Faculty of Civil Engineering Universiti Teknologi Malaysia

Transcription

1 A COMPARISON OF PILE PERFORMANCE BASE ON STATIC FORMULAS AND DYNAMIC LOAD TEST MUHD HARRIS BIN RAMLI A project report submitted in partial fulfillment of the requirements for the award of degree of Master of Engineering (Civil-Geotechnic) Faculty of Civil Engineering Universiti Teknologi Malaysia JULY, 2006

2 iv ABSTRACT Since the early of pile static formula suggested by Meyerhof (1956) up until now, several pile design method is being proposed. Between one method and another, result differences are still questionable. This study is conducted base on driven pile 300 mm diameter spun pile constructed in Malaysia on sand or fine soil. This is to determine the differences between several pile design methods by Meyerhof (1976), Janbu (1976), Vesic (1977), Coyle and Castello (1981), method (1985) and method (1972) with the End-bearing capacity and Skin Resistance capacity value from dynamic load test using Pile Driving Analyzer (PDA). All the design method is also analyzed by using soil friction angle correlation by Schmertmann (1975), Peck, Hanson and Thornburn (1974) and Hatanaka and Uchida (1996). From analysis it can be found that Meyerhof, Coyle and Castello, and method are the most conservative which its value lower or almost near the PDA value. Then follow by Janbu method and method which its value almost near PDA or slightly above it. Vesic method is found to be very unconservative which it value well above PDA value. From this study it can be conclude that it is recommended to use either Meyerhof or Janbu Method for estimating end-bearing capacity in sand and silt. For skin resistance in sand it recommended using Meyerhof method. Finally for estimating skin resistance in clayed soil it is recommended to use method.

3 v ABSTRAK Sejak daripada awal kewujudan formula static cerucuk yang telah dicadangkan oleh Meyerhof (1956), beberapa formula rekabentuk cerucuk telah dicadangkan oleh beberapa individu yang lain. Walaubagaimanapun perbezaan rekabentuk antara beberapa formula ini masih lagi menjadi tanda tanya. Kajian ini dijalankan berdasarkan cerucuk kelompang bersaiz 300 mm diameter yang telah ditanam di atas tanah berbutir halus dan berpasir di Malaysia. Kajian ini adalah untuk mengkaji perbezaan keupayaan galas dan geseran kulit cerucuk antara beberapa kaedah rekabentuk cerucuk oleh Meyerhof (1976), Janbu (1976), Vesic (1977), Coyle dan Castello (1981), kaedah (1985) dan kaedah (1972) dengan keupayaan cerucuk yang diperolehi daripada ujian beban cerucuk menggunakan Pile Driving Analyzer (PDA). Kesemua kaedah rekabentuk turut dianalisis menggunakan sekaitan sudut geseran tanah oleh Schmertmann (1975), Peck, Hanson dan Thornburn (1974), dan Hatanaka dan Uchida (1996). Daripada analysis, dapat dirumuskan bahawa kaedah, Coyle dan Castello, dan Meyerhof merupakan kaedah yang paling konsevatif kerana mempunyai nilai keupayaan yang rendah atau hampir dengan nilai PDA. Ini diikuti oleh kaedah dan kaedah Janbu yang mempunyai nilai yang hampir atau lebih sedikit daripada nilai PDA. Kaedah Vesic didapati merupakan kaedah yang paling tidak konservatif kerana mempunyai nilai yang agak tinggi berbanding dengan nilai daripada PDA. Daripada kajian ini dapat disimpulkan bahawa kaedah Meyerhof dan Janbu merupakan kaedah paling sesuai bagi analisis keupayaan galas tanah pasir dan kelodak. Bagi analisis keupayaan geseran kulit cerucuk ditanam di tanah pasir, kaedah Meyerhof merupakan yang paling sesuai. Akhir sekali, kaedah merupakan kaedah yang dicadangkan bagi analysis keupayaan geseran kulit cerucuk ditanam di tanah liat.

