湿化膨胀与掺砂率对混合型缓冲材料THM耦合过程的影响分析     

魏天宇  王旭宏  吕涛  胡大伟  周辉  洪雯 《岩土力学》2022,(2)

加入辅助骨料后的混合型缓冲材料在保留了材料密封和防渗能力的同时,克服了纯膨润土导热系数低、施工性差的缺点,作为高放废物处置库缓冲材料的备选材料正在成为新的研究热点。基于室内试验数据,以多孔介质非饱和渗流理论为基础,考虑了膨润土湿化膨胀及密度、饱和度、导热系数等材料物理性质参数的实时变化,利用COMSOL Multiphysics软件建立了包含一条巷道及单个井孔的3D网格模型,计算模拟了100 a间屏障系统中膨润土-石英砂混合型缓冲材料的THM多场耦合演化过程,分析了各物理量的时间演化及空间分布规律,并通过不同工况分析了材料湿化膨胀以及掺砂率对屏障系统演化过程的影响。系统中材料温度、饱和度与距固化体、岩壁的距离呈相关性,应力整体以受压为主,变形呈先压缩后膨胀的趋势。其中,膨润土基材料的湿化膨胀作用对温度演化的影响很小,但会略微加速饱和进程,并使材料的应力-应变出现明显的时间演化及区域分布差异。井孔和巷道中靠近岩壁区域的应力上升较快,并且在巷道底板与井孔交界处出现了显著的竖向位移。提高掺量可以有效降低罐体表面温度,增强屏障系统散热能力,降低缓冲材料的历史最大应力,有效控制井孔轴线上的竖向位移,但也会削弱系统的防渗能力。  相似文献   

Nano-art,dynamic matter and the sight/sound of touch     

《Geoforum》2014

This paper offers an auto-ethnographic account of Midas, an immersive bio-media installation created by artist Paul Thomas. The experiences of the installation provide a stepping-off point for a discussion of the corporeal geographies and the nano-imaginaries that the work develops. Understanding the senses as a principle means whereby the body mingles with the world and with itself, we begin from a focus on Midas’s presentation of the inter-relations of touch, vision and hearing, thereby extending geographical thinking on aurality, but also reworking the immersive geographies that are implicated within ontologies of touch. We draw out these geographies by way of the depths and passages of Irigaray’s (1993) fluid ontology of touch. From here we explore the ‘creative rethinking’ of matter that the installation develops, exploring the organismic topographies that it develops which stand against nano-imaginaries of matter that are focused either on the corporeal violence of nano-splatter, or the understanding of nanotechnologies through the mastery and control of matter.  相似文献   

A parallel,fully coupled,fully implicit solution to reactive transport in porous media using the preconditioned Jacobian-Free Newton-Krylov Method     

《Advances in water resources》2013

Modeling large multicomponent reactive transport systems in porous media is particularly challenging when the governing partial differential algebraic equations (PDAEs) are highly nonlinear and tightly coupled due to complex nonlinear reactions and strong solution-media interactions. Here we present a preconditioned Jacobian-Free Newton-Krylov (JFNK) solution approach to solve the governing PDAEs in a fully coupled and fully implicit manner. A well-known advantage of the JFNK method is that it does not require explicitly computing and storing the Jacobian matrix during Newton nonlinear iterations. Our approach further enhances the JFNK method by utilizing physics-based, block preconditioning and a multigrid algorithm for efficient inversion of the preconditioner. This preconditioning strategy accounts for self- and optionally, cross-coupling between primary variables using diagonal and off-diagonal blocks of an approximate Jacobian, respectively. Numerical results are presented demonstrating the efficiency and massive scalability of the solution strategy for reactive transport problems involving strong solution-mineral interactions and fast kinetics. We found that the physics-based, block preconditioner significantly decreases the number of linear iterations, directly reducing computational cost; and the strongly scalable algebraic multigrid algorithm for approximate inversion of the preconditioner leads to excellent parallel scaling performance.  相似文献   

Flow-Induced Vibration Fatigue Damage of A Pair of Flexible Cylinders in A Staggered Array     

Xu  Wan-hai  Li  Yu-han  Jia  Kun  Lai  Jiang 《中国海洋工程》2021,35(6):878-890

China Ocean Engineering - Flow-induced vibration (FIV) of a group of long, flexible cylinders involves a complex interaction between fluid and structures. Although a substantial number of studies...  相似文献   

Observation system simulation experiments using an ensemble-based method in the northeastern South China Sea     

Geng  Wu  Cheng  Feng  Xie  Qiang  Zou  Xiaoli  He  Weihong  Wang  Zhaozheng  Shu  Yeqiang  Chen  Gengxin  Liu  Danian  Ye  Dong  Wang  Ruiwen  Liu  Chuanyu 《中国海洋湖沼学报》2020,38(6):1729-1745

Journal of Oceanology and Limnology - An ensemble-based method for the observation system simulation experiment (OSSE) is employed to design optimal observation stations and assess the present...  相似文献   

