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1.
随着城市轨道交通的快速发展,我国主要城市已开发较大规模的站域地下公共空间。然而,专门针对我国城市站域地下公共空间发展的理论研究较少,亦常缺乏时间维度的规律分析。本文以上海91处站域地下公共空间为例,深入剖析其时空发展规律与空间组织特征,为我国其他城市的地下空间开发提供借鉴。结果表明,潜在商业回报和TOD开发理念的推广是上海站域地下公共空间开发的重要动因,其时空分布规律与城镇化发展进程基本一致。城市区位、站点能级、站域空间开发水平是站域地下公共空间选址的重要影响因素。为保障地下空间连通规划的落地性,站域地下公共空间应避免采用站组域空间布局结构,应尽可能采用单级连通模式或以公共产权空间为连通媒介空间的多级连通Ⅰ类模式。  相似文献   

2.
The effects of uncertainty due to the variability of soil parameters on the risk of landsliding in the Himalayan region are investigated using a random field model combined with slope stability analyses. Effects of spatial variability both in horizontal and vertical directions, number of test samples, variations in piezometric level and the influence of earthquake on the reliability of a typical slope in a slide area are investigated. The results show that the reliability of slopes in the slide area is significantly affected by the coefficients of variation of soil parameters, spatial variations of soil parameters, number of test samples and piezometric variations. The results also show that the assumption of isotropic variations to assess slope reliability isconservative. The results of the study are useful in providing guidelines and pointing to remedial measures in the form of sub-surface drainage to improve slope reliability in the area.  相似文献   

3.
王春永 《地质与勘探》2024,60(3):433-457
以位于华北克拉通南缘的河南省熊耳山铁炉坪银多金属矿田为研究对象,通过对区内地质构造、成矿作用、物化探资料、遥感影像等综合研究,发现该矿田是一个与同构造隐伏花岗岩体有关的岩浆热液成矿系统。推测该隐伏岩体为一个东宽西窄、东厚西薄的“鞋底”状花岗质岩席,其总体空间形态与熊耳山变质核杂岩下盘的东向运动学方向密切相关。高位岩浆房的主体(隐伏岩体厚大部分)定位于故县水库以东地带。区内已发现的银、金多金属矿床主要是隐伏岩体东部主体顶上带外缘区定位的中温热液脉状矿化。推测在隐伏岩体顶上带的中南部还有三个隐伏岩钟发育部位,正是岩浆热液二次沸腾核心区域,因而是形成高温的斑岩型铜钼矿或隐爆角砾岩型钼金矿的最有利区段。  相似文献   

4.
Reibel  Michael  Glickfeld  Madelyn  Roquemore  Peter 《GeoJournal》2021,86(3):1337-1354
GeoJournal - This paper discusses the challenges facing urban water systems in disadvantaged communities (DACs) using Los Angeles County as a case study area. We review issues of water...  相似文献   

5.
This paper illustrates the computational benefits of polynomial representations for quantities in the likelihood function for the spatial linear model based on the power covariance scheme. These benefits include a comprehensive study of likelihoods and maximum likelihood estimators for data. For simplicity, we focus on a relatively simple covariance scheme and data observed at equal intervals along a transect; we briefly indicate how generalizations to more complicated covariance functions and higher dimensions will operate.  相似文献   

6.
武强  崔芳鹏  熊晨  黄银洲  孙晨 《地学前缘》2021,28(6):256-262
国土空间类型的综合划分是其后续规划、开发利用与保护的基石。首先,基于现有国土空间的主要类型及其深入划分的现实需求,选取空间维度、空间性质、使用用途、矿产资源价值/矿业空间规模和地下工程/空间规模作为文中对国土空间类型进行进一步划分的主要依据;其次,基于上述主要依据提出了较为完善的国土空间类型划分方案与体系,其涵盖了包括二维平面视角和三维立体视角的29类和45亚类陆域和海域国土空间;最后,简要分析了以上提出的不同类型国土空间的主要特征和规划开发要点,为其实现良性四维规划开发利用与保护提供了重要依据。  相似文献   

