地下空区激光三维探测及稳定性分析

为了解决地下空区对露天矿安全生产的影响,针对洛钼集团露天开采境界下覆不明空区,利用激光三维扫描系统通过地表钻孔对空区进行精确三维探测,把激光三维探测的数据导入SURPAC建立空区三维块体模型,研究了SURPAC和FLAC~(3D)的数据转换方式,并编制相应程序把空区三维块体模型导入软件FLAC~(3D)进行稳定性数值分析.计算结果显示:该空区模型内各单元内的不平衡力趋近于0;节点(6066,4775,1430)处的Z方向位移趋近于恒定值;初始平衡状态下围岩最大位移量约为0.086 m;围岩中最大拉应力为1.52 MPa,应力集中区最大压应力为12.37 MPa,均小于岩体的抗拉、抗压强度.由此表明,该空区上方地表运动停止,空区上方围岩不会发生拉裂破坏,空区目前处于稳定状态.     

A review of laser scanning for geological and geotechnical applications in underground mining

Laser scanning can provide timely assessments of mine sites despite adverse challenges in the operational environment. Although there are several published articles on laser scanning, there is a need to review them in the context of underground mining applications. To this end, a holistic review of laser scanning is presented including progress in 3D scanning systems, data capture/processing techniques and primary applications in underground mines. Laser scanning technology has advanced significantly in terms of mobility and mapping, but there are constraints in coherent and consistent data collection at certain mines due to feature deficiency, dynamics, and environmental influences such as dust and water. Studies suggest that laser scanning has matured over the years for change detection, clearance measurements and structure mapping applications. However, there is scope for improvements in lithology identification, surface parameter measurements, logistic tracking and autonomous navigation. Laser scanning has the potential to provide real-time solutions but the lack of infrastructure in underground mines for data transfer, geodetic networking and processing capacity remain limiting factors. Nevertheless, laser scanners are becoming an integral part of mine automation thanks to their affordability, accuracy and mobility, which should support their widespread usage in years to come.     

地下洞室围岩的卸荷研究

介绍了地下洞室围岩稳定性分析的传统理论及卸荷分析方法。由于不同于加载条件，岩体在卸荷条件下的应力路径不同，分析方法也应不同。在此基础上，论述了卸荷拱理论。     

基于腔增强吸收光谱技术的气体探测研究

以近红外可调谐半导体激光器为光源,以反射率为99.7%左右的平凹镜组成的稳定光学谐振腔作吸收池,构建起一套腔增强吸收光谱（CEAS）系统;以二氧化碳气体（CO2）、一氧化碳气体（CO）、甲烷气体（CH4）以及一氧化碳和二氧化碳的混合气体为样品,利用分子在近红外波段的特征吸收,研究了在近红外波段用CEAS技术探测CO、CO2、CH4等气体的可行性;同时也对基于可调谐半导体激光器的CEAS系统中激光器的波长定标、谐振腔（吸收池）的透射特征等做了研究,获得了CO、CO2、CH4以及CO和CO2混合气体的特征吸收谱,最后对CEAS技术在定量测量方面的能力做了研究.研究结果表明,CEAS技术的探测灵敏度可达5.687×10^-7cm^-1,是一种装置简单、操作方便、灵敏度高、稳定性好的定量吸收光谱技术.     

Numerical Simulation for Two-Phase Water Hammer Flows in Pipe by Quasi-Two-Dimensional Model

The features of a quasi-two-dimensional (quasi-2D) model for simulating two-phase water hammer flows with vaporous cavity in a pipe are investigated. The quasi-2D model with discrete vaporous cavity in the pipe is proposed in this paper. This model uses the quasi-2D model for pure liquid zone and one-dimensional (1D) discrete vapor cavity model for vaporous cavity zone. The quasi-2D model solves two-dimensional equations for both axial and radial velocities and 1D equations for both pressure head and discharge by the method of characteristics. The 1D discrete vapor cavity model is used to simulate the vaporous cavity occurred when the pressure in the local pipe is lower than the vapor pressure of the liquid. The proposed model is used to simulate two-phase water flows caused by the rapid downstream valve closure in a reservoir-pipe-valve system. The results obtained by the proposed model are compared with those by the corresponding 1D model and the experimental ones provided by the literature, respectively. The comparison shows that the maximum pressure heads simulated by the proposed model are more accurate than those by the corresponding 1D model.     

