地铁盾构隧道洞门钢环圆心坐标的精确测定

给出了测定与计算钢环圆心坐标和半径的方法,按照最小二乘原理进行求解,并根据实际数据进行了验证和分析,实现了地铁盾构隧道洞门钢环圆心坐标的精确测定。     

盾构隧道施工测量中若干问题探讨

盾构隧道施工测量中,对于联系测量的精度要求较高.为消除棱镜纵轴误差在联系测量短边处的影响,本文提出了调换棱镜顺序和棱镜"正倒镜法"两种方法,理论分析比较这两种方法,及其相对于传统测量方法的优越性.采用调换前后视棱镜的方法,偶数站时,可削弱甚至消除棱镜纵轴误差的影响.棱镜"正倒镜法",可完全消除纵轴误差对水平角的影响.对洞门中心测定运用最小二乘法,拟合出洞门所在的空间平面及空间球面,二者交线即为所求空间圆.通过某地铁盾构实际数据,结合盾构机进洞情况,验证了本文提出方法的可行性.     

地铁全线管片姿态复核数据处理方法研究

采用盾构法进行地铁隧道开挖时,盾构区间开挖后主要通过测量得到的管片环中心坐标进行反算获取对应环中心的里程及偏移值。针对于地铁全线多个盾构区间同时施工、复核数据处理量大且数据计算精度要求高的实际情况,本文论述了在地铁全线测量点坐标进行统一反算过程中,如何进行测量点反算时曲线要素的选择及对线元的判断,并结合地铁线路设计特征提出了一种缓和曲线部分任意点坐标反算里程的方法,并验证了该方法的可行性。     

盾构姿态测量原理的比较研究及精度分析

对国内外盾构姿态自动测量系统进行了比较和总结,对盾构姿态的参数和姿态测量的原理进行了梳理,提出了盾构中心坐标偏差和切线偏差的计算方法,并对地铁盾构施工过程中,各个阶段的施工测量精度进行了具体分析和总结。     

地铁隧道中心坐标的计算程序编制浅谈--以南京地铁一号线玄武门至南京站区间为例

本文以南京地铁一号线盾构三标(玄武门至南京站)为例,分析了线路中桩坐标计算程序的编写思路,阐述了根据里程(桩号)求坐标的方法。用计算机对隧道中心与线路中心坐标进行了计算,克服了手工计算缓和曲线及隧道中心与线路中心的偏移量上的繁杂。简化了工作量,保证了测量数据处理的准确与快速。     

地铁盾构施工隧道内平面控制网建立方法

目前长大隧道盾构施工控制测量一般都采用传统支导线法,存在误差累积过快、缺少独立检核点及贯通中误差受施工条件影响较大等问题。本文结合地铁施工建设实例,根据盾构施工现场需求及设计精度要求,探索实施了一种新的盾构施工隧道内平面控制网测量方法,从控制点布设、观测方法及数据处理分析等方面进行详细介绍,并与传统导线测量的两种方法进行精度、可靠性对比分析。试验结果显示,本文方法可以提高盾构隧道平面控制测量精度,强化平面控制点及吊篮点可靠性,有效控制隧道平面累积误差及贯通中误差。     

隧道洞门圈中心测量的几种方法比较

本文就洞门圈中心坐标确定的几种测量方法进行了阐述,并利用这几种方法对青草沙原水工程岛域段隧道某一洞门圈实测数据进行了对比分析,最后得出了这几种方法的优劣及适用性。     

三维激光扫描技术在地铁圆形盾构隧道检测中的应用

从三维激光扫描仪的工作原理出发,阐述了三维激光扫描测量点云数据坐标转换优化设计,并详细介绍了三维激光扫描技术在地铁圆形盾构隧道检测中的点云数据采集流程、处理方法及成果分析,通过与传统方法对比分析验证了三维激光扫描技术在隧道检测中的精度与可靠性,并结合工程实例证明该方法能有效的获取地铁隧道断面测量、椭圆度检测、中心线等成果,为地铁后期的设计、施工、运营维护提供详细的基础资料。     

浅析盾构姿态控制的原理和方法

本文介绍了盾构法隧道施工过程中通过测定固定在盾构上的棱镜坐标推算盾构的位置及姿态参数的原理和方法.     

