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Piedmont residual soils (PRS) comprise much of Virginia, Georgia, and the Carolinas. Thus, a better understanding of their stiffness properties is of paramount importance. The hallmarks of the soils within the Piedmont region are their low Standard Penetration Test (SPT) blow counts, saprolitic and its silty nature. To understand the stiffness properties of PRS, geotechnical exploration and in situ testing were conducted using SPT and Flat Dilatometer (DMT) testing. The results of the geotechnical explorations and in situ testing were studied and used to predict the settlement of the PRS. The results of the predicted settlement calculations were verified with the post-construction monitoring data and the recommendation of a method to predict the settlement of Piedmont soils was provided.

The design of shallow foundations is becoming an attractive choice for supporting highway bridge structures. The analysis is considered as a semi-empirical methodology that is based on linear and nonlinear models of behavior for settlement prediction. In this paper, the performance prediction methods for spread footing foundations are verified by using compiled field data based on vertical settlements measured on 23 sites of footings for 12 highway bridges selected in Ohio and Northeast of the United States. Six settlement prediction methods are selected for calculation immediate settlement of spread footings on cohesionless soils for each site and compared with measured values of settlement. The settlements of footings in sandy soils are often estimated based on the results of in-situ tests. In particular, the standard penetration test (SPT) is considered in this study for all six prediction methods. Statistical parameters corresponding to each of the six settlement prediction methods are evaluated and summarized. CE Database subject headings: Shallow foundations; Foundation settlement, Cohesionless soils, Standard penetration test, Prediction methods, Statistical parameters.

There have been several statistical methods developed to evaluate the probability of seismically induced soil liquefaction. Among these methods, the logistic regression has been the most widely used method to model the probability of liquefaction using the Standard Penetration Test (SPT) and Cone Penetration Test (CPT) based case histories. However, the predicted probabilities using logistic regression can be different based on the uncertainties related to distribution of explanatory variables, significance of coefficient of explanatory variables, and distribution of liquefaction to non-liquefaction case histories. In this paper, a possible approach has been developed to select the logistic regression model that best addresses these uncertainties for SPT and CPT based case histories using various statistical tests. This approach is developed for the most updated CPT based case histories from Ku et al. (2012), and SPT based case histories from Idriss et al. (2010). Further, the logistic regression model is compared with the existing probabilistic models for CPT and SPT based case histories. This study shows that without considering the aforementioned uncertainties, the probability values can be significantly different and can give false sense of risk of liquefaction for a particular site of interest.

For monopile, where single pile carries all the lateral forces and moments, predicting top displacement and slope with reasonable accuracy becomes important in design practice. In this study, linear Winkler's (1867) model is created in which monopile is modeled using beam-column element with roller support at its bottom and surrounding soil is represented by linear springs. Matlock's (1970) recommendation has been used to calculate soil spring constant from its Young's modulus estimated through shear modulus. Deflection of simulated pile has been compared for various recommendations of Gmax estimation through SPT (standard penetration test) values. Predicted deflection showed large variation questioning its accuracy. Since average strain level of the soil during loading is actually unknown, one can assume any strain level to find a desired value of G to match the same deflection for any of those Gmax correlations. Similar analysis showed a large variation in the strain level expected in different correlations. This creates discomfort in taking design decisions and requires finding a way to approximately calculate the applicable average strain level corresponding to the induced deformations at various depths of monopile.

The prediction of pile-bearing capacity to include installation effects is a very complex problem, especially for jack-in piles. This paper describes a series of full scale pile load tests that shed light on the effects of jack-in force on the ultimate bearing capacity of jack-in piles. Three spun piles were installed in similar soil conditions under different jack-in forces. The extensive in-situ investigations, including standard penetration test (SPT), pressuremeter test (PMT), and piezocone penetration test (CPTU), were conducted in the experimental site to get better understanding of the soil condition around the test piles. The results of the tests show that the different jack-in forces did not affect the shaft friction significantly and that the difference in behaviors between test piles is caused by the difference in the toe stiffness response. The data show that the larger the jack-in force, the larger the stiffening effect, which is due mainly to the increase in volumetric compression of the bulb of soil below the toe of the piles.

The paper presents an application of 2-D time-domain waveform tomography for detection of embedded voids/anomalies. The measured seismic surface wave fields were inverted using a full waveform inversion (FWI) technique, based on a finite-difference solution of 2-D elastic wave equations and Gauss-Newton inversion method. The key advantage of this approach is the ability to generate all possible wave propagation modes of seismic wavefields (body waves and Rayleigh waves) that are then compared with measured data to infer complex subsurface properties. Both the pressure wave (P-wave) and shear wave (S-wave) velocities are inverted independently and simultaneously for possible indication of soil types. The inversion results of real data set show that the waveform analysis was able to delineate a complex profile with an embedded void and highly variable bedrock both laterally and vertically. Independent invasive test (standard penetration test, SPT) was also conducted to verify the seismic test results. INTRODUCTION Sinkhole detection in a site usually begins with non-destructive testing (NDT) assessment study, as NDT data can provide general subsurface conditions over large volume of materials. At suspicious locations (anomalies), more involved invasive methods such as Cone Penetration Test (CPT) or Standard Penetration Test (SPT) are then conducted to obtain more detailed information if needed. Since the 1980s, various approaches have been developed and employed to characterize sinkholes, ranging from gravity, resistivity, Ground Penetrating Radar (GPR) and traditional seismic wave methods (FHWA, Technical Manual 2003). These existing methods 2382 Geo-Congress 2014 Technical Papers, GSP 234 © ASCE 2014

