水电站地下厂房大型岩体洞室的抗爆性能

通过大量的数值模拟试验,以洞室岩体和混凝土衬砌结构的损伤为指标,研究了水电站地下厂房这类大型岩体洞室在强地表爆破荷载作用下,洞室埋深、围岩岩体强度和地应力对洞室抗爆性能的影响。数值计算中,洞室岩体和混凝土衬砌均采用弹塑性损伤本构模型,同时考虑了几何非线性效应。研究结果表明:对于水电站地下厂房这类高边墙洞室,浅埋深洞室的抗爆性能较差,深埋深洞室的抗爆性能较强;岩体强度越高,洞室的抗爆性能越强;当地应力侧压因数λ1时,随地应力侧压因数的增大,洞室的抗爆性能显著下降。 更多还原     

水-岩作用对岩石抗压强度效应及形貌指标的实验研究

通过测定金川岩样的含水率以及水对岩石抗压强度,采用精度高达0.5μm的Talysurf CLI2000三维表面激光形貌仪,对经过矿井深部地下水作用前后的四种不同岩性的岩石试件进行形貌扫描,结合八个形貌参数作出定量分析对比。实验表明:矿岩遇水软化,岩石抗压强度降低,破坏时不属于脆性破坏,其原因可能就在于由于其中的粘土矿物吸水,当受力压缩时,水受压排出产生压密现象。水-岩作用后岩石表面形貌高度的离散性、粗糙程度变大,高度的分布概率更为集中,由负偏态变为正偏态且高度分布的对称性好于作用前。峰点算术平均曲度Ssc都有规律地降至0.62附近,更具协调性。     

清江水布垭水电站地下厂房岩体质量评价及反馈设计研究

考虑地下水 ,地应力及结构面产状和岩溶、剪切带发育的特点修正 ,确定了水布垭水电站地下工程洞室工程岩体质量 ,进行了地下工程的 RMR分类研究 ,讨论了与水布垭地下工程反馈设计及信息法施工的有关问题。     

矿山工程地质综合研究方法及在金川二矿区的应用

针对地下矿山工程的特点、研究现状及存在的问题 ,本文结合金川二矿区深部工程地质研究 ,提出了分项→综合→应用的矿山工程地质综合研究方法。该方法已经应用于金川二矿区二期工程无矿柱大面积连续开采矿岩突变失稳风险预测 ,取得了重要成果 ,为二期开拓工程设计及开采顺序的优化设计提供了重要依据。     

Micro–macro approach for the rock salt behaviour

Rock salt is considered as a pure aggregate of halite (mineral NaCl) crystals and its behaviour is investigated by a micro–macro approach. The behaviour of the polycrystalline aggregate is deduced from the properties of the constituent halite crystals. A model for the elastoplastic behaviour of halite crystal has been deduced from experimental data available in the literature. The basic equations of the micro–macro model for the polycrystalline medium and the calculation method are then presented and the elastoplastic behaviour of rock salt is investigated by this method. The hardening effects obtained for the polycrystal are found to be very different from those obtained for FCC metal polycrystals. The differences are explained as a consequence of differences of families of glide systems in these crystals. Finally, the internal stresses in the polycrystal are studied in order to elucidate the origin of cracking and damage of the rock salt.     

液相等离子体岩石爆破机理初步研究

建立了以NaCl溶液和高能量电容器组构成的等离子体模型试验系统 ,并将其用于岩石爆破试验。试验结果表明 :液相等离子体具有破碎介质的能力 ,试验系统是可靠的 ;与传统的炸药爆破相比 ,等离子体岩石爆破具有不产生粉尘、无炮烟、无有毒气体、无抛掷、低噪音等特点。     

岩石爆破损伤断裂的细观机理

基于现有岩石爆破机理和岩石细观损伤力学 ,认为岩石爆破损伤断裂过程包含有爆炸应力波的初期动态损伤演化阶段和后期爆生气体作用下的准静态损伤演化阶段 ,并分别建立了这两个阶段的损伤模型和断裂准则 ,阐述了岩石爆破损伤断裂的细观理论。     

岩心孔隙介质中流体的核磁共振弛豫

弛豫时间是核磁共振研究中的一个重要参数,岩心孔隙介质流体的弛豫过程是自由流体弛豫机制、表面弛豫机制和流体的扩散弛豫机制共同作用的结果,它包含了丰富的孔隙和流体本身的信息. 弛豫时间和自扩散系数的测量及对弛豫时间的分析是核磁共振技术应用于岩心分析和石油勘测的重要内容.     

Method to calculate fatigue fracture life of control fissure in perilous rock

Rupture and safety of perilous rock are dominated by control fissure behind perilous rock block. Based on model-Ⅰand model-Ⅱstress strength factors of control fissure under acting of weight of perilous rock, water pressure in control fissure and earthquake forces, method to calculate critical linking length of control fissure is established. Take water pressure in control fissure as a variable periodic load, and abide by P-M criterion, when control fissure is filled with water, establish the method to calculate fatigue fracture life of control fissure in critical status by contributing value of stress strength factor stemming from water pressure of control fissure in Paris's fatigue equation. Further, parameters (C and m) of sandstone with quartz and feldspar in the area of the Three Gorges Reservoir of China are obtained by fatigue fracture testing.     

Rock hyraces: a cause of San rock art deterioration?

San rock art sites are found throughout southern Africa, many showing signs of deterioration. In order to conserve this invaluable heritage, a long‐term multidisciplinary project has been launched to monitor the rate of their deterioration and determine the various chemical processes that are possibly contributing to the decay. This study was initiated to establish if Raman spectroscopy could contribute to this project and since rock hyrax colonies live in close proximity to many of these archaeological sites, the possible influence of their metabolic products on the deterioration process was investigated. The precipitates from the urine of rock hyraces were analysed with Raman and Fourier‐transform infrared (FTIR) spectroscopy. Where the urine was in contact with the faeces, the precipitates are a mixture of vaterite (a rare polymorph of CaCO₃) and the hydrated salt calcium monohydrocalcite (also rarely found in nature). On areas where this contact is at a minimum the common and stable polymorph of CaCO₃, calcite, is the main component. SEM micrographs and XRD analysis support the Raman and FTIR results. XRD, FTIR and preliminary GC‐MS analyses of hyraceum, the fossilised mixture of faeces and urine, identified an inorganic phase (potassium chloride, with small concentrations of other salts, e.g. vaterite and weddelite) and an organic phase, which is a cocktail of various aromatic compounds, mainly amides, alcohols and acids. These compounds could contribute to the crystallisation of these rare carbonates, as well as other uncommon salts detected on the cave walls, such as syngenite. The presence of phosphates in the urine may further act as a stabilizing agent. Copyright © 2007 John Wiley & Sons, Ltd.