MODIS和HJ-1 CCD数据时空融合重构NDVI时间序列     

孙锐  荣媛  苏红波  陈少辉 《遥感学报》2016,20(3):361-373

遥感数据反演高时空分辨率NDVI对监测植被动态变化过程具有重要意义,然而受天气影响,单颗卫星难以提供时间连续的高空间分辨率NDVI数据。以华北平原中东部为实验区,联合HJ-1 CCD数据和MODIS数据,对STARFM算法进行了改进,(1)考虑了不同地物对光谱响应的差异,为减少分类错误利用统计学上()对分类数据进行筛选,按照不同地物类型分别利用线性拟合方法修改光谱距离权重;(2)定义了预测半径,对HJ-1 CCD数据因外界影响而缺失的影像进行了预测。结果表明,与真实影像相比,预测结果呈现了较好的空间一致性,相关系数均达到了极显著相关,改进算法的预测精度要高于原算法。利用该方法将HJ-1 CCD NDVI的空间变化信息与MODIS NDVI时间变化信息有机结合重构了高时空分辨率NDVI序列,有效补充了HJ-1CCD NDVI的缺失数据集。  相似文献   

Multi-objective Optimization of Geothermal Extraction from the Enhanced Geothermal System in Qiabuqia Geothermal Field, Gonghe Basin     

SONG Guofeng  SONG Xianzhi  LI Gensheng  XU Ruin  CAO Wenjiong  Zhao Chenru 《《地质学报》英文版》2021,95(6):1844-1856

A geothermal demonstration exploitation area will be established in the Enhanced Geothermal System of the Qiabuqia field, Gonghe Basin, Qinghai–Xizang Plateau in China. Selection of operational parameters for geothermal field extraction is thus of great significance to realize the best production performance. A novel integrated method of finite element and multi-objective optimization has been employed to obtain the optimal scheme for thermal extraction from the Gonghe Basin. A thermal-hydraulic-mechanical coupling model (THM) is established to analyze the thermal performance. From this it has been found that there exists a contraction among different heat extraction indexes. Parametric study indicates that injection mass rate (Qin) is the most sensitive parameter to the heat extraction, followed by well spacing (WS) and injection temperature (Tin). The least sensitive parameter is production pressure (pout). The optimal combination of operational parameters acquired is such that (Tin, pout, Qin, WS) equals (72.72°C, 30.56 MPa, 18.32 kg/s, 327.82 m). Results indicate that the maximum electrical power is 1.41 MW for the optimal case over 20 years. The thermal break has been relieved and the pressure difference reduced by 8 MPa compared with the base case. The optimal case would extract 50% more energy than that of a previous case and the outcome will provide a remarkable reference for the construction of Gonghe project.  相似文献   

巴什布拉克含铀地沥青铀矿床矿化特征和成矿机理     

刘正义  许强  刘红旭  董文明  秦明宽  刘佳林  朱泉龙 《西北地质》2021,(1)

通过实地和显微镜观察、取样、分析测试等方法,取得大量实际资料,着重研究巴什布拉克矿床铀与石油产区含地沥青铀矿床之间等内在联系,利用所取得的大量数据对地沥青及其铀矿化特征和成矿机理予以讨论,认为巴什布拉克与石油密切相关的大型含地沥青铀矿床为一种既有承压水的层间氧化为主、又有潜水氧化,特别与石油热演化、油气破坏产物地沥青和油气还原(H2、CH4)、热液(水)蚀变、碳酸盐水洗、渗漏与扩散等因素有关的复成因类型。石油含铀和多金属,与其氧化为沥青增加对铀吸附性,以及存在还原性气体具有极强的还原铀能力有关,地沥青既具有在酸性介质中发生吸附铀,又能在弱碱性介质中还原铀的能力。  相似文献   

The equilibration of high-angle grain boundaries in dynamically recrystallized quartz: the effect of crystallography and temperature     

《Journal of Structural Geology》2002,24(6-7):1125-1137

Dynamically recrystallized and sutured quartz grains from metamorphic rocks with different strain intensities and temperature conditions ranging from ca. 350°C to ca. 700°C have been studied. Universal-stage measurements on quartz–quartz high-angle grain boundaries show that they are never curved but always consist of straight segments which preferentially occupy specific crystallographic orientations in relation to both neighboring crystals. With increasing temperature the segments preferentially concentrate in a decreasing number of orientations, mainly near the rhombohedral {101̄1} planes. The crystallographic data and the observations on grain boundary geometries suggest that: (i) grain boundary orientations are strongly crystallographically controlled, (ii) this control is the main factor on the textural equilibration of quartz–quartz grain boundaries in metamorphic rocks, and (iii) grain boundaries from dynamically recrystallized quartz should be regarded as annealed and equilibrated fabrics that are stable against subsequent annealing as long as the material is not re-deformed.  相似文献   

考虑地基辐射阻尼的结构静动综合响应计算     

何建涛  马怀发  陈厚群 《世界地震工程》2012,28(2):79-83

推导了便于工程应用的底边界同时入射三向地震波时地基底边界和四个侧边界相应于黏弹性边界的地震动输入公式;对目前静动力分析中边界条件不统一的解决方法进行了综述,分析了其合理性;由工程实例可以看出,由基本方法求得的结构最大主应力较直接用黏弹性动力边界求解静力问题的方法更加接近实际,而最大主应力往往控制着材料的损伤破坏,因此,虽然操作过程比较麻烦,但仍建议用基本方法求解结构的静动综合响应。  相似文献