A series of Becker penetration tests (BPTs) was recently conducted in a gravelly alluvial soil at a dam site in California to assess its liquefaction potential. The BPT program included both measurements of bounce chamber pressure, which is used in the Harder approach, and a pile driving analyzer (PDA), which is used in the Sy approach. The resulting equivalent standard penetration test (SPT) blow counts from the Harder and Sy approaches were computed and found to differ significantly. As a result of the appreciable difference in equivalent SPT blow counts, each approach was critically reviewed, and a summary as it pertains to this site is presented. Results from additional site investigation using sonic boring and shear wave velocity measurements are also presented here, as they provide additional insight into interpreting the BPT results. This paper provides a useful case history of a well investigated site and compares the strengths and weaknesses of the current BPT approaches for calculating equivalent SPT blow counts.

The compression modulus is a key parameter for evaluating compression behavior of soil layer and for predicting foundation settlement. Highpressure confined compression test and the standard penetration test were performed to investigate the compression characteristics of sandy soil layers beneath pile toe, and to obtain the relationship of compression modulus with depth and overburden pressure. The experimental results indicated that the compression modulus of sandy soil increased with pressure, but its increasing rate gradually reduced. The compression modulus almost linearly increased with embedded depth. The ratio of compression modulus under the pressure ranging from 100kPa to 200kPa to that under the pressure in the range of overburden pressure to the additional stress plus overburden pressure (Es/Es0.1-0.2) ranged from 2.1 to 4.2. The empirical formula of the Es/Es0.1 -0.2 ratio with overburden pressure was established to give a reference to predict compression modulus of sandy soil under actual pressure, as its overburden pressure was known. At last, the basic principles of how to determinate the value of compression modulus were proposed for design of pile foundation.

Liquefaction of saturated soil has often been one of the causes of earthquake damage to structures resulting in loss of life and property. The additional safety in the design of superstructure is not of any help in the event of liquefaction of foundation soil during an earthquake. It is therefore very necessary that possibility of liquefaction is examined before hand and necessary remedial measures are adopted against damages due to liquefaction of foundation soil. Complex behaviour of soil liquefaction phenomena makes prediction of liquefaction costly and time consuming task. Fortunately, liquefaction occurs only under certain conditions. To take advantage of this fact various criterions are suggested to screen liquefaction potential in different code of practices. These criterions proved very useful and handy for practicing civil engineers and eliminate specialized evaluation of liquefaction potential. Most commonly used criteria for evaluation of liquefaction resistance is based on the standard penetration test (SPT). Here an attempt is made to examine such provisions in Indian and US code of practices. IS 1893 part-1 and The Building Code of The City of New York 2004 suggests liquefaction evaluation is not required if SPT N value is more than 15 (near to ground) to 25 (depth of 15 m from ground). Detailed liquefaction analysis is carried out as per NCEER, 1997 (Youd et al., 2001), most common method proposed in most of the code. Analysis reveals factor of safety against liquefaction much lower than 1 (e.g. 0.32 only for N value of 16 at 2 m depth for maximum ground acceleration of 0.36 g). Which suggest these provision need to be evaluated. Further comparison is made with Eurocode8 and FEMA guidelines in which suggested SPT N value greater than 30 for no liquefaction for clean sand. As these provisions are only screening criterion therefore need to be conservative. If based on these quick and simple provision possibility of liquefaction is predicted, detailed analysis may be warranted.

A building pad was certified for an allowable bearing pressure of 191.5 kilopascal (KPa). Subsequent to the pad certification the site contractor had repeatedly driven across the building pad with heavy equipment. Due to this, the surficial soils in the building pad yielded in some of the areas. Subsequently, standard penetration test (SPT) test and laboratory unconfined compressive strength (UCS) tests were performed by others on the prepared pad and it was concluded that the bearing pressure should be significantly lowered to 71.8 KPa from 191.5 KPa. The UCS test used to estimate the shear strength of soils is most common test in engineering practice. However, engineers often overlook one of the important soil parameters, the soil suction, which considerably affects the soil behavior. The increase in soil suction considerably increases the soil shear strength. A simplistic approach was adopted to measure the shear strength of partially saturated soils. A series of unconsolidated undrained (UU) tests were performed at different matric suction and by maintaining the same lateral confining pressure. Since the shear strength measured in the UU test reflects in-situ matric suction of the soil, an increase in matric suction significantly increased the undrained shear strength of a partially saturated soil. This in turn increased the bearing capacity of the soil and thereby the factor of safety. Based on the results from the test, it was concluded that the subsurface soils present at this site had adequate strength to support an allowable bearing pressure of 191.5 KPa. Further, it was also proved that the cause of pad rutting was not due to lower bearing capacity, but it was due to the trucks exerting 40% more load than the allowable bearing pressure of 191.5 KPa.

