Natural building stones

Natural stone due to its durable properties has been the choice of building materials since the very beginning of civilization. However, once stone is taken from its natural environment it begins to change to reach a state of equilibrium with its new environment. The polluted urban environment is a particularly hostile environment for natural stone and the effect on natural stone buildings, especially of historical or cultural significance, is a major cause for concern. Ongoing research into weathering studies is essential to provide a greater understanding of the processes that trigger stone decay and to ensure the implementation of successful stone conservation and replacement strategies.     

仇保兴:发展建筑节能与绿色建筑刻不容缓

在今年的两会上，以人为本，全面落实科学发展观，构建社会主义和谐社会．成为代表们议论的热点话题。而建筑作为一个高能耗的行业，势必要走在节能的最前沿。为此．我们特开辟“两会聚集”专栏，编辑整理了建设部郑部长和仇部长有关建筑节能的两次重要讲话，并专访了两会代表——北京建筑设计研究院顾问总建筑师李铭陶先生。     

Collision and mountain building

The spatial, chronological, and genetic relationships of recent (Late Alpine) collisions to mountain building are considered at three levels of scale: (i) in separate zones of the Arabian–Caucasus segment of the Alpine–Himalayan Orogenic Belt, (ii) throughout the central segment of this belt from the Alps to the Himalalayas, and (iii) in Central Asia and other mountain belts of continents. Three stages of mountain building are distinguished at all three levels. The first stage starts with widespread collision and similar plate interactions from the end of the Eocene to the middle Miocene and is expressed in the formation of uplifts, commonly no higher than the moderately elevated level in regions that concentrate deformations of transverse shortening induced by compression. The second short stage, which embraces the Pliocene–Quaternary and occasionally the end of the Miocene, differs in general, though differentiated in the value and intensification of vertical movements, when the height of mountains increases by 2–3 times. Elevations are spread over certain platform territories and even frameworks of rift zones. This is related not so much to the intensity of compression and shortening as to the compositional transformation of the upper mantle and the lower crust, leading to their decompaction. Comparison with the Hercynian and Caledonian orogenic stages shows that the second phase, predetermined by widespread collision, reflects a more important geodynamic event expressed in a change of the global plate interaction system and its deep-seated sources.     

Reducing the dimensionality of compositional data sets

The high-dimensionality of many compositional data sets has caused geologists to look for insights into the observed patterns of variability through two dimension-reducing procedures: (i)the selection of a few subcompositions for particular study, and (ii)principal component analysis. After a brief critical review of the unsatisfactory state of current statistical methodology for these two procedures, this paper takes as a starting point for the resolution of persisting difficulties a recent approach to principal component analysis through a new definition of the covariance structure of a composition. This approach is first applied for expository purposes to a small illustrative compositional data set and then to a number of larger published geochemical data sets. The new approach then leads naturally to a method of measuring the extent to which a subcomposition retains the pattern of variability of the whole composition and so provides a criterion for the selection of suitable subcompositions. Such a selection process is illustrated by application to geochemical data sets.     

基于粗糙集理论的区域降雨型滑坡预测预报

选择四川省雅安市雨城区为研究区域,以该区降雨型滑坡为数据样本,结合粗糙集理论,提取了研究区域的降雨因子和地质因子作为条件属性因子,利用粗糙集的计算机挖掘和智能知识发现功能,分析得到了预测降雨型滑坡发生与否的有价值的规则集。所生成的决策规则能够实现该区域滑坡的预测预报。研究结果表明:本方法较传统的统计方法更符合降雨型滑坡预测的非线性关系,而且考虑了地质因素的影响,较单纯降雨阈值的预测方法有更高的空间分辨率。     

Linear Richardson plots from non-fractal data sets

Richardson analysis, one of the principal methods of fractal analysis, is performed by measuring the perimeter of a curve with strides of varying length and constructing a log-log plot of perimeter against stride length. Certain simple geometrical forms can produce linear plots that mimic fractal behavior, and two smooth curves have been discovered that produce linear Richardson plots for strides varying by two orders of magnitude or more. The existence of such curves was not suspected before this study. Richardson analyses that suggest fractal geometry of low dimension or over a limited range of stride length should be checked against the source data for independent evidence of self-similarity.     