7.
The environmental impacts of salmon net-pen aquaculture on the benthic environment were investigated at a commercial fish farm located in coastal Maine waters. This site has a sandy mud bottom and low current velocities, is subjected to episodic sediment resuspension, and way in production for 3 yr prior to this study: We examined both the increase in carbon flux to the benthos caused by the net-pen and the effects of the elevated flux on sediment biogeochemistry and the microbenthic communities. The experimental design involved the establishment of two study sites, an ambient site ca. 100 m from the net-pen and a treatment site around the pen. Sediment traps deployed 1 m above the sediment-water interface indicated that carbon flux to the benthos was increased 1-fold to 6-fold (to a maximum of 5 g m?2d?1) at the edge of the net-pen with little or no increase in carbon flux 10 m from the pen. Unlike carbon flux rates, sediment organic matter inventories showed a complex pattern of change over time. Mineral surface area, organic carbon and nitrogen, digestible protein, and sterol content were initially (April 1991) lower beneath the pen than in ambient sediments. During 1991 ambient sediment accumulated organic matter until July after which it decreased, to a low during November. In contrast, organic matter inventories of sediment beneath the pen remained low until July and then increased to a high during November. These latter gains were associated with the development of bacterial mats at the sediment-water interface. Beneath the pen, microbial and macrofaunal communities were shifted toward those commonly associated with organic enrichment but seasonal trends and storm-related resuspension events also significantly affected these sediment communities. When abundant, most epibenthic organisms were more numerous near the pen than in adjacent ambient areas. These results suggest that net-pen aquaculture can alter the benthic ecosystem in Maine Coastal waters but indicate that the effects are spatially limited.  相似文献   

8.
Molluscs were collected monthly for a year from two low salinity (0–9‰) intertidal marshes dominated by the macrophytesJuncus roemerianus orSpartina cynosuroides in St. Louis Bay, Mississippi. TheJuncus marsh had lower soil organic matter, higher pH and was more frequently inundated than theSpartina marsh. Eight species of gastropods were abundant and dominated in the higherSpartina marsh, while three bivalve species were dominant in theJuncus marsh. Of the common species,Succinea ovalis, Vertigo ovata andDeroceras laeve are gastropods of terrestrial origins;Geukensia demissa granosissima (bivalve) andMelampus bidentatus (gastropod) are euryhaline estuarine species and the remaining gastropods (Detracia floridana, Littoridinops palustris, Onobops jacksoni) and bivalves (Polymesoda caroliniana, Cyrenoida floridana) are brackish species. Most species were capable of continuous recruitment (based on size class analysis), but exhibited peak activity in particular seasons. Bivalve abundance correlated to temperature, and gastropod abundance was negatively correlated to soil pH. These correlations reflect the influence of flooding regime at the two sites. Biomass was greater in theJuncus marsh because of the increased presence of the large-bodiedPolymesoda. Polymesoda represented >90% and >50% of the total biomass in theJuncus andSpartina (except summer) marshes respectively but always <-5% of the individuals collected. Gastropod biomass was the same in both marshes. Species diversity (H′) was greater inSpartina except for summer months. TheJuncus marsh always exhibited greater species richness. Evenness (J′) determined seasonal changes in diversity (H′). Similarity values (Cz) were always quite low, with highest values in spring In contrast to faunal studies from Gulf and East Coast salt marshes, we found 1) fewer species, 2) communities comprised of unique species combinations, 3) greatest mean densities in summer, and 4) potentially less productivity by the molluscs of our sites. These mollusc communities exhibit structural characteristics that emphasize the unique ecotonal nature of the oligohaline marshes within which they are found.  相似文献   

