King Saud University College of Engineering Civil Engineering Department DEFORMATION OF PARTIALLY SATURATED SAND. Sultan Musaed Al-Ghamdi

Transcription

1 King Saud University College of Engineering Civil Engineering Department DEFORMATION OF PARTIALLY SATURATED SAND By Sultan Musaed Al-Ghamdi Submitted in Partial Fulfillment of The Required For the Degree of Bachelor of Science in Civil Engineering In The College of Engineering RIYADH

2 We hereby approve the report entitled: "DEFORMATION OF PARTIALLY SATURATED SAND" Prepared by Mr. Sultan M. Al-Ghamdi COMMITTEE MEMBERS: Advisor: signature: Prof. Hussain A. Alawaji Examiner: signature: Dr. Abdul Mohsin Al-Dhuyan Date:

3 LIST OF CONTENTS ABSTRACT CHAPTER 1 INTRODUCTION 1.1 GENERAL 1.2 OBJECTIVE OF THE PROJECT CHAPTER 2 LITERATURE REVIEW 2.1 IMPORTANCE OF SITE INVESTIGATION 2.2 THE INFORMATION SHOULD BE OBTAINED FROM SITE INVESTIGATION 2.3 METHODS OF SUBSURFACE EXPLORATION IN-SITU OF SOIL Test pits Soil Boring CHAPTER 3 FIELD AND LABORATORY WORK 3.1 GENERAL 3.2 LOCATION AND DESCRIPTION 3.3 FIELD TRIP FIELD INVESTIGATION BOREHOLE DRILLING (SPT) CONE PENTRATION TEST (CPT) LABORATORY TESTING OF FIELD WORKING UNIT WEIGHT LABORATORY TESTING 3.4 FIELD WORK FIELD DENSITY TEST COLLECTION OF SOIL SAMPLE 3.5 LABORARTARY SOIL PROGRAM PARTICLE SOIL SIZE SPICIFIC GRAVITY UNIT WEIGHT LABORATORY TESTING CHEMICAL ANALYSIS OF SOIL PLATE LOAD TEST CHAPTER 4 TEST RESULT AND DISCUSSION 4.1 PHYSICAL TEST RESULT PARTICAL SIZE ANALYSIS SPECIFIC TEST RESULT 4.2 CHEMICAL TEST ANALYSIS 4.3 IN SITU TEST TESTING 4.4 PLATE LOAD TSET CHAPTER 5 CONCLUSION REFRENCE APPENDIX A LABORATORY TEST

4 APPENDIX B FIELD TEST ABSTRACT

5 This project presented a study to evaluate the Deformation of partially saturated sand, carried out using instrumental plate load test. Specifically, an investigation in to the effects of water content with constant relative density on the stress settlement behavior is made. Laboratory model was constructed in order to investigate the level of settlement of circular plate (12.5cm) diameter on partially saturated sand, circular steel box 45 cm internal diameter and 35 cm height. The results of tests reported here relate to only one type of sand (AL JUBAIL SAND), the specimens were prepared by mixing the sand with water at vary of water content at constant dry sand density Kn/m³ with changing water content the stresses founded vary with water content at 2.5% maximum stress was 935.4kpa, at 5% it was kpa, at 7.5% it was kpa, at 10% it was %, at 12.5% it was kpa, and a 15% it was 771.1kpa. CHAPTER 1

6 INTRODUCTION 1.1 GENERAL A site geotechnical investigation is essential and before the construction of any project beings. Many governmental and private buildings were damaged because of lack or inadequate geotechnical investigation. Cracks due to excessive settlements in soil or complete failure due to insufficient bearing capacity of soil or rock. These damages could have been avoided should the necessary steps have been taken to make thorough investigation for underling soil or rock strata. So the site investigation in one form or another is always required for any engineering or building structure. This investigation can be done as a simple examination of surface soils with few shallow trial pits, or as a detailed study of the soil and ground water conditions to a considerable depth below the surface by means of boreholes and in-situ and laboratory tests on the material encountered. The extent of investigation work depends on the nature and importance of structure. By the site investigation, it is possible to know the suitability of the site for the proposed structure, to prepare an adequate and economic design for foundations, whatever its type, and to predict the problems that may be faced during construction such as water table rising, weathering of rock or cavities. In addition the site investigation may be applied to examine the safety of an existing structure or investigate a case where failure has occurred. 1.2 OBJECTIVE OF THE PROJECT

