成渝城市群城市建设用地扩张格局及规模体系分析     

张亚萍  张平  孙丹峰  刘顺喜  伦飞 《测绘通报》2020,(7):103-107

基于1990—2018年六期城市建设用地监测数据，本文利用城市用地年面积增长率指数、公共边测度、核密度估计、位序-规模法则等方法，刻画成渝城市群扩张演化特征及其发展规律，并对城市群规模体系进行分析。结果表明：成渝城市群城市建设用地扩张呈先快后慢的趋势，空间上呈“中部高速，南北低速”的特点，建设用地扩张密度高值主要集中在成都、重庆二市且城市群内部连片发展不明显。城市群新增城市用地呈现无序蔓延态势，并未趋于紧凑。2000—2010年，成渝城市群规模分布极化，呈现明显的双核首位特征，2010年后规模分布由非均衡趋于均衡。  相似文献   

基于地理国情数据的长江岸线保护和开发利用情况分析     

王丹  柴燕妮  张浩 《北京测绘》2020,(4):507-510

本文基于地理国情数据,从农业垦殖、开发建设、生态修复情况三个方面出发,对长江岸线1 km范围内的保护和开发利用情况进行空间统计分析。通过分析可知:(1)2015~2018年,长江岸线农业垦殖和开发建设力度有所增强;(2)2015~2018年,长江岸线生态修复取得一定的进展,但仍需持续推进。  相似文献   

基于移动三维扫描技术的隧道管片错台分析及应用     

赵亚波  王智 《测绘通报》2020,(8):160-163

错台是地铁隧道的主要病害之一，通常是由于盾构机施工控制不好或是隧道荷载发生变化导致，错台的发生也会引起隧道收敛变形及渗水等其他病害。传统手段主要采用人工巡检等方式进行错台情况的检测，由于受夜间窗口期短的影响，该方法效率低，成果难以精确量化。研究采用基于轨道的隧道移动三维激光扫描系统对隧道错台进行检测，通过快速获取隧道三维点云生成正射影像，并基于正射影像进行管片的划分及里程的匹配，进而根据每一环的三维点云信息计算管片错台情况。以青岛地铁2号线为例，本文介绍了移动扫描技术在地铁隧道管片错台检测的应用情况，为该技术在其他隧道的推广应用提供了一定的借鉴意义。  相似文献   

A new numerical approach to the hyperstatic reaction method for segmental tunnel linings     

Ngoc Anh Do  Daniel Dias  Pierpaolo Oreste  Irini Djeran‐Maigre 《国际地质力学数值与分析法杂志》2014,38(15):1617-1632

This paper proposes a numerical approach to the hyperstatic reaction method (HRM) for the analysis of segmental tunnel linings. The influence of segmental joints has been considered directly using a fixity ratio that is determined on the basis of the rotational stiffness. The parameters necessary for the calculation are presented. A specific implementation has been developed using a FEM framework. This code is able to consider the three‐dimensional (3D) effect of segment joints in successive rings on the tunnel lining behaviour. The present HRM allows one to take an arbitrary distribution of segment joints along the tunnel boundary into consideration. In addition, the rotational stiffness of segment joints has been simulated using nonlinear behaviour, as it is closer to the true behaviour of a joint than linear or bilinear behaviour. The numerical results of three hypotheses on ring interaction, which allow the 3D effect of a segmental tunnel lining to be taken into account, have been compared with data obtained from the shield‐driven tunnel of the Bologna–Florence high‐speed railway line project. The numerical results presented in the paper show that the proposed HRM can be used to effectively estimate the behaviour of a segmental tunnel lining. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

震后建筑进度BIM估计模型改进   总被引：1，自引：0，他引：1       下载免费PDF全文

武炜  崔邯龙  张丽丽 《地震工程学报》2018,40(4):841-847

传统震后建筑进度BIM估计模型,未考虑精益管理对建筑施工的影响,造成建筑成本浪费较多,影响后期建筑施工进度。本文构建基于BIM和精益管理的震后建筑进度评估模型,根据模型细分震后建筑进度评估过程,在此基础上根据BIM实施三维算量,采用进度计划编制子模型获取各分项工程量,确定建筑施工的主要进度计划,实现对建筑进度计划的编制;通过虚拟施工和现实施工两条主线,利用进度控制子模型实现对施工状态的模拟和精益管理。以此为基础,进行挣值分析比较计划施工成本、实际施工成本和挣值曲线,获取震后建筑的施工进度与成本情况。实验结果说明,本文构建的模型可对震后建筑进度和工程成本进行精准估计,能够减少成本浪费。  相似文献   

Stability analysis of tunnels driven in jointed rocks by means of a homogenized limit analysis approach     

