考虑地震荷载的加筋粗粒土坡安全系数简化计算方法  

A Simplified Calculation Method to Evaluate Safety Factor of Reinforced Granular Soil Slope Considering Seismic Load

作　　者：胡幼常[1] 陈晓鸣 毛爱民 刘杰 

机构地区：[1]武汉理工大学交通学院,武汉430063 [2]新疆维吾尔自治区交通规划勘察设计研究院,乌鲁木齐830006

出　　处：《武汉理工大学学报（交通科学与工程版）》2017年第6期943-948,共6页Journal of Wuhan University of Technology（Transportation Science & Engineering）

基　　金：新疆维吾尔自治区交通运输厅科技项目资助(2012-303-5)

摘　　要：加筋土坡的设计计算方法与无加筋的纯土坡相比要复杂许多,不便于一般工程设计人员掌握,在一定程度上阻碍了加筋土坡在工程中的推广应用.为了简化计算,研究了按准黏聚力原理得到的等代均质土坡来计算土工合成材料加筋粗粒土坡安全系数的方法,文中探讨考虑地震荷载时如何按照这种方法计算加筋粗粒土坡的安全系.为此,对置于坚硬地基上的土工合成材料加筋粗粒土坡,考虑地震作用,用简化Bishop法分别计算其稳定安全系数F_(sg)和相应的等代均质土坡安全系数F_(sj).按粘聚力c=0kPa,内摩擦角?=35°~40°,重度γ=18,21,22kN/m^3,边坡高度H=6~50m,加筋层距S=0.3~0.8m,坡率m=0.5,0.75或1组合出的一系列加筋粗粒土坡,取水平地震力系数kh=0.04~0.3内的多个值,分别计算F_(sg)和对应的F_(sj).经回归分析发现,对于c=0kPa,?=35°~40°的加筋粗粒土坡,在F_(sg)=1~2的范围内,F_(sg)和F_(sj)具有良好的相关性,并且可以近似地认为F_(sg)-F_(sj)回归方程与?,γ,H和S无关,也与竖向地震力大小无关,仅与m和kh有关.据此,对m=0.5,0.75,1三种坡率的加筋粗粒土坡分别得出了考虑kh影响的F_(sg)-F_(sj)拟合方程,拟合的安全系数绝对误差一般都小于±0.01,极值不超过±0.03,计算精度满足工程设计要求,从而得出了地震工况下以等代均质土坡安全系数计算加筋粗粒土坡安全系数的简化方法.The design procedure of a reinforced soil slope is more complex than that of a pure soil slope,which is not easy to be mastered by general engineering design personnel.To a certain extent,it hinders the extension and application of reinforced slope in engineering.In order to simplify the calculation,the method of using an equivalent homogeneous soil slope,according to the quasi-cohesion principle,to calculate the safety factor of a Geosynthetic-Reinforced Granular Soil（GRGS）slope is studied.With the simplified Bishop method,the stability factor Fsgof reinforced granular soil slope and the satability factor Fsjof GRGS are calculated and analyzed under seismic load.A lot of numerical examples are completed to determine the Fsgand the corresponding Fsjfor a series of GRGS slopes with the cohesion of c=0 kPa,internal friction angle ？=35°40°,unit weight γ=18,21 or 22 kN/m3,slope height H=650 m,reinforcement spacing S=0.30.8 m,slope ratio m=1∶0.5,1∶0.75 or 1∶1,and horizontal seismic force coefficient kh=0.040.3.A good correlation between Fsgand Fsjwithin the scope of Fsg=12 is demonstrated by the calculated data underkPa and.Moreover,the Fsg-Fsj curves are approximately not affected by internal friction angle,unit weight,slope height,reinforcement spacing,and magnitude of vertical seismic load,and only related to slope ratio and horizontal seismic force coefficient.Based on the mathematical analysis,the fitting equations,including the effect of the coefficient of lateral sersmic load,are respectively suggested for estimating Fsgby Fsjfor the GRGS slope with a slope ratio of 1∶0.5,1∶0.75 or 1∶1.The fitting absolute errors of Fsgare generally not greater than±0.01 and the maximum is less than±0.03,which satisfies the engineering specifications.

关 键 词：加筋粗粒土坡 土工合成材料 地震荷载 稳定安全系数 简化计算公式 

分 类 号：U416[交通运输工程—道路与铁道工程]