Effects of caving–mining ratio on the coal and waste rocks gangue flows and the amount of cyclically caved coal in fully mechanized mining of super-thick coal seams

Aimed at determining the appropriate caving–mining ratio for fully mechanized mining of 20 m thick coal seam, this research investigated the effects of caving–mining ratio on the flow fields of coal and waste rocks, amount of cyclically caved coal and top coal loss by means of numerical modeling. The research was based on the geological conditions of panel 8102 in Tashan coal mine. The results indicated the loose coal and waste rocks formed an elliptical zone around the drawpoint. The ellipse enlarged with decreasing caving–mining ratio. And its long axis inclined to the gob gradually became vertical and facilitating the caving and recovery of top coal. The top coal loss showed a cyclical variation; and the loss cycle was shortened with the decreasing in caving–mining ratio. Moreover, the mean squared error(MSE) of the amount of cyclically caved coal went up with increasing caving–mining ratio, indicating a growing imbalance of amount of cyclically caved coal, which could impede the coordinated mining and caving operations. Finally it was found that a caving–mining ratio of 1:2.51 should be reasonable for the conditions.

Stability analysis of longwall top-coal caving face in extra-thick coal seams based on an innovative numerical hydraulic support model

The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.

LED-CAVE沉浸式虚拟现实技术在建筑EPC项目中的应用

研究一种基于LED-CAVE的沉浸式虚拟现实技术,结合建筑信息模型(BIM)技术,通过建(构)筑物及其环境的三维BIM模型与五面LED-CAVE显示系统进行整合,实现多人沉浸式的场景漫游功能。通过人机交互逻辑的开发与外部系统集成,应用于建筑EPC项目的设计、采购、施工等各个领域,可以实现方案设计的沉浸式体验与交流,真正实现所见即所得,提升方案设计的效率,加快方案设计的决策,为旧街区的改造提升方案设计提供有效的辅助和指导作用。

CAVE空间中裸眼VR观影技术研究与系统实现

VR电影通常需借助设备呈现于观众的视野中。本文对VR技术当前发展情况及技术局限性进行了研究,并对洞穴式自动虚拟环境(CAVE)空间的原理、优势和应用现状进行了研究,提出并实现了基于CAVE空间的裸眼VR观影体验方案,并可在后期制作中自定义与现实空间同步的最佳观赏点。在电影科技创新需求和观众审美需求日益增长的当下,CAVE空间中的裸眼VR观影具有广阔的应用前景。

Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical simulations.Moreover,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium theory.The results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition characteristics.Generally,failure first occurs in certain superimposed strata slightly far from the goaf.Subsequently,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the goaf.This process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the goaf.The deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping discontinuities.The effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than expected.The strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling failure.However,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever beams.By taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the key stratum,moving downward toward and upwards away from the goaf.

沉浸式技术CAVE在宋韵文化及历史复现上的应用

在有关政策引导下,以CAVE(洞穴状自动虚拟环境)为代表的各类沉浸式技术逐渐进入公共文化教育空间,改进原有单一、单向的展陈模式,辅助传统文化和历史复现。以宋韵文化为例,CAVE系统的应用影响了人们对历史及当下的空间感知和文化认同。人们通过集体观看,在熟悉的现代性“酷”的技术视觉与文化中,认识到个体在历史中的血脉延续性,从而获得沉浸式的文化认同,维续了中华民族这一身份的连贯一致。进而,这一共享的文化认同通过创意产业带动经济发展,将文化价值转化为经济价值。

Urban Spatial Form Optimization Strategies Based on the Principle of Climate Adaptability of Regional Architecture: A Case Study of Traditional Cave Dwelling Villages in Northern Shaanxi Province

A multitude of climate-adaptive design approaches are embedded in regional architecture,which have a positive impact on addressing the deformed development of urban spatial patterns and the dual challenges of climate and resources.This paper examines the principles of climate adaptability embedded in the site layout and spatial organization characteristics of traditional cave dwelling villages in northern Shaanxi Province.The extracted climate adaptability principles are summarized,and the resulting design strategies that are well-suited to the contemporary urban space form are presented.Through analysis,it can be observed that traditional cave dwelling villages in northern Shaanxi are predominantly situated on south-facing slopes in proximity to water at low altitudes.These villages are characterized by compact building groups and east-west development,which is constrained by the elements of mountains and rivers.A two-level street system is generated,comprising streets parallel to the contour line and roadways perpendicular to the contour line.This results in the formation of a courtyard form enclosed by mountains.Such site layout and spatial organization exhibit excellent climate adaptability with regard to heat,ventilation,and wind storage.In light of the aforementioned considerations,the following urban spatial form design strategies are put forth:①the topographic height difference can be exploited to obtain sufficient sunshine;②the group shape can be optimized in order to reduce building energy consumption;③the best orientation of the building can be chosen to take account of both winter and summer conditions;④the height and length can be combined in order to form natural masking;⑤the D/H ratio of streets and roadways should be controlled to achieve a balance between heat gain and cooling of groups;⑥vents should be set appropriately to optimize group ventilation;⑦climate buffers should be established to increase the level of climate response.

