中文摘要：

为了研究含水率对土质覆盖层内部塌陷和整体塌陷2种塌陷模式的影响,基于土拱效应理论,采用结构拱假定和竖向破坏面假定建立考虑含水率变化的非饱和土层塌陷分析模型;推导出内部塌陷的拱形破坏面与含水率关系表达式及判别整体塌陷是否发生的安全系数公式.开展不同含水率黄土trapdoor离心试验,结合已有试验数据对提出的模型加以验证,理论结果与试验数据吻合.计算表明,在所研究的土体含水率范围内,随含水率增加,内部塌陷的破坏面高度增加,而判断整体塌陷发生风险的安全系数则减小,说明含水率增加对土质覆盖层稳定性有不利影响.

英文摘要：

Two approaches were developed for the internal and external failures, respectively, in order toanalyze the influence of water content on failure modes of evapotranspiration cover caused by subsidence.The unsaturated characteristics of the soil in the evapotranspiration cover were involved based on thetheory of soil arching effect. In the two developed approaches, it was assumed that an arch-shape failuresurface is formed above the subsidence in the internal failure mode and two vertical failure planes whichemanating from the sides of the subsidence occur in the external failure mode. The proposed approach forthe internal failure predicts the arch-shape failure surface and that for the external failure proposes a failurecriteria quantified by a safety factor. Centrifugal trapdoor tests for Xi ~an loess were conducted. The testdata, as well as those of Qiantang river silt reported by other researchers, agreed well with the theoreticalresults. In the range of water content of the soils used in this study, the height of the failure surfaceincreases with water content and the risk of the external failure increases as the safety factor decreases withwater content. Increase of water content of the evapotranspiration cover decreases its stability.