Geotechnical Engineering Commons^™

Evaluation Of New Methods For Determining The Minimum And Maximum Index Densities Of Sand, Hossein Ganji

Geotechnical Engineering Masters Projects

This thesis presents the results of a laboratory testing program that evaluated the applicability of a new-established method for determining minimum and maximum dry density values by Norwegian Geotechnical Institute (NGI). Seven fine to medium grained cohesionless sand batches with different inclusion of fines content were selected for a series of testing programs in compliance with American Society for Testing and Materials (ASTM) and NGI recommendations. All three methods of ASTM D4254 – 16 and method 1B of ASTM D4253 – 16 were applied for minimum and maximum dry density determination, respectively. The results compared with the NGI minimum and …

Evaluation Of Helical Piles As Anchors For Floating Offshore Wind Turbine Foundation Systems, Martha Shannon Harris

Geotechnical Engineering Masters Projects

The development of floating offshore wind energy is essential for growth of the renewable energy industry, and to decrease the reliance on fossil fuels and emission of greenhouse gasses. Advances in ease of construction and installation of turbines can make the floating offshore wind industry more marketable and feasible on a large scale; this can in part be achieved by innovation in foundation anchoring systems.

This thesis presents an evaluation of helical pile foundations for offshore deep-water application as anchors for floating offshore wind systems with catenary mooring lines in clay and sandy soils. This research outlines the influence of …

Influence Of Reconsolidation Procedure On Small Strain Shear Modulus And Undrained Shear Behavior Of Silts Subjected To Tube Sampling Disturbance, Shreya Pandey

Geotechnical Engineering Masters Projects

This thesis presents results of a laboratory testing program that studied the effects of laboratory simulated tube sampling disturbance on the undrained shear strength behavior of reconstituted low plasticity silts at overconsolidation ratios of 1.0 and 3.6. The three test soils consisted of two different mixtures of kaolin clay and silica silt and a reconstituted natural Dedham silt. Triaxial tests with bender elements were conducted on the reconstituted samples using the Ideal Sampling Approach (ISA) followed by post-ISA reconsolidation and undrained shear. The specimens were subjected to ± 1% and ± 3% ISA axial strain cycles. Changes in shear wave …

Aging And Property Changes Of Clay Around Driven Piles, Hasian R. Zapata

Geotechnical Engineering Masters Projects

The purpose of this research was to determine how soil disturbance caused by the installation of piles (of differing types and geometries) in clay affect the short and long-term capacity of piles. Several types of piles were installed in lightly overconsolidated clay at three different test sites in Amherst, Massachusetts. Before and after pile installation, an in-situ testing program consisting of field vane shear tests was carried out around piles installed at one of the three testing sites. Undrained shear strength and water content profiles allowed for an approximate determination of changes in the behavior of the clay surrounding some …

Fracture Toughness Assessment Of Shales By Nanoindentation, Yunqui Liu

Geotechnical Engineering Masters Projects

Nanoindentation has been reported as an effective tool for realizing the strength and stiffness (modulus of elasticity) of different materials including thin film materials, cementitious composites and rock or clay mineral materials. However, to the best of the authors’ knowledge, nanoscale fracture of shale materials has rarely been examined. Fracture toughness property of shale has been typically studied by observing crack growth of notched macroscale specimens subjected to flexural or tension loads. This research discusses the possible characterization of fracture toughness of shale using contact mechanics at the nanoscale. The analysis method is based on two traditional fracture toughness measurement …

The Effect Of Immediate Saline Water Curing On The Strength, Composition, And Microstructure Of Geopolymer Cement, Lindsay Duran

Geotechnical Engineering Masters Projects

The low durability and low resistance of ordinary Portland cement led to an investigation into the viability of geopolymer cement as an alternative to well cement for soil improvement in saline environments and well cement in offshore drilling and carbon sequestration projects. This thesis presents the results of a laboratory investigation into the effect of immediate saline water curing on the strength, composition, and microstructure of geopolymer cement. The experimental program began with preliminary work in designing adequate geopolymer cement and developing a curing environment that simulates offshore or underground conditions and facilitates immediate curing of cement specimens. Pure geopolymer …

Investigation Of Installation Torque And Torque-To-Capacity Relationship Of Screw-Piles And Helical Anchors, Mark Ruberti

Geotechnical Engineering Masters Projects

Installation torque has been used in the design of helical anchors (Screw-Piles) since the late 1960s. KT factors released by the manufacturer relating ultimate capacity of Screw-Piles to installation torque allow engineers to calculate a design installation torque which is necessary to achieve the design capacity in the field. These KT factors have been based on shaft geometry alone (Hoyt and Clemence 1989). Recent full-scale uplift tests in both clay and sand have shown that the traditional methods of analysis for estimating uplift capacity based on microscale tests are not representative of macroscale behavior. A soil wedge does not fully …

Study Of Minimum Void Ratio For Soils With A Range Of Grain-Size Distributions, Zhenning Yang

Geotechnical Engineering Masters Projects

Minimum void ratio or maximum packing density is an important soil property in geotechnical engineering. It apply to volume change tendency control, fluid conductivity control and particles movement.

Previous researchers have attempted to predict maximum packing density by empirical/graphic method, rock correction method, alpha method. Based on the concepts of F. de Larrard in concrete mixture research, we have developed a mathematic model that can predict the minimum void ratio for soils with a wide range of particle size.

Probability density function-lognormal distribution was tested and used to provide a reasonable representation for soils with a range of grain-size distribution. …

Hydrogeologic Characterization Of A Till Mantled Leaky Fractured Bedrock Aquifer, William Lukas

Geotechnical Engineering Masters Projects

In glaciated areas till can serve as a leaky aquitard for fractured bedrock aquifers. The characterization of a leaky till mantled fractured bedrock aquifer is presented. Multiple high resolution data sets were collected in response to unprecedented changes in the hydraulic head at a research site in eastern Massachusetts. Local scale aquifer and aquitard hydraulic conductivity, transmissivity and storativity values are determined through the analysis of purge recovery tests using Ostendorf and DeGroot (2010) and Cooper et al (1967) theories. The local scale parameters are in turn used to determine large scale aquifer transmissivity and storativity through an analysis of …