Evolution of orthogonal sets of coeval extension joints

The formation of two orthogonal sets of extension joints either crossing or abutting each other is a typical product of brittle deformation. Such systems of joints, with the two joint sets being geologically coeval, have been called a fracture grid-lock. The two sets are of common genesis and thus a unique remote stress field can be inferred. This interpretation causes some perplexity if the two joint sets are purely extension fractures and formed perpendicular to the least principal stress. In the present paper a conceptual model to explain the origin and the evolution of such systems is proposed. In a volume of rock undergoing a tensional and uniform remote stress state, caused for example by a tectonic regime, two horizontal and negative (i.e. tensional) stress rates are assumed to exist. When the tensile strength of the rock is locally reached, failure occurs perpendicular to the least principal stress. Then, that direction locally experiences a positive stress drop due to the stress release. For this reason, the stress field, retaining the same principal directions, is locally distorted by a swap between the σ₃ and the σ₂ components in a volume of rock surrounding the fracture. As a consequence of the persisting remote stress rates, when elastic failure conditions are newly accumulated, a second fracture forms and propagates perpendicular to the previous one. Repeated failure events, stress-drops and stress swaps eventually generate a fracture grid-lock. The whole process is also described with a simplified analytical model by applying elasticity theory.     

上海第二医科大学附属新华医院扩建病房楼医技楼

基于新华医院总平面布局现状，为最有效地组织新建病房楼、医技楼与已建门诊病房楼及内科病房楼等建筑物之间的各种流线关系，及各主要建筑间的总体外部空间关系，从建筑布局上使医院医疗功能得到充分发挥，丰富医院的外部空间环境，创造宁静、洁净、合理、高效的现代化医院的就医和工作环境。详见总平面图。     

深开挖工程中邻近建筑物的保护

深开挖工程中邻近建筑物的保护实质上是一系列控制地面变形的多级防护措施,主要包括：危险性评价,预防措施,深开挖监测,修改设计与施工方案和补救措施。     

Salt weathering in dual-porosity building dolostones

The influence of rock fabric on physical weathering due to the salt crystallization of selected brecciated dolostones is discussed. These dual-porosity dolostones are representative of heterogeneous and anisotropic building rocks, and present highly complex and heterogeneous rock fabric features. The pore structure of the matrix and clasts is described in terms of porosity and pore size distribution, whereas the relative strength for each textural component is assessed using the Knoop hardness test. The whole characterisation process was carried out using the same samples as those used in the standard salt durability test (EN-12370), including connected porosity, the water saturation coefficient, fissure density, compressional wave velocity and waveform energy.

Results show the most important rock fabric elements to be considered are the matrix and clast properties and the nature of fissures. Firstly, a relatively weak matrix was the focus of major granular disintegration as it presents high porosity, low pore radius and reduced strength. Secondly, narrow micro-fissures appear to be important in the decay process due to the effectiveness of crystallization pressure generated by salt growth. On the contrary, macro-fissures do not contribute greatly to rock decay since they act as sinks to consume the high supersaturations caused by growth of large crystals. Additionally, an analysis of stress generated by crystallization was carried out based on the general situation of a lenticular crystal geometry. Finally, the relationships between whole petrophysical properties and durability were established using a principal component analysis. This analysis has clearly established that the durability of rocks affected by salt crystallization mechanisms diminishes in weaker and anisotropic rocks with high porosity and fissure density.     

