大气作用下膨胀土填方边坡现场模型试验研究  

Study on the field model test of expansive soil fill slope under atmospheric influence

作　　者：赵金刚[1] 王家鼎[1] 谷天峰[1] 夏蒙[1] 

机构地区：[1]西北大学地质学系/大陆动力学重点实验室,陕西西安710069

出　　处：《西北大学学报（自然科学版）》2013年第6期939-946,共8页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(40972193);高等学校博士学科点专项科研基金资助项目(20116101130001)

摘　　要：在陕西省安康市膨胀土地区建立了填方边坡的现场模型监测系统,采用土壤水分探测器、温度传感器、土压力盒及霍尔式位移传感器等,依据安康实际的天气条件,跟踪测试了静置期、降雨期及积水期3个阶段膨胀土填方边坡的演化规律。研究后认为:①降雨及积水是影响膨胀土含水量最直接的因素,而日照及阴天通过蒸发作用影响土体的含水量,属于间接影响因素。②大气温度是影响土体温度的直接因素,越靠近坡面,土体温度变化幅度越大;土体温度变化存在滞后性,深度越大,滞后越明显。表层土体的湿化则表现为降低温度的影响范围和变化幅度。③对于填方边坡而言,在降雨作用下,坡顶主要表现为竖直向的胀缩变形;坡面则以水平向的累积变形为主。在积水作用下,坡顶存在一个临界深度,在此深度以上,土体膨胀变形占主导作用,向上发生膨胀,在此深度以下则以土体沉降变形为主。④由于土体在降雨初期受冲刷的影响较大,土压力明显衰减,降雨后期的雨水入渗量大于冲刷量,土压力呈上升趋势;随着降雨量的增大、持时加长,土压力受影响的范围及幅度增大。A Province. A monitoring system of fill slope field model was built in the expansive soil area of Ankang City, Shaanxi ccording to the actual weather condition of Ankang City, soil moisture detectors, temperature sensors, soil pressure boxes and hall displacement sensors are used to track and test the evolution of expansive soil fill slope during the stationary period, flush period, and waterlogging period. The results show： ① Rainfall and waterlogging are the most direct factors affecting expansive soil moisture; sunshine and cloudy weather affects soil moisture through evaporation, belonging to the indirect factors. ② Atmospheric temperature is the direct factor affects the soil temperature, the closer to the slope, the greater the soil temperature variations; changes in soil temperature lags, the greater the depth, the more obvious the lag. The humidification of topsoil is performed as reducing the in- fluence range and variations of temperature. ③ For the fill slope, the influence of rainfall on slope top is mainly vertical expansion and shrinkage deformation, while that on slope surface is mainly horizontal cumulative deforma- tion; under the action of waterlogging, there is a critical depth at the slope top, above this depth, soil swelling de- formation is dominant, below the critical depth, settlement deformation is given priority to. ④ Earth pressure was significantly attenuated at the beginning of rainfall due to the influence of erosion. Latter infiltration is greater thanthe erosion volume, so earth pressure shows rising trend. With the increase of rainfall and the longer of duration, earth pressure affects scope and amplitude increases.

关 键 词：膨胀土 填方边坡 大气作用 变形破坏 模型试验 

分 类 号：P642.13[天文地球—工程地质学] P642.22[天文地球—地质矿产勘探]