A Platform for Proactive, Risk-Based Slope Asset Management, Phase II

INE/AUTC 15.0

Seismic Soil Structure Interaction Analyses of an Office Building in Oakland, California

This paper discusses soil-structure interaction (SSI) analyses for a 10-story office building with three levels of basement (10 meters) located in downtown Oakland, California. The objectives of these analyses were to assess the effects of SSI on the response of the building and to develop ground-level input earthquake motions at the base of the building for use by the project structural engineer. The SSI analyses were conducted using the two-dimensional finite element program FLUSH. The results of these analyses indicate that SSI has a negligible effect on horizontal ground motions at and near the building’s predominant period (T ~ 1.8 seconds). Minor but unfavorable SSI effects were found at higher frequencies. The effects of SSI on the vertical motions in the building were for practical purposes, negligible. Parametric studies indicate that more favorable SSI effects may have been realized if the building was surrounded by softer soils

Geotechnical physical modeling for education: Learning theory approach

Journal of Professional Issues in Engineering Education and Practice, 132(4): pp. 288-296.As physical modeling sees increasing use in geotechnical engineering education, there is a need for a strategic approach for integrating this powerful simulation technique into courses in a way that ensures the greatest benefit for students. For this reason, a learning theory approach, which recognizes the natural learning cycle of students, has been developed. The approach is based on a modified version of the learning theorist David Kolb’s “theory of experiential learning.” The approach emphasizes a variety of learning styles and thus is appealing to a broad range of students. The approach is relatively easy to apply to traditional geotechnical engineering coursework and requires only a modest effort to adopt. It is expected that by using this approach when designing course modules, instructors can increase the likelihood that comprehensive learning will take place. While this paper focuses on physical modeling for geotechnical engineering, the approach presented here has educational applications to an array of other civil engineering topics

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

Investigation of 1-g similitude laws by “modeling-of-models”

Paper presented at Geo-Denver 2007: New Peaks in Geotechnics. Denver, CO.This paper presents the results of a “modeling-of-models” laboratory exercise conducted in a 1-g environment to investigate the applicability and validity of established similitude laws. The study, which was performed under static condition, considers the behavior of cohesive model slopes at small (stiffness) and large strains (failure). The test program involved three small-scale model slopes tested under different geometry scaling factors. The models were comprised of an artificial, fully saturated "model" clay (3 parts kaolinite to 1 part bentonite). The results indicate that for fully saturated cohesive soils tested under undrained conditions, similitude laws are valid for static conditions provided that three dimensional effects and boundary conditions are properly accounted for

Unmanned Aircraft System Assessments of Landslide Safety for Transportation Corridors

An assessment of unmanned aircraft systems (UAS) concluded that current, off-the-shelf UAS aircraft and cameras can be effective for creating the digital surface models used to evaluate rock-slope stability and landslide risk along transportation corridors. The imagery collected with UAS can be processed using a photogrammetry technique called Structure-from-Motion (SfM) which generates a point cloud and surface model, similar to terrestrial laser scanning (TLS). We treated the TLS data as our control, or “truth,” because it is a mature and well-proven technology. The comparisons of the TLS surfaces and the SFM surfaces were impressive – if not comparable is many cases. Thus, the SfM surface models would be suitable for deriving slope morphology to generate rockfall activity indices (RAI) for landslide assessment provided the slopes. This research also revealed that UAS are a safer alternative to the deployment and operation of TLS operating on a road shoulder because UAS can be launched and recovered from a remote location and capable of imaging without flying directly over the road. However both the UAS and TLS approaches still require traditional survey control and photo targets to accurately geo-reference their respective DSM.List of Figures ...................................................................................................... vi List of Abbreviations ......................................................................................... vii Acknowledgments ................................................................................................ x Executive Summary ............................................................................................. xi CHAPTER 1 INTRODUCTION .......................................................................... 1 CHAPTER 2 LITERATURE REVIEW ................................................................ 4 2.1 Landslide Hazards .................................................................................... 4 2.2 Unmanned Aircraft Systems Remote Sensing.......................................... 6 2.3 Structure From Motion (SfM) .................................................................. 7 2.4 Lidar terrain mapping ............................................................................... 8 CHAPTER 3 STUDY SITE/DATA .................................................................. 11 CHAPTER 4 METHODS ................................................................................ 13 4.1 Data Collection ............................................................................................. 13 4.1.1 Survey Control ..................................................................................... 14 4.1.2 TLS Surveys ........................................................................................ 16 4.1.3 UAS Imagery ....................................................................................... 17 4.1.4 Terrestrial Imagery Acquisition ........................................................... 19 4.2 Data Processing ............................................................................................ 20 4.2.1 Survey Control ..................................................................................... 20 4.2.2 TLS Processing .................................................................................... 20 4.2.3 SfM Processing .................................................................................... 21 4.2.4 Surface Generation .............................................................................. 22 4.3 Quality Evaluation ........................................................................................ 23 4.3.1 Completeness ....................................................................................... 23 4.3.2 Data Density/Resolution ...................................................................... 23 4.3.3 Accuracy Assessment .......................................................................... 23 4.3.2 Surface Morphology Analysis ............................................................. 24 4.2.6 Data Visualization ............................................................................... 25 CHAPTER 5 RESULTS ................................................................................. 27 v 5.1 UTIC DSM evaluation.................................................................................. 27 5.1.1 Completeness evaluation ..................................................................... 28 5.1.2 Data Density Evaluation ...................................................................... 29 5.1.3 Accuracy Evaluation............................................................................ 30 5.2 Geomorphological Evaluation ...................................................................... 32 CHAPTER 6 DISCUSSION ............................................................................ 35 6.1 Evaluation of UAS efficiencies .................................................................... 35 6.2 DSM quality and completeness .................................................................... 37 6.3 Safety and operational considerations .......................................................... 37 CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS ................................ 40 7.1 Technology Transfer..................................................................................... 41 7.1.1 Publications ......................................................................................... 41 7.1.2 Presentations ........................................................................................ 42 7.1.3 Multi-media outreach .......................................................................... 43 6.4 Integration of UAS and TLS data ................................................................. 44 REFERENCES .............................................................................................. 4