Compactness of the soil fill below the footing is an important criterion as it probes the chance of settlement of the structure. It is very difficult to estimate the degree of compactness of soil layer beneath the finished floor or footing using any conventional geotechnical testing as these testings are time consuming and random in nature. In this study an attempt has been made to investigate the homogeneity of the compaction quality of new soil fill below the finished floor slab using ground penetrating radar (GPR). This forensic investigation has been carried out to probe height and quality of compaction of soil layers below newly constructed industrial floor slab and machine foundation tilted and cracked site. The GPR survey has been carried out at identified three locations using ground coupled 500 MHz antennas capable of penetrating minimum depth of 6 m. Analysis of GPR radargram shows that electromagnetic wave characters and amplitude of wave traces are not uniform. Change in the wave characters are indicating heterogeneity in quality of compaction layers. Change in the wave amplitude in the same layer shows decrease in water content, which in turn reflects loose compaction. GPR results are compared with drilled borehole and measured soil strength in terms of standard penetration test (SPT) N values at distressed location.

The improved depth of dry jet mixing (DJM) in China is limited to being less than 15m due to the limitations of DJM machine; and the strength of cement-mixing column reduces with depth. An innovation method to enhance column quality in deeper layers is presented in this study. A remarkable combined method of DJM with prefabricated vertical drains (PVD), termed DJM-PVD combined method, was innovated and successfully practiced in two highway projects on very soft clay in Jiangsu Province, China. The field experiment results indicate that DJM-PVD combined method makes the installation of DJM columns easier and the cement powder can be spouted out better than isthe case without PVD, especially in deeper layers and enabling the mixing of column more homogeneously and, consequently, effectively increasing the strength of DJM column. The procedures used for DJM-PVD combined method, the instrumentation and the field monitoring data about columns strength, such as standard penetration test (SPT) blow counts and the unconfined compression strength (UCS) of DJM columns core samples, are described. Potential reasons for enhancement effect of PVD on DJM column quality are discussed.

Soft ground is often improved to increase strength and stiffness by methods such as jet grouting and stone column which result in heterogeneous ground with improved columns. Experimental methods (Standard Penetration Test, sampling and laboratory testing, etc.) used to assess such ground improvement are subjected to several limitations such as small sampling volume, time-consuming, and cost ineffectiveness. It’s difficult to assess the average property of the improved ground and the actual replacement ratio of ground improvement. The use of seismic surface wave method (i.e. multi-station analysis of surface wave, MASW) for such a purpose seems to be a good candidate. But the surface wave method is essentially a 1-D method assuming horizontally-layered medium. What MASW measures in the highly heterogeneous improved ground remains to be investigated. This study evaluated the feasibility of MASW in the heterogeneous ground with improved columns and investigated the homogenization of shear wave velocity measured by MASW. The lateral sampling space of the surface wave testing was also investigated by field testings of different survey line locations relative to the improved columns. The engineering information that can be extracted from the improvement rate of shear wave velocity obtained by surface wave testing is discussed.

The paper presents recommendations for conducting geotechnical site characterizations to obtain design parameters for settlement and stability analyses. It focuses on relatively uniform, saturated cohesive soil deposits with near zero Standard Penetration Test blow counts and soft ground conditions, which means that construction will load the foundation soil beyond its preconsolidation stress. The site characterization program should select an appropriate combination of in situ tests for soil profiling (identify soil types and their relative state) and laboratory tests on undisturbed samples for strength-deformation-flow properties. Although the tools, procedures, and interpretation methods needed to conduct a reliable site characterization program are well developed, general practice often ignores this knowledge. Thus a prime objective of the paper is to provide recommendations for moving practice closer to the state of the art. Components of site characterization covered include site stratigraphy, drilling and undisturbed sampling, in situ testing, and laboratory consolidation and strength testing. Key recommendations include: fixed piston sampling using drilling mud and tubes with an appropriate geometry, piezocone testing for determination of site stratigraphy, radiography of sample tubes, debonding of samples from tubes, evaluation of sample quality, CRS testing to measure consolidation behavior, and anisotropic or K0 consolidated strength tests to measure undrained shear strength behavior.

A geotechnical investigation of a site for two large buried water storage reservoirs was recently conducted. The geotechnical investigation used multiple insitu field methods to characterize the recent alluvial and fluvial deposits overlying bedrock that underlie the reservoir site. The recent deposits had a gravel, cobble and boulder content which made characterization of these deposits by the usual in-situ methods, such as the standard penetration test (SPT), more difficult. Because of the coarser grained materials, Becker Penetration Tests (BPTs) were performed to provide continuous penetration resistance at several locations throughout the large site. To provide additional information, Spectral Analysis of Surface Waves (SASW) testing was performed to characterize the thicknesses and shear wave velocity (Vs) profiles of the alluvial and fluvial deposits and the underlying bedrock. The SASW results were compared with the results of shear wave velocity profiling using the suspension logging technique performed in several rotary wash borings at the site. The SASW shear wave velocity profiles, in combination with the other investigation methods, were useful in determining the nature of the subsurface materials and refinement of the soil and bedrock profiles for liquefaction and soil-structure interaction analyses required in the design of the reservoir structures.