9.
以贵州省2010年石漠化程度分布与土壤类型分布图为基础,运用地图代数原理,通过计算二者的转移矩阵,从而得出不同石漠化程度下土壤类型的空间分布情况,并探讨研究区石漠化背景下,土壤类型与石漠化的空间分布规律,分析石漠化的发生、分布与土壤类型的相关关系。其结果表明:喀斯特地区石质土的石漠化发生率最高达到46.41%,其次为黄棕壤的43.32%,综合排序为石质土>黄棕壤>山地草甸土>棕壤>红壤>粗骨土>石灰土>黄壤>紫色土>水稻土>潮土;分等级讨论时以中度石漠化为主导,且石质土的中度石漠化发生率最高,达到了21.68%。石漠化程度的空间分布在不同土壤类型中存在着明显差异,并且二者之间有一定联系,土壤本身的性质差异是重要的因素之一。   相似文献   

10.
为满足国土空间规划的需求,从自然条件、管理制度构建了建设用地、耕地适宜性评价的禁止性指标和限制性指标。评价中,首先定性分析区域内具体指标对农业、建设等不同功能的限制性,对生态极重要或极敏感区、水域等禁止性指标"一票否决",然后设定不同的指标等级分值、权重,进行综合打分,限制性指标以分值(0~100,分数越高,表示限制性越低,适宜性越高)和权重对国土空间开发适宜性进行限制。结合生态重要性和敏感性评价,以GIS技术为基础,比较同一地块生态、农业、建设适宜性等级,按三者中等级最高的确定空间类型,如果适宜性等级相同,则根据地块的具体资源环境属性、土地利用现状确定空间类型,结合生态系统完整性、农业现代化需求等调整优化生态、农业、建设三类空间。以湖南省为例进行了实证研究,划分建设开发空间20.22%,农业开发空间30.3%,生态保护空间49.48%。  相似文献   

11.
何小芊  张艳蓉  刘宇 《中国岩溶》2017,36(2):275-282
旅游网络关注度是旅游者需求状况和行为习惯在网络上的直观表现。基于百度指数,运用变异系数、基尼系数等定量测算方法,以中国最美五大旅游洞穴为例,对中国旅游洞穴网络关注度的时空特征进行了研究。研究结果显示:旅游洞穴在网络上的关注度较高,并呈现上升的态势,月变化曲线呈双“M”形;网络关注度的省际差异明显,关注度较高的区域主要是洞穴所在的省(市)、邻近省(市)以及东部经济发达省份;旅游洞穴网络关注度的高峰、低谷与国内旅游活动的季节性差异具有耦合性,洞穴的吸引力和吸引范围具有明显的区域性。研究结论为洞穴旅游的发展提供了启示:应充分重视互联网在景区营销中的作用,将网络关注度作为景区经营管理的重要工具,加强与周边景区(点)的合作。   相似文献   

12.
姜振海 《地质科学》2021,56(4):1052-1061
分频反演是近年发展起来的一种先进的地震反演技术。大庆黑鱼泡南部探区存在鼻状构造,是油气富集有利部位。本文基于分频智能反演的储层预测研究,根据地震资料频谱确定分频参数:低频在8 Hz左右,主频35 Hz左右,高频60 Hz左右。根据地震频谱计算得到具有一定带宽的低、中、高频属性。运用支持向量机算法对目标曲线进行分频智能学习训练,学习后曲线相关性达到0.90,满足储层预测的要求。最终,本文将重构曲线与三维地震数据的非线性映射关系引入到二维地震进行分频智能反演,得到二维区阻抗体,对砂岩的预测性较好,为后续的地质建模提供了良好的基础输入数据。  相似文献   

