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地下洞室围岩稳定性分析方法简述 总被引：3，自引：0，他引：3
随着可持续发展战略的提出,地下工程的开发和利用显得尤为重要。地下洞室围岩稳定性是整个工程中的关键问题,现今对地下洞室围岩稳定性研究的分析方法有很多,为了明确各种研究方法的优缺点以及适用范围,本文对现有地下洞室围岩稳定性分析方法进行了分类总结,用系统性的方法从定性、定量、可靠度等方面考虑,主要包括洞室的整体稳定性分析和洞室局部块体的稳定性分析,研究结果对地下洞室围岩稳定性设计及计算有重要的意义,最后对相关研究的现状和发展趋势做了简述。 相似文献
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本文总结大量隧洞施工经验，对洞室的破坏机理进行了分析，提出了影响洞室围岩稳定性的主要因素及分析评价方法：通过对各种变形形式的分析，提出了洞室的开挖支护方法及支护时间对围岩稳定性的影响，最后对有关洞室围岩稳定性分析方法的国内发展现状进行了总结。 相似文献
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低地应力区地下洞室开挖围岩剪应力静态数值模拟研究 总被引：2，自引：2，他引：0
本文以西北某市大型水利地下洞室工程为例,采用弹塑性二维有限元法对低地应力区洞室开挖后围岩剪应力分布与围岩变形破坏进行了数值模拟,总结出了低地应力区地下洞室开挖后围岩剪应力大小、分布规律与围岩变形破坏的关系.该项研究它将有利于进一步研究低地应力区地下洞室开挖后围岩稳定性,同时对保障地下洞室工程的圆满进行具有重要的理论价值和现实意义. 相似文献
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低地应力区地下洞室围岩压力计算方法及应用 总被引：1，自引：0，他引：1
以西北某市水利工程地下洞室泄洪洞等为例,对低地应力区地下洞室围岩压力计算方法与应用进行了研究。研究认为,低地应力区地下洞室围岩压力可分为拱顶横向拉张塌落型、侧壁切向挤压滑落型和洞周自重掉落石块型三种破坏类型产生的围岩压力,并讨论了低地应力区地下洞室围岩压力的计算公式。以研究区引水洞为例,分别计算了拱顶围岩整体滑落和侧壁围岩整体滑落型围岩压力。该项研究成果,它将有利于进一步研究低地应力区洞室围岩稳定性与相应稳定性措施的实施,有助于工程的顺利进行。 相似文献
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地下洞室中裂隙岩体围岩稳定性研究的模糊信息优化处理方法 总被引：3，自引：0，他引：3
基于地下洞室工程中裂隙岩体围岩分类及稳定性分级的实际资料,选取岩石单轴抗压强度、岩体ＲＱＤ值、裂隙间距、声波纵波波速等重要影响因素,运用模糊信息优化处理技术,建立了一套裂隙岩体围岩稳定性分级的评价方法;并应用于某水电工程地下厂房的围岩稳定性评价,体现了该方法简单、快速的特点。 相似文献
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岩浆房系统的稳定性决定于岩浆房本身的冷却和内部运动以及岩浆房周围岩体的挤压和振动等外界因素,一定条件下,外部因素可能起到更为重要的作用。以五大连池新期火山老黑山岩浆房为例,基于岩浆热传导方程和岩浆房系统振荡的杜芬方程组,通过数学变换和计算得到:五大连池新期火山岩浆房固结与否和岩浆房中岩浆的存在历史密切相关;围岩无预热条件下老黑山岩浆房已固结了6 0年左右,而在充分预热条件下,岩浆房尚需6 0年左右才完全固结,因此较保守的结论是岩浆房已近于完全固结。同时杜芬模型揭示火山区岩浆房系统可能存在复杂的非线性动力学行为。 相似文献
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Georgia Pe-Piper 《Contributions to Mineralogy and Petrology》1980,72(4):387-396
Mid-Miocene shoshonitic volcanism in Lesbos is preceded and followed by minor calcalkaline activity that probably terminated in the Pliocene. Two differentiation trends are recognised in the shoshonites. The older shoshonites include voluminous acid rocks (mostly ignimbrites) and show normal shoshonite REE patterns. They were probably derived from partial melting of garnet peridotite enriched in LILE, with later fractionation controlled by anhydrous phases. Cooling units in the ignimbrites show upward increase in the K content of glass, suggesting K-feldspar fractionation in a high level magma chamber. Later shoshonites and the calc-alkali rocks have HREE enrichment and contain hydrous cognate xenoliths. Partial melting of a rising periodite diapir which had been relatively enriched in HREE within the garnet stability field and then entered the spinel stability field, would produce the observed HREE enrichment pattern. Later fractionation of these younger shoshonites and calc-alkali rocks was controlled largely by hydrous phases. 相似文献
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辽西义县盆地火山岩的基本特征及其成因探讨 总被引：17，自引：0，他引：17
通过对辽西义县盆地火山岩的岩石学、矿物学以及地球化学特征的研究，指出本区火山岩属于一套弱碱性、普通型的火山岩系列．通过热力学计算以及对岩石结构和动力学的分析，表明原始岩浆来自上地幔（约６７ｋｍ），并在约１７ｋｍ处（上下地壳附近）形成高位岩浆房．在高位岩浆房中，由于岩浆的双扩散对流作用，发生了伴随有分离结晶作用的液相分异作用，而同化混染作用则发生于岩浆演化的早期。喷出的岩浆成分受断裂切过高位岩浆房的相对位置的控制。 相似文献
