共查询到20条相似文献，搜索用时 140 毫秒
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针对龙门石窟灰岩水溶液侵蚀破坏现象,考虑石窟区的泉水、石窟渗水和雨水的化学成分,配置不同的化学溶液,研究不同化学溶液作用下龙门石窟灰岩的力学损伤特性及化学溶解行为。通过不同化学溶液侵蚀不同时间下灰岩的力学试验及分析,获得不同化学溶液侵蚀下龙门石窟灰岩强度损伤特性,建立化学溶液作用下灰岩单轴抗压强度随时间的侵蚀损伤方程。通过不同化学溶液侵蚀不同时间下灰岩溶解动力学试验及分析,研究灰岩在不同化学溶液中的溶解特性,建立化学溶液作用下灰岩侵蚀溶解动力学方程。试验分析研究表明,由于水化学溶液的溶解作用,化学溶液侵蚀下灰岩强度均有所下降。盐效应、同离子效应对灰岩溶解速率和强度的影响较大。盐效应提高灰岩溶解速率,同离子效应降低灰岩溶解速率。盐的种类和浓度均相同时,酸性越强,溶解速率越大;盐的种类和pH值相同时,盐浓度升高,灰岩溶解速率增大。研究结果将为石质文物及岩石工程的长期保护提供重要的理论基础,具有广泛的实际工程应用价值和应用前景。 相似文献
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热液成矿作用动力学研究进展 总被引：1，自引：0，他引：1
地球化学动力学 介于地球化学，化学动力学，流体力学之间的一门边缘学科。成矿作用动力学是地球化学动力学的重要分支，主要研究成矿作用的速度，机制和过程。目前在成在动力学研究过程中已出现成矿作用动力学，成矿地质地球化学动力学，构造动力成矿等方向。 相似文献
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粘土矿物转化的化学动力学模型与应用 总被引：11，自引：4，他引：11
本文讨论了粘土矿物转化的化学动力学模型及其应用。对于某一地区，粘土矿物蒙皂石向伊利石的转化主要受温度和时间的影响，可以用化学动力学一级反应的模型描述，这一模型可用于:（１）反演古大地热流；（２）模拟成岩史；（３）在盆地内没有钻井的区域预测地层的成岩阶段。 相似文献
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鄂尔多斯盆地北部古风化壳岩石-流体反应动力学模拟研究 总被引：3，自引：0，他引：3
古风化壳在油气储集、运聚中占重要地位，如华北、鄂尔多斯、塔里木盆地等地区重要油气藏的形成，与其碳酸盐岩顶部古风化壳密切相关。综合应用流体动力学、化学动力学及化学热力学理论，对古风化壳风化期岩石-流体相互作用过程动态模拟，重现古风化壳风化期流体动力场和化学动力场，从而达到定量预测古风化壳风化期物性参数（如孔隙度、渗透率等）变化的目的，最终为储层定量评价提供参数。岩石-流体反应动力学模拟是通过计算机对岩石与流体相互作用过程作一个动态再现，具有重要理论价值与实际意义 相似文献
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溶质在土工合成衬垫（GCL）长期入渗过程中具有明显的化学-渗透特性。室内渗透试验表明：阳离子之间的置换效应对GCL衬垫渗透系数影响较大,10 mM的CaCl2溶液使渗透系数上升至2.5×10-11 m/s,而30 mM的CaCl2溶液使渗透系数上升至5.6×10-11 m/s。渗透液体浓度的增加缩短了溶质穿透GCL的时间,且预饱和处理试剂对GCL渗透系数的变化影响较大,采用蒸馏水作为预饱和试剂处理GCL衬垫对其渗透系数的影响明显小于CaCl2溶液;建立了考虑膜效应和离子交换效应条件下溶质运移耦合动力学模型,并对GCL穿透试验过程中溶质浓度的变化进行了预测,仿真计算结果表明,10 mM和30 mM两种CaCl2溶液渗透条件下,Ca2+浓度变化的试验结果和计算结果均相吻合,验证了耦合动力学模型的可靠性;从Ca2+浓度及流量穿透曲线分布可知,化学-渗透效应可有效地延缓溶质的迁移速度。随着溶质浓度的降低,阻滞作用更显著。因此,在分析GCL衬垫中溶质入渗特征时,必须考虑化学-渗透效应的影响。 相似文献
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回顾了地球化学动力学这门新兴学科的产生与发展，评述了国内外矿物-水反应的地球化学动力学研究的新进展，介绍了矿物-水反应的溶解动力学及地球化学动力学模拟的新成果及应用领域。低温条件下硅酸盐和碳酸盐矿物与水的反应得到高度重视。硅酸盐矿物的溶解速率与溶液的pH值、离子强度、温度及有机酸的含量等密切相关。碳酸盐类矿物的溶解速率主要取决于温度、GO2分压、酸碱度及相关离子的活度等因素。氧化物、硫化物、及氟化物等的溶解沉淀的动力学研究开始得到关注。矿物-水反应的地球化学动力学模拟已成为一个很有前景的方向。 相似文献
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A numerical study of mechanical behavior of a cement paste under mechanical loading and chemical leaching 
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下载免费PDF全文 Based on relevant experimental data of a petroleum cement paste under mechanical loading and chemical leaching, an elastic‐plastic model is first proposed by taking into account plastic shearing and pore collapse. The degradation of mechanical properties induced by the chemical leaching is characterized by a chemical damage variable which is defined as the increase of porosity. Both elastic and plastic properties of the cement paste are affected by the chemical damage. The proposed model is calibrated from and applied to describe mechanical responses in triaxial compression tests respectively on sound and fully leached samples. In the second part, a phenomenological chemical model is defined to establish the relationship between porosity change and calcium dissolution process. The dissolution kinetics is governed by a diffusion law taking into account the variation of diffusion coefficient with calcium concentration. The chemical model is coupled with the mechanical model, and both are applied to describe mechanical response of cement paste samples subjected to progressive chemical leaching and compressive stresses. Comparisons between experimental data and numerical results are presented. 相似文献
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化学侵蚀下硬脆性灰岩变形和强度特性的试验研究 总被引：1，自引：0，他引：1
