北石窟寺岩体渗漏现状分析研究

北石窟寺是陇东地区一处规模最大的佛教寺院文化遗存,距今已有1500多年的历史,现为全国重点文物保护单位。由于长年雨水的冲刷浸蚀崖面岩体,造成崖壁渗水、漏水,对石窟文物造成严重危害。北石窟寺保护面临的主要问题：石窟崖壁渗水;崖体裂隙与危岩、危石的治理;窟龛潮湿,酥碱等病害滋生;石窟文物风化日趋严重。     

杭州烟霞洞造像大气降水与洞窟渗水关系调查研究

杭州烟霞洞山体岩石主要由碳酸盐岩构成,文物保护区内山体形成相对发育的岩溶微地貌,地形环境较复杂。由于洞窟岩体溶蚀作用及存在大量的构造裂隙,洞窟内常年渗水。大气降水及山体内地下水沿着各种裂隙及溶洞渗流进入洞窟内,致使佛像表面产生钙华沉积、溶蚀等病害,严重影响石刻造像的长期保存。通过对烟霞洞山体的地质调查、造像洞窟内渗水裂隙调查、渗水点与降水监测结果分析,研究得出烟霞洞内渗水点的渗流路径及与大气降雨的关系,从而为制定相应的切实可行的渗水治理措施提供技术依据。     

龙门唐代密宗造像

龙门石窟保存一批唐代密宗造像,过去没有引起足够的重视。现集中报道如下。一、密宗造像 1.擂鼓台南洞的大日如来现置龙门擂鼓台南洞内的大日如来像,据调查是清末由龙门某寺院迁来的。从风格看应为武则天后期作品。像高2.15米,结跏趺坐于须弥座上,座高o.86米。像螺髻,戴宝冠,上饰莲花及忍冬流云。面略长,较平,眉梢、眼角上斜。左手平伸五指仰置右足上;右臂戴葫芦形臂钏,掌心向下抚右膝。     

Discussion on the variation characteristics of water content of Quaternary soil cover on the top of Yungang Grottoes and the problem of water seepage in caves北大核心

为研究云冈石窟顶部土壤覆盖层的含水率变化情况,建设了土壤环境监测网收集云冈石窟土壤含水率实时监测数据,并分析其时空变化特征及影响因素。结果表明,平坦地形条件下云冈石窟顶部第四纪土壤覆盖层含水率时空变化特征明显:年变化具有周期性,垂向上随深度逐层降低(冬季除外)。春、夏季土壤含水率抬升、储水,秋、冬季下降、失水;在春、夏日土壤含水率呈白天上升、夜晚下降趋势,秋、冬日则呈白天下降、夜晚也下降趋势。土壤含水率时刻处于不停的运动变化之中,受温度、大气降水、微地形等众多因素影响,山体边坡浅层土壤可能为侧向饱和流的入渗通道。降雨对土壤含水率的影响深度与实际入渗深度不一致。云冈窟内顶板及岩壁上部、中部含水率主要受降雨渗透窟顶土壤层、沿岩体裂隙通道进入洞窟的渗漏水控制,而岩壁底部含水率更多受窟前不饱带和与地下毛细水的影响。多年的防水实践也证明云冈洞窟渗漏水主要来自于石窟顶部及附近区域。防渗排水始终是云冈洞窟渗漏水治理的主导思路,建议应根据窟顶土壤厚度、地形地貌和遗址分布等分区治理,充分发挥土壤的防渗作用,减少对土壤覆盖层的过度干预。防渗层材料在具有防渗作用的前提下,应具备一定的透气性,满足“洞窟—覆盖层—大气环境”之间的水汽循环。     

地面核磁共振方法在石质文物保护中的应用

石质文物破坏问题不仅在于人为破坏和表面污染,更多来自自然因素对文物的破坏,例如,日晒雨淋、风沙吹蚀、地表水的冲刷、地震、地下水的侵蚀溶蚀。为对第六批全国重点文物保护单位阳华岩摩崖石刻露天石质文物病害进行探查,采用无损探测的地面核磁共振方法和探地雷达方法,直接找水的地面核磁共振方法成功探测出摩崖石刻依附岩体地层含水分布状况。探地雷达方法探测出依附岩山体内岩溶、裂隙的发育状况。两种方法探测结果发现,石刻依附岩体内岩溶、裂隙发育,部分区域岩溶裂隙带已成为地下水汇聚场所或流通通道,对阳华岩摩崖石刻构成了极为严峻的侵蚀威胁。两种方法解释结果互为验证,研究结果为阳华岩摩崖石刻的病害治理和保护提供了宝贵的基础资料。     

