【摘要】 膨胀土边坡在大气干湿循环与降雨作用下常发生浅层坍滑破坏，而目前对酸雨的化学侵蚀效应对边坡稳定性的影响尚缺乏深入研究。文中基于室内试验获取的酸雨环境下膨胀土物理力学参数，采用FLAC 7.0有限差分软件，依据湿度应力场等效理论，建立考虑酸雨环境(pH值为3、5、7)渗透系数变化及吸湿膨胀效应的膨胀土边坡渗流-热-力耦合数值分析模型，分析不同pH值降雨入渗条件下边坡渗流场、位移场、应力场及安全系数。结果表明，随降雨历时增加，边坡浅表层由非饱和状态转变为饱和状态，饱和区从坡脚向坡顶扩展；酸雨pH值越低，坡体暂态饱和区形成越早，坡脚孔隙水压力越大，坡体水平位移越大，应力集中发展越快；降雨3 d时，pH值为3的酸雨环境下边坡安全系数比pH值为7时下降约9.7%,持续降雨条件下失稳时间提前约0.7 d;酸雨入渗通过增大渗透系数、降低抗剪强度、加剧膨胀变形等加速膨胀土边坡浅层坍滑的发生。更多还原

【Abstract】 Under the combined effects of atmospheric wet-dry cycles and rainfall, expansive soil slopes often experience shallow collapse failures, but there is still a lack of studies on the chemical erosion effects of acid rain on slope stability. Based on physical and mechanical parameters of expansive soil obtained from indoor tests in acid rain conditions, FLAC 7.0 finite difference software was adopted to build a seepage-thermal-mechanical coupling numerical analysis model for expansive soil slopes, with acid rain environments(pH values of 3, 5 and 7), permeability coefficient changes, and hygroscopic swelling effects consid-ered. The seepage fields, displacement fields, stress fields, and safety factors in different pH rainfall infiltration conditions were analyzed. The results indicate that as rainfall duration increases, the shallow layers of the slopes gradually transition from unsaturated to saturated states, with the saturated zone expanding from the toe to the crest. Lower acid rain pH values lead to the earlier formation of transient saturated zones, while higher pore water pressure at the toe brings about greater horizontal displacement of the slopes and faster stress concentration development. After three days of rainfall, the safety factor in acid rain conditions with the pH value of 3 decreases by approximately 9.7% compared to that under the pH value of 7, while the instability time in continuous rainfall conditions advances by about 0.7 days. Acid rain infiltration accelerates the occurrence of shallow collapse failures in expansive soil slopes by increasing permeability coefficients, reducing shear strength, and exacerbating swelling deformation.更多还原