Impact of typical environments in China’s western mountainous areas on the durability of railway concrete:a review

Purpose–This study aims to analyze the impact mechanism of typical environments in China’s western mountainous areas on the durability of railway concrete and propose measures to improve durability.Design/methodology/approach–With the continuous promotion of infrastructure construction,the focus of China’s railway construction has gradually shifted to the western region.The four typical environments of large temperature differences,strong winds and dryness,high cold and low air pressure unique to the western mountainous areas of China have adverse effects on the durability of typical railway structure concrete(bridges,ballastless tracks and tunnels).This study identified the characteristics of four typical environments in the western mountainous areas of China through on-site research.The impact mechanism of the four typical environments on the durability of concrete in different structural parts of railways has been explored through theoretical analysis and experimental research;Finally,a strategy for improving the durability of railway concrete suitable for the western mountainous areas of China was proposed.Findings–The daily temperature difference in the western mountainous areas of China is more than twice that of the plain region,which will lead to significant temperature deformation and stress in the multi-layered structure of railway ballastless tracks.It will result in cracking.The wind speed in the western plateau region is about 2.5 to 3 times that of the plain region,and the average annual rainfall is only 1/5 of that in the plain region.The drying effect on the surface of casting concrete will significantly accelerate its cracking process,leading to serious durability problems.The environmental temperature in the western mountainous areas of China is generally low,and there are more freeze-thaw cycles,which will increase the risk of freeze-thaw damage to railway concrete.The environmental air pressure in the western plateau region is only 60%of that in the plain region.The moisture inside the concrete is more likely to diffuse into the surrounding environment under the pressure difference,resulting in greater water loss and shrinkage deformation of the concrete in the plateau region.The above four issues will collectively lead to the rapid deterioration of concrete durability in the western plateau region.The corresponding durability improvement suggestions from theoretical research,new technology development and standard system was proposed in this paper.Originality/value–The research can provide the mechanism of durability degradation of railway concrete in the western mountainous areas of China and corresponding improvement strategies.

Poverty Alleviation in the Poor Mountainous Areas of Western China by Supporting Industry: A Case Study of Xundian Hui and Yi Autonomous County in Yunnan Province

Poverty alleviation by supporting industry is a key measure to promote the poverty alleviation of relocated households. Taking Xundian County, the first county in Yunnan Province that has been lifted out of poverty, as an research case, this article analyzes and summarizes the industry-supporting poverty alleviation achievements and successful experience of two typical relocation areas (Shanhou Village and Eyang Village) in Xundian County. Practice has shown that the key to industry-supporting poverty alleviation lies in targetedness to strengthen the participation of poor farmers in industrial development. The interests of poverty alleviation entities should be linked by market mechanism to establish a benign interaction between all parties for win-win situation, thereby effectively guaranteeing the long-term and healthy development of poverty alleviation by supporting industry.

Rural vulnerability,migration,and relocation in mountain areas of Western China:An overview of key issues and policy interventions

Western China features a vast area of mountains and high plateaus where millions of people,including diverse ethnic minority groups,have inhabited for generations.Geographically located in the mountainous,remote,and isolated regions,rural communities are prone to natural hazards and thus become vulnerable to impoverishment.To reduce rural vulnerability,many people residing in mountainous villages opted to out-migrate from their original villages and hometowns while some took in-situ adaptation measures.A host of government-sponsored resettlement programs have been carried out to help rural villagers seek alternative livelihoods elsewhere over the past four decades.To achieve a sustainable future for rural communities in mountainous areas of western China,more effective policies and measures need to be developed and enforced.

The Building of New Countryside in Poverty-stricken Mountainous Area: A case of Hongyan Village,Haizijie Township of Bijie City

The essential drive of building a new countryside lies in scientific and technological innovation. Through expounding the scientific and technological demonstration benefits and roles of new countryside building in poverty-stricken mountainous area,the major problems and hardships of new countryside building in poverty-stricken area are analyzed and the new breakthroughs which should be focused on during the building of a new countryside are put forward. These breakthroughs include transforming the philosophy and approach of rural work; highlighting the construction of rural operation mode and rural socialized service system,and improving the quality of rural labors.