This paper investigated the influence of local geotechnical and geological soil conditions on the intensity of ground shaking of Dubai-Sharjah metropolitan area (DSMA). Acceleration-time histories of Dubai and Sharjah were chosen according to spectral shape and similarity in magnitude and distance to a target response spectrum that were obtained from the results of Seismic Hazard Analysis (SHA). Subsurface geotechnical data of 72 different sites, located in the area under consideration, were used in this study. The effect of local site conditions on ground response during earthquake has been evaluated by performing equivalent linear analysis. Dynamic properties of selected soil profiles were evaluated using empirical relations between Standard Penetration Test (STP) N-values and shear wave velocity (Vs). Modulus degradation and damping curves for sand and rock were also employed in the analysis. Results indicated that surficial deposits in the area amplified earthquake ground motion. The peak amplification was observed over relatively narrow frequency range of 1.5-5 Hz (0.2-0.8s period) that was found to represent the predominant frequency range of the site classes under consideration. Amplification factors at PGA and at both short and long periods (0.2s and 1.0s), which are site class dependent, were compared to the current code of practice.

As the tallest building in Cincinnati, the 45 story Great American Tower at Queen City Square is not only changing the downtown skyline, but is also contributing to the advancement of the state-of-the-art use of auger cast-in-place (ACIP) piles as settlement reducers. Predicted settlements of a traditional mat foundation were excessive, and the costs and construction time associated with traditional ACIP piles extending to bedrock were not preferred. A mat supported on a limited number of ACIP piles, with the piles primarily acting as settlement reducers, was evaluated as the preferred foundation type. Traditional standard penetration test boring data was initially used to develop a numerical analysis of the soil-structure interaction using FLAC 3D software. The model was further modified with cone penetration and pressuremeter testing, along with actual load test results on several ACIP pile elements of varying lengths, but all tipping above bedrock. Through numerous project team discussions, and detailed numerical modeling analyses, ACIP piles were recommended for reducing mat foundation settlement. The process used advanced geotechnical analysis and design to mesh traditional mat and ACIP pile foundations into a unique soil-structure interaction based foundation system.

Several correlations between the standard penetration test (SPT) N-values and internal friction angle (φ') have been developed for granular soils. Some correlations have also been developed for un-drained shear strength of saturated clays. However, in many instances soils do not behave as either saturated clay or sand. Sometimes it is important to find the contribution of φ' in clays with higher silt and sand content; and cohesion in sands that has sufficient clay and silt content. It is incorrect to classify these soils as cohesive soils with no friction angle, or as granular soils with no cohesion, and is thus the focus of this research. This paper describes a research effort to develop practical relationships between φ', effective cohesion (c') and SPT N-values for granular-cohesive soils. Considering the SPT analogous to a miniature pipe pile, an energy-balance approach was taken to derive a relationship between φ', c', N-values and effective overburden pressure (σ'). A second relationship was derived between φ', c', σ' and the liquidity index (LI) of low-sensitivity granular-cohesive soils. The two relationships were then graphically solved to formulate direct correlations between field N-values and c' and φ'.

Historical seismicity data and recent seismic activities in and around Bangladesh indicate that Bangladesh is at high seismic risk. The capital city Dhaka is situated in the seismic Zone 2, which has a basic seismic coefficient of 0.15g. Over the past 40 years, Dhaka city has experienced a rapid growth of urban population. This high population increase demands rapid expansion of the city. Unfortunately, most parts of the original ground have already been occupied. As a result, both government and private agencies are reclaiming different new areas. In most cases, the practice for developing such areas is just to fill lowlands (3~12 m) by dredged material, which is almost silty sand. This is inviting great liquefaction susceptibility for such reclaimed areas. The field SPT N-value of the filling depth varies from 1 to 13. Mean particle diameter and fines content of the fill materials vary from 0.10~0.32 mm and 6~48%, respectively. Liquefaction potential of selected reclaimed areas of the city has been estimated based on standard penetration test and shear wave velocity. It is found that some parts of the reclaimed sites are susceptible to liquefaction up to the filling depth.

Drilled shaft capacity computations are routinely performed by geotechnical professionals using the Alpha and Beta methods outlined in the Federal Highway Administration (FHWA) Publication FHWA-IF-99-025. For cohesionless intermediate geomaterials, the analysis relies heavily upon the Standard Penetration Test sampler blow counts obtained from exploratory borings. In the presence of alluvial gravel, cobble and boulder deposits, such evaluation cannot be reliably performed. This paper presents information obtained from Osterberg Cell load testing of 2.5-meter (98-inch) diameter shafts advanced using the casing oscillator method at the Cypress Avenue Bridge over the Sacramento River in Redding, California. The relationships between side shear transfer, end bearing, and settlement in cobble and boulder rich deposits with various matrix materials and degrees of weathering are demonstrated. The effects of particle dilation in the development of shaft side resistance and zones of higher stress concentration are also discussed. The results of instrumented pile load testing are compared with the results of drilled shaft capacity estimates made using the FHWA methods in an effort to better correlate field performance with analytical methods.

