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Investigationa NewCorrelation of ofTexasConePenetrometerValuesand ShearGenerationofTestFCCCompliantStrength of Texas Soils:NDT DevicesforReportPavementTechnicalLayer Information Collection TxDOT Project Report No. 0-4862-1Test Procedureand FacilityFinal ReportTexas Department of Transportationand 0-4820-2Technical ReportFederal Highway AdministrationbyC. VipulanandanPh.D., P.E.Performedin Cooperationwith theJ. Puppala Ph.D.,P.E.TexasA.Departmentof TransportationM. JaoHighwayPh.D., P.E.and the FederalAdministrationM.S.Kim 0-4820ProjectNumberH. VasudevanP. KumarandY. L. MoByPh.D.Richard LiuJing LiTXueminCI G M AChenAditya EkboteHuichun XingYing Wang1994Center for Innovative Grouting Materials and Technology(CIGMAT)Department of Civil and Environmental EngineeringUniversityof 04-4003Department of Electrical and Computer EngineeringUniversity of HoustonReport No. CIGMAT/UH 2007-4URL: August 2006Published:FebruaryJuly2006 2008http://tti.tamu.edu/documents/0-4862-1

Technical Report Documentation Page1. Report No.2. Government Accession No.3. Recipient's Catalog No.FHWA/TX-08/0-4862-14. Title and Subtitle5. Report DateCORRELATION OF TEXAS CONE PENETROMETER TESTVALUES AND SHEAR STRENGTH OF TEXAS SOILS:TECHNICAL REPORT7. Author(s)August 2006Published: February 20086. Performing Organization Code8. Performing Organization Report No.Vipulanandan, C., Puppala, A.J., Jao, M., Kim, M.S., Vasudevan, H.,Kumar, P., and Mo, Y. L.Report 0-4862-19. Performing Organization Name and Address10. Work Unit No. (TRAIS)University of HoustonDepartment of Civil and Environmental EngineeringN107 Engineering Building 1Houston, Texas 77204-400311. Contract or Grant No.Project 0-486212. Sponsoring Agency Name and Address13. Type of Report and Period CoveredTexas Department of TransportationResearch and Technology Implementation OfficeP. O. Box 5080Austin, Texas 78763-5080Technical Report1 Sep 2004 - 31 Aug 200614. Sponsoring Agency Code15. Supplementary NotesProject performed in cooperation with the Texas Dept. of Transportation and the Federal Hwy. Admin.Project Title: Correlation of Texas Cone Penetrometer Test Values and Shear Strength of Texas SoilsURL: http://tti.tamu.edu/documents/0-4862-1.pdf16. AbstractThis report discusses the correlation of Texas Cone Penetrometer (TCP) test values and shear strength ofTexas soils. Data collected over the past decade by the Texas Department of Transportation (TxDOT) fromseveral parts of Texas were used to verify the current correlation between TCP blow count and the undrainedshear strengths of clays with higher (CH) and low liquid limits (CL), sandy clay (SC) and Other soils. Over4000 sets of data were used to verify the current TxDOT relationships for the entire state of Texas and threeTxDOT districts from where most of the data were collected. Limited field studies were performed to verifythe current TxDOT relationship with CH and CL soils. Based on the data available and statistical analyses,linear and nonlinear relationships between undrained shear strength of soil and TCP blow count have beendeveloped. The statistical parameters including the probability distribution functions (PDF) for the undrainedshear strength (Su) and TCP blow count (NTCP ) based on the type of soil were determined. Analyses showedthat the current TxDOT design relationships overestimated the undrained shear strength (Su ) and TCP blowcount (NTCP ) was dependent on the depth for all types of soils investigated. The depth dependency also variedfrom location to location. The undrained shear strength versus TCP blow count relationships developed werealso influenced by the locations.17. Key Words18. Distribution StatementCorrelations, Shear Strength, Soils, StatisticalAnalyses, Texas Cone PenetrometerNo restrictions. This document is available to thepublic through NTIS:National Technical Information Service5285 Port Royal RoadSpringfield, Virginia 2216119. Security Classif.(of this report)20. Security Classif.(of this page)UnclassifiedUnclassifiedForm DOT F 1700.7 (8-72)Reproduction of completed page authorized21. No. of Pages20822. Price

