Soil Dynamics and Special Design Aspects

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MIL-HDBK-1007/3
15 November 1997

Supersedes NAVFAC DM 7.3, April 1983

• BASIC DYNAMICS
  • Vibratory Motions
  • Mass, Stiffness, Damping
  • Amplification Function
  • Earthquake Ground Motions
• SOIL PROPERTIES
  • Soil Properties for Dynamic Loading
  • Types of Soils
  • Dry and Partially Saturated Cohesionless Soils
  • Saturated Cohesionless Soils
  • Saturated Cohesive Soils
  • Partially Saturated Cohesive Soils
  • Measuring Dynamic Soil Properties
  • Field Measurements of Dynamic Modulus
  • Laboratory Measurement of Dynamic Soil Properties
• MACHINE FOUNDATIONS
  • Analysis of Foundation Vibration
  • Machine Foundations
  • Impact Loadings
  • Characteristics of Oscillating Loads
  • Method of Analysis
  • Dynamic Soil Properties Design to Avoid Resonance
  • High-Speed Machinery
  • Low-Speed Machinery
  • Coupled Vibrations
  • Effect of Embedment
  • Proximity of a Rigid Layer
  • Vibration for Pile Supported Machine
  • Foundation Bearing Capacity and Settlements Vibration Transmission, Isolation, and Monitoring
  • Vibration Transmission
  • Vibration and Shock Isolation
  • Vibration Monitoring
• DYNAMIC AND VIBRATORY COMPACTION
  • Soil Densification
  • Vibro-Densification
  • Dynamic Compaction Applications of Vibroflotation
  • Compaction Grout
• PILE DRIVING RESPONSE
  • Wave Equation Analysis
  • Wave Propagation in Piles
  • Wave Equation Application
  • Dynamic Testing of Piles
  • Results From Dynamic Testing
  • Pile Dynamic Measurement Applications
  • Apparatus for Applying Impact Force
  • Impact Force Application
  • Apparatus for Obtaining Dynamic Measurement
  • Signal Transmission
  • Apparatus for Recording, Reducing, and Displaying Data

• EARTHQUAKE, WAVES, AND RESPONSE SPECTRA
  • Earthquake Mechanisms
  • Wave Propagation
  • The Response Spectrum
• SITE SEISMICITY
  • Site Seismicity Study
  • Ground Motion Estimates Analysis Techniques
• SEISMIC SOIL RESPONSE
  • Seismic Response of Horizontally Layered Soil Deposits
  • Evaluation Procedure Analysis Using Computer Program
• DESIGN EARTHQUAKE
  • Design Parameters
  • Factors Affecting Ground Motion
  • Ground Motion Parameters
  • Site Specific Studies
  • Earthquake Magnitude
  • Design Earthquake Magnitude
  • Selection of Design Earthquake
  • Intensity Peak
  • Horizontal Ground Acceleration
  • Seismic Coefficients
  • Magnitude and Intensity Relationships
  • Reduction of Foundation Vulnerability to Seismic Loads
• SEISMIC LOADS ON STRUCTURES
  • Earthquake Induced Loads
  • Foundation Loads
  • Wall Loads
  • Base Shear
• LIQUEFACTION AND LATERAL SPREADING
  • Liquefaction Considerations
  • Factors Affecting Liquefaction
  • Evaluation of Liquefaction Potential
  • Simplified Empirical Methods
  • Peak Horizontal Acceleration
  • Laboratory Tests and Site Response
  • Method Slopes
  • Pseudostatic Design
  • Strain Potential Design
  • Lateral Spreading From Liquefaction
  • Lateral Deformation
  • Evaluation Procedure
  • Application
• FOUNDATION BASE ISOLATION
  • Seismic Isolation Systems
  • System Definitions
  • Passive Control Systems
  • Active Control Systems
  • Hybrid Control Systems
  • Mechanical Engineering Applications
  • Historical Overview of Building Applications
  • Design Concept
  • Device Description
  • Elastometer Systems
  • Sliding System
  • Hybrid Systems
  • Application
  • Examples of Applications