Land Use Regionalization in Poor Counties in Mountainous Areas Based on Targeted Poverty Alleviation

Land use regionalization is a strategic measure for the rational use,management and protection of land resources based on local conditions.Based on the needs of targeted poverty alleviation and rural revitalization strategy and the analysis on the natural and socioeconomic conditions,characteristics of land resources,and the current status of land use in Luquan County,corresponding regionalization indices were selected from four aspects:economic environment conditions,socioeconomic conditions,land resources and land use structure,and poverty alleviation and development level,a scientific and feasible index system for land use regionalization was constructed,and land use in Luquan County was regionalized by using systematic cluster analysis method.The results show that the 16 townships(towns)of Luquan County were divided into four land use regions,poverty alleviation region for development of new town and characteristic industries in the southwest(I),agricultural development and ecological poverty alleviation region in central mountainous area(II),poverty alleviation region for development of characteristic agriculture and tourism towns in eastern plateau mountainous area(III),and poverty alleviation region for development of characteristic industries and protection of land economy in the northern alpine valley area(IV).In addition,suggestions were put forward for the rational use of land in each region.

Study on security and protection of original ecotourism resources in the mountain areas of western Guangxi

Original ecotourism resources mainly refer to natural and human original ecotourism resources, and it＇s of fragility, rarity and irreversibility. As a valuable historic heritage and hnportant tourism resources, it plays a significant role in developing tourism and economy in such areas as the underdeveloped areas, the mountain areas and mimority areas. The tourism resources in the western mountain areas of Guangxi owe ,superiorities and characteristics ＇o their original ecology, Yet, western Guangxi is an ethnic region with fragile karst eco-environment, so it is specialto exploit the tourism resources. The paper defines original eeotourism and analyses the specialties and advantages of the original ecotourism resources as well as thefrailty of the ecotourism resources of the region. The ways of thinking are put forward for safe preservation and sustainable development of the original ecotourism resources, i.e. carrying out measures for the multi-grade protection of heritage resources, setting up a ethnic eco-museum/ ethnic culture eco-park and a gene pool of ethnic cultures, etc.

Impacts of formal credit on rural household income:Evidence from deprived areas in western China

Financial support is a crucial part of China's poverty alleviation effort.Thus,it is vital to understand how formal credit impacts income growth in rural households.In 2012,2015,and 2018,a survey was conducted to obtain a panel dataset of 592 rural households from 6 poverty-stricken counties in western China,including counties in Guizhou,Yunnan,and Shaanxi provinces.We use the data to examine the effect of formal credit on rural household income and the mechanism that underlies this effect.We find that formal credit can significantly increase rural households'income in deprived areas in western China.Furthermore,formal credit promotes the reallocation of household labor from the agricultural sector to the non-agricultural sector and changes rural households'decisions about investment-consumption behavior.These are the drivers of changes in the amount and structure of household income.Further analyses show that formal credit may widen income inequality among rural households in western China's deprived areas.The individual characteristics of rural households,such as different levels of material capital,human capital,and social capital,bring about differences in the effects of formal credit on income growth.This study emphasizes that the implementation of formal credit is an essential strategy for poverty alleviation in underdeveloped areas,but policymakers should not excessively interfere with the financial market.

Primary Deformation Analyses of High Pressure Metamorphic Rock in Western Dabie Mountain Area

In the western Dabie Mountain area, the eclogites have similar compositions and tectonic environment, which could be contrastively researched. Except for the reservation of the early structural deformation inside and outside of the eclogite lens, there is no obvious difference between the characteristics of the foliation and lineation in the eclogite lens from the one in surrounding region. So this paper concludes that the eclogites or blueschists (high pressure metamorphic rocks, i. e. HPM) are basically situated in the original position. The eclogites are mostly superposed by the ductile shear zone and show the feature of structural displacement, but so far we have not discovered any large scale structural zone to uplift eclogite return. Based on the analyses of finite strain measure, petrofabric analysis and TEM image for some minerals such as quartz and garnet, we could efficiently know the deforming characteristics of the eclogite in the prophase and anaphase of the main deforming epoch, and finally determine the forming condition of eclogite according to the strain and the differential stress. This paper puts forward preliminary conclusion that some HPM rocks could be formed by the deep layer embedding and local stress concentration in the process of regional metamorphism.

