持续推进桥梁科技创新不断增强企业核心竞争力

中铁大桥局集团有限公司的前身是铁道部大桥工程局，是为兴建武汉长江大桥于1953年成立的我国唯一一家集桥梁科学研究、勘测设计、营建施工、机械制造“四位一体”的大型专业桥梁企业。半个多世纪以来，大桥局坚持不懈推动桥梁科技创新，迄今在国内外设计建造桥梁达600余座，其中一大批桥梁接近或达到世界先进水平。     

鄂东北大别杂岩中混合岩形成的动力学机制

本文针对中小位移量伸缩缝构造进行设计研究，提出了一种常温固化型桥梁伸缩缝。经过对伸缩量Δ２０ｃｍ，Δ＝４０ｃｍ的多座桥梁的实验应用表明，这是一种适用于中小位移量桥梁中性能良好的伸缩缝，施工简便。其桥缝具体结构为，在两侧拍击区采用钢纤维混凝土增，缝内用高分子聚合物与一定比例的水泥及掺合物拌和均匀，经一段时间与桥面和加固铺装层固化成具有较高弹性和一定强度的整体式桥梁伸缩缝。其效果良好，供应用参考。     

孟凡超大师主要业绩

孟凡超大师简介 孟凡超，男，汉族，1959年12月出生，四川人，中共党员。1982年7月毕业于重庆建筑工程学院桥梁与隧道专业。历任中交公路规划设计院（原交通部公路规划设计院）桥梁室副主任、主任、副院长，教授级高级工程师。兼任中国土木工程学会桥梁及结构工程分会副理事长，中国公路学会桥梁和结构工程分会副理事长，中国土木工程学会混凝土及预应力混凝土分会副理事长，（（土木工程学报》编委会委员，中国国际工程咨询公司专家委员会专家，中国工程建设标准化协会第四届结构设计基础委员会委员，国际桥梁协会委员。1998年获“中国公路学会百名优秀工程师”荣誉称号，2001年获“中国路桥（集团）总公司劳动模范”荣誉称号，2001年度获国务院政府特殊津贴，2004年获首批“新世纪百千万人才工程国家级人选”称号。2006年被评为全国工程勘察设计大师。[编者按]     

双曲拱桥的验算与病害分析

以路里桥这一双曲拱桥为对象，通过对其质量现状的检测和对主拱圈的验算，对桥梁质量现状进行评价和病害原因分析。     

南阳车站道岔更换引发的同向曲线改造

在对焦柳线南阳车站南岔区2#和4#两组渡线道岔由9号更换为12号并引起相邻道岔向外平移，且相应地对南阳市二胶化工厂专用线的两个同向曲线进行改造时，以桥梁和桥梁所在的曲线作为不动控制点，相应扭转两组同向曲线的公切线，这为类似同向曲线改造提供了一种设计思路和方法。     

地下水开采对桥梁结构影响的离心模型试验研究

地下水开采是导致地面不均匀沉降的重要因素之一,而地面不均匀沉降又会对桥梁结构造成较大的危害。通过离心模型试验研究了离心场中地基抽水对桥梁结构物的影响。在自主研制的离心场中地基抽水对结构物影响的模拟和测量系统基础上,测量了抽水过程中粉土地基中沉降的变化以及桥梁结构的变形分布规律,探讨了地面不均匀沉降对刚性桥梁、简支桥梁以及简支连续桥梁的影响规律。试验结果表明,水井抽水的初期非稳定渗流期是桥梁变形发展最快的阶段;减小桥垮长度以及桥面桥墩改用铰连接都可以使得桥面轴向应变减小;地基的水平位移会给刚性桥梁中部带来较大的变形     

北京地铁工程邻近桥桩施工风险评估及控制对策探讨

探讨了北京地铁工程邻近桥梁施工风险等级划分应考虑的因素和风险等级划分方法,建议以桥基与地铁工程开挖影响破裂面的位置关系和桥基与地铁工程的水平距离作为主要依据,确定桥梁邻近等级。在此基础上,综合考虑桥梁现状质量,确定邻近桥梁的施工风险等级,并对不同的风险等级给出了相应的邻近桥梁基础加固保护对策,从而形成了对邻近桥梁的控制与保护技术程序,最后通过一个工程实例介绍了对邻近桥桩的评估及处理。     

桥梁伸缩缝处跳车的成因分析及防治措施

结合安徽省部分桥梁伸缩缝处跳车防治设计、施工实践,对桥梁伸缩装置损坏的成因进行了较系统的分析,并提出了防治桥梁伸缩缝处跳车的基本措施,供桥梁伸缩缝设计、施工、养护工作参考.     