云冈石窟五华洞壁画修复保护技术

云冈石窟始建于北魏,以规模宏大、题材丰富、雕刻精美闻名于世,是我国规模较大的古代石窟群之一。五华洞指云冈石窟现编号第9、10、11、12、13五个洞窟,其现存壁画及彩塑均为清代包泥并重装,内涵丰富且色彩绚丽。由于长期受环境因素影响,出现壁画酥碱、地仗层剥离、脱落等病害,再加上窟区近年来湿度和降雨量比较大,壁画局部病害有加重趋势,对现存壁画的长期保存与展示有重大威胁,亟须进行抢救保护。     

中国石窟寺保护性建筑的设计与实践

在龛窟外部修建保护性建筑及设施是中国石窟寺保护的主要方式之一,20世纪50年代后就进行了求索和小范围试验,以敦煌莫高窟加固工程以及龙门奉先寺保护为代表,龙门奉先寺修建保护性建筑的设计方案虽未实施,却基本可以代表当时中国石窟寺保护性建筑工程实践的主要思路。20世纪后半叶,修建保护性建筑并非中国石窟寺保护的首选,保护专家更倾向于采取远观不易察觉的化学保护方法。20~21世纪之交进行了大胆探索,以云冈石窟保护性建筑的设计与实践为代表,这些保护性建筑方案有仿古样式、现代样式和模拟环境样式;有的方案将现代建筑设计中最为前卫的设计理念、软件技术运用到保护性建筑的设计中,提供了很多极具创意的参考;"防水建筑"的设计也极具启发意义。理性科学、综合考虑的设计思路代表了石窟保护性建筑设计未来的发展趋势。     

3D打印技术在龙门石窟金刚经洞修复中的应用

为了缓解龙门石窟金刚经洞因局部坍塌引起的水害、微生物等病害发育问题,利用3D打印技术对坍塌部位进行修复:修复部件以光敏树脂为打印材料,修复部件为空心结构以减轻荷载；对修复部件进行光场、温度场仿真设计,使洞窟内日光辐射强度降低至日光直射的50%~56%,窟内温度分布差值由6.6℃降低到1.9℃；修复部件采用S8801涂覆内外表面,S8801老化实验后主要性能保持率均大于90%,并采用玄武岩纤维与玻璃纤维增强修复部件内表面。经多次降雨后观察,龙门石窟金刚经洞由缺失导致的雨水倒勾等问题得到有效缓解。该工作为3D打印技术与不可移动石质文物修复工作结合奠定基础。     

潼南大佛寺摩崖造像水害治理浅析

水害一直是石窟寺保护中的一个技术难题。从潼南大佛寺摩崖造像区水文气象、地形地貌及地质结构入手,分析摩崖造像区域受到的主要水害侵蚀。地表水对摩崖造像影响主要为洪峰期洪水淹没造像,冲蚀造像区所在的斜坡坡脚,岩体底部掏蚀悬空缺失支撑,或将岩底泡软,降低岩体承重力,导致岩体形变甚至对摩崖造像造成不可逆性毁坏。大气降水冲蚀造像区岩壁,易形成冲沟,破坏岩壁整体性。渗透水浸湿造像损坏文物,流至岩底,软化岩底,使得岩体失稳。地下水使摩崖造像湿度变大,软化岩体,加速风化,裂隙渗水,造像侵湿、风化脱落,文物受损。长期的水害侵蚀,使摩崖造像遭受水产生的物理危害、化学危害和生物危害等。按照“以排为主、以堵为辅、预防结合、技术助力、持续监测、科学管理、因地制宜、综合防治”的水害防治原则,依据防治不破坏的防治理念归纳出适合潼南大佛寺摩崖造像水害的防治方法。     