连片特困地区县域交通扶贫效率测度及影响因素——以滇西边境山区为例

交通扶贫效率测度可为乡村振兴阶段区域交通规划方案制定提供重要的理论依据。以滇西边境山区56个县域四年间交通与经济发展面板数据为样本,构建交通扶贫效率投入产出指标体系,运用DEA模型、Malmquist指数测度滇西边境山区各县交通扶贫效率,并分析其时空分布特征。同时,构建Tobit回归模型,探究县域交通扶贫效率的影响因素。研究表明:滇西边境山区县域交通扶贫效率整体呈逐步增长态势,在乡村振兴阶段仍然有较大提升空间,且交通扶贫综合效率主要受到规模效率的影响;滇西边境山区县域交通扶贫效率大幅提升;依据交通扶贫综合效率的平均值和Malmquist指数值两个维度,滇西边境山区56个县可划分为潜力型、发展型、成熟型及巩固型4种类型,而发展型和成熟型是滇西边境山区交通扶贫效率的主要形态;县域规模、产业结构对交通扶贫效率的提升具有反向抑制作用,就业支持、消费水平、区位优势、投资规模均在不同程度上对滇西边境山区交通扶贫效率产生正向促进作用;各影响因素对不同发展阶段的县域交通扶贫效率在影响强度和作用路径上存在差异。因此,应进一步优化县城交通基础设施空间布局,强化劳动力就业等因素与交通运输发展的“联动效应”,针对不同交通扶贫发展阶段及影响因素短板,采取差异化、合理化发展策略。

Seeking Urbanization Routes for Fragile Human Settlements in Mountainous Areas:A Peculiar Practice for China's Western Region

Based on a deep understanding of the significant strategic role of urbanization during the development of China's western region, this paper sets out to investigate the characteristics of urbanization in the west from the perspectives of population and demographic growth, the level of urbanization, migration, and so forth, and then moves on to examine the major constraints to urbanization and suggest priorities for coordinated development in terms of protection of the ecological environment, poverty elimination, ethnic prosperity, and border security. By summarizing the typical urbanization modes, the paper argues that the healthy urbanization of China's western region should be promoted in a scientific way under the guiding thoughts of "amenable to state intervention, oriented to people's livelihood, suitable for local conditions, and subject to orderly progression."

高地应力蚀变花岗岩隧道大变形特征及成因分析

西部山区某蚀变花岗岩隧道施工过程中,围岩大变形不同程度地造成喷射混凝土剥落、钢架扭曲变形、钢拱架断裂、初支变形侵限以及隧道内坍塌等。为揭示蚀变花岗岩隧道围岩大变形的孕育机理,通过岩石试验、监控量测、数值计算分析和地质综合分析等多种方法,对蚀变花岗岩隧道高地应力及大变形特征、影响因素进行探讨分析。蚀变花岗岩隧道工程区受构造影响强烈,蚀变特征显著,岩体结构疏松,蚀变花岗岩地层为大变形提供充足的物源条件。隧道现场监控量测显示发生大变形的蚀变花岗岩区段与地下水紧密相关,蚀变花岗岩中的伊蒙混石、绿泥石等亲水性矿物成分含量较高,遇水极易崩解,使得岩体抵抗变形的能力大幅降低。结合隧道地质条件和地应力测试,反演分析了隧道初始地应力场,发现蚀变花岗岩隧道以水平构造应力为主,隧道沿线多处于高地应力状态,为大变形的发生提供内动力地质条件。根据隧道开挖过程中发生的支护变形及监控量测分析,复杂地质条件对隧道设计的影响以及施工工艺与支护结构的质量是引起围岩大变形的重要主观因素。

