基于影响带观测的加筋土坡稳定性分析

发布时间：2018-03-26 04:26

本文选题：加筋影响带　切入点：土工格栅　出处：《岩土工程学报》2017年02期

【摘要】：为了观测土工格栅加筋影响带的范围,采用特制的一侧透明的拉拔盒,共对6种不同级配的粗粒土分别完成了4种法向压力下的拉拔试验。通过预埋于土中用大头针尖制作并包裹于导线皮中的位移观测点,直接观测了土工格栅在粗粒土中拉拔引起的土粒位移,发现格栅的拉拔会带动其上一定厚度范围内的土体发生移动,这个范围称之为加筋影响带。试验发现平均粒径d_(50)0.83 mm的粗粒土中,土工格栅加筋影响带的厚度δ与试样的法向压力没有关联,主要与土粒级配有关,当d_(50)1.05 mm时,δ随d_(50)的增大有较显著的增加;而当d_(50)1.05 mm后,这种趋势明显减缓;特别是当d_(50)1.65 mm后,二者呈良好的线性递增关系。基于这一试验结果,提出了考虑加筋影响带的加筋土坡稳定性分析方法,简称影响带法。在这一方法中,认为土工格栅的加筋作用相当于增加了加筋影响带内土的黏聚力,而内摩擦角不变。从而将加筋土坡简化为成层土坡,使计算大为简化。而计算得到的加筋土坡稳定安全系数在加筋层距不大于0.6 m,且格栅抗拉强度大于20 k N/m时,与有限元强度折减法的计算结果符合良好。
[Abstract]:In order to observe the influence of geogrid reinforcement, a special one side transparent drawing box is used. A total of 6 different grained coarse grained soils were tested under four normal pressures. The displacement observation points made with large tip of needle and wrapped in the traverse skin were made in the soil. The displacement of soil particles caused by the drawing of geogrid in coarse grained soil is observed directly. It is found that the drawing of geogrid will lead to the movement of soil in a certain thickness range. In the coarse grained soil with average diameter of 0.83 mm, the thickness 未 of the geogrid reinforced zone is not related to the normal pressure of the sample, but mainly to the gradation of the soil. When the number of d / s is 1.05 mm, 未 will increase significantly with the increase of D / D _ (50), but it will slow down obviously when the number of d _ s is 50 ~ 1.05 mm, especially if the number of d _ s is 50 ~ 1.65 mm, there is a good linear increasing relationship between the two. Based on the results of this experiment, In this paper, a method for analyzing the stability of reinforced soil slope considering reinforced influence zone is put forward. In this method, it is considered that the reinforcement of geogrid is equivalent to increasing the cohesive force of soil in the zone. But the angle of internal friction is not changed, so that the reinforced soil slope is simplified as a layered soil slope, and the calculation is greatly simplified. The calculated stability safety factor of the reinforced soil slope is less than 0.6 m and the grid tensile strength is more than 20 KN / m. The calculated results are in good agreement with the finite element strength reduction method.
【作者单位】：武汉理工大学交通学院;新疆维吾尔自治区交通规划勘察设计研究院;
【基金】：新疆维吾尔自治区交通运输厅科技项目(2012-303-5)
【分类号】：TU43

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