Development of the Geoconstruction Information and Technology Selection Guidance System (2014)

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1C h a p t e r 1 This report describes the web-based information and guidance system developed as part of the second Strategic Highway Research Program Renewal Project R02 (SHRP 2 R02), Geo- technical Solutions for Soil Improvement, Rapid Embankment Construction, and Stabilization of the Pavement Working Plat- form. Project background, literature review, development, programming, and testing of the web-based information and guidance system are detailed in this report. Recommendations for future enhancements of this website are also presented. The web-based information and guidance system presented herein is intended to overcome many of the technical and non- technical obstacles encountered by engineers and other trans- portation personnel that prevent broader and effective use of geotechnical solutions on transportation infrastructure proj- ects. Geotechnical solutions are geoconstruction technologies or ground improvement systems that alter poor soil/ground conditions to meet project requirements. Project R02 includes both embankments and pavement foundations. The term geo- construction technologies describes all the technologies included in the R02 project. Even though many technologies included in the project are traditionally considered to be ground improve- ment technologies, some of these technologies are not typically grouped with ground improvement. Shrp 2 r02 project Background Although in existence for several decades, many geoconstruc- tion technologies face both technical and nontechnical obsta- cles preventing broader use in transportation infrastructure projects. The research team for SHRP 2 R02, Geotechnical Solutions for Soil Improvement, Rapid Embankment Con- struction, and Stabilization of the Pavement Working Plat- form, has investigated the state of practices of transportation project engineering, geotechnical engineering, and earthwork construction to identify and assess methods to advance the use of geoconstruction technologies. Such technologies are often underused in current practice, and they offer significant poten- tial to achieve one or more of the SHRP 2 Renewal objectives of rapid renewal of transportation facilities, minimal disrup- tion of traffic, and production of long-lived facilities. The R02 project encompasses a broad spectrum of materials, processes, and technologies within geotechnical engineering and geocon- struction that are applicable to one or more of the following three “elements” of construction (as defined in the R02 project scope): new embankment and roadway construction over unstable soils, roadway and embankment widening, and stabi- lization of pavement working platforms. The overall vision established for the project is “to make geo- technical solutions more accessible to public agencies in the United States for rapid renewal and improvement of the trans- portation infrastructure.” Phase 1 of the R02 project (completed in August 2008) consisted of six tasks focused on identifying those geotechnical materials, systems, and technologies that best achieve the SHRP 2 Renewal strategic objectives for the three elements. Explicit in the tasks was the identification and evaluation of technical issues; project development/delivery methods; performance criteria and quality control/quality assurance (QC/QA) procedures; and nontechnical issues that significantly constrain use of geotechnical materials, systems, and technologies. Through identification of obsta- cles, both technical and nontechnical, that constrain usage of geoconstruction methods, and mitigation strategies to over- come the obstacles, the research team developed an approach to identify existing and innovative technologies to enhance geotechnical solutions for transportation infrastructure. Phase 2 focused on 46 geotechnical materials, systems, and technologies (hereafter referred to as geoconstruction tech- nologies) that best achieve the SHRP 2 Renewal strategic objectives. These identified technologies are listed below: • Aggregate columns • Beneficial reuse of waste materials • Biotreatment for subgrade stabilization Introduction

