The Response of Frozen Soils to Vibratory Loads

The Response of Frozen Soils to Vibratory Loads
Author: Henry W. Stevens
Publisher:
Total Pages: 112
Release: 1975
Genre: Frozen ground
ISBN:

This study was conducted to provide reliable values of the stiffness and damping properties of frozen soils subjected to vibratory loads and to define the significant factors affecting these parameters. A laboratory test was conducted on prepared specimens of frozen soils wherein a right circular cylinder was subjected to steady-state sinusoidal vibration. The material was considered to be linearly viscoelastic. Analysis of test data based on one-dimensional wave propagation yielded the complex Young's modulus, the complex shear modulus, the phase velocity of wave propagation, the shear velocity, the damping property expressed as the angle representing time lag between stress and strain, an attenuation coefficient, and a complex Poisson's ratio. The frequency of vibration was varied from 500 to 10,000 Hz, and the peak dynamic stress was varied from 0.1 to 5.0 psi. Specimens were remolded or cored in-situ, frozen, and tested at temperatures of 0, +15 and +25 deg F.A few tests were conducted on identical soils nonfrozen. Tests results from a limited number of tests on selected soils indicate that the stiffness of these soils varies with the volume of ice/volume of soil ratio, and that ice is less stiff than saturated frozen soils. Frozen soils have stiffnesses up to 100 times those of identical soil nonfrozen. Depending upon the degree of ice saturation, the stiffness of non-saturated frozen soils varies from that of the saturated soils to nearly that of the nonfrozen soils. Stiffness increases with decreasing temperature but the rate is relatively low. As temperature rises and approaches the freezing point, stiffness abruptly decreases.

Ground Freezing

Ground Freezing
Author: Hans L. Jessberger
Publisher: Elsevier
Total Pages: 559
Release: 2012-12-02
Genre: Science
ISBN: 0444601961

Developments in Geotechnical Engineering Volume 26: Ground Freezing presents the proceedings of the First International Symposium on Ground Freezing, held in Bochum, Germany on March 8-10, 1978. It summarizes progress in the application of the ground freezing technique in geotechnical engineering, with a focus on engineering with frozen soils and related frost research problems. It includes papers that discuss phase transformation of water, thermodynamics, heat and mass transfer, and mathematical models. The laboratory and theoretical studies of thermophysical and mechanical properties are discussed as well. Organized into 43 chapters, this volume begins with an overview of the freezing and thawing of soils, earth, and rock, and the engineering applications of the favorable properties of frozen ground. It then discusses the mechanical properties of artificially frozen soil for construction purposes, the principles of mechanical and thermal behavior of frozen soil, and the design and calculation of frozen soil-structures. Furthermore, it explains the calculation and dimensioning of refrigeration plants and monitoring of frost penetration. The methods and instrumentation for determining the locations of boundaries of frozen soils and the factors affecting the formation of soil cryogenic textures upon artificial active and passive soil freezing are described. The book also details the influence of salts in the pore water in freezing soils and explains how clay microstructure affects the amount of unfrozen water. In addition, it presents the physicomechanical and thermomechanical properties of frozen coarse-grained soil with sandy clay aggregate. This book will be a valuable source of information for scientists and engineers.

Dynamics of Freezing-Thawing Soil around Subway Shield Tunnels

Dynamics of Freezing-Thawing Soil around Subway Shield Tunnels
Author: Zhen-Dong Cui
Publisher: Springer Nature
Total Pages: 199
Release: 2020-05-18
Genre: Technology & Engineering
ISBN: 9811543429

This book addresses development laws for axial strain and excess pore water pressure in silty clay around subway shield tunnels before and after freezing-thawing when subjected to subway loading, as well as the effect of freezing-thawing on the dynamic parameters of silty clay, including the dynamic modulus and damping ratio, introducing readers to the design and construction of bypasses in subway tunnels with the artificial freezing method. On this basis, it then studies the microstructures of silty clay before and after freezing-thawing cyclic loading by means of scanning electron microscope tests and mercury intrusion porosimetry tests. Lastly, the book presents a numerical simulation of the dynamics of silty clay around subway tunnels before and after thawing. Given its scope, it offers a valuable reference guide for construction researchers and designers alike, as well as senior undergraduate and graduate students at colleges and universities.