膨胀土地区边坡活动带深度确定的吸力法  

Depth of Active Zone of Expansive Clay Slope

作　　者：潘宗俊[1] 谢永利[1] 杨晓华[1] 徐伟[1] 

机构地区：[1]长安大学特殊地区公路工程教育部重点实验室,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2006年第3期10-13,共4页Journal of Chang’an University(Natural Science Edition)

基　　金：陕西省交通科技项目(2004E16)

摘　　要：应用Mitchell原理把吸力作为深度的函数，分别在西安一汉中高速公路南郑段K86＋060、K91＋110两处膨胀土边坡的坡顶和坡脚现场开挖观测井，利用张力计进行不同深度处吸力值的现场量测，确定两边坡最大吸力值和影响深度下的平衡吸力值；然后采用原状膨胀土进行水平土柱入渗试验，计算得到土体扩散率。根据以上量测和计算的参数确定大气影响深度，最后通过建立膨胀土边坡破坏模型方程，确定浅表层破坏深度。结果表明：两路堑边坡膨胀土吸力最大值均介于70～80kPa，膨胀土的活动带深度介于1．71～1．74m；浅表层破坏发生在活动带范围之内，其可能破坏深度为1．59～1．72m，二者深度十分接近，表明活动带深度以下的膨胀土层基本处于稳定状态，不受气候条件的影响。According to the principle of Mitchell, which expresses the function relationship between depth and suction, this paper researched expansive soil slope at Nanzheng area in Shaanxi Province along Xi＇an Hanzhong freeway. Through excavating observation wells on top and feet of slope on road cutting in K86＋060 and K91＋110, the suction values of different depths were measured by tensiometer, and the highest suction value and equilibrium soil suction of active zone depth were attained. Then the original expansive soils were tested in horizontal infiltrative experiments of soil column to attain diffusion coefficient of expansive soil. According to the Mithchell Formulation, the active zone depth was calculated. Finally through founding equation of expansive soil slope, the collapse depth of surface layer was gained. The results show that all the high est suction values of expansive soils of slope are between 70 kPa and 80 kPa. The active zone depth of expansive soils is between 1.71 m and 1.74 m. The collapse of surface layer occurs in active zone depth, and possible collapse depth is between 1.59 m and 1.72 m. Both depths are very close, which illustrate that expansive soil layer under the depth of active zone is stable. 3 tabs, 3 figs, 8 refs.

关 键 词：道路工程 膨胀土 吸力 扩散率 活动带深度 

分 类 号：U416.167[交通运输工程—道路与铁道工程]