Rock Mass Characteristics in Beishan, A Preselected Area for China’s High-Level Radioactive Waste Disposal     

WEI Xiang  GUO Ying  CHENG Hanlie  MENG Xiangdong  CHENG Mingqian  YANG Ting  XU Chunmei 《《地质学报》英文版》2019,93(2):362-372

Geological and hydrological characteristics, joint geometric features, rock physical and mechanical properties and rock mass quality are studied in the Beishan area, preselected for China’s high-level radioactive waste (HLW) disposal engineering. A comprehensive survey method is developed to study joint geometric features in the outcrop and samples from borehole BS06 into the Xinchang rock mass were tested. The optimal joint sets are determined by rose diagrams and equal-area lower hemisphere plots of joint poles. Results show that: 1) the distribution of joint occurrence obeys a normal distribution, while the distribution of joint spacing obeys a negative exponential distribution; 2) concentric circular and tangent circular sampling windows are applied to study the trace length and the trace midpoint density. Results indicate that tangent circular sampling window is more stable and reasonable; 3) Beishan granite shows high density, low porosity and high strength based on many laboratory tests and the physical properties and mechanical properties are closely related; and 4) a synthesis index, Joint Structure Rating (JSR), is applied to evaluate the quality of rock mass. Through the research results of rock mass characteristics, the Xinchang rock mass in the Beishan preselected area has the favorable conditions for China’s HLW disposal repository site.  相似文献   

水文双变量重现期分析及在干旱中应用          下载免费PDF全文

周平  周玉良  金菊良  蒋尚明  吴成国 《水科学进展》2019,30(3):382-391

单变量水文统计中一些广为接受的概念在多变量环境下尚缺乏深入分析,也易被误解,如N年内重现期大于等于T的多变量事件发生的次数与N/T的关系。实践中,多变量联合重现期与其边缘分布变量重现期的一些经验关系被发现并通过了案例验证分析,但缺乏解释和推导。基于GH Copula推导了双变量联合重现期与边缘分布变量重现期的关系以及双变量事件发生次数与其重现期、变量相关程度间的定量关系。以昆明56年的逐月SPI(Standardized Precipitation Index)和SRI(Standardized Runoff Index)识别了干旱事件,采用GH Copula构建了干旱历时和烈度的联合分布函数,验证了双变量联合重现期与边缘分布变量重现期的关系以及多变量事件发生次数与其重现期的定量关系。表明不宜以“and”第1重现期是否接近于比该干旱事件的旱情更重的干旱发生的平均时间间隔来说明干旱特征值重现期分析的合理性。变量的相关性不强时,需谨慎采用边缘分布变量重现期的较大值近似代替“and”事件的第1重现期。  相似文献   

川南煤田龙潭组煤系泥页岩气与煤层气组合模式及合采前景分析     

尹中山  蒋琦  熊建龙  罗勇  琚宜文 《中国煤炭地质》2019,(5):30-35

文中研究的上二叠统龙潭组煤层及其顶底板泥页岩含气性特征、组合模式及合采对煤系气勘探开发意义重大。为改变煤层气产业低产低效长周期的现状,实现综合效益的目标,将龙潭组作为目标层进行研究;简述了川南煤田龙潭组含气泥页岩与煤层的组合模式,并初步探讨了上述组合模式合探合采的必要性、条件和前景,并提出了开展综合勘探开采的建议。  相似文献   

物化探综合信息找矿方法在萤石矿找矿中的应用     

栗克坤  陈新立  商朋强  于雪良  韩志坤  魏凡超  刘增政 《中国地质调查》2019,6(6):98-104

福建光泽地区是闽北地区重要的萤石矿成矿远景区,具有寻找隐伏—半隐伏萤石矿的潜力,但是目前该区隐伏—半隐伏萤石矿找矿成果较少。通过对福建光泽地区I号萤石矿预测区开展物化探综合信息找矿方法应用,探讨物化探综合信息找矿方法在隐伏—半隐伏萤石矿找矿中的应用效果。结果表明: 区域水系沉积物测量和大比例尺化探剖面测量圈出的F、Ca等综合异常信息可协助筛选、确定萤石矿找矿目标区; 将高精度磁法测量与视电阻率联合剖面测量相结合,可进一步判断萤石矿控矿构造的位置和规模; 高密度电阻率法测量可协助确定控矿构造的深部延伸情况。地表检查和深部钻探验证表明: 区域化探、高精度磁法测量、视电阻率联合剖面测量和高密度电阻率法测量等物化探综合信息找矿方法组合,可指导隐伏—半隐伏萤石矿的找矿工作。  相似文献   

Numerical evaluation of soft inter‐slab joint in concrete‐faced rockfill dam with dual mortar finite element method          下载免费PDF全文

Mozhen Zhou  Bingyin Zhang  Chong Peng 《国际地质力学数值与分析法杂志》2018,42(5):781-805

Recently constructed concrete‐faced rockfill dams (CFRDs) often use soft inter‐slab joints to prevent axial compression‐induced extrusion damage in the concrete face. Due to the complexity of the multibody contact and the lack of information on the actual behavior of soft joints, it is highly challenging to numerically assess the effect of soft joints in CFRDs. In this paper, we present a numerical approach for the three‐dimensional modeling of CFRDs with hard and soft joints. A dual mortar finite element method with Lagrange multiplier is developed to treat the multibody contact in hard joints with impenetrability condition. The soft joint slab‐filler‐slab contact system is modeled using an equivalent contact interface approach, where the soft contact constraints are imposed using a perturbed Lagrange formulation. Through a series of laboratory tests, the mechanical behavior of soft joint is investigated. An extrusion model for the soft joint is presented and implemented in the dual mortar finite element method. The proposed numerical method is applied to the three‐dimensional analysis of Tianshengqiao‐1 CFRD. Despite the complex multibody contact and strong material and geometry nonlinearities in the CFRD, the proposed method is stable and capable of capturing salient characteristics of the CFRD. Numerical results show that in Tianshengqiao‐1, the employment of soft joints can effectively reduce the axial compression stress, thus greatly alleviating the risk of extrusion damage in the concrete face.  相似文献   

