RUI: Pervious Concrete Piles: An Innovative Ground Improvement Alternative

RUI：透水混凝土桩：一种创新的地面改良替代方案

• 批准号: 0927743
• 负责人: Anne Raich
• 金额: $ 27.93万
• 依托单位: Lafayette College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0927743&HistoricalAwards=false
• 关键词: RUI; Pervious; Concrete; Piles; Innovative

This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5).Permeable granular piles (i.e., sand compaction piles, stone columns and rammed aggregate piers) are commonly used to support structures and highway facilities constructed on soft or loose soils subjected to static and seismic loading. Although the use of permeable granular piles increases the time rate of consolidation, reduces liquefaction potential, improves bearing capacity and stability, and reduces settlement of poor soils, these piles have a low stiffness and strength that depend on the properties of surrounding soil. Therefore, granular piles have limited use in very soft clays and silts, and in organic and peat soils. This research focuses on developing a new ground improvement alternative using pervious concrete piles to provide high permeability coupled with high stiffness and strength that are independent of surrounding soil properties.When compared to the properties of granular piles, pervious concrete materials provide comparable permeability, more than ten times the strength, and an increase of two orders of magnitude in modulus. The higher elastic modulus and strength of pervious concrete improves the load transfer and load-carrying capacity of the piles without compromising the benefits of high permeability. Using pervious concrete material will ultimately result in reducing the required area replacement ratio, which will significantly reduce construction time and cost. Pervious concrete piles, which have strength and stiffness properties that do not depend on confinement provided by surrounding soil, will provide an effective ground improvement method for very soft clays and silts, and in organic and peat soils. In addition, pervious concrete piles can be reinforced with longitudinal corrosion-resistant steel rebars to improve their ductility and performance when subjected to seismic loading.The research objectives focus on developing pervious concrete mixtures for ground improvement applications and on experimentally characterizing the effects of several construction procedures on soil and pile properties and on soil-pile interaction. Small-scale laboratory experiments using instrumentation and advanced sensors are designed to understand the effects of installation procedures on the behavior of single pervious concrete piles and groups of pervious concrete piles subjected to vertical, uplift, lateral,and embankment loading conditions. The analytical work focuses on developing computational models that accurately predict the behavior of pervious concrete pile systems through three stages: pile installation, consolidation, and in-service loading. The analytical models will be calibrated using the results of the laboratory material and pile load tests and both sophisticated analytical methodologies for use by researchers and simplified analytical tools recommended for practicing engineers will be developed. The Soil-Structure Interaction Facility at Lafayette College, which was recently funded by the National Science Foundation?s Major Research Instrumentation Program, will be used to conduct the experimental and analytical studies. The research will benefit significantly from the collaboration of the Geopier Foundation Company in the design and conduction of the experimental program. The research project team consists of faculty and students from Lafayette College, which is an undergraduate non-Ph.D. granting institution, and engineers from Geopier Foundation Company. Two undergraduate students will be funded by the project each year. Two additional students will be funded through Lafayette College?s EXCEL Scholars Program, which supports collaborative research between high-performing students and faculty. The research team will also collaborate with the Pennsylvania STEM Initiative and an enrichment/gifted support specialist and teacher from the Easton Area School District, PA, in several outreach programs. The partnerships formed through these activities support the Pennsylvania?s STEM Initiative to dramatically increasing the number of P-20 students (especially females, minorities and the underrepresented) in Science, Technology, Engineering and Mathematics careers. The project team, in collaboration with the Northeast Regional Network of PA STEM, will work with students and teachers in several area K-12 schools (total ~4000 students). Specifically, participating in yearly workshops and ?Project Lead the Way? that engage students in high school pre-engineering programs and the YWCA?s ?Tech Gyrl? program that empowers middle school girls by developing computing skills will expose students and their teachers to the challenges associated with designing structures supported on poor soils. Through professional committee work and service, conference presentations, journal papers, and participating in the CMMI annual meeting; the PIs and students will disseminate the data, methods, and tools produced by this research effort nationally and internationally.

该奖项根据 2009 年美国复苏和再投资法案（公共法 111-5）提供资金。透水颗粒桩（即压实砂桩、石柱和夯实骨料桩）通常用于支撑在软土地基上建造的结构和公路设施。或承受静态和地震荷载的松散土壤。 尽管使用透水颗粒桩可以提高固结时间，降低液化潜力，提高承载力和稳定性，并减少贫瘠土壤的沉降，但这些桩的刚度和强度较低，具体取决于周围土壤的特性。 因此，颗粒桩在非常软的粘土和淤泥以及有机土和泥炭土中的使用有限。 这项研究的重点是开发一种新的地面改良替代方案，使用透水混凝土桩来提供高渗透性以及独立于周围土壤特性的高刚度和强度。与颗粒桩的特性相比，透水混凝土材料提供了可比的渗透性，超过强度增加十倍，模量增加两个数量级。 透水混凝土较高的弹性模量和强度提高了桩的荷载传递和承载能力，同时又不影响高渗透性的优点。 使用透水混凝土材料最终将减少所需的面积替换率，从而显着减少施工时间和成本。 透水混凝土桩的强度和刚度特性不依赖于周围土壤的限制，将为非常软的粘土和淤泥以及有机土和泥炭土提供有效的地面改良方法。 此外，透水混凝土桩可以用纵向耐腐蚀钢筋加固，以提高其在承受地震荷载时的延展性和性能。研究目标集中于开发用于地面改良应用的透水混凝土混合物，并通过实验表征几种施工的效果土和桩特性以及土-桩相互作用的程序。 使用仪器和先进传感器进行的小规模实验室实验旨在了解安装程序对单根透水混凝土桩和透水混凝土桩群在垂直、隆起、横向和路堤荷载条件下的性能的影响。 分析工作的重点是开发计算模型，准确预测透水混凝土桩系统通过三个阶段的行为：桩安装、固结和使用中加载。 分析模型将使用实验室材料和桩荷载测试的结果进行校准，并且将开发供研究人员使用的复杂分析方法和推荐给实践工程师的简化分析工具。 拉斐特学院的土壤-结构相互作用设施最近由美国国家科学基金会的主要研究仪器计划资助，将用于进行实验和分析研究。 该研究将受益于 Geopier 基金会公司在实验项目设计和实施方面的合作。该研究项目团队由拉斐特学院的教职员工和学生组成，该学院是一所本科非博士学位的大学。资助机构和来自 Geopier 基金会公司的工程师。 该项目每年将资助两名本科生。另外两名学生将通过拉斐特学院的 EXCEL 学者计划获得资助，该计划支持表现优异的学生和教师之间的合作研究。研究团队还将与宾夕法尼亚州 STEM 计划以及宾夕法尼亚州伊斯顿地区学区的丰富/天才支持专家和教师合作，开展多个外展项目。通过这些活动形成的合作伙伴关系支持宾夕法尼亚州的 STEM 计划，以大幅增加从事科学、技术、工程和数学职业的 P-20 学生（特别是女性、少数族裔和代表性不足的学生）的数量。该项目团队将与 PA STEM 东北地区网络合作，与多个地区 K-12 学校（总计约 4000 名学生）的学生和教师合作。具体来说，参加年度研讨会和“项目引领之路”让学生参与高中工程预科课程和 YWCA 的“Tech Gyrl”。通过发展计算技能来增强中学生能力的计划将使学生及其教师面临与在贫瘠土壤上设计结构相关的挑战。通过专业委员会的工作和服务、会议演讲、期刊论文、参加CMMI年会； PI 和学生将在国内和国际上传播这项研究工作产生的数据、方法和工具。