7 The main objective of this study is to investigate and determine the bearing capacity and settlement of the partially saturated Al Jubail sand and the effect of water content at constant sand relative density on the ultimate bearing capacity of shallow foundation. CHAPTER 2 LITERATURE REVIEW

8 2.1 IMPORTANCE OF SITE INVESTIGATION A site investigation is the first step required for any engineering or building structure. The investigation may range in scope from simple examination of these soils with or without trial pits to a detailed study of the soil and ground water conditions to a considerable depth below the surface by means of boreholes and in situ and laboratory tests on the material encountered. The extent of the work depends on the size and the importance of the proposed project, the time available for investigation, the cost of investigation in relation to the cost of the project and complexity of the soil condition. So, the main objects of site investigation can be defined as follows: 1- To assess the general suitability of the site for the proposed work. 2- To enable an adequate and economic design to be prepared. 3- To foresee and provide against difficulties that may arise during construction due to ground and, or other local conditions. 4- To investigate the occurrence or causes of all national or created changes of conditions. In addition the site investigation also applied to examine the safety of an existing structures or to investigate the cause of any failure in them.[1] 2.2 THE INFORMATION SHOULD BE OBTAINED FROM SITE INVESTIGATION

9 The following information s should be obtained in the course of site investigation for foundation engineering purposes: a) The general topography of the site as it affects foundation design and construction. b) The location of buried services such as electric power, telephone cables, water mains and sewers. c) The possibility of earthquakes or climate factors such as flooding, soil erosion, seasonal swelling and shrinkage. d) The nature, thickness, and dip of all soil strata within the zones affected by foundation bearing pressure. e) The different data of soil parameters and soil properties so that earth pressure and construction method may be evaluated. f) Ground water condition, including the level and seasonal variation of the water table and the pressure in the soil water. g) Results of laboratory tests on soil and rock samples appropriate to the particular foundation design or construction problems. h) Bearing capacity of the sub-surface soil at different depths, the results of chemical analysis on soil and deformation characteristics of the ground under different types of loading. In other words, a complete picture should be well known and studied about the site before starting the design and construction.[7] 2.3 METHODS OF SUBSURFACE EXPLORATION

10 Methods of determining the stratification and engineering characteristics of subsurface soil are: Test pits : A test pit is simply a hole dug in the ground that is large enough so that the succession of strata can be examined on the wall of the pit. Also ground water conditions can be established and undisturbed soil samples are obtainable relatively easily Soil Boring: a) Auger Boring: It is a hole advanced is use of hand or power auger. This may be used in clay soils to a depth of about 5meters. Disturbed samples may be obtained from the soil brought up in the auger and small undisturbed samples may be taken from bottom of the hole. b) Wash Boring : In this method the soil is loosened by high pressure water jet from a pipe passing down the borehole. This method cannot be used in large gravels or soil containing boulders. It is best suited for uniform sand or clays. c) Shell and Auger Boring : This method can be carried out in all types of soil since the boreholes can be lined where required with steer casing tubes, and wide variety of tools are used for different soil and rock types.[6,3] IN-SITU TESTING OF SOIL

11 Tests to determine the in-situ shear strength, permeability and density of soils are valuable means of investigation since these characteristics can be obtained directly without the disturbing effect of boring or sampling, the most important of these test are: a) Vane shear test b) Standard penetration test c) Static cone penetration test d) Plate load test e) Field permeability test f) Field density test[2]

