Ultrasonic Pulse Velocity Tests on Compacted Soil

In This Paper, Results of a Series of Ultrasonic Pulse Velocity Tests on Compacted Soil Were Presented and Discussed. Ultrasonic Pulse Velocity Tests Provide Compression and Shear Wave Velocity Information that Can Be Used in Calculating Dynamic Elastic Moduli Such as Young\u27s Modulus and Shear Modulus. from the Test Results, Calculated Poisson\u27s Ratio Shows a Linear Relation with the Water Content in Compacted Soil, Which Leads to a Linear Trend in Both P and S Wave Velocity Against Water Content. Furthermore, Presenting Plots in Bulk Density Versus Wave Velocity Gives a Clearer Trend Than Dry Density Versus Wave Velocity. © 2009 ASCE

Modeling of minimum void ratio for sand–silt mixtures

Minimum void ratio or maximum packing density is an important soil property in geotechnical engineering. It correlates to the volume change tendency, the pore fluid conductivity, and the shear strength of the soil. In geotechnical engineering, it often requires to estimate the minimum void ratio for a sand–silt mixture with any amount of fines content, based only on few laboratory test results. The minimum void ratio for soil mixtures is usually estimated by methods based on, to some extent, an empirical approach, for example, the AASHTO coarse particle correction method. In this paper, based on a more fundamental approach using the concept of dominant particle network, we aim to develop a mathematical model that can predict the minimum void ratio for sand–silt mixtures with any amount of fines content. The developed model only requires two parameters for the prediction of minimum void ratios of soil mixtures with various fines contents. The developed model is evaluated by the experimental results on 33 types of soil mixtures available in the literature, including mixtures of sands (Ottawa sand, Nevada sand, Toyoura sand, Hokksund sand, etc), and silts (ATC silt, Nevada fines, crushed silica fines, grind Toyoura fines, etc). Comparisons of the results are discussed

Evaluation of Pre-Consolidation Stress Determination Methods

Pre-Consolidation Pressure Provides Valuable Information About Soil Behavior And, Specifically, Settlement under an Induced Load. Soil is Expected to Have Less Settlement Before its Pre-Consolidation Pressure and Much More Settlement after that Point. the Pre-Consolidation Pressure and the Compressibility of the Soil Can Be Determined from the Results of a One-Dimensional Consolidation Test. Different Methods Have Been Developed to Obtain the Accurate Pre-Consolidation Pressure from One Dimensional Consolidation Test Data. This Paper Presents and Discusses the Results of the One-Dimensional Consolidation Test Data from an Extensive Testing Program. the Test Specimens Used Were Obtained from Multiple Borehole Locations and Were Extracted using Shelby Tube Samplers. the Focus of This Paper is the Comparison of Three Pre-Consolidation Stress Determination Techniques, Which Were Performed on Each Specimen of the Large Sample Pool. the Methods Used Were the Casagrande Method, Strain-Energy Method, and Intersecting Tangent Method. the Implementation of These Methods Will Be Evaluated. in Addition, the Subjectivity of Each Method Will Be Addressed. the Final Results of the Techniques Will Then Be Compared and Contrasted. © 2011 ASCE

Conceptualizing a Knowledge Society in China: A Ubiquitous Network Perspective

Developing Ubiquitous Network Societies (UNS) has been a subject of investigation in last decade. Several policy and technological projects have been proposed and implemented at global level to promote ubiquitous network. This paper focuses on China’s preparation towards UNS by analyzing and evaluating the prerequisite technological developments that enable the construction of UNS. The objective of this paper is to identify the notable features of UNS in context to China. Being the nascent area of study our research approach is from technological perspective

Assessment of the Bill Emerson Memorial Cable-Stayed Bridge based on Seismic Instrumentation Data

In this study, both ambient and earthquake data measured from the Bill Emerson Memorial Cable-stayed Bridge are reported and analyzed. Based on the seismic instrumentation data, the vibration characteristics of the bridge are investigated and used to validate a three-dimensional Finite Element (3-D FE) model of the bridge structure. The 3-D model is rigorous and comprehensive, representing realistic dynamic behaviors of the bridge. It takes into account the geometric nonlinear properties caused by cable sagging and soil-foundation-structure interaction in the Illinois approach of the bridge. The FE model is successfully verified and validated by using the natural frequencies and mode shapes of the bridge extracted from the measured data. With the calibrated model, time history analyses were performed to assess the condition of the bridge structure under a postulated design earthquake. Since the FE model is developed according to as-built drawings, the calibrated model can be used as a benchmark for safety evaluation and health monitoring of the cable-stayed bridge in the future