines in salt-rock formations for waste repositories makes the precise analysis of isolation properties
of rock salt very important. One of the main mechanisms responsible for a degradation of isolation ability of the rock salt
is the generation and development of cracks under influence of mining processes. Various aspects of cracking in salt rocks
are studied – both in situ and in laboratory tests – for rocks of the world's largest Verkhnekamskoe potash-ore deposit (Russia). It is shown that not
all the discontinuities (fractures) are closed in the course of the creep deformation of rocks. Parameters of cracking are
determined for various conditions: age of pillars, mining technology, etc. Different methods – filtration, electrometric,
nuclear magnetic resonance, mechanical tests – are used for crack observation and characterisation, both in specimens and
in situ. Traditional investigations (partly with specially designed equipment) are accomplished by the testing methods of fracture
mechanics for determination of critical values of stress intensity factors K
Ic and K
IIc. The problems and ways of the use of the obtained results in analysis of isolation properties for areas in vicinity of underground
mines and/or waste repositories are discussed. 相似文献
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A discrete element code has been used to simulate impact-induced rock fragmentation in rock fall analysis using a simplified
impact model inspired by the theory of vibrations for foundations on elastic media. The impact velocity, the angle of incidence,
pre-existing fractures, and the ground stiffness all play important roles in impact fragmentation. Based on the simulation
results, impact fragmentation occurs locally at the impact zone without generating large fragments for a homogeneous rock
block. Large fragments are generated only when there are open pre-existing fractures in the rock block or when there are fully
persistent closed fractures. Softer ground tends to reduce the potential for impact fragmentation. Energy transformation and
failure occur only during impact including approach and restitution stages. Friction energy loss accounts for most of the
energy loss during the fragmentation process, while tensile cracking energy loss is not significant. 相似文献
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岩石边坡,尤其是裂隙岩体边坡稳定性分析应考虑岩体中结构面的产状、性质和发育程度。对随机发育的岩体结构面,赤平极射投影是确定优势结构面及分析边坡潜在破坏模式的基础。以某电厂高100m以上岩石高边坡为例,介绍了采用赤平投影图解法及极限平衡法,进行岩体边坡稳定性分析的方法。 相似文献