Analysis of the Application of Span-Bridge Technology for Building Highway Tunnels that Go Over Solutional Caves

This article presents a real engineering project showcasing the application of span-bridge construction technology for building a highway that goes over a solutional cave.An overview of the project and the details of applying this technology in highway construction are provided.Besides,strategies for enhancing its construction quality are also proposed.The objective of this analysis is to improve the safety and quality of similar projects.

一种基于CAVE的交互式全景视频显示方法

为了实现全景视频的沉浸式显示,开发了一个基于CAVE的交互式全景视频显示系统.本系统成功地实现了pgr全景视频文件在CAVE上的播放.首先,将全景视频中的每一帧全景图像映射到一个虚拟球面上;其次,使用五个虚拟相机对该球面的四面及顶面进行拍摄,调整各相机的参数使所得各幅图像覆盖整个球面区域,并能够无缝拼接;最后,将所得五幅图像分别投影到CAVE系统中各投影幕中;另外,实现通过鼠标、手柄等输入设备调整CAVE中各投影幕的画面.

PCCAVE:基于连网PC的廉价CAVE系统

讨论了一个基于 PC的廉价 CAVE系统的实现方法 .FCCAVE使用 4台微机配合中低档的图形显示卡构成图形绘制系统 ,代替 SGI工作站和 Reality Engine高档工作站图形卡 .PCCAVE整体上是一个主从式并行计算结构 ,主节点提供人机交互控制接口 ,从节点接受主节点命令和绘制立体图像 .PCCAVE的通信子系统使用 MPI实现 ,实现了并行计算的同步控制和智能信息代理服务 ,图形子系统以 Direct X和 Open GL 作为底层图形 API.还研究了系统的主要瓶颈和性能指标 .利用该系统实现了浙江大学的校园漫游 .结果表明该系统的许多指标都超越或者接近于 SGI Onyx2 ,具有良好的推广前景和较高的实用价值 .

CAVE立体显示系统的搭建及立体图像的几何校正

为了解决由投影机的位置不准确而引起的立体图像视差畸变问题,根据立体图像产生方式以及显示方式的不同,给出了适合于工程上搭建"经济型"CAVE立体显示系统的几种实现方式,包括主动立体方式、主动变被动方式以及直接被动立体方式.将帧缓存中双眼的视景图像分别拷贝到纹理内存中,通过重投影变换计算出B样条曲面控制点坐标并绘制B样条曲面,分别映射纹理内存中双眼图像的纹理到各自的B样条曲面上.通过对左右眼立体图像分别进行几何校正,实现了CAVE多通道立体显示的无缝拼接;通过微调B样条曲面的控制点坐标以及确定曲面阶数,实现了左右立体图像局部位置的调整以及图像平滑度的调整.实验结果显示,该方法不影响视景实时绘制.

基于CAVE的集装箱装卸仿真系统

介绍了基于CAVE系统的集装箱装卸模拟器的硬件平台,给出了本实验室已搭建的CAVE系统的详细配置。阐述了多通道立体显示技术在集装箱装卸模拟器视景系统中的应用,分析了基于被动立体显示的集装箱模拟器的系统构成。通过船舶的压载水调节系统,建立了集装箱装卸操作人员与船舶驾驶员的联系。最后根据拉格朗日运动方程建立了系统的广义坐标下四自由度的运动模型。

Correlation Between the Animal Community Structure and Environmental Factors in Dongbei Cave and Shuijiang Cave of Guizhou Province

Mollusks, arthropods and chordates which were visible to the naked eye were observed and collected in Dongbei and Shuijiang caves of Libo county five times between February and July from 2002 to 2005. Four hundred and forty samples from Dongbei Cave were classified into three phyla, five classes, 10 orders, 20 families and 39 species or groups of species. Four hundred and ninety-eight samples from Shuijiang Cave were classified into three phyla, six classes, 11 orders, 20 families and 25 species or groups of species. Six animal communities were identified in the light belt of the two caves according to their species types and numbers of individuals in the light belt of two cave. The communities which have the highest values of species richness community diversity, maximum diversity, evenness, dominance and community similarity are respectively： B （4. 1059）, H （2.4716）, B （3.3322）, E （0.9042）, C （0.3442） and A - C （0. 5251）. The community diversity and correlation of environmental factors were also studied. The temperature, humidity, content of CO2 and N2, content of organic matter and some inorganic salts in soil were analyzed by Pearson correlation. The results showed that the content of organic matter in soil is positively related to species number, species richness and maximum community diversity, with correlations of 0. 885, 0.909, 0. 868 respectively （two-tailed significance test, P ≤ 0. 05）, and significantly positively related to diversity, with the coefficient of 0.611, （two-tailed significance test, P ≤ 0. 1）. This suggests that the content of organic matter in soil is one of the important elements influencing the community variation of cave animals. Outside the cave, temperature and humidity are important factors impacting on community diver- sity. As the temperature in all seasons in the cave is stable and the humidity is always high （above 90% ）, the temperature and humidity have weak correlation to community diversity in caves.

