双孕镶金刚石钻头跟套管连续钻进机构设计及模拟分析

跟管钻进技术是解决复杂地层钻进的有效方法之一,针对跟管钻进过程中内外管环空间隙卡阻、钻具受力复杂、能耗大和套管连续下入深度有限、深孔干热岩花岗岩在热应力作用下破碎卡钻等技术难题,本文创新设计了一种双孕镶金刚石钻头跟套管连续钻进机构。理论分析表明：双钻头同心回转钻进岩屑小,避免内外管卡阻,极大地改善了钻具的受力状态,降低了钻具发生断裂的风险;内钻头通过齿轮啮合方式带动外钻头独立回转,相较于常规跟套管钻进能量消耗降低29.29%;外钻头采用高胎体交替式结构,有效避免了钻井液局部循环现象的发生,从而提高了套管连续下入的深度。该机构设计为跟套管钻进技术提供了一种新思路。     

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.     

Sloped multi‐roller isolation devices for seismic protection of equipment and facilities

The rolling motion of mutually orthogonal rollers respectively sandwiched between two bearing plates in which one or both have V‐shaped sloping surfaces makes the sloped rolling‐type isolation device have an excellent in‐plane seismic isolation performance. In this study, the sloped rolling type isolation device in which a single roller moves between two V‐shaped sloping surfaces along each principle horizontal direction is refined by incorporating multi‐roller, built‐in damping, and pounding prevention mechanisms. The associated dynamic behavior is further clarified, and a simplified twin‐flag hysteretic model, which can be easily applied in most commercial computational tools is then proposed. Seismic simulation tests on the refined isolation devices (i.e. the sloped multi‐roller isolation devices) with different design parameters such as sloping angles of bearing plates and built‐in damping capabilities, together with a raised floor system by employing the sloped multi‐roller isolation devices, were conducted. Not only is the efficiency of the sloped multi‐roller isolation devices in seismically protecting the important objects, but also the practicability and accuracy of the proposed simplified numerical model in predicting the seismic responses of the sloped multi‐roller isolation devices is experimentally verified. Copyright © 2014 John Wiley & Sons, Ltd.     

苏州与上海孪生城市模式的形成机理及其区域效应

在对美国进行大量实证分析的基础上,艾伦从理论上推导出的孪生城市模式丰富和发展了区域空间结构理论。1990年代以后,苏州在跨国公司投资作用下的快速崛起,已与上海初步构成了一种功能上互补的共生关系,即孪生城市模式。这一模式的形成主要导源于以下两方面的原因。从行政原因上看,苏州与上海由于分属两个省级行政单元,经营成本、产业政策自1980年代以来一直有着较为明显的差异;从经济原因上看,苏州与上海仅距不到90 km、位居上海都市圈的内圈层,且离虹桥机场约50 km。苏州的快速崛起以至于苏沪孪生城市的形成,产生了多方面的区域效应。苏州与无锡本是一对水平相当、产业性质类似的城市,现已出现了明显的差异化发展态势,从而为在此基础上城市合理分工的形成奠定了基础;苏州位居省级行政单元的交界,因此苏州与作为省会城市的南京构成了广义上的双核结构模式;上述因素的综合作用,使得我们可以构建起沪宁沿线城市合理分工的多重空间组合模式。     

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。     

The impact of ocean data assimilation on seasonal predictions based on the National Climate Center climate system model

An ensemble optimal interpolation (EnOI) data assimilation method is applied in the BCC_CSM1.1 to investigate the impact of ocean data assimilations on seasonal forecasts in an idealized twin experiment framework. Pseudo-observations of sea surface temperature (SST), sea surface height (SSH), sea surface salinity (SSS), temperature and salinity (T/S) profiles were first generated in a free model run. Then, a series of sensitivity tests initialized with predefined bias were conducted for a one-year period; this involved a free run (CTR) and seven assimilation runs. These tests allowed us to check the analysis field accuracy against the “truth”. As expected, data assimilation improved all investigated quantities; the joint assimilation of all variables gave more improved results than assimilating them separately. One-year predictions initialized from the seven runs and CTR were then conducted and compared. The forecasts initialized from joint assimilation of surface data produced comparable SST root mean square errors to that from assimilation of T/S profiles, but the assimilation of T/S profiles is crucial to reduce subsurface deficiencies. The ocean surface currents in the tropics were better predicted when initial conditions produced by assimilating T/S profiles, while surface data assimilation became more important at higher latitudes, particularly near the western boundary currents. The predictions of ocean heat content and mixed layer depth are significantly improved initialized from the joint assimilation of all the variables. Finally, a central Pacific El Ni?o was well predicted from the joint assimilation of surface data, indicating the importance of joint assimilation of SST, SSH, and SSS for ENSO predictions.     

地下水位循环变化时隧道开挖对群桩的长期影响研究

为解决地下水位随季节升降变化时隧道开挖对邻近桩基的长期影响难题,通过三维离心模型试验,研究了地下水位循环变化时隧道对群桩的长期影响。主要分析水位循环变化时地表长期沉降、桩顶长期附加沉降、桩身长期附加弯矩和附加轴力的变化规律。试验结果表明：在隧道附近,地下水位循环变化尤其是降水对地表长期沉降影响更为明显。地表长期附加沉降随着地下水位循环次数增加而增大,且呈衰减式变形,即使经过3次水位升降循环也不能稳定;桩基长期附加沉降显著,其附加沉降量占总沉降量的50%以上;前、后桩的长期附加轴力基本为正值,桩总轴力增加,对既有受压桩极为不利,附加轴力拐点位置及最大值有所区别;经过3次地下水位循环变化后,前、后桩桩身弯矩反弯点个数减少,但桩身最大附加弯矩均明显变大,当达到极限弯矩,桩身出现塑性铰,这对穿越厚软弱层地基中的既有受压柔性桩极为危险。     

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。