With the increasing use of auger pressure grouted (APG) piles in new construction, it is important that proper design parameters be incorporated when evaluating pile capacity and performance using reliability-based design methods. This paper focuses upon developing t-z model parameters and their variability from analysis of static axial compression tests on APG piles. Data from ten static pile load tests conducted on APG piles from construction sites and literature were obtained. Load-settlement curve fittings between the measured data and the theoretical data were conducted using the t-z method to back-calculate a set of soil-pile interfacial and tip parameters. The t-z model parameters are compared to standard field investigation data, including standard penetration test (SPT), cone penetration test (CPT) and effective stress of the ground to develop correlations suitable for the design of APG piles. Subsequently, the t-z model for APG pile design was developed and the model efficiency was evaluated by comparing the predicted and measured load-settlement and load transfer curves.

The Terzaghi and Peck (1948) method was the first for predicting the settlement of footings on sand using standard penetration test blow counts (N values). Over the following 26 years, various modifications to this basic method were suggested. Herein, an extensive database of 426 settlement case histories is used to assess the model factors for this family of methods. The uncertainty of the model factors is characterized using the coefficient of variation. Considering the model factor as a random variable, the common log-normality assumption is investigated critically. The impact of model uncertainty on the reliability of settlement estimations is discussed, and criteria are given to assess their accuracy and conservatism. For settlement prediction, the uncertainty from the model factor is most influential. The results indicate a low accuracy for all of the methods considered.

American Association of State Highway and Transportation Officials (AASHTO) allows individual states to use regionally calibrated resistance factors based on the local soil conditions to improve the cost effectiveness of pile foundations as long as the development of these factors comply with the Load and Resistance Factor Design (LRFD) concept. This paper presents preliminary resistance factors developed for the Wave Equation Analysis Program (WEAP) using the PIle LOad Test database of the Iowa Department of Transportation (PILOT-IA). Using the pile penetration rate (blows/m) at the end of driving as the main variable, the LRFD calibrations for WEAP were conducted using 32 sites comprising the following four soil categories: clay (8 sites), mixed soil (11 sites), sand (13 sites), and all soil types (32 sites). Three different procedures, namely the Iowa DOT steel pile design chart, the DRIVEN program, and the GRLWEAP TM SPT N-value based method (SA), were used to estimate the soil driving resistance. When compared to the AASHTO (2007) recommended LRFD resistance factors, the developed resistance factors for clay increased by 125%, while the resistance factors for the mixed, sand and all soil types improved by 50%. Among the procedures used for estimating the soil driving resistance, the resistance factor based on the SA method yielded the highest efficiency factor for mixed, sand and all soil types, while the Iowa DOT design chart led to the best efficiency factors for clay soil. In addition to using 32 data sets from PILOT-IA, data from three recently completed load tests were used to examine the effect of the pile setup on the resistance factors. Pile driving records and restrike data were used to predict the pile capacity as a function of time and establish a modified empirical pile setup equation incorporating a soil property using the Standard Penetration Test (SPT) N-value. In addition to incorporating this information, the paper demonstrates the benefits of incorporating the soil setup in resistance factor calculations.

Silt has engineering defects and its California bearing ratio (CBR) value is low when it is used as roadbed filling. In order to analyze the influence of different factors on the CBR value of the silt roadbed, the CBR value is measured by changing silt particle content, initial water content, adding different salt and salt content, and changing overload pressure. The influence characteristics of different factors were also analyzed. The specimens were fabricated by heavy compaction criterion and soaked in water for four days. The standard penetration test was used to measure CBR value. The test results show that the CBR value of silt filling becomes larger as the silt particle content is reduced. The initial moisture content has remarkable influence on the CBR value, and the CBR value reaches the maximum with the optimum water content. The different salts and salt content have different effects on the CBR value, and the CBR value reduces to a great extent as the salt content increases. The overload pressure also has great influence on the CBR value, which becomes larger as the overload pressure increases. The research shows that the useful methods to improve the bearing capacity of silt roadbed include adding sand, controlling the compacted moisture content, reducing the salt content and preloading.

A new s-wave probe, called "MudFork," has been recently developed and is used in accurate measurements of shear wave velocities of soft soils. The probe is composed of two bender elements mounted on a "fork" having two blades, one element perturbing ground and the other one monitoring seismic waves, and can be penetrated using SPT (standard penetration test) rods pushed with a routine boring machine. To expand its use to estimate undrained shear strength and density, an attempt to correlate shear wave velocity to those properties was made at normally consolidated silt near Incheon, Korea. A simple linear relationship between shear strength and shear wave velocity was obtained, and a tentative relationship between density and shear wave velocity was also defined.

