水泥土(砼)抗压试件尺寸表面约束对强度的影响

推导了圆柱体试件和长（立）方体试件,分别在不同表面摩擦力和不同高宽（径）比下基于双剪屈服准则下抗压强度的理论计算公式,并与实验结果比较所得结果与实验结果甚为吻合。其理论计算与实验结果都说明,试件尺寸的不同与表面抹油与否对水泥土抗压强度均有一定的影响。其高宽（径）越大,其强度越低且越趋于一定值。试件上下表面不摸油其抗压强度略高抹油情况。     

Paleostress reconstructions based on calcite twins in the Joseon Supergroup, northeastern Ogcheon Belt (South Korea)

Abstract   Paleostress of the Joseon Supergroup in the northeastern part of the Ogcheon Belt, South Korea, is reconstructed in the Jecheon–Danyang area with the help of calcite twinning. In the study area, the average twin thickness and intensity increase with the total twin strain increase. From the appearance of twins, the average twin thickness and intensity, and the total twin strain, it is estimated that calcite twins were produced under temperatures lower than 200°C. The maximum shortening axis in the study area changes orientation from northeast–southwest to NNW–SSE or northwest–southeast, and finally to north–south. We suggest these three distinct stages with different orientations of the maximum shortening axis can be correlated with: (i) the Paleozoic to Early Jurassic Songrim orogeny; (ii) the Early Jurassic to Late Jurassic Daebo orogeny; and (iii) the Cretaceous Bulgugsa orogeny.     

虚拟地理环境在智慧城市中的研究与应用

智慧城市是数字城市的升级版,其管理服务的动态实现与虚拟地理环境联系紧密。本文首先综述了虚拟地理环境的概况;然后对虚拟地理环境运用在智慧城市中的关键技术作了归纳,分析了三维动态仿真、虚实交互、多智能体、数字孪生技术的特点及其在智慧城市管理中的适用范围;进而从应用的角度分析了虚拟地理环境在智慧城市中的研究现状与存在的挑战;最后总结出在人工智能和VR新时代下,虚拟地理环境在智慧城市中实时显示、高效算法、虚实交互等方面的发展前景。     

区域地球系统模式研究进展

区域地球系统模式是区域气候模式下一阶段的主要发展目标。本文阐述了发展区域地球系统模式的重要意义,分析了近年来区域地球系统模式的研究进展和典型案例,指出其多圈层通量耦合、空间分辨率提高以及耦合数据同化的三个共性特征。建议以开源共创的方式整合各界研究力量,加快建设我国自主可控的区域地球系统模式;围绕新建立的模式开展跨学科研究,特别关注其中多圈层、多尺度过程的相互作用;围绕高分辨率区域地球系统模式建立区域数字孪生监测预警平台,用于关键区域的防灾减灾和关键决策支撑。     

Inversion of calcite twin data,paleostress reconstruction and multiphase weak deformation in cratonic interior – Evidence from the Proterozoic Cuddapah basin,India

Paleostress orientations from mechanically twinned calcite in carbonate rocks and veins in the neighborhood of large faults were investigated to comment on the nature of weak upper crustal stresses affecting sedimentary successions within the Proterozoic Cuddapah basin, India. Application of Turner's P–B–T method and Spang's Numerical dynamic analysis on Cuddapah samples provided paleostress orientations comparable to those derived from fault-slip inversion. Results from the neighborhood of E–W faults cutting through the Paleoproterozoic Papaghni and Chitravati groups and the Neoproterozoic Kurnool Group in the western Cuddapah basin, reveal existence of multiple deformation events − (1) NE–SW σ₃ in strike-slip to extensional regime along with an additional event having NW–SE σ_3, for lower Cuddapah samples; (2) compressional/transpressional event with ESE–WNW or NNE–SSW σ₁ mainly from younger Kurnool samples.Integrating results from calcite twin data inversion, fault-slip analysis and regional geology we propose that late Mesoproterozoic crustal extension led to initial opening of the Kurnool sub-basin, subsequently influenced by weak compressional deformation. The dynamic analysis of calcite twins thus constrains the stress regimes influencing basin initiation in the southern Indian cratonic interior and subsequent basin inversion in relation to craton margin mobile belts and plausible global tectonic events in the Proterozoic.     

