Daniel Ruffing

Daniel Ruffing
Geo-Solutions, Inc. · www.geo-solutions.com

BSc, MSc Civil and Environmental Engineering

About

58
Publications
27,549
Reads
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254
Citations
Introduction
Mr. Ruffing serves as a Vice President for Geo-Solutions, Inc. (GSI) working out of New Kensington, PA. In addition to occasionally managing projects, Dan is responsible for facilitating the quality control, marketing, business development, and estimating functions at GSI for projects including slurry walls, soil mixing, jet grouting, and other specialty geotechnical contracting techniques. His experience is based in field experience, project management, and administrative management at GSI.
Additional affiliations
January 2019 - present
Geo-Solutions, Inc.
Position
  • Vice President
January 2016 - December 2018
Geo-Solutions, Inc.
Position
  • Manager
December 2011 - December 2015
Geo-Solutions, Inc.
Position
  • Project Manager
Education
May 2008 - August 2009
Bucknell University
Field of study
  • Civil and Environmental Engineering
September 2004 - May 2008
Bucknell University
Field of study
  • Civil and Environmental Engineering

Publications

Publications (58)
Preprint
Full-text available
Field sampling and laboratory testing for quality control are critical in soil mixing and slurry trenching applications. In order for a sampling and testing program to be effective, it must be completed in such a way that it provides an accurate representation of the installed product. There are many standards for sampling and testing geo-structura...
Preprint
Full-text available
Since the early 80's, US practitioners have increasingly used a one-step slurry trenching process wherein the excavation slurry hardens in place to form the final backfill, termed a self-hardening slurry (SHS) trench. In some cases, this technique offers technical advantages over other cutoff wall techniques, even other slurry trenching methods, fo...
Chapter
Full-text available
A fracture grouting program with a suspension grout would seem reasonable based on the given information. Grouts with ingredients such as cement and bentonite are suspension grouts, whereas grouts with ingredients such as silicates are solution grouts. Microfine cement has obvious advantages for grouting in that the small particle size allows for u...
Chapter
Full-text available
Mechanical stabilization of soil to improve its properties and performance typically involves adding plastic or metal materials to the soil. Mechanical reinforcement adds tensile strength to soils. The inclusion of these materials allows the engineer to meet client needs faster and more cost-effectively. Geosynthetic reinforcement costs are a small...
Book
Full-text available
Ground improvement has been one of the most dynamic and rapidly evolving areas of geotechnical engineering and construction over the past 40 years. The need to develop sites with marginal soils has made ground improvement an increasingly important core component of geotechnical engineering curricula. Fundamentals of Ground Improvement Engineering a...
Chapter
Full-text available
This chapter presents the underlying soil mechanics for soil improvement by compaction and presents the means and methods by which compaction is achieved in the field. Shallow compaction is that which occurs beneath a surface-operated compactor such as a roller or plate compactor. Impact compaction is not generally used for shallow compaction but i...
Chapter
Full-text available
The fundamentals of soil behavior presented in this chapter are those most relevant and necessary to the understanding of ground improvement engineering. Water content, dry density, dry unit weight, specific gravity, total density, total unit weight, saturation, void ratio, and porosity are all defined ratios, the equations for which cannot be deri...
Chapter
Full-text available
Ground modification in the constructed environment is a new idea. For instance, the method of wattle and daub has been used for thousands of years to provide tensile reinforcement to clayey materials in buildings. The Roman road, Via Appia, now in modern-day Italy, is the earliest known example of the use of lime in ground improvement engineering....
Chapter
Full-text available
The ground improvement needed for excavation of deep shafts is ideally suited for ground freezing. Ground freezing has a niche particularly in deep tunneling work because a frozen shaft can be confirmed to be adequately formed prior to excavation, whereas other ground improvement techniques cannot provide such an assurance. The design of ground imp...
Chapter
Full-text available
The slurry, an engineered fluid, is usually comprised of bentonite and water and serves to support the sidewalls of the trench, i.e. maintain trench stability. When mixed with water at a ratio of approximately 5% bentonite and 95% water by mass, the resulting liquid demonstrates viscosity, density, and filtrate loss properties desirable for stable...
Chapter
Full-text available
The American Society of Testing and Materials and the International Organization for Standardization are two major standards bodies that publish test procedures to determine the engineering properties of geosynthetics. The relevant standards for applications in this text are: All polymeric geosynthetics break down in ultraviolet light, present in s...
Chapter
Full-text available
This chapter focuses on the future methods in ground improvement is organized in a principled way to include developments in biogeotechnical methods, in materials, and in construction monitoring. While ground improvement engineering is a relatively new field within geotechnical engineering, many ground improvement technologies have matured and, at...
