榆林地区黄土窑洞崩塌灾害的多发性原因及其防治对策研究     

缪祥生  韩许恒 《地球科学与环境学报》1993,(3)

本文通过对榆林地区米脂、绥德、子洲、清涧、吴堡和榆林市黄土窑洞建窑环境进行考察,总结分析了在黄土介质中修建的土窑洞崩塌灾害多发性原因,并提出了可操作性的防治对策。该对策可广泛适用于我国黄土窑洞分布区。  相似文献   

Stress and displacement fields due to a penny-shaped shear crack with non-uniform traction     

Niu Zhiren 《Geophysical Journal International》1988,94(2):219-235

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某滑坡稳定分析及处理方案探讨   总被引：1，自引：1，他引：0  

毛新虎 《地球科学与环境学报》2003,25(2):22-26

滑坡属于不良地质现象,是斜坡上的部分岩体和土体在自然或人为因素的影响下沿某一明显的界面发生剪切破坏向坡下运动的现象。当高速公路不得不通过某一滑坡时,对其稳定性进行分析和整治设计就显得尤为重要。以祁临高速公路灵石至霍州段窑深沟大桥东南窑深沟滑坡为实例,根据勘察资料,利用岩土力学知识,在公路修好后并运行的情况下,计算出了其稳定系数和推滑力,又以材料力学、结构力学等力学理论为基础,设计出抗滑桩和锚索抗滑桩等两种整治方案,经验证,效果良好。  相似文献   

A Continuum Theory For Lattice Preferred Orientation     

Neil M. Ribe 《Geophysical Journal International》1989,97(2):199-207

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Average slip rate,earthquake rupturing segmentation and recurrence behavior on the Litang fault zone,western Sichuan Province,China   总被引：3，自引：0，他引：3  

XU Xiwei  WEN Xueze  YU Guihua  ZHENG Rongzhang  LUO Haiyuan & ZHENG Bin . Institute of Geology  China Earthquake Administration  Beijing  China  . Earthquake Administration of Sichuan Province  Chengdu  China 《中国科学D辑(英文版)》2005,48(8):1183-1196

The Litang fault zone (LFZ) is an important active fault within the northwestern Sichuan sub-block. To-gether with the Garzê-Yushu, Xianshuihe, and An-ninghe fault zones on its northern, eastern and south-eastern sides, the LFZ constitutes the lateral extrusion tectonic system in the southeastern part of the Qing-hai-Tibetan Plateau[1,2] (Fig. 1). According to instru-mental records, historical recordings and field investi- gation, an earthquake (Ms7.3) occurred on its middle to south se…  相似文献   

GPS多路径效应实例计算与分析   总被引：2，自引：1，他引：1  

郭杭  余敏  薛光辉 《测绘科学》2006,31(5):95-96,56

本文讨论了一个GPS伪距多路径值计算及其频谱分析的方法。文中首先介绍了GPS多路径试验测量和观测数据采集的程序。然后探测和修复周跳、再利用伪距多路径计算公式,获得GPS测量中的伪距多路径值。实例证明该方法有效地计算出了伪距多路径值。  相似文献   

Ultrahigh temperature deformation microstructures in felsic granulites of the Napier Complex, Antarctica   总被引：3，自引：0，他引：3  

Majbritt D. Lund  Sandra Piazolo  Simon L. Harley 《Tectonophysics》2006,427(1-4):133

Detailed electron microscope and microstructural analysis of two ultrahigh temperature felsic granulites from Tonagh Island, Napier Complex, Antarctica show deformation microstructures produced at  1000 °C at 8–10 kbar. High temperature orthopyroxene (Al 7 wt.% and  11 wt.%), exhibits crystallographic preferred orientation (CPO) and frequent subgrain boundaries which point to dislocation creep as the dominating deformation mechanism within opx. Two different main slip systems are observed: in opx bands with exclusively opx grains containing subgrain boundaries with traces parallel to [010] and a strong coupling of low angle misorientations (2.5°–5°) with rotation axes parallel to [010] the dominating slip system is (100)[001]. Isolated opx grains and grain clusters of 2–5 grains embedded in a qtz–fsp matrix show an additional slip system of (010)[001]. The latter slip system is harder to activate. We suggest that differences in the activation of these slip systems is a result of higher differential stresses imposed onto the isolated opx grains and grain clusters. In contrast to opx, large qtz grains (up to 200 μm) show random crystallographic orientation. This together with their elongate and cuspate shape and the lack of systematic in the rotation axes associated with the subgrain boundaries is consistent with diffusion creep as the primary deformation mechanism in quartz.Our first time detailed microstructural observations of ultrahigh temperature and medium to high pressure granulites and their interpretation in terms of active deformation mechanisms give some insight into the type of rheology that can be expect at lower crustal conditions. If qtz is the mineral phase governing the rock rheology, Newtonian flow behaviour is expected and only low differential stress can be supported. However, if the stress supporting mineral phase is opx, the flow law resulting from dislocation creep will govern the rheology of the rock unit; hence, an exponential relationship between stress and strain rate is to be expected.  相似文献   

星载GPS载波相位周跳探测方法   总被引：1，自引：0，他引：1  

郭淑艳  郭金运  张莉娜 《测绘科学》2006,31(4):54-56

在星载GPS载波相位测量中,周跳的探测与修复对最后的定位精度起着至关重要的作用。本文根据在星载条件下GPS载波相位测量的观测时间短、环境变化复杂、所得历元少和基本不受对流层延迟影响等特点,论述了适用于星载高动态环境GPS载波相位周跳探测和修复的方法,并指出各种方法的特点和适用要求。  相似文献   

实时修复双频原始载波相位观测值周跳的虚拟值探测法     

伍岳  李海军  邱蕾  王海军 《武汉大学学报(信息科学版)》2012,37(3):257-260

利用各频率观测值间物理上的相关性,采用数学变换得到一个含有双频原始载波观测信息的虚拟观测值,与双频数据按长波长特性进行多频组合来放大周跳。对探测出的周跳候选值利用Melbourne-Wubbena组合及多项式拟合作为两个判别条件来进行甄选,达到了实时修复双频原始载波相位观测值周跳的目的。  相似文献   

GNSS精密单点定位中的实时质量控制   总被引：2，自引：1，他引：1  

张小红  郭斐  李盼  左翔 《武汉大学学报(信息科学版)》2012,37(8):940-944,1013

提出了一套适用于GNSS精密单点定位(PPP)的实时质量控制方法,重点研究了钟跳探测与修复、周跳探测与标记、抗差估计方法,并在现有质量控制方法的基础上进行了改进。对比分析了不同质量控制方案对PPP的影响,结果表明,钟跳不利于周跳探测,严重影响非差PPP的精度和效率,必须对其进行探测与修复;联合MW、GF组合可以探测出绝大多数周跳,且较使用单一方法更为准确、可靠;采用改进的抗差估计有效抑制了残余粗差对精密定位的影响,显著提高了PPP的精度和可靠性。  相似文献