成矿区三维可视化与立体定量预测——以钦-杭成矿带庞西垌地区下园垌铅锌矿区为例

矿产资源是人类生存与社会进步的根本物质保障。近年来,随着地表矿、浅部矿产资源的日益枯竭,采用新技术、新方法的深部矿产资源预测成为地质勘查的主要研究方向。基于数字化、三维可视化及矿产定量预测为主的三维地质建模技术,为当前矿产资源远景预测与找矿工作提供了有力的工具。本文在现代成矿预测理论研究基础上,运用三维地质建模技术建立了钦杭成矿带下园垌矿区地质、地球物理、地球化学、钻孔等三维模型,揭示了区内构造地质特征、地球化学异常表征及地层岩体要素,据此探讨了矿床的成因及矿体分布特征。并在此基础上,采用证据权方法对研究区地质、地球物理、地球化学等多源信息进行融合,运用断裂缓冲区、地球化学异常、东岗岭组沉积岩地层等为证据因子来计算单位体积成矿后验概率,进行立体成矿预测,并圈定出铁锰矿、方铅闪锌矿、铅锌银综合矿等3处找矿有利靶区及估算出预测区内矿产资源储量总量为88710吨。研究结果表明:综合分析地质、地球物理、地球化学及钻孔数据进行矿区的三维地质空间定位、定量预测研究,可以有效的识别矿致异常信息,圈定找矿远景区,为成矿预测研究领域提供了新方向,可以将此方法应用至其他矿山。     

河南栾川西沟铅锌银金矿床三维地质建模与深部找矿预测评价

随着矿区浅部矿的日益减少,深部找矿越来越受到重视,三维地质建模技术在成矿预测、资源定量评价等方面得到了广泛的应用。本文利用三维地质建模平台GOCAD中的三维建模技术及地质统计学等方法,基于收集测试得到的地质图、钻孔和采样点的地层、岩性、构造、品位等数据,构建了西沟铅锌银金矿区的三维地质模型,包括断裂构造模型、矿体模型及地层模型等,并且通过离散光滑插值及克里金插值等方法建立了西沟铅锌银金矿区的三维属性模型,完成了矿区3处找矿预测靶区的圈定与评价。基于地质认识及建立的矿区三维地质模型的研究认为:(1)该矿床的找矿有利标志主要为地层、构造、辉长岩以及品位指示等4个方面;(2)基于三维地质建模技术的找矿预测方法科学有效;(3)S139矿体的中部及东南部深部仍有找矿潜力。本文能够为将来的深部找矿突破提供一定的参考依据。     

基于三维地质建模及可视化的大比例尺深部找矿预测研究及应用:以内蒙古柳坝沟矿区为例

随着三维地质信息技术的发展完善,三维预测是大比例尺深部找矿预测的重要途径和发展趋势。文中以内蒙古柳坝沟矿区313号脉为例,探讨了基于三维地质建模及可视化进行大比例尺三维深部综合找矿预测的技术流程和方法,通过对矿区地层、构造、岩脉、矿体和蚀变带的三维地质建模及可视化成矿地质条件分析,结合原生晕三维异常分析,建立了矿区钾硅化蚀变岩型金矿的综合找矿模型;通过三维块体建模及三维成矿预测因子的量化运算,采用要素叠加法完成了矿区3个预测靶区的圈定与评价。结果表明：柳坝沟313号脉中东部深部仍有较大的找矿潜力;基于三维地质建模及可视化的大比例尺找矿预测方法科学有效。     

基于CART算法的三维成矿预测研究——以安徽白象山矿区为例

把地质大数据和人工智能技术引入矿产资源定量评价及成矿预测体系中,提高了海量地质数据的有效信息挖掘,弥补了传统方法的不足。本文基于白象山矿区基础地质资料和物化探成果资料,利用三维地质体建模技术和三维空间分析技术,量化三维控矿因素,建立了一种基于CART 算法的三维成矿预测模型。通过在白象山矿区的实验表明：该模型能较好的定位已知矿体,并且预测出在已知矿体北部、东部、东北部、西部、南部和东南部具有较高的成矿概率,可圈定找矿靶区。该模型将地质大数据应用于找矿勘探工作,具有纯数据驱动、预测精度高、预测结果可靠等优点。研究发现,该模型的预测效果与训练数据集的数量、矿控因素提取、决策树深度等有关。     

