滑坡监测预警国内外研究现状及评述

本文从降雨临界值研究、监测技术方法、区域性监测预警系统三个方面对滑坡监测预警的国内外研究现状进行了回顾和总结。首先归纳了国内外28个国家或地区的滑坡降雨临界值及统计方法,三个模型——日降雨量模型、前期降雨量模型和前期土体含水状态模型,基本概括了当前降雨诱发滑坡临界值的确定方法;但由于降雨入渗触发滑坡的复杂性,不同机理的滑坡"需要"不同的降雨临界值;目前的研究趋势是对雨量雨强雨时—土体渗流场动态变化—土体抗剪强度变化的耦合关系进行研究。按监测对象的不同,滑坡监测可分为四大类,即位移监测、物理场监测、地下水监测和外部诱发因素监测;按监测手段的不同,则可分为人工监测、简易监测、专业监测三大类;目前国内外在滑坡监测技术、方法、手段上并无太大差距,专业仪器已成为常规设备,只是由于价格因素得不到普及;一些新技术如InSAR、三维激光扫描等能很快应用到滑坡监测领域;监测数据的采集和传输也都实现了自动化和远程化;监测和预警系统有向Web—GIS发展的趋势。利用一个地区的滑坡易发区划或危险区划,结合降雨临界值,可以设定不同的预警级别,在区内布设一定数量的雨量站,监测雨量加上预报雨量,就可进行滑坡预警预报,国内外的区域性降雨型滑坡监测预警大体都是这个思路和做法,该方法在对公众进行警示方面起到了良好效果,但由于预警的范围太大,在具体的单点防治上,难以做到有效。我国在近10年开展了大量的监测预警工作,并取得了丰硕的成果,但根据统计数据,其成功预警率却并不理想,这一方面表现在成功预警实例中专业预警所占比例过低,另一方面同时表现在发生的大量的地质灾害在已有的预警点之外。制约目前工作有效性的主要问题是滑坡隐患点的排查和识别问题,因为只有识别出了隐患点才能进行下一步的监测和预警,它是一切工作的基础。而解决这一问题的重要途径是分析区域上的滑坡发育规律,找到有效的隐患点识别技术方法,以及引进风险管理的概念,进行监测资源的合理分配和有效预警。     

深基坑监测方法浅析

随着高层及超高层建(构)筑物的增多,深基坑也越来越多,为了保证深基坑的施工安全,防止深基坑开挖影响周围建筑物、道路、设施及地下管线的安全,在基坑施工出现异常情况时及时反馈,并采取必要的工程应急措施,按照规范要求必须进行基坑监测。本文结合工程实例,提出了深基坑监测的基本要求和施测方法,确保施工质量及基坑周边的安全。     

忻州地下水动态监测方法探讨

地下水动态监测工作是水利建设和地下水开发利用的一项基础工作.本文根据多年来的工作实践,对忻州地下水监测工作的各个方面进行了叙述和总结.     

辽宁省水质监测工作回顾与展望

通过对辽宁省水质监测工作的回顾和水质监测工作现状评价,分析评价了水资源质量,以及开展水质监测的必备条件,并就水质监测工作发展方向提出了初浅的看法.     

黄土坡面径流侵蚀产沙动力过程模拟与研究

通过室内模拟冲刷试验系统研究了3°~30°坡度范围内坡面径流的侵蚀动力及产沙特征,分析了坡面径流能耗与径流侵蚀产沙之间的关系。结果表明,坡面径流平均流速随坡度和流量的增加而增大,流速与坡度和流量之间存在指数函数关系,坡度对流速的影响大于流量。在3°~21°坡度范围内,坡面径流单宽能耗随坡度的增加而增加,当坡度超过21°时,径流能耗随坡度的增加而降低。坡度对侵蚀产沙的影响也有类似的现象,在3°~21°坡度范围内,坡面径流平均单宽输沙率随坡度的增加而增大,当坡度达到临界极值21°和24°后,坡面径流平均输沙率随坡度增加而减小;在整个试验坡度范围内,径流平均单宽输沙率随流量的增大而增大;流量对坡面径流平均单宽输沙率的影响大于坡度。坡面径流平均单宽输沙率和单宽径流能耗之间存在明显的线性关系,其临界单宽径流能耗随坡度的增加而增加,土壤可蚀性参数随坡度的变化在10.368~30.366的范围变化,试验的土壤可蚀性的平均值为14.61。     