1.3μm GaAsSb/GaAs单量子阱垂直腔面发射激光器的仿真研究

设计了用于提高1.3μm GaAsSb/GaAs单量子阱激光器光反馈的分布布拉格反射镜。基于PICS3D软件建立了单量子阱垂直腔面发射激光器仿真模型,并对有源区量子阱的材料组分和阱宽进行了优化分析。结果表明,量子阱组分为GaAs0.64Sb0.36/GaAs、阱宽为7nm时,器件的阈值电流为0.8m A,斜率效率为0.017W/A。当输入电流为8m A时,输出功率达到0.12m W。     

Numerical investigation of cavity flow at subsonic and transonic speeds

Based on finite volume method,subsonic and transonic flow in 3-D cavity of different lengthto-depth ratios are numerically investigated by using Navier-Stokes equations with k-ωSST two-equation turbulence model and coupled implicit algorithm.The cavity streamline patterns and the static pressure coefficient distributions on the cavity floor are shown,and the flow characteristics of the cavity and the floor pressure coefficient distributions are analyzed.Numerical results demonstrate that the flow characteristics of the cavity at subsonic and transonic speeds are different from that of supersonic ones;length-to-depth ratio is the main factor that affects the flow characteristics of the cavity at subsonic and transonic speeds and causes changes of the cavity flow type;Mach number has a neglectable effect on the cavity flow fields at subsonic and transonic speeds and the cavity floor pressure distributions.     

牙齿窝洞预备标准化数字教学评估研究

牙齿窝洞预备技术的训练是牙科临床教学中的一个重要环节.本文介绍了牙齿窝洞预备标准化数字教学评估的关键技术.通过对学生预备牙体进行非接触式三维扫描,获取牙体颌面的点云数据,以此实现了基于点云的牙体颌面窝洞形态的重建.通过比较标准形态与测试形态在窝洞轮廓线和窝洞深度上的不同,实现了牙齿窝洞预备结果的数字化评估.在此基础上研发了系统原型,该系统的快速评估过程大幅提高了教师的工作效率,同时提高了学生的口腔实践技能技术.     

基于光子晶体的偏振正交双色激光器谐振腔(英文)

利用4×4传输矩阵法,研究具有各向异性缺陷层的一维光子晶体的传输特性,指出利用该结构产生偏振正交双色缺陷模的原理,创建对偏振正交双色模间隔进行调控的方法.基于对各向异性缺陷层掺杂增益物质,研究了获得等增益偏振正交双色缺陷模的方法和条件,为两正交缺陷模在光子晶体激光器中避免模式竞争,获得双模同时谐振提供了理论指导.设计出工作在通信波长1.55μm附近的微尺寸、可调谐超大频差(0～199.8 GHz)的偏振正交双色光子晶体激光器谐振腔.     

全息扫描光盘设计研究

本文介绍的激光多方位条码扫描器采用了全息光盘作为平面光学元件来实现激光束的扫描偏转和聚焦,设计了多面反向镜光学系统以形成多方位的空间扫描网,为实现弱光信号探测和对条码的高速实时识别,还专门设计了模拟信号处理及数字译码电路,给出了全息光盘的有关设计参数及实验结果。     

一种基于CMS数据获取方式的采空区建模方法

采空区是一个非线性复杂系统,研究其三维建模具有较大的难度,且精度难以保证。CMS在地下矿山的应用,较好地实现了采空区数据的精确采集,为三维建模创造了条件。基于CMS获取的数据特点,借鉴现有三维空间模型的构模方法和优缺点,提出了一种新的采空区建模方法:线框-广义四面体(Wire Frame-GTEN)混合模型,并对该模型的建模原理、建模过程、特点等进行了分析研究。     

Cavity 3D modeling and correlative techniques based on cavity monitoring

According to the mining method for Dongguashan Copper Mine and Tongkeng Mine in China, and with the help of the cavity monitoring system（CMS） and mining software Surpac, the 3D cavity models were established exactly. A series of correlative techniques for calculating stope over-excavation and under-excavation, stope dilution and ore loss rates, and the blasting design of the pillar with complicated irregular boundaries were developed. These techniques were applied in Dongguashan Copper Mine and Tongkeng Mine successfully. Using these techniques, the dilution rates of stopes 52-2^#, 52-6^#, 52-8^#and 52-10^# of Dongguashan Copper Mine are calculated to be 2.12%, 8.46%, 12-67% and 10.68%, respectively, and the ore loss rates of stopes 52-6^# and 5-8^# are 4.41% and 3.70%, severally. Furthermore, according to the design accomplished by the technique for a pillar of Tongkeng Mine with irregular boundary, the volume, total length of boreholes and the dynamite quantity of the pillar are computed to be 1.2 ×10^4 m^3, 2.98 km and 10.97 t, correspondingly.     

