矢量波场弹性波Kirchhoff偏移

Based on Kuo and Dai＇s vectorial wave-field extrapolation equations, we derive new Kirchhoff migration equations by introducing unit vectors which represent the ray directions at the imaging points of the reflected P- and PS converted-waves. Furthermore, using the slope of the events on shot records and a ray racing procedure, mirror-image reflection points are found and the reflection data are smeared along the Fresnel zone. The migration method proposed in this paper solves two troublesome imaging problems caused by limited receiving aperture and migration artifacts resulting from wave propagation at the velocities of non original wave type. The migration method is applied successfully with model data, demonstrating that the new method is effective and correct.     

强震下的细木工板建筑材料承压特征分析

木质建筑材料承压特征在强震状态下呈现出较强的非线性特征,对其特征分析难度较大。以细木工板建筑材料为研究对象,提出强震下细木工板建筑材料承压特征分析方法。设计建筑材料承压模型,确定承压特征,据此进行特征提取。模拟强烈震动环境,设计对比实验,结合提取的细木工板建筑材料承压特征,进行精度、适用范围和PS点相位分析,有效避免强震下的非线性对建筑材料特征分析的影响。结果表明,强震下的细木工板建筑材料承压特征分析方法,可在最短时间内定位断裂发生位置、确定断裂位置承压等级,也可对细木工板建筑材料性能进行精准评估。     

适用于自然地表形变反演的小基线集方法

由于自然地表像元在长期观测中容易发生时空失相干,利用时序InSAR（Synthetic Aperture Radar Interferometry）技术对其开展形变监测会面临可用形变测量点不足的挑战。针对这一问题,提出一种改进的小基线（Small Baseline Subset,SBAS）方法。该方法改进了传统SBAS中初始高相干像元筛选及相位滤波过程：首先利用拟合优度检验,并结合相干性阈值条件来识别同质像元;然后根据同质像元数量将所有像元分成2部分,即PS（Persistent Scatterers）候选点和DS（Distributed Scatterers）候选点;其次分别在这两部分像元中开展初始高相干PS点及DS点筛选;最后对选出的高相干PS点及DS点进行加权相位滤波。利用覆盖北京平原区西北部（含城区及山区）的27景ENVISAT ASAR影像开展的形变监测实验表明：与2个参考方法相比,该方法能够有效扩展形变结果上的测量点数量和覆盖范围,测量点数量分别提高了22.6%及27.6%,且自然地表的形变测量点密度得到了明显提升。同时,研究区形变结果与4个连续GPS站的位移数据有很好的一致性,证明了该方法在地表形变反演中的有效性及优越性。     

月动力延伸预报产品在陕西月降水预测中的释用

应用1983-2005年国家动力气候模式产品,进行了月动力延伸预报产品解释应用预测试验。结果表明：月动力延伸预报产品解释应用对青藏高原东北侧的陕西地区月降水趋势有较好的预测能力,但夏、秋季PS评分较高,冬、春季PS评分较低,对大气环流季节突变月份预测的准确率具有不稳定性。     

天然地震转换波偏移成像方法

当地震波在层状介质中传播,P波通过速度界面时,会产生PP型折射波和PS型折射转换波．本文利用PS转换波与初至P波的到时差,提出一种不需要拾取P波和转换波震相的转换界面偏移成像方法．文中对三种不同的理论模型,在正演计算的基础上,采用了上述方法进行数值计算,计算结果表明,这种方法能够确定转换界面的位置和形态．这一方法的实现将有利于利用天然地震资料研究地球深部结构。     

波列振幅衰减测桩法的研究与应用(Ⅰ)--单桩竖向承载力的测定

通过研究打桩公式法和应力波动法(如CASE法),作者提出：用重锤或小型火箭筒一次冲击桩顶,用桩顶附近的检波器记录振波图和检测静、动位移,通过实测冲击能(总能量)转换系数、波动和振动各自消耗的能量等各物理量,测定计算单桩竖向承载力．利用振波图计算力(P)和位移(S)动态关系曲线、确定屈服点。并利用静载荷试验检验动测结果和确定动静PS曲线的相关常数,进而确定与承载力相应的沉降量。     

Subsidence mapping at regional scale using persistent scatters interferometry (PSI): The case of Tuscany region (Italy)

In this paper the mapping of subsidences in Tuscany (Italy) is presented. To achieve our goal satellite SAR data processed with persistent scatters interferometry (PSI) technique have been used. Several subsiding areas have been identified and three of them have been analyzed in detail and subsequently compared with literature work both to validate the results and to analyze the evolution of the identified subsidences. In general, this comparison confirmed the quality of the analyses and, furthermore, lead to the identification of an important ground uplift close to Prato city, an area that was historically affected by subsidence.     

Subsidence monitoring in coal area using time-series InSAR combining persistent scatterers and distributed scatterers

In coal mining areas, ground subsidence persistently happens, which produces serious environmental issues and affects the development of cities. To monitor the ground deformation due to coal mining, a modified time-series InSAR technique combining persistent scatterers (PSs) and distributed scatterers (DSs) is presented in this paper. In particular, DSs are efficiently identified using classified information and statistical characteristics. Furthermore, a two-scale network is introduced into traditional PSI to deal with PSs and DSs in a multi-layer framework by taking the advantage of the robust of PSs and the widely distribution of DSs. The proposed method is performed to investigate the subsidence of Huainan City, Anhui province (China), during 2012–2013 using 14 scenes of Radarsat-2 images. Experimental results show that the proposed method can ease the estimation complexity and significantly increase the spatial density of measurement points, which can provide more detailed deformation information. Result shows that there are obvious subsidence areas detected in the test site with subsidence velocity larger than 5 cm/year. The proposed method brings practical applications for non-urban area deformation monitoring.     

小基线集合成孔径雷达干涉测量算法及其应用

针对地理国情监测中地表形变监测研究不足的现状,文章在分析常规DInSAR特点及趋势性发展的基础上,结合地理国情监测的尺度特征与实际需求,给出了小基线集(SBAS-InSAR)算法原理;并比较了与永久散射体(PS-InSAR)算法的异同点;在此基础上,选取试验区,获取了COSMO-SkyMed雷达卫星数据,采用SBAS-InSAR算法,提取了试验区时间序列地表形变量与形变速率。结果表明:SBAS-InSAR算法可以利用比较适中的数据量获取到较高精度的反演结果,能够满足地理国情监测的实际需要,在地理国情监测中具有很好的适用性和可行性。     

交河故城瞭望台保护加固技术

交河故城遗址是第一批全国重点文物保护单位，瞭望台是交河故城内重要建筑遗址，它的主要病害是表面风化、裂隙密布、洞顶失稳。在分析病害形成机理的基础上，重点研究了生土遗址保护加固的几个关键技术，对掏蚀深度相对于悬挑土体厚度较小的土遗址，当基础掏蚀深度小于块体宽度的30 %时，可不采用砌补技术，只进行表面防风化处理；可选择竹木锚杆、PS-C浆液灌浆加固生土遗址，锚杆的单位锚固力可采用5 kN/m；采用新奥法加固洞顶可较好地保持文物原貌；西部干旱地区采用PS材料对土遗址进行防风化加固时应采用低浓度（小于5 %）、多次渗透的方式，迎风面渗透次数应不少于3遍，背风面应达4～5遍，并应合理选择施工时间。工程实践检验表明，这些保护技术取得了理想的加固效果。