乌海市人民医院外科住院楼

一、总图构思 1、乌海市人民医院外科住院楼位于医院西北角。2、总图布置上在满足规划要求的前题下，尽量向西、北布置。体。3、为医院院落周边留出较大的绿化用地。4、同时也为医院今后的发展留出较多的空间。5、新建外科楼用连廊将原住院楼、门诊楼连为一体。     

Merging chironomid training sets: implications for palaeoclimate reconstructions

Icelandic and Norwegian chironomid calibration or training sets were merged to investigate whether a larger combined training set would be useful to apply to subfossil chironomid data from Iceland for periods such as the early Holocene, the Holocene Thermal Maximum and the Little Ice Age, when temperatures can be expected to be outside the current temperature range of the Icelandic training set. Following taxonomic harmonisation, the Icelandic and Norwegian data sets were compared before being merged to form a combined Norwegian-Icelandic training set. Analyses showed that it was biologically and statistically valid to merge the two data sets. The resulting combined inference model for mean July air temperature had improved performance statistics (r²_jack = 0.87; RMSEP_jack = 1.13) when compared to the best performing Icelandic model (r²_jack = 0.61; RMSEP_jack = 0.83), due to the longer environmental gradient covered (Icelandic 6–11 °C; combined 3.5–16 °C), and to the increased number of samples (Icelandic = 53 lakes; combined = 207 lakes) and taxa (Icelandic = 47 taxa; combined = 133 taxa) present within the combined training set. The inference models were applied to an early Holocene chironomid sequence from Vatnamýri, north Iceland, and a 450-year recent record from Myfluguvatn, north-west Iceland, to compare the reconstructions produced. The various inference models produced similar trends and patterns of temperature reconstruction, but the inference model based on the combined training set produced a larger range of reconstructed temperatures than the Icelandic model. It was found that different inference models produced more variation in the reconstruction than when different training sets were used. A comparison of the Myfluguvatn reconstructions with meteorological observations showed that the combined Norwegian–Icelandic inference model produced more reliable results than the Icelandic or Norwegian inference models alone.     

A new concept of mountain building

Mountain belts are constructed over periods of hundreds of millions of years from unrelated fragments carried across the ocean basins from distant sites, to be accreted along continental margins. Continental collision is an incidental rather than a necessary requirement for orogeny. Palaeogeographical reconstructions using the present geographical relationships of the fragments which make up orogenic belts are doomed to failure.     

浅析倾斜建筑物纠偏

本文主要由建筑物倾斜的主要原因、倾斜建筑物纠偏扶正的基本方法和倾斜建筑物纠偏程序三大部分组成。首先从①基础埋深较浅、岩土承载力受大气降水和斜坡坍塌影响较大;②建筑物受人类活动影响,水文地质条件发生了重大变化;③在建筑物附近开挖深基坑引起侧向卸荷;④建筑物所在斜坡失稳;⑤地震;⑥地下水流动带走地基土细颗粒等6个方面系统地分析了造成建筑物倾斜的主要原因;针对不同原因和倾斜建筑物结构特点,按浅基倾斜建筑物、深基倾斜建筑物和不稳定斜坡上的倾斜建筑物三大类型,详细地叙述了它们的纠偏加固方法及适用条件、优缺点;最后提出纠偏需要遵循的一般程序。     

异源点集下三维断层建模方法

用于断层建模的异源点集,因其具有不同特征而影响到建模途径和方法。以三维断层模型的3D GIS应用为目标,分析了原始地质观测点集、钻孔点集、剖面点集和平面点集的信息构成特征,提出了异源点集下三维断层数据模型的构建方法和流程。原始地质观测点集和钻孔点集间接表达了断层的空间特征,通过空间平面、曲面和曲线构建了断层面、地层面和断层交线的数学模型,并借助于连续模型的离散化,实现了独立断层建模点集的重建;剖面点集和平面点集可直接用于断层建模。以双TIN面模型为例阐述了断层三维模型的构建方法。     

基于粗糙集的膨胀土分级指标重要性分析

现行的膨胀土分级指标相互之间存在一定的关联,具有不同的重要性。提出了运用粗糙集理论完善和优化膨胀土胀缩指标体系的分析方法,通过计算膨胀土评判指标与评判结果的粗糙依赖度来确定评价指标的重要性。计算结果表明,自由膨胀率、膨胀力、50 kPa压力下的膨胀率和胀缩总率4个指标中,自由膨胀率是评判膨胀土胀缩等级的1个最重要的指标,膨胀力、50 kPa压力下的膨胀率和胀缩总率的重要性依次降低。所提出的分析方法为优化与改进膨胀土胀缩等级评判指标体系提供了合理而有效的依据。