Chapter
Full-text available
This chapter discusses the areas of earth reinforcement are examined, including: Mechanically stabilized earth walls and embankments over stiff ground often involve the use of geosynthetics although metal reinforcement is also used. MSE walls are quick to construct, use a wider variety of backfill soils, are inexpensive, and can be easily formed in...
Chapter
Full-text available
The ground can be improved with soil mixing by introducing additives into the subsurface while mixing the additives with the in situ soil to create a mixture that has improved physical properties, engineering properties, and/or chemical characteristics. Excavator bucket mixing is commonly used for shallow environmental soil mixing applications due...
Chapter
Full-text available
Vacuum consolidation also applies a load on the ground surface, increasing the effective stress. While vacuum consolidation has wide application over a variety of soft and compressible fine-grained soils, it is particularly advantageous for the consolidation of clay slurries that are too soft/weak for a surcharge. The nature of the subsurface may l...
Conference Paper
Full-text available
Soil bentonite (SB) slurry trench cutoff walls have been widely used for over 40 years to control groundwater flow, seepage through dams and levees, and contaminant transport. The hydraulic conductivity of SB backfill is stress dependent, and the concept that the state-of-stress in SB slurry trench cutoff walls is less than geostatic was first publ...
Preprint
Full-text available
Soil bentonite (SB) slurry trench cutoff walls have been widely used for over 40 years to control ground water flow, seepage through dams and levees, and contaminant transport. The hydraulic conductivity of SB backfill is stress dependent and the concept that the state-of-stress in SB slurry trench cutoff walls is less than geostatic was first publ...
Conference Paper
Full-text available
Defects in soil-bentonite (SB) slurry trench cutoff walls may reduce the effectiveness of the engineered structure to minimize groundwater flow and contain pollutants. One potential construction defect identified for SB cutoff walls is the presence of granular material in the wall due to sidewall collapse or sedimentation on the backfill slope and/...
Chapter
Full-text available
Vertical barriers have long been used to control groundwater flow and subsurface contaminant migration from contaminated land sites. Commonly employed vertical barrier types available to owners and designers include those constructed using slurry trenching techniques such as soil-bentonite (SB), and cement-bentonite with slag (slag-CB), in situ soi...
Preprint
Full-text available
In recent years, the chain-style trencher has been proven a valuable tool for installing vertical walls on challenging sites where conventional methods may be less desirable. Like many tools, trenchers are most effective when used with the right application. Trenchers are commonly used for applications that could also be completed with conventional...
Conference Paper
Full-text available
Soil mixing has been used around the world for geotechnical construction for nearly 50 years. After its introduction into the United States market in the late 1980s, soil mixing was gradually adopted for environmental remediation driven by increasing environmental regulations and clean-up needs. Since these early applications, soil mixing has grown...
Conference Paper
Full-text available
Vertical cutoff, or barrier, walls are an integral part of environmental site remediation efforts. Vertical barriers are commonly deployed to limit the influx of clean ground water and/or to control the off-site migration of contaminated groundwater. The level of detailed design consideration devoted to the vertical cutoff wall component varies wid...
Conference Paper
Full-text available
In 2014, Canada Geo-Solutions Inc. (CGSI) completed a deep groundwater cutoff wall on the Avalon Peninsula of Newfoundland & Labrador using the slurry trenching installation method with a soil-cement-bentonite backfill. The objective of the project was to cutoff groundwater flow from the adjacent bay so that a deep, large excavation, approximately...
Conference Paper
Full-text available
Soil bentonite (SB) slurry trench cutoff walls have been widely used for over 40 years to control ground water flow through and beneath dams and levees and to control subsurface contaminant transport at contaminated sites. The idea that the state-of-stress in SB slurry trench cutoff walls is less than geostatic was first published over 30 years ago...
Conference Paper
Full-text available
Vertical barriers have long been used to control groundwater flow and subsurface contaminant migration from contaminated land sites. Commonly employed vertical barrier types available to owners and designers including those constructed using slurry trenching techniques such as soil-bentonite (SB), and cement-bentonite with slag (slag-CB), in situ s...
Conference Paper
Full-text available
The closure of coal combustion residual (CCR) sites is occurring at an ever-increasing pace. Some of these sites may require ground water corrective action while other sites may require improvement of the stability of storage dikes, dams or embankments. For these situations, the well-established ground improvement technologies of in situ soil mixin...
Conference Paper
Full-text available
Soil bentonite (SB) slurry trench cutoff walls have been widely used for over 40 years to control ground water flow through and beneath dams and levees and to control subsurface contaminant transport at contaminated sites. The idea that the state-of-stress in SB slurry trench cutoff walls is less than geostatic was first published over 30 years ago...