偏振态稳定型掺铒光纤激光器

提出了一种新型结构的Sigma谐振腔光纤激光器,以价格较为经济的非保偏掺铒光纤作为增益介质。利用Jones矩阵法对该光纤激光器的偏振特性进行了分析。数值仿真计算结果表明其输出偏振态较之相同条件下常规环形腔结构光纤激光器的输出偏振态更加稳定,可应用于光网络测量系统和光纤传感等领域。     

饱和砂土中球形洞室的瞬态动力响应

本文视饮和砂土为流固两相介质,采用工程上通用的土力学模模型,利用Ｌａｐｌａｃｅ变换求解了饱和砂土中球形洞室瞬态响应问题。     

洞室工程地震CT与VSP 联合检测方法及应用实例

地震层析成像(CT)和垂直地震剖面(VSP)法一直作为两种完全分离的探测技术在勘探活动 中运用,而洞室工程地震CT与VSP联合检测方法则是充分利用VSP和CT数据采集方式的兼容性, 通过一体化观测系统参数设计和优化数据处理流程,将两种地震勘探手段融为一体而成为优化组合技 术下的高分辨工程物探方法。方法实验结果表明,地震CT与VSP联合检测方法在近地表岩土工程勘 查应用中几乎可以不增加野外工作费用,就能够同时获取地下洞室工程体施测区间内的地震CT数据 和关于洞室轴向剖面方向的逆向VSP数据体。     

高密度电法在地下空洞探测中的应用研究

在山东省济南市区旧房改造建设工程中,利用高密度电法在盛福片区F地块19栋楼的地基上进行地下空洞探测,分析地下空洞电性异常的几种特征,查清每个地基上空洞的空间位置并进行现场验证,取得了良好的地质效果。通过对地下空洞的逐一处理,一是及时排除了给施工单位人员、设备带来的安全隐患,二是为建设单位的设计与政府决策提供了依据。实践证明高密度电法在探测地下空洞等地质灾害调查及工程勘察领域是首选的先进方法之一。     

光纤激光外腔频谱组束的实验研究

实验中采用激光二极管作为泵浦源、大模面积Er3+Yb3+共掺双包层光纤作为增益介质,利用傅里叶变换透镜、闪耀光栅和输出耦合镜组成的外腔结构,实现了两路Er3+Yb3+共掺双包层光纤激光器的频谱组束。在单路光纤激光器的最大输出功率为520 mW和545 mW、光栅衍射效率为80%的条件下,获得了690 mW的组束功率,组束效率为65%,同时对组束激光的光束质量进行了评估。测得水平和垂直方向的光束质量因子分别为M2x=1.592,M2y=1.335。     

偏振态稳定型掺铒光纤激光器

提出了一种新型结构的Sigma谐振腔光纤激光器,以价格较为经济的非保偏掺铒光纤作为增益介质。利用Jones矩阵法对该光纤激光器的偏振特性进行了分析。数值仿真计算结果表明其输出偏振态较之相同条件下常规环形腔结构光纤激光器的输出偏振态更加稳定,可应用于光网络测量系统和光纤传感等领域。     

基于移动激光扫描系统Trimble MX8的杆状地物提取研究

介绍车载移动三维激光扫描测量系统的发展和特点,以及Trimble MX8系统的构成和功能应用,重点阐述当前国内学者从激光点云数据中提取杆状地物的方法.通过选择两条不同的道路,在不同道路环境下应用不同的参数对杆状地物进行提取,显示不同的提取结果.通过对实验结果进行对比分析得出：面对不同的道路环境,采用相适宜的参数,再加以人工细致的检查,从激光点云数据中提取杆状地物的结果还是可以满足需要的.     

Laser Methane Sensor and the Study of Cross Interference

A methane sensor system was designed based on tunable diode laser absorption spectroscopy (TDLAS) technology and the feature of vertical cavity surface emitting laser (VCSEL) with wavelengths up to several nanometers. We studied the gas present in the methane sensor''s common operation environment. Through absorption spectrum stimulation and experiments,we analyzed the cross interference of the gas of H₂O, CO and CO₂ to methane detection. The results prove that this laser methane sensor has the characteristics of high stability and anti-cross interference.