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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。
Cave environment, including cave temperature, humidity, light, airflow and other environmental factors appropriate degree of protection of cave paintings and color is very important. Cave environment not only because of the location of the cave, size, type system, with or without cave door and door form, etc., but also with the entire cave is closely related to the entire environment. Different wind conditions play an important role in the exchange of air flow in the caves, which is also the main reason for the dust deposits and the wind erosion on the cliffs of the cave paintings. Through the wind tunnel simulation experiment, the protective effect and the wind erosion mechanism at the cliff front were studied from the front flow field, the circulation of the cave, the shape of the cliff angle and its force. The results show that: From the perspective of controlling the water vapor in the cave, the forest zone with ventilation structure is the best before the cave, followed by the dredging structure forest belt, and the poorly-knit forest structure. Controlling the irrigation intensity in the foreland belt and establishing multiple and small irrigation systems in front of the forest zone meanwhile minimizing the irrigation to the foreland belt under the easterly wind conditions is an important part of controlling the growth of the forest belt and the lateral seepage of the bottom cave. Taking into account the need to promote natural ventilation in the cave, the use of a certain degree of porosity in the door and take the necessary forced ventilation, can greatly improve the natural ventilation of the cave and the environment suitable conditions.