西南某水电站坝基岩体质量分级研究

坝基岩体质量分级关系到大坝工程的安全性和经济性.通过对坝基岩体质量分级要素及各要素之间的联系进行研究,得出岩体分级各要素界限指标的对应值.在此基础上提出适用于本工程坝基岩体质量分级的单因素和双因素标准.并应用此标准对该坝基进行岩体质量分级.     

Well placement optimization with the covariance matrix adaptation evolution strategy and meta-models

The amount of hydrocarbon recovered can be considerably increased by finding optimal placement of non-conventional wells. For that purpose, the use of optimization algorithms, where the objective function is evaluated using a reservoir simulator, is needed. Furthermore, for complex reservoir geologies with high heterogeneities, the optimization problem requires algorithms able to cope with the non-regularity of the objective function. In this paper, we propose an optimization methodology for determining optimal well locations and trajectories based on the covariance matrix adaptation evolution strategy (CMA-ES) which is recognized as one of the most powerful derivative-free optimizers for continuous optimization. In addition, to improve the optimization procedure, two new techniques are proposed: (a) adaptive penalization with rejection in order to handle well placement constraints and (b) incorporation of a meta-model, based on locally weighted regression, into CMA-ES, using an approximate stochastic ranking procedure, in order to reduce the number of reservoir simulations required to evaluate the objective function. The approach is applied to the PUNQ-S3 case and compared with a genetic algorithm (GA) incorporating the Genocop III technique for handling constraints. To allow a fair comparison, both algorithms are used without parameter tuning on the problem, and standard settings are used for the GA and default settings for CMA-ES. It is shown that our new approach outperforms the genetic algorithm: It leads in general to both a higher net present value and a significant reduction in the number of reservoir simulations needed to reach a good well configuration. Moreover, coupling CMA-ES with a meta-model leads to further improvement, which was around 20% for the synthetic case in this study.     

A Case Study on the Occurrence and Mobility of the Shale Oil from the Muli Coalfield, Qilian Mountain

正Objective Shale oil occurs in free state(including condensate state),adsorption state(adsorbed on kerogen and mineral particles)and dissolved state(dissolved in natural gas,residual water,etc.)in shales and adjacent layers.The characterization of the occurrence of different hydrocarbons in shale oil,especially the quantitative     

西北黄土地区地铁深基坑工程监测的关键技术

根据西北黄土地区第一条地铁——西安地铁近四年地铁基坑工程的监测经验,提出了基坑工程监测的主要内容、作用及其常用监测手段,介绍了轴力监测关键技术;测斜仪量测墙体位移关键技术;地裂缝段地表监测点布设的关键技术;盾构地表监测作用、监测项目、地层移动特征;监测报警注意事项。其中着重分析了黄土地区常用的内支撑形式——钢支撑监测的注意事项及常见异常测量数据的出现原因,提出温度对其测量结果的影响不可忽略。     

Formation and Evolution of a Paleosol across the Lower Silurian-Lower Permian Boundary in Zunyi District, Northern Guizhou, China and Its Paleoenvironment and Paleoclimate Implications

This paper presents a set of bulk geochemical and mineralogical data from a paleoweathering profile located in Zunyi District, Northern Guizhou, China. It was formed at the top of the Hanjiadian Formation of the Lower Silurian. A truncated, argillic, gleyed, kryptic paleospodosol is recognized in the paleoweathering profile. Ratios of immobile elements (Ti/Zr, Ti/Al) and their binary (e.g., Nb vs. Zr/TiO2 and Th/Sc vs. Zr/Sc), triangular diagrams (La-Th-Sc, Th-Sc-Zr/10, Zr-Cr-Ga) reflect that the Gaojiayan paleosol is the product of in-situ weathering of gray-green silty mudstone of the underlying Hanjiadian Formation. Mass balance calculations indicate K enrichment and Na enrichment in the upper and lower portions of paleosol, respectively. These findings both are the results of transgression, which brings substantial concentrations of such elements as K, Na, and Sr. In particular, K enrichment is achieved by the illitization of kaolinite. The biological processes of terrestrial vascular plants also enhance K concentration, especially at the top of the paleosol. Na enrichment is a consequence of albitization and/or adsorption by clay minerals through cation exchange. The mass distributions and relative mass changes of rare earth elements (REEs) in the studied profile display characteristics of vertical zonation. Three peaks in total REEs content are observed, indicating two paleoclimatic or paleoenvironmental changes. Mineralogical characteristics indicate that the paleoclimate changed first from warm and humid to cold and dry and later, to dry and lightly warmer. The corresponding soil environment varies from weakly acidic to strongly alkaline and later, to weakly acidic. Mass translocation characteristics of REEs and several transition metals suggest that the Gaojiayan paleosol may have undergone top erosion.     