Correlation of Texas Cone Penetrometer Test Valuesand Shear Strength of Texas Soils: Technical ReportTxDOT Project Report No. 0-4862-1Final ReportTexas Department of TransportationandFederal Highway AdministrationbyC. Vipulanandan Ph.D., P.E.A. J. Puppala Ph.D., P.E.M. Jao Ph.D., P.E.M.S. KimH. VasudevanP. KumarandY. L. Mo Ph.D.1994C I G MATCenter for Innovative Grouting Materials and Technology (CIGMAT)Department of Civil and Environmental EngineeringUniversity of HoustonHouston, Texas 77204-4003Report No. CIGMAT/UH 2007-4August 2006Published: February 2008

ENGINEERING DISCLAIMERThe contents of this report reflect the views of the authors, who are responsiblefor the facts and the accuracy of the data presented herein. The contents do notnecessarily reflect the official views or policies of the Texas Department ofTransportation. This report does not constitute a standard or a regulation.There was no art, method, process, or design which may be patentable under thepatent laws of the United States of America or any foreign country.v

PREFACEIn Texas, the Texas Cone Penetrometer (TCP) test is conducted during foundationexploration. Since the TCP test is routinely carried out and required for investigation offoundation materials encountered during geotechnical exploration for TxDOT projects, alarge amount of data from this test are available.Correlations based on the test values could be very useful to engineers todetermine the undrained shear strength of the soil and limited research was done in themid 1970s to correlate the TCP blow count ( N TCP ) to the undrained shear strength of soil( S u ). These studies were performed in the upper Gulf Coast region with limited numberof data. Hence, in order to verify the current correlations for soils from different regionsof Texas, a research study was initiated at three universities: The University of Houston,Lamar University and The University of Texas at Arlington.The main objective of this study was to verify the current design relationship usedby TxDOT to determine the undrained shear strength of soil from TCP blow count and, ifnecessary, develop correlations based on the data collected.In this study, Texas was divided into three sectors to collect the data and the datawere collected from TxDOT projects over the past decade (1994 - 2004) and analyzed.Over 4000 sets of data were collected on CH, CL, SC and Other soil types and used in theanalyzes. Collected data were verified with the current TxDOT relationships for each soiltype for the entire state and for a few TxDOT districts with large amounts of data. Datawere statistically analyzed for each blow count. Linear and nonlinear relationshipsbetween TCP blow count and undrained shear strength have been developed. Deptheffect (influenced by geology and active zone) on blow count and shear strength wasinvestigated.This report summarizes the verification of the current TxDOT designrelationships and developed new relationships between the undrained shear strength ofvarious soils and TCP blow count based on the data collected by TxDOT.vi

ABSTRACTSince the Texas Cone Penetrometer (TCP) tests are routinely performed duringany foundation exploration for the Texas Department of Transportation (TxDOT), a largeamount of data has been collected over the past decades. Correlations based on the blowcounts and soil types are currently used to determine the undrained shear strength of thesoils. Limited research was done in the mid 1970s to correlate the TCP blow counts to theundrained shear strength of soil, especially for soil in the Upper Gulf Coast region.In this study, data collected over the past decade by TxDOT were used to verifythe current correlations between the TCP blow count and the undrained shear strengths ofCH, CL, SC and Other soils. Over 4000 sets of data were used to verify the currentTxDOT relationships and the data were collected from four TxDOT districts. Limitedfield studies were performed to verify the current TxDOT relationship with CH and CLsoils.Analysis of the data showed that, as compared to other soils, CL soils had bettercorrelation with the current TxDOT Method. Based on the data available and statisticalanalyses, linear and nonlinear relationships between the undrained shear strength of soiland the TCP blow count have been developed. The statistical parameters including theprobability distribution functions (PDF) for the undrained shear strength ( S u ) and TCPblow count ( N TCP ) based on the type of soils were determined. Based on the analysis ofdata for every TCP blow count ( N TCP ), the predominant probability distribution function(PDF) for S u was lognormal. Analysis of the data also showed that the depth affected theTCP blow count. Validation analysis with about 1% of the data (about 50 data sets)collected from this study showed that the TxDOT relationship over predicted the leastamount of data compared to the other relationships investigated in this study.The study was completed in two years and was a joint effort among researchers atUniversity of Houston, University of Texas at Arlington and Lamar University.vii