4 vi TABLE OF CONTENT CHAPTER TITLE PAGE TITLE DECLARATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF APPENDICES LIST OF SYMBOLS i ii iii iv v vi xi xiii xvi xviii CHAPTER I INTRODUCTION Introduction Objective Research Scope Importance of Study 4 CHAPTER II LITERATURE REVIEW Classification of Pile Load-bearing Characteristics 5

5 vii Pile Installation Method Selection of Pile Ground Condition and Structure Durability Piling Cost General Overview of Piled Foundation Design Factor of Safety Effects of Pile Driving in Clays Influence on Soil Shear Strength and 13 Pile Capacity Pore Pressure Developed during Driving Dissipation of Excess Pore Pressure Displacement Caused by Driving Effects of Pile Driving in Sands Single Piles Pile Groups 23 CHAPTER III METHODOLOGY Phase One Research Data Phase One Stage One Case Retrieval Phase One Stage Two 26 Information Retrieval Data Acquiring From Soil 26 Investigation Report Correlated Data from Soil 26 Investigation Report Data Acquiring From Pile Load 29 Test Report

6 viii Phase One Stage Three Analysis Information Preparation Phase Two Pile Design Pile End-Bearing Capacity (Q p ) Design in 30 Sandy Soil Meyerhof s Method (1976) for 31 Estimating (Q p ) in Sandy Soil Vesic s Method (1977) for 32 Estimating (Q p ) in Sandy Soil Janbu s Method (1977) for 33 Estimating (Q p ) in Sandy Soil Pile Skin Friction Capacity (Q s ) Design in 33 Sandy Soil Meyerhof s Method (1977) for 34 Estimating (Q s ) in Sandy Soil Coyle and Castello Method (1981) 35 for Estimating (Q s ) in Sandy Soil Pile Skin Friction Capacity (Q s ) Design in 35 Clay Method (1977) for Estimating (Q s ) in 35 Clay Method (1977) for Estimating (Q s ) in 37 Clay 3.3 Phase Three Research Analysis Phase Three Stage One 38 Comparison Between Redesign Load Carrying Capacity and Pile Driving Analyzer (PDA) Load Carrying Capacity Phase Three Stage Two 40 Accuracy Ratio Analysis

7 ix Phase Three Stage Three Design Parameter Relationship Phase Four Pile Design Guideline Phase Four Stage One 42 Relationship Analysis Phase Four Final Stage 42 Pile Design Method Recommendations CHAPTER IV RESULT AND DISCUSSION Sandy Soil Study Case Preparation of Analysis Data Direct Design Parameter Value Indirect Design Parameter Value End-Bearing Analysis for Sand Study Case Estimation of Theoretical End-Bearing 47 Capacity for Sand Soil Comparison of Theoretical 50 End-Bearing Capacity with Pile Driving Analyzer (PDA) End-Bearing Capacity for Sand Soil Relationship Analysis for Sand 52 End-Bearing Estimation Skin Resistance Analysis for Sand 57 Study Case Estimation of Theoretical 57 Skin Resistance for Sand Soil Comparison of Theoretical 59 Skin Resistance with Pile Driving Analyzer (PDA) Skin Resistance for Sand Soil

8 x Relationship Analysis for Sand Skin Resistance Estimation Fine Soil Study Case Preparation of Analysis Data Direct Design Parameter Value Indirect Design Parameter Value End-Bearing Analysis for Fine Soil 66 Study Case Estimation of Theoretical 66 End-Bearing Capacity for Silt Soil Comparison of Theoretical 68 End-Bearing Capacity with Pile Driving Analyzer (PDA) End-Bearing Capacity for Silt Soil Relationship Analysis for Silt 70 End-Bearing Estimation Skin Resistance Analysis for Fine Soil 72 Study Case Estimation of Theoretical Skin 72 Resistance for Clay Comparison of Theoretical 72 Skin Resistance with Pile Driving Analyzer (PDA) Skin Resistance for Clay Relationship Analysis for Clay 73 Skin Resistance Estimation CHAPTER V CONCLUSION 75 REFERENCES 77

