The Importance of Mineralogy and Grain Compressibility in Understanding Field Behavior of Failures

In this paper, we examine the role of grain mineralogy and compressibility, sample preparation, and shear strain/displacement levels on the shearing behavior of sands using undrained triaxial and constant volume ring shear tests in an attempt to explain some discrepancies observed between field and laboratory behavior. As expected, preparation by moist tamping can produce specimens that are contractive throughout shear, while counterparts prepared using pluviation exhibit dilative behavior at intermediate shear strain/displacement levels (i.e., after initial yield). However, both triaxial and ring shear tests illustrate that some sands consisting of more compressible minerals can exhibit entirely contractive behavior regardless of the sample preparation method. These preliminary tests suggest that laboratory testing of pure quartz sands may result in potentially misleading conclusions regarding the field behavior of mixed mineral soils involved in many liquefaction flow failures and long run-out landslides. Furthermore, grain crushing at larger displacements (larger than those that can be achieved in the triaxial device) results in net contractive response regardless of the sample preparation method or the grain mineralogy. Grain crushing has been observed in shear zones formed during a few well-documented long run-out landslides. The combination of these factors: grain mineralogy and compressibility, particle damage and crushing, and shear zone formation may help to explain some discrepancies observed between field and laboratory behavior of sands

Liquefaction Analysis of Lower San Fernando Darn Using Strength Ratios

Olson (2000) evaluated 33 liquefaction flow failure case histories to assess the yield strength ratio and liquefied strength ratio mobilized during the failures. Using back-analysis procedures developed by Olson (2000), yield and liquefied shear strengths are shown to be proportional to the pre-failure vertical effective stress and are related to standard and cone penetration resistances. This paper examines the triggering of liquefaction and subsequent flow failure of Lower San Fernando Dam using yield and liquefied strength ratios. The yield strength ratio is used to correctly predict the occurrence of liquefaction in the upstream hydraulic fill of the dam, and the liquefied shear strength ratio is used to correctly predict the subsequent flow failure of the upstream slope. The relationships for the yield and liquefied ratios are presented, and their application to existing or new structures is illustrated using the Lower San Fernando Dam case history

The Effects of Nutrition Package Claims, Nutrition Facts Panels, and Motivation to Process Nutrition Information on Consumer Product Evaluations

In a laboratory experiment using a between-subjects design, the authors examine the effects on nutrition and product evaluations of nutrition claims made (e.g., 99% fat free; low in calories ) on a product package, product nutrition value levels, and enduring motivation to process nutrition information. Enduring motivation is shown to moderate the effects of product nutrition value on consumer evaluations. Also, nutrition claims interact with product nutrition value in affecting consumer perceptions of manufacturer credibility. Given the availability of nutrient levels in the Nutrition Facts panel on the back of the mock package, nutrition claims on the front of the package generally did not affect positively consumers\u27 overall product and purchase intention evaluations. The authors discuss some implications of these findings, suggestions for further research, and study limitations

Landslide Stabilization at Missouri Route K Bridge over Blackwater River

In May 2002, a landslide on the south bank of the Blackwater River damaged the Missouri Route K bridge that crosses it. A flood on the river triggered the landslide. Based on the field investigation and stability back-analysis, it appeared that the landslide actually consisted of two separate slides – a shallow slide triggered by rapid drawdown of the river and a deep slide triggered by artesian water pressures in a subsurface gravel layer. A rock berm that was keyed into the gravel was constructed to stabilize the slope. The rock toe berm was designed to resist both the shallow and deep slide by providing weight to the slope to prevent a rapid drawdown failure and providing a drainage outlet to relieve artesian pressures in the gravel layer

Geotechnical Earthquake Engineering for the Great River Bridge

The proposed Great River Bridge is a 1400-foot long cable-stay structure that will be constructed over the Mississippi River between Desha County, Arkansas and Bolivar County, Mississippi. Including the bridge approach structures and approach embankments, the total structure length is approximately 23,500 feet. Seismic issues have controlled most of the structural design. Design ground motions for three typical subsurface profiles were developed and resulted in near-surface peak accelerations between 0.23 and 0.26g. Level ground liquefaction analyses indicated widespread liquefaction in an abandoned channel of the river and sporadic liquefaction elsewhere. Seismic slope stability and lateral spreading analyses indicated minor displacements at the approach embankments, the Arkansas levee, and the Mississippi riverbank; moderate displacements at the Mississippi levee; and major displacements at a 25-foot high natural terrace and the Arkansas riverbank. Conceptual liquefaction mitigation/soil improvement options were investigated

Presynchronizing PGF2α and GnRH injections before timed artificial insemination CO-Synch + CIDR program