2• Blasting densification • Bulk-infill grouting • Chemical grout injection systems • Chemical stabilization of subgrades and bases • Column-supported embankments • Combined soil stabilization with vertical columns • Compaction grouting • Continuous flight auger piles • Deep dynamic compaction • Deep mixing methods • Drill-and-grout and hollow bar soil nailing • Electroosmosis • Excavation and replacement • Fiber reinforcement in pavement systems • Geocell confinement in pavement systems • Geosynthetic-reinforced construction platforms • Geosynthetic-reinforced embankments • Geosynthetic reinforcement in pavement systems • Geosynthetic separation in pavement systems • Geosynthetics in pavement drainage • Geotextile encased columns • High-energy impact rollers • Hydraulic fill with geocomposite drains and vacuum consolidation • Injected lightweight foam fill • Intelligent compaction and roller integrated compaction monitoring • Jet grouting • Lightweight fill, EPS geofoam, low-density cementitious fill • Mechanical stabilization of subgrades and bases • Mechanically stabilized earth wall systems • Micropiles • Onsite use of recycled pavement materials • Partial encapsulation • Prefabricated vertical drains and fill preloading • Rapid impact compaction • Reinforced soil slopes • Sand compaction piles • Screw-in soil nailing • Shoot-in soil nailing • Shored mechanically stabilized earth wall system • Traditional compaction • Vacuum preloading with and without prefabricated verti- cal drains (PVDs) • Vibro compaction • Vibro concrete columns The selection of technologies to develop this list is primar- ily an outcome of the Phase 1 work of SHRP 2 R02. However, the list of technologies included in Phase 2 was slightly modi- fied as the result of extensive discussions between the research team and the advisory board and initial Phase 2 work. Forty technologies identified in the Phase 1 work were car- ried into the initial Phase 2 work. Two technologies, stone columns and rammed aggregate piers, were combined under the technology named aggregate columns. Biotreatment of subgrade stabilization was re-added (after Phase 1 deletion) to the list of technologies in Phase 2. Traditional compaction, a baseline technology that other technologies are compared to, was added in Phase 2. The geosynthetics in pavements technology from Phase 1 was subdivided into six separate technologies in the Phase 2 work. Shoot-in and screw-in soil nails were subdivided into two technologies in Phase 2. Fiber reinforcement of slopes was dropped in the Phase 2 work. Thus, a total of 46 technologies have been addressed in the Phase 2 work. Phase 2 included the development of a catalog of materials, processes, and systems for rapid renewal geoconstruction proj- ects; evaluation and listing of design guidance, QC/QA proce- dures, methods for estimating costs, and sample specifications; and development of an information and guidance system. A catalog was created to detail the requirements for guidance on design, QC/QA, costs, and specifications into an integrated catalog and an interactive selection assistance system. The catalog also contains information necessary for initial project applicability screening of each technology (i.e., depth limits, applicability to different soil types, acceptable groundwater conditions, applicability to different project types, ability to deal with project-specific constraints, and general advantages and disadvantages). The information and guidance system, the web-based system described in this report, provides immediate access to the information contained in the catalog. This web-based system is the umbrella project product; it contains all the primary products and tools developed by the R02 project team. project Statement Transportation engineers, geologists, planners, and officials lack a readily available means to access critical information for geoconstruction technologies and lack a tool to assist in deciding which technologies are potentially applicable to their project. The R02 products and tools are organized and pre- sented on a website in lieu of printed reports because of the advantages a web-based system provides to users. These advan- tages will significantly improve achievement of SHRP 2 Renewal objectives throughout the United States. Primary advantages of the web-based system are the following: • It is a living system—that is, updatable and expandable. • It is readily available. • It provides a forum for technology usage exchange between state transportation authorities.

3The goals of the web-based information and guidance system are: • Provide an information system that contains the technol- ogy catalog, selection system, and a glossary. • Provide a selection system as part of the information sys- tem to develop a short list of applicable technologies based on a few project and site characteristics. • Provide an interactive, fully functional, and populated pro- gram to house the information system and guide the user through the selection system. • Provide a glossary of the abbreviations and terms used throughout the information and selection system. report Organization Many details included in this report are specific to the devel- opment and testing of the web-based information system. Such details are typically omitted from software development reports. The intent of this report is to tell the story of the devel- opment of the web-based information and guidance system. A key attribute of a good process is one that can be “read, understood, questioned, communicated, modified, and most important, improved” (Rakitin, 1997). This report provides the information that will support future revisions of the web- based system (i.e., maintain it as a living system). In documenting the details of this development effort, over- lap between several sections of certain chapters and other sec- tions in other chapters could not be avoided. Cross-referencing is provided, as appropriate. anticipated Outcomes of project The primary value of the web-based information and guid- ance system is that it collects, synthesizes, integrates, and organizes a vast amount of critically important information about geotechnical solutions in a system that makes the infor- mation readily accessible to state transportation agency (STA) personnel who need it most. The web-based information and guidance system will be a valuable tool for engineers, planners, and transportation officials when evaluating poten- tial geoconstruction technologies. No system like this exists, either in hard form or through a programmed system. Providing critical path guidance for emerging technologies will decrease the time required for promising solutions to be used for infrastructure projects. Experienced engineers will benefit from the design, construction, and cost information provided in the catalog. Less-experienced engineers, planners, and others will benefit from the technology selection assistance portion of the system to assess the feasibility of technologies to address project requirements and constraints. STA managers and other personnel unfamiliar with geo construction tech- nologies can be directed to this site for introductory summary fact sheets and illustrative photographs. A significant benefit of the rule-based approach to the information and guidance system is the sharing of knowl- edge, especially when the knowledge is not the type of knowl- edge typically published in scholarly publications (Spring et al., 1991). The knowledge in the system addresses the prac- tical aspects of planning, design, construction, and cost, which benefits engineers and officials at all levels of experience. This knowledge is systematically and consistently addressed for each of the 46 technologies. Study Limitations Understanding the limitations of the information and guid- ance system are critical to proper implementation and use in practice. System limitations are detailed in detail in Chapter 6. Some of the limitations of the information and guidance sys- tem include the number of technologies considered in the system, the difficulty in measuring the results of the selection system against the opinion of an experienced geotechnical engineer, and the difficulty of anticipating possible project- specific scenarios. Although a large number of technologies are included, they were limited to fit the SHRP 2–defined scope of the R02 project. This information and guidance system provides tools for engineering of geotechnical solutions. It does not “engi- neer” solutions, because that must be performed on a project- specific basis.