SUMMARYThe Texas Cone Penetrometer (TCP) is a sounding test similar to the StandardPenetration Test (SPT) and Cone Penetration Test (CPT) used to determine the in situ soilparameters for foundation design. In the case of the TCP test, the potential energyresulting from the hammer impact is similar to the SPT test. The cone shape and apexangle of the TCP are similar to the CPT but the diameter is larger. Therefore, it can bestated that the TCP is a hybrid of the SPT and the CPT, and can be used in all types ofsoils. The TCP test is a standardized test procedure currently used by the TexasDepartment of Transportation (TxDOT) for geotechnical studies to indirectly estimate thein situ undrained shear strength of soils (TxDOT Geotechnical Manual, 2000).The objective of this project was to verify the current design relationship used byTxDOT to determine the undrained shear strength of soil from TCP blow count and todevelop correlations with high level of confidence based on the data collected. Theparameters investigated were soil types, depth and locations. The objectives wereachieved by collecting data from TxDOT projects over the past decade (1994 - 2004) bythree universities—The University of Houston, Lamar University and University ofTexas at Arlington—together with limited field study and laboratory tests on the soilsamples collected for the field. Over 4,000 data sets (TCP blow count ( NTCP ) andundrained shear strength ( S u ) were collected from 3,987 bore holes from past TxDOTprojects. The cumulative length of the bore holes was 177,298 ft. Of the over 4,000 datasets, 2,100 data sets were identified as CH soils, 1,852 data sets were identified as CLsoils, 29 data sets were identified as SC soils, and 42 data sets were identified as Othersoils.Collected data were compared to the current TxDOT S u versus N TCP relationshipfor each soil type and analyzed based on statistical methods and theoretical concepts inthis study. Also, limited tests were done to validate the data. The relationship between N 1and N 2 was also investigated based on the soil type. A total of three approaches wereused to develop new correlations between S u versus N TCP . The first attempt was toinvestigate directly the S u versus N TCP relationship, the second was to consider theviii

average strength ( S u ) for each TCP blow count ( N TCP ), and in the final attempt deptheffect on the mean N TCP ( N TCP ) and mean S u ( S u ) was considered.All the analyses were based on soil type. For the CH soil, based on 2100 data sets,the undrained shear strength ( S u ) varied from 0.45 to 88.75 psi with a mean of 16.8 psi.The coefficient of variation (COV) was 67%, which was the highest for the soilsinvestigated in this study. The probability distribution function (PDF) for the undrainedshear strength ( S u ) was lognormal. The TCP blow count ( N TCP ) varied from 2 to 100 witha mean of 31. The COV was 70%, which was the highest for the soils investigated in thisstudy. The PDF for the TCP blow count ( N TCP ) was lognormal. Current TxDOTrelationship over predicted 59% of the data for the CH soils. For the CL soil, based on1852 data set, the undrained shear strength ( S u ) varied from 0.96 to 114.6 psi with amean of 12.9 psi. The COV was 54%, which was the lowest for the soils investigated inthis study. The PDF for the undrained shear strength ( S u ) was lognormal. The TCP blowcount ( N TCP ) varied from 2 to 100 with a mean of 35. The COV was 58%. The PDF forthe TCP blow count ( N TCP ) was lognormal. For the SC soil, based on 29 data set, theundrained shear strength ( S u ) varied from 3.5 to 38.55 psi with a mean of 10.8 psi. TheCOV was 60%. The PDF for the undrained shear strength ( S u ) was lognormal. The TCPblow count ( N TCP ) varied from 7 to 87 with a mean of 30. The COV was 66%. The PDFfor the TCP blow count ( N TCP ) was Weibull. For the other soil, based on 42 data set, theundrained shear strength ( S u ) varied from 1.4 to 69.3 psi with a mean of 16.8 psi. TheCOV was 66%. The PDF for the undrained shear strength ( S u ) was Weibull. The TCPblow count ( NTCP ) varied from 10 to 93 with a mean of 45. The COV was 45%, whichwas the lowest for the soils investigated in this study. The PDF for the TCP blow count( NTCP ) was normal.Based on the analyses of raw data and average values, linear and nonlinearrelationships were developed from three attempts. Analyses showed that the currentTxDOT design relationships overestimated the undrained shear strength ( S u ) and TCPblow count ( NTCP )depended on the depth for all the types of soils investigated. The depthix

dependency also varied from location to location. The undrained shear strength versusTCP blow count relationships developed were also influenced by the locations.RESEARCH STATEMENTThis research project was to verify the current correlations used by TxDOT todetermine the undrained shear strength of soils using the Texas Cone Penetrometer blowcounts. Over 4000 data sets collected over the past decade were used in this study. Basedon this study, the current TCP correlation better predicted the undrained shear strength ofCL soils compared to the other soils.This report will serve as a guidance document for TxDOT engineers on using theTexas Cone Penetrometer blow count to better predict the shear strength of soils in Texasusing the correlations developed in this study. Also, local correlations have beendeveloped for a few areas.x

