纤维加筋土界面渐进性破坏模型  

Modeling of progressive interface failure of fiber reinforced soil

作　　者：张诚成[1] 朱鸿鹄[1,2] 唐朝生[1] 施斌[1] 

机构地区：[1]南京大学地球科学与工程学院,江苏南京210023 [2]南京大学(苏州)高新技术研究院,江苏苏州215123

出　　处：《浙江大学学报（工学版）》2015年第10期1952-1959,共8页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(41302217;41230636);国家"973"重点基础研究发展规划资助项目(2011CB710605);苏州市科技计划资助项目(SYG201213)

摘　　要：为了更深入地揭示解纤维加筋土的破坏机理,研究纤维加筋土中纤维和土体的相互作用机理.提出利用纤维/土体界面切应力-切应变的三参数模型,描述离散纤维在加筋土中的渐进性破坏特性.该模型将单根纤维在加筋土中的拉拔过程分为5个典型阶段,给出各个阶段纤维轴力、位移、界面切应力的解析解.通过单根纤维拉拔试验,验证了该模型的有效性.提出用2个拉拔过渡阶段产生的位移占总位移的比值来评价界面的渐进性破坏特征,对相关的影响因素进行一系列的参数分析.结果表明:纤维的长径比越大或纤维弹性模量与纤维/土体界面剪切刚度比越小,则纤维/土体界面渐进性破坏特征越显著.由该模型得到的纤维/土体界面力学指标可以作为纤维加筋土力学模型的输入参数,通过单独评价土体强度与纤维/土体界面强度来反映纤维加筋土的宏观力学特性.The interaction mechanism between discrete fibers and soil mass in fiber-reinforced soil was investigated in order to better understand the failure mechanism of fiber-reinforced soil.A three-parameter shear stress-strain model of fiber/soil interface was described to predicte the progressive failure of discrete fibers in reinforced soil.The analysis identified five successive phases during the pull-out of a single fiber from soil matrix.Closed-form solutions of the tensile force,displacement and interfacial shear stress were obtained for each of the pull-out phases.The effectiveness of the proposed model was verified by single fiber pull-out test results.The ratio of the displacements generated by two transitional pullout phases to the total displacement was proposed to quantify the significance of the progressive failure of a fiber/soil interface.Results from a series of parametric studies reveal that the progressive failure of the fiber/soil interface becomes more significant with increasing length to diameter ratio or decreasing the ratio of fiber elastic modulus to fiber/soil interface stiffness.The parameters of the fiber/soil interface obtained from the proposed model can serve as input parameters for discrete framework of fiber-reinforced soil that requires independent evaluation of soil and fiber/soil interface.

关 键 词：纤维加筋土 相互作用 界面抗剪强度 渐进性破坏 拉拔 

分 类 号：TU43[建筑科学—岩土工程]