Estimation of Liquefaction-Induced Ground Settlement (Case Studies)

Over the past decade, the focus of liquefaction engineering began to shift towards assessment of the consequences of liquefaction with respect to the seismic performance of engineered structures and facilities, which requires accurate and reliable tools for prediction of ground deformations over the small to moderate range. Promising new predictive tools are evolving. These include simplified, empirical tools as well as sophisticated analytical and constitutive models. Recently, a high quality laboratory testing program consisting of undrained, cyclic simple shear testing on fully-saturated samples of Monterey No. 0/30 sand was completed at U.C. Berkeley. As a result, a new semiempirical procedure was proposed for predicting post-liquefaction volumetric reconsolidation ground settlements in essentially level ground (α ≈ 0 conditions). This new procedure also includes modification for predicting liquefaction-induced ground settlement in sloping or near free-face ground (α ≠ 0 conditions). The new procedure was shown to perform well for a suite of field performance case histories with small-to-moderate ground settlements, comparing with existing semi-empirical engineering tools for estimating liquefaction-induced ground deformations

Compaction-Induced Distress of a Long-Span Culvert Overpass Structure

Compaction of backfill produces soil stresses and earth pressures which are not amenable to analysis by conventional methods. These compaction-induced earth pressures can produce stresses and deformations in flexible buried culvert structures which may significantly affect the stability and performance of these structures. This paper presents the results of a study in which deformations of a long-span flexible metal culvert were measured during carefully monitored backfill operations. These field measurements were then compared with the results of finite element analyses in order to investigate (a) the influence of compaction effects on culvert stresses and deformations, and (b) the ability of recently developed finite element analysis procedures to accurately model these compaction effects. The structure being monitored suffered excessive and unacceptable deformations which were shown to be primarily the result of compaction effects; these were well modelled by the analyses performed

Integrating food security into public health and provincial government departments in British Columbia, Canada

Food security policy, programs, and infrastructure have been incorporated into Public Health and other areas of the Provincial Government in British Columbia, including the adoption of food security as a Public Health Core Program. A policy analysis of the integration into Public Health is completed by merging findings from 48 key informant interviews conducted with government, civil society, and food supply chain representatives involved in the initiatives along with relevant documents and participant/direct observations. The paper then examines the results within the context of historic and international trends and theoretical models of food policy, community food security, and applied policy research. Public Health re-emerged as a driver of food security in BC—both as a key player and in positing the public’s health as a driver in food security and food systems. While Public Health’s lead role supported an increase in legitimacy for food security in BC, interviewees described a clash of cultures between Public Health and civil society. The clash of cultures occurred partly as a result of Public Health’s limited food security mandate and top down approach. Consequently civil society voice at the provincial level was marginalized. A social policy movement toward a new political paradigm—regulatory pluralism—calls for greater engagement of civil society, and for all sectors to work together toward common goals. A new, emerging policy map is proposed for analyzing the dynamics of food security and health promotion initiatives in BC

Shaking Table Experiment of a Model Slope Subjected to a Pair of Repeated Ground Motions

This paper describes the third of a series of six shaking table experiments conducted as part of ongoing research to evaluate the accuracy and applicability of the Newmark (1965) procedure for computing seismically induced deformation in slopes. A cohesive model slope was shaken by two identical test motions in succession, mimicking a situation that commonly occurs when a preexisting landslide is subjected to strong earthquake shaking. Back analyses of the tests showed that the Newmark (1965) formulation provided moderately accurate estimates of the measured permanent deformations (within 40% to 85% of the maximum measured displacement). The accuracy of the Newmark (1965) formulation was greatest when displacement-dependent degrading yield acceleration was used to model the soil’s transition from peak to residual shear strength. The Newmark analyses were most reliable for the second test that experienced relatively large deformations, and thus where the sliding resistance was controlled by post-peak to residual strength

The Kettleman Hills Landfill Failure: A Retrospective View of the Failure Investigations and Lessons Learned

The sliding stability failure of the Kettleman Hills waste landfill focused attention on several issues related to the safe design and filling of waste repositories, including low strengths between geosynthetic material interfaces in composite liner systems and low interface strength between compacted clay and smooth geomembranes. Waste placement plans must be carefully developed to insure an adequate factor of safety against sliding at all stages of filling. Because of assumptions and uncertainties that remained following the initial failure investigation, model tests, at a scale of 1:150, were done. These tests reproduced the field failure very well and provided insights into the failure mechanisms. A three-dimensional method for stability analysis gave results in close agreement with field observations and the results of a subsequent detailed failure investigation done by others (Byrne et al., 1992). Those special cases of landfill geometry and liner properties for which the 3D stability may be more critical than that computed using usual 2D methods of analysis could then be determined

Brief Note Surface Charge Determination of Proteus Mirabilis Exposed to Carbenicillin

Author Institution: Division of Infectious Diseases, Department of Medicine, The Ohio State University College of Medicin

Response of Two Dams in the 1987 Whittier Narrows Earthquake

The 1987 Whittier Narrows earthquake (ML = 5.9) shook two dams, the Puddingstone and Cogswell dams, which were instrumented as part of the California Strong Motion Instrumentation Program (CSMIP). The resulting recorded accelerograms provided a valuable opportunity to investigate and evaluate the accuracy and reliability of conventional geotechnical procedures for evaluation of dynamic response characteristics of earth and rockfill dams. This paper presents the results of these studies, which provide insight regarding current techniques for dynamic soil property evaluation and the applicability of one- and two-dimensional analytical procedures to evaluation of the dynamic response of these types of dams

Liquefaction of Soils in the 1989 Loma Prieta Earthquake

The Loma Prieta Earthquake of October 17, 1989 was the most costly single natural disaster in U.S. history, resulting in losses of $7 to$9 billion, and claiming 63 lives. These damages were concentrated mainly at a number of distinct sites comprising a relatively small fraction of the affected region, as local site conditions and related geotechnical factors exerted a major influence on damage patterns and loss of life in this catastrophic event. This paper discusses one of these geotechnical factors, the widespread occurrence of soil liquefaction during the earthquake, as well as the associated damages and the resulting lessons learned. Additional significant geotechnical factors which exerted a strong influence on damage patterns during this event, including site-dependent dynamic response and seismically-induced slope instability, are discussed in companion papers in these proceedings

Ground Motions from the Northridge Earthquake

The magnitude, duration and frequency content of ground motions from the Northridge Earthquake are analyzed and compared to predictive relationships typically used in engineering design and to the 1994 Uniform Building Code. The effect of geologic conditions on localized damage patterns is shown to be important for this earthquake, even though many of the sites within the affected region are stiff soil sites classified as UBC sites S1 or S2