NNR constraint in ITRF2000 and the new global plate motion model NNR-ITRF2000VEL

There are 54 sites employed by ITRF2000 for ITRF2000 orientation. The deficiencies are obvious. First, these sites cannot well represent the rotation rate of the earth crust because there is no selected site in five out of fourteen tectonic plates and three of fourteen plates only have one site each. Second, the total angular momentum of the crust is non-vanishing in ITRF2000, even though it is declared that No Net Rotation (NNR) with respect to NNR-NUVEL1A is imposed on ITRF2000 construction according to the documentations of ITRF2000. So the NNR condition in conventional terrestrial reference system (CTRS) realization cannot be satisfied in ITRF2000. In this paper, the criteria of site selection for estimating the Euler vectors are suggested; the Tisserand system constraint equation in ITRF construction is derived; and as a product, the global plate motions can be obtained from the ITRF2000 construction.     

现代城市数字测图方法浅析

本文分析比较了目前城市大比例尺数字化测图中主要方法的优缺点，并为实现数字化地形图中不连续线、面状符号及复杂线状符号向GIS的自动化导入，针对电子平板法提出了基础线的概念。对全站仪草图法，提出在全站仪上加挂微型计算机，并用常规摄像方法代替草图。     

Papua New Guinea Highlands: palaeomagnetic constraints on terrane tectonics

Oblique convergence since the Early Cenozoic between the northward-moving Australian plate, westward-moving Pacific plate and almost stationary Eurasian plate has created a world-ranking tectonic zone in the eastern Indonesia–New Guinea–Southwest Pacific region (Tonga–Sulawesi megashear) that is notorious for its complex mix of tectonic styles and terrane juxtapositions. Unlike an ancient analog—the Mesozoic–Cenozoic Cordillera of North America—palaeomagnetic constraints on terrane motions in the zone are few. To improve the framework of quantitative control on such motions and therefore our understanding of the development of the zone, results of a palaeomagnetic study in the Highlands region of Papua New Guinea (PNG), in the southern part of the New Guinea Orogen, are reported. The study yields new insights into terrane tectonics along the Australian craton's active northern margin and confirms the complexity of block rotations to be expected at the local scale in tectonically intricate zones. The study is based on more than 500 samples (21 localities) collected from an interior and an exterior zone of New Guinea's central cordillera. The two zones are separated by the Tahin and Stolle–Lagaip–Kaugel Fault zones and collectively represent the para-autochthonous northern margin of the Australian craton. Samples from the interior zone, which in the study area comprises a cratonic spur of uncertain—probably displaced—origin, come from Triassic to Miocene sediments and subordinate volcanics of the Kubor Anticline, Jimi Terrane, and Yaveufa Syncline (16 localities) in the central and eastern Highlands. Samples from the exterior zone, which represent a basement-involved, Pliocene foreland fold-and-thrust belt, come from Middle Eocene to Middle Miocene carbonates and clastics (five localities) in the southern Highlands of the Papuan Fold Belt. Results permit us to constrain the tectonic evolution of the two zones palaeomagnetically. Using mainly thermal demagnetization techniques, three main magnetic components have been identified in the collection: (1) a recent field overprint of both normal and reverse polarity; (2) a pervasive overprint of mainly normal polarity that originated during extensive Middle to Late Miocene intrusive activity in the central cordillera; and (3) a primary component which has been identified in only 7 of the 21 localities (5 of 11 stratigraphic units represented in the collection). All components show patterns of rotation that are consistent within the zones, but differ between them. In the interior zone (central and eastern Highlands), large-scale counterclockwise rotations of between 30°+ and 100°+ have been established throughout the Kubor Anticline and Jimi Terrane, with some clockwise rotation present in the southern part of the Yaveufa Syncline. In contrast, in the Mendi area of the exterior zone (southern Highlands), clockwise rotations of between 30°+ and 50°+ can be recognized. These contrasting rotation patterns across the Tahin and Stolle–Lagaip–Kaugel Fault zones indicate decoupling of the two tectonic zones, probably along basement-involved faults. The clockwise rotations in the southern Highlands of the Papuan Fold Belt are to be expected from its structural grain, and are probably governed by regional basement faults and transverse lineaments. In contrast, the pattern of counterclockwise rotations in the Kubor Anticline–Jimi Terrane cratonic spur of the central and eastern Highlands was unexpected. The pattern is interpreted to result from non-rigid rotation of continental terranes as they were transported westward across the northeastern margin of the Australian craton. This margin became reorganised after the Middle Miocene, when the steadily northward-advancing Australian craton impinged into the westward-moving Pacific plate/buffer-plate system. Transpressional reorganisation under the influence of the sinistral Tonga–Sulawesi megashear became enhanced with Mio-Pliocene docking, and subsequent southward overthrusting, of the Finisterre Terrane onto the northeastern margin of the Australian craton.     