9 xi LIST OF TABLES TABLE NO. TITLE PAGE 3.1 The group and classification for analysis in all study case Pile end-bearing design parameter value taken directly 44 from the report 4.2 Pile skin resistance design parameter value taken directly 45 from the report 4.3 Soil Friction Angle value correlated from SPT N value in 46 Soil Investigation Report for Sand End-Bearing Capacity analysis 4.4 Soil Friction Angle value correlated from SPT N value in 46 Soil Investigation Report for Sand Skin Resistance analysis 4.5 Pile design parameter value calculated from formula Sand theory End-Bearing analyzed used Meyerhof 48 (1976), Vesic (1977), and Janbu s Method (1976) for Group A Soil Friction Angle 4.7 Sand theory End-Bearing analyzed used Meyerhof 48 (1976), Vesic (1977), and Janbu s Method (1976) for Group B Soil Friction Angle 4.8 Sand theory End-Bearing analyzed used Meyerhof (1976), Vesic (1977), and Janbu s Method (1976) for Group C Soil Friction Angle 49

10 xii 4.9 Sand theory Skin Resistance analyzed used Meyerhof s Method (1977), and Coyle and Castello s Method (1981) for Group A Soil Friction Angle 4.10 Sand Skin Resistance analyzed used Meyerhof (1977), and Coyle and Castello s Method (1981) for Group B Soil Friction Angle 4.11 Sand Skin Resistance analyzed used Meyerhof (1977), and Coyle and Castello s Method (1981) for Group C Soil Friction Angle 4.12 Pile design parameter value taken directly from the report 4.13 Soil Friction Angle value correlated from SPT N value in Soil Investigation Report for Silt End-Bearing Capacity analysis 4.14 Silt theory End-Bearing analyzed used Meyerhof (1976), Vesic (1977), and Janbu s Method (1976) for Group A Soil Friction Angle 4.15 Sand theory End-Bearing analyzed used Meyerhof (1976), Vesic (1977) and Janbu s Method (1976) for Group B Soil Friction Angle 4.16 Sand theory End-Bearing analyzed used Meyerhof (1976), Vesic (1977) and Janbu s Method (1976) for Group C Soil Friction Angle Clay theory Skin Resistance analyzed used Alpha Method (1985) and Lamda Method (1972)

11 xiii LIST OF FIGURES FIGURES NO. TITLE PAGE 2.1 (a) End-bearing type of pile (b) Skin friction type of pile Classification of piling system according to the Code 7 of Practice for Foundation, BS 8004: Increase of load capacity with time (Soderberg, 1962) Theoretical solution for rate of consolidation near a 16 driven pile 2.5 Movement of nearby building caused by pile driving 19 operation 2.6 The contours of soil friction angle ( ) cause by 22 compaction of sand around driven pile 3.1 Study methodology flow chart Variation of the maximum values of N with soil 31 friction angle 3.3 Variation of with c u / o Variation of with pile embedment length Line Chart Theory Redesign value versus Pile 39 Driving Analyzer value 3.6 The line chart of Accuracy Ratio against Soil Friction 41 Angle 3.7 The line chart of Accuracy Ratio against Overburden 41 Pressure q

12 xiv 4.1 Theory End-Bearing vs PDA End-bearing graph for All Group 4.2 Theory End-Bearing vs PDA End-bearing graph for Group B 4.3 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for All Group 4.4 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for Group A 4.5 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for Group B 4.6 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for Group C 4.7 Theory End-Bearing / PDA Ratio vs Overburden Pressure for Group B 4.8 Theory End-Bearing / PDA Ratio vs Overburden Pressure for Group C 4.9 Theory Skin Resistance vs PDA Skin Resistance graph for Group A 4.10 Theory Skin Resistance vs PDA Skin Resistance graph for Group B 4.11 Theory Skin Resistance vs PDA Skin Resistance graph for Group C 4.12 Theory Skin Resistance / PDA Ratio vs Soil Friction Angle for all group 4.13 Theory End-Bearing vs PDA End-bearing graph for All Group 4.14 Theory End-Bearing vs PDA End-bearing graph for Group B 4.15 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for Group A 4.16 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for Group B

