Data Reduction And Error Analysis For The Physical Sciences

[1] Field observations of mature crustal faults suggest that slip in individual events occurs primarily within a thin shear zone, <1–5 mm, within a finely granulated, ultracataclastic fault core. Relevant weakening processes in large crustal events are therefore suggested to be thermal, and to involve the following: (1) thermal pressurization of pore fluid within and adjacent to the deforming fault core, which reduces the effective normal stress and hence also the shear strength for a given friction coefficient and (2) flash heating at highly stressed frictional microcontacts during rapid slip, which reduces the friction coefficient. (Macroscopic melting, or possibly gel formation in silica-rich lithologies, may become important too at large enough slip.) Theoretical modeling of mechanisms 1 and 2 is constrained with lab-determined hydrologic and poroelastic properties of fault core materials and lab friction studies at high slip rates. Predictions are that strength drop should often be nearly complete at large slip and that the onset of melting should be precluded over much (and, for small enough slip, all) of the seismogenic zone. A testable prediction is of the shear fracture energies that would be implied if actual earthquake ruptures were controlled by those thermal mechanisms. Seismic data have been compiled on the fracture energy of crustal events, including its variation with slip in an event. It is plausibly described by theoretical predictions based on the above mechanisms, within a considerable range of uncertainty of parameter choices, thus allowing the possibility that such thermal weakening prevails in the Earth.

/pdf/heating-and-weakening-of-faults-during-earthquake-slip-25qvhi66e0.pdf

Heating and weakening of faults during earthquake slip

Structural health monitoring (SHM) is a term increasingly used in the last decade to describe a range of systems implemented on full-scale civil infrastructures and whose purposes are to assist and inform operators about continued 'fitness for purpose' of structures under gradual or sudden changes to their state, to learn about either or both of the load and response mechanisms. Arguably, various forms of SHM have been employed in civil infrastructure for at least half a century, but it is only in the last decade or two that computer-based systems are being designed for the purpose of assisting owners/operators of ageing infrastructure with timely information for their continued safe and economic operation. This paper describes the motivations for and recent history of SHM applications to various forms of civil infrastructure and provides case studies on specific types of structure. It ends with a discussion of the present state-of-the-art and future developments in terms of instrumentation, data acquisition, communication systems and data mining and presentation procedures for diagnosis of infrastructural 'health'.

/pdf/structural-health-monitoring-of-civil-infrastructure-3bh4epxsu5.pdf

Structural health monitoring of civil infrastructure

To simulate numerically the microstructure of shear bands, the distinct element method was modified such that the effect of rolling resistance at contacts could be taken into account. To this end, the relative movement by rolling is related to the relative rotation between two particles with a common contact, which makes it possible to generalize the conservation law of angular momentum for a more general case than the moments can be transmitted through contacts. Not only the generation of large voids inside a shear band but also the high gradient of particle rotation along the shear band boundaries can be reproduced, in a manner quite similar to those of natural granular soils, when the rolling resistance at contacts is considered. The development of columns is a common feature that appears in the strain hardening process, and buckling of the columns parallels the development of shear bands. The generation of large voids and the high gradient of particle rotation are produced as a result of the buckling of the columns.

Rolling Resistance at Contacts in Simulation of Shear Band Development by DEM

This article is a personal review of the historical developments of digital image correlation (DIC) techniques, together with recent important advances and future goals. The historical developments of DIC techniques over the past 35 years are divided into a foundation-laying phase (1982–1999) and a boom phase (2000 to the present), and are traced by describing some of the milestones that have enabled new and/or better DIC measurements to be made. Important advances made to DIC since 2010 are reviewed, with an emphasis on new insights into the 2D-DIC system, new improvements to the correlation algorithm, and new developments in stereo-DIC systems. A summary of the current state-of-the-art DIC techniques is provided. Some further improvements that are needed and the future goals in the field are also envisioned.

Digital image correlation for surface deformation measurement: historical developments, recent advances and future goals

Shear bands in plane strain active tests of moist tamped and pluviated sands

A series of impulse response tests using multiple geophones was perfonned to identify anomalies in drilled shafts. Testing was performed on drilled shafts at the University of Houston NOES to detect small anomalies and at the Texas A&M University NGES to detect gross anomalies. Both sites consisted of drilled shafts constructed with carefully controlled construction procedures and included known anomalies. The results of the impulse response tests were analyzed using a new technique based on composite geophone array analysis and numerical simulations. Differences in responses depending on the placement ofthe geophone on the shaft head surface were investigated and the ability to quantify the size and location ofthe planned anomalies was evaluated. Impulse response tests performed on the drilled shafts at TexasA&M showed that detection ofsevere defects caused by dynamic load testing was enhanced by the multiple geophone approach when resonances from the shaft toe could only be detected from certain geophone locations. However, the multiple geophone approach was unsuccessful in identifying the small anomalies, 2.54 cm thick rubber inclusions, in the Houston shafts.

Anomaly Detection in Drilled Shafts

Internal bracing in conventional 2-d finite element models of deep excavations is modeled by averaging the stiffness of the internal braces over their spacing and considering the bending stiffness of the wall about its neutral axis in the plane of bending. The effects of the waler connecting the brace and wall are usually ignored. When making a 3-d simulation, each internal brace can be modeled individually. In this case, when evaluating the 3-d distribution of ground movements and structural responses, the effects of the waler should be considered. However, it is not feasible to explicitly model each waler and all the connections between the brace, waler and wall. This paper summarizes the considerations related to such simulations, presents the results of parametric studies that show the effects of sheeting flexibility parallel to the wall and compares results of 3-d finite element simulations to responses at the Ford Design Center excavation in Evanston, IL.

Representing Internal Bracing Systems in 3-D Models of Deep Excavations

Coupled deformation-pore fluid diffusion effects on the development of localized deformation in fault gouge

The initial anisotropy of natural clays can be characterized by the elastic shear moduli measured by wave propagation techniques both in situ and in the laboratory. This paper summarizes results of studies of the initial anisotropy of fresh water glacial clays from two sites in the Chicago area. Advanced cross-hole seismic tests which measure both horizontally propagating and vertically- and horizontallypolarized shear wave velocities and seismic cone penetration tests (sCPT) were performed in situ. Bender elements were used to measure propagation velocities on laboratory specimens cut from high quality block samples of soft to medium clays obtained from the excavation for the Ford Design Center project. These clays are lightly overconsolidated, supraglacial tills. Laboratory specimens of hard clay from the One Museum Park West site were obtained with a Pitcher barrel sampler; these clays are overconsolidated, basal tills. Both in situ and laboratory results for the soft to medium clays indicate that the magnitude of the shear moduli are the same in each polarized direction. These clays are slightly cross anisotropic. For the harder clays, the in situ shear moduli are larger than those measured in the laboratory, presumably as a result of the sample disturbance arising from Pitcher barrel sampling.

Elastic Cross-Anisotropy of Chicago Glacial Clays from Field and Laboratory Data

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Richard J. Finno

Author Tools

Chat about Author