通过硬脆性灰岩在不同pH值、0.1 mol/L和Na2SO4和CaCl2溶液以及蒸馏水浸泡后的的常规三轴压缩试验,分析了受化学腐蚀作用的灰岩在不同围压下的变形及强度特性,探讨了三轴强度参数及变形参数的变化规律,并对浸泡岩石的化学溶液进行水质检测,得到了化学溶液中各离子浓度的变化规律,初步分析了化学溶液对灰岩力学特性影响的机制和规律。试验表明：化学溶液浸泡后,灰岩有从脆性向延性转化的趋势;灰岩的强度参数 , 值及弹性模量E均有不同程度的下降,而泊松比则增大;在相同的化学溶液侵蚀下,弹性模量和凝聚力降低幅度最大;灰岩力学参数劣化的程度与从灰岩中溶出的离子浓度的大小具有一定的对应关系：从灰岩中溶出的离子浓度越高,其力学参数劣化程度越大。 相似文献
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The dissolution process of the rock salt is actually a complicated process in fluid dynamics and chemical kinetics; therefore, the mathematical model for the solute-fluid flow during the cavern building may be established to research the change rule of the form of the cavern boundary based on the kinetic analysis of the convection–diffusion process, with integration of the basic theories of fluid mechanics and the principles of chemical kinetics. In order to research the dissolution mechanism of the rock salt under the condition of dynamic water, the method of numerical simulation has been employed to simulate and study the factors with effect on the fluid transport mechanism in solution mining cavern of the rock salt, and its dissolution in dynamic water has been simulated and researched. The result shows that the model established in this paper may well describe the dissolution process of rock salt under the condition of dynamic water, providing basic analyzing means for the research on the rock salt dissolution in dynamic water. 相似文献
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The complexity of alluvial-pluvial fan depositional systems makes the detailed characterization of their heterogeneity difficult, yet such a detailed characterization is commonly needed for construction of reliable groundwater models. Traditional models mainly focus on using a single aquifer property to qualitatively or semi-quantitatively characterize the heterogeneity of aquifer, so that they are unable to quantitatively reflect the synthetic heterogeneity of all aquifer properties. In this paper, we propose the heterogeneity synthetic index (HSI) for quantitative characterization of synthetic heterogeneity of an aquifer. The proposed calculation process involves four steps: (1) estimation of the hydraulic conductivity of a sediment sample using the cloud-Markov model, (2) establishment of the sedimentary microfacies distribution model through the Markov chain, (3) characterization of the distribution model of hydrogeological parameters using the improved sequential simulation method according to the “facies-controlled modeling” technique, and (4) application of the entropy weight method to calculate the weight coefficient of the above aquifer properties. The HSI of an aquifer is calculated by superposition of these models according to the corresponding weight coefficient. This approach was applied to the Luancheng aquifer deposit in the southeast Hutuo River alluvial-pluvial fan in the North China Plain (NCP). The results have demonstrated that aquifer 3 which was formed in the middle Pleistocene has the strongest heterogeneity, with an HSI of 0.25–0.75. Aquifer 4 formed in the early Pleistocene shows an intermediate heterogeneity, with the HSI ranging 0.35–0.75. The weakest heterogeneity was found in aquifers 1 and 2 formed in the Holocene and late Pleistocene, with HSI values of 0.40–0.75 and 0.40–0.80, respectively. The heterogeneity of all the four aquifers is relatively strong in the radial direction of the Huai River alluvial-pluvial fan due to the abrupt change of microfacies. In contrast, in the radial direction of the Hutuo River alluvial-pluvial fan, the microfacies change mildly, and the continuity