TABLE OF CONTENTSPageLIST OF FIGURES . xvLIST OF TABLES. xixCHAPTER 1. INTRODUCTION . 11.1 Introduction. 11.2 Research Objectives. 21.3 Organization. 3CHAPTER 2. LITERATURE REVIEW . 52.1 Introduction. 52.2 Penetrometers. 82.2.1 Standard Penetration Test (SPT). 92.2.2 Cone Penetration Test (CPT) . 102.2.3 Texas Cone Penetrometer (TCP) . 102.3 TCP and Shear Strength. 142.4 Review of Past Research on TCP . 152.5 Texas Geology . 182.5.1 Houston-Beaumont Area . 182.5.2 Dallas-Forth Worth Area . 212.6 Summary . 23CHAPTER 3. DATA COLLECTION AND ANALYSIS. 253.1 Database System . 253.1.1 Soil Database Management System (SDBMS). 25xi

3.1.2 Data Collected. 313.1.3 TCP and Shear Strength Data . 343.2 Data Correlation. 393.2.1 Total Soil Data Analysis . 443.2.2 Local Soil Data Analysis for Houston District . 473.2.3 Local Soil Data Analysis for Beaumont District . 543.2.4 Local Soil Data Analysis for Dallas-Fort Worth District . 573.3 Comparison of Correlations. 613.4Validation. 613.4.1 Houston District . 613.4.2 Dallas-Fort Worth District . 643.5 Relationships between N 1 and N 2 . 673.5.1 Total Soil Data Analysis . 673.5.2 Local Data Analysis for Houston District. 713.5.3 Local Data Analysis for Beaumont District. 733.5.4 Local Data Analysis for Dallas-Fort Worth District. 743.6 Summary . 76CHAPTER 4. STATISTICAL ANALYSIS . 814.1 Total Soil Data Analysis . 834.1.1 Total CH Soil . 834.1.2 Total CL Soil. 854.1.3 Total SC Soil. 864.1.4 Total OTHER Soils. 90xii

4.2 Local Soil Data Analysis . 914.2.1. Houston District . 91(a) Houston CH Soil. 94(b) Houston CL Soil. 95(c) Houston SC and OTHER Soils. 964.2.2 Beaumont District . 97(a) Beaumont CH Soil. 97(b) Beaumont CL Soil. 1004.2.3 Dallas-Fort Worth district . 101(a) Dallas-Fort Worth CH Soil. 101(b) Dallas-Fort Worth CL Soil. 1034.3 Mean Undrained Shear Strength ( S u ) Analysis. 1044.3.1 Total Data Analysis. 1044.3.2 Local Data Analysis (Houston District):. 1114.3.3 Local Data Analysis (Beaumont district). 1134.3.4 Local Data Analysis (Dallas-Fort Worth District). 1154.4 Summary . 118CHAPTER 5. DEPTH EFFECT ANALYSES . 1235.1 Factors Affecting Resistance to Penetration, NTCP . 1245.2 Depth Effect . 1255.3 Model-4. 1275.4 Total Soil Data Analysis . 1285.4.1 CH Soil. 128xiii

5.4.2 CL Soil . 1325.4.3 SC Soil . 1365.4.4 OTHER Soil. 1405.5 Local Data Analysis for Houston District. 1445.5.1 CH Soil. 1445.5.2 CL Soil . 1485.6 Local Data Analysis for Beaumont District. 1535.6.1 CH Soil. 1535.6.2 CL Soil . 1565.7 Local Data Analysis for Dallas-Fort Worth District. 1615.7.1 CH Soil. 1615.7.2 CL Soil . 1645.8 Summary . 169CHAPTER 6. CONCLUSIONS AND RECOMMENDATIONS . 1736.1 Conclusions. 1736.2 Recommendations. 179REFERENCES . 181xiv

