定义因降雨作用,坡体在降雨结束之后出现最不稳定状态(或滑坡)的现象为迟滞现象.根据雨水在土体中的入渗规律,给出2类降雨作用边坡的雨水入渗模型,以说明降雨触发边坡失稳迟滞现象的发生机理.定义临界时间概念.基于渗流-坡体稳定性耦合分析方法,采用数值分析手段研究迟滞现象与坡体土质参数的关联性.研究结果表明:迟滞现象与土体的渗透参数和强度参数均有关联;当渗透系数ks大于1×10-4 m/s,且进气排水能力较强时,土质坡体倾向于在降雨过程中失稳,当ks在1×10-7～1×10-6 m/s范围内取值时,坡体的临界时间通常在降雨结束后取得;当土体强度参数一定时,随土体渗透能力增强,坡体的临界时间呈现出不断减小并最终趋于平缓的变化趋势;当土体渗透性一定时,随着土体强度参数增大,坡体的临界时间呈现出不断增大并最终趋于平缓的变化趋势;土体渗透性对迟滞现象的产生有主导作用,在满足渗透性条件下,土体强度参数对迟滞现象产生的影响在土体强度较低时起主导作用.%The effect of rainfall on the slope may continue and the most unstable state may occur after rainfall stops. This phenomenon was described as the delay phenomenon. According to the infiltration characteristics of rainwater in the soil, two representative models of landslides occurring after rainfall were set up to illustrate the mechanisms of the delay phenomenon. The concept of critical moment was defined. The relationship between the delay phenomenon and soil parameters was analyzed using numerical analysis method. The results show that the delay phenomenon has a direct relationship with soil permeability parameters and soil strength parameters. The soil slope tends to have failure during rainfall when the permeability coefficient is larger than 1×10-4 m/s and air intake and discharge capacity are strong. The slope tends to be in the most unstable state when the permeability coefficient is between 1×10-7 m/s to 1×10-6 m/s. When the soil strength parameters are determined, the critical moment of the slope decreases firstly and eventually becomes stable with the increase of the permeability coefficient. The critical moment of the slope increases firstly and tends to be stable with the increase of the soil strength parameters when the permeability coefficient is determined. Soil permeability is the major influencing factor of the delay phenomenon. When permeability is fitted, soil strength parameters have dominant efficient when the soil strength is low.
展开▼