三维地质模拟在深部找矿勘探中的应用

我国矿产资源形势严峻,使深部找矿勘探工作的重要性大大提高。三维地质模拟作为一种新型有效技术,利用立体建模的方式建立矿床三维模型,可定量定位地表达各种地质信息,有效地恢复矿区的深部与浅部的构造形态,这些地质信息共同存在于相同的三维空间中,受钻孔等直接信息数据的约束,更接近现实世界。本文论述了三维地质模拟在深部找矿工作中的广泛应用,包括深部矿床等地质体建模、综合分析、多种图件的自动绘制等,可为矿床储量估算、成矿规律总结、深部成矿预测和矿山生产等工作提供直观、快速的数据和技术支持。     

宁芜盆地白象山矿区人工神经网络 三维成矿定位预测研究

本文基于三维地质环境,综合白象山矿区积累的地质资料和物探成果,首先开展三维地质建模工作,详细刻画了白象山矿区的三维地质结构;在三维地质模型基础上,利用三维空间分析手段对三维控矿因素进行定量挖掘,提取了多种三维控矿因素;最后采用人工神经网络方法进行三维成矿定位预测。预测结果显示,人工神经网络三维成矿定位预测能很好的定位出已知矿体,同时显示,在已知矿体北部及东部的深边部具有较高的成矿概率,可作为开展进一步找矿勘探的靶区。因此,人工神经网络三维成矿定位预测对于白象山矿区的应用是有效的,可服务于新老矿区的深边部三维成矿定位预测,同时可为隐伏矿、盲矿的成矿预测和优选靶区提供定量、定位新的方法和途径。     

三维地质建模在矿床成矿规律研究和找矿靶区预测中的应用——以萨尔朔克矿区为例

通过三维地质建模开展了萨尔朔克矿区成矿规律研究,实现深部找矿靶区定位预测,并依托矿山勘查进行验证.研究采用Geomodeller三维建模软件创建矿区三维地质模型,在建模过程中逐步发现了前期对矿区地质认识中存在的诸多问题和错误,有利地促进了矿区成矿规律的研究.通过建模发现矿区存在上、下两个储矿空间(矿囊),宏观上呈串珠状...     

固体勘查开发信息系统与三维地质建模在福泉大湾超大型磷矿勘查中的应用

随着矿区浅部矿的日益减少,深部找矿越来越受到重视,三维地质建模技术在成矿预测、资源定量评价等方面得到了广泛的应用.本文以黔中磷矿矿集区超大型矿床"大湾磷矿"为例,利用QuantyPES三维建模软件基于地质大数据的特征和结构分析的基础上,通过对地质图、钻孔和采样点的地层、岩性、构造、品位等数据的收集、分析和提取,构建了福...     

胶西北夏甸金矿控矿地质因素分析与深部找矿预测

夏甸金矿床位于胶西北金矿矿集区,成矿作用受区内招平断裂带控制。随着夏甸金矿床找矿工作向深部发展以及地质勘查资料的充分积累,定量化的成矿预测研究成为夏甸矿区深部找矿工作的重要突破点。文章采用面向深部找矿的隐伏矿体立体定量预测原理,基于多源勘查数据构建三维地质模型进行控矿地质因素的三维定量分析,获取反映成矿规律的成矿信息,以多元回归分析方法建立三维预测模型,并应用于夏甸金矿深部找矿。最终得出的相关三维模型和控矿地质因素能为成矿作用研究提供定量的数据支撑,圈定的立体找矿靶区对于夏甸矿区深部找矿具有重要意义。     

基于数字模型的居隆庵铀矿床三维成矿预测

文章基于三维地质建模与地学统计分析相关理论,在江西相山铀矿田主要矿床成矿地质背景、矿床地质特征及成矿规律的研究认识基础上,运用地质建模软件SKUA-GOCAD,建立了居隆庵铀矿床的地形地貌、构造、地层和矿体三维数字模型,并开展了成矿有利信息定量提取分析。运用三维证据权法和三维信息量法对居隆庵铀矿床开展了“定位-定量-定概率”的隐伏矿体三维定量预测研究工作。通过对矿床定量预测获得了成矿高值区,圈定了5个靶区（3个A级靶区和2个B级靶区）,并开展了资源量估算,计算出总资源量为10 983 t。预测结果表明居隆庵矿床找矿潜力巨大,研究成果为该矿区的后续矿产勘查工作提供了重要参考依据,同时也为相山盆地铀矿床的勘探开发提供了技术支持和找矿思路。     

