不同测站点云数据的配准算法     

高益忠 《北京测绘》2020,(2):180-184

随着三维激光扫描技术的发展,利用三维激光扫描仪采集信息,构建三维模型成为了热门的课题。由于受到观测环境、观测方向等影响,无法一次性地获得物体的所有的点云数据。因此,不同视角下点云数据的配准成为了三维建模中的关键技术,直接影响了最终的重合结果以及模型精度。本文着重研究主方向贴合法和最近点迭代算法(ICP算法),基于matlab平台编写算法,并对算法进行研究,得出配准结果以及配准精度。  相似文献   

水平分支注浆孔卡埋钻事故处理实践          下载免费PDF全文

石逊  刘江  李红梅  伍晓龙  王雷浩 《探矿工程》2020,47(9):33-38

近年来煤矿奥灰治水注浆定向钻进技术发展迅速，多分支超深水平注浆孔数量激增。在水平注浆孔施工过程中，普遍存在地层漏失量大，泥浆突然失返，小径钻孔裸孔段长，水平段孔眼轨迹复杂，控制难度大，靶点技术误差要求严，定向仪器、工具等价格昂贵，施工风险相对较高，极易发生埋钻卡钻事故。一旦发生卡钻事故，就会面临着处理周期长、处理难度大等问题，传统的卡埋钻处理方法在水平注浆孔中应用效果不明显。通过采用空压机输送压缩空气，破坏水平孔着床的沉砂结构，将着床的沉砂吹出孔外或吹入地层裂隙，成功地实现了解卡。总结了水平注浆孔施工中卡埋钻事故的预防措施。  相似文献   

SR-28地热井坍塌卡钻事故的处理          下载免费PDF全文

李振杰  徐云鹏  王平  宗振海 《探矿工程》2011,38(9):49-51

就SR-28地热井出现的由坍塌引起的卡钻事故原因进行了分析,针对事故原因分别采用了套铣、测卡、爆炸松扣等技术手段进行了处理,并取得了成功。介绍了该井事故的处理技术措施。  相似文献   

Separation of obliquely incident and reflected irregular waves by the Morlet wavelet transform   总被引：1，自引：0，他引：1  

Yuxiang Ma  Guohai Dong  Xiaozhou Ma 《Coastal Engineering》2011

An existing 2D time-domain method for separating irregular incident and reflected waves by wavelet transform [Ma et al., 2010. A new method for separation of 2D incident and reflected waves by the Morlet wavelet transform. Coastal Eng., 57(6):597–603] is extended to account for obliquely incident irregular waves propagating over sloping bottoms. The linear shoaling and refraction coefficients are adopted to determine the amplitude and phase changes of waves. The optimal central frequency of the Morlet wavelet is determined by the minimum Shannon wavelet entropy. Numerical tests show that the present method can accurately separate waves over horizontal depths. For waves at sloping bottoms, however, the separation errors increase as bottom slope increases and are significant for waves with incident angle larger than π/3.  相似文献   

基于模式识别理论的卡钻类型判别分析          下载免费PDF全文

吴军  臧艳彬  陈星星 《探矿工程》2015,42(10):31-34

将模式识别理论中的支持向量机、Bayes判别分析以及多元回归分析应用于卡钻类型判别分析,建立了基于模式识别理论的卡钻判别模型。以近几年川东北卡钻数据为例进行了算例分析,结果表明：采用支持向量机、Bayes判别法及多元回归法对卡钻类型判别的结果与实际结果的误判率分别为1.92%,11.52%,61.54%。支持向量机（SVM）判别结果精度最高,但其判别方程式较为复杂,不能直观看出各分量对结果的影响程度;多元回归分析判别方程形式简单,可以直观表达各参量与卡钻之间的密切程度,但其判别精度较低;Bayes判别法计算精度介于二者之间,但其判别精度与判别式的个数密切相关。  相似文献   

Tests and applications of an approach to absorbing reflected waves towards incident boundary     

张洪生  王炎  许春辉  商辉  于小伟 《中国海洋工程》2013,27(6):703-718

If the upstream boundary conditions are prescribed based on the incident wave only, the time-dependent numerical models cannot effectively simulate the wave field when the physical or spurious reflected waves become significant. This paper describes carefully an approach to specifying the incident wave boundary conditions combined with a set sponge layer to absorb the reflected waves towards the incident boundary. Incorporated into a time-dependent numerical model, whose governing equations are the Boussinesq-type ones, the effectiveness of the approach is studied in detail. The general boundary conditions, describing the down-wave boundary conditions are also generalized to the case of random waves. The numerical model is in detail examined. The test cases include both the normal one-dimensional incident regular or random waves and the two-dimensional oblique incident regular waves. The calculated results show that the present approach is effective on damping the reflected waves towards the incident wave boundary.  相似文献   

Discussion of “Wave setup and setdown generated by obliquely incident waves” by T.-W. Hsu et al., Coastal Engineering, 53, 865–877, 2006     

Fengyan Shi  James T. Kirby 《Coastal Engineering》2008,55(12):1247-1249

In the recent paper by Tai-Wen Hsu, John R.-C. Hsu, Wen-Kai Weng, Swun-Kwang Wang, and Shan-Hwei Ou (Coastal Engineering, 53, 865–877, 2006), the authors derived theoretical formulations for calculating the wave setup and setdown induced by obliquely incident waves on a beach. The derivation of an expression for setdown contains errors which would lead to an imbalance in longshore momentum flux outside the surfzone. We correct their derivation and give results in terms of the radiation stress concept in a general case including an oblique wave incidence. We also point out that the correct form of wave setdown is important to describe the zero-net force in the momentum balance outside the surfzone.  相似文献   

空气反循环连续取样施工中卡钻事故的预防与处理          下载免费PDF全文

李雪峰  白玉鹏 《探矿工程》2014,41(8):40-45

利用空气反循环连续取样钻进技术,在露天矿山进行生产勘探施工,对所遇到的卡钻问题进行原因分析,确定了相应的操作规程,以便预防卡钻事故的发生,并通过施工辅助孔和套铣技术,在处理卡钻事故方面取得了很好的效果。  相似文献   

用反射波法振幅比判定单桩相对承载力的尝试     

郭铁栓  李祺 《岩土力学》1998,(3)

利用动测桩中的桩底反射信号研究了应力波在桩体和土体中的衰减情况。结果表明,应力波在桩体中的衰减比在土中小的多,在考虑了桩周土与反射系数的关系后,尝试给出应用桩底反射信号与桩头人射信号振幅之比判定单桩承载力相对大小的基本理论和初步研究结果。  相似文献   

预防油页岩地层钻进中压差卡钻的措施     

赵宪富  台沐礼  孙德学  张元清  吕洪富 《探矿工程》2008,35(9):21-23

分析了油页岩地层钻进中压差卡钻发生的原因,提出了预防压差卡钻的途径及处理方法,并通过工程实例来强调预防为主的重要性。  相似文献