• SEISMIC DESIGN OF ANCHORED SHEET PILE WALLS
  • Design of Sheet Pile Walls for Earthquake
  • Design Procedures
  • Example Computation
  • Anchorage System
  • Ground Anchors
  • Displacement of Sheet Pile Walls
• STONE COLUMNS AND DISPLACEMENT PILES
  • Installation of Stone Columns
  • Parameters Affecting Design Consideration
  • Soil Density
  • Coefficient of Permeability
  • Coefficient of Volume Compressibility
  • Selection of Gravel Material
  • Vibro-Replacement (Stone Columns)
  • Vibroflotation and Vibro-Replacement
• DYNAMIC SLOPE STABILITY AND DEFORMATIONS
  • Slope Stability Under Seismic Loading
  • Seismically Induced Displacement
  • Slopes Vulnerable to Earthquakes
  • Deformation Prediction From Acceleration Data
  • Computation Method
  • Sliding Rock Analogy

Soil Dynamics

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Also available: Software for Soil Dynamics (zip format, Windows)

Arnold Verruijt
Univerisity of Delft, The Netherlands

A complete treatment on this subject, whose coverage in the literature is woefully inadequate. Topics include the following:

• Vibrating Systems
• Theory of Consolidation
• Plane Waves in Porous Media
• Waves in Piles
• Earthquakes in Soft Layers
• Cylindrical Waves
• Spherical Waves
• Elastostatics of a Half Space
• Elastodynamics of a Half Space
• Foundation Vibrations
• Moving Loads on an Elastic Half Plane

We also offer for download the software that accompanies the text.

Development of Improved Procedures for Seismic Design of Buried and Partially Buried Structures

Linda Al Atik and Nicholas Sitar
Department of Civil and Environmental Engineering
University of California, Berkeley
PEER Report 2007/06
June 2007

Two sets of dynamic centrifuge model experiments were performed to evaluate the magnitude and distribution of seismically induced lateral earth pressures on retaining structures that are representative of designs currently under consideration by the Bay Area Rapid Transit (BART) and the Valley Transportation Authority (VTA). Two U-shaped cantilever retaining structures, one flexible and one stiff, were used to model the prototype structures, and dry medium-dense sand at 61% and 72% relative density was used as backfill.

The results of the centrifuge experiments show that the maximum dynamic earth pressure increases with depth and can be reasonably approximated by a triangular distribution analogous to that used to represent static earth pressure. In general, the magnitude of the seismic earth pressure depends on the magnitude and intensity of shaking, the density of the backfill soil, and the flexibility of the retaining walls. The resulting relationship between the seismic earth pressure coefficient increment (!KAE) and PGA suggests that seismic earth pressures can be neglected at accelerations below 0.3 g. This is consistent with the observations and analyses performed by Clough and Fragaszy (1977) and Fragaszy and Clough (1980), who concluded that conventionally designed cantilever walls with granular backfill could reasonably be expected to resist seismic loads at accelerations up to 0.5 g.

Conventional seismic design procedures based on the Mononobe and Okabe work that are currently in use were found to provide conservative estimates of the seismic earth pressures and the resulting dynamic moments. Specifically, the BART design criterion for rigid walls appears amply conservative, especially if the normal factors of safety are taken into account. The BART design criterion for flexible walls appears to be somewhat unconservative for loose backfill. However, considering the various factors of safety present in the conventional design it may in fact contain an appropriate level of conservatism. An important contribution to the overall moment acting on the wall is the mass of the wall itself. The data from the centrifuge experiments suggest that this contribution may be as much as 25%.

Given that the conventional analyses methods tend to give adequately conservative results without the separate consideration of the wall inertial effects, the contribution of seismic earth pressures to the overall moment acting on the retaining structures is apparently routinely overestimated. Further analyses are needed to fully evaluate the impact of this observation on the overall design.