CAVE系统的发展及在医学领域中的运用

CAVE系统是虚拟现实技术运用中很受欢迎的一个系统工具,越来越多的科研教学工作围绕这一高科技工具展开。结合所访问的卡尔加里大学医学院的CAVE系统分析了该系统的结构和工作原理,并对未来CAVE系统在医学领域的运用作了简要描述。

基于CAVE2的森林虚拟仿真系统应用研究

将CAVE2沉浸式虚拟仿真硬件与森林经营管理需求相结合,设计与实现了基于CAVE2的森林虚拟仿真系统,为开展森林经营管理活动提供了虚拟仿真平台。分析了CAVE2硬件系统性能与特征,提出了研发系统总体结构。分别设计了树木形态结构、森林景观、森林生长与森林经营模拟4个系统模块功能与实现流程,利用Unity三维开发引擎,实现了软件系统的研发。以杉木人工林样地为实验对象,开展了系统应用。结果表明:该方法有效实现了CAVE2虚拟现实硬件系统与Unity可视化模拟软件系统的集成,可在沉浸式三维虚拟仿真环境内开展交互式森林经营与生长预估可视化模拟。该森林虚拟仿真系统具有沉浸感与交互性,可为森林管理提供新的科研与应用平台,可用于指导森林经营实践。

基于网格技术的CAVE定向运动训练系统的设计

定向运动(Orienteering)是指利用地图和指南针到达地图上所指示的各个点标,以最短时间到达所有点标者为胜的一项体育运动。设计基于网格技术的CAVE定向运动训练系统的目的是在室内构建虚拟训练场景,解决必须在山林、郊外训练的限制。介绍了CAVE的结构,设计出训练的硬件环境和软件系统。指出随着信息技术的不断发展,网格技术的应用,虚拟环境的资源共享和协同的实现,CAVE系统将普及和得到广泛应用。

基于CAVE的配电仿真培训系统的实现

针对传统配电仿真培训时场景沉浸感差、操作体验不理想的不足,设计了一种基于CAVE(Cave Automatic Virtual Environment)的配电仿真培训系统。系统采用虚拟建模技术构建仿真的配电三维虚拟场景,并通过高分辨率的三维立体显示方式输出,同时使用虚拟现实互动设备,实现学员与虚拟场景的交互。现场测试结果表明,系统能够使学员产生身临其境的沉浸感受和现场真实操作的体验。

基于Cave系统体感游戏设计的敦煌壁画艺术传播研究--以壁画故事《张骞出使西域》为例

进入近现代社会之后,敦煌壁画赖以生长的时代环境和文化土壤发生了深刻的变化,面对这些变化,我们有必要结合当前的文化生态环境对敦煌壁画艺术进行有效的保护,这不仅是我们当代人的文化使命,也是推动敦煌文化研究向纵深发展的重要途径。基于Cave系统的敦煌壁画主题体感游戏设计,是以技术化的方法实现中国传统文化多样化传播的有益尝试,结合高新的科学技术的发展成果,将敦煌文化根植于大众的日常生活中,以此开辟敦煌壁画艺术保护的新途径,实现对敦煌壁画艺术的活态保护。

史前洞窟阿尔塔米拉(Altamira Cave)壁画微生物群落研究进展

在世界各地广泛分布着人类各个发展时期的历史遗迹,这些遗迹是全人类共同的宝贵财富。然而,这些文化遗产自发现以来,遭受了严重的破坏。造成破坏的因素很多,微生物因素是其中一个重要的方面,对这种损害方式的研究正受到越来越多的关注。本文以西班牙的阿尔塔米拉(Altamira cave)洞窟壁画为例,综述其自发现以来的研究历程和主要成果,为我国的文物保护工作提供参考。

船舶轮机模拟器CAVE系统设计与关键技术研究

设计了一个用于船舶轮机仿真训练的五通道CAVE系统,给出了详细的系统配置。按模块的功能,将软件划分成轮机仿真核心模块、轮机三维仿真模块、轮机二维仿真模块及前台缓存处理模块,并详细介绍了各模块的功能与划分依据。为保证仿真过程中数据与图像的同步,设计并实现了多通道同步机制。给出了虚拟机舱自动漫游算法及交互实体行为模型。该文设计的高度沉浸感船舶轮机模拟器视景系统可有效节约航海教育的实船训练成本。