LIST OF FIGURESPageFigure 2.1 Comparisons of Penetrometers (a) SPT, (b) CPT and (c) TCP. 6Figure 2.2 Texas Cone Penetrometer (TCP). 13Figure 2.3 TCP Hammers (TxDOT Geotechnical Manual, 2000). 14Figure 2.4 Design Chart to Predict Shear Strength for Foundation Design Using - values;Presently Used by TxDOT (Geotechnical Manual, 2000). 17Figure 2.5 Texas Surface Geology. 22Figure 3.1 Structure of the Data Model for SDBMS.25Figure 3.2 Typical Drilling Log. 36Figure 3.3 Texas Borehole Locations . 38Figure 3.4 Point Bearing Relationship; Presently Used by TxDOT(TxDOT Geotechnical Manual, 2000) . 43Figure 3.5 Correlation Between S u and NTCP for CH Soils (Total Soil Data) . 48Figure 3.6 Correlation Between S u and N TCP for CL Soils (Total Soil Data) . 48Figure 3.7 Correlation Between S u and NTCP for SC Soils (Total Soil Data). 49Figure 3.8 Correlation Between S u and NTCP for Other Soils (Total Soil Data). 49Figure 3.9 Correlation Between S u and NTCP for CH Soils (Houston Soil Data) . 53Figure 3.10 Correlation Between S u and NTCP for CL Soils (Houston Soil Data) . 53Figure 3.11 Correlation Between S u and NTCP for CH Soils (Beaumont Soil Data) . 56Figure 3.12 Correlation Between S u and NTCP for CL Soils (Beaumont Soil Data). 56Figure 3.13 Correlation Between S u and N TCP for CH Soils (Dallas and Fort Worth SoilData). 60xv

Figure 3.14 Correlation Between S u and NTCP for CL Soils (Dallas and Fort Worth SoilData). 60Figure 3.15 Possible Trends Observed.61Figure 3.16 Data Validation (Houston District-CL Soil). 63Figure 3.17 Data Validation (Dallas District-CH Soil) . 66Figure 3.18 Data Validation (Dallas District-CL Soil). 66Figure 3.19 Correlation Between N 1 and N 2 for Total CH Soils. 69Figure 3.20 Correlation Between N 1 and N 2 for Total CL Soils . 69Figure 3.21 Correlation Between N 1 and N 2 for Total SC Soils . 70Figure 3.22 Correlation Between N 1 and N 2 for Total OTHER Soils . 70Figure 3.23 Correlation Between N 1 and N 2 for Houston CH Soils. 72Figure 3.24 Correlation Between N 1 and N 2 for Houston CL Soils . 72Figure 3.25 Correlation Between N 1 and N 2 for Beaumont CH Soils. 73Figure 3.26 Correlation Between N 1 and N 2 for Beaumont CL Soils . 74Figure 3.27 Correlation Between N 1 and N 2 for Dallas-Fort Worth CH Soils. 75Figure 3.28 Correlation Between N 1 and N 2 for Dallas-Fort Worth CL Soils . 75Figure 4.1 Probability Distribution Functions for NTCP and S u of Total CH and CL SoilData (a) NTCP for CH Soil (b) NTCP for CL Soil (c) S u (psi) for CH Soil and (d) S u(psi) for CL Soils . 88Figure 4.2 Probability Distribution Functions for NTCP and S u of Total SC and OTHERSoil Data (a) NTCP for SC Soil (b) NTCP for OTHER Soil (c) S u for SC Soil and (d)S u for OTHER Soils. 93Figure 4.3 Variation of Mean Undrained Shear Strength ( S u )with N TCP for CH Soil. 107xvi

Figure 4.4 Variation of Mean Undrained Shear Strength ( S u ) with NTCP for CL Soil . 108Figure 4.5 Variation of Mean Undrained Shear Strength ( S u ) with N TCP for SC Soil . 109Figure 4.6 Variation of Mean Undrained Shear Strength ( S u ) with N TCP for OTHERSoils. 110Figure 4.7 Variation of Mean Undrained Shear Strength ( S u )with N TCP for Houston CHSoils. 112Figure 4.8 Variation of Mean Undrained Shear Strength ( S u ) with N TCP for Houston CLSoils. 112Figure 4.9 Variation of Mean Undrained Shear Strength ( S u )with N TCP for Beaumont CHSoils.

Sep 01, 2004 · The Texas Cone Penetrometer (TCP) is a sounding test similar to the Standard Penetration Test (SPT) and Cone Penetration Test (CPT) used to determine the in situ soil parameters for foundation design. In the case of the TCP test, the potential energy resulting from the hammer impact is similar