Dynamic Bridge Substructure Evaluation and Monitoring

Larry D. Olson, P.E.
FHWA-RD-03-089
September 2005

This research project was funded to investigate the possibility that, by measuring and modeling the dynamic response characteristics of a bridge substructure, it might be possible to determine the condition and safety of the substructure and identify its foundation type (shallow or deep). Determination of bridge foundation conditions with this approach may be applied to quantify losses in foundation stiffness caused by earthquakes, scour, and impact events. Identification of bridge foundation type may be employed to estimate bridge stability and vulnerability under dead and live load ratings, particularly for unknown bridge foundations.

Effects of Void Redistribution on Liquefaction-Induced Ground Deformations in Earthquakes:
A Numerical Investigation

Marmood Seid-Karbasi
University of British Columbia (Vancouver)
March 2009

Liquefaction-induced ground failure continues to be a major component of earthquake related damages in many parts of the world. Experience from past earthquakes indicates lateral spreads and flow slides have been widespread in saturated granular soils in coastal and river areas. Movements may exceed several meters even in very gentle slopes. More interestingly, failures have occurred not only during, but also after earthquake shaking.

The mechanism involved in large lateral displacements is still poorly understood. Sand deposits often comprise of low permeability sub-layers e.g., silt seams. Such layers form a hydraulic barrier to upward flow of water associated with earthquake-induced pore pressures. This impedance of flow path results in an increase of soil skeleton volume (or void ratio) beneath the barrier. The void redistribution mechanism as the focus of this study explains why residual strengths from failed case histories are generally much lower than that of laboratory data based on undrained condition.

A numerical stress-flow coupled procedure based on an effective stress approach has been utilized to investigate void redistribution effects on the seismic behavior of gentle sandy slopes. This study showed that an expansion zone develops at the base of barrier layers in stratified deposits subjected to cyclic loading that can greatly reduce shear strength and results in large deformations. This mechanism can lead to a steady state condition within a thin zone beneath the barrier causing flow slide when a threshold expansion occurs in that zone. It was found that contraction and expansion, respectively at lower parts and upper parts of a liquefiable slope with a barrier layer is a characteristic feature of seismic behavior of such deposits. A key factor is the pattern of deformations localized at the barrier base, and magnitude that takes place with some delay. In this thesis, a framework for understanding the mechanism of large deformations, and a practical approach for numerical modeling of flow slides are presented.

The study was extended to investigate factors affecting the seismic response of slopes, including: layer thickness, barrier depth and thickness, ground inclination, permeability contrast, base motion characteristics and soil consistency.

Another finding of this study was that a partial saturation condition results in delay in excess pore pressure rise, and this factor may be responsible for the controversial behavior of the Wildlife Liquefaction Array, California (USA) during the 1987 Superstition earthquake.

It was demonstrated that seismic drains are a promising measure to mitigate the possible devastating effects of barrier layers.

A Frequency-Dependent Soil Propagation Model

Hal Amick
Colin Gordon & Associates, San Mateo, California USA
July 1999

Vibration analyses of advanced technology facilities typically must consider frequency as well as amplitude of vibration. A soil propagation model is proposed which will allow the use of site-specific, measurable, frequency dependent attenuation characteristics. A method is given which allows in-situ determination of those frequency-dependent properties. This approach is applied to the estimation of setback distances for various items of construction equipment at a particular site.

Geotechnical Earthquake Engineering for Highways

Volume 1

Volume 2

FHWA-SA-97-076
May 1997

This document provides information on how to apply principles of geotechnical earthquake engineering to planning, design, and retrofit of highway facilities. Geotechnical earthquake engineering topics discussed in this document include:

• deterministic and probablistic seismic hazard assessment;
• evaluation of design ground motions;
• seismic and site response analyses;
• evaluation of liquafaction potential and seismic settlements;
• seismic slope stability and deformation analyses; and
• seismic design of foundations and retaining structures

Included are basic principles and analyses, with reference to where detailed information on these analysis can be obtained.

