文章摘要
鲜丹,杨仲康.不同含水率条件下非饱和边坡的稳定性[J].水土保持通报,2018,38(3):123~129
不同含水率条件下非饱和边坡的稳定性
Stability of Unsaturated Slope Under Different Initial Water Contents
投稿时间:2017-11-21  修订日期:2018-12-25
DOI:10.13961/j.cnki.stbctb.2018.03.020
中文关键词: 降雨型滑坡  初始含水率  数值模型  入渗作用机制  天水市
英文关键词: rain-induced landslide  initial moisture content  numerical model  infiltration mechanism  Tianshui City
基金项目:国家自然科学基金国际合作项目“基于干涉测量和物联网技术的甘肃省南部地质灾害监测预警”(2013DFE23030);甘肃省民生科技计划项目(1503FCME006);中央高校基本科研业务费专项资金(lzujbky-2017-208)
作者单位
鲜丹 西北大学 城市与环境学院, 陕西 西安 710100 
杨仲康 兰州大学 资源环境学院, 甘肃 兰州 730000 
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中文摘要:
      [目的]试图改进现有初始条件考量方法,重点分析不同初始含水率条件下降雨入渗对边坡稳定性的作用机制,为滑坡预警提供参考。[方法]以甘肃省天水市廖集村滑坡为例,基于无前期降雨和有前期降雨作用下实测土层含水率结果,将其分别定义为天然和湿润状态,作为初始条件建立渗流与应力的流-固耦合物理力学模型。[结果]天然状态下,非饱和入渗迅速,但入渗仅局限于浅表层1-2 m,稳定系数在入渗初期显著下降,但随着下渗的停滞而缓慢变化,往往形成浅表层滑坡;湿润条件下,土体持水缓慢,但能下渗到3-4 m以下的较深部位,随着入渗深度的增大,土体软化作用加强,形成深部滑坡。所以,土体干燥状态时,进行7 d的雨量预警是有效的防灾方法。对于连阴雨天气,土层较湿润,要注重对滑坡体4 m以下部位孔隙水压力和坡脚位移形变的监测。[结论]土体初始条件对非饱和入渗和稳定性变化过程具有显著影响,是降雨触发型滑坡稳定性分析中不可忽略的因素。
英文摘要:
      [Objective] To improve the existing evaluation methods on initial conditions and understand the mechanism of rainfall infiltration on slope stability, in order to provide effective suggestions for landslide early warning.[Methods] Taking Liaoji landslides in southern of Tianshui City, Gansu Province as a case study, soil was defined as a natural or wet state based on whether there was a antecedent rain. The Boltzman model was applied to turn pore water pressure into water content. And the fluid-solid coupling models were established to make a numerical analysis.[Results] In a natural state, soil absorbed the rain rapidly, and infiltration were confined in the superficial layer of 1—2 m. The stability coefficient decreased significantly in the early stage, but slowed down with the stagnation of infiltration, and formed shallow landslides ultimately, similar to plastic sliding. In wet condition, soil held water slowly, but the infiltration reached deeper position(3—4 m) and increased its pore water pressure. As the increase of infiltration depth, the process of soil softening became stronger and stronger and the sliding surface was often occurred in the deep position. When the soil was dry, the 7-day rainfall warming was an effective method for disaster warming. While in the rainy weather, soil kept in wet, and the pore water pressure blow 4 m and the slope displacement should be monitored.[Conclusion] The initial conditions of soil have significant impact on the process of unsaturated seepage and stability changes. Consequently, it is an integrant factor in stability analysis of rain-induced landslides.
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