Timoshenko beam solution for the response of existing tunnels because of tunneling underneath

An analytical solution for the deflection and internal forces of an existing tunnel because of tunneling underneath is presented. The existing tunnel is modeled as a Timoshenko beam resting on a Winkler foundation, which takes into account the contribution of shear deformation to the total deflection of the existing tunnel. The validity of the analytical solution is verified by a centrifuge test, and the merit of this analytical method is confirmed by comparison with the conventional Euler–Bernoulli beam model. Influential factors on the behavior of the existing tunnel are investigated by consideration of the variations of subgrade modulus, ground loss induced by the new tunnel construction, vertical clearance between the new tunnel and the existing tunnel, and relative existing tunnel–soil stiffness. Results show that the proposed analytical method is a valid and effective method to evaluate shearing‐induced deformation in existing tunnels with large diameters. Results also show that the pattern and the amplitude of the response of the existing tunnel are affected largely by ground loss induced by the new tunnel construction, vertical clearance between the new tunnel and the existing tunnel, and relative existing tunnel–soil stiffness. Copyright © 2015 John Wiley & Sons, Ltd.     

西北某拟建水库渗漏分析

水库渗漏会造成多方面的影响,因此其渗漏量的大小往往决定了建坝的资金,甚至水库的修建与否。分析了西北某拟建水库坝区的渗漏情况,并计算了其渗漏量大小,对将来的建坝可起到一定的指导作用。     

川滇断块东界中段地区现代地壳形变和断裂现今活动

采用加权秩亏动态平差方法和变形分析方法，对川滇菱形断块及其附近的精密水准资料，测角、测边资料进行系统计算处理，并结合跨断层短水准、动态蠕变测量资料处理结果，论述了该区域的地壳形变特征和地震危险性。     

The Effects of Different HITRAN Versions on Calculated Long-Wave Radiation and Uncertainty Evaluation

Four editions of the High Resolution Transmission (HITRAN) databases (HITRAN96, HITRAN2K, HITRAN04, and HITRAN08) are compared by using a line-by-line (LBL) radiative model in the long-wave calculation for six typical atmospheres. The results show that differences in downward radiative fluxes between HITRAN96 and HITRAN08 at the surface can reach a maximum of 1.70 W m 2 for tropical atmospheres. The largest difference in heating rate between HITRAN96 and HITRAN08 can reach 0.1 K day 1 for midlatitude summer atmosphere. Uncertainties caused by line intensity and air-broadened halfwidths are also evaluated in this work using the uncertainty codes given in HITRAN08. The uncertainty is found to be 1.92 W m 2 for upward fluxes at the top of the atmosphere (TOA) and 1.97 W m 2 for downward fluxes at the surface. The largest heating rate caused by the uncertainty of line intensity and air-broadened half-width can reach 0.5 K day 1 . The differences in optical depths between 1300 and 1700 cm 1 caused by different HITRAN versions are larger than those caused by the uncertainties in intensity and air-broadened half-width. This paper suggests that there is inaccurate representation of line parameters over some spectral ranges in HITRAN and more attention should be paid to these ranges in fields such as remote sensing.     

Metallogeny and environmental impact of Hg in Zn deposits in China

Zinc smelting is currently regarded as one of the most important atmospheric Hg emission sources in the world. In order to assess the potential environmental impacts of Hg from Zn smelting in China, the distribution of total Hg concentration (HgT) in Zn concentrates (ZCs) from 100 Zn deposits in China was investigated. It was found that HgT varies depending on the ore types and their geneses. Zinc concentrates from sedimentary-exhalative deposits (SEDEX, geometric mean = 48.2 μg/g) have the highest HgT. The possible explanation is that the sources of mineralizing solutions for SEDEX deposits are deep formational brines in contact with sedimentary rocks, and there are much higher background Hg contents in sedimentary rocks. Zinc concentrates from volcanic hosted massive sulfide deposits (VMS, geometric mean = 11.5 μg/g) and Mississippi Valley-Type (MVT, geometric mean = 10.1 μg/g) deposits have intermediate HgT. VMS may receive most of their Hg from fluid–rock interaction and/or by direct input of gaseous Hg from a mantle source. However, the source of metals within MVTs may be the low-temperature hydrothermal solution formed by diagenetic recrystallization of the carbonates. Intrusion related deposits (IRs) have the lowest HgT (Geomean = 2.4 μg/g), and the dispersion of Hg in the IRs seems to be influenced by the temperature of ore formation and/or the nature of wall–rock alteration. Finally, it was estimated that the annual Hg emission to the atmosphere from Zn smelting in China was about 107.7 tons in 2006.     