Identifying variably saturated water-flow patterns in a steep hillslope under intermittent heavy rainfall

The objective of this paper is to identify water-flow patterns in part of an active landslide, through the use of numerical simulations and data obtained during a field study. The approaches adopted include measuring rainfall events and pore-pressure responses in both saturated and unsaturated soils at the site. To account for soil variability, the Richards equation is solved within deterministic and stochastic frameworks. The deterministic simulations considered average water-retention data, adjusted retention data to account for stones or cobbles, retention functions for a heterogeneous pore structure, and continuous retention functions for preferential flow. The stochastic simulations applied the Monte Carlo approach which considers statistical distribution and autocorrelation of the saturated conductivity and its cross correlation with the retention function. Although none of the models is capable of accurately predicting field measurements, appreciable improvement in accuracy was attained using stochastic, preferential flow, and heterogeneous pore-structure models. For the current study, continuum-flow models provide reasonable accuracy for practical purposes, although they are expected to be less accurate than multi-domain preferential flow models. Electronic Publication     

水-岩相互作用模拟的研究进展

水 岩相互作用的地球化学模拟已在模型建立和软件的开发方面取得了较大的进展。地球化学模型发展经历了从反向模拟到正向模拟,以及到现在的反应性溶质运移模拟的发展过程。许多计算模拟软件被开发出并投入到实际应用中,现在的模拟技术已能处理较大范围内温度变化、压力变化、组分变化,以及各种地质条件下的水 岩地球化学作用。许多水 岩相互作用问题要回答地质作用的过去历史,要解释或预测未来可能水环境变化,通过模拟已获得满意的解决。目前水 岩作用地球化学模拟取得的重要进步是动力学模型和耦合运移模拟已取得了实质性进展,并应用于实际研究之中。     

Using Sequential Indicator Simulation as a Tool in Reservoir Description: Issues and Uncertainties

Flow simulation studies require an accurate model of the reservoir in terms of its sedimentological architecture. Pixel-based reservoir modeling techniques are often used to model this architecture. There are, however, two problem areas with such techniques. First, several statistical parameters have to be provided whose influence on the resulting model is not readily inferable. Second, conditioning the models to relevant geological data that carry great uncertainty on their own adds to the difficulty of obtaining reliable models and assessing model reliability. The Sequential Indicator Simulation (SIS) method has been used to examine the impact of such uncertainties on the final reservoir model. The effects of varying variogram types, frequencies of lithology occurrence, and the gridblock model orientation with respect to the sedimentological trends are illustrated using different reservoir modeling studies. Results indicate, for example, that the choice of variogram type can have a significant impact on the facies model. Also, reproduction of sedimentological trends and large geometries requires careful parameter selection. By choosing the appropriate modeling strategy, sedimentological principles can be translated into the numerical model. Solutions for dealing with such issues and the geological uncertainties are presented. In conclusion, each reservoir modeling study should begin by developing a thorough quantitative sedimentological understanding of the reservoir under study, followed by detailed sensitivity analyses of relevant statistical and geological parameters.     

Mortar coupling and upscaling of pore-scale models

Pore-scale models are becoming increasingly useful as predictive tools for modeling flow and transport in porous media. These models can accurately represent the 3D pore-structure of real media. Currently first-principles modeling methods are being employed for obtaining qualitative and quantitative behavior. Generally, artificial, simple boundary conditions are imposed on a model that is used as a stand-alone tool for extracting macroscopic parameters. However, realistic boundary conditions, reflecting flow and transport in surrounding media, may be necessary for behavior that occurs over larger length scales or including pore-scale models in a multiscale setting. Here, pore-scale network models are coupled to adjacent media (additional pore-scale or continuum-scale models) using mortars. Mortars are 2D finite-element spaces employed to couple independent subdomains by enforcing continuity of pressure and flux at shared boundary interfaces. While mortars have been used in the past to couple subdomains of different models, physics, and meshes, they are extended here for the first time to pore-scale models. The approach is demonstrated by modeling single-phase flow in coupled pore-scale models, but the methodology can be utilized to model dynamic processes and perform multiscale modeling in 3D continuum simulators for flow and transport.     

