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.
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 problemsComplete homework problems to tackle issues that present themselves in the fieldStudy design procedures for each technique to simplify field implementationBrush 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.
In this research, we investigate complex infiltration processes in commonly existing sloping and/or layered soils by developing a series of physically-based models. This dissertation consists of four ...topically related but scientifically independent parts. First, a Green-Ampt type model for sloping layered soils (GASLS) is developed to represent the effects of layered soil formation and slope effect on infiltration using a hydraulic conductivity factor c and a slope factor. Guidelines to estimate the factor c are established and the effects of the slope are discussed. Second, a new analytical infiltration model is proposed to determine water flow dynamics around layer interfaces during infiltration process in layered soils, including the unsaturated flow in the coarse soils underlying fine soils and the water backfill effect. The easily determined dynamic steady state effective water content profiles are used to predict the saturation state of all layers. Results demonstrate that the arrangement of contrasting soil layers significantly affects infiltration process. Third, an infiltration model based on the traveling characteristics of wetting front (TCWF model) is presented to simulate infiltration process on any slope angle, including the evolution of wetting front. The TCWF model accurately predicts the infiltration process by solving an ordinary differential equation, which avoids numerically solving the highly non-linear Richards equation and reveals two traveling characteristics of wetting front. Fourth, an infiltration and runoff model is developed for surface crust soils under unsteady rainfall events. The model extends the flux-concentration relation and adopts time compression concept with consideration of the unsaturated flow in subsoil layer. The model predicts well actual runoff comparing to measured data from field experiments.
This book presents the latest thinking and techniques in the assessment of natural and man-made slopes, and the factors that cause them to survive or crumble. Using clear, concise language and ...practical examples, the book explains the practical aspects of geotechnical engineering as applied to slopes and embankments. The new Second Edition includes a thorough discussion on the use of analysis software, providing the background to understand what the software is doing, along with several methods of manual analysis that allow readers to verify software results. The book also includes a new case study about Hurricane Katrina failures at 17th Street and London Avenue Canal, plus additional case studies that frame the principles and techniques described. Slope stability is a critical element of geotechnical engineering, involved in virtually every civil engineering project, especially highway development.
The characterization of silty soils is usually designated by the percentage of silt
contained within the soil matrix, along with the soil’s void ratio, which is used to
describe the soil’s current ...state. The use of these parameters to assess a soil’s strength
and undrained behavior is limited when finer material is contained within the soil.
Therefore, additional parameters must be considered in order to correctly assess the
strength and liquefaction potential of silty soils. These additional parameters include the
skeleton void ratio, equivalent void ratio and granulometric factors. The current research
investigates the influence of granulometric parameters, specifically the Median Grain
Size Ratio (D50/d50), denoted as μDR (or MDR within graphs and charts), on the strength
and liquefaction potential of loose silty sands. A series of undrained monotonic triaxial
compression tests (σ3’= 69, 83, and 103 kPa) are performed on reconstituted soil samples,
using three different base sand samples and a constant silt material. As a result, three distinct median grain size ratios (μDR = 4.2, 6.75, and 9) were tested with fines content
ranging from 0-30% for each μDR. The undrained shear strength at all confining pressures
tends to increase with in μDR; beyond 10% fines content there was no noticeable influence
of μDR. At any μDR the excess PWP is higher than that of clean sand, when fines content is
larger than 5% fines content. The slope of the instability line and phase transformation
line are directly affected by the μDR and fines content, with an increase in the instability
line and decrease in the phase transformation line with a growing μDR. The results
indicate loose granular fills can be designed to be stronger and more resilient under
extreme conditions by careful choice of materials in which the μDR>6.75 and the fines
content does not exceed 10%.
Includes bibliography.
Thesis (M.S.)--Florida Atlantic University, 2016.
FAU Electronic Theses and Dissertations Collection
Road construction is mostly passed through mountainous regions or hilly terrains in Turkey like in all world. In hence, roadway construction and widening are being constructed through blasting and ...excavation, leading to rock slope instabilities and failures then poses threats to life and property. The reasons for failure sometime after construction are likely due to the deterioration of rock masses in cut slopes. However, slope instability and failures mainly occur due to adverse slope geomorphological complexities, joint discontinuities, weathering, man-made activities, unloading; and several induced factors such as seasonal heavy rainfall events, snow coverage, etc. The objectives of this paper are therefore to identify the most significant parameters influencing the behavior of cut slope rock masses with employing SMR,and to perform a preliminary slope instability assessment along roadway D340- 41.42, southwest of Turkey, where slopes located in a region of Taurus’s rugged terrains with known complex geometry, then propose a suitable control measures to mitigate potential failures of rock slope stability. In this study, 19 rock cuts are selected based on the observed failure mechanisms, slope geometry and materials. A systematic site investigation incorporating relevant engineering geological and geotechnical parameters were carried out in detail. Based on slope instability observations and SMR results rating, concluded that these slopes were widely controlled by discontinuities (structurally controlled failures). As well, SMR classification scheme was successfully used for failure classification in Taurus’s terrains. Finally, slope flattening with various angles method, wire mesh, toe support by detached rock blocks and drainage ditches re-design are proposed as a remedial measurement to protect road slope stability from failure.
This book describes and evaluates 30 projects from across the United States where bio-stabilization was used to address a detrimental naturally occurring process or byproduct of the built ...environment. Each project is illustrated with distinctive photographs.
The most common types of blasting damage are caused by ground vibration. The sudden acceleration of the rock by the detonation energy acting on the drill-hole generates an intense stress wave of both ...transverse and longitudinal wave motions in the surrounding rock. Key issues associated with the process of excavation and tunnelling include blast and, to a lesser extent, other construction vibration affecting the integrity of surface structures and slopes stability. The stability of slopes subject to ground vibration, which is induced by rock blasting, may be assessed by different approaches. In this paper, pseudo-static and dynamic analysis approaches are discussed. In both approaches, analysis of the dynamics response of slopes to the bedrock vibration in association with the calculation of the allowable vibration limits (ie. critical peak particle velocity (PPV)) and charge weight per delay is presented. A worked example is given to illustrate the use of the method. The allowable charge weights per delay for rock blasting that may impact on the stability of slopes can be estimated using simple approaches, either the pseudo-static or dynamic analysis. Both approaches can give a controllable safety limits for the works. Thus, the blasting works can be carried out safely with no damage or excessive ground movements to the slopes and other sensitive receivers if the allowable PPV and charge weights are followed, and the specifi ed monitoring works are carried out.
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