This study examines representative analytical models to evaluate the tip capacity of drilled shaft foundations under axial compression loading. To ensure a reliable analysis, a wide variety of compression load test data were used for this purpose. Thereafter, these data were divided into drained and undrained databases based on the soil conditions along the shaft tip. For the evaluation of the bearing capacity theory, the predicted and measured results for undrained soils are reasonably consistent. However, the results showed that the predicted model greatly overestimates the tip capacity for drained soils. On the average, the measured capacity of the drained soils is about 10-20% of the predicted theory model under tolerable settlement. The possible influence factors are discussed and a simple suggested correction factor for shaft length is proposed. For the empirical method, the relationships between tip capacity and standard penetration test are directly developed from the measured results.

Surface wave methods provide an in situ shear wave velocity profile for a soil system. The most difficult component of the various methods is typically the inversion process. The study presented herein demonstrates a new protocol to guide or constrain the inversion process to provide a quality, realistic shear wave velocity profile. In this study, a database of experimental dispersion data was created, from which five general trends of dispersion data were chosen. The simplified models were used to demonstrate details of the new protocol. Based upon the analyses performed, the inversion protocol is shown to successfully invert a wide range of dispersion data. For the cases presented, the observed fit between experimental and predicted dispersion curves is excellent, and the shear wave velocity profile appears reasonable, believable, and in sufficient detail. Further, the trend in shear wave velocities determined via the protocol is quite consistent with material classification and standard penetration test results available. Using shear wave velocity uncertainty estimated via an error prediction procedure as a criterion, a conclusive stopping criterion for the inversion was noted: follow the protocol until no further layers as small as 0.3048 m (1 ft) can be added to the profile. INVERSION PROTOCOL ABSTRACT: Surface wave methods provide an in situ shear wave velocity profile for a soil system. The most difficult component of the various methods is typically the inversion process. The study presented herein demonstrates a new protocol to guide or constrain the inversion process to provide a quality, realistic shear wave velocity profile. In this study, a database of experimental dispersion data was created, from which five general trends of dispersion data were chosen. The simplified models were used to demonstrate details of the new protocol. Based upon the analyses performed, the inversion protocol is shown to successfully invert a wide range of dispersion data. For the cases presented, the observed fit between experimental and predicted dispersion curves is excellent, and the shear wave velocity profile appears reasonable, believable, and in sufficient detail. Further, the trend in shear wave velocities determined via the protocol is quite consistent with material classification and standard penetration test results available. Using shear wave velocity uncertainty estimated via an error prediction procedure as a criterion, a conclusive stopping criterion for the inversion was noted: follow the protocol until no further layers as small as 0.3048 m (1 ft) can be added to the profile.

Elastic theory is used to back-calculate the drained secant soil modulus from loads and settlements measured in full-scale load tests on footings in axial compression. The moduli are evaluated at L 1 (the end of the initial linear region) and at a settlement of 1% of the foundation width. These drained soil moduli are normalized by standard penetration test results at each site, and the normalized values are correlated effectively with the soil stress history, stress state, and stress level. The resulting correlations will be useful for footing design.

Despite its many perceived shortcomings, the Standard Penetration Test remains the most common site investigation tool used throughout the world. The results from the SPT are often used to estimate side resistance of piles. The SPT- Torque Test or SPT-T is a simple modification to the SPT in which the traditional SPT is complemented by a torque measurement after driving the split spoon to give a more direct measurement of side resistance between the soil and the spoon. SPT-T tests performed at a number of sites demonstrate that the results obtained from the SPT-T may be used to estimate pile side resistance much in the same way that the CPT "friction sleeve" is used. The results show a direct correlation between SPT N60-values and unit side resistance. This is consistent with observations reported in the literature relating N to side resistance of full scale piles. The results are used to provide some reasoning for the apparent correlations reported in the literature and suggest that the SPT-T can be a valuable test for making preliminary estimates of pile side resistance. ABSTRACT: Despite its many perceived shortcomings, the Standard Penetration Test remains the most common site investigation tool used throughout the world. The results from the SPT are often used to estimate side resistance of piles. The SPT- Torque Test or SPT-T is a simple modification to the SPT in which the traditional SPT is complemented by a torque measurement after driving the split spoon to give a more direct measurement of side resistance between the soil and the spoon. SPT-T tests performed at a number of sites demonstrate that the results obtained from the SPT-T may be used to estimate pile side resistance much in the same way that the CPT "friction sleeve" is used. The results show a direct correlation between SPT N60-values and unit side resistance. This is consistent with observations reported in the literature relating N to side resistance of full scale piles. The results are used to provide some reasoning for the apparent correlations reported in the literature and suggest that the SPT-T can be a valuable test for making preliminary estimates of pile side resistance.

Ocean Earth Technologies, Inc. (OET), a subsidiary of N.S. Nettles A Ocean EarthTechnologies, 2006; Ocean Earth Technologies, 2006). These surveys were followedby 45 Standard Penetration Test (SPT) borings and 60 ten foot long, four inch rockcore borings in order to ground-truth the geophysical data and obtain physicalsamples for laboratory analysis of engineering properties for design purposes.Additionally, 71 Cone Penetration Test (CPT) soundings were also performed on thebeach front unconsolidated sands.