近景摄影测量支持下的地铁盾构管片姿态测量方法及其应用

传统的地铁盾构管片姿态测量的方法存在作业时间长,与施工流水线交叉作业劳动量大,且无法实时测量等不足。本文提出了利用近景摄影测量的方法对盾构管片姿态进行测量,通过在盾构管片环上铺设人工标志点,使用数码相机进行拍摄,利用光束法平常对摄影图片进行数据解算,得到解算标志点坐标后,再根据空间三点定圆心原理确定盾构环圆心点的坐标。试验结果表明,对比传统测量方法,新方法误差不超过3 cm,能够完全满足盾构管片姿态的测量精度要求,具有很好的推广价值。     

Allowance of lateral breakthrough error for super long tunnels from 20km to 50km

Up to now there is no specification about the allowance of lateral breakthrough error for super long tunnel from 20 km to 50 km. On the basis of the design of GPS networks located outside and inside tunnel traverse network, we propose a method for calculating the influence value caused by control surveying errors.Through a lot of simulative calculations and combination with piercing practice of super tunnels in Wan Jiazai Project, Shanxi province, we present an allowance table of lateral breakthrough error for super long tunnels from 20 km to 50 km.     

Allowance of lateral breakthrough error for super long tunnels from 20km to 50km

Up to now there is no specification about the allowance of lateral breakthrough error for super long tunnel from 20 km to 50 km. On the basis of the design of GPS networks located outside and inside tunnel traverse network, we propose a method for calculating the influence value caused by control surveying errors. Through a lot of simulative calculations and combination with piercing practice of super tunnels in Wan Jiazai Project, Shanxi province, we present an allowance table of lateral breakthrough error for super long tunnels from 20 km to 50 km.     

20～50 km超长隧道(洞)横向贯通误差允许值研究

目前国内超长隧道(洞)工程越来越多,但迄今为止,国内外20～50 km的超长隧道(洞)的横向贯通误差允许值尚无规范可循,在对洞外GPS平面控制网、洞内狭长导线网的布设以及测量误差对横向贯通误差的影响进行深入研究的基础上,提出了影响值的估算方法,通过大量模拟计算,并根据山西省引黄工程超长隧洞的测量和贯通实践,给出了超长隧道(洞)工程横向贯通误差允许值表,可供制定相应的规范和类似的工程实践参考.     

基于惯导和CPⅢ控制点的地铁隧道移动激光扫描三维点云重建

地铁隧道初始运营前,需要对隧道的施工质量和零状态进行检测,传统方法采用全站仪测量隧道的特征点及断面,工作量大、效率低、成果单一。针对上述问题,本文提出了基于惯导和CPⅢ控制点的地铁隧道移动扫描三维点云重建方法,并验证了隧道断面点云、中轴线及轨道中心位置成果精度,满足隧道规划验收测量要求。同时,该方法可同步获得隧道的水平直径、管壁影像、纵断面图及横断面图等成果,既提高了作业效率,其测量成果又可作为轨道交通结构的零状态档案,为地铁隧道规划验收测量及后期运营维护提供翔实的基础资料。     

Characteristics of GPS positioning error with non-uniform pseudorange error

We study the characteristics of the random GPS positioning errors when the pseudorange errors differ for each satellite. A concise, explicit, analytical formula is derived for the covariance of the positioning error by using singular value decomposition. It is composed of a uniform error covariance together with additional contributions from those satellites with larger pseudorange errors. The eigenvectors of the uniform error covariance define the principal directions of the 4-dimensional error ellipsoid, and the eigenvalues are the squares of the semi-axes. The additional part from individual satellites has only one eigenvector and one eigenvalue. This makes the error ellipsoid enlarge mainly along a direction related to both the overall satellite geometry and the position of the specific satellites. The theory is validated by simulating the GPS constellation and pseudorange measurements. The random positioning error is examined while any one or more pseudorange errors are increased. Horizontal positioning error distributions are presented to demonstrate the variations of the orientation and size of the error ellipses with the pseudorange error of a specific satellite. The results show that the analytical formula describes the positioning error accurately.     