河南洛阳龙门石窟潜溪寺岩体构造特征分析研究

为了治理龙门石窟潜溪寺的渗水,保护石窟造像,必须要先摸清岩体构造及渗水通道。本工作采用现场裂隙调查与物理探测相结合的方式对窟区岩体结构构造特征进行了分析研究,在对潜溪寺窟区复杂的岩体结构构造调查分析与现场物理探测实验的基础上,基本摸清了潜溪寺石窟区岩体构造特征和渗水通道。此方面的研究不仅有助于准确认识分析潜溪寺石窟水害的形成机理,对潜溪寺石窟水害的治理及其它类似石窟的渗水病害研究也具有示范和指导意义。     

南方多雨区域石窟寺防渗效果评价研究——以飞来峰造像二期保护工程为例

南方多雨区域石窟寺的防渗加固是石窟造像保护的重要措施。近年来随着国力的增强,一大批文物保护工程已经实施。但是,对于石窟寺加固保护后效果的跟踪研究却较少。全国重点文物保护单位——杭州飞来峰造像原佛龛裂隙渗水较为严重,已对文物造成破坏和威胁。自2005年以来,飞来峰造像区域已完成了两期保护工程,实施了危岩加固、裂隙灌浆、地表防渗等工程措施。跟踪评价工程的防渗效果,对于后续保护工程和类似石窟造像的保护具有重要参考价值。本研究结合工程资料,实地观察测量渗水情况和分析渗出物成分,试探性对飞来峰造像二期保护工程的防渗效果进行定量化评估。该工作可以为南方多雨区域石窟寺防渗工程的效果评估提供借鉴。     

前视全景钻孔电视在龙门石窟防渗工程中的应用

影响龙门石窟雕刻艺术品长期保存的主要病害是渗水,卸荷裂隙往往切割洞窟、隙宽较大而成为洞窟渗水的主要通道。为查明洞窟卸荷裂隙的分布位置,最可靠的方法是在现场进行水平钻探。但受钻探施工的干扰,钻孔岩芯可能在钻探取芯的过程中造成折断或破裂,钻孔取芯率也会相对较低,因而仅靠观测岩芯难以确定卸荷裂隙的准确部位。为此,采用有潜在价值的钻孔电视方法,以识别不同的岩层,确定裂隙的分布情况及裂隙中的充填物。研究结果表明钻孔电视在龙门石窟防渗工程中取得成功的应用,说明这是一种值得在岩土文物保护工程中推广应用的新技术。     

Nari (calcrete) outcrop contribution to ancient agricultural terraces in the Southern Shephelah,Israel: insights from digital terrain analysis and a geoarchaeological field survey

A field survey revealed that Byzantine and Early Arab (ca. 5th to 8th century C.E.) agricultural systems in the semi-arid region of the Shephelah (central Israel) were similar to runoff agricultural systems in the arid region of the Negev (southern Israel). This similarity led to the hypothesis that systems in the Shephelah also function as runoff farms. This hypothesis is not trivial since runoff values in semi-arid regions are generally low due to intensive but short rainfall events, and due to the presence of sink patches that absorb runoff on slope surface. The aim of the current research is to examine whether runoff potential in a representative agricultural system in the Shephelah is sufficient for sustaining runoff farming. A geoarchaeological field survey and digital terrain analysis show that large Nari (calcrete) outcrops on the footslopes generate high runoff values that improve water potential. Hydrological simulations and calculations show that 230 mm of direct rainfall generates a water potential equivalent to 300 mm of direct rainfall. In view of these results, it is reasonable to conclude that the presence of Nari enabled runoff agricultural farming in the Shephelah region, even in drought years.     

重庆大足石刻千手观音造像区地下水渗流机制分析

为研究渗水病害在重庆大足宝顶山千手观音本体修复加固工程中产生的影响,通过现场调查、钻探和钻孔压水实验,分析研究岩体透水性和地下水渗流机制。结果表明,千手观音造像区后部崖体完整性较好,没有渗水构造裂隙存在,不受地下水的影响。     

‘Torrents of Terror’: the August 1998 Storm and the Magnitude,Frequency and Impact of Major Floods in the Illawarra Region of New South Wales

