GNSS连续站阶跃修复及其对数据处理的影响

近年来,由于仪器更换和强震影响,一些长期稳定的GNSS连续站出现了阶跃,严重地影响了参考框架的稳定性和解算精度,理论上这些测站不能再选为参考框架点。针对GNSS连续站阶跃修复及其对数据处理的影响进行了分析,结果表明：1）如果选用未修复阶跃的测站为框架点,将会扭曲解算结果;2）QOCA能够较为便捷地修复测站阶跃;3）修复测站阶跃能够保证参考框架点的稳定性,并能一定程度提高解算精度。     

多扶正器防斜钻具组合在大岗山水电站帷幕灌浆工程中的应用

大岗山水电站帷幕灌浆工区施工局限性显著、地层自然造斜力强,灌浆孔孔斜设计要求高,其顶角要求≤0.5?/100 m,防斜技术难度大。采用多扶正器防斜钻具组合,有效地限制了灌浆孔轴线顶角变化和孔底偏移量,控制了灌浆孔弯曲偏斜,灌浆孔成孔质量明显提高,获得了较好的经济效益。     

Factors influencing the behavior of buried pipelines subjected to earthquake faulting

Seismic ground faulting is a severe hazard for continuous buried pipelines. Over the years, researchers have attempted to understand pipe behavior, most frequently via numerical modeling and simulation. However, there has been little, if any, physical modeling and tests to verify the numerical modeling approaches and assumptions. This paper presents results of five pairs of centrifuge tests designed to investigate the influence of various factors on the behavior of buried high-density polyethylene (HDPE) pipelines subjected to strike-slip faulting. Parameters considered are the soil moisture content, fault offset rate, relative burial depth (H/D), and pipe diameter. The centrifuge test results show that pipe behavior, specifically pipe strain, is nominally not affected by the soil moisture content and fault offset rate when the pipe is subjected to strike-slip faulting. On the other hand, the burial depth ratio (H/D) and pipe diameter influence peak pipe strain, and in some cases, the ground soil failure pattern.     

Errata

正APPLIED GEOPHYSICS,2014,11(2),P.235-244.DOI:10.1007/sl 1770-014-0439-4To Interval Q inversion based on zero-offset VSP data and applications(APPLIED GEOPHYSICS,2014,11(2),237)     

偏心系数和锚腚角对固定锚腚拖曳锚运动的影响

为观测和分析安装中拖曳锚在土中的运动特性,自制了由玻璃水槽、拖曳系统和拉力传感器组成的板锚拖曳试验装置。将硅凝胶与水混合制备成了透明土,依据有效重度强度比确定模型锚材料,按照1:50缩尺比例,在自制板锚拖曳试验装置上开展固定锚腚拖曳锚拖曳试验,研究了偏心系数和锚腚角对固定锚腚拖曳锚运动特性的影响规律。结果表明：该试验装置可以直接观测拖曳板锚嵌入土中运动的全过程;锚眼法向偏心距和切向偏心距不是独立参数,偏心系数能综合描述锚眼偏心对板锚在土中运动的影响;锚腚角是影响板锚在土中运动的重要参数,随着锚腚角增加,板锚最终嵌土深度先增加后减小;随着锚眼偏心系数增加,板锚最终嵌土深度先增加后减小;固定锚腚拖曳锚在土中的运动轨迹近似服从负指数函数曲线。     

UWB TW-TOA测距误差分析与削弱

针对室内环境下UWB TW-TOA测距精度受标准时间偏差和NLOS误差影响明显的问题,采用4阶多项式拟合模型对标准时间偏差进行标定,设计了一种新的基于偏移卡尔曼滤波的NLOS误差鉴别与抑制方法。该方法将测距残差与卡尔曼滤波结合,鉴别出NLOS误差,并将残差值加入到卡尔曼滤波的迭代中,修正卡尔曼滤波的异常值,得到消除NLOS的测量值。利用实测试验对以上算法进行验证,结果表明经过标准时间偏差标定及NLOS误差的鉴别与抑制后,在LOS环境下,UWB TW-TOA测距精度可达到毫米级;在NLOS环境下,测距精度可由原来的0.5m缩小至0.2m,证明了本文方法的正确性和可行性。     

用共偏移距反射法拓展地质剖面的解释深度

针对核电工程选址中的能动断层地质调查工作需要,提出了利用共偏移距浅层地震反射时间剖面来拓展地质剖面解释深度的技术方法,通过物性和岩性的综合解释来提高对能动断层鉴别及其产状确定的可靠性.探测试验结果表明该方法是有效可行的.地质剖面上描述的断裂破碎带在共偏移距时间剖面上反应明显,二者可以相互印证,优势互补.该技术方法可用于类似工程地质调查和第四系覆盖较薄地区的隐伏断层探测.     

late quaternary activity of the qujiang fault and analysis of the slip rate

The Qujiang Fault is one of the most seismically active faults in western Yunnan, China and is considered to be the seismogenic fault of the 1970 M_S7.7 Tonghai earthquake. The Qujiang Fault is located at the southeastern tip of the Sichuan-Yunnan block. In this study, we examine the geometry, kinematics, and geomorphology of this fault through field observations and satellite images. The fault is characterized by dextral strike-slip movements with dip-slip components and can be divided into northwest and southeast segments according to different kinematics. The northwest segment shows right-lateral strike-slip with normal components, whereas it is characterized by dextral movements with the northeast wall thrusting over the opposite in the southeast segment. The offset landforms are well developed along the strike of the fault with displacements ranging from 3.7m to 830m. The Late Quaternary right-lateral slip rate was determined to be 2.3～4.0mm/a through dating and measuring on the offset features. The variation of the slip and uplift rates along the fault strike corresponds well to the fault kinematics segmentation: the slip rate on the northwest segment is above 3mm/a with an uplift rate of 0.6～0.8mm/a; however, influenced by the Xiaojiang Fault, the southeast segment shows apparent thrust components. The slip rate decreases to below 3.0mm/a with an uplift rate of 1.1mm/a, indicating different uplift between the northwest and southeast segments.     

不同太阳、月亮坐标算法对GNSS部分系统误差的影响研究

研究天文年历、JPL星历计算的太阳、月亮坐标的差异及对GNSS导航定位的影响。结果表明,不同星历计算的太阳坐标差异最大为5×10⁸ m,月亮坐标差异最大为3×10⁶ m。天文年历与DE421计算的星固系X方向之间的夹角最大达30′（Y方向与X方向类似）。太阳坐标差异引起的相位绕转改正之间的差异最大达0.3 mm,卫星天线相位中心偏差改正之间的差异最大达3 mm。太阳、月亮坐标差异导致固体潮改正之间的差异最大达3 mm。经实测GPS数据验证,不同星历计算的太阳、月亮坐标差异对PPP的影响可以忽略,建议在PPP中采用计算效率高的天文年历。