Fixed-time artificial insemination is an effective management tool that reduces the labor associated with more conventional artificial insemination programs requiring detection of estrus. The 7-day CO-Synch + controlled internal drug release (CIDR) insert protocol has been shown to effectively initiate estrus and ovulation in cycling and non-cycling suckled beef cows, producing pregnancy rates at or greater than 50% in beef cows. The gonadotropin-releasing hormone (GnRH) injection that begins the CO-Synch + CIDR program initiates ovulation in a large proportion of cows, particularly anestrous cows. The CIDR, which releases progesterone intravaginally, prevents short estrous cycles that usually follow the first postpartum ovulation in beef cows. Our hypothesis was that inducing estrus with a prostaglandin injection followed 3 days later with a GnRH injection, 7 days before applying the 7-day CO-Synch + CIDR protocol, might increase the percentage of cycling cows that would exhibit synchronous follicular waves after the onset of the CO-Synch + CIDR protocol. We also hypothesized that the additional GnRH injection would increase the percentage of anestrous cows that would ovulate, thereby increasing pregnancy outcomes

Multimodal Data at Signalized Intersections: Strategies for Archiving Existing and New Data Streams to Support Operations and Planning & Fusion and Integration of Arterial Performance Data

There is a growing interest in arterial system management due to the increasing amount of travel on arterials and a growing emphasis on multimodal transportation. The benefits of archiving arterial-related data are numerous. This research report describes our efforts to assemble and develop a multimodal archive for the Portland-Vancouver region. There is coverage of data sources from all modes in the metropolitan region; however, the preliminary nature of the archiving process means that some of the data are incomplete and samples. The arterial data sources available in the Portland-Vancouver region and that are covered in this report include data for various local agencies (City of Portland, Clark County, WA, TriMet and C-TRAN) covering vehicle, transit, pedestrian, and bicycle modes. We provide detailed descriptions of each data source and a spatial and temporal classification. The report describes the conceptual framework for an archive and the data collection and archival process, including the process for extracting the data from the agency systems and transferring these data to our multimodal database. Data can be made more useful though the use of improved visualization techniques. Thus as part of the project, a number of novel, online visualizations were created and implemented. These graphs and displays are summarized in this report and example visualizations are shown. As with any automated sensor system, data quality and completeness is an important issue and the challenge of automating data quality is large. Preliminary efforts to validate and monitor data quality and automate data quality processing are explored. Finally, the report presents efforts to combine transit and travel time data and signal timing and vehicle count data to generate some sample congestion measures

Using Tactile Pressure Sensors to Measure Lateral Spreading Induced Earth Pressures Against a Large, Rigid Foundation

Two centrifuge tests were performed at the NEES facility at Rensselaer Polytechnic Institute (RPI) to observe lateral earth pressures mobilized against a rigid foundation element during liquefaction-induced lateral spreading, as part of a larger NEESR study aimed at developing novel approaches to mitigate the effects of seismically-induced ground failures on large, rigid foundation elements. Models were constructed in a laminar box to allow unimpeded downslope soil displacement, and the sand in the model was liquefied during the centrifuge test. Lateral pressures prior to, during, and after shaking and liquefaction were directly measured using a novel device: tactile pressure sensors. Prior to testing the production models, several 1g and centrifuge experiments were conducted to determine whether the tactile pressure sensors would accurately measure pressures. Using the tactile pressure sensor and configuration described in this paper, geostatic pressures measured prior to the shaking agreed well with the anticipated theoretical at-rest earth pressures. In this paper, we describe these initial tests, the challenges that were encountered, methods employed to overcome these challenges, and the production centrifuge tests

Degenerate dispersive equations arising in the study of magma dynamics

An outstanding problem in Earth science is understanding the method of transport of magma in the Earth's mantle. Models for this process, transport in a viscously deformable porous media, give rise to scalar degenerate, dispersive, nonlinear wave equations. We establish a general local well-posedness for a physical class of data (roughly $H^1$) via fixed point methods. The strategy requires positive lower bounds on the solution. This is extended to global existence for a subset of possible nonlinearities by making use of certain conservation laws associated with the equations. Furthermore, we construct a Lyapunov energy functional, which is locally convex about the uniform state, and prove (global in time) nonlinear dynamic stability of the uniform state for any choice of nonlinearity. We compare the dynamics to that of other problems and discuss open questions concerning a larger range of nonlinearities, for which we conjecture global existence.Comment: 27 Pages, 7 figures are not present in this version. See http://www.columbia.edu/~grs2103/ for a PDF with figures. Submitted to Nonlinearit