土质路堑边坡冻融失稳及植被护坡机理研究  

Instability of soil cutting slopes caused by freeze-thaw and reinforcement mechanism by vegetation

作　　者：刘红军[1] 郭颖[2] 单炜[2] 陶夏新[3] 孙玉英[4] 

机构地区：[1]五邑大学,广东江门529020 [2]东北林业大学,黑龙江哈尔滨150040 [3]哈尔滨工业大学,黑龙江哈尔滨150090 [4]黑龙江工程学院,黑龙江哈尔滨150050

出　　处：《岩土工程学报》2011年第8期1197-1203,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50538030);交通部科技项目(200235332310);黑龙江省科技攻关项目(GZ07C401);国际滑坡研究计划项目(IPL-132)

摘　　要：依托同三高速公路扩建工程方正—哈尔滨段路基加宽一侧粉砂质黏土路堑边坡,采用室内三轴实验、现场监测、原位测试等方法,开展了路堑边坡冻融失稳及植被护坡实验研究。三轴实验结果表明:在土体含水率小于最佳含水率时,土体黏聚力随含水率的增加而增大,超过最佳含水率时,黏聚力随含水率增加而减小,在最佳含水率附近达到峰值;土体内摩擦角随含水率的增加而减小。土体黏聚力随冻融循环次数的增加而降低。现场监测结果表明:边坡土体冻结的过程中,水分向冻结锋面迁移;木本护坡植物要比草皮有明显的吸水作用,紫穗槐表现的更加明显。现场直剪实验得出:木本植物根系复合土的抗剪强度比素土的抗剪强度明显增大,在同一坡面相近位置,采用紫穗槐和胡枝子护坡时,其根系复合土的抗剪强度比素土的抗剪强度大2倍左右。理论分析表明:有效地减小坡面荷载,可增加边坡稳定安全系数。Based on the silty clay slope in the expansion project from Fangzheng to Harbin along Tongjiang-Sanya Highway,using triaxial shear tests,field monitoring and in-situ test method,the mechanism of slope instability caused by freeze-thaw and the reinforcement by vegetation are studied.Triaxial test results show that when the soil water content is less than the optimum water content,the soil cohesion increases with the increase of moisture.The soil cohesion decreases with the increase of moisture when the soil water content is larger than the optimum water content.The peak value is near the optimum water content.The internal friction angle of soil decreases with the increases of moisture.Soil cohesion decreases with the increase of times of freeze-thaw cycles.Field monitoring results indicate that during the process of soil freezing,moisture migrates to the frozen zone.The effect of absorbing water of woody plants is more obvious than that of turf,especially for Amorpha.In-situ direct shear tests show that the shear strength of the soil with woody root is larger than that of the soil without root.In the similar location of the same slope,where Amorpha fruticosa and Lespedeza are planted,the shear strength of the soil with woody root is three times that of the soil without root.Theoretical analysis shows that it can effectively reduce the slope loading so as to strengthen the safety factor of slope stability.

关 键 词：路堑边坡 粉砂质黏土 冻融 植物护坡 根系复合土 

分 类 号：U416.1[交通运输工程—道路与铁道工程]