of hydrogeological parameters is better, which has resulted in weaker heterogeneity of the four aquifers in this direction. Findings suggest that the sedimentary environment has significant effects on the aquifer heterogeneity. Considering that there are many aquifer properties, HSI can quantitatively characterize the synthetic heterogeneity of the aquifer and describe the influence of each aquifer property on the synthetic heterogeneity of the aquifer according to its weight coefficient. Thus the HSI approach can be successfully used to deal with the spatial heterogeneity of aquifer and provide a foundation for studies on contaminant transport. 相似文献
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岩溶作用时间尺度与碳汇稳定性 总被引：7，自引：3，他引：4
从碳酸盐溶蚀快速动力学过程、岩溶动力系统的开放性、环境敏感性和生物参与性等方面分析了岩溶作用过程的时间尺度及其碳汇稳定性,指出岩溶碳循环是一种兼具不同时间尺度的特殊地质作用过程,因水生植物和土地利用变化的影响,碳汇效应显著且相对稳定,仍对现今大气CO2减排有重要意义。为更好地估算岩溶碳汇潜力,在加强高精度自动化监测的同时,需要考虑外源水、水生植物及土地利用变化等因素。 相似文献
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《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》1999,24(10):861-870
Weathering rates based on temporal changes in a variety of rock properties were examined for four dated lava domes made of porous rhyolite. The lava domes were erupted at 1.1, 2.6, 20 and 40 ka BP. The time from each eruptive event to the present provide elapsed weathering times. The lava domes have many cooling joints formed immediately after eruption. Joint-bounded blocks have a high porosity, resulting in deep weathering. The blocks have almost uniform characteristics from top to bottom in one outcrop. The mineralogical, chemical, physical and mechanical properties of the four rhyolites were analysed. These results show that the chemical properties and physical properties, including specific surface area, change slowly in the early stage of weathering (0–20,000 years) and quickly in the later stage (20,000–40,000 years), while mechanical strength and bulk density or porosity of the rhyolites change rapidly in the early stage and slowly in the later stage. Mechanical strength reduces by 70–90% relative to fresh rock in 40,000 years, although chemical and physical properties change by only 1023̄0 %. It is concluded that different weathering properties exhibit different rates and patterns of change over 40,000 years, and that mechanical strength is the property most susceptible to weathering. 相似文献
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水-岩化学作用等效裂纹扩展细观力学模型 总被引：2，自引：0，他引：2
从化学腐蚀下岩石细观结构的变化出发,研究水化学溶液对岩石中裂纹的腐蚀作用。运用地球化学矿物-水反应的溶解动力学,考查水-岩反应化学溶液中不同时间段离子浓度的变化,从理论上探讨化学腐蚀下等效裂纹扩展的定量化分析方法。通过质量守恒定律计算出裂纹在迹长及隙宽方向的变化,将水化腐蚀等效成有效裂纹长度,建立了水-岩化学作用下等效裂纹扩展的计算公式并计算应力强度因子。通过对砂岩的研究结果表明,水-岩化学作用对岩石裂纹的扩展有显著影响,并且具有时间效应。同时,水化学溶液的离子浓度及pH值大小对裂纹的扩展存在影响,其中pH值的变化对岩石的断裂力学效应更加显著。当溶液的酸性越强或碱性越强,腐蚀越大,裂纹扩展越快;pH值为中性时,腐蚀作用得到较大缓解,裂纹发展缓慢。为定量研究裂隙岩体在水岩化学作用下的细观机理提供了一种新的思路。 相似文献
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河北平原深层碱性淡水形成的水文地球化学模拟——以保定、沧州地区为例 总被引：4，自引：0，他引：4
以揭示河北平原深层碱性淡水化学形成机制为主要研究目的, 选择河北平原深层碱性淡水发育的保定、沧州地区为典型研究区, 应用水文地球综合分析方法和地下水地球化学模拟技术, 探讨了深层碱性淡水水化学性质、分布规律及形成的自然环境; 依据质量守恒原理建立深层地下水质量平衡反应模型, 研究了从山前至滨海整个水流路径上所发生的水文地球化学作用及水、岩间的质量交换, 从而揭示了深层地下水化学演化规律的内涵及深层碱性淡水水化学形成机制.主要结论是深碱性淡水是由山前补给区HCO3-Ca·Mg水逐步演化而来, 从山前至中部平原, 在地下水环境由开放转为封闭的过程中, 方解石、白云石溶解和沉淀, 钠长石、石膏、岩盐和菱铁矿的溶解, Ca-Na阳离子交换是控制其形成和演化的主要水文地球化学作用. 相似文献
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Darcys Law Expressed by Chemical Index 总被引：3，自引：0，他引：3
Hu Kuanrong Cao Yuqing Zhang Wenbing Hu Zhongyi Department of Hydrogeology Engineering Geology Changchun University of Science Technology Changchun 《中国地质大学学报(英文版)》2000,11(4)
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