The basalt stone quarries of eastern India

Quarrying of basalt stone in the Early Cretaceous Rajmahal Trap region of eastern India is increasing at an alarming pace. The quarries have created an extensive ugly landscape of pits and overburden dumps. The stone workshops continuously emit dust. These quarries generate year‐round employment in an impoverished terrain. The workforce mostly comprises the socio‐economically deprived indigenous tribal population. They are an important source of income to the State Governments of Jharkhand and West Bengal. While the need for building stone cannot be denied in a region that is rapidly industrialising and urbanising, issues of land degradation and health cannot be ignored. The paper offers measures to contain environmental degradation and generate alternative sources of income with bio‐fuel crops such as Jatropha curcas.     

Geometric quality assessment of in situ blocks in dimension stone quarries

The profitability of stone quarries depends on the appearance (color and texture) and, more importantly, on the size of the blocks, which is determined by the three-dimensional discontinuity pattern of the rock mass. However, to date there is no comprehensive criterion by which to assess the size of blocks in quarries. The aim of the study reported here is to identify factors that facilitate decision-making on the desirability of an individual block and ultimately on all blocks for extraction as a dimension stone. To this end, we first developed a novel algorithm to calculate the largest rectangular parallelepiped that can be placed inside a block and then defined a regularity factor (α) and a quarry block shape factor (q) that enable the geometric quality of the block to be assessed more accurately than currently possible. The sensitivity analysis of these factors showed that the change in angle relative to the change in spacing has the greater effect on the geometric quality. The proposed factors displayed a good performance in a comparison analysis of four sites of the Dareh Bokhari travertine quarry complex located in Mahallat, Markazi province, Iran. Based on the results, blocks at sites 2 and 4 have the lowest and the highest geometric quality, respectively, which is in accordance with the operational conditions at the respective sites. Moreover, comparison of the values of factor q obtained from applying various cutting planes indicated that to maximally increase block production capacity, the current cutting direction at site 4 should be adjusted 33° eastward.

     

Dynamics of capillary water absorption in natural stone

Two natural carbonate stones from Croatia (Kirmenjak avorio and Veselje unito) were analyzed to assess their properties for use in masonry buildings. The results indicated considerable differences in the water absorption (expressed in g/m²) shown as a function of elapsed time. The petrographic analyses highlighted different characteristics as important for the absorption of water in natural stone, including composition, structure, texture and pore system. The importance of assessing the movement of water in the stone relative to its bedding and the construction in which it will be placed is emphasized.     

天然沸石在水处理中的应用

介绍了天然沸石的组成，从其对放射性废水的处理、氟离子、重金属离子、氨离子的去除等方面进行了论述，指出天然沸石是一种潜在的很有远景的矿产资源。     

Investigation of natural biofilms formed during the production of drinking water from surface water embankment filtration

Populations of bacteria in biofilms from different sites of a drinking water production system were analysed. Polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analyses revealed changing DNA band patterns, suggesting a population shift during bank filtration and processing at the waterworks. In addition, common DNA bands that were attributed to ubiquitous bacteria were found. Biofilms even developed directly after UV disinfection (1-2m distance). Their DNA band patterns only partly agreed with those of the biofilms from the downstream distribution system. Opportunistic pathogenic bacteria in biofilms were analysed using PCR and Southern blot hybridisation (SBH). Surface water appeared to have a direct influence on the composition of biofilms in the drinking water distribution system. In spite of preceding filtration and UV disinfection, opportunistic pathogens such as atypical mycobacteria and Legionella spp. were found in biofilms of drinking water, and Pseudomonas aeruginosa was detected sporadically. Enterococci were not found in any biofilm. Bacterial cell counts in the biofilms from surface water to drinking water dropped significantly, and esterase and alanine-aminopeptidase activity decreased. beta-glucosidase activity was not found in the biofilms. Contrary to the results for planktonic bacteria, inhibitory effects were not observed in biofilms. This suggested an increased tolerance of biofilm bacteria against toxic compounds.     

