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1.
The stone pagoda of the Bunhwangsa temple in Republic of Korea was made of piling small brick-shaped stones. The majority
of stone bricks are andesitic rocks with variable geneses. Rock properties of the pagoda roof suffer partial significant deterioration,
such as multiple peel-offs, exfoliation, onion-peel-like decomposition, cracks forming round lines and falling-off stone pieces.
The stylobates and tabernacles at the four corners are composed of granitic rocks, which are heavily contaminated by lichens
and mosses. Some of these contamination marks show dark black or yellowish brown colors by inorganic secondary hydrates. The
four tabernacles and northern face of the pagoda body have been exposed to relatively high humidity, which causes light gray
efflorescence as stalactites between the northern and western sides of the body. The efflorescences are composed of calcite,
gypsum and clay minerals. The stone lion statues at the southeast and northeast corners are made of alkali granite, while
the others are lithic tuff. Total rock properties of the pagoda consist of 9,708 stone bricks. Among them, 11.0% are fractured,
6.7% are fallen off, and 7.0% show considerable surface efflorescence, which shows that the pagoda has been highly deteriorated
by physical, chemical and biological weathering. The authors strongly suggest long-term monitoring and comprehensive conservation
researches. 相似文献
2.
The Bulkugsa Dabotap pagoda was built in AD 761, and designated as World Cultural Heritage by UNESCO in 1995. The ca. 270 blocks used in the construction of the pagoda consist mainly of white grey alkali granite with medium-grained equi-granular texture and small mialolitic cavities. Small quantities of biotite granite, granodiorite, gabbroic and tuffaceous rocks were also used. Some overlapping blocks are very damp. The pagoda body is inclined toward the northeast owing to differential loading. Fractures and artificial deterioration of the pagoda are not serious, but the surfaces of blocks show exfoliations that indicate granular decomposition of minerals. The supporting rocks and the round handrail of the octagonal second floor are too weathered to be treated and are being replaced. The roof stones on the first and second floor are seriously damaged because there is no drainage route for rainwater. The joints between blocks have fractures that cross each other; they have been further damaged by inserting concrete, cement mortar, rock fragments and iron plates. This has accelerated discoloration and fractures. Widespread colonization by algae, fungi, lichens and bryophytes has occurred on the margins and surfaces roof stones of the pagoda. Chemical treatment will be necessary to remove the vegetation cover. 相似文献
3.
Yılmaz Mahmutoğlu 《Environmental Earth Sciences》2017,76(12):435
Engineering properties of building stones can vary because of degradation by weathering agents. Thermal fluctuation is one of the most important agents on deteriorations such as sugaring, bowing, cracking and spalling of marble. As a result, physical and mechanical properties of marble used in the construction of old and/or modern structures are adversely affected by time. On the other hand, some properties of building stones are always required for decision of rehabilitation works. Several kinds of conventional tests have been suggested for characterization of stones, to measure their properties or to evaluate conservation or repair works. However, in most cases, sampling from historical buildings is not possible. Therefore, nondestructive testing methods are often suggested for the prediction of weathering grade of building stones. One of the most practical methods for similar purposes is ultrasonic pulse velocity measurement, which can be performed easily. The main goal of this study is attainment of sound empirical correlations between the ultrasonic pulse velocity and engineering properties of previously deteriorated marble. Experimental works were conducted on seven different specimen categories of a coarse-grained marble having different micro-crack frequencies induced by both cyclical heating–cooling and freeze–thaw actions. The experimental results indicated that physical and mechanical properties of Mu?la marble can be reliably estimated for different environmental cases by ultrasonic pulse velocities. P-wave velocities in dry and saturated cases are two sound indicators of both the apparent porosity and the coefficient of capillary absorption, and whereby the sugaring type of deterioration for coarse-grained marbles. 相似文献
4.
介绍了建筑用石材质量检测的相关规范、内容及检测方法,总结了超声技术应用在石材检测中的经验,讨论了石材质量与超声波的波速、振幅的关系. 相似文献
5.
