敦煌莫高窟窟前林带防护效应的风洞实验

摘要/Abstract

摘要： 洞窟环境包括窟内的温度、湿度、光照、气流等环境因素的适宜程度，对保护洞窟内的壁画和彩塑是十分重要的。洞窟环境不仅因洞窟所处的位置、大小、型制、有无窟门及窟门形式等而异，而且与窟外整个大环境密切相关。不同风况对洞窟内的气流交换起着重要的作用，也是造成石窟壁画彩塑风沙尘粒沉积、崖面风蚀的主要原因。通过风洞模拟实验，从窟前流场、洞窟环流、崖角形状及其受力等几个方面研究了窟前林带的防护效应和崖角防风蚀机理。结果表明：从控制洞窟水汽因素来讲，窟前以通风结构林带最佳，疏透结构林带次之，紧密结构林带欠佳。控制窟前林带灌溉强度，建立多次、少量的窟前林带灌溉制度，同时，在偏东风条件下尽量减少对窟前林带的灌溉，是控制林带生长和底层洞窟侧渗的重要一环。考虑到促进洞窟自然通风的需求，采用一定疏透度的窟门和采取必要的强迫通风，能够较大改善洞窟的自然通风和环境适宜状况。

关键词: 敦煌莫高窟, 窟前防风林带, 防护效应, 风洞实验

Abstract: The environments of grottos include temperature, humidity, illumination, air flow and other relative factors, which are very important for protecting the fresco and color modeling in the Mogao Grottos. The environments of grottos not only depend on their location, magnitude, type and the condition of cave door, but also on their external environments. Wind regimes play an important role for the exchanging of air flow in the caves. They are also the main reasons of causing sand accumulation for frescos and color modeling and wind erosion for cliff surface. The authors aim to study the sheltering effects of the forestry belts at the front of Mogao Grottos on the basis of airflow field and circulation in the caves, the shapes of cliff angle, and its stress by the use of simulation in wind tunnel. The results show that aeration-type forestry belt is the best form for controlling the water vapor in the caves, sparse-type one is the second, and the compacted-type is the worst. In addition, to control the irrigation intensity for forestry belts and to build an irrigation system of more times and little quantity are supplemental controlling measures. At the same time, irrigation should be limited under east-slanting wind condition. To adopt a given porosity cave door or to enforce aeration can greatly improve the cave environment proper for natural aeration of caves.

Key words: Dunhuang Mogao Grottos, shelter forestry belt, sheltering effect, experiment in wind tunnel

中图分类号:

X169

汪万福;;安黎哲;冯虎元;张伟民;张国彬;李红寿;刘贤万. 敦煌莫高窟窟前林带防护效应的风洞实验[J]. 中国沙漠, 2009, 29(3): 383-390.

WANG Wan-fu;; AN Li-zhe;FENG Hu-yuan;ZHANG Wei-min;ZHANG Guo-bin;LI Hong-shou; LIU Xian-wan. Experiment in Wind Tunnel on the Sheltering Effect of Forest Belts at Front of the Dunhuang Mogao Grottos[J]. JOURNAL OF DESERT RESEARCH, 2009, 29(3): 383-390.

参考文献

[1]段文杰.莫高窟保护工作进入新阶段（代序）[C].敦煌研究文集·石窟保护篇(上).兰州:甘肃人民出版社,1993:1-3.
[2]樊锦诗.敦煌莫高窟的保护与管理[J].敦煌研究,2000, 63(1):1-9.
[3]李最雄.敦煌石窟的保护现状和面临的任务[J].敦煌研究,2000,63(1):10-23.
[4]Agnew N,Lin P M,Li Z X,et al.A lightweight composite panel for repair of cave roofs at the Mogao Grottoes,China[J].Conservation and Management of Archaeological Sites,1999,3(3):135-144.
[5]汪万福,张伟民,李云鹤.敦煌莫高窟的风沙危害与防治研究[J].敦煌研究,2000,63(1):42-48.
[6]Qu J J,Huang N,Dong G R,et al.The role and significance of the Gobi Desert pavement in controlling sand movement on the cliff top near the Dunhuang Magao Grottoes[J].Journal of Arid Environments,2001,48:357-371.
[7]Zhang W M,Wang T,Wang W F,et al.The gobi sand stream and its control over the top surface of the Mogao Grottoes,China[J].Bull Eng Geol Env,2004,63(3):261-269.
[8]Wang W F,Dong Z B,Wang T,et al.The equilibrium gravel coverage of the deflated gobi above the Mogao Grottoes of Dunhuang,China[J].Environ Geol,2006,50(7):1077-1083.
[9]汪万福,王涛,樊锦诗,等.敦煌莫高窟顶尼龙网栅栏防护效应研究[J].中国沙漠,2005,25(5):640-648.
[10]汪万福,李最雄,刘贤万,等.敦煌莫高窟崖顶灌木带防护效应研究[J].中国沙漠,2004,24(3):306-312.
[11]黄翠华,张伟民,李爱敏.莫高窟窟顶风况及输沙势研究[J].中国沙漠,2006,26（3）:394-398.
[12]张克存,屈建军，俎瑞平,等.不同结构的尼龙网和塑料网防沙效应研究[J].中国沙漠,2006,26（4）:483-487.
[13]董治宝,罗万银.风沙床面起动临界受力平衡模型的对比分析[J].中国沙漠,2007,27（3）:356-361.
[14]廖空太,严子柱,常兆丰,等.荒漠绿洲防风固沙林体系的模糊综合评判——以高台县为例[J].中国沙漠,2007,27（6）:1027-1032.
[15]张虎元,张明宋,曾正中,等.敦煌洞窟地层的工程特性[C]. 敦煌研究文集·石窟保护篇(上).兰州:甘肃人民出版社，1993:111-124.
[16]张明泉,王旭东,贾宁,等.敦煌大泉河水环境特征分析[J].兰州大学学报（自然科学版）,2006,42(4):7-10.
[17]王旭东,张明泉,张虎元,等.敦煌莫高窟洞窟围岩的工程特性[J].岩石力学与工程学报,2000,19(6):756-761.
[18]汪万福,王涛,沈志宝,等.敦煌莫高窟大气环境成分的监测分析[J].高原气象,2006,25(1):164-168.
[19]屈建军,张伟民,王旭东.敦煌莫高窟大气降尘的初步观测研究[J].甘肃环境研究与监测,1992,6(3):8-12.
[20]申彦波,沈志宝,杜明远,等.西北地区戈壁和绿洲风蚀起沙(尘)的研究[J].中国环境科学,2004,24(4):390-394.
[21]郑彩霞,秦全胜,汪万福.敦煌莫高窟窟区林地土壤水分的入渗规律[J].敦煌研究,2001,69（3）:172-177.
[22]刘贤万.实验风沙物理与风沙工程学[M].北京:科学出版社,1995:210.