12 CHAPTER 3 FIELD AND LABORATORY WORK 3.1 GENERAL To investigate the nature and properties of the soil at the site of the proposed project in Al-JUBAIL city, a field and a laboratory testing program was carried out. 3.2 LOCATION AND DISCRIPTION OF THE SITE The site is located in Al-JUBAIL city about 500 kilometers east north of Riyadh. The investigated site is located on the west, east and south side of Jubail 1 and passes through the industrial area. The corridor run almost adjacent to water channel. The topography of the project site is relatively flat with some sabkha zones found along the length of corridor. The vicinity map of the site is shown in Fig.3.1. Periodic submergence of the gulf coast in tertiary period resulted in deposition of over consolidated clays, closely interbedded sandstone and limestone. Uncemented quarternary and recent sediments, commonly consisting of Sabkha and dune sands overlie the Tertiary deposits. This lithology was confirmed by present geotechnical investigation of the sites. As per royal commission guidelines the area under study falls in earthquake, there is no potential for liquefaction of soil. The granular materials encountered in all the boreholes were composed of poorly graded sand (SP), poorly graded Gravel with silt and sand(gp-gm) and silty sand (SM according to USCS). Based on SPT N values these materials can be described as medium dense to dense in conditions. See details in boring logs shown in Tables Appendix B.

13 Figure 3.1 The Site Map of The Project in Al-Jubail Industrial City

14 3.3 FIELD TRIP Visiting Al-Jubail city has been included to be part of the project in order to get the information that talks about soil and foundation. In one of the companies locations, pipe line infra structure has given good examples that have been taken to Riyadh and do some experiences with them. In Al-Jubail, the field density cone method test has been done. As a result, sufficient information has been taken about standard penetration test (SPT), cone penetration test(cpt) and the physical properties for the soil as it mentioned in appendix B Field Investigation The proposed field work consisted of exploratory drilling, sampling, and cone penetration testing (CPT) of subsurface soil and excavation of the test pits. The investigation location were decided by client and marked in the field by RGME (Rashid Geotechnical& Material Engineers) A list of coordinate of Bore holes, and CPT's Borehole Drilling (SPT) The drilling of borehole was carried out using ACKER ADII drilling rig. The sub subsurface stratum was penetrated by rotary drilling method using wash boring technique. Standard penetration tests (SPT's) were performed at 1.0m intervals down to 6.0m and at 1.5m depth intervals thereafter. These tests were performed generally in accordance with ASTM D 1568 using split spoon of 35mm inner diameter. And 50mm outer Diameter. The samples recovered from split spoon sampler were visually inspected and classified as per ASTM D 2488.A description of soil samples recovered and the number of blows of the standard hummer used in SPTs for successive 15cms of penetration was recorded on field borehole logs. All the samples recovered from split spoon samplers were carefully preserved and sent t laboratory for further evaluation and testing. The borehole logs were prepared in the field. These logs were finalized after laboratory testing, and presented in Appendix B.

15 3.3.3 Cone Penetration Test (CPT) The static Cone Penetration Test (CPT), also known as Dutch cone soundings, was carried out using 20 ton machine. The test carried out by static, hydraulic pushing of standard 60 degree cone of 10 cm² area. The connected to the CPT rods and pushed statically into ground. Readings are taken at every 20cm depth intervals for the cone-tip resistance and side sleeve friction of the cone. The field readings are plotted on graph Laboratory Testing of Field Working The sample retrieved from boreholes were examined in the field and then transported to them laboratory testing. The laboratory tests were conducted on selected soil samples to determine the engineering characteristics of the subsurface strata. A summary of laboratory test performed at Appendix B. 3.4 FIELD WORK Field Density Test To determine the density of the soil in situ two tests were carried out using sand cone method according to ASTM D The test was performed at 1.5m depth. Plate 3.1to 3.3 shows the field density performance. The field density test results were in average KN/m³ Collection of Soil Samples A representative disturbed and block samples were carefully selected and taken from 6m depth. The soil samples were brought to the soil laboratory in the College of Engineering Civil Department KSU.

