NEESR-CR: Earthquake Performance of Full-Scale Reinforced Soil Walls

该奖项是NSF 09-524项目招标“小乔治·e·布朗地震工程模拟（NEES）研究网络（NEESR）”竞赛的结果，包括加州大学圣地亚哥分校和新墨西哥理工大学（子奖项）。该项目将利用加州大学圣地亚哥分校的NEES设备站点。土挡结构的动力响应和性能传统上是通过测试小型物理模型来测量的，这已经产生了有价值的信息，但对于现场结构来说，这是一种妥协。为了更好地了解土挡土墙的抗震性能，需要进行全面的试验。该项目的目标是对使用现实材料和方法建造的全尺寸（10米）加筋土挡土墙的地震性能进行独特的实验研究。考虑到这些墙将比以往任何研究都要高几倍，因此提出的工作的重点将是墙高对土体加固整体系统响应和动力分布的影响。其他重点领域将是墙后的动土压力，动力荷载对土与加固单元之间荷载传递机制的影响，以及动力荷载后墙的永久变形。拟议的测试将使用NEES@ UCSD大型高性能室外振动台（LHPOST）进行。将在LHPOST上测试一个或多个全尺寸（10米）挡土墙。这些墙将使用实际的土壤类型、压实方法、加固和饰面元素来建造。为了进行这些全尺寸试验，将设计和建造一个独特的大型土壤约束箱。箱体尺寸为6米× 12米× 10米，高度接近平面应变试验条件。箱体的后边界条件可采取刚性后边界、吸能后边界和独特的应力控制/自由位移后边界三种构型。除了挡土墙外，土约束箱还将有许多其他的未来应用，包括土堤、未加固和加固的土坡、垃圾填埋场覆盖系统和桥台。本项目的理论价值有可能改变地震工程实践中加筋土挡土墙的设计方式。从这次试验中吸取的经验教训有望导致更合理的抗震设计程序，从而有望减少我们国家和全球民用基础设施的这一重要组成部分的地震风险。预计，该土约束箱一旦建成，将对岩土地震工程研究和专业团体产生广泛而广泛的影响。在加州大学圣地亚哥分校，该设施将为研究生研究人员、本科生研究助理和注册加州大学圣地亚哥分校课程的学生带来令人兴奋的教育体验，并提供令人兴奋的拓展机会，向更大的南加州地区展示当前先进的工程研究。该项目的数据将存档，并通过NEES数据储存库向公众提供。该奖项是国家减少地震灾害计划（NEHRP）的一部分。

This award is an outcome of the NSF 09-524 program solicitation "George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)" competition and includes the University of California-San Diego and New Mexico Tech (subaward). This project will utilize the NEES equipment site at the University of California-San Diego. The dynamic response and performance of earth retaining structures has traditionally been measured by testing small physical models, which have yielded valuable information but represent a compromise with respect to field structures. What is needed for a better understanding of the earthquake performance of soil retaining walls is full-scale testing. The objective of the project is to perform a unique experimental investigation of the earthquake performance of full-scale (10 m) reinforced soil retaining walls constructed using realistic materials and methods. Considering that these walls will be several times taller than for any previous research, a key focus of the proposed work will be the influence of wall height on overall system response and distribution of dynamic forces in soil reinforcement. Other focus areas will be dynamic earth pressure on the back of the wall, effects of dynamic loading on load transfer mechanisms between soil and reinforcing elements, and permanent wall deformations after dynamic loading.The proposed tests will be conducted using the NEES@ UCSD large high performance outdoor shake table (LHPOST). One or more full-scale (10 m) retaining walls will be tested on the LHPOST. These walls will be constructed using realistic soil types, compaction methods, reinforcement, and facing elements. In order to conduct these full-scale tests, a unique large soil confinement box will be designed and constructed. The box will measure 6 m × 12 m × 10 m high and will closely approximate plane-strain test conditions. The rear boundary condition for the box can take three configurations: rigid back boundary, energy absorbing back boundary and a unique stress-controlled/free-displacement back boundary. In addition to retaining walls, the soil confinement box will have many additional future applications including soil levees, unreinforced and reinforced soil slopes, landfill cover systems, and bridge abutments.The intellectual merit of this project has the potential to transform the way in which reinforced soil retaining walls are designed in earthquake engineering practice. Lessons learned from this testing are expected to lead to more rational seismic design procedures, which in turn are expected to reduce the seismic risk for this important component of our national and global civil infrastructure.It is expected that, once constructed, the proposed soil confinement box will provide extensive broader impacts to the geotechnical earthquake engineering research and professional communities. At UCSD, this facility will lead to exciting educational experiences for graduate student researchers, undergraduate student research assistants, and students enrolled in UCSD courses, and provide for exciting outreach opportunities to showcase current advanced engineering research to the greater Southern California area. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).