GIS技术在土地利用环境适宜性评价中的应用

讨论了土地利用环境适宜性评价的模糊综合评价法,以模糊综合评价法的模型为基础,开发了一个基于MapObject的土地利用适宜性评价系统,以铜山县为例,对土地利用耕地水环境进行适宜性评价。     

A field index to determine the strength characteristics of crushed aggregate

The suitability of a simple technique to determine the strength characteristics of aggregates is reviewed. The results indicate that the strength characteristics of aggregates – in terms of crushing, impact and abrasion values – can be estimated and predicted from simple and quick tests for rock strength such as the Schmidt hammer and point load. The rocks and aggregates used in this work were of igneous, sedimentary and metamorphic origin and of different types, ages and degrees of weathering. More than 110 rocks and aggregate samples were tested according to British Standard and ASTM. The laboratory tests included the Schmidt hammer and point load for rock material while the crushing impact and Los Angeles abrasion test were undertaken on the aggregates. Regression analyses were performed and empirical relationships between the strength of rocks (in terms of their compressive strength and point load indices) and aggregates (in terms of their crushing, impact and abrasion values) were developed. Relatively strong relationships were obtained between the compressive strength of the rock and the crushing and impact value of the aggregate, while moderately strong relationships were obtained for the Los Angeles abrasion values. Electronic Publication     

集料级配对水泥稳定碎石的强度影响作用研究

从宏观力学角度研究了集料级配在水泥稳定碎石混合料强度中酊贡献作用,分析了不同粗细比和不同结构类型的混合料对其强度的不同影响作用,从而为施工控制提出了合理性建议。     

Influence of the quality of fine fractions on engineering-geological properties of crushed aggregate

Fine fractions of aggregate crushed from Finnish Precambrian crystalline bedrock were studied by determinining the particle size distribution with a Sedigraph particle size analyzer, specific surface area using the nitrogen adsorption method and porosity with a mercury porosimeter. According to abrasion resistance (Los Angeles) and brittleness (Swedish impact) values, all the materials studied were suitable as road aggregate. Roads where material with high specific surface area were used however soon proved to suffer from frost damage. No correlation between specific surface area and values of abrasion and brittleness were found. The specific surface area also proved to depend on the quality rather than the quantity of the fine fractions. Presence of clay minerals tends to increase the sp.s.a. Thus, in addition to the quantity also the quality of fine fractions must be analysed in road aggregate material.     

云南省部分农村消防水源建设研究

以当前云南省村镇消防水源现状为切入点,通过对云南省部分农村消防基础设施的调研,提出了已具备饮用水条件的云南省农村消防水源建设的建议,为农村消防基础建设提供参考。     

Trends of enrichment of free mica grains in crushed rock aggregates

The paper reports a study of the behaviour of free mica grains in crushed rock aggregates of metamorphic origin undertaken to identify any typical trends of enrichment with grain size. The mineralogical composition of the various grain size fractions was obtained using a polarizing microscope and point counting. Two general trends of enrichment of mica are presented: Type I (isotropic source rock) and Type A (anisotropic source rock). Type I is associated with a general increase in free mica towards the finer fraction, with or without a peak for “coarser” grain fractions. Type A is associated with an increase in free mica up to a certain grain fraction, after which there is a decrease with progressively smaller grain size.      

The influence of ophiolitic crushed fine aggregate properties on the performance of cement mortars

Bulletin of Engineering Geology and the Environment - Aggregates constitute the largest proportion of the raw materials used for the production of mortars. Therefore, their quality significantly...     

GIS在土地适宜性评价中的应用研究

对GIS在土地适宜性评价中应用的方法、模型、空间数据库的建立等问题进行了研究和讨论,同时指出GIS技术应用到土地适宜性评价中,可以大大提高评价的效率,保持评价定级的科学性、现势性和准确性,具有很好的应用前景.     

Spatial stability of slope cuts in rock massifs using GIS technology and probabilistic analysis

This paper presents a methodology for the stability analysis of cuts in rock slopes. A kinematic analysis of the different types of failure (planar, wedge, and toppling) is developed using GIS, following which a probabilistic analysis is made of the limit equilibrium in slopes where the conditions for kinematic failure are satisfied. The results were verified by comparing the evaluation against the observed stability conditions in 40 road cuts along 4?km of national road N-340, on the Mediterranean edge of Granada province (southern Spain). The validation analysis showed that for some 90% of the slopes studied there was a reasonable fit between the observed and evaluated stability, indicating the proposed methodology is suitable for the preliminary analysis of the stability conditions on rock slopes.     