13 xv 4.17 Theory End-Bearing / PDA Ratio vs Soil Friction Angle for Group C 4.18 Theory Skin Resistance vs PDA Skin Resistance Ratio graph 4.19 Theory Skin Resistance / PDA Ratio vs Overburden Pressure graph

14 xvi LIST OF APPENDICES APPENDIX TITLE PAGE A Vesic N Value use in Pile End-Bearing Design 79 Analysis B / B-1 Summary Soil Investigation Report 81 B / B-2 Summary Pile Load Test Report PDA Test 105 C Detail Pile Design Parameter Value Calculation for Sand Study Case 115 D / D-1 Sand Pile End-Bearing Capacity Analysis Summary 120 D / D-2 Example Set 4/Group B Pile End-Bearing Detail Design 122 for Sand Study Case E Theory End-Bearing vs PDA End-Bearing Graph for Group A and Group C in Sand Study Case 126 F / F-1 Sand Pile Skin Resistance Capacity Analysis Summary 127 F / F-2 Example Set 4/Group B Pile Skin Resistance Detail 129 Design for Sand Study Case G Detail Pile Design Parameter Value Calculation for Fine Soil Study Case 133

15 xvii H / H-1 Silt Pile End-Bearing Capacity Analysis Summary 139 H / H-2 Example Set 4/Group B Pile End-Bearing Detail Design 141 for Fine Soil Study Case I Theory End-Bearing vs PDA End-Bearing Graph for Group A and Group C in Fine Soil Study Case 145 J Clay Pile Skin Resistance Capacity Detail Analysis Design 146

16 xviii LIST OF SYMBOLS SYMBOLS w Soil moisture content Unit weight of soil sat w c u L Unit weight of saturated soil Unit weight of water Undrained shear strength Pile penetration length L Pile critical depth (for skin resistance analysis) G s P a D r D 50 I rr Specified gravity of soil Soil vertical effective stress / overburden pressure Atmospheric pressure Soil relative density Soil friction angle Sieve size passing 50% in mm Soil-pile friction angle Reduced rigidity index for the soil

17 CHAPTER I INTRODUCTION 1.1 Introduction Pile foundations have been in use since prehistoric times. The Neolithic inhabitants of Switzerland drove wooden poles in the soft bottoms of shallow lakes 12,000 years ago and erected their homes on them (Sowers 1979). Venice was built on timber piles in the marshy delta of the Po River to protect early Italians from the invaders of Eastern Europe and at the same time enable them to be close to the sea and their source of livelihood. In Venezuela, the Indians lived in pile-supported huts in lagoons around the shores of Lake Maracaibo. Today, pile foundations serve the same purpose, to make it possible to build in areas where the soil conditions are unfavorable for shallow foundations. Although it dates back to prehistoric lake villages, until late nineteenth century, the design of pile foundation was based entirely on experience or even divine providence. Modern literature on piles can be said to date from the publication of the Engineering News (later to become the Engineering News-Record) in 1893, pile- driving formula was proposed (Poulos, H.G. 1980).