汇聚板块边缘岩浆中金属和氯的地球化学性质研究

总结了铜(Cu)、金(Au)、铼(Re)和氯(Cl)在汇聚板块边缘岩浆中的性质。在岛弧型的火山岩岩浆演化的早期,Cu、Au和Re均表现为中度不相容元素,含量随SiO2含量的增加而增加。在SiO2质量分数为58%时,多数岛弧型火山岩中Au、Cu的含量会突然大幅度下降。这一变化与铁和钛的变化是耦合的,铁和钛均由不相容元素变为相容元素,显示钛磁铁矿开始结晶了。进一步的研究表明,钛磁铁矿的结晶使硫酸根被还原为氢硫酸根,后者与Au、Cu形成氢硫酸根络合物,被萃取到流体相中,从而形成成矿流体。这一过程可以很好地解释Au、Cu矿床广泛分布于汇聚板块边缘的现象。与Au、Cu相反,Re的含量在SiO2质量分数为60%时才开始下降,而且是缓慢下降。这是因为Re通常比Au、Cu更亲石。此外,Re还具有强烈的挥发性。氯在东Manus岩浆中表现为高度不相容的特点。氯的性质主要受压力、初始水含量和岩浆演化分异程度的控制。计算结果显示,由于MORB和OIB含水量低,分异演化程度低,氯在上述岩浆中表现为高度不相容的特点。相比之下,氯在岛弧岩浆中的性质就复杂得多。随着水含量和岩浆房深度的不同,氯的性质可以从相容变到高度不相容。     

库姆塔格沙漠的“羽毛状沙丘”形态的观测

参照卫星照片和地形图,实地观测了库姆塔格沙漠“羽毛状沙丘”分布区域的地貌。新月型“沙垄”是该区域的主导性地貌类型,垄间地形波状起伏。如果将“沙垄”喻为“羽轴”,垄间的波状起伏地形为“羽枝”,则可构成卫星照片所显示的“羽毛状沙丘”。新月型“沙垄”的走向为NE-SW,由新月形沙丘前一沙丘的迎风坡与后一沙丘的东翼相连而成,高3~19m,宽约50m,长15~22km。“垄”间起伏地形的波长为100~300m,振幅为40~100cm,与“沙垄”成60~105°夹角。在波状起伏地形的波峰与波谷过渡区堆积颜色较浅的细沙,厚2~7cm,构成了“大沙波”。实地观测的“羽毛状沙丘”的形态与卫星照片显示的形态有一定差异。     

印度尼西亚弗洛勒斯海LGM以来的古海洋学记录

弗洛勒斯海位于印度尼西亚穿越流通道上,它的古海洋学特征对于理解LGM以来穿越流活动历史,及其与全球气候变化的关系具有重要意义．通过对弗洛勒斯海SHI9011岩心δ^18O、δ^13C浮游有孔虫组合及碳酸盐含量等古海洋学记录的研究,认为研究区沉积速率不高,生物生产力却并不低于高沉积速率的近陆地区．冰期时海平面下降,陆源物质输入量增加,使得古生产力上升．冰消期终止期IA海平面快速上升,陆源营养物质供应减少,同时穿越流活动增强,抑制了下部水体向上运动,古生产力开始下降．8～6ka前后,强烈的东南季风使得研究区上升流活动增强．     

地幔流体及其成矿作用

地幔流体作为一种重要成矿介质在某些矿床形成过程中起到过重要作用。根据目前地幔流体研究的某些成果，介绍了地幔流体可能与成矿的方式和成矿机制，并举例说明地幔流体与超大型，大型矿床之间的成因联系。