Chapter
Full-text available
Soil-bentonite slurry trench cutoff walls have been employed widely in the US as engineered barriers to control groundwater flow and contaminant migration in the subsurface. The hydraulic conductivity of the soil-bentonite backfill is stress dependent and to better understand the in-situ stress state of soil-bentonite slurry trench walls, a wall wi...
Conference Paper
Full-text available
In 2017, In Situ Soil Mixing (ISSM) with cement was used to increase the shear strength of soft soils, including an organic peat layer, at the toe of an existing tailings dam. The ISSM soil-cement shear key elements were installed at the subject site using a track-mounted large-diameter single-auger soil mix drill rig fed with a simple grout consis...
Preprint
Full-text available
Soil-bentonite slurry trench cutoff walls have been employed widely in the US as engineered barriers to control groundwater flow and contaminant migration in the subsurface. The hydraulic conductivity of the soil-bentonite backfill is stress dependent and to better understand the in-situ stress state of soil-bentonite slurry trench walls, a wall wi...
Preprint
Full-text available
Abstract: Vertical barriers constructed using self-hardening slurries such as cement-bentonite were in use by the early 1970's and slag-cement-bentonite (slag-CB) slurries were first used in the UK in 1975 (Jefferis, 1997). Since then, a number of studies have been conducted to assess the properties of slag-CB, although the vast majority are labora...
Conference Paper
Full-text available
Soil-bentonite (SB) slurry trench cutoff walls are widely used for subsurface containment of contaminants and groundwater control. In many cases, particularly for environmental containment applications, the walls are intended to serve as a permanent barrier with a life expectancy measured in decades. The compatibility of these barriers with the env...
Research
Full-text available
Much of the information presented in this article should be considered common knowledge by those who are regularly engaged in geotechnical design or construction. This article was developed to provide the reader an overview of the author's thoughts and opinions about this important topic. The target audience is engineers or owners that are not comm...
Conference Paper
Full-text available
The adoption of the United States Environmental Protection Agency’s coal combustion residuals (CCR) regulations has stirred renewed interest in the stabilization/solidification (S/S) of fly ash residuals stored in landfills and surface impoundments. Soil mixing methods can be used to S/S a variety of materials to improve static slope stability, res...
Conference Paper
Full-text available
Geotechnical engineers understand there is uncertainty and risk in the input parameters for slope stability analyses and within the analysis methodologies themselves. Decades of research and inverse analyses of slope failures have resulted in widespread acceptance of certain factors of safety (FS) in typical situations, e.g., a static two-dimension...
Conference Paper
Full-text available
Soil-bentonite slurry trench cutoff walls are widely used for seepage control, levee repair, and pollutant containment. Their widespread use in these critical applications requires a better understanding of their as-built condition and long-term behavior. The in situ hydraulic conductivity of soil-bentonite cutoff walls is stress dependent. Changes...
Conference Paper
Full-text available
Soil-bentonite (SB) cutoff walls are commonly employed in the US to control groundwater flow and subsurface contaminant migration. In these applications, both the short-term (as built) integrity of the barrier and the potential for degradation in the integrity of the barrier over time are of critical importance. Although many laboratory studies hav...
Conference Paper
Full-text available
Soil mixing with pozzolanic binders is widely used for the stabilization and solidification of a variety of wastes in environmental applications as well as for bearing capacity improvement, earth retaining structures, and slope stabilization in geotechnical applications. This paper summarizes a series of recent projects at the Seneca Meadows Landfi...
Conference Paper
Full-text available
Soil-bentonite slurry trench cutoff walls have long been used to control ground water flow and contaminant transport. Previous studies have shown that hydraulic conductivity of the soil-bentonite backfill can be highly stress dependent. Furthermore, the stresses are dependent upon the load transfer generated by the formation sidewalls and the backf...
Conference Paper
Full-text available
Soil-bentonite slurry trench cutoff walls are the most common type of vertical cutoff wall used in the US for seepage control and for passive control of contaminant migration at environmental sites. Design considerations are often limited to constructability considerations and a target hydraulic conductivity. With design-build contracts common, the...
Conference Paper
Full-text available
Filter press tests are widely used for field quality control of bentonite slurry in slurry trench excavations and often are incorporated in technical specifications for assessing filtrate properties of initial (freshly mixed) slurry and occasionally for in-trench slurry. In some cases, the results of filter press tests conducted on in-trench slurry...
Research
Full-text available