对公路桥梁高墩台施工技术的行业探讨

新时期,我国公路桥梁建设的速度发展迅速,桥梁建设正在发挥着重要的交通作用,对经济和社会起着提升和加速的作用,目前,随着公路桥梁技术的不断进步,公路桥梁建设质量得到进一步提升,各种各样的公路桥梁不断出现,并被有效地应用到交通网络的连接和构建之中。公路桥梁出现了跨径变长、墩身增高的趋势,这就需要公路桥梁建设技术人员对此加以关注,通过行业内技术的研讨,推进公路桥梁施工技术的提高,确保公路桥梁的施工质量。公路桥梁墩台是桥梁上部负荷承载的主要结构,同时还承载着风力、流水等外力的影响,也存在着冰压力和外力撞击的可能,种种因素都需要我们加强对公路桥梁墩台的重视,以严格的技术、高品质的公路桥梁施工确保公路桥梁墩台对各种负荷、外力和侵害的有效抵御。公路桥梁高墩台施工技术是公路桥梁高墩台施工质量的有效保障,应该立足公路桥梁墩台的设计和施工的实际工作,开展对公路桥梁墩台施工技术的研讨和学习,切实掌握决定公路桥梁高墩台施工质量的钢筋安装、混凝土运输、混凝土浇筑、混凝土养护、安全管理等技术环节,在合理运用液压滑膜技术和翻模施工技术的基础上提升公路桥梁高墩台质量,实现为具体的路桥梁高墩台施工提供技术梳理和关键环节提示的作用。     

桥梁基础的压气沉箱施工法

本文简要介绍了一种特殊的施工方法——压气沉箱工法在桥梁基础设计与施工上的基本概念，并结合实例说明了它的主要的特点。压气沉箱工法在日本广泛应用于跨河跨海桥梁建设上，但在我国尚无实例。     

径潮动力对长江河口滞流点的影响

为研究三峡蓄水后滞流点的时空变化规律,应用ECOMSED模型模拟长江河口在不同径流、潮流作用下的水流动态过程。结果表明:北支大洪水期下移幅度大,涨潮动力强劲,随潮流变化大;南侧变化幅度整体较北支小,随径流的变化幅度自大至小依次为北港、南槽、北槽;随潮流的变化幅度自大至小依次为南槽、北港、北槽。滞流点随径、潮条件变化时,受地形影响明显,三峡蓄水后,径流变化范围缩小,引起不同地貌单元滞流点范围不同程度的缩小,可据此认为,与滞流点位置一致的最大浑浊带范围呈现减小的趋势,由此可能引起最大浑浊带和地貌调整。     

Spatial patterns of Holocene glacier advance and retreat in Central Asia

Glaciers in the southern Himalayas advanced in the early Holocene despite an increase in incoming summer solar insolation at the top of the atmosphere. These glacier advances are in contrast to the smaller alpine glaciers in the western and northern regions of Central Asia. Two different glacier mass-balance models are used to reconcile this Holocene glacier history with climate by quantifying the change in equilibrium-line altitudes (ELA) for simulated changes in Holocene climate. Both ELA models clearly show that the lowering of ELAs in the southern Himalayas is largely due to a decrease in summer temperatures, and that an increase in monsoonal precipitation accounts for less than 30% of the total ELA changes. The decrease in summer temperatures is a dynamic response to the changes in solar insolation, resulting in both a decrease in incoming shortwave radiation at the surface due to an increase in cloudiness and an increase in evaporative cooling. In the western and northern zones of Central Asia, both ELA models show a rise in ELAs in response to a general increase in summer temperatures. This increase in temperatures in the more northern regions is a direct radiative response to the increase in summer solar insolation.     

Neoliberalism and water reforms in western India: Commercialization, self-sufficiency, and regulatory bodies

This paper deals with the changes brought about by the ‘reforms’ in water currently under way in many parts of the world. Three particular reforms in the state of Maharashtra in western India are discussed - the commercialization of a parastatal body, the concept of self-sufficiency as it plays out in the context of urban local bodies, and the working of the regulatory body in water. The analysis of these reforms shows how, in common with neoliberal projects elsewhere, changes in institutional practices are resulting in changes in subjectivities, foreclosing alternatives, and leading to attempts to ‘depoliticize’ the water arena. At the same time, there are differences between the regulatory experience of Maharashtra and regulation in other locales, which offers insights into how neoliberalism works in a context where water reforms have emerged relatively late.     

Temporal–spatial variability of soil fertility in karst region: a case study of Xiaojiang watershed Yunnan

By sampling in the field and analyzing the soil samples in the laboratory in 1982 and 2005 the soil fertility data were obtained. Through application of geo-statistics combined with GIS, the temporal–spatial variability of the pH, organic matter, total nitrogen, total phosphorus and total potassium in soil of Xiaojiang watershed from 1982 to 2005 were analyzed. Results showed that: (1) the pH value and total potassium in soil showed an increasing trend, but the organic matter, total nitrogen and the total phosphorus in soil declined in the past 20 years in Xiaojiang watershed, (2) the parameters fitted by semivariogram models for fertility indices changed significantly in the past 20 years and (3) the result estimated by ordinary Kriging indicated the spatial pattern of the soil fertility indices changed significantly in the past 20 years. The soil pH increased in the east and southeast, but decreased in the middle of the watershed. The organic content of the soil matter decreased in the east, southeast and southwest, but increased in the northeast and middle of the watershed. The total nitrogen content of the soil decreased in the east, but increased in the middle of watershed. The total phosphorus content of the soil decreased in the whole watershed. The total potassium content of the soil increased in the southwest and southeast, but decreased in the middle of the watershed and (4) the change of land use and soil management measures was the main driving force of variability of soil properties.     

