为了研究含水松散层固结对地表沉陷的影响,基于固结沉降量对预计参数确定的重要性,分析了影响含水层固结的因素,包括渗透系数、松散层厚度、采动程度和采煤方法.在分析现场实测资料的基础上,采用FLAC3D流-固耦合计算的方法,对覆岩内部位移场和渗流场进行了分析,研究了含水层固结压缩对地表沉降的影响.结果表明不考虑冲积层含水时,地面最大沉陷值为1220mm,考虑冲积层含水时,最大沉陷值为1306mm,下沉量增加86mm.地面沉陷盆地的外缘,沉陷量显著增加,增加量为160mm,最大沉降增加量为7%;走向方向和倾向方向松散层含水条件下均比不含水条件下水平移动量大,走向方向最大相差122 mm,倾向最大相差105 mm.
为了最大限度提升并量化测试无人机激光雷达系统对地表形变量的识别能力,通过系统探讨机载LiDAR技术的误差来源及其有效改进措施,借助5个红外测距仪器检测墩与5、10、30、50、70 mm 5个不同厚度板,使用相同无人机与激光扫描设备对观测墩在放置厚度板前、后重复扫描,将多期数据间作一阶差分处理,最大限度抵消机载LiDAR技术对地面高程扫描的系统误差,以测试目前市场主流机载LiDAR设备对小量形变的监测能力,获得了较为可靠的测试效果。结果表明:在多次重复形变监测中,无人机LiDAR点云扫描技术对地表z方向上形变量的最高识别能力约30 mm。基于该测试结果,无人机激光雷达扫描技术不仅可用于传统地形测绘,还能够用于山体滑坡、矿区地表形变监测、地质运动以及自然灾害跟踪等领域,为同等及以上地表垂直方向形变量级的监测方案与实施提供了参考。
In order to research the possibility of digital close-range photogrammetric surveying in small scale physical simulation experiment, physical model coinciding with engineering practice was constructed based on similar theory. The datum processing method and surveying precision of digital close-range photogrammetric were analyzed. And the function relationship between overburden subsidence factor qr and the ratio z/H of stratum horizon z and mining depth H was researched. The results show that surveying points position mean error along horizontal direction is ±0.131 mm and vertical direction is ±0.192 mm. Therefore, multi-taking station cross direction digital close-range photogrammetric can completely satisfy the precision need of physical simulation experiment. And the empirical formula can be utilized to represent evolution law of stratum subsidence factor.
LI Chun-yi1, CUI Xi-min2, YU Yi-ju3 1. School of Surveying and Landing Information Engineering, Henan Polytechnic University, Jiaozuo 454003, China