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The Tigalak intrusion is a dominantly dioritic layered body, about 80 km2 in area, which ranges in composition from norite to granodiorite. Local areas of the layered rocks display upward fractionation from norite to ferrodiorite. Periodic reversals of mineral composition trends record the emplacement of less fractionated dioritic magma. Heterogeneous mixtures of dioritic and granodioritic rocks occur widely in mappable lenses and layers that alternate up section and along the strike with more uniformly layered rocks. In these mixtures, chilled dioritic pillows occur abundantly in a hybrid cumulate matrix of granodiorite to diorite composition. Cross-cutting granodioritic dikes grade upward into stratigraphically-bound lensoid masses of the hybrid cumulates. It appears that the hybrid rocks formed as a result of the emplacement of the granodioritic magma through lower cumulates into the dioritic magma chamber and that the dioritic pillows represent chilled bodies of Ferich dioritic magma that commingled with cooler granodioritic magma and settled to the floor of the Tigalak magma chamber. The restricted distribution of these mixtures of hybrid cumulates and chilled pillows indicates that mixing between granodioritic and dioritic liquids was limited in time and lateral extent. Periodic injections of granodioritic liquids may have collected as a separate layer below the roof of the magma chamber and above dioritic magma. 相似文献
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甘肃景泰县老虎山地区蛇绿岩及其上覆岩系中枕状熔岩的地球化学特征 总被引：10，自引：3，他引：10
甘肃景泰县老虎山地区蛇绿岩之上覆盖着一套镁铁质的喷出岩和沉积岩组合，位于蛇绿岩的枕状熔岩之上，不是蛇绿岩的成员，为蛇绿岩的上覆岩系。蛇绿岩的枕状熔岩具Ｎ－ＭＯＲＢ的特征，而其上覆岩系中的枕状熔岩类似Ｅ－ＭＯＲＢ。前者来自扩张脊的下部岩浆房；后者推测源于扩张脊之外的岩浆房，也是软流圈地幔中等至高程度部分熔融的产物，不过，可能有少量来自下地幔的物质的加入 相似文献
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K.A. Dokukina A.N. Konilov T.V. Kaulina V.G. Vladimirov 《Russian Geology and Geophysics》2010,51(6):625-643
The paper reports the results of integrated geological, petrological, geochemical, and geochronological studies of the Tastau igneous ring complex in the Zaisan orogen of eastern Kazakhstan. Interaction between felsic and mafic magmas has been studied. Hybrid rocks are represented by gabbros and diorites injected into a granitic magma chamber. They occur as dikes and pillow-like and globular mafic bodies variously disintegrated and mixed with host granitoids. The age of synplutonic rocks is 242 ± 20 Ma (U/Pb zircon dating), which is, with regard to analytical error, substantially younger than it was presumed.Mechanisms of interaction between felsic and mafic magmas have been studied. They include mechanical (mingling) and chemical (mixing) interaction, which produce composite mixtures and hybrid rocks. The ratios of mafic to felsic components involved in the formation of intermediate rocks were calculated from major elements by regression analysis and tested with regard to rare and trace elements. The model for mingling includes rapid quenching of the mafic melt when it is injected into the granitic magma chamber, decomposition of crystalline fragments, dispersion of fragments and crystals in the magma chamber under conditions of rapid turbulent flow, and enrichment of felsic magma with femic components to produce monzonitic magmas. 相似文献