Introduction to the Computation of Response Spectrum for Earthquake Loading

Robert M. Ebeling
U.S. Army Corps of Engineers
Technical Report ITL-92-4
June 1992

This technical report presents an introduction to the computation of a linear response spectrum for earthquake loading and defines the terms associated with response spectra. A response spectrum is a graphical relationship of maximum values of acceleration, velocity, and/or displacement response of an infinite series of elastic single degree of freedom (SDOF) systems subjected to time dependent dynamic excitation.

This report reviews the formulation and solution of the equation of motion for a damped linear SDOF system subjected to time dependent dynamic excitation. Due to the irregular nature of the acceleration time histories that have been recorded during earthquakes, numerical methods are used to compute the response of SDOF systems during the course of developing response spectra. The fundamentals of the solution of the equation of motion for SDOF systems are also described.

An Introduction to Wave Propagation in Pavements and Soils--Theory and Practice

R. Scott Ganin, P.E.
Alaska Dept. of Transportation & Public Facilities
AK-RD-91-02
February 1991

This paper introduces the physics and analysis of wave propagation in pavement and soils. The study of wave propagation in soils can yield useful results to engineers concerned with the resilient characteristics of a particular site, dynamic soil-structure interaction (e.g., pavements or soils), and earthquake analysis. Types of waves considered here are those resulting from forced impulses and ground penetrating radar. Background of the development in measuring waves in soils beginning in the late 1930's to the present is given. Practical and useful applications are presented along with equipment necessary to obtain results. Use of wave measuring equipment may expedite soil exploration in the future.

The Mechanism of Liquifaction in Layered Soils

Gregg L. Fiegel and Bruce L. Kutter
Naval Civil Engineering Laboratory CR 92.009
August 1992

Results from six centrifuge model tests are presented. Four of the model tests involve layered soil deposits subject to base shaking; two model tests involve uniform soil deposits of sand subject to base shaking. The layered soil models consisted of a saturated liquefiable fine sand overlain by a layer of relatively impermeable silica flour (silt). Pore water pressures, accelerations, and settlements were measured during all six tests. Results from the model tests involving layered soils suggest that during liquefaction, a water interlayer or very loose zone of soil develops between the sand and the silt due to the difference in permeabilities. Soil volcanos or boils were seen on the surface for all four of these layered model tests. The locations of these boils, in each test, were found concentrated in the weakest zones of the over-lying silt layer; cracking of the weak silt zones provided a release or a vent for the excess pore water pressure generated as a result of particle rearrangement in the liquefiable fine sand.

Models for Prediction of Surface Vibrations from Pile Driving Records

Brent R. Robinson
North Carolina State University
August 2006

This study compares high strain dynamic testing measurements taken near the top of a driven pile to peak particle velocities on the ground surface and sound levels detected in the air some distance from the pile during driving. Based on a sample of installation records from 16 piles driven at the Marquette Interchange Project in Milwaukee, Wisconsin, a series of peak particle velocity plots versus distance, energy and scaled distance were created using traditional horizontal distance and rated hammer energy. These plots were modified using the seismic distance, the diesel hammer potential energy from the calculated stroke, and the energy transferred to the pile top. Incorporating these measurements tended to reduce some of the scatter in the data. More importantly, it was also discovered that components of peak particle velocity in the ground can be well correlated to the total pile resistance measured by dynamic testing. A plot of total resistance versus depth often independently yields the same shape curve as a plot of at least one component of peak particle velocity versus depth. A simple mathematical attenuation model is proposed as an initial step toward utilizing this relationship to predict at least one component of ground motions. Measured peak overpressure (noise) in the air correlated less directly to the quantities measured on the pile, but a conservative and simple mathematical model can still be proposed based on the dynamic testing-measured velocity near the pile top and idealized sound generation and attenuation theories.