Observations of Site Amplification and Liquefaction in the Jun 23, 2001, Southern Peru Earthquake

The Mw 8.4 Southern Peru Earthquake of June 23, 2001 caused extensive damage in a widespread area in southern Peru and northern Chile, including several important population centers. Damage in some of these cities was correlated with local soil conditions and topography, suggesting the influence of local site amplification effects in damage distributions. The earthquake caused numerous instances of other types of geotechnical related ground failures, including liquefaction and lateral spreads in river valleys, seismic compression of highway fills, and slope failures. This work focuses on case histories documenting site amplification and liquefaction in the Southern Peru earthquake. Among the liquefaction events observed in this earthquake, the liquefaction of a heap-leach pad is the first reported failure of its type in a seismic event

Street View Data Collection Design for Disaster Reconnaissance

Over the last decade, street-view type images have been used across disciplines to generate and understand various place-based metrics. However efforts to collect this data were often meant to support investigator-driven research without regard to the utility of the data for other researchers. To address this, we describe our methods for collecting and publishing longitudinal data of this type in the wake of the COVID-19 pandemic and discuss some of the challenges we encountered along the way. Our process included designing a route taking into account both broad area canvassing and community capitals transects. We also implemented procedures for uploading and publishing data from each survey. Our methods successfully generated the kind of longitudinal data that can be beneficial to a variety of research disciplines. However, there were some challenges with data collection consistency and the sheer magnitude of data produced. Overall, our approach demonstrates the feasibility of generating longitudinal street-view data in the wake of a disaster event. Based on our experience, we provide recommendations for future researchers attempting to create a similar data set.Comment: 11 pages, 2 figures, 1 tabl

Immediate and time dependent compression of tire derived aggregate

Journal of Geotechnical and Geoenvironmental Engineering, 133(3): pp. 245-256.This paper examines immediate and time-dependent compression of tire derived aggregate (TDA)and TDA-soil composites. To accommodate large particle sizes, modified experimental devices were developed and used to test tire chips and tire shreds. Immediate compression of TDA, which results almost entirely from the reduction of pore volume, increases with TDA content and tire particle size. The secant constrained modulus (Msec ) of TDA defined over the stress range of 0–50 kPa varied from a low of 255 kPa (100% tire shreds )to a high of 1,320 kPa (50% tire chips). A characteristic relationship between strain and time exists for TDA and TDA composites under one-dimensional confined compression. Time-dependent deformation is well described by the modified secondary compression index (Cae) which ranged from 0.0010 (50% tire chips) to 0.0074 (100% tire chips). Time-dependent deformation was inversely proportional to sand content, with the most significant changes resulting from the addition of 15% sand. Both applied stress and tire particle size appear to have a negligible effect on time-dependent compression of TDA. Based on the findings of this study it is recommended that practitioners assess time-dependent settlement when designing a TDA structure and if necessary incorporate design features to accommodate these settlements