松辽盆地东缘营城组节理构造特征、分布规律及其储层预测     

孙庆春  孙晓猛  王璞珺  刘万洙  金凤兰  白雪峰 《吉林大学学报(地球科学版)》2007,37(6):1091-1096

首次较系统地统计了研究区节理产状、规模、开度、密度以及分布规律,阐述了其储层意义。根据节理产出层位、切割关系和区域构造背景分析,将研究区节理的形成期次划分为营城期、营城末期和晚白垩世晚期3个期次。利用共轭节理产状和节理面性质,计算出营城期具有近东西向伸展和挤压相互交替的构造应力场;营城组末期具有NE—SW向挤压构造应力场;晚白垩世晚期具有NW—SE向挤压构造应力场。营城组中的节理形成与分布主要与前两期挤压应力场有关。在此基础上,对徐家围子地区营城组节理分布规律进行了预测,为天然气储层分布规律研究提供可视化对比依据。  相似文献   

基于最小能耗的海洋浮式平台位置轨迹优化     

靳其宝  李英华 《广东海洋大学学报》2021,(1)

【目的】研究解决海洋大惯量浮式平台在复杂海况影响下所引起的振动冲击问题。【方法】采用逆运动学分析方法对平台回转位置进行优化研究,提出一种基于关节最小耗能的多目标轨迹优化算法。采用分段样条插值方法构造关节位置曲线,并建立关节能耗轨迹优化模型,采用粒子群算法实现对关节位置的优化搜索,从而得到基于平台转动最小耗能的位置优化轨迹。【结果与结论】所采用的轨迹优化方法能有效改善系统运行的平滑性,降低回转机构振动与冲击的影响程度,可为平台的振动与冲击主动控制提供必要的理论依据。  相似文献   

伸缩缝刚度对大跨度悬索桥动力特性的影响   总被引：1，自引：1，他引：0  

严琨  王立新  姜慧 《震灾防御技术》2017,12(3):667-676

伸缩缝作为大跨度桥梁与引桥之间的重要连接构件,其抗推刚度及可能存在的变异性对主桥及引桥动力特性的影响不可忽略。本文建立了大跨度悬索桥及引桥的有限元模型,采用弹簧单元模拟加劲梁与引桥箱梁之间的伸缩缝,分析伸缩缝刚度对悬索桥及引桥自振特性及其地震响应的影响规律。分析结果表明:伸缩缝刚度对加劲梁的横弯振型、竖弯与纵飘耦合振型的频率有明显的影响;伸缩缝刚度的变化会导致加劲梁与引桥的振型相互耦合,同时这些振型的频率发生相应的突变,当伸缩缝刚度较大时,加劲梁两个竖弯与纵飘的耦合振型解耦成为独立的竖弯和纵飘振型;当引桥与悬索桥加劲梁的纵飘振型发生耦合时,在纵向和竖向地震作用下的悬索桥及引桥的地震响应达到最小。伸缩缝刚度对悬索桥动力特性影响的分析可为悬索桥的模态参数确认、损伤识别、抗震性能分析提供有价值的借鉴。  相似文献   

Non‐linear seismic response of arch dams with contraction joint opening and joint reinforcements     

Chuhan Zhang  Yanjie Xu  Guanglun Wang  Feng Jin 《地震工程与结构动力学》2000,29(10):1547-1566

A comprehensive study of non‐linear seismic response of arch dams with contraction joint opening and joint reinforcements has been conducted. A numerical model of contraction joint reinforcements is presented for optimization control of the joint opening. The objective of this control is to reduce the joint opening and expectantly to balance the sustained loads between the horizontal and the vertical components of the dam, thus avoiding an overstress in the cantilever while retaining the release of arch tensile stresses to some extent. Several parameter studies such as critical element size and required number of joints to be simulated for convergence are also performed. As an engineering application, a 292‐m high arch dam (the Xiaowan arch dam) and the Big Tujunga dam are analysed in detail. The results demonstrate that the joint opening and the corresponding load transfer from the arch to cantilever components of the dam during strong earthquakes are substantial. It is also evident that by providing sufficient strength and reinforcement flexibility, the joint opening can be controlled to some extent. However, the stress redistribution due to reinforcement control is not sufficient to avoid the overstress in the cantilever for the Xiaowan arch dam. Thus, alternative measures are discussed. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

工程建设项目的多测整合对策研究     

王楠  李穗浓  张郁  吴辉 《地理空间信息》2022,20(2):156-158

以广州市开展联合测绘的改革成效为基础,进一步探索研究工程建设项目审批服务全链条中的测绘服务事项,重点关注优化测绘服务流程、统一测绘技术标准规范、强化对测绘成果的共享互认以及完善测绘行业管理制度等内容,通过优化测绘服务体系为审批制度改革"加速",为优化营商环境"助力",为全国各地全面推出"多测合一"改革提供可复制推广的经...  相似文献