Download or read book Performance of Stone Columns in Cohesive Soil written by Mahmoud Adel Mahmoud Khalifa and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stone columns are widely used and generally considered to be one of the most cost-effective and environmental-friendly soil improvement technique for highways and embankments. They are also used as drainage to reduce the consolidation period, which accordingly increases the bearing capacity, reduces settlement, and reduces the liquefaction potential. Current design theories used to estimate the bearing capacity of a group of stone columns are based on the unit cell or homogenized material concepts, which neglect the effect of the column interactions and installation technique. This thesis therefore presents an experimental investigation, together with numerical modelling, to examine the performance of a single stone column and group of stone columns subjected to vertical loading. An analytical model is developed to capture the effect of an arrangement of stone columns and the mode of failure within a column and the surrounding soft clay material. A single stone column and a group of stone columns were investigated in a large-scale experimental set-up. The testing program was divided into four steps: (a) filling the testing tank with the clay, (b) installing the stone columns in the clay bed, (c) extracting samples of the reinforced soil (a block of stone columns surrounded by the soft clay loading), and (d) testing the samples in a triaxial apparatus. The results showed that the mode of failure of the reinforced soil depends on the column spacing and the strength of the column materials and the surrounding soil. Numerically, a 3-D finite element model was developed to examine the influence of the governing parameters on the bearing capacity of the group. The model was validated against experimental results from this study and results available in the literature. The numerical model was used to simulate the actual driving process during installation of the columns. The model was then used to predict the actual failure plane under a rigid footing reinforced by stone columns for a given geometry/soil condition. An analytical model was developed utilizing the actual failure plane deduced from the numerical model to develop a theory to predict the bearing capacity of the reinforced soil. The theory developed was validated against the results obtained from the numerical model and results reported in the literature.

Download or read book Specifications for Constructing and Load Testing Stone Columns in Clays written by TD. Stark and published by . This book was released on 1991 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this paper is to provide guidelines for writing a performance specification for the construction and load testing of stone columns in cohesive soils. Specifications from five different sources, three specialty contractors and two agencies, were studied to develop the guidelines described herein. The two primary components of a performance specification are the performance criteria for the stone column foundation and the load testing procedures used to verify that the desired ground improvement has been achieved.

Download or read book Influence of smear and compaction zones on the performance of stone columns in lacustrine clay written by Jean Nicolas François-Xavier Gautray and published by vdf Hochschulverlag AG. This book was released on 2019-02-20 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Construction on soft soils is always accompanied by the risk of significant, time-dependent settlement and bearing capacity failure. As technical knowledge has advanced, optimised ground improvement has offered significant economic advantages in reducing net settlement and resisting failure by installation of more flexible and cost-effective stone columns or sand compaction piles in the ground, rather than more rigid inclusions such as steel or concrete piles. The stiffness and strength of the subsoil around the columns is greater, and the consolidation time is reduced through shorter (radial) drainage paths.

Download or read book Ground Treatment by Deep Compaction written by and published by Institution of Civil Engineers. This book was released on 1976 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geotechnical Performance of Group of Stone Columns written by Mohammad Etezad-Borojerdi and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Construction of Stone Columns written by Richard D. Barksdale and published by . This book was released on 1983 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Stone columns have been used since the 1950's as a technique for improving both cohesive soils and silty sands. Potential applications include (1) stabilizing foundation soils to support embankments and approach fills, (2), supporting retaining structures (including Reinforced Earth), bridge bent and abutment structures on slightly marginal soft to stiff clays and loose silty sands, (3) landslide stabilization and (4) reducing liquefaction potential of clean sands. Also, stone columns under proper conditions can greatly decrease the time required for primary consolidation. The report describes construction, field inspection, and design aspects of stone columns. Also, several case histories are described. Bearing capacity, settlement and stability design examples are given in the appendixes contained in Volume II, (FHWA/RD-83/027) as follows: Appendix A - Selected Contacts for Stone Columns, Appendix B - Local Bearing Failure of an Isolated Stone Column, Appendix C - Example Bearing Capacity Problems, Appendix D - Example Settlement Problems, Appendix E - Example Stability Problem, Appendix F - Rammed Franki Stone and Sand Columns"--Technical report documentation page.

Download or read book Deep Foundation Improvements written by Melvin I. Esrig and published by ASTM International. This book was released on 1991 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty-two papers from a symposium (on title), held in Las Vegas, January 1990, focus on deep foundation improvements through the formation of composite ground, and those related to improvement through compaction and densification. Annotation copyright Book News, Inc. Portland, Or.