陕西省地下水管理监测30年回顾与展望

在回顾陕西省地下水管理监测工作30年发展历程、总结“十五”发展成就和分析存在问题基础上,提出了“十一五”总体指导思想和发展目标,指出要不断加强水资源管理监测基础工作,依法履行地下水管理监测工作职能,为确保地下水资源可持续利用、保护水环境而不懈努力。     

苏锡常地区地面沉降监测方法体系建设

运用精密水准测量、自动化监测、GPS测量、In SAR监测、光纤监测等多种技术手段开展了苏锡常地区地面沉降监测工作。随着地面沉降时空动态的不断演变,不同监测技术手段的应用效果出现较大差异,需要探讨动态变化的地面沉降条件下不同监测方法的适用性,并以此建立更为高效、可靠的监测方法体系。笔者在总结以往工作基础上,对所使用的方法进行了梳理和总结,分析了不同方法的优缺点及其适用性,提出应根据工作程度实施各种监测技术方法搭配及集成应用的监测方法体系的结论。     

滑坡应急变形监测方法的探讨

以通川区石龙溪滑坡应急变形监测为例,说明在城市中滑坡应急变形监测常用的一些方法。通过对这些方法的综合分析,探索出一种最切合实际的技术方法,以适应城市快速发展中各种地质灾害点的应急监测需要。     

高速公路隧道施工放射性监测方法初探

重点介绍了隧道工程放射性监测所采用的标准、监测对象、仪器、方法和评价指标的计算,以及对异常放射性的处理措施,并对后续相关工作的开展提出建议。     

北京市地面沉降监测系统及技术方法

北京市地面沉降监测系统由地面沉降监测网、地面沉降专门监测网、GPS监测网、地下水位动态监测网及InSAR监测网构成.结合北京市近年来地面沉降监测工作,分析总结了标孔监测和质量控制方法,提出了将GPS监测分为控制网和监测网两级监测的方法,提高了监测精度,尝试采用InSAR测方法对部分重要轨道交通进行地面沉降专项监测研究.对地面沉降监测网络建设及优化有一定的指导意义.     

Review and Prospect of the Study on Soil Wind Erosion Process

Soil wind erosion processes include mechanical process and dynamic changes of the factors affecting soil wind erosion, as well as the corresponding changes of wind erosion rate. The former is rich in experimental and theoretical researches that have clearly defined the process of particle starting, transporting and settling. The latter focuses on the dynamic changes of various wind erosion factors and the response of soil wind erosion rate to the change of the factors, of which systematic research of which is very limited. The difficulties in research of soil wind erosion process include: ①Dynamic parameterization of wind erosion factors; ②Observation and quantitative expression of the dynamic changes of wind erosion factors; ③Scaling problem of wind erosion process; ④Prediction ability of wind erosion models. At present, it is urgent to carry out the following work on soil wind erosion. The first is to establish standard wind erosion observation field in typical regions to obtain continuous and complete data of wind erosion in the field; the second is to study the saturation path of wind sand flow to solve scale problem; and the third is to construct a wind erosion model with solid theoretical foundation and fully consider both mechanical process of soil wind erosion and dynamic changes of the factors.     