16 Plate3.1 cone method test Plate3.2 cone method test- hole Plate3.3 cone method test- white sand(ottawa sand)

17 3.5 LABORATORY SOIL PROGRAM Laboratory tests were performed on representative soil sample to evaluate their principal physical, engineering characteristics and their chemical properties. Following is the brief account of the testing program in the laboratory: Particle Size Analysis Tests The particle size analysis is very important to determine the relative proportions of different grain sizes which make up a given soil mass. Both sieve analysis and hydrometer tests were conducted on representative two soil samples in accordance with ASTM Specification D and D Specific Gravity (G s ) Specific gravity is an important property which used in the determination of other soil properties such as unit weigh, void ratio, porosity and other properties. This test was carried out in accordance of ASTM D UNIT WEIGHT The unit weight of sub surface soil can be estimated through interpretation of SPT data, CPT data and laboratory classification of the samples retrieved from boreholes. The relationship on N-value with typical submerged and bulk unit weight of cohesive and non-cohesive soil LABORATORY TESTING The samples retrieved from boreholes were examined in the field and then transported to testing laboratory for relevant laboratory testing. The laboratory tests were conducted on selected soil samples to determine the engineering characteristics of the subsurface strata.

18 3.5.5 CHEMICAL ANALYSIS OF SOIL Representative soil samples were prepared for chemical analysis. P h values, sulphate and chloride contents were determined in order to know their potential aggressiveness, the results from AL HOTY STANGER laboratory PLATE LOAD TEST Laboratory model load test were conducted using Perspex circular model foundation of 12.5cm diameter and 2 cm thickness used it for light weight. The test were carried out in a circular- steel box of 45cm internal diameter, 35 cm height, two displacement transducers for measuring settlement to take average settlement, with the extension rod directly on the model footing connecting with load cell for measuring load and data logger for recording the values of settlement and load. To have homogeneous soil sample, firstly, the initial water content of the soil was determined. The amount of water required to raise the water content to a predetermined value was added and thoroughly mixed to have homogeneous distribution of moisture. The soil was compacted in the container in three layers of 10 cm height. The weight of each layer was determined according to the dry density 29 kg. This weight was compacted with a uniform load until the desired height is obtained. Then the second and third layers were compacted with the same procedure of the first layer. The compacted soil in the container. The soil container was mounted on the compression machine. The set up of the test was completed by fixing the load cell for measuring the load and two displacement transducers for measuring settlement with the extension rod directly on the model footing. The test was run at loading rate of 0.3 mm/min. The readings were taken by the data logger model. The setup of the test is shown in plate 3.4 and 3.5.

19 Plate: 3.4 Set Up of The Test Plate: 3.5 set up of the test after testing

20 CHAPTER 4 TEST RESULTS AND DISSCUSION 4.1 PHYSICAL TEST RESULTS The laboratory test results obtained from the testing program the results with details shown in Appendix A. Here in this chapter are shown the results of tests directly, physically tests and the main test Plate Load Test (Bearing Capacity Test). Physically test such as sieve analysis, Field density test, water content.etc Particle Size Analysis Results : The grain size distribution curves are shown in Figure 4.1 and 4.2. According to these results and by using the plasticity chart for Unified Soil Classification System the tested soil can be classified as SP-SM poorly graded sand silty sand. According to AASHTO the tested soil is classified as (A-3) Specific Test Results : The specific test results of tested soils was in average 2.67 The summary of physical and engineering characteristics of tested soil are summarized in Table 4.1.

21 Table: 4.1 Physical and Engineering Characteristics of tested Soil Soil Properties Sample # 1 Sample # 2 Field density, KN/m Field water content, % Wet density, KN/m³ γ max gm/cm³ γ min gm/cm³ Specific Gravity, G s Gravel, % Sand, % % Passing # 200 Sieve C u C z D D D D Unified Soil Classification System SP-SM SP-SM AASHTO Soil Classification System A-3 A-3

22 4.2 CHEMICAL TEST RESULTS The chlorides and sulphate test results are listed in Table 4.2. The results from Al- HOTY STANGER laboratories. Table: 4.2 Chemical Test Results Sample Reference Depth (m) Sulfate (%) Chloride (%) PH B B