基于联合时序InSAR技术的矿区沉降隐患区识别

针对目前单一InSAR解译技术方法在复杂地表形变解译中精度及可靠性有限的难点,提出了利用PS-InSAR(persist scatterers InSAR)、SBAS-InSAR(small base-line subsets InSAR)这2种时序InSAR技术联合进行山地矿区地面沉降隐患区圈划的方法。以湖北省宜都市松宜矿区为例,基于大样本理论,利用矿区内高精度的PS点形变结果,校正具有高空间覆盖率的SBAS-InSAR处理结果,从而进一步提高地表形变监测精度并增加形变靶区范围圈划的准确度。通过对比使用单一PS-InSAR技术和经过PS-SBAS联合方法处理后得到的典型形变点时序曲线及野外实地调查,验证了解译结果的可靠性。研究表明:联合时序InSAR技术可以提高地表沉降监测精度并增加地表变形靶区范围圈划的准确度,为类似山地矿区的地面沉降隐患监测与分析提供新的技术思路。

辽西低山丘陵区坡面暴雨产流产沙过程及水保效益

基于辽西低山丘陵区二道岭小流域坡面径流和泥沙现场观测,研究暴雨条件下(7·28暴雨)6种不同水土保持措施的坡面产流产沙过程及水土保持效益。结果表明,在暴雨过程中,与裸地相比,耕作措施中的顺垄耕作缩短了初始产流时间,工程措施和林草措施延长了初始产流时间。不同措施的产流产沙过程和雨强变化趋势相似,横垄耕作的径流和含沙量与雨强存在延后现象。在暴雨条件下,以裸地作为对照,林草措施具有良好的减流减沙效果,而农业措施的顺垄耕作则增大了产流产沙作用,加剧了水土流失。

基于GF-7数据的豫西山区地质灾害遥感解译

【目的】查明豫西山区部分区域内崩塌、滑坡等地质灾害的空间分布特征,为地质灾害监测与治理提供科学依据。【方法】主要利用高分七号卫星影像数据,通过构建遥感解译标志、室内初步解译、野外核查验证、内外业综合解译、编制解译成果图件等步骤开展遥感解译工作。此外,还对比分析了多类型多时相的遥感影像,并结合研究区的地形地貌等地质资料,进一步提高了地质灾害的可解译性。【结果】在此次地质灾害遥感解译中,实际正确识别了15处滑坡、6处崩塌,解译正确率达91.3%。遥感解译的精度和效率较高,取得了较好的成果。【结论】本研究提出的利用高分七号遥感卫星数据开展地质灾害遥感解译思路及方法,在该地区所进行的地质灾害遥感解译工作中表现出显著优势,具有较强的实用性和可行性,能够为其他地质灾害遥感解译工作提供有力的参考和指导。

Topographical relief characteristics and its impact on population and economy:A case study of the mountainous area in western Henan,China

Topographical relief is a key factor that limits population distribution and economic development in mountainous areas. The limitation is especially apparent in the mountain-plain transition zone. Taking the transition zone between the Qinling Mountains and the North China Plain(i.e. the mountainous area in western Henan Province) as an example and based on the 200-m resolution DEM data, we used the mean change-point analysis to determine the optimal statistical unit for topographical relief, and thereafter extracted the relief degree. Taking the 1:100,000 land use data, township population and county-level industrial data, population and economic spatial models were constructed, and 200-m resolution grid population and economic density maps were generated. Afterwards, statistical analysis was carried out to quantitatively reveal the impact of topographical relief on population and economy. In addition, the impacts of other topographical factors were discussed. The results showed the following.(1) The relief degree in western Henan is generally low, where 58.6% of the regional topography does not exceed half the height of a reference mountain(relative elevation ≤250 m). Spatially, the relief degree is high in the west while low in the east, and high in the middle while low in the north and south. There is a positive correlation between relief degree and elevation, and a much stronger correlation between relief degree and slope.(2) The linear fitting degree between the population and economic validation data and the corresponding simulation data are 0.943 and 0.909, respectively, indicating that the spatialized results can reflect the actual population and economic distribution.(3) The impact of topographical relief on population and economy was stronger than that of other topographical factors. The relief degree showed a good logarithmic fit relationship with population density(0.911) and economic density(0.874). Specifically, 88.65% of the population lives in areas where the topographical relief is ≤0.5 and 88.03% of the gross regional product was from areas where the relief is ≤0.3. Compared with the population distribution, the economic development showed an obvious agglomeration trend towards low relief areas.