The Illawarra Region some 80 kilometres south of Sydney is characterised by a prominent coastal escarpment that rises to 700 m within 12 km of the coast and forms a locus for frequent, high intensity rainfall events. One of the most recent recorded events occurred on 17 August 1998 with rainfall intensities at several pluviometers exceeding 120 mm hr^‐1 over a duration of one hour, with up to 249 mm falling in 3.5 hours during the main storm burst. Detailed pluviometer data indicate that the storm was non‐stationary and moved down catchment producing a widespread zone of 120 mm hr^‐1 intensity rainfall over a 30 minute duration across mid‐lower catchment areas after similar intensity but longer duration rainfall in catchment headwaters. Slope‐area reconstructions of peak discharge indicate that small catchments on the escarpment within the zone of maximum intensity experienced close to 100% rainfall‐runoff relationships, with peak discharges correlated to short duration (<1 hr) peak rainfall intensities. Widespread erosion occurred particularly where urban development had encroached on natural water courses. Debris/hyperconcentrated flows originating from both anthropogenic and natural sediment sources caused damage to urban areas. This paper provides an overview of the spatial and temporal characteristics of the 17 August 1998 storm, the hydrologic and geomorphic response of the streams, and the nature of damage to urban areas. It reassesses the frequency of recent high‐magnitude rainfall/flood events in the region, discussing the relationships between rainfall intensities, estimates of flood magnitudes and stormwater channel capacities.     

Establishing Stage‐Discharge Relationships in Multiple‐Channelled,Ephemeral Rivers: a Case Study of the Diamantina River,Australia

The method for deriving a stage‐discharge relationship has a significant impact on the shape of the river's rating curve. We compare rating curves for a single gauging station on a mutiple‐channelled river in Australia compiled using three different methods – the Urban Runoff and Basin Systems (URBS) rainfall‐runoff model, an empirically‐based velocity‐area method, and the predictive Hydrologic Engineering Centre‐River Analysis System (HEC‐RAS) computer model. The rainfall‐runoff model was found to predict lower discharges for stage heights over 3.5 m than both the empirically‐based velocity‐area method and the HEC‐RAS model. The empirically‐based velocity‐area model predicts similar discharges to the rainfall‐runoff model for stage heights less than 3 m but much higher discharges for larger flood events. The HEC‐RAS model predicts higher discharges than both other rating curves at all stage heights probably due to under‐estimation of the impact of surface roughness on flow velocity. The three models are discussed with particular reference to their use on multiple‐channelled rivers.     

A Physical-Geographic Regionalization of the Democratic Republic of Vietnam

The author served as a consultant in 1963–64 with a geography group of the State Committee of Sciences of North Vietnam that compiled a physical regionalization of the country. The regionalization, at 1:1,000,000 to 1:2,000,000, was based mainly on geologic-geomorphic and climatic criteria as well as other, more variable components of the physical environment. Six natural oblasts were distinguished: (1) the Northeast hills and low mountains, with a relatively cool climate, (2) the Northwest, distinguished by linear mountain ranges trending NW—SE, (3) the Truong Son, or Annamese Cordillera, (4) the Bac Bo [Tonkin] plain, the population center and economic core of North Vietnam, (5) the Thanh-Nghe coastal plains, and (6) the Binh-Tri-Thien coastal plains, in the extreme south. The oblasts were further partitioned into suboblasts, 51 rayons and 50 subrayons.     

Prehistoric land use and hydrology: a multi-scalar spatial analysis in central Arizona

Human land-use strategies involving the management of rainfall and runoff to promote crop production are found throughout the world. This paper presents a functional assessment using hydrological modeling with modern high-resolution LiDAR datasets and contextual archaeological site data to study prehistoric agriculture. The focus is on rock alignments created by the Hohokam culture in the semi-arid environment of the US Southwest. By incorporating a multi-scalar GIS study for terrain analysis at a regional, community, and site scale, the complex interactions between the prehistoric sites, features and the environment are revealed. The results of these analyses on digital elevation models (DEMs) gave insight to the past functionality of such agricultural features within the cultivated landscapes. The results included:1) The agricultural features were suitably placed for the collection of rainfall and runoff.2) The features were reducing the volume of water flowing through the area to prevent flooding and crop destruction and promoting soil infiltration.This shows the complexity and innovation of prehistoric societies living in marginal environments and how their adaptation to such environments was necessary to sustain their populations.