23 % Passing D60 D50 D D Grain Diam.(mm) Fig. 4.1 Grain size distribution curve(sample B) % Passing D60 D50 D D Grain Diam.(mm) Fig. 4.2 Grain size distribution curve (Sample E)

24 4.3 IN SITU TESTING In practice, the local geotechnical farms rarely perform plate load test and they commonly use the standard penetration test (SPT) to estimate different geotechnical parameters including bulk density, modulus of elasticity, modulus of sub grade reaction (etc), this approach is not accurate and gives very crude data. See Appendix B 4.4 PLATE LOAD TEST This test method covers estimation of the bearing capacity of soil in place by means of laboratory loading tests. This test method can be used as part of a procedure for soil investigation for foundation design. It gives information on the soil only to a depth equal to about two diameters of the bearing plate, and takes into account only part of the effect of time. Then loaded with slow rate by 0.3 mm/min until reach to 12.5mm which represent 0.1 the footing diameter as given from test shown in fig 4.3.and table 4.3 The details of test results shown in Appendix A. Note : the results and discussion COMPLETE>>>>>>>>

25 0 Vertical Stress, kpa Settlement, mm Plare load test # 1 Dry density =17.66 KN/m³ Water content =9.33% Plate = Diam. = 12.5 cm thick. = 2.0 cm Area = cm² 14 Figure4.3. Vertical Stress vs. Settlement from plate load test (Al-Jubail sand)

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27 THE NEXT SEMSTER TESTING PROGRAMS in next semester, I study direct shear for sand to estimate direct shear parameters at different relative densities. Plate load test, I study it at different relative density to estimate bearing capacity of sand.

28 CHAPTER 5 CONCLUSION Based on field data and laboratory test results completed to date, the following conclusion can be drawn: 1- The subsurface exploration shows that the upper layers of the project area comprise dune sand which is mostly light brown to brown in color and classified as poorly graded sand with silt (SP-SM) according to unified soil classification system, and (A- 3) at AASHTO system. 2- The in situ field density and field moisture content various from ( to KN/m³) and (6.13 to 9.33%) respectively. 3- The laboratory and field maximum density and minimum density vary from (1803 to 1831Kg/m³) and(1425 to 1582Kg/m³). 4- The in situ and laboratory specific gravity vary between 2.49 to 2.65.

29 REFERANCE [1] Braja M. Das(1995). " principles of Foundation Engineering" (PWS publishing company). [2] Joseoh E. Bowles, "Foundation Analysis and Design" Hand book. [3] Geotechnical Investigation Reports prepared by SAUDI Bin Laden, RGME. [4] Physical Properties by Al-Hoty STANGER [5] 194.htm?E+mystore (web site) [6] eb site) [7] Hunt, R.E, "Geotechnical Engineering Investigation Manual" McGraw-Hill Book Company-USA.

30 APPENDIX A

31 FIELD DENSITY TEST SAND CONE METHOD Sand Cone Apparatus No. B Date of Test 13/10/1428 H Test No. 2 Test Location AL JUBAIL INDUSTRIAL Material Sand Layer Designation 6m depth Volume of Test Hole 1. Weight of apparatus filled with sand gm 2. Weight of apparatus and remaining sand gm 3. Weight of sand in whole, plate and cone gm 4. Weight of in cone and plate gm 5. Weight of sand in whole gm 6. Bulk density of sand 1.5 gm/cc 7. Volume of test hole cc Density 8. Weight of moist soil from hole plus tare gm 9. Weight of tare gm 10. Weight of moist soil gm 11. Wet Density 1.93 gm/cc 1.93*9.8= Kn/m 3 Moisture Content and Dry Density 12. Weight of wet sample plus tare gm 13. Weight of dry sample plus tare gm 14. Weight of Water in sample gm 15. Tare number and Weight No. # gm 16. Weight of dry soil gm 17. Moisture content 6.13 % 18. Dry density KN/m 3