平板载荷试验应思考的几个问题

提出了平板载荷试验中的几个问题:(1)复合地基平板载荷试验垫层的重要性;(2)复合地基平板载荷试验存在尺寸效应;(3)单墩或单桩平板载荷试验不完善。重点对目前广泛使用的复合地基荷载试验进行了讨论,以引起检测人员注意。     

长效振弦式锚索测力计应用研究

介绍了长效振弦式锚索测力计传感器的工作原理、结构特点、技术性能和配套仪器,并对主要相关技术的应用研究成果作了论述:(1)弱激发电路解决频率不一致问题;(2)微小变形原则解决长期稳定性问题;(3)新数学模型提高了传感器准确度,二次仪表提高了传感器准确度。     

溪洛渡水电站坝址区岩体蠕变特性试验研究

介绍了溪洛渡水电站坝址区岩体柔性板法蠕变试验方法及试验结果,给出了岩体蠕变模型及其参数,为工程设计提供了参考依据。     

兴山县龙王嘴边坡稳定性分析与加固设计

龙王嘴边坡系坡高达70 m、坡角达70 °的高陡岩质边坡。分析了宜-秭公路石峡段龙王嘴高边坡变形的地质条件,在定量评价龙王嘴高边坡稳定性的基础上,进行了该高边坡的施工图加固设计。根据其特点将350 m长的坡段分为A,B,C三个区,分别采取预应力锚索与锚杆加固、挂网喷射混凝土支护和喷射混凝土支护等措施,实践证明,工程治理效果良好。     

中国大陆地震构造研究回顾

简要回顾了近4年来(1999～2002年)我国在地震构造方面研究的进展，重点介绍了在地壳上地幔结构、活动断裂和大地震构造背景、地壳形变和数值模拟方面的工作．在我国境内发生的绝大多数地震都属于大陆地震的范畴，因此,中国地震学家把研究的重点放在大陆地震上．中国在九五期间完成的中国数字地震观测系统和中国地壳运动观测网络重大科学工程为地震构造的研究提供了大量的基础资料．因此，４年来的地震构造研究取得了相当大的进展．      

任意载荷激励下直角三角形板单元局部动力效应

本文推导了在任意载荷激励下直角三角形板单元局部动力效应修正公式。采用单边积分法，对单元边上的单位宽度上的内力进行局部动力修正，代替以往的用加密网格提高精度的方法。计算结果表明，局部动力效应影响不可忽略，本文方法可使计算结果更为精确。这对分析大型复杂结构环境载荷激励下的局部动力效应具有参考价值。     

两结构高效阻尼控制体系试验研究

本文通过模拟地震动振动台试验，研究了两个相邻结构模型的地震响应，结构模型采用一种高效阻尼装置(High Efficient Damper for Multi—Structure System即HEDMS)连接。非线性时程分析与振动台试验结果都证明了该阻尼装置能高效发挥软钢阻尼器的耗能能力，从而显著减轻两结构模型的地震响应。同时，研究还指出了进行阻尼装置设计时应该注意的一些问题。