黄岛区破碎岩质高边坡支护设计与施工

以青岛经济技术开发区一经济适用房小区内的边坡支护工程为例,介绍了锚杆和A5面的设计方案及施工流程和注意事项。经过后期的监测,通过以上加固措施,能够有效提高边坡的稳定性和安全性,为创造美观、安全的小区环境提供有利条件。     

水泥稳定碎石基层骨料堆积密度计算方法

将水泥稳定碎石骨料堆积形态视为球状颗粒堆积模型,在Stovall等人推导的堆积密度公式的基础上建立了水泥稳定碎石基层骨料堆积密度计算方法,并通过试验拟合了公式中的待定参数,试验表明用该公式可计算不同粒径分布的水泥稳定碎石的堆积密度。     

Identification of rockfall source areas using the seed cell concept and bivariate susceptibility modelling

The objective of this research was to prepare a rockfall susceptibility map. Explorations were conducted in the Dubra?ina River basin (Croatia). The input data included a geological map, an orthophoto and a 1-m digital terrain model (DTM). After a talus inventory was prepared, the seed cell concept was applied to define the rockfall source areas. The contributing factors (predictors) of rockfalls were evaluated by the chi-squared test. The analysis confirmed the following predictors: CORINE land cover, lithology, slope, aspect, distance from a spring, distance from a road, distance from a fault, distance from a stream, and distance from the rock-soil geological boundary. A matrix pairwise comparison of the predictor ratings was used to define the most significant contributing factors. The predictors that affected the susceptibility map in the share of 86.3% were the slope (61.6%), lithology (13.4%), CORINE land cover (6.2%), and distance from the rock-soil geological boundary (5.1%). Two susceptibility maps were prepared: one using all nine contributing factors and another using the four most significant factors. The analysis showed that both maps were good, with the same areas under the receiver operating characteristic (ROC) curves. The map prepared with only four contributing factors can be considered a better map due to its more precise spatial definition of critical areas. It can be concluded that geological map, 1-m DTM and orthophoto provide enough data to prepare reliable rockfall susceptibility map. The application of the bivariate statistical zonation method called the “frequency ratio method” was proven to be successful. This research demonstrates that the application of the seed cell concept can be useful to speed up the process of rockfall source area detections in large research regions.

     

Evaluation of the mechanical degradation of carbonate aggregate by rock strength tests

Aggregate degradation (AD) is one of the major reasons accounting for failure of aggregate materials, and the mechanical degradation of aggregate materials can be determined by different test methods. This process basically requires many aggregate samples and special instruments, and thus is time-consuming. The main purpose of this research is to evaluate the possibility of estimating the AD characteristics using rock strength tests and to investigate the relationships between AD properties and rock strength tests. For understanding the relationships, two common rock strength tests are employed, i.e. unconfined compressive strength (UCS) and point load index (PLI) tests. In the tests, the AD properties of 40 kinds of carbonate aggregates sampled from Iran were studied. The AD properties were determined by Los Angeles abrasion value (LAAV), aggregate impact value (AIV) and aggregate crushing value (ACV). Also, the samples are classified according to the strength and rock types, and the effect of this classification is investigated based on the relationship between rock strengths and AD properties. The results indicate that the PLI is better than UCS for evaluation of AD properties. Among rock strength tests, PLI has a closer relationship with AIV (R² = 0.832). Also, UCS has relative larger effects on the ACV (R² = 0.812) under the same loading condition. The weakest correlation occurs between LAAV and UCS (R² = 0.679). In view of the rational AD properties in the predictive procedure, it is possible to predict AD properties based on the strength tests and rock types. The results also show that the prediction of AD properties using rock strength test based on rock types yields better correlations than that using unclassified samples. The classification based on rock types can extrapolate the different relationships of AD prediction from rock strength tests. The results in this context could be used for preliminarily selecting proper rock aggregates with a limit of allowable AD tests for practical applications by PLI.     

