风化砂岩石窟表面热响应及力学性能变化:对砂岩石窟本体表层风化(劣化)评价的启示

表层风化问题严重影响石窟寺类文物的长久保存。如何通过风化表层的性能变化来对石窟寺进行病害诊断和风险评估是预防性保护的关键问题。本研究利用便携式无损检测手段(ProceqEquotip 550里氏硬度计、FLIR T660红外热成像仪)对甘肃庆阳北石窟寺外立面8个研究面进行表面硬度测试及表面温度监测,分析其典型风化病害的热响应情况及力学性能变化规律。研究结果显示,病害类型对其表面硬度值和温度波动幅度有不同程度的方向性影响。水锈结壳的表面昼夜温度波动幅度最小,表面硬度离散地分布在较高水平;粉化剥落和泛盐的表面昼夜温度波动较平缓,表面硬度值集中分布在较低水平;沟槽状溶蚀(差异风化)的表面昼夜温度波动幅度略高于粉化剥落表面,其表面硬度集中分布在较高水平;微生物覆盖的表层,昼夜温度波动幅度最大,表面硬度值离散地分布在较低水平。上述病害-性能对应关系有助于在石窟寺类文物的日常监测中判别风化病害的分布及变化趋势,对砂岩石窟的风险预警有一定指示作用。     

Evaluation of treated and un-treated Nubia Sandstone using ultrasonic as a non-destructive technique

Deterioration factors, both “exogenous” and “endogenous”, are major sources of damaging monumental stones in Egypt. In the current study, the change state of one of the major Egyptian stones (Nubia Sandstone) is investigated and evaluated before and after consolidation by the use of wave velocity as a new method for detecting its elasticity modulus. Wave velocity propagation (Vp) is one of the most important and effective methods for estimating the durability of monumental stones without using any other harmful method as a compressive strength. This technique is usually used for a number of purposes, the first of which is the qualification of masonry building through its morphology and detection of internal defects (e.g. voids and cracks). The second is the examination of the changes of material physical properties, and the control conservation procedures. Third, it is used with some samples of Nubia sandstone for a laboratory test. The study concludes that the durability of samples increases due to the increase of material compacting as a direct result of using consolidant materials. Using the Vp as a non-destructive technique in examining monumental materials gives the same results of other harmful techniques.     

Weathering of rock art at two sites in the KwaZulu-Natal Drakensberg,southern Africa

Sediments of the Karoo Basin in southern Africa represent one of the world's finest laboratories for investigating sandstone weathering. The natural breakdown of these sandstones, most notably in the Clarens Formation, is destroying much of the indigenous rock art heritage that exists there. In an attempt to elucidate the operative weathering processes, a range of micro-climatic, rock temperature, rock moisture, rock chemistry, and rock property data have been monitored over a 15 year period at two sites in the KwaZulu-Natal Drakensberg. Results suggest that rock moisture regimes and to a lesser extent, rock thermal regimes exert the most damaging influence on San paintings. It is argued that granular disintegration and the enlargement of existing sandstone pores and bedding planes close to the rock surface, facilitate an increasingly dynamic moisture regime, which leads to an accelerating rate of weathering. Recent technological advances in data collection suggest that a re-evaluation of environmental controls may be necessary before weathering, at a scale appropriate to the deterioration of rock art, can be fully understood. The continued existence of indigenous rock art in southern Africa depends on investigations aimed at the development of techniques for its preservation.     

Consideration on the construction process and the sandstone quarries during the Angkor period based on the magnetic susceptibility

Detailed magnetic susceptibility measurement was conducted on the sandstones used for the Angkor monuments constructed in the period spanning the Preah Ko and Angkor Wat styles, and the construction process of the buildings and quarries of the sandstones was considered. Combined with the previous study on the sandstones of the Bayon style [Uchida, E., Cunin, O., Shimoda, I., Suda, C., Nakagawa, T., 2003. The construction process of the Angkor monuments elucidated by the magnetic susceptibility of sandstone, Archaeometry 45, 221–232], the magnetic susceptibility measurement revealed that there were 7 sandstone quarries corresponding to Stages I, II, III, IVa, V, VII and VIIIb during the Angkor period. The sandstones used for the monuments belonging to Stage I show average magnetic susceptibility values ranging from 1.1 to 2.3 × 10⁻³ SI units. In the Bakheng style period (Stage II), the average magnetic susceptibility of the supplied sandstones decreased gradually from around 10 to 1 × 10⁻³ SI units over time. The magnetic susceptibility range of the sandstones used for the monuments of Stage III was from 2.3 to 3.0 × 10⁻³ SI units. In the early Angkor Wat style period (IVb), the average magnetic susceptibility of the supplied sandstones increased over time, reflecting the supply of the sandstones from two different quarries, that is, the quarry corresponding to the Khleang and Baphuon style monuments (Stage IVa), with low average magnetic susceptibilities of 1.1 to 2.4 × 10⁻³ SI units, and the quarry corresponding to the main Angkor Wat style monuments (Stage V), with high average magnetic susceptibilities ranging from 2.8 to more than 4.3 × 10⁻³ SI units. The sandstones of Stage VII show low average magnetic susceptibility around 1 × 10⁻³ SI unit. The sandstones of Stage VId is a mixture of sandstones of Stages V and those of Stage VII. The sandstones with high magnetic susceptibilities are found in the monuments belonging to Stage VIIIb, reflecting the supply from the new sandstone quarry.     

河南渑池石佛寺石窟调查

渑池石佛寺石窟位于豫西地区渑池县坡头乡庙下村,一般认为开凿于北齐时期,通过对石窟造像的艺术分析,以及对石窟所存的明代碑刻的分析,本文认为当开凿于北周,属河南境内唯一的一处北周时期开凿的石窟。     

南京栖霞山千佛岩石窟的测绘与编号

本文是南京栖霞山千佛岩石窟科学考察成果的第一部分。作者对千佛岩石窟进行了精确的地形测量,结合洞窟形制与窟檐的测绘、佛像的调查对洞窟进行了分区与编号,并对石窟造像的现状进行了综述。     

孟津谢家庄石窟开凿时间及艺术分析

孟津谢家庄石窟开凿于西魏大统三年,为洛阳地区最早的西魏石窟造像.其造像艺术手法带有鲜明的民间造像特点,表现出大胆浪漫的情调,具有十分重要的价值.     

龙门石窟的彩绘装饰

龙门石窟在开凿时利用丰富多彩的彩绘颜料对窟龛和造像进行了装饰,本文通过对龙门石窟现存彩绘装饰的调查和研究,初步总结了龙门石窟彩绘装饰的一些特征和规律,并就龙门石窟彩绘装饰的时代和成分等的进一步研究提出了建议。