高分辨率三维激光扫描数据的微小变形统计分析

地基三维激光扫描数据具有高精度、高空间分辨率的特点,能够改变传统的单点变形观测模式,使传统的点测量向“形测量”转化,因而大量的变形监测数据使得通过数学统计的方法探测变形量小于测量精度的微小变形成为可能。利用高分辨率三维激光扫描数据的微小变形统计分析方法,提出了基于反射值影像和BaySAC的拼接方法提高拼接精度;通过拟合方式提高整体分析精度,而影响拟合精度的主要因素为粗差,因此采用RanSAC算法剔除粗差,提高拟合的精度;然后利用格网化方法消弱偶然误差、修正拼接误差,最终得到变形量。采用建筑墙面及地铁隧道的点云数据进行了微小变形检测的实验,证明了该方法的有效性。     

Improved GRACE science results after adjustment of geometric biases in the Level-1B K-band ranging data

The GRACE (Gravity Recovery and Climate Experiment) satellite mission relies on the inter-satellite K-band microwave ranging (KBR) observations. We investigate systematic errors that are present in the Level-1B KBR data, namely in the geometric correction. This correction converts the original ranging observation (between the two KBR antennas phase centers) into an observation between the two satellites’ centers of mass. It is computed from data on the precise alignment between both satellites, that is, between the lines joining the center of mass and the antenna phase center of either satellite. The Level-1B data used to determine this alignment exhibit constant biases as large as 1–2 mrad in terms of pitch and yaw alignment angles. These biases induce non-constant errors in the Level-1B geometric correction. While the precise origin of the biases remains to be identified, we are able to estimate and reduce them in a re-calibration approach. This significantly improves time-variable gravity field solutions based on the CNES/GRGS processing strategy. Empirical assessments indicate that the systematic KBR data errors have previously induced gravity field errors on the level of 6–11 times the so-called GRACE baseline error level. The zonal coefficients (from degree 14) are particularly affected. The re-calibration reduces their rms errors by about 50%. As examples for geophysical inferences, the improvement enhances agreement between mass variations observed by GRACE and in-situ ocean bottom pressure observations. The improvement also importantly affects estimates of inter-annual mass variations of the Antarctic ice sheet.     

High-frequency signal and noise estimates of CSR GRACE RL04

A sliding window technique is used to create daily-sampled Gravity Recovery and Climate Experiment (GRACE) solutions with the same background processing as the official CSR RL04 monthly series. By estimating over shorter time spans, more frequent solutions are made using uncorrelated data, allowing for higher frequency resolution in addition to daily sampling. Using these data sets, high-frequency GRACE errors are computed using two different techniques: assuming the GRACE high-frequency signal in a quiet area of the ocean is the true error, and computing the variance of differences between multiple high-frequency GRACE series from different centers. While the signal-to-noise ratios prove to be sufficiently high for confidence at annual and lower frequencies, at frequencies above 3 cycles/year the signal-to-noise ratios in the large hydrological basins looked at here are near 1.0. Comparisons with the GLDAS hydrological model and high frequency GRACE series developed at other centers confirm CSR GRACE RL04’s poor ability to accurately and reliably measure hydrological signal above 3–9 cycles/year, due to the low power of the large-scale hydrological signal typical at those frequencies compared to the GRACE errors.     

基于部分最小二乘岭估计的粗差定值定位

在利用部分最小二乘原理进行粗差定值定位时,模型的法方程矩阵可能存在病态性,使得到的粗差定值定位结果不可靠。文中针对观测数据包含多个粗差且法方程病态问题,利用岭估计处理病态问题,建立部分最小二乘岭估计的粗差定值定位方法,给出粗差搜索步骤,利用迭代算法实现多个粗差的定值和定位。通过模拟算例分析部分最小二乘法、部分最小二乘岭估计在粗差搜索方面的效果,从另一个角度探讨粗差处理方法,推广现有的误差理论,证明文中方法的有效性。     

不规则DEM数据的粗差探测算法的应用

粗差作为影响精度的重要因素,其存在会造成DEM空间上的严重扭曲,有时能导致DEM及其产品严重失真,甚至完全不能使用。本文在对现有的粗差探测算法分析的基础上,提出了一种新型的适用于离散形式DEM粗差探测算法,并采用实测的ZX铁路线DEM数据对该算法进行检验,试验结果证实,新算法对不规则DEM粗差的探测有效实用。