13.
冻融期地质灾害的不断发生,愈来愈引起社会关注并被更多的学者所重视,甘肃黑方台地区冬春交接时期滑坡频发,是研究季节性冻融作用的首选之地.为了探索是否存在冻结滞水效应,揭示冻融作用诱发滑坡灾害机理,建立了气温、地温和地下水位动态等协同观测网.监测数据显示:黑方台地区存在季节性冻融现象,可划分为冻结期(秋冬)、完全冻结期(冬)、冻融期(春夏)、融化期(夏秋)的年季循环过程,也存在昼夜气温变化引起的循环冻融过程;斜坡中段冻结引起的地下水位上升了1.0m,证实了冻结滞水效应的存在.地下水模拟结果表明,冻结滞水引起斜坡坡脚水位壅高幅度超过3m,水平影响距离达到30m以上.冻结前坡体稳定系数为1.19;冻结后仅考虑冻结滞水效应引起的地下水位上升,稳定系数减小到1.09;反复冻融后,考虑黄土强度降低因素,坡体稳定系数降至0.97,说明冻结滞水效应和循环冻融的双重作用是滑坡在春季频发的根本原因.  相似文献   

14.
In order to find out the characteristics and influencing factors of shale oil reservoir in the lower third member of Shahejie Formation of Paleogene in Luojia area of Zhanhua sag, the authors studied the lithology, space type, influencing factors and evaluation parameters of shale oil reservoir by comprehensive analysis of cores, thin sections, SEM and so on. The results show that mineral composition and sedimentary structure are two important factors, based on which the shale oil reservoir can be divided into seven types. The reservoir space of different lithological types varies greatly. Laminated argillaceous limestone and limestone reservoirs were mostly developed, and laminated gray mudstone reservoirs were relatively developed, followed by massive mudstone. The massive argillaceous limestone, massive grey mudstone and laminated siltstone reservoirs were less developed. The reservoir space of shale oil reservoir in the study area was mainly influenced by mineral composition, sedimentary structure, organic matter content and occurrence mode as well as diagenesis. On this basis, calcite content, laminar structure, TOC content, Ro and porosity were selected as evaluation parameters and the shale reservoir in Luojia area of Zhanhua sag was classified into three types: high quality reservoir, favorable reservoir and unfavorable reservoir.  相似文献   

15.
为查明沾化凹陷罗家地区古近系沙河街组三段下亚段页岩油的储层特征及其影响要素,通过岩心、薄片、扫描电镜等多种资料综合分析,开展页岩油储层岩性、储层空间类型、影响因素及页岩油储层评价参数的研究。结果表明: 综合矿物成分和沉积构造2个因素,可将研究区页岩油储层岩性划分为7种类型; 不同岩性储集空间发育有较大差异,纹层状泥质灰岩和纹层状灰岩储集空间最为发育,纹层状灰质泥岩储集空间较发育,块状泥岩储集空间发育一般,块状泥质灰岩、块状灰质泥岩及纹层状粉砂岩储集空间发育较差; 研究区页岩油储层储集空间的发育主要受矿物成分、沉积构造、有机质含量和赋存方式以及成岩作用的影响。以此为基础,选取方解石含量、纹层状构造、总有机碳(Total Organic Carbon,TOC)含量、镜质体反射率(Ro)及孔隙度作为页岩油储层评价参数,将沾化凹陷罗家地区页岩油储层分为优质储层、有利储层和不利储层3类。  相似文献   

16.
刘婷  王寒梅  史玉金  王志辉  陈大平 《地质通报》2021,40(10):1609-1616
“十二五”以来,特大型城市空间需求急剧膨胀与空间资源有限的矛盾逐渐凸显,地下空间的开发利用进入快速发展阶段。在此形势下,了解地下空间承载能力对地下空间科学规划和合理利用具有重要意义。从承载本底(反映地下空间资源禀赋与环境容量优劣程度)和承载状态(反映地下空间资源供容能力与经济社会发展的匹配程度)2个角度建立地下空间承载力评价指标体系,进行地下空间承载力评价的研究,为特大型城市地下空间的开发利用提供技术支撑。以上海中心城区为例进行评价,借助三维建模技术,立体展示地下空间资源承载能力。结果表明,上海中心城区地下空间资源承载能力总体较好,可进一步合理开发地下空间,提高空间利用率,缓解空间资源有限的压力。  相似文献   