Samir Maghous  José E. B. Winiawer  Vanessa F. Pasa Dutra 《国际地质力学数值与分析法杂志》2014,38(18):2009-2032

Conceived as a potential alternative to the classical design methods employed for analyzing the stability of underground structures driven in jointed rocks, the homogenization approach stems from the heuristic idea that, from a macroscopic point of view, a rock mass cut by a network of joints may be perceived as a homogenized continuum. The strength properties of the latter can be theoretically obtained from the failure conditions of its individual constituents: rock matrix and joint interfaces. At the material level, the limit analysis reasoning is used in the context of homogenization to formulate the homogenized strength criterion of a jointed rock mass in the particular situation of a single set of parallel joints. As it could be expected, the obtained closed‐form expressions show the strength anisotropy induced by joint preferential orientation. The support functions (π functions) associated with the homogenized strength criterion are also determined in both plane strain and three‐dimensional cases. This criterion is then applied to the investigation of stability analysis of a tunnel excavated in a jointed rock mass. Upper bounds estimated of the stability factor are derived from the implementation of the kinematic approach directly on the homogenized underground structure. Finally, the approach is applied to analyze and discuss the collapse of the Pinheiros subway station (São Paulo, Brazil). Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

盾构辅助常压开仓技术在南宁地铁隧道中的应用          下载免费PDF全文

曲兆雷 《探矿工程》2020,47(2):88-93

盾构开仓是盾构隧道施工中难以避免的一道工序，结合南宁地铁四号线总部基地站-飞龙路站区间隧道的盾构开仓实践经验，介绍了素桩加降水这一辅助常压开仓技术在南宁地铁隧道中成功应用的实例。在介绍工程应用背景的基础上，详细叙述了辅助开仓方法中素桩及降水施工的技术要点，可为南宁地区盾构开仓方案选择提供指导，也可为类似条件下盾构开仓方案的选择提供借鉴。  相似文献   

2018年9月8日云南墨江M5.9地震震害综述     

周洋  明小娜  卢永坤  闫瀚  杨健强 《华北地震科学》2020,38(1):14-20

2018年9月8日10时31分29秒,云南省墨江县(23.28°N,101.53°E)发生M5.9地震。根据现场调查情况,详细阐述地震灾区房屋建筑结构特点、房屋建筑及生命线工程震害特征,给出房屋建筑震害矩阵,对其震害成因进行分析,并与省内近年相似震级的地震震害进行对比分析,结果表明:本次地震波及范围广、总体震害轻、无人员死亡、地质灾害轻。  相似文献   

高烈度区双洞隧道洞口段地震响应分析与振动台模型试验          下载免费PDF全文

皇民  苑俊杰  赵玉如  毕洁同  王松 《中国地质灾害与防治学报》2020,31(1):113-119

强震作用下,隧道地下结构损伤严重,其中洞口段更是抗震的薄弱环节,但其影响规律和特点目前尚缺乏系统的计算分析和研究。以强震区扯羊隧道为例,首先采用FLAC3D对双洞隧道洞口段地震响应进行分析,再用模型试验的方法进行洞口段模型试验,测量其地震响应应变规律,观测其震害发展情况,并与数值分析结果相互验证。结果表明:地震作用下,隧道仰拱横向位移较大;随着隧道埋深增加,内力逐步增加,其中墙角部位内力较大;洞口处隧道围岩在强震作用下会产生贯通性裂缝,影响隧道洞口稳定;地震作用下的明洞与暗洞交接处内力较大;地震作用下的双洞隧道之间存在较强的动力相互作用。  相似文献   

Analytical solution for longitudinal seismic response of long tunnels subjected to Rayleigh waves     

Yusheng Yang  Haitao Yu  Yong Yuan  Mi Zhao 《国际地质力学数值与分析法杂志》2020,44(10):1371-1385

The longitudinal seismic response of a long tunnel subjected to Rayleigh waves is investigated in this paper. The tunnel is assumed to be infinitely long, has a uniform cross section, and rests on a viscoelastic foundation. The free-field deformation under Rayleigh waves traveling parallel to the tunnel axis is decomposed into two directions, namely, the axial motion and the vertical motion, and transformed into dynamic loads imposed on the tunnel. Based on the Fourier and Laplace integral transform techniques, the governing equations of tunnels are simplified into algebraic equations, and the analytical solutions are obtained with the convolution theorem. The final solutions of the tunnel responses in terms of deflection, velocity, acceleration, axial force, bending moment, and shear force are investigated. The proposed solution is verified by comparison of its results and those from the finite element program ABAQUS. Further parametric analysis is carried out to investigate the influence of soil-structure relative stiffness ratio and wave frequency on dynamic longitudinal responses of the tunnel.  相似文献