Much of the information presented in this paper should be considered common knowledge by those who regularly encounter soil-cement mixtures. This paper was developed to provide the reader a comprehensive understanding of what soil-cement mixtures are and what physical properties to expect. The target audience is civil or geotechnical engineers t...
Chapter
Full-text available
5.1: Auger mixing is the most widely used technique of in-situ soil mixing and is especially useful for deeper applications, greater than 15 feet (4.6 m). Auger mixing is suitable for a wide range of soil types to depths in excess of 100 ft (30.8 m), although specialised methods are necessary for depths beyond 60 ft (18.5 m) below ground surface (...
Article
Full-text available
The Cone Penetration Test (CPT) is widely used for classifying soils and assigning soil properties to the subsurface because it is robust and can be used to quickly collect continuous data with depth. During and subsequent to the construction of a very deep soil-bentonite (SB) slurry trench cut-off wall in Mayfield NSW, Australia, the CPT was used...
Article
Full-text available
In practice, the term soil mixing commonly refers to any process by which reagents (wet or dry) are added to and mixed with unsuitable or contaminated soils. Other terms such as deep mixing method (DMM), shallow soil mixing (SSM), deep soil mixing (DSM), cutter soil mixing (CSM), and trench cutting remixing deep wall (TRD), are commonly used by Eng...
Conference Paper
Full-text available
This paper presents a case study of a deep soil-cement-bentonite (SCB) slurry trench cutoff wall constructed outside of Smithland, KY, in 2010. Installed to a maximum depth of 56 m, this cutoff wall is the deepest known seepage barrier installed using continuous trenching. The wall was installed around the perimeter of a deep excavation to reduce l...
Article
Full-text available
In situ solidification/stabilization (ISS) projects require a significant amount of characterization, sampling, and bench-scale testing in the design or feasibility phase to ensure a successful project. During this phase the proposed construction methods need to be considered, taking into account such things as slurry proportions, untreated soil ty...
Article
Full-text available
Soil mixing, originally developed as a means for structural soil improvement, has evolved into a system for effectively treating soil in situ to meet environmental remediation cleanup objectives. Using soil mixing in remedial efforts has significant advantages over alternative methods, specifically in terms of assuring consistent, measureable deliv...
Conference Paper
Full-text available
Soil mixing is widely used for environmental site remediation and ground improvement. The main objectives of soil mixing are to increase the strength and decrease the permeability of the soils. Conventionally, unreinforced soil mixing is an uncommon choice for an excavation support system, but a recent case study highlights the potential advantages...
Conference Paper
Full-text available
In situ soil mixing, in various forms, has been utilized in the geotechnical field for over 40 years. Originally, the primary applications of soil mixing were for the construction of foundation support elements and earth retention structures. Soil mixing techniques were first applied to environmental applications in the late 1980's and early 1990's...
Conference Paper
Full-text available
This paper presents the results of a field study to assess post-construction changes in the volumetric water content (θ) of a soil-bentonite (SB) slurry trench cutoff wall. Time domain reflectometry (TDR) sensors were installed in a newly-constructed SB cutoff wall in the summer of 2008 and were used to monitor θ as a function of depth within the S...
Data
Full-text available
Research has shown that cementitious additives used with or in place of Portland cement can drastically reduce the hydraulic conductivity and increase the strength of self-hardening cement-bentonite mixtures. The most common additive is blast furnace slag (aka slag or ground slag). Grade 120 provides the best property improvement, but Grade 100 and...
Data
Full-text available
Research has shown that cementitious additives used with or in place of Portland cement can drastically reduce the hydraulic conductivity and increase the strength of self-hardening cement-bentonite mixtures. The most common additive is blast furnace slag (aka slag or ground slag). Grade 120 provides the best property improvement, but Grade 100 and...
Article
Full-text available
Soil bentonite (SB) slurry trench cutoff walls are widely used to control the movement of ground water and subsurface contaminants. This paper presents findings from in situ tests conducted on an SB wall using the Marchetti Dilatometer Test (DMT). This paper also describes a modified lateral squeezing model that accounts for loading associated with...
Conference Paper
Full-text available
This paper presents a review of two models (i.e., arching and lateral squeezing) developed for predicting earth pressures in soil-bentonite (SB) cutoff walls. The assumptions of these existing models are discussed, a modified lateral squeezing (MLS) model is presented, and all three models are compared based on predicted horizontal stresses for rep...
Conference Paper
Full-text available
Soil bentonite (SB) slurry trench cutoff walls have been widely used in the USA to control ground water flow and the migration of contaminants in the ground water. While substantial laboratory testing has been conducted, field studies are limited. Researchers at Bucknell University were afforded the opportunity to conduct a suite of in situ tests...

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