鄂尔多斯盆地地下水中氚的演化及其年龄

通过总结20世纪60年代以后不同时期大气降雨氚的组成,根据衰变定律,描述了氚在不同时期形成的地下水中的演化轨迹;通过比较不同时期大气降雨氚的组成和所形成的地下水中氚的演化,得出地下水中氚的衰减速度比大气降雨中氚的更新速度慢这一结论;根据鄂尔多斯盆地地下水中氚的组成,解释了鄂尔多斯盆地地下水的形成年龄。     

Distribution Characteristics of Sulfur and the Main Harmful Trace Elements in China's Coal

To promote the rational development and use of clean coal resources in China,data on the regional and age distribution of sulfur,arsenic and other harmful elements in Chinese coal was broadly collected,tested for content,and analyzed.Coal in northwestern China is characterized by low to extremely low levels of sulfur;the coal of the Taiyuan Formation in northern China mainly has high-sulfur content;that of the Shanxi Formation is mainly characterized by low sulfur coal;and the Late Permian coal in southern China has overall higher sulfur content;other regions have low sulfur coal.The average content of harmful trace elements in the bulk of China's coal is similar to the corresponding content in the coal of the North America and the rest of the world,whereas the content of various elements(Hg,Sb and Se)is different in magnitude to the corresponding percentage in the crust.The average content of the elements Cr,Se,Co,Be,U,Br in Late Permian coal in S China ranks first in the country whereas the average content of Hg and Cl in the coals of Late Carboniferous to Early Permian age in N China are the highest.The average content of Mn in Early and Middle Jurassic coal is higher in NW China.The high content of harmful elements in some coal should cause particular concern both in the development and utilization of coal.     

Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau: Current status and transfer mechanisms

This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau. The study surveyed the average abundance of microplastics in sediments. The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22–2643.65 items/kg DW and 0–60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin. The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world. Like microplastics in other lakes of the world, those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA, PET, PE, and PP and are primarily in the shape of fibers and fragments. The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities, and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains. Furthermore, the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments. This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.©2022 China Geology Editorial Office.     

干旱区绿洲城市城镇化发展状况及协调性浅析——以吐鲁番地区为例

城镇化是一个国家或地区经济发展的必经途径,同时也是衡量某地区经济发展水平的重要标志之一。城镇化进程不仅关系到区域人口、经济和环境的可持续发展,还关系到区域平衡与区域生产效率,以致关系到区域的综合竞争力。利用2001—2011年吐鲁番地区人口、经济、社会和生态方面的相关数据,剖析吐鲁番地区城镇化系统,选出并构建吐鲁番地区人口、经济、社会和生态4个城镇化系统的6个评价指标体系,对指标进行定量分析;计算城镇化4个系统以及城镇化发展水平的综合评价指数及其各系统的协调度,根据各子系统评价指数建立数学模型,分析吐鲁番地区城镇化驱动因子以及制约该地区城镇化进程的影响因素;并推算出吐鲁番地区城镇化的变化和发展趋势。     

水及溶质在有大孔隙土壤中运移的研究(Ⅰ):田间实验

通过田间原状土和回填土渗透比较试验,揭示了大孔隙对水及溶质在土壤中运移的影响。通过回填土和原状土中含水率实验结果比较分析,指出回填土和原状土含水率的变化呈现不同分布特征。而对回填土和原状土中溶质浓度实验结果分析比较,发现回填土中水分运动和溶质运移的速度显著低于原状土,回填土和原状土都有位置深的检测点先于其上面的检测点出现溴离子的现象,回填土中硝酸根离子的浓度远低于其在原状土相应深度的浓度。     

甘肃黑河中下游影响绿洲植被发育的某些因素

黑河下游额济纳绿洲区和中下游沿黑河干流河床附近的潜水位埋深较浅,是维系地表植被生长的重要因素。中游高台附近潜水位存在每年双峰值的变化,较之下游额济纳绿洲潜水位每年单峰值的变化更有利于植被的生长。在包气带剖面中,同一时刻水土势、含水量、含盐量随深度的变化趋势基本相同。采样点包气带土壤中易溶离子含量相对较低,全盐量小于5%,中游采样点土壤中以HCO3-为主,下游以SO42-为主,由SO42-、Cl-和Na+、Ca2+组成的盐类构成了包气带土壤中的主要盐分。土壤中易溶离子含量自地表至潜水面之间随深度总体上呈减小趋势。植被的根系分布对包气带土壤含水量、水土势和易溶离子含量随深度的分布有着重要的影响,在植物根系发育带的土壤中含水量、水土势和易溶离子含量升高。