Strain Distribution Within Geosynthetic Reinforced Soil Slopes

土工合成材料加筋是公路路堤和挡土墙工程的一种非常有吸引力的替代方案，因为它与传统的挡土结构相比具有很好的经济效益。加筋土坡的设计通常使用基于软件的技术(极限平衡)，这需要关于加筋单元内应变分布的重要假设。然而，到目前为止，假定的应变分布还没有根据监测结果得到充分验证。这项研究的总体目标是生成和集成(通过离心机建模、数字图像分析和有限元分析)数据，这些数据将为加筋土坡设计中采用的应变分布提供明确的答案。具体地说，这个项目将综合以下五个阶段的结果：(I)进行离心机模型调查，以产生关于土工合成加筋土坡在工作应力条件下的性能的实验数据；(Ii)进行数字图像处理和分析工作，以从机上拍摄的离心机模型的图像中收集和评估应变信息；(Iii)进行数值(有限元)研究，以编制加筋土坡行为的参数评估，在与前一个实验阶段收集的数据进行校准之后；(Iv)评估工作，将关于加筋土坡应变分布的结果纳入当前的加筋土指南；和(V)将离心机岩土模型的数字视频剪辑纳入多媒体演示的教育部分，用于本科生和研究生的岩土教学以及招收代表不足的少数族裔高中生参加工程课程。除了通过更好地了解应变分布模式来完善土工合成加筋土坡的设计准则这一具体目标外，拟议的研究还是国际土木工程学会正在积极发展的关于加筋土壤研究和国际土工学会岩土建模的更大的持续议程的基石。事实上，拟议的调查将启动实施科罗拉多大学岩土离心机测试中的数字图像分析的创新程序，将有助于正在进行的岩土系统物理和数值建模之间的交叉验证努力，并将促进将研究纳入工程教育。

Soil reinforcement using geosynthetics is a very attractive alternative for highway embankment and retaining wall projects because of the economic benefits it offers in relation to cenventional retaining structures. Desigh of reinforced soil slopes is typically performed using software-based techniques (limit equilibrium), which require significant assumptions regarding the distribution of strains within the reinforcement elements. However, to date, the assumed strain distributions have not been fully validated against monitored results. One consequence of this is a perceived overconservatism in design.The overall objective of this research initiative is to generate and integrate (via centrifuge modeling, digital image analysis, and finite element analysis) data that will provide a definite answer regarding the strain distribution to be adopted in reinforced soil slope design. Specificaly, this project will integrate results from the following five phases: (i) a centrifuge modeling investigation undertaken to generate experimental data on the performance fo geosynthetic reinforced soil slopes under working stress conditions; (ii) a digital image processing and analysis effort performed to collect and evaluate strain information from inflight-captured images of videotaped centrifuge models; (iii) a numerical (finite element) study performed to compile parametric evaluations of reinforced soil slope behavior, after having calibrated numerical procedures against data collected in the previous experimental phase; (iv) an evaluation effort to incorporate findings on reinforcement strain distribution into current reinforced soil guidelines; and (v) an educational component to integrate digital video clips of centrifuge geotechnical models into multimedia presentations to be used for undergraduate and graduate geotechnical instructions as well as for recruitment of underrepresented minority high school students into engineering programs.In addition to the specific goal of refining design guidelines for geosynthetic reinforced soil slopes by gaining better understanding of the pattern of strain distributions, the proposed research is the cornerstone of larger, ongoing agendas under active development on reinforced soil research by the PI and on geotechnical modeling at the PI's institution. In fact, the proposed investigation will initiate implementation of innovative procedures invilving digital image analysis in geotechnical centrifuge testing at the University of Colorado, will contribute to ongoing efforts of cross-validation between physical and numerical modeling of geotechnical systems, and will foster integration of research into engineering education.