A Simplified Numerical Approach for the Prediction of Rainfall-Induced Retrogressive Landslides

Retrogressive landslides are common geological phenomena in mountainous areas and on onshore and offshore slopes. The impact of retrogressive landslides is different from that of other landslide types due to the phenomenon of retrogression. The hazards caused by retrogressive landslides may be increased because retrogressive landslides usually affect housing, facilities, and infrastructure located far from the original slopes. Additionally, substantial geomorphic evidence shows that the abundant supply of loose sediment in the source area of a debris flow is usually provided by retrogressive landslides that are triggered by the undercutting of water. Moreover, according to historic case studies, some large landslides are the evolution result of retrogressive landslides. Hence the ability to understand and predict the evolution of retrogressive landslides is crucial for the purpose of hazard mitigation. This paper discusses the phenomenon of a retrogressive landslide by using a model experiment and suggests a reasonably simplified numerical approach for the prediction of rainfall-induced retrogressive landslides. The simplified numerical approach, which combines the finite element method for seepage analysis, the shear strength reduction finite element method, and the analysis criterion for the retrogression and accumulation effect, is presented and used to predict the characteristics of a retrogressive landslide. The results show that this numerical approach is capable of reasonably predicting the characteristics of retrogressive landslides under rainfall infiltration, particularly the magnitude of each landslide, the position of the slip surface, and the development processes of the retrogressive landslide. Therefore, this approach is expected to be a practical method for the mitigation of damage caused by rainfall-induced retrogressive landslides.     

地震危险综合评判的分量分析方法

地震危险性评判，通常需要将多种方法的结果加以综合。为了去除各种方法中可能的重复信息，并对各种方法对危险性评判结论的重要程度进行合理的度量，使综合的结果更加合理，我们引入了分量分析方法。本文首先介绍了分量分析方法的基本原理，其次阐述了该方法在地震危险性综合评判中的应用，最后给出了华北北部中长期地震危险性预测的一个计算实例。     

浅水波模式半拉格朗日方法的并行研究

该文研究的问题是分布式并行计算机消息传递方式下半拉格朗日并行算法, 重点研究二维浅水波并行模式中有关子区域过渡带(HALO)的问题和有关求解赫姆霍兹方程的并行算法。进行了一系列的对比试验, 研究在不同分辨率下模式的并行效率的问题。结果表明:采用分区域并行计算的方法, 可得到较好的并行效率。模式中使用半拉格朗日方法处理平流项是有利的, 在分辨率高时, 可有效地提高计算速度。     

烃降解菌假交替单胞菌N289的全基因组序列及其进化关系

假交替单胞菌属归属于交替假单胞菌科。交替假单胞菌N289菌株分离自南极海冰,我们通过二代测序技术获得了其全基因组序列,组装后获得2条染色体和1条质粒,大小分别是3.2M、636kb和1.8kb。全基因组共包含3,589个ORF,GC含量为40.83%。基因功能分析表明,该菌酶活性高,具有很强的环境适应性。这项研究有助于了解生物多样性、该菌株的进化地位和微生物相互作用关系。     

In situ experiment on retrofit of school buildings by adding sandwich columns to partition brick walls

Many significantly strong earthquakes have occurred over the years in Taiwan, which have caused tremendous damage to primary and middle school buildings; the 921 Chi‐Chi earthquake was particularly devastating. According to statistics, 786 schools (1,958 classrooms) were damaged on September 21, 1999 during this earthquake event. The devastation showed that a lack of seismic performance is a common problem for existing school buildings in Taiwan. Therefore, the retrofit of existing school buildings has become an urgent issue in the prevention of possible damage in the future. The retrofit technique of adding sandwich columns to partition brick walls is proposed in this paper, and the feasibility of the proposed method was verified by in situ pushover tests of two real school buildings, one without and one with retrofit. The experimental and analytical results show that the sandwich column itself contributes significantly to the seismic capacity of the examined school building. Moreover, the analytical results yielded conservative capacity curves when compared with the experimental results. Copyright © 2013 John Wiley & Sons, Ltd.