任意晶系中非180°取向畴的矩阵分析

利用线性变换的方法，推导出三斜晶系中绕任意方向旋转任意角度的空间点阵基矢间的变换矩阵，给出了变换矩阵在四方晶系中的表达式并分析了ZrO2中的两种取向畴。     

Phillipsite in deep-sea sediments

Ｐｈｉｌｌｉｐｓｉｔｅｉｎｄｅｅｐ－ｓｅａｓｅｄｉｍｅｎｔｓ￥ＰｅｎｇＨａｎｃｈａｎｇａｎｄＬｉｕＺｈｅｎｇｋｕｎ（ＲｅｃｅｉｖｅｄＭａｒｃｈ５，１９９３；ａｃｃｅｐｔｅｄＡｕｇｕｓｔ１４，１９９３）Ａｂｓｔｒａｃｔ：──Ａｐｈｉｌｌｉｐｓｉｔｅａｓ...     

大理岩脆-韧性转换变形实验研究

本文利用两组大理岩岩样进行脆-韧性变形有实验，一组在室温条件，围压变化范围为20-400MPa；另一组围压为50MPa，温度变化范围为15-200℃。前者发生脆-韧性转换的围岩范围为50-400MPa，其中变形最敏感的围压为50-150MPa，脆-韧性转换过程表现为应变硬化作用；后者发生脆-韧性转换的温度为50-200℃，其中变形最敏感的温度为100℃左右，脆-韧性转换过程表现为应变软化作用为主。在变形（实验）岩样宏观变形行为和微观构造特征分析的基础上，讨论了岩石脆-韧性转换变形的若干标志（包括力学性质、宏观变形行为和显微构造标志等），并阐明了大理岩脆-韧性转换变形方式是以微破裂、晶内滑移和碎裂流动作用为主。这些实验研究结果对于地壳中浅层次构造变形及表层构造软弱带成因研究肯有重要意义。     

盾构法隧道施工对邻近摩擦单桩影响的研究

采用对隧道洞室周边及开挖面的土体施加由盾构机引起的各种荷载的方法模拟盾构施工,通过变化隧道埋深、隧道数量及开挖顺序研究盾构法开挖隧道对邻近摩擦单桩的影响。计算结果表明,隧道与桩的水平距离不变时,隧道埋深存在一个临界值,当隧道埋深为此临界值时隧道开挖引起的桩顶沉降、桩身侧移最大;隧道埋深较小时,隧道开挖会使桩产生较小的上移;隧道与桩的水平距离缩小相同值时,隧道埋深越小,开挖引起的桩顶沉降增加量越大;双隧道开挖引起的桩顶最终沉降量大于单隧道开挖引起的桩顶最终沉降量;双隧道同时开挖引起的桩顶沉降量、桩顶最大侧移大于双隧道先后开挖引起的桩顶沉降量、桩顶最大侧移;无论是同时开挖还是先后开挖,垂直双隧道引起的桩顶沉降量明显小于平行双隧道引起的桩顶沉降量。     

广义非线性强度理论体系

广义非线性强度理论用一个表达式统一描述各种材料在 平面及子午面上的非线性强度特性,形成了一个全新的非线性强度理论系统,使非线性强度理论从适用于某一类特定材料的单一非线性强度理论发展到可以适用于众多不同材料的广义非线性强度理论,完善了强度理论体系。广义非线性强度理论包含了一系列现有的和可能有的单一非线性强度理论,如Mises准则、SMP准则等。利用土、岩石和混凝土强度试验结果验证了广义非线性强度理论适用于多种材料的优越性。