Wind Tunnel Experiment of Anti-erosion Efficiency on the Sand Beds Coverd by Different Shapes of Roughness-Elementes

In order to study the relationship between the shapes of roughness-elements on sand beds and the surface sand activity inhibition, we chose six shapes of elements including spherical, triangular pyramid shape, cylindrical, square shape, pie and hemispherical shape by hand with equal quality kept. We carried out the experiment with the 10% coverage on the wind tunnel. The results revealed that ① the erosion and anti-erosion rate of spherical, triangular pyramid shape, cylindrical and square roughness-elements were better than the pie and hemispherical on the non-sand wind; ② On the sand-driving wind conditions, spherical, triangular, cylindrical covered beds became erosion to erosion-deposition with the increase of wind speed, and the erosion rate was increased with the wind speed. When the wind speed was more than 10 m/s, the sand-beds showed a strong erosion, and the pie and hemispherical elements’ resistance function were weakest; ③ No matter the non-sand wind or sand wind, the erosion rate was affected by the elements’ aspect ratio, height and spacing. The slender elements with a prominent upper edge were clearly superior to broad rounded elements.     

Advances in Researches of the Effects of Grassland Vegetation on Soil Erosion in Loess Plateau

Soil erosion is a serious global environmental problem which limits the survival and development of human beings. In our country, due to the special physical geography and socio-economic conditions, soil erosion intensity is great, which is particularly prominent in Loess Plateau region. Therefore, preventing and controlling soil erosion, as well as reducing soil erosion in Loess Plateau have become the key to solving environmental problems in the region. Soil erosion on Loess Plateau is serious, and grassland vegetation has good effects on soil and water conservation, which can improve ecological environment well. After the implementation of the project about returning farmland to grassland on Loess Plateau, the ecological benefits mainly focused on soil and water conservation benefits, soil improvement benefits, water conservation benefits and species diversity benefits, etc. Grassland vegetation has an irreplaceable role in the construction of the ecological environment on Loess Plateau. Therefore, the role of grassland in preventing soil erosion has received more and more attention. Scholars have done lots of research involved in the relationship between grassland coverage and soil erosion, impacts of grassland on hydrodynamic parameters, effects of grassland on soil properties, reduction effects of grassland on runoff and sediment, and soil erosion process on grassland slope. However, there is little research on erosion effect induced by grassland cover. This paper mainly pointed out the following questions: First, grassland cover is influenced by many factors, but the relationship with soil erosion from the dynamic mechanism is rarely discussed; Second, there is no well-developed theory of overland flow erosion at present, which limits the study of hydrodynamic parameters on grassland slope; Third, establishment of mathematical model between grassland cover and soil resistance can accelerate the quantitative analysis of grassland influence on erosion; Fourth, comprehensive analysis of influencing factors on water reduction and sediment reduction effect on grassland are insufficient; Fifth, there are not many mechanisms to analyze the erosion process of grassland slope by using the hydrodynamic characteristics of slope; sixth, research results on grassland-induced erosion are mainly focused on leading to soil dry layer and we should continue to strengthen in the future. This paper summarized the previous results, and supplemented some studies about erosion caused by grassland, then pointed out the existing problems in current research and the areas that need to be strengthened in the future, aiming at reducing soil erosion on the Loess Plateau.     

Review of Methodologies for Offshore Wind Resource Observation and Assessment

Observation and assessment of wind resources is a prerequisite for wind farm construction. Due to the investment cost of offshore wind farm is very expensive, more accurate assessment of wind resources is needed to reduce their investment risks. From traditional field observation to multi-platform remote sensing and from ordinary mathematical statistics to coupled numerical model simulation, abundant offshore wind data and evolving assessment methods make the results of offshore wind resource assessment more and more reliable. Poor station observations and rich remote sensing data are distinct characteristics of offshore wind data. Technology integration of applying multi-scale coupled models to assimilate multi-source remote sensing and station data is a mainstream development direction of offshore wind resource assessment methods. The wind resource assessment for offshore wind farm should focus on data quality and method selections of data interpolation, wind speed calculation of return period and wind energy parameters adjusted for a long term condition because these factors can significantly affect the operating efficiency of future wind farm.     