The results of the geological characterization of an old stone building in southern Italy, are presented here. The Mondragone marble is a slightly metamorphosed carbonate rock, which was widely employed as monumental stone in the 18th century Royal Palaces of Naples and Caserta. In this paper, for the first time, this rock has been investigated with a thorough laboratory testing program, aimed at defining its mineralogical, physical and mechanical parameters. The two most important varieties of Mondragone marble were separately tested: the yellow and grey marbles (hereafter, YM and GM, respectively). The results obtained from physical tests (open porosity, dry density, specific gravity, water absorption coefficients, ultrasonic velocity) did not show marked differences between the two materials; in contrast, the mechanical strength tests (uniaxial compressive strength, point load strength, flexural strength) showed better behaviour of YM than for GM. After a tentative comparison with other well known carbonate rocks from Italy, some considerations on the response of Mondragone marble to local weathering were conducted. In particular, the weathering typologies were related to the particular texture of the brecciated marble and the different strength resistances displayed by the various constituents of the rock. 相似文献
6.
北京有大量采用房山大理岩制造的石质文物,这使得北京大理岩力学性质的研究对于科学指导文物保护和修复具有重要意义。但由于文物本体取样困难,难以获得其力学参数。因此本文对北京大理岩的物理、力学参数进行测试,通过建立物理参数和力学参数的回归方程,实现利用物理参数评价力学参数的目的。以北京大理岩中的青白石和汉白玉为研究对象,对8个边长为150 mm立方体试样进行施密特回弹测试,对40个Ф50 mm×100 mm的圆柱体试样进行里氏硬度、纵波波速测试和单轴压缩试验,得到了大理岩的回弹值、里氏硬度值、纵波波速与单轴抗压强度、弹性模量。分别以单轴抗压强度和弹性模量为因变量,选择单个或两个物理参数作为自变量建立回归方程。通过对比相关系数发现:（1）对于单个物理参数,单轴抗压强度与D探头里氏硬度值的相关性最好,而弹性模量与回弹值的相关性最好;（2）对于两个物理参数,单轴抗压强度（或弹性模量）都与回弹值和D探头里氏硬度值的组合相关性最好。 相似文献
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Forestieri Giulia de Buergo Mónica Álvarez 《Geotechnical and Geological Engineering》2021,39(7):5021-5040
Mendicino calcarenite was once widely used in traditional constructions by Italy’s foremost stonemasons’ schools. This paper provides a complete physico-mechanical characterization in order to improve understanding of strength and durability properties and so apply that knowledge to conservation and new construction. Stone samples from three lithofacies are taken from the following quarries of Cosenza province: Scannelle in Malito; Cannataro in Carolei; Albanese in San Lucido. Samples are subjected to: X-ray diffraction, mercury intrusion porosimetry, ultrasonic pulse velocity, capillary water absorption, uniaxial compressive, flexural, point load tests with respect to the X, Y, Z axes. Malito samples exhibit creamy colour, better hydric behaviour, low open porosity, reduced water absorption capability, isotropic hydric behaviour, higher fossil abundance (both in number and size) than the lithofacies taken from Carolei and San Lucido, which exhibit whitish colour, greater strength and more homogeneous texture. The greater compactness of Carolei and San Lucido samples can be ascribed to homogeneity and low porosity and their better mechanical properties to textural features. Anisotropy plays an important role. Placing stone samples along the Z axis prevents water intrusion, and improves mechanical strength. Isotropy and compact and heterogeneous fabric in stones result in higher strength and lower water absorption.
相似文献9.
石少敏 《吉林大学学报(地球科学版)》2011,41(1):172-176
振冲碎石桩为散体结构,所形成的复合地基受垂直荷载后的变形较刚性桩复合地基要大,为研究振冲碎石桩复合地基的沉降规律,建立振冲器动力性能指标与碎石桩桩体强度的关系。根据压缩模量概念,结合振冲桩制桩工艺,建立桩体压缩模量与振冲器激振力、施工中的加密段长、加密电流及留振时间的关系式-动力法。采用动力法和载荷试验法所得的压缩模量在沉降量计算中进行对比,结果与按实际观测推算值的偏差均小于10%。 相似文献
10.
节理岩体超声测试及单轴压缩试验研究 总被引：1，自引：0，他引：1
为了获取节理岩体各向异性力学特性和声波传播规律的相互关系,通过制作圆柱形单一预制贯通节理试件,开展了7种不同倾角节理试件的超声波波速测试和单轴压缩试验。试验结果表明：（1）节理试件波速测试值离散性较大,但总体服从正态分布,波速平均值介于石膏试件和完整试件之间,波速随节理倾角增大呈线性递减;（2）不同倾角的节理面对节理试件力学特性的影响很大,在应力-应变关系、变形特征、强度特征和破坏模式上均表现出显著的各向异性特征;（3）节理试件的力学性质和超声波传播特性变化规律区别很大,采用超声波波速确定节理试件的力学参数会存在很大误差。 相似文献
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12.