On June 13, 2006, several large sinkholes developed within Scott Lake, Polk County, Florida. Due to potentiometric head differences between the lake and the underlying Floridan aquifer, one of the sinkholes drained the entire lake over a seven-day period. Slope failures affected the shoreline and damaged residential properties and other structures. The exposed lakebed revealed two large cover-subsidence sinkholes aligned along a northwest trend, along with multiple circular topographic features consistent with older, in-active (paleo) sinkhole features. Investigation of residential structures along the lakeshore found minor to significant settlement damage related to the slope failures and soil raveling. Standard Penetration Test (SPT) borings showed significant stratigraphic disruptions in the subsurface, suggesting the recent sinkhole activity was associated with reactivation of the pre-existing paleo-sinkhole feature(s). Remediation of damaged properties included compaction grouting to stabilize deeper raveled soils, in combination with foundation underpinning and shallow chemical grouting. The size of the sinkhole features and rapid draining of the lake require substantial cavernous permeability within the Floridan aquifer. Periodic reactivation of paleo-sinkhole features and development of new sinkholes are part of the cycle of formation of lake basins within the mantled karst upland areas in Central Florida. It also provides a mechanism for the transport of large amounts of fine organic sediments into the subsurface.

The subsurface exploration of a site is often the aspect of a project that gets overlooked during the design process. Many clients will get standard soil borings, but do not want to pay for a full laboratory analysis. Lack of data forces the designer to estimate important engineering properties of the soil. Very often the Standard Penetration Test (SPT) blow counts are used to estimate the shear strength properties of soil in foundation designs. Few correlations are widely used. However, no clear explanation is found to justify the selection most of these mathematical equations. This manuscript describes a new approach to estimate the shear strength parameters based on the SPT blow counts. In this method, the standard penetration test is treated analogous to driving a miniature pipe pile. The energy input to the soil is used to correlate the SPT blow count to the shear strength parameters of the soil at the depth of testing. Soil boring records from few different sites were analyzed and a statistical analysis revealed that the proposed method can provide a better estimation than the widely used existing correlations.

In this paper, characterization and geotechnical properties of Piedmont residual soils are presented for two research sites located at the Carolina slate and Charlotte belts of North Carolina. Similar to most other residual soils, the index and geotechnical properties of the Piedmont residual soils are highly variable. Site investigations were conducted at the test sites using standard penetration test (SPT) and borehole shear test (BST). Also, a series of laboratory tests were performed to obtain consolidated undrained (CU) triaxial strengths and index properties of the soils. By comparing the CU strength of the soils to the borehole shear data at known moisture contents, the strength properties attributable to degree of saturation or suction were estimated.

The Sowers dynamic cone penetrometer (DCP) has been used as a relatively low-cost near-surface soil investigation tool in the Southeastern United States for over 40 years. Typically, the Sowers DCP penetration resistance has been correlated to standard penetration test (SPT) N values for use in geotechnical analyses such as bearing capacity evaluation. Published correlations of DCP and SPT penetration resistances are limited to Piedmont residual soils in and around Atlanta, Georgia and soils in Idaho, Utah, and Wyoming. Correlations of Sowers DCP test results to piezocone penetration test (CPTu) and flat blade dilatometer test (DMT) measurements have not been examined. The following paper examines correlations between the Sowers DCP penetration resistance ( n ), corrected tip resistance (q t ) from piezocone penetration testing, and dilatometer modulus (E D ) from flat blade dilatometer testing in lower Atlantic Coastal Plain soils. Testing data were collected from eight sites in the Charleston, SC area. Correlations were conducted taking into account soil classification and groundwater location. Analysis of the data showed no clear correlations exist between these three test measurements with the exception of a linear relationship between n and q t for silty sands below the groundwater table, where a relationship of q t,ave (MPa)/n approx. 0.5 was observed regardless of classification method.

Different procedures for performing the standard penetration test (SPT) were employed during the site investigation at a fluvial sand site along the Ohio River. Comparison of the collected data shows that the SPT blow counts, i.e. N-values, were significantly affected by the test procedure used, due to the “flow-sand” phenomenon that occurred in the sandy soils below the groundwater table. The test procedure used can also have an effect on the laboratory test results obtained from the soil samples, such as grain size distribution. Based on experience at this site, reasonable SPT results can be achieved using either the mud rotary drilling method or the hollow stem auger method; however, if the hollow stem auger method is used, the insides of the augers need to be filled with bentonite mud during the test, and the mud should be added each time the augers are advanced.

The Menard pressuremeter test can be successfully performed at any depth, this pressuremeter (designated by PMT) has a greatest advantage for seabed and other underwater tests from floating platforms, since there is no need for a stiff linkage between the probe and the drilling platform. In-situ test of a bridge foundation ground, envolving underwater sedimentar soft clay and sand by using GA pressuremeter, is introduced. Based on the interpretation of drill borehole geologic data, a linear relationship between standard penetration test values (N 63.5 ) and bearing capacity of foundation based on pressuremeter test was assumed. The correlation between N 63.5 and bearing capacity of foundation derived from PMT are different because of the difference of soil properties. For hard soil foundation, the increasing degree of bearing capacity of foundation calculated from pressuremeter test with N 63.5 is small. And the increasing degree of bearing capacity of foundation calculated from pressuremeter test with N 63.5 is rather large for soft soil foundation. It can be well used for ascertaining the ground bearing capacity by SPT and partial pressuremeter test data and determining the position of supporting course.

