下沉式抗滑桩与普通抗滑桩内力分析比较

通过将一组下沉式模型实验数据按照比例扩大到实际大小,建立计算模型,再利用地基系数法计算出桩身上的最大剪应力和最大弯矩。然后把模型中的下沉式抗滑桩换成普通抗滑桩,重新计算。通过比较计算结果,可以发现下沉式抗滑桩所独有的优越性,同时就这种特殊抗滑桩的适用性提出一些看法。     

酒泉早白垩世盆地群构造特征和成因

本文对酒泉盆地群充填物、早白垩世火山岩、早白垩世原型盆地构造样式和新生代反转构造的特征进行了分析,旨在查明酒泉原型盆地群的成因。初步认为,酒泉盆地群是早白垩世陆内热事件的表部响应,为近南北向或北东向裂谷盆地。在新生代,由于印度板块的挤压作用,北祁连山前展式北向推覆作用可能使早白垩世酒泉盆地群的南部地区转换为山脉,现今的盆地边界被掩覆在北祁连山之下;同时,印度板块的挤压作用还造成控制酒泉盆地群内部次级构造单元沉积体系的近南北向和北东向正断层转换为逆冲断层,盆地发生反转。     

全国水温台网井水温度2008年动态及其汶川地震前后的异常变化

在全面收集与系统分析全国水温台网近300口观测井2008年动态的基础上,梳理出井水温的正常年动态与固体潮,并进一步识别与分析2008-05-12汶川MS8.0地震震前、震时及震后的异常变化;归纳出全国井水温动态的正常年动态类型、特征及水温潮汐的基本特征,识别出汶川地震前14口井出现的异常,并分析该异常的形态与时空分布特征;分析125口井的同震响应与震后变化特征,进一步论证利用井水温动态监测地震前兆的可能性与存在的问题,提出把现有的水温观测网进一步改造与升级、开拓地壳热动态与地震活动关系观测与研究的创新思路。     

汤加、日本、伊豆-小笠原与马里亚纳海沟俯冲板块正断层模拟：对俯冲板块弱化的影响

通过对比实际观测与弹塑性变形模型,研究了沿着汤加、日本、伊豆-小笠原、马里亚纳海沟的板块挠曲与正断层特征。观测表明,平均海沟挠曲量在日本海沟最小（3公里）,马里亚纳海沟最大（4.9公里）,而平均正断层垂直断距在日本海沟最小（113米）,汤加海沟最大（284米）。模拟了俯冲板块在三种构造加载的作用下发生弯曲变形并产生正断层的过程：垂向加载（V₀）、弯矩（M₀）和水平拉张力（F₀）。在板块挠曲与正断层特征的双重约束下,反演得到了四个海沟的最佳模型解。结果显示,日本海沟的水平张力分别比马里亚纳、汤加和伊豆-小笠原海沟小33%、50%和60%。汤加、日本、伊豆-小笠原、马里亚纳海沟的正断层最深可达海底以下29,23,32和32公里,这与重新定位后的日本与伊豆-小笠原地震深度一致。此外,反演得到的水平张拉力与观测到的平均垂直断距呈一定正相关性,而计算得到的有效弹性厚度减少量与观测到的海沟挠曲量也相关。这些结果表明,水平张拉力在正断层发展过程中起着关键控制作用,板块弱化可导致板块挠曲量的显著增加。     

利用中级地震激发的自由振荡简振模研究我国大陆中部地区上地幔介质横向特性

选取2004~2015年发生在我国大陆附近的14个中级地震(6.5相似文献   

在二维应力状态下土体地震动偏应力的特征

地震作用在土体中产生的动偏应力包括动水平剪应力τｖｈ 和动正应力差［σｐ － σｈ］ ／２ 。本文讨论了这两种动偏应力分量之间相互变化的关系     

Estimating the thickness of a faulted mechanical layer based on fault spacing: An example from Miyako‐jima Island,southern Ryukyu Arc,Japan

The thickness of the mechanical layer that hosts a group of faults can be estimated from the spacing of saturated faults (i.e. the constant spacing between faults when the fault system is fully developed and has attained its final fault density). We measured fault spacing for a group of saturated active normal faults on Miyako‐jima Island (southern Ryukyu Arc, Japan) and estimated the thickness of the faulted mechanical layer. The measured fault spacing is 1.30 ±0.14 km, and the thickness of the mechanical layer is < 3 km, which is the upper limit of the seismogenic zone. This faulted mechanical layer corresponds to a sedimentary layer in which earthquakes cannot occur. Results indicate that the shallow (< 3 km depth) normal faults on Miyako‐jima Island do not have the potential to cause medium‐size earthquakes as individual faults. The origin of the shallow normal faults might be related to the presence of a larger‐scale, deeper fault. The results indicate that fault spacing provides important information on the potential magnitude of earthquakes associated with active faults.     

Velocity profiles and basal stresses in natural debris flows

The internal deformation within debris flows holds essential information on dynamics and flow resistance of such mass-wasting processes. Systematic measurements of velocity profiles in real-scale debris flows are not yet available. Additionally, data on basal stresses of the solid and the fluid phase are rare. Here, we present and analyse measurements of vertical velocity profiles in two debris flows naturally occurring in the Gadria Creek, Italy. The method is based on cross-correlation of paired conductivity signals from an array of sensors installed on a fin-shaped wall located in the middle of the channel. Additionally, we measure normal stress and pore fluid pressure by two force plates with integrated pressure transducers. We find internal deformation throughout the flows. Only at the very front was some en-bloc movement observed. Velocity profiles varied from front to tail and between flows. For one debris flow, pore fluid pressure close to normal stress was measured, whereas the other flow was less liquefied. The median shear rates were mostly less than 5 s⁻¹ and Savage numbers at the basal layer ranged from 0.01 to 1. Our results highlight the variable nature of debris flows and provide quantitative data on shear rate and basal stress distribution to help guide model development for hazard assessment and landscape evolution. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.     

湖南锡田钨锡多金属矿田燕山期NE向断层演化历史及其成矿意义

为了确定湖南锡田矿田燕山期NE向断层演化历史、蚀变特征及与钨锡成矿关系本文调查了矿田内燕山期断层野外宏观特征,对断层中充填石英脉进行了显微鉴定、阴极发光、含矿元素分析,结果显示:(1)断层以NE60°～70°平行分布于茶汉盆地南北两侧,均倾向茶汉盆地,断层的陡倾、棱角状角砾及梳状石英等指示了断层的张性性质;(2)断层经...     

��ʷ���Լ����Ϣ�µ�����վGPS���ǹ��ȷ��

????й????????????λ??????????????GNSS????????????????????????????????????GPS?????????????????,??????÷????????????????????????????????????????????????????IGS???????????????????????????￡??????й??????????????????????????÷???????Ч?????????