32 FIELD DENSITY TEST SAND CONE METHOD Sand Cone Apparatus No. E Date Of Test 13/10/1428 H Test No. 1 Test Location AL JUBAIL INDUSTRIAL Material Sand Layer Designation 6m depth Volume Of Test Hole 1. Weight of apparatus filled with sand gm 2. Weight of apparatus and remaining sand gm 3. Weight of sand in hole, plate and cone gm 4. Weight of in cone and plate gm 5. Weight of sand in hole gm 6. Bulk density of sand 1.5 gm/cc 7. Volume of test hole cc Density 8. Weight of moist soil from hole plus tare gm 9. Weight of tare gm 10. weight of moist soil gm 11. Wet Density 1.97 gm/cc 1.97*9.8= Kn/m 3 Moisture Content and Dry Density 12. Weight of wet sample plus tare gm 13. Weight of dry sample plus tare gm 14. Weight of Water in sample gm 15. Tare number and Weight No. # gm 16. Weight of dry soil gm 17. Moisture content 9.33 % 18. Dry density Kn/m 3

33 GRIAN SIZE ANALYSIS MECHANICAL Soil Classification Date of Test 13/10/1428 H Test No. 1 Test Location AL JUBAIL INDUSTRIAL Material Sand Layer Designation 6m depth Sample B Wt. of dry sample = 1000gm Sieve analysis and grain shape sieve No. #0.375 #4 #10 #20 #40 #60 #100 #200 Pan Diam.(mm) Wt. retained %retained %passing D60= 0.28 D30=0.17 D10=0.089 C u = D D = = 3.14 C z = D D D = = Soil classification AASHTO sys. : A-3 UNIFIED sys. : SP-SM

34 GRIAN SIZE ANALYSIS MECHANICAL Soil classification Date Of Test 13/10/1428 H Test No. 1 Test Location AL JUBAIL INDUSTRIAL Material Sand Layer Designation 6m depth sample E wt. of dry sample = 1000gm sieve analysis and grain shape sieve No. #0.375 #4 #10 #20 #40 #60 #100 #200 Pan Diam.(mm) Wt.retained %retained %passing D60= 0.29 D30=0.18 D10=0.09 C u = D D = = C z = D D D = = Siol classification AASHTO sys. : A-3 UNIFIEDsys.:SP-SM

35 SPECIFIC GRAVITY OF SOIL SOLID Date of Test 13/10/1428 H Test No. 1&2 Test Location AL JUBAIL INDUSTRIAL Material Sand Layer Designation 6m depth TEST NO. 0 C Vol. of flask at 20 Method of air removal W bws Wt.flsk+water+soil= 0 C Temperature W Wt. flask+ water = bw α Ws Wt. of dry soil = Ww = W + W W s bw Gs = αw s W w bws ml Vacuum 731.2gm gm gm ml Vacuum gm gm gm Avg. specific gravity of soil = 2.65

36 γ min γ max Determination Of Date of Test 13/10/1428 H Test No. 1 Test Location AL JUBAIL INDUSTRIAL Material Sand Layer Designation 6m depth 1. Weight of Empty Mold gm 2. Weight of mold + soil gm π 2 = cm 3. Area of mold 4 4. Height of mold 15.5 cm t 1 = t 0.95 cm, t avg. = = 1.02 cm 3 cm 5. Volume of mold *15.5= cm, t 3 = 1 cm, t 4 = 0.98 cm 6. t plate = 1.30 cm Weight of sand = (wt. of empty mold + sand) (empty mold) = = gm 9. γ Wt. ofsand vol. ofmold min = = = 1.614gm/ cm γ V V f f = V 0 A ( t 0 plate + t clear ) = ( ) = cm Wtofsand gm max = = = 1.89 / Vf cm 3 3

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38 APPENDIX B

39 FIELD RESULTS Max. and Min. Density : Sample # Min. Density kg/m 3 Max. Density kg/m Specific Gravity Specific gravity values ranged between and for more than 20 samples. Sieve Analysis Sieve Size mm % Passing Clay Lumps & Friable Particles 0.8 % Liquid Limit = Non Plastic Plastic Limit = Non Plastic Plasticity Index = 0

40 % Passing Grain Diam.(mm) Fig. Grain size distribution curve