土工袋砌护农田排水沟道边坡稳定性分析

STABILITY ANALYSIS OF ARGO-DRAINAGE DITCH SLOPE PROTECTED WITH GEOTEXTILE SOIL CONTAINERS

针对宁夏引黄灌区农业灌排工程中排水沟道边坡滑移问题,尝试采用土工袋装新技术砌护农田排水沟道。文中推导了基于土工袋砌护农田排水沟边坡的扩展简化Bishop公式并编写相应计算程序,分别对均质土边坡、土工袋砌护边坡以及考虑流沙地层条件时的均质土边坡和土工袋砌护边坡4种模式进行了稳定性分析。将程序计算结果及其搜索的滑移面位置分别与岩土工程专业数值分析软件Geo Studio2007的计算结果和土工袋砌护沟道示范工程的原位监测结果进行对比,结果显示:(1)相同模式下,自编程序计算结果与Geo Studio2007计算结果比较吻合,说明自编程序计算结果可靠;(2)土工袋砌护形式能使均质土坡的安全系数提高34. 5%左右,但对于沟底存在流沙层的情况,仅靠土工袋加固,效果并不明显,建议采用土工袋与抗滑柳桩组合防护形式;(3)原位监测数据表明,土工袋砌护的边坡内部位移量随着深度的增加而增大,其规律与自编程序搜索的滑移面位置趋势基本一致;(4)土工袋砌护边坡的内部位移量、位移年变化量等均小于传统的草土柳桩支档边坡,边坡稳定性较高。

A new geotextile technique is proposed to solve the slip problem of drainage channel in irrigation area of Ningxia Yellow River diversion. This new form of masonry protection is first attempted in the Ningxia region. This paper examines the effect of this kind of masonry. In this paper,the extended simplified Bishop formula under the condition of geotextile masonry protection is derived. The MATLAB calculation program is compiled according to this formula. According to the program,the four working conditions of farmland drainage channel are calculated.The four conditions are homogeneous soil slope, geotextile protection slope, homogeneous soil slope when considering quicksand layer and geotextile protecting slope when considering quicksand layer. The results of program calculation and the position of slip plane searched by program are compared with the results of geotechnical engineering software GeoStudio2007 and the actual prototype monitoring results. Finally,we come to the following conclusions.(1) The result of self-programmed program is in good agreement with that of GeoStudio2007 in the same mode,which shows that the result of self-programmed program is reliable.(2) The stability of homogeneous soil slope can be improved by about 33%in the form of geotechnical bag,but the effect is not obvious when there is quicksand layer in the bottom of the trench. It is suggested that the combination of geotextile and anti-slide pile should be adopted.(3) Field monitoring data show that the internal displacement of geotextile masonry slope increases with the increase of depth,which is basically consistent with the trend of slip plane position searched by the self-compiled program.(4) The internal displacement and annual displacement of geotextile masonry slope are smaller than those of traditional grass soil willow pile slope and the stability of the slope is high.