加筋粗粒土坡稳定安全系数的简化计算方法  

A Simplified Method for Calculating Stability Factor of Reinforced Granular Soil Slope

作　　者：胡幼常[1] 陈晓鸣 许爱华 毛爱民 刘杰 

机构地区：[1]武汉理工大学交通学院,湖北武汉430063 [2]中国交通建设股份有限公司,北京100088 [3]新疆维吾尔自治区交通规划勘察设计研究院,新疆乌鲁木齐830006

出　　处：《公路交通科技》2018年第3期16-27,共12页Journal of Highway and Transportation Research and Development

基　　金：新疆维吾尔自治区交通运输厅科技项目(2012-303-5)

摘　　要：为了探寻土工合成材料加筋粗粒土坡稳定性分析的实用方法,将置于坚硬地基上的土工合成材料加筋粗粒土坡按准黏聚力原理转化为等代均质土坡,分别用简化Bishop法计算两者的稳定安全系数F_(sg)和F_(sj),并试图寻找到能反映F_(sg)-F_(sj)关系的数学表达式,以便将复杂的加筋土坡安全系数F_(sg)的计算转化为简单的均质土坡安全系数F_(sj)的计算。为此,对黏聚力c=0,内摩擦角φ=35°,36°,37°,重度γ=18,21,25 kN/m^3,边坡高度H=4~50 m,坡率m=0.5,0.75或1,加筋层间距S=0.3~0.8 m组合出的一系列加筋粗粒土坡分别计算F_(sg)和对应的F_(sj),发现F_(sg)和F_(sj)具有良好的相关性,并且当S在0.3~0.8 m内变化时,F_(sg)-F_(sj)关系曲线与S,H,φ,γ几乎无关,仅与m有关。当F_(sg)=1~2时,经曲线回归分析发现F_(sg)-F_(sj)关系与三次多项式几乎完全吻合,其相关系数达到1。于是,分别得到了坡率m=0.5,0.75,1这3种情况下的加筋粗粒土坡F_(sg)-F_(sj)回归公式,从而实现了以F_(sj)来计算F_(sg)的设想,使计算大为简化。而且,按这些回归公式计算出的F_(sg),其绝对误差和相对误差在F_(sg)=1~2时分别不超过约±0.033和±1.6%,在F_(sg)=1~1.5时则分别不超过约±0.018和±1.2%,满足工程设计的要求。Abstract： In order to find out a practical method for evaluating the stability analysis of geosynthetic- reinforced granular soil （GRGS） slope, a GRGS slope constructed on firm foundation is converted to an equivalent homogeneous soil slope according to the quasi-cohesion principle. Fss, the stability factor of GRGS slope, and Fsj, the stability factor of the said homogeneous slope are calculated respectively using Bishop＇s simplified method, trying to obtain a formula describing Fsg - Fsj relationship so as to replace the complex calculation of Fsg with an easy computation of Fsj. For this purpose, a lot of computations are carried out to determine the F,g and the corresponding F j for a series of GRGS slopes with the soil＇s cohesion of 0. Each GRGS slope varies in the soil＇s internal friction angle of 35°, 36°, 37°, in the soil＇s unit weight of 18, 21, 25 kN/m3, in the slope height from 4 -50 m, in the slope ratio of 0.5, 0.75 or, 1, and in the reinforcement spacing from 0. 3 m to 0. 8 m. It is found that （ 1 ） there is a good correlation between Fsg and Fsj ; （2） if the reinforcement spacing is specified from 0.3 m to 0. 8 m, the Fsg - Fsj curves are hardly effected by reinforcement spacing, slope height, soil＇s internal friction angle, and soil＇s unit weight, except for the slope ratio. Every Fss- Fsg curve is proved by fitting curve analysis agreeing well with a cubic polynomial equation when Fsg = 1 - 2 with the correlation coefficient equal to 1. Thus, the fitting equations for estimating Fsg by Fsj for the GRGS slope with slope ratio of 0.5, 0. 75 and 1 are respectively presented, which leading to a very simple calculation of Fsg. The absolute or relative error of Fsg formulas is not greater than about ± 0. 033 or ± 1.6% respectively when Fsg =- 2,and not greater than about ±0. 018 or ± 1.2% when Fsg = 1 - 1.5, which satisfies the engineering design.

关 键 词：道路工程 安全系数简化公式 回归分析 加筋粗粒土坡 等代均质土坡 

分 类 号：U416.1[交通运输工程—道路与铁道工程]