毛细水干湿循环对土遗址风化影响的试验研究

Research on the Impact of Drying and Wetting Cycle of Capillary Water on Weathering of Soil Sites

地下水位的波动引起毛细水对上部遗址体的反复作用,导致遗址体处于干湿循环交替的状态中,从而致使土遗址不断经受反复的湿胀干缩变化,使得遗址体内部发育大量的裂隙,内部结构变疏松,对遗址体造成极大的破坏,最终使遗址体抵抗外界侵蚀的能力下降,加速了土遗址的风化劣变。采用西安地区凤栖塬黄土模拟遗址原址土样进行室内干湿循环模拟试验,研究了在毛细水作用下经过多次干湿循环后,土样的外观形貌、无侧限抗压强度、抗水崩解性、微观结构的变化以及抗压强度随含水率的变化规律,结果表明:随着干湿循环次数的增加,土样的裂隙不断加以发育并相互贯通、无侧限抗压强度逐渐下降、崩解速度整体上呈现出上升的趋势、土颗粒粒径变小且空隙间距变大。

The repeated impact of capillary water on the upper soil sites caused by fluctuation of groundwater table, leading the soil sites to be in a condition of wetting and drying cycles, thus the soil sites withstand constantly the repeated swelling shrinkage changes, resulting in a large number of cracks developed within soil sites, the internal structure become much looser, causing great destruction of the soil sites, and ultimately making soil sites to have weaker resistance to external corrosion, accelerating weathering of the soil sites. Using Loess of Fengqi Plateau in Xi ＇ an to simulate soil samples of soil sites for indoor drying and wetting cycles experiment, having studied changes of the soil samples＇ appearance of the morphology, unconfined compressive strength, ability to resist water disintegration, micro-structural, and relation curve between unconfined compressive strength and water content,after repeated drying and wetting cycles based on effect of capillary water. The research results show that with the increase of the number of drying and wetting cycles, the soil samples＇ fissures continuously develop and interconnect, unconfined compressive strength gradually decrease, disintegration speed show an increased trend of the overall rate, the particle size becomes smaller and gap turns into bigger.