Download or read book The Performance of Vibro Stone Column Reinforced Foundations in Deep Soft Ground written by Danielle McKelvey and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geosynthetic Encased Columns for Soft Soil Improvement written by Márcio Almeida and published by CRC Press. This book was released on 2018-10-10 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The geosynthetic encased column (GEC) is a relatively recent method developed for soft soil improvement. The method was firstly introduced as a concept in the 1980s and first practical applications started in the 1990s. GECs have been widely used in some parts of the world for the last three decades. However, there is no book in the literature summarizing the knowledge accumulated during this period in relation to this soft ground improvement technique. The purpose of this book is to provide readers with the GEC fundamentals and practical applications. Chapter 1 presents the general principles of this ground improvement technique including the methods used for GEC installation and how the material properties may be selected. Chapter 2 presents the design methods, thus settlement calculations by means of analytical methods and stability calculations by limit equilibrium methods are explained in detail. Chapter 3 presents calculation examples illustrating the usual steps to be done for both service limit state and ultimate limit state designs. Then field performances exemplifying practical applications of the GEC technique are presented in Chapter 4 for some case histories. Following numerical analyses, often used in design to complement analytical methods, are presented in Chapter 5. Annexes I and II at the end contain the charts developed to perform settlement calculations. The book combines the experiences of four authors with different academic and industry backgrounds to describe GEC design and performance. It is aimed at civil engineers in general, particularly geotechnical engineers, either working in design or in practice, at graduate students, and at senior undergraduate students.

Download or read book Numerical Simulations of Spread Foundations Supported on Stone Columns Using the Discrete Element Method written by Anibal Enrique Santos Marin and published by . This book was released on 2020 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: The implementation of stone columns as a ground improvement technique has become more popular in geotechnical construction practice as a result of their ability to improve strength, stiffness and permeability characteristics of weak clayey soil deposits. There are several analytical and empirical approaches to estimate the bearing capacity of stone column foundation systems; however, there is notable variation in the performance of these existing methods when compared with full-scale experimental results. For very weak cohesive soils (i.e., undrained shear strength less than 15 kPa), the use of conventional stone columns becomes restricted because of the insufficient confinement that these types of soils can provide to the columns. Hence, the inclusion of cement-coated aggregate has been developed as an alternative method to improve the efficacy of stone columns in soft soils. Limited information is available regarding the global performance, load-transfer mechanism, and design of these types of cemented stone columns under various field conditions. Efforts to refine the accuracy of current design methods and reinforcement techniques for conventional stone columns naturally point to the need for improving the understanding of the fundamental load-transfer mechanisms of stone columns. Three-dimensional discrete element method (DEM) simulations of small- and full-scale footing loading tests were developed to investigate the effects of aggregate strength, pier length, aggregate Young's modulus, area replacement ratio, cement content, and undrained shear strength of the matrix soil on the bearing pressure-displacement responses of isolated foundations supported on stone columns. The elemental responses of the aggregate and plastic matrix soil were calibrated against laboratory and in-situ test data from a well-characterized site and compared against the results of small- and full-scale footing loading tests. The column aggregate material was represented by discrete-deformable tetrahedrons in conjunction with strain-softening and strain-hardening models in order to improve the simulation of the nonlinear response of the cemented aggregate. Joined deformable blocks were employed to represent the continuous mechanical behavior of the surrounding clayey soil. The numerical results are in excellent agreement with the experimental laboratory and field data and provide improved estimates of the bearing pressure-displacement curves of the column-foundation systems investigated in this study. The Young's modulus of the aggregate column and the area replacement ratio were found to have the greatest influence on the bearing pressure-displacement response. The DEM results also improve the understanding of the effects of granular material-cementation on the performance of stone columns. At low cement contents the stone column exhibits a type of bulging failure mechanism similar to uncemented stone columns, but at higher cement contents (10 % in this study), bulging is not observed, and the behavior resembles more like that of a concrete pile. These types of behavioral differences also have different implications for single isolated stone columns and group column behavior.

Download or read book Applications of the State of the Art of Stone Columns liquefaction Local Bearing Failure and Example Calculations written by Richard D. Barksdale and published by . This book was released on 1987 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ground Improvement by Deep Vibratory Methods written by Klaus Kirsch and published by CRC Press. This book was released on 2016-08-05 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibro compaction and vibro stone columns are the two dynamic methods of soil improvement most commonly used worldwide. These methods have been developed over almost eighty years and are now of unrivalled importance as modern foundation measures. Vibro compaction works on granular soils by densification, and vibro stone columns are used to displace and reinforce fine-grained and cohesive soils by introducing inert material. This second edition includes also a chapter on vibro concrete columns constructed with almost identical depth vibrators. These small diameter concrete piles are increasingly used as ground improvement methods for moderately loaded large spread foundations, although the original soil characteristics are only marginally improved. This practical guide for professional geotechnical engineers and graduate students systematically covers the theoretical basis and design principles behind the methods, the equipment used during their execution, and state of the art procedures for quality assurance and data acquisition. All the chapters are updated in line with recent developments and improvements in the methods and equipment. Fresh case studies from around the world illustrate the wide range of possible applications. The book concludes with variations to methods, evaluates the economic and environmental benefits of the methods, and gives contractual guidance. The Open Access version of this book, available at http://www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license