Progresses and Prospects of the Research on Soil Erosion in Karst Area of Southwest China*

The karst area of Southwest China is suffering from serious ecological and environmental problems due to soil erosion while the research on soil erosion is not sufficient. Primary achievement was systematically reviewed in this paper in three aspects: erosion characteristics, current researches about erosion on different spatial scales, and key scientific problems. Based on the review, the authors figured out the shortcomings of the existing studies and pointed out the directions on erosion study in southwest China karst region. The results showed that: ① Due to the existence of a dual structure in karst environment including ground and underground erosion, the process of runoff and sediment production on slope scale and confluence and sediment transportation processes on catchment scale were more complex under the unique geological and hydrological backgrounds; ② At present, most researches about erosion mechanism in karst area focus on slope scale and some achievements on quantitative evaluation of erosion factors have been made. Continuous data with high quality about relationship between water and sediment on catchment scale is limited. When data is scarce, river sediment data can be used as an effective way to study soil erosion intensity and spatial-temporal variation in karst area; ③ It is more reasonable to use 50 t/(km²·a) as the grading standard of soil loss tolerance than the previous grading standard of soil erosion intensity. Given the complex relationship between rocky desertification and soil erosion, more quantitative studies about the effects of rocky desertification on soil erosion are still necessary. There are different viewpoints on soil leakage definitions, leakage mechanism and leakage ratios, and new breakthroughs could be achieved by combining different methods and matching multi-scales. In conclusion, in order to further reveal soil erosion laws and establish and revise available regional soil erosion forecasting models for Southwest China karst areas, synchronous test and monitoring on slope, watershed, and channel spatial scales are urgently needed. The results can provide theoretical and technical support for promoting soil and water conservation work for the karst area of Southwest China.     

An Overview of Measurement and Calculation Methods on the Land Surface Temperature on Alpine Mountainous Cold Regions

Land surface temperature on alpine mountainous cold regions, which is one of basic parameters of the regional hydrological and meteorological conditions, directly affects glacial recession, snow melt, distribution and freezing thawing process of permafrost, evapotranspiration, vegetation growth, and various underlying surface change process, and then changes the regional hydrological and ecological environment, becomes the important parameter of the research on land surface process and the study of eco-hydrological process. This paper tried to provide an overview of research on land surface temperature, and to introduce its influence factors and the ways to obtain land surface temperature data in high mountainous cold region. Relative to low elevation plain, the land surface temperature was significantly affected by local altitude, terrain and plant cover. There were some methods to obtain land surface temperature, such as measurement in situ, retrieval based on remote sensing and calculation by land surface process models, but there were some limitations while used on alpine mountainous cold regions. Land surface temperature data from meteorological stations were only about level bare ground, and the influence of terrain or vegetable cover was not considered. Therefore, the data could not represent the information of region scale on mountainous area. Land surface temperature retrieval from remote sensing data, because of calculation theory, ground observation verification and spatiotemporal resolution, made it difficult to fulfill research on hydrology, land surface process and eco-hydrological process in alpine mountainous area. Land surface process models estimated land surface temperature in the experimental sites with high accuracy, but reduced the accuracy while upscale to the region scale on the mountainous cold area, because of the error from input control meteorological, soil and plant variables, and the error of ground observation site verification. The future research on land surface temperature on alpine mountainous cold regions should strengthen field observations and improve data accuracy, to build a physical land surface temperature estimation method with topographic and vegetation parameters, and to contribute to research on land-atmosphere-water process in alpine mountainous regions.     

田块尺度作物辐射温度获取方法对比研究

热像仪的优势在于可以获得组分辐射温度,常用于地面温度同步测量实验中,其数据与植被覆盖度联合还可以得到作物田块尺度的平均辐射温度。以黑河流域进行的星—机—地遥感综合观测试验加密观测——盈科绿洲玉米地的热像仪和手持式红外辐射计温度测量数据为基础对不同采样方式获得的地面辐射温度进行对比。对于热像仪数据:①采用阈值法对热像仪影像中的玉米和土壤背景两组分进行分离,获得了各自辐射温度的平均值;②利用LAB彩色变换法处理同步拍摄的真彩色照片,获得每块玉米样地的植被覆盖度;③最终结合组分温度和植被覆盖度求得地块平均的辐射温度。经过实验对比发现,由热红外图像计算获得的地面平均辐射温度与手持式红外辐射计垂直垄或顺垄条带采样获得的地面平均辐射温度差值较小,基本在±1℃以内,而3种测量方式的最大值、最小值相差较多。还模拟了几种常见尺度下利用手持式红外辐射计进行随机采样时,其采样平均值以不同的置信度处于真实温度±0.5℃之间所对应的采样次数。分析表明,基于点测量的采样方案难以仅利用1~2台手持式红外辐射计实现对田块或更大尺度平均辐射温度的准确测量,高时空采样频率是保障地面辐射温度测量精度的前提,与遥感像元尺度相匹配的地面真实性检验需要...     

