西北干旱区土遗址盐渍风蚀效应试验研究

发布时间：2018-08-09 19:28

【摘要】：盐渍风蚀效应是自然界岩土体等多孔介质盐渍劣化加剧风蚀损耗的一种普遍破坏效应,在西北干旱区,这种作用更为明显。地处西北干旱区的土遗址根部富集多种盐分,土体内水分变化时,引起盐分结晶-溶解-重结晶作用,导致土体结构发生劣化,抗风蚀能力随之减弱,经风沙吹蚀后易于在该处形成掏蚀凹进,长期发展则会引起遗址整体失稳而坍塌倾倒,甚至造成毁灭性破坏。因此,对土遗址盐渍风蚀效应展开研究,分析导致其破坏的内在、外在因素,为科学制定具有针对性的有效保护措施提供理论依据。本文在全面认识土遗址赋存环境和遗址土物理力学性质的基础上,对影响土遗址盐渍风蚀效应的盐分、风沙及干湿循环环境等要素开展了室内试验研究。选取甘肃山丹明长城遗址土为试验土样,脱盐后掺入特定含量和类别盐分后制成重塑样,模拟自然干湿循环条件养护并进行声波测试和风洞试验,辅助以土体微结构扫描电镜照片分析,就遗址土盐渍劣化和风蚀损耗效应做出初步分析。试验结果表明,在遗址土盐渍风蚀效应作用过程中,盐分是内在致劣因素,风沙吹蚀是动力机制,而干湿循环为外在助力；不同盐分类别和含盐量对遗址土盐渍劣化和风蚀损耗的影响程度不一,复盐试样结构劣化和风蚀损耗作用最显著,含Na2SO4试样次之,含NaCl试样最小；干湿循环加速土体结构劣化,对盐分析晶较集中的试样表层作用最大,从而使表层的土颗粒更易于被风蚀破坏。
[Abstract]:The wind erosion effect of salinized water is a kind of universal destruction effect which is aggravated by the deterioration of salt in porous media such as rock and soil in nature, and it is more obvious in the arid area of northwest China. Many kinds of salts are enriched in the roots of the soil sites located in the arid region of northwest China. When the soil moisture changes, it causes salt crystallization, dissolution and recrystallization, which leads to the deterioration of soil structure and the weakening of the ability of resisting wind erosion. After the wind sand is blown away, it is easy to form an erosion recess in the site, and the long-term development will cause the whole site to collapse and collapse, and even destroy the site. Therefore, the paper studies the effect of wind erosion on saline soil sites, analyzes the internal and external factors leading to its destruction, and provides a theoretical basis for the scientific formulation of effective protection measures. Based on the comprehensive understanding of the existing environment of earthen sites and the physical and mechanical properties of archaeological soil, this paper has carried out an indoor experimental study on the factors affecting the salinized wind erosion effect of earthen sites, such as wind erosion, wind-sand and dry-wet cycle environment, and so on. The soil of Shandaming the Great Wall site in Gansu Province was selected as the test soil. After desalting and adding specific content and type of salt, the remolded samples were made, and the natural dry and wet circulation conditions were simulated, and acoustic wave test and wind tunnel test were carried out. The effect of soil salinization deterioration and wind erosion loss is analyzed with SEM photos of soil microstructures. The test results show that in the process of salinized wind erosion, salt is an intrinsic factor of deterioration, wind-sand erosion is the dynamic mechanism, and the dry and wet cycle is the external aid. Different salt types and salt content have different effects on soil salinity deterioration and wind erosion loss. The structure deterioration and wind erosion loss of double salt samples are the most significant, followed by Na2SO4 samples and NaCl samples, and accelerated soil structure deterioration by dry and wet cycles. The surface layer of the sample with concentrated salt analysis crystal is the most effective, which makes the soil particles in the surface layer more susceptible to wind erosion.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：K878;P642.13

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