Download or read book Principles and Practice of Ground Improvement written by Jie Han and published by John Wiley & Sons. This book was released on 2015-06-22 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gain a stronger foundation with optimal ground improvement Before you break ground on a new structure, you need to analyze the structure of the ground. Expert analysis and optimization of the geo-materials on your site can mean the difference between a lasting structure and a school in a sinkhole. Sometimes problematic geology is expected because of the location, but other times it's only unearthed once construction has begun. You need to be able to quickly adapt your project plan to include an improvement to unfavorable ground before the project can safely continue. Principles and Practice of Ground Improvement is the only comprehensive, up-to-date compendium of solutions to this critical aspect of civil engineering. Dr. Jie Han, registered Professional Engineer and preeminent voice in geotechnical engineering, is the ultimate guide to the methods and best practices of ground improvement. Han walks you through various ground improvement solutions and provides theoretical and practical advice for determining which technique fits each situation. Follow examples to find solutions to complex problems Complete homework problems to tackle issues that present themselves in the field Study design procedures for each technique to simplify field implementation Brush up on modern ground improvement technologies to keep abreast of all available options Principles and Practice of Ground Improvement can be used as a textbook, and includes Powerpoint slides for instructors. It's also a handy field reference for contractors and installers who actually implement plans. There are many ground improvement solutions out there, but there is no single right answer to every situation. Principles and Practice of Ground Improvement will give you the information you need to analyze the problem, then design and implement the best possible solution.

Download or read book Ground Improvement Third Edition written by Klaus Kirsch and published by CRC Press. This book was released on 2012-11-26 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: When finding another location, redesigning a structure, or removing troublesome ground at a project site are not practical options, prevailing ground conditions must be addressed. Improving the ground—modifying its existing physical properties to enable effective, economic, and safe construction—to achieve appropriate engineering performance is an increasingly successful approach. This third edition of Ground Improvement provides a comprehensive overview of the major ground improvement techniques in use worldwide today. Written by recognized experts who bring a wealth of knowledge and experience to bear on their contributions, the chapters are fully updated with recent developments including advancements in equipment and methods since the last edition. The text provides an overview of the processes and the key geotechnical and design considerations as well as equipment needed for successful execution. The methods described are well illustrated with relevant case histories and include the following approaches: Densification using deep vibro techniques or dynamic compaction Consolidation employing deep fabricated drains and associated methods Injection techniques, such as permeation and jet grouting, soil fracture grouting, and compaction grouting New in-situ soil mixing processes, including trench-mixing TRD and panel-mixing CSM approaches The introductory chapter touches on the historical development, health and safety, greenhouse gas emissions, and two less common techniques: blasting and the only reversible process, ground freezing. This practical and established guide provides readers with a solid basis for understanding and further study of the most widely used processes for ground improvement. It is particularly relevant for civil and geotechnical engineers as well as contractors involved in piling and ground engineering of any kind. It would also be useful for advanced graduate and postgraduate civil engineering and geotechnical students.

Download or read book From Research to Practice in Rammed Aggregate Piers written by Hamed Niroumand and published by LAP Lambert Academic Publishing. This book was released on 2012-04 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stone columns have been used since the 1950's as a technique for soil improvement such as cohesive soils and silty cohesion less soils. Stone column s applications includes (1) stabilizing the foundation soils to support embankments, approach fills and reconstruction work on weak cohesive soils, (2) supporting retaining structures (including Reinforced Earth), bridge bent and abutment structures on slightly marginal soft to stiff clays and loose silty sands, (3) landslide stabilization and (4) reducing liquefaction potential of clean sands. Also, stone columns under proper conditions may be greatly decrease the time required for primary consolidation. The stone column technique of ground behavior has proven successful in (1) improving slope stability of both embankments and natural slopes, (2) increasing bearing capacity, (3) reducing total and differential settlements, (4) reducing the liquefaction potential of sands and (5) increasing the time rate of settlement. Stone column construction involves the partial replacement of unsuitable subsurface soils with a compacted vertical column of stone that usually completely penetrates the weak strata.

Download or read book Stone Columns and Reinforced Stone Columns As Soil Improvement Techniques written by Hamed Niroumand and published by . This book was released on 2013-07-31 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stone columns have been used since the 1950's as a technique for soil improvement such as cohesive soils and silty cohesion less soils. Stone column's applications includes (1) stabilizing the foundation soils to support embankments, approach fills and reconstruction work on weak cohesive soils, (2) supporting retaining structures (including Reinforced Earth), bridge bent and abutment structures on slightly marginal soft to stiff clays and loose silty sands, (3) landslide stabilization and (4) reducing liquefaction potential of clean sands. Also, stone columns under proper conditions may be greatly decrease the time required for primary consolidation. The stone column technique of ground behavior has proven successful in (1) improving slope stability of both embankments and natural slopes, (2) increasing bearing capacity, (3) reducing total and differential settlements, (4) reducing the liquefaction potential of sands and (5) increasing the time rate of settlement. Stone column construction involves the partial replacement of unsuitable subsurface soils with a compacted vertical column of stone that usually completely penetrates the weak strata.

Download or read book The Deep Mixing Method written by Masaki Kitazume and published by CRC Press. This book was released on 2013-02-21 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Deep Mixing Method (DMM), a deep in-situ soil stabilization technique using cement and/or lime as a stabilizing agent, was developed in Japan and in the Nordic countries independently in the 1970s. Numerous research efforts have been made in these areas investigating properties of treated soil, behavior of DMM improved ground under static and d