合肥新桥机场膨胀土和灰土的水分迁移机理试验分析.docx

转折点不同;初始含水量不同,迁移量与土体初始含水量呈非线性关系。
(5)试验结果对比表明,膨胀土及其石灰改良土混合水水分迁移速度均显著快于气态水;石灰改良土气态水占总水分迁移量比重与初始含水量水平、含水量梯度和迁移时间均有关。
论文研究成果为合肥新桥机场大规模石灰改良膨胀土工程的施工提供了重要理论依据与技术支持。
关键词: 膨胀土 石灰改良膨胀土 水分迁移 气态水 非饱和土 模型试验
Moisture Migration of Expansive Soil and Lime-treated Expansive Clay in the Xinqiao Airport Area of Hefei
Abstract
In semiarid area, expansive clay behaves features of sensitiveness to climate and moisture, and usually leads to unpredicted engineering hazards such as crack, differential settlement, and even causes disasters and huge economic losses for engineering. At present, incorporation lime in expansive clay is widely used to deal with the above problems in engineering practice. However, pany with scale-up of construction, a growing list of engineering problems occurs due to moisture migration for lime-treated expansive clay. This is a big threat to safe operation of critical engineering projects in expansive clay area and deserves much attention from engineers. Therefore, it is of great significance to conduct research on moisture migration mechanism of untreated and lime -treated expansive clay, which will provide a basis for reveal evolution mechanism of engineering behaviors of expansive clay and unsaturated expansive clays.
Basic physical properties and shrinkage-swelling characters of expansive soils and improved soils with lime in Xinqiao international airport project area were analyzed, meanwhile, SEM tests were applied to discuss microstructure for untreated and lime-treated expansive clay. Moreover, test models for mixed water and vaporous water migration were designed to conduct series migration tests of different initial water content, 0%, 6%, 12%, and 24%, respectively. Some main conclusions are reached as follow:
Fissure and micro hole are widely distributed in aggregation for undisturbed expansive clay in engineering area, and the fabric is of big expansion and sensitive to moisture migration from SEM tests. Besides, microstructure of improved expa