18 2 Since this first attempt at a theoretical assessment of the capacity of a pile, a great volume of field experimental and empirical data on the performance of pile foundation has been published. By now there is several design method can be use in pile design but only few is suitable use for practice. Although there is few of this design method, the value estimated different between one and another are still questionable. That which comes to the main interest of this study which method is suitable for a given condition. In this study which entitles A Comparison of Pile Performance Base on Static Formulas and Dynamic Load Test, the performance of pile on end-bearing capacity and skin resistance analysis will be study base on the Pile Driving Analysis (PDA) pile capacity value to be compared with several selected analysis method. 1.2 Objective This study aim is to give a guideline for pile designer to choose which method is suitable for a certain type of soil properties and condition. There is four objective in this study that need to be achieve in order to conclude which pile static formula suitable for a given soil condition: 1. To estimate theoretical pile end-bearing capacity (Q p ) and skin resistance capacity (Q s ) for each study cases. 2. To compare theoretical pile end-bearing capacity (Q p ) and skin resistance capacity (Q s ) from various pile static formula with dynamic load test on each study cases.

19 3 3. To determine the relationship between pile end-bearing capacity (Q p ) and skin resistance capacity (Q s ) ratio (Q (Theory) /Q (PDA) ), with effective vertical stress at the level of pile tip ( ) on each study cases. 4. To determine the relationship between pile end-bearing capacity (Q p ) and skin resistance capacity (Q s ) ratio (Q (Theory) /Q (PDA) ), with soil friction angle ( ) on each study cases. 1.3 Research Scope This research is base on the data obtain from Soil Investigation Report and Pile Load Test Report on construction Project in Malaysia. Only large displacement type of pile is consider in this studies because of the availability of data which can give a better analysis result. The type of pile selected for this research is limited to driven pile type 300 diameter spun pile. The load-carrying capacity of the pile point (Qp) and skin friction (Qs) data obtain from dynamic pile load test is using Pile Driving Analyzer (PDA) method. The estimation of theoretical load-carrying capacity of the pile point (Q p ) is analyze using three type of method which are Meyerhof s Method (1976), Vesic s Method (1977), and Janbu s Method (1976). Whereas the skin friction (Qs) is analyzed using Meyerhof s Method (1976) and Coyle and Castello Method (1981) for sand and for clayey soils, analysis is using Method (1985) and Method (1972). The selection of these analysis methods is base on the most preferable design method use in Malaysia pile design practice.

20 4 1.4 Importance of Study This study importance because pile and soil interaction is not an easy knowledge to be fully understand, even from the very earliest pile formulation studies by Meyerhof (1956) up until now, still consider as an estimated value. With the various pile static formula nowadays, the different between one method and another cause a lot of uncertainties which contributing higher safety factor. A higher safety factor in a design mean, a utilization of a larger pile cross section which laterally cause an unnecessary larger piling cost. At a worst case, a proposal of a vital project has to be turn down just because of the piling cost is unreasonable compare to the superstructure itself.

21 77 REFERENCES Bengt B. Broms (1978), Precast Piling Practice, Royal Institute of Technology, Stockholm Braja M. Das (2004), Principles of Foundation Engineering, Fifth Edition, Thomson Brooks / Cole, US Bustamante M. (1982), Foundation Engineering, Volume 1: Soil Properties Foundation design and construction, Presses Ponts et chausses, Paris Craig R.F (1993), Mekanik Tanah, Edisi Keempat, Unit Penerbitan Akademik Universiti Teknologi Malaysia, Johor Bahru Curtis W.G, Shaw G., Parkinson G.I. and Golding J.M. (2000), Structural Foundation Designers Manual, Blackwell Sciences Ltd, Oxford Joseph E. Bowles (1997), Foundation Analysis and Design, Fifth Edition, The McGraw-Hill Companies, Inc., US Nathabandu T. K. and Renzo R. (1997), Statistics, Probability, and Reliability for Civil and Environmental Engineers, The McGraw-Hill Companies, Inc., New York

22 78 Poulos H.G and Davis E.H (1980), Pile Foundation Analysis and Design, John Wiley & Sons, Inc., Canada Roy E. Hunt (1983), Geotechnical Engineering Investigation Manual, McGraw- Hill Book Company, New York William P. (1997), Soil Mechanics; Concept and Applications, Chapman & Hall, London