天然石材产品干燥压缩强度测量不确定度评定

充分考虑影响因素,对天然石材产品干燥压缩强度测量度不确定进行评定     

超薄天然石材的对剖式切割技术

本文向读者介绍了当前在国内切割加工超薄天然石材的设备现状以及作者多年来对超薄天然石材加工的研究成果，对超薄天然石材的市场现状和发展前景作了深入的分析和预测。     

天然真石漆施工方法

为了满足建筑物特殊使用功能的要求,提出了喷涂天然真石漆的施工工法,对天然真石漆的特点及适用范围作了论述,就其工艺流程、操作要点、质量要求、安全注意事项、成品保护、综合效益等进行了分析.     

《天然石材用水泥基胶粘剂》标准解读

介绍了JG/T355-2012《天然石材用水泥基胶粘剂》建工行业标准的编制过程,按照标准章节对该标准的技术内容进行了介绍,并对标准主要条文进行了解读。     

天然石材的放射性概念及选用建议

天然大理石、花岗石,由于其资源丰富、品质优良、物美价廉,使用效果耀眼醒目,美化家居生活,逐渐成了室内装饰材料中的新宠.近年发展速度惊人,更引起了人们的普遍关注.     

Dynamic behavior of a Mediterranean natural stone under tensile loading

Historical buildings are important structures commonly occurring in Mediterranean cities. The behavior of their constituent materials under high dynamic loads is fundamental to investigate the vulnerability of such structures under extreme dynamic events. The main aim of our investigation was to study the effect of high dynamic loading conditions on a classical porous natural stone from the Naples area, namely yellow tuff, used in hundreds of historical buildings and monuments in Naples and other Mediterranean cities. Hence, dynamic characterization was performed through high strain-rate failure tensile tests. A wide range of strain-rates was investigated, from 10^?5 s^?1 to 50 s^?1. The obtained data were processed to obtain stress–strain relationships at different strain-rate levels. The results reveal that Neapolitan yellow tuff presents a significantly strain-rate sensitive behavior, exhibiting dynamic tensile strength increasing with strain-rate, up to about three times that from quasi-static conditions in the case of very high strain-rates. Dynamic increase factors (DIFs) vs. strain-rate curves for tensile failure stress were also evaluated and discussed.     

新型复合天然石板的研制与开发

本文作者所研制的新型复合天然石板,是采用3～5mm厚的天然大理石薄板与轻体复合材料经特殊工艺加工复合而成,可广泛应用于建筑物内外墙面、地面的建筑装饰,该产品已获国家专利,专利号为ZL 96241876.5。     

Characteristics and the environmental acceptability of the natural stone quarrying waste rocks

The paper summarises the results of a study by the Geological Survey of Finland on the potential use of waste rocks from natural stone quarry production. Petrographic, chemical, mechanical and physical tests were undertaken on granite, rapakivi granite, migmatite, syenite, diorite, gabbro, anorthosite gabbro, schist and soapstone from 33 dimension stone quarries in Finland. The results indicate the waste rocks of Finnish natural stone quarries can generally be considered environmentally sound with potential uses in other industries.     

大比例天然石料制作高性能人造花岗石生产工艺

人造花岗石用作建筑装饰材料被人广知,是由氢氧化铝等填充料与树脂粘结料如不饱和聚酯、丙烯酸等树脂固化成形,虽具有良好的加工性,但难燃性、耐磨性和耐擦伤性不足,用于墙地面受到制约.不饱和聚酯树脂用作粘结料与天然大理石等碎粒混合成形,因耐候性差,紫外线照射下易泛黄.此外,人造花岗石用树脂粘结料使用由丙烯酸单体成分与其聚合体成...     