Discussion on the Use of 7Be to Estimate Soil Erosion Rates

⁷Be is a naturally occurring cosmogenic radionuclide produced in the stratosphere and troposphere as a result of cosmic ray spallation of nitrogen and oxygen. The constant fallout via precipitation and short half-life (53.3 days), coupled with shallow depth distribution in soil profile (~2 cm) provide the unique advantages for its application as a soil and sediment tracer over short timescales, such as a single storm or short period of extreme rainfall. With the climate change and increasing rainfall events, the ⁷Be tracing method will exhibit wide application prospect in future. To date, however, this technique is still in its infancy and some important assumptions have not yet been effectively validated. Consequently, the use of ⁷Be to document soil erosion rates has been limited. This contribution briefly reviews the history and current status relating to this tracing method. In addition, the basic principles and recent research progresses in conversion models for use of ⁷Be measurements to estimate soil redistribution rates are introduced. The key assumptions and uncertainties of the technique, as well as the effects of the vegetation interception and particle size selectivity are discussed. Additionally, some new investigation directions are provided, including the assumption validation and uncertainty analysis, the impact of vegetation interception, the extending of spatial and temporal scales, and the development of new conversion models.     

Review of River Bank Erosion Research

Riverbank erosion is a critical style of lateral channel change. It threatens the arable land, ecological environment, as well as the people’s lives and properties along the river. Through review on the research process of riverbank erosion globally, four aspects were classified and described: ①Riverbank erosion processes and mechanisms. The occurence and development of riverbank erosion is quite complicated, composed by multiple processes, which are hard to separate with each other. Therefore, the scholars have proposed a lot of theories to describe the processes. Among the theories, “Riverbank Stability Theory” has been widely recognized and developed. ②Factors of riverbank erosion. The key factors that affect riverbank erosion include hydrology conditions of the river, soil properties, geomorphology, vegetation of the river bank and meteorology. However, it should be noted that the importance of different factors in the collapse process is not equivalent and effects of the same factor on different rivers are various. ③Riverbank erosion estimation. With the tremendous improvement of quantification recently, time interval of erosion measurement is shortening continuously, while spatial scale is larger and larger. At the same time, resolution is becoming increasingly high. Erosion pin was commonly used in early studies because of its easy use and low cost, whereas remote sensing and digital photogrammetry have more advantages in modern measurement. ④Modeling of riverbank erosion. At present, the models are mainly based on the fundamental theories of hydraulics and soil mechanics, to study river bank stability. According to the review of the four aspects above, problems of recent researches and prospects of possible development in the future were discussed. The researchers should pay much attention to temporal spatial distribution of riverbank erosion first before further research. The study would be greatly helpful to the researchers for the specific river reach when choosing the proper theories as well as technologies for measurement and quantification, study the riverbank erosion through both macroscopic and microscopic views, and predict the erosion for management purpose.     

Review on Correction of Errors in Precipitation Measurement

Accurate precipitation is the basis for better understanding the climate change and water cycle process. The domestic and foreign scholars have done a great deal of work for the insufficient catch rate of rain gauges. A review of recent studies on correction of errors in precipitation measurement was given in this paper. It is considered that the correction scheme for liquid precipitation is mature at present, but there is not a uniform standard for solid precipitation correction. The main reason is that the current precipitation correction schemes are lack of consideration of precipitation micro process. The full consideration of the precipitation micro process is the key to the correction of precipitation with physical significance. In addition, more detailed precipitation type determination and the record of light precipitation events are also key problems to determine the precipitation correction scheme.