Site Characterization Philosophy and Liquefaction Evaluation of Aged Sands

Michael R. Lewis, Ignacio Arango, PhD and Michael D. McHood
Bechtel Corporation
2009

This paper describes site characterization using the cone penetration test (CPT) and recognition of aging as a factor affecting soil properties. Pioneered by Dr. John H. Schmertmann, P.E. (Professor Emeritus, Department of Civil and Coastal Engineering, University of Florida), these geotechnical engineering methods are practiced by Bechtel in general and at the Savannah River Site (SRS) in South Carolina in particular. The paper introduces a general subsurface exploration approach developed by the authors. This approach consists of “phasing” the investigation, employing the observational method principles suggested by R.B. Peck and others.

The authors found that borehole spacing and exploration cost recommendations proposed by G.F. Sowers are reasonable for developing an investigation program, recognizing that the final program will evolve through continuous review. The subsurface soils at the SRS are of Eocene and Miocene age. Because the age of these deposits has a marked effect on their cyclic resistance, a field investigation and laboratory testing program was devised to measure and account for this effect. This paper addresses recommendations regarding the liquefaction assessment of soils in the context of reassessing the SRS soils. The paper shows that not only does aging play a major role in cyclic resistance, but it should also be accounted for in liquefaction potential assessments for soils older than Holocene age.

a vulcanhammer.net special

Soil Motions Under Vibrating Foundations

John V. Perry (1924-2009) taught Mechanical Engineering at Texas A&M (with some breaks) from 1948 until 1995.

On a lighter note, his department head, C.M. Simmang (who signed off on the dissertation,) was commenting to his class on a visit by the late President Gerald Ford to San Antonio in 1976. Shaking his head in disbelief, he said, "At least I had enough sense to shuck the tamale before I ate it."

John Vivian Perry, Jr.
Texas A&M University
August 1963

This research was undertaken to determine the amount and extent of soil motions under vibrating foundations. The test soil was standard 20-30 Ottawa sand, ASTM C-190, that was contained in a one-meter cubical box. A force generator was mounted above the soil and applied dynamic loads to a circular footing. These were harmonic forces and were applied at frequencies between five and fifty cycles per second.

Three hundred and sixty-seven test runs were recorded on an electromagnetic oscillograph from signals generated by an acceIerometer buried in the soil. This acceIerometer was located at various depths beneath the center of a footing and, at other times, it was located beneath and offcenter. Other variables were the footings which had different diameters and masses.

Three empirical equations were developed from the test results using dimensional analysis. These equations were for maximum values of acceleration, velocity and displacement, respect ively.

a vulcanhammer.net special

Specifications for Control of Vibrations During Blasting and Pile Driving

Pierre Santoni
Northwestern University
December 1993

Controlling environmental effects of civil engineering operations has always been of concern to all parties involved in the construction process. Since control is exercised through the responsibilities outlined in contract specifications, these details are important. This work specifically addresses specifications that incorporate recent developments in the control of external construction vibration effects. These technical vibration specifications are intended to establish controls for the protection of nearby structures from ground vibrations, permanent ground deformation, emission of projectiles, and low frequency air overpressures. Annoyance of neighbors from noise and vibration intrusion also must be taken into account.

An attempt is made in this thesis to present suitable specifications for all types of blasting encountered today in civil engineering projects: production rounds, controlled, close-in and demolition blasting, as well as blast densification of sands. Special chapters deal with vibrations and soil displacement caused by pile driving, and with air overpressures created by both blasting and piling engineering.

