西北地区古代生土建筑物冻融风蚀机理的实验研究

An Experimental Study on the Mechanisms of Freeze-thaw and Wind Erosion of Ancient Adobe Construction in Northwest China

西北地区独特的旱寒条件 ,一方面使古代生土建筑物得以建筑和保存 ,另一方面 ,强烈的冻融风蚀作用致使许多生土建筑坍塌殆尽 ,导致这一不可再生资源的破坏 .通过对古代生土建筑物冻融风蚀的模拟实验 ,研究发现 ,冻融风蚀是古代生土建筑物毁坏的主要因素 .当冻融次数相同 ,随含水量增加 ,风蚀强度增大 ,尤其是当含水量相同条件下 ,随冻融次数的增加 ,风蚀量显著增大 .因此 ,反复冻融循环作用所引起的土体微结构破坏是古代生土建筑物毁坏的主要原因 ,而风蚀又是其主要动力机制 .风洞模拟实验结果表明 ,5 %LS和 10 %PS耐冻材料具有良好的抗蚀性 ,因此 ,在自然条件严酷的西北地区 。

There are many ruins of ancient adobe constructions in Northwest China, such as the famous ancient Great Wall built in the Ming and Han Dynasties in Hexi Corridor, the Changhe and Gaochang Ancient Cites in Xinjiang Region, and so on. All of these constructions are precious mankind s cultural heritage, and their valuable artistic value is rare worldwide. Due to the unique natural conditions, under cold and dry climate, the ancient adobe constructions could be constructed and preserved in Northwest China, meanwhile, the violent processes of the freeze-thaw and wind erosion caused many ancient adobe constructions collapsed, resulting in destruction of these unrecoverable resources. Limited by various factors, few studies about mechanisms of the freeze-thaw and wind erosion of ancient adobe constructions have been conducted before. Recently, numerous research works about the mechanisms and protection of them have been done. However, the study about the coupling mechanism between freeze-thaw and wind erosion is seldom. By simulated experiment on the freeze-thaw and wind erosion of the ancient adobe constructions, this paper conclude that the freeze-thaw and wind erosion is the primary cause of the destruction of many ancient adobe constructions. If the frequency of the freeze-thaw cycle is invariant, the wind erosion intensity will increase with the increasing of the water content in earth. Similarly, if the water content in earth keeps invariant, the wind erosion intensity will increase distinctly with the increasing of freeze-thaw times. Based on these findings, the authors conclude that the destruction of the microstructure in earth resulted from the process of the freezing-thawing cycle is the major cause of the destruction of ancient adobe construction. According to the result of wind tunnel experiment, the earth sample reinforced with 5% of LS and 15 % of PS is a bear for wind erosion. So this reinforced method could be effective in protecting the rare ancient adobe constructions from rigorous natural conditions in Northwest China.