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赣南－粤北晚中生代双峰式火山岩地质特征及其意义 总被引：6，自引：0，他引：6
本文讨论了赣南—粤北晚中生代双峰式火山岩的地质时代、岩石组合、稀土元素及微量元素的特征,认为双峰式火山岩形成于板内环境,中基性火山岩和中酸性火山岩不是来源于同一个岩浆房,前者是由上地幔部分熔融形成的,后者是在前者诱发下地壳部分熔融而形成的。 相似文献
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The paper discusses the formation conditions of the Ary-Bulak ongonite massif (eastern Transbaikalia). Studies of melt and fluid inclusions have shown that, along with crystalline phases and a silicate melt, ongonitic magma contained aqueous–saline fluids of different types, fluoride melts compositionally similar to fluorite, sellaite, cryolite, chiolite, and more complex aluminum fluorides as well as silicate melts with abnormal Cs and As contents. An ongonite melt crystallized with the participation of P–Q fluids as vapor solutions, presumably NaF-containing and slightly admixed with chlorides. We studied the properties and composition of brine inclusions from Ca- and F-rich rocks on the margin of the massif. Depending on the thermophysical properties of the host rocks and ongonite melt, the duration of its crystallization has been estimated for a magma chamber of the size and shape of the Ary-Bulak massif. Magma chamber cooling has been modeled, and the density, viscosity, and Rayleigh number of the ongonite melt have been estimated from the composition of silicate glasses in melt inclusions. These data strongly suggest intense convection in the residual magma chamber lasting for centuries. We have calculated possible fluid overpressure during the crystallization and degassing of the ongonite melt in a closed magma chamber.Calcium- and fluorine-rich aphyric and porphyritic rocks on the southwestern margin of the massif might have formed by the following mechanism. Local decompression in the magma chamber quenched an oxygen-containing calcium fluoride melt accumulated at the crystallization front, and then these rocks altered during the interaction with fluids. When penetrating the marginal zone, a P–Q magmatic fluid which coexisted with the melt in the residual chamber cooled and changed its composition and properties. This caused the fluid to boil and segregate into immiscible phases: a vapor solution and a brine extremely rich in Cl, F, K, Cs, Mn, Fe, and Al. The fluoride and silicate liquids were immiscible; the silicate melts had abnormal Cs and As contents; changes in the composition and properties of the magmatic fluids caused them to boil and produce brines. All this is evidence for complex fluid–magma interaction and heterogeneous ongonitic magma during the crystallization of the Ary-Bulak rocks. These processes were favored by the low viscosity and high mobility of the F- and water-rich ongonite melt, intense melt convection in the residual chamber, and rising fluid pressure during its degassing. 相似文献