Design and construction recommendations to improve impermeability in rainscreen walls built with natural stone coverings

In current European construction, the building model of stone coverings detached from the building support is being increasingly used. These coverings remain joined to the rest of the façade only by certain anchorage points, leaving thus a cavity between the stone panels and the inner support. This is the model that best adapts to the actual concept of heterogeneous façade, with high performance qualities and predictable behaviour.Walls designed to achieve a high degree of air pressure equalization between the inner cavity and the exterior, obtaining considerable benefits, are known as Pressure Equalized Rainscreen (PER) walls. Existing design guidelines on these walls are mainly qualitative and referred to a theoretical continuous wall, with few references to real construction methods or discontinuities of the façade.Behaviour of PER walls, when built with stone panels of medium thickness (30–40 mm) and open horizontal and vertical joints, is analysed in this study, based on the climate in the city of Valencia (Spain). Although panels of 12–20 mm thickness are often used in many countries, the Spanish Technological Standards recommend using panels of at least 30–40 mm in this type of façades, being thus this thickness the most common in Spain. The aim of the study is to understand rainscreen wall performance in this case, with regard to water coming into contact with the façade, and thus propose several design and construction recommendations to improve impermeability in crucial points of the façade.     

钻孔液在旋挖钻钻孔施工中的应用

结合工程实例,介绍了钻孔液在旋挖钻钻孔施工中的优势,简述了新型钻孔液的适用范围及工艺原理,并阐述了其施工工艺流程及操作要点,提出了施工的质量、安全、环保控制措施,指出钻孔液具有工期短、质量高、成本低等特点,值得推广应用。     

Slope geometry design as a means for controlling rockfalls in quarries

This paper presents a rockfall control method for rock quarries, based on benched rock slope design and catch-bench width control. The aim is to prevent rockfalls in quarries, which cause a significant number of accidents and even fatalities. Whereas catch ditches have traditionally been used as the main rockfall control method for roads and highways, benches carved into slopes are typically used in open-pit mining. In the road engineering field a simple empirical technique, recently reviewed and updated, has long been in use that is capable of ensuring slope designs that prevent falling rocks from reaching the travelled area of a road. Such techniques are lacking in the quarrying field, however, and this work is an attempt to develop a method similar to those developed for road engineering, but specifically adapted to quarry slope geometries. Using statistically significant data on the parameters affecting falling block trajectories, obtained from empirical data and from a back-analysis performed using a rockfall modelling code, we estimated geometries for quarry slopes that would prevent falling rocks from reaching work areas. This information was compiled and presented in the form of charts (for 2-bench, 5-bench and 8-bench slopes) that enable the user to design rockfall-safe slopes.     

The hole drilling technique for on site deduction of the stresses states in stone masonry by using eight strain gages

The hole drilling technique for the on site deduction of the stresses in structural elements of cultural heritage structures has been applied on two monuments: the Saint Jakobs Church (Leuven, Belgium) and the Cathedral of Tarazona (Zaragoza, Spain). The adjustment of the technique becomes an experimental methodology very different from the one employed for the deduction of residual stresses. There are two main differences in the experimental methodology: the experimental dimensions are thirty times greater and eight strain gages are placed instead of three. The latter is done to have sufficient redundancy in the system and to be able to make an objective analysis of the quality of the results. The paper basically deals with the derivation of the stress states from the strains caught by the eight strain gages in agreement with the general methodology of the hole drilling technique.     

Estimating rock properties using sound levels produced during drilling

An attempt has been made in this paper to experimentally investigate the estimation of rock properties like compressive strength and abrasivity using sound levels produced during drilling. The investigation was carried out on a laboratory scale using small portable pneumatic drilling equipment used in hard rock drilling. For this purpose, a pneumatic drill setup was fabricated for drilling vertical holes. The compressive strength and the abrasivity of various rock samples collected from the field were determined in the laboratory. A set of test conditions were defined for measurement of sound level of the pneumatic drill. Also, with the help of the experimental setup, vertical drilling was carried out on the rock samples for varying thrust and air pressure values and the corresponding A-weighted equivalent continuous sound levels were measured. Results of this study indicate that sound level can be a promising tool in estimating rock properties during drilling.