Modern methods for designing drilled shafts, ACIP piles and similar foundations in soft rock require knowledge of the compressive strength and modulus of the rock. However, jointing at many sites prohibits the recovery of samples of sufficient length and integrity to test rock cores in either unconfined or triaxial compression. Since rational design procedures usually require values of compressive strength, surrogate methods must be employed to estimate the compressive strength of the rock. The surrogate methods considered here is the Texas cone penetrometer test (in which a 76-mm-diameter solid steel cone is driven into rock at the bottom of a borehole in much the same way as a split spoon is driven during the performance of a standard penetration test in cohesionless soil). An other issue during deep foundation construction is essential to locate the a rock stratum, especially when drilling with slurry, in which the bottom of the borehole cannot be observed and the cuttings may be so disturbed that overburden soil cuttings cannot be easily distinguished from cuttings in soft rock. Hence, a new static rock penetrometer was developed based on the concept of the pocket penetrometer, which has been used by field geotechnical boring loggers for many years. Soft rock formations typical of those for which such substitutions might be used are the upper Cretaceous formations of North central Texas, including the clay shale and limestone formations. The correlations between compressive strength and the Texas cone penetrometer test are formation-dependent, most likely through the degree of cementation present in the geomaterial. Also, the performance of the static penetrometer was verified in the field in boreholes that were drilled at the test sites in North central Texas. The readings at these sites, together with the values of q u measured using cores taken from the same elevation as the penetrometer test and Texas cone penetrometer resistance values at the same elevation in nearby boreholes. The readings were all made in open boreholes, not under slurry. Based on test results, a static rock penetrometer reading between score marks B and C (B-C) is indicative of soft, sound clay shale, and a reading of C or higher is indicative of sound limestone or sound, hard clay shale. Readings of B, A-B and A are indicative of overburden materials.

Soil proprieties are typically determined from a limited number of in situ or laboratory tests performed at a specific site. The results of these tests may be used to estimate soil properties of the whole site by means interpolation techniques such as linear, polynomial, statistical or machine learning methods. In this paper, a Standard Penetration Test (SPT) database from the port of Navegantes, south Brazil, is used for analysis. Geotechnical mapping of SPT blow counts is made using classical interpolation methods and the neural networks technique, and their performance compared.

The study presented herein documents procedures to assess uncertainty in shear wave velocity determined via SASW, and demonstrates use of these uncertainty estimates to guide the inversion process to provide a quality, realistic shear wave velocity profile. Based upon the analyses performed, the inversion protocol guided by uncertainty estimates is shown to successfully invert dispersion data. For the site example presented, the trend in shear wave velocities determined via the protocol is quite consistent with the material classification and standard penetration test results available for the site. It is shown that uncertainty in shear wave velocity is a function of the number of soil layers used in the inversion. As the number of layers increases, uncertainty in shear wave velocity also increases. The results also suggest that the layer resolution of SASW inversion on soil sites is approximately 0.3048 m (1 ft).

The resilient modulus is used in the characterization of base and subgrade soils and in the design of pavement structures. The resilient modulus of subgrade soils can be estimated by using expensive and time-consuming laboratory test results or from overestimated backcalculated values from nondestructive test results. These limitations imply that the need of a simple and inexpensive insitu geotechnical test method to estimate the resilient modulus of subgrade soils. The dynamic cone penetration test is considered as a simple, rapid, and economical insitu test in geotechnical applications. However, the application of the dynamic cone penetration test in evaluating the resilient modulus of pavement subgrade soils is not well known. The objective of this paper is to develop correlations to predict the resilient m odulus of subgrade cohesive soils from the dynamic cone penetration test parameters, soil type, moisture content, and dry unit weight. Twelve laboratory -compacted large soil samples of two cohesive soil types and six test locations in two existing pavement s were used to perform the dynamic cone penetration tests. Laboratory resilient modulus and soil property tests were also performed. The preliminary estimation models were developed for the prediction of the resilient modulus of subgrade soils from the dynamic cone penetration test parameters, moisture content, dry unit weight, and other soil properties. The models predicted separate data sets that were not used in their development, indicating the success of the application of the dynamic cone penetration test in evaluating the resilient modulus of pavement subgrade soils.

Proceedings of Geo-Frontiers 2005, held in Austin, Texas, January 24-26, 2005. Sponsored by the Geo-Institute of ASCE. This Geotechnical Special Publication contains 16 papers covering contemporary foundation engineering issues including Load and Resistance Factor Design (LRFD) and reliability-based design for deep foundations; geosynthetic reinforced pile supported embankments; practical considerations for the design of foundations; problems and improvements pertaining to the Standard Penetration Test (SPT); and mat foundations.