环境地球化学模型的应用与发展

环境地球化学模拟是环境科学、地球化学等学科交叉的一个重要领域。这里在总结形态与饱和度模型、表面吸附模型、反应途径模型、逆向模型、复合反应溶质运移模型以及动力学模型原理的基础上,对包含上述模型的各种地球化学模拟软件进行了优缺点比对。总结了各模型在当前环境地化研究领域的重要应用课题,这将为从事相关领域的研究提供一些相对较新、较综合的信息,最后还针对环境地球化学模型的不足进行了相关探讨,对地球化学模型的发展趋势进行了预测。     

Recharge and groundwater models: an overview

Recharge is a fundamental component of groundwater systems, and in groundwater-modeling exercises recharge is either measured and specified or estimated during model calibration. The most appropriate way to represent recharge in a groundwater model depends upon both physical factors and study objectives. Where the water table is close to the land surface, as in humid climates or regions with low topographic relief, a constant-head boundary condition is used. Conversely, where the water table is relatively deep, as in drier climates or regions with high relief, a specified-flux boundary condition is used. In most modeling applications, mixed-type conditions are more effective, or a combination of the different types can be used. The relative distribution of recharge can be estimated from water-level data only, but flux observations must be incorporated in order to estimate rates of recharge. Flux measurements are based on either Darcian velocities (e.g., stream baseflow) or seepage velocities (e.g., groundwater age). In order to estimate the effective porosity independently, both types of flux measurements must be available. Recharge is often estimated more efficiently when automated inverse techniques are used. Other important applications are the delineation of areas contributing recharge to wells and the estimation of paleorecharge rates using carbon-14. Electronic Publication     

物理模拟材料流变性质研究现状

模拟材料的选用以及其相关参数的测定是物理模拟实验的基础.当前采用的延性材料能通常有粘泥、石蜡、松香、塑化松香、塑胶粘土等,国内使用的流变仪主要为毛细管流变仪、旋转流变仪、落球式流变仪,国外对三轴流变仪的研制、应用已见成效.今后应加强新型模拟材料的研制、开发,同时积极研制、引进合适的流变仪.     

Stochastic simulations of fault networks in 3D structural modeling

3D structural modeling is a major instrument in geosciences, e.g. for the assessment of groundwater and energy resources or nuclear waste underground storage. Fault network modeling is a particularly crucial step during this task, for faults compartmentalize rock units and plays a key role in subsurface flow, whether faults are sealing barriers or drains. Whereas most structural uncertainty modeling techniques only allow for geometrical changes and keep the topology fixed, we propose a new method for creating realistic stochastic fault networks with different topologies. The idea is to combine an implicit representation of geological surfaces which provides new perspectives for handling topological changes with a stochastic binary tree to represent the spatial regions. Each node of the tree is a fault, separating the space in two fault blocks. Changes in this binary tree modify the fault relations and therefore the topology of the model.     

Penetration modeling of ultra-high performance concrete using multiscale meshfree methods

Terminal ballistics of concrete is of extreme importance to the military and civil communities. Over the past few decades, ultra-high performance concrete (UHPC) has been developed for various applications in the design of protective structures because UHPC has an enhanced ballistic resistance over conventional strength concrete. Developing predictive numerical models of UHPC subjected to penetration is critical in understanding the material's enhanced performance. This study employs the advanced fundamental concrete (AFC) model, and it will run inside the reproducing kernel particle method (RKPM)-based code known as the nonlinear meshfree analysis program (NMAP). NMAP is advantageous for modeling impact and penetration problems that exhibit extreme deformation and material fragmentation. A comprehensive experimental study was conducted to characterize the UHPC. The investigation consisted of fracture toughness testing, the utilization of nondestructive microcomputed tomography analysis, and lastly projectile penetration shots on the UHPC targets. To improve the accuracy of the model, a new scaled damage evolution law (SDEL) is employed within the microcrack informed damage model. During the homogenized macroscopic calculation, the corresponding microscopic cell needs to be dimensionally equivalent to the mesh dimension when the partial differential equation becomes ill posed and strain softening ensues. To ensure arbitrary mesh geometry for which the homogenized stress-strain curves are derived, a size scaling law is incorporated into the homogenized tensile damage evolution law. This ensures energy-bridging equivalence of the microscopic cell to the homogenized medium irrespective of arbitrary mesh geometry. Results of numerical investigations will be compared with results of penetration experiments.