Comprehensive Evaluation of Farm Household Livelihood Assets in a Western Mountainous Area of China: A Case Study in Zunyi City

As the foundation of farm household structure,livelihood asset status is the basis for farmers to gain opportunities,adopt livelihood strategies,resist livelihood risk,and engage in positive livelihood achievements.Quantifying farm household assets identifies future development trends that are fundamentally necessary to predict farm household vulnerability and strategy,as well as understanding farmers’current living situations.Using Zunyi City in China’s western mountainous area as a case study,we conducted stratified sampling and participatory rural investigation appraisal to collect data on the attributes of farm households’livelihood assets and livelihood strategies to establish an index evaluation system and enable evaluation and analysis of farm households with different livelihood strategies.Our research indicates that due to structural differences,total livelihood assets of farm households with different livelihood strategies are similar.Rural households have an abundance of natural and material assets and deficiencies in human,financial and social assets.Non-rural households and part-time households are abundant in human,financial and social assets and deficient in natural and material assets.

西部民族地区“两山”转化指数测度及对共同富裕影响效应研究

文章从“绿水青山”和“金山银山”两个维度测度了“两山”转化指数,从发展性、共享性和可持续性三个维度测度了共同富裕发展水平,利用2011—2020年西部民族地区省域面板数据实证考察了“两山”转化对共同富裕的影响效应和作用机制。研究发现:在我国西部民族地区,“两山”转化显著推动了共同富裕的实现,且产业结构升级是“两山”转化推动共同富裕实现的重要传导机制,“两山”转化通过促进产业结构高级化和产业整体结构优化加快共同富裕发展;“两山”转化与共同富裕发展间的正向关系存在显著的异质性,在“绿水青山”程度较高、第三产业占比较高、科技发展水平较高以及政府转移支付较高的情境下推动作用更明显。

DEBRIS FLOW DISASTER AND ITS MITIGATION COUNTERMEASURES IN THE CONSTRUCTION OF THE MOUNTAIN AREAS IN THE WESTERN CHINA

The economy and construction of cities/towns in the mountain areas will grow rapidly along with deepening of the western development program, during which debris flow disaster will be more serious. How to solve this problem and mitigate the debris flow disaster is an important task. In this paper, the distribution, harm and developing tendency of debris flow were analyzed. After discussing prevention projects, rebuilding and expanding of old cities/towns and traffic construction that will meet debris flow problem, integrative mitigation countermeasures, such as controlling debris flow by civil engineering, improving drainage area environment by biologic project, forecast of risk zones and disaster situation, were put forward.

鄂西山区日本落叶松人工林全林整体模型研究与应用

为解决林分各测树因子及其生长模型之间的相容性问题,采用非线性度量误差联立方程组法建立鄂西山区日本落叶松人工林全林整体模型。研究结果表明,非线性度量误差联立方程组方法,能保证模型的相容性与无偏性;各林分因子的平均相对误差和相对均方误差均在6.5%以下,模型参数稳定性及预测精度均较高;建立的全林整体模型可用于不同初始条件的日本落叶松人工林林分生长收获预估、定量间伐作业设计以及林分密度控制图绘制。相关研究结果可为研究区日本落叶松人工林高效可持续经营提供科学参考。

西部山区泥石流灾害下建筑物破坏特征与破坏等级划分

近年来我国西部山区泥石流灾害频发,严重威胁当地居民的生命财产安全,其中,建筑物的破坏是造成各类损失的重要原因。正确认识泥石流的致灾机理和泥石流灾害下建筑的破坏特征不仅是正确评价泥石流灾害风险的基础,也是科学构建泥石流下房屋建筑易损性模型的依据。基于文献查阅、新闻资料和现场调研,首先对西部山区泥石流灾害主要特点进行了归纳阐述,其次梳理了近年来发生泥石流灾害中建筑物的破坏特征,最后结合泥石流的动力学特性和建筑结构情况剖析了建筑结构的受损机理。基于建筑物的空间分布与泥石流强度的时空耦合变化特征,对泥石流强度表征方式给出方向性建议;基于建筑的受损机理,参考地震作用下建筑的破坏等级划分标准,初步提出了泥石流下建筑物破坏等级划分方式,旨在为防灾减灾工作提供一定参考。