The following conclusions are advanced, among others, concerning the geotechnical, the procedural, and the management aspects of vibration control specifications. It is necessary to take vibration considerations into account in the design of the project. This can be accomplished by making preconstruction surveys, by incorporating frequency considerations, and by setting realistic particle velocity limits. The specification should ask the contractor to meet given requirements, but should leave the choice of the method to his ingenuity. Specialists of the operations carried out on the site should be hired by the contractor, and test programs should always be performed before the start of full scale activities. Monitoring of vibration effects, such as peak particle velocity and air overpressures, requires special schemes, especially for pile driving, where two threshold values of particle velocity should be introduced. The engineer should not be considered only as the control authority, but also as a skilled person whose advise on specific problems can be valuable.

Technical Review and Comments:
2008 EERI Monograph "Soil Liquefaction During Earthquakes" (by I.M. Idriss and R.W. Boulanger)

Raymond B. Seed
University of California at Berkeley
Geotechnical Report No. UCB/GT--2010/01
April 2010

From Dr. Seed's Introduction:

"The recently published monograph by Idriss and Boulanger (2008), issued by the Earthquake Engineering Research Institute as part of their ongoing monograph series, presents a number of potentially important correlations and recommendations for assessment of potential hazard associated with seismically induced soil liquefaction. It is important that these recommendations be reviewed, and I have been asked to undertake such a review by a number of individual engineers as well as by a number of agencies and engineering firms.

"The views presented herein are my own, and do not represent the institutional views of any particular agency or other organization(s).

"The materials and recommendations presented in the monograph proceed in several distinct sections, and this review will not address all of these in detail. Chapters 1 and 2 of the monograph present an introduction to the general principles and phenomena associated with soil liquefaction, based largely on a good sampling of the works of others, and I will not address these chapters except to note that they are well written and provide a very useful introduction to the subject. Sections 4.3 through 4.6 similarly introduce a number of topics and issues associated with beginning to predict the consequences of soil liquefaction, but without attempting to resolve these into firm, quantitative recommendations for application to practice. This, too, is a generally useful discussion and it will not be reviewed in detail.

"Finally, Chapter 5 presents a few thoughts regarding mitigation of soil liquefaction hazard. This is a short treatment, and I will not provide a review of that chapter either. The remaining sections of the monograph present five potentially important sets of recommendations, and these will be reviewed in detail herein..."

a vulcanhammer.net special

Vertical Motion of Rigid Footings

This work is a classic for soil dynamics in general and the response of soil to the vibration of foundations in particular. Lysmer's simplification of the response equation was a major step forward in the rational analysis of this phenomenon.

Lysmer's Analogue--which reduced the soil response of a rigid circular foundation to a single degree of freedom spring-dashpot system--also has found application in pile toe response to pile driving, as was discussed in Closed Form Solution of the Wave Equation for Piles.

John Lysmer was for many years a Professor of Civil Engineering at the University of California at Berkeley. He passed away in 1999.

John Lysmer
U.S. Army Corps of Engineers Contract Report 3-115
University of Michigan
June 1965

This investigation includes a theoretical solution for a rigid footing, resting on an elastic half-space, which is subjected to steady-state vertical oscillation. It is shown how this steady-state solution can be used to describe the response of the footing to a transient pulse-type vertical loading.

After establishing the theoretical solution, and evaluating the approximations required for its development, it is further demonstrated that the theory permits evaluation of quantities which may represent spring constants and damping factors for use in the usual theory for vertical motion of a damped-one-degree-of freedom system. The agreement between the simple theory and elastic half-space theory is well within the limit required for engineering solutions.

The results of the study provide information from which the elastic dynamic response of rigid footings subjected to transient vertical loads may be evaluated. By taking advantage of such standard procedures as the phase-plane method, the dynamic response of footings may still be estimated even if the stresses in the soil extend into the inelastic range. A detailed discussion of the application of this method to inelastic settlements of vertically loaded footings will be presented in a subsequent report.

Finally, the theoretical developments included in this report for vertical oscillations may serve as a guide to develop similar theoretical evaluations of the dynamic response of rigid footings in other uncoupled modes of oscillation.