17.
滑坡易发性评价是精细化滑坡灾害风险评价的基础。为了提升滑坡易发性评价模型的精度和稳健性,以三峡库区万州区燕山乡为例,选取工程地质岩组、堆积层厚度等九个影响因子构建滑坡易发性评价指标体系,应用信息量模型定量分析滑坡发育与指标之间的关系。在此基础上,随机选取70%/30%的滑坡样本作为训练/验证数据集,应用极致梯度提升模型(extreme gradient boosting, XGBoost)开展易发性评价。随后从模型预测精度和模型稳定性两方面将其与决策树模型(decision tree, DT)和梯度提升树模型(gradient boosting decision tree, GBDT)进行对比。结果表明:研究区堆积层滑坡主要受长江水系、堆积层厚度和工程地质岩组影响。XGBoost模型具有最高的准确率(94.3%)和预测精度(97.3%)。在模型稳定性验证中,平均预测精度最高(97.3%),优于DT(91.3%)和GBDT(95.7%),模型标准差和变异系数均为0.01,低于其余两种模型。XGBoost在区域滑坡易发性评价与制图中得到了可靠的结果,为滑坡灾害空间预测提供了新的技术支撑。  相似文献   

18.
遥感技术以其独特的空间和波谱特性,使其在成矿预测中的地位更加稳固。它可以从宏观和多方位的角度预测矿床存在的有利区域;地质异常作为一种新的地质理论,通过定量统计分析方法把各种有利的成矿地质条件进行成矿有利度得分,地质异常场是一个综合异常场,是各种成矿地质因素的综合反映,地质异常综合评价更多是侧重于微观的,局部的分析,基于遥感技术和地质异常理论自身的优势和局限性,笔者把遥感和地质异常相结合,对兰坪盆地的成矿有利区域进行综合评价,并得到了很好效果。  相似文献   

19.
冻结作用下粉土-混凝土接触面抗拉强度试验研究   总被引:1,自引:1,他引:1  
为探究冻结作用下土与结构接触面抗拉强度的影响因素及变化规律, 开展了冻结状态下多种含水率、 温度及干密度的粉土-混凝土接触面抗拉强度正交试验研究。试验结果表明: 在试验温度下,粉土-混凝土接触面的冻结抗拉强度约为饱和黄土的1/10, 粉质黏土的1/10 ~ 1/7; 含水率对接触面的冻结抗拉强度影响最大, 其次是温度、 干密度; 在试验含水率范围内, 接触面的冻结抗拉强度与含水率正相关; 温度降低会增大接触面冻结抗拉强度, 在-2 ℃至-6 ℃, 冻结抗拉强度迅速增长, 在-6 ℃以后, 冻结抗拉强度的增长速率显著减小。结果证明: 低温、 高含水率、 低干密度条件下, 接触面冻结抗拉强度达到最佳; 三种因素对接触面冻结抗拉强度具有不同的影响程度, 其中含水率、 温度影响显著, 干密度影响不显著; 在试验含水率区间内, 接触面冻结抗拉强度随含水率增长呈线性增长态势, 且含水率、 温度之间存在交互作用; 随温度降低, 存在一临界负温, 接触面冻结抗拉强度由迅速增长转为缓慢增长。  相似文献   

20.
杨税务潜山位于廊固凹陷北部,裂缝孔隙型储层发育,地质综合研究表明该区处于油气运聚的有利方向,但由于其储层埋藏深,地震资料成像精度低,常规属性预测有效储层难度大,多解性强.本文在充分分析已钻井地球物理响应特征的基础上,优选了对有效储层响应敏感的3个属性——平均振幅、方差属性、弧长属性,并计算有效储层厚度与优选属性之间的相...  相似文献   

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