稻花香里说新村——江西赣州市新农村建设掠影

七月流火。极目赣南田野,绿深稻黄,更有如画村庄点缀在绿水青山。因为小学课本上《吃水不忘挖井人》的文章,瑞金市沙洲坝镇沙洲坝村名扬四海。“沙洲坝,沙洲坝,三天不下雨,没水洗面帕”。当年,毛主席带领红军和乡亲们在村中挖了一口井,沙洲坝人时刻不忘毛主席。如今,村民们看到一根根洁白的自来水管,一股股清亮的“幸福水”、“致富水”流进家里,心里更是乐开了花。仅靠几亩贫瘠干旱的薄田谋生的日子一去不复返了。该村建成了农民篮球场,设立了农民活动室,成立了烟叶生产协会、蘑菇生产协会、旅游产业协会,还对紧靠“红井”的18家农户的房屋…     

寒冷地区再生混凝土抗冻性能试验研究

再生混凝土的研究意义重大,其抗冻性则是影响其应用的重要指标.主要通过冻融循环试验研究了不同粗骨料取代率的再生混凝土的抗冻性,从冻融循环过程中混凝土试件的表面现象、质量损失及相对动弹模量3个方面进行阐述.     

Multi-dimensional evaluation and ranking of coastal areas using GIS and multiple criteria choice methods

Coastal ecosystems are increasingly threatened by short-sighted management policies that focus on human activities rather than the systems that sustain them. The early assessment of the impacts of human activities on the quality of the environment in coastal areas is important for decision-making, particularly in cases of environment/development conflicts, such as environmental degradation and saturation in tourist areas. In the present study, a methodology was developed for the multi-dimensional evaluation and ranking of coastal areas using a set of criteria and based on the combination of multiple criteria choice methods and Geographical Information Systems (GIS). The northeastern part of the island of Rhodes in the Aegean Sea, Greece was the case study area. A distinction in sub-areas was performed and they were ranked according to socio-economic and environmental parameters. The robustness of the proposed methodology was assessed using different configurations of the initial criteria and reapplication of the process. The advantages and disadvantages, as well as the usefulness of this methodology for comparing the status of coastal areas and evaluating their potential for further development based on various criteria, is further discussed.     

新型矿物骨料耐磨地面在工程中的应用

结合工程实例,针对工程特点,对新型矿物骨料耐磨地面的施工工艺进行了阐述,总结了其质量及安全控制措施,并对其经济效益与使用效果进行了分析,指出矿物骨料地面具有抗冲击、耐磨等优越性。     

Applying rock mass classifications to carbonate rocks for engineering purposes with a new approach using the rock engineering system

Classical rock mass classification systems are not applicable to carbonate rocks, especially when these are affected by karst processes. Their applications to such settings could therefore result in outcomes not representative of the real stress–strain behavior. In this study, we propose a new classification of carbonate rock masses for engineering purposes, by adapting the rock engineering system (RES) method by Hudson for fractured and karstified rock masses, in order to highlight the problems of implementation of geomechanical models to carbonate rocks. This new approach allows a less rigid classification for carbonate rock masses, taking into account the local properties of the outcrops, the site conditions and the type of engineering work as well.     

Assessment of a microgranite source rock for use in concrete

A microgranite, showing varying degrees of weathering with depth, has been investigated as a source of concrete aggregate for dam construction. Diamond drilled cores and percussion drilled samples, taken to 40 m depth, were used for mineralogical, petrological, and methylene blue dye adsorption (MBA) studies and for measurement of drying shrinkage in order to assess the influence of deleterious secondary minerals, largely swelling clays, on the dimensional stability of the rock. A highly significant correlation between MBA and drying shrinkage indicated that samples which had MBA values less than 1.5 mL/g would produce concrete shrinkages acceptable for structural purposes.     

Experimental study of the hydro-mechanical behavior of rock joints using a parallel-plate model containing contact areas and artificial fractures

In recent years, geological disposal of radioactive wastes is considered to be the most promising option, which requires the understanding of the coupled mechanical, hydraulic and thermal properties of the host rock masses and rock fractures. The hydro-mechanical behavior and properties of rock fractures are usually determined by laboratory experiments on fracture specimens that serve as the basic building block of the constitutive models of fractured rock masses.Laboratory testing of rock fractures involve a number of technical issues that may have significant impacts on the reliability and applicability of the testing results, chief among them are the quantitative estimation of the evolutions of hydraulic transmissivity fields of fractures during shear under different normal constraint conditions, and the sealing techniques when fluid flow during shear is involved. In this study, a new shear-flow testing apparatus with specially designed fluid sealing techniques for rock fractures were developed, under constant normal load (CNL) or constant normal stiffness (CNS) constraint. The topographical data of all fracture specimens were measured before testing to constitute the geometrical models for simulating the change of mechanical aperture distributions during shearing. A number of shear-flow coupling tests were carried out on three kinds of rock fracture specimens to evaluate the influence of morphological properties of rock fractures on their hydro-mechanical behaviour. Some empirical relations were proposed to evaluate the effects of contact area and surface roughness on the behavior of fluid flow through rock fractures.