İsmail İnce Ali Bozdağ M. Bahadır Tosunlar M. Ergün Hatır Mustafa Korkanç 《Environmental Earth Sciences》2018,77(11):420
Building stones have long been one of the most widely used construction materials in the world. Building stones used in historical monuments are deteriorated partly or completely depending on the environmental and atmospheric effects. In recent years, non-destructive test methods have been used to assess deterioration of building stones used in historical monuments. Gödene stone is one of the building stones being widely used in the historical buildings in the Konya region, Central Anatolia. The most deterioration effects are observed in the Ferit Pa?a Cistern among the historical structures built with Gödene stone in the region. The aim of this study is to assess the deteriorating effects in the street façade of the Ferit Pa?a Cistern via non-destructive testing methods (Schmidt hardness rebound value, P-wave velocity, humidity measurement and thermal imaging) and create maps of deteriorated features. Turkey’s historic places are integrated to Turkish culture, efforts are made to conserve heritage through rehabilitation. Therefore, this study will help developers and federal managers during the project planning stage by providing technical data. 相似文献
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14.
基于岩石损伤理论推导了冻融循环作用下岩石的损伤劣化模型,并采用冻融循环试验方式测试了后崴子隧道灰岩岩样冻融循环后的物理力学特征变化规律,分析了其损伤劣化规律。获得了岩样的质量、纵波波速随冻融循环呈现先增后减的趋势,单轴抗压强度持续减小,弹性模量和峰值应变逐渐增大的结果。分析获得了冻融循环作用下灰岩总损伤变量与应变的关系,冻融和载荷的共同作用会使总损伤加剧,但损伤曲线表明耦合作用也可适当缓解这一影响,且灰岩应变值趋于一致,表明影响灰岩强度极限的主要因素可以不考虑冻融循环。 相似文献
15.
抛石爆破挤淤的过程主要分为4步。第1步是直接进行抛石挤淤;第2步是在堤头前方的淤泥内进行首次堤头爆破,使淤泥的强度降低,抛石和淤泥之间的平衡被打破,抛石向淤泥内滑移和下沉,直至达到新的平衡;第3步是补填后再次进行爆破,并依次循环;第4步是每50m进行一次侧爆。通过改变淤泥强度的方式来代替爆破作用,利用有限元数值模拟方法对这4个过程进行了模拟,在此基础上进行了挤淤效果的预测。通过工程实例,进行了理论预测与钻探、探地雷达实际检测结果的对比,证实数值模拟的结果是正确的。模拟结果表明经过抛石爆破挤淤4个步骤的处理,抛石最终会形成稳定的马蹄形海堤。 相似文献
16.
煤层水力压裂模拟实验是研究煤矿井下水力压裂煤岩体致裂增透、弱化机理的有效手段。然而,大尺寸煤岩体原位保真取样技术不成熟,已有大尺寸煤样块多取自卸压区,其在运输和制备过程中会发生二次破坏,导致实验结果失真。因此,使用煤岩体相似材料代替大尺寸原煤执行室内水力压裂模拟实验成为一种可行的选择。煤岩体相似材料试样的力学特性是影响水力压裂效果最重要因素。为精确表征煤岩体相似材料的基础力学特征,选择煤粉、水泥、石膏、砂子为相似材料,设计制作7种配比试样,进行超声波与力学特性耦合响应规律研究。结果表明:煤岩体相似材料试样超声波波速(P波和S波)和强度(单轴抗压和抗拉强度)随着密度的增大而增大,随着孔隙率的增大而减小;相似材料对于超声波波速、强度和密度增大幅度的影响为水泥>砂子>石膏,孔隙率正相反;相似材料水泥和石膏分别在调节试样强度和变形特性方面起主要作用;根据超声波P波波速与强度之间的二次多项式数学模型,通过测定超声波P波波速可提前预测试样的强度;试样力学参数可调整范围大,通过改变相似材料配比可以调整试样的力学性质,精确模拟煤岩体,且试样制作方法简单。此研究可为煤层水力压裂模拟用煤岩体相似材料力学特征相似设计提供依据,促进矿井瓦斯防治技术的发展,具有广泛的应用价值。 相似文献
17.
Wanja Wedekind Christian J. Gross Andreas Hoffmann Siegfried Siegesmund 《Environmental Earth Sciences》2018,77(21):735
Sandstones, clay in the form of bricks and laterite are the building materials used by the Khmer to construct the imposing and magnificent temples in Southeast Asia. Many of these monuments suffer from fracturing, sanding, contour scaling, crust formation and salt weathering. The affinity to weathering is closely connected to the type of material. Two sandstone types classified as feldspathic arenite and quartz arenite of Angkor as well as two arkosic sandstones from Thailand are described and investigated in this study. Important petrophysical properties determined for the different sandstones consist of hydric expansion, thermal expansion, pore radii distribution and ultrasonic velocity. Different investigations such as capillary water uptake, surface hardness, hygroscopic water sorption, and salt resistance tests were undertaken in the laboratory to characterize the various rock types. Observations and quantified damage mapping were done onsite at the Phnom Bakheng Temple. Contour scaling in the form of weathering crusts is one of the main deterioration features observable at the Angkor monuments. Comparisons are made between the building stone, the crust material from the Phnom Bakheng Temple and fresh stone material used for restoration. Significant differences in hydric and especially in thermal expansion of the crust and sandstone have been determined. The results seem to indicate that extensional processes occur, which can be considered a force for detachment (i.e., contour scaling, flaking). In an experimental trial, the hydric and thermal expansion of the weathering crust and the building stone was significantly reduced by using a weak acid for the crust and a swelling inhibitor for the original building stone. 相似文献
18.
软弱夹层特性对地震波强度影响的模拟研究 总被引：7，自引：2，他引：7
模拟了隐伏软弱夹层的弹塑性参数对其地震波放大效应的影响,发现当软弱层波速不大于上下围岩的 30 %时,就会在特定的频率上产生相当显著的地震动放大作用。研究结果表明,夹层放大作用的强度主要与其波速有关,而与密度及品质因素关系不大。研究还发现,这种放大作用的强度受软弱层波速与厚度之间的某种关系制约。这种关系的规律尚待通过进一步的理论分析或大量模拟研究去揭示。 相似文献
19.
Considerable damages during an earthquake (EQ) are the consequence of in situ soil losing its shear strength which is popularly known as liquefaction. A number of methodologies are available to quantify the safety of a site against liquefaction occurrence. Widely accepted recent methodologies follow iterative process making it cumbersome for the field engineer. In the present work, empirical correlations are proposed in accordance with widely accepted methodology, analysing the effect of various parameters such as overburden pressure, fines content (FC), factor of safety (FOS) etc. These proposed correlations are easy to use for the designers and the field engineers to determine the liquefaction potential of a site. Considering data from 207 global sites, proposed correlations are validated by comparing with standard methodology. Three different graphical validations are presented supporting that the results based on the proposed correlations are closely matching with the standard methodology. In case a site is found susceptible to liquefaction, so far no correlations are available to determine the shear strength required to be achieved after ground improvement which will ensure no liquefaction during future EQ. Proposed correlations in this work can also be used easily to determine improved shear strength required for a known FOS, FC and EQ magnitude (M) from ground improvement. Two flowcharts explaining the use of proposed correlations to determine FOS of a site and improvement shear strength required for a liquefied site from ground improvement respectively are developed in this work. Based on the second flowchart, determination of shear strength required from ground improvement are done for 45 random sites out of 207 liquefied sites during worldwide EQ in this work. 相似文献
20.
路南石林喀斯特的形态特征及地质演化 总被引：1，自引：0，他引：1
石林喀期特是喀斯特地貌中的一种极端形式，主要由表面溶良发育，高达３０￣５０ｍ的剑状石峰、石柱组成。同世界其他一些著名的剑状喀期特相比，路南石林喀斯特具有最为复杂的地质演化历史和最为多样的形态。研究表明：自２亿５千万年前早二叠世末期首次出现石牙以来，石林的发育经历了四大演化阶段；石林的形成是有利的地质、水文、气候条件综合作用的结果，而土下溶蚀是主要形成机理。剑状、峰状、塔状、蘑茹状及其他不规则状为石 相似文献