STUDY ON THE SINGLE AND GROUP OF SOIL CEMENT PILE FOR HIGH RISE BUILDING

MINISTRY OF EDUCATION AND TRAINING DANANG UNIVERSITY DO HUU DAO STUDY ON THE SINGLE AND GROUP OF SOIL CEMENT PILE FOR HIGH RISE BUILDING MAJOR : MECHANICAL ENGINEERING CODE : 62.52.01.01 SUMMARY OF DOCTORAL DISSERTATION Da Nang – 2015 The doctoral dissertation has finished at Danang University of Technogogy - Da nang University Science Instructor: Prof.Dr Nguyen Truong Tien AProf Dr Phan Cao Tho Reviewer 1: Prof.Dr Trinh Minh Thu Reviewer 2: Prof.Dr Do Nhu Trang Reviewer 3: Dr Tran Dinh Quang Da nang - 2015 INTRODUTION Study Issues Soil cement pile is the product of the techniques of mixing cement in local soil – by deep mixing method, processing of forming the pile after the setting of cement The advantages of soil cement pile are reducing settlement for construction, reinforcing soft soil, increasing load bearing capacity for work foundation, highly mechanized construction, rapidly progressing construction, reducing costs by using local soil, reducing waste of soil and environment pollution For soil cement piles constructed in sandy soil, the unconfined compressive strength is from (3.010)MPa, so it can be applied as pile foundation bearing load construction of high rise buildings in the permitted conditions However, the stiffness of the SCP is small so that the conduct between the pile - soil, pile – soil - pile in the group will be different from the usual kind of concrete pile The main focuses, then, are the strength properties of materials sand-cement, load transfer mechanism, mobilization of side friction, tip resistance of single pile, the pile in the groups and determining group factor, and applying in the design stage for high-rise buildings This is the foundation of my dissertation: "Study on the single and group of soil cement piles for high-rise building." The purpose of the dissertation - Develop a database of properties of the material strength of soilcement piles by wet mixing method for some types of soil: sand, sandyclay, aims to create soil cement pile with high strength, bearing load for foundation construction - Study of the load transmission, the mobilization of side friction and tip resistance of single pile and group soil cement pile from full scale model test, as a basis for evaluation of soil cement pile for bearing load applications - Analyze of group soil cement pile by numerical model and building correlation about group factor for soil cement pile Study subjects Soil cement pile by wet mixing method, Japanese technology, constructing in sandy and sandy – clay, area of Quang Nam - Da Nang city Research Content - Overview of the mechanical properties of materials and the impact of the pile elements SCP, the problem of load bearing capacity of single pile and pile group, brief survey of regional geological characteristics of Da Nang - Quang Nam - Study on the strength characteristics of the material pile SCP by experiments in the laboratory and the field - Experiment on the full scale model test for single and group soil cement pile by static load compression with strain gages and analyze the results - Numerize simulation by Finite Element Method to verify the model test and practical projects, developing simulation to construct correlation group factor for group soil cement pile - Develop procedures calculations and computer program software SCPile to automate calculation and design for soil cement pile foundation Study Methodology - Exprimental methods in the laboratory and combine the field apply to the strength characteristics of the material soil cement piles - Experimental methods by full sacle model test with strain gages for single and group soil cement piles - Numerical simulation method by Plaxis 3D Foundation and development for various SCpile groups based on soil model Mohr - Coulomb Scope of Study - Soil cement pile by wet method, for sandy soils, sandy – clay on area of Quang Nam-Da Nang city, not use additives - The dissertation focuses on analyzing the soil cement pile bearing vertical load - Scope of applied: the high-rise building to level II (lower 19 floors) on sandy areas Danang and other area with similar geological New contributions of the dissertation - Developing a database of correlated about unconfined compressive strength and bending strength of material SCP for 04 soil types - Analyzing the load transmission and distribution side friction, tip resistance for single pile and pile group from full scale model test Determine the coefficient of side and tip resistance by formulations Meyerhof to apply calculation bearing capacity of single SCP - Analyzing the mobilizing resistance of piles in groups, determination of group factor and recommended calculating load capacity for SCP foundation by teamwork "Group" - Developing graphs and equations determining goup factor of the group SCP according to the number of pile with different distances from the 3D numerical simulation - Developing the procedures of calculation and the software program of SCPile automated calculation, design of SCP foundation and applied to one real projects The structure of the dissertation In addition to the introduction, table of contents, list of references, scientific published, drawings, tables, appendices, thesis consists of 130 pages is organized in five chapters: Chapter 1: Overview of the soil cement pile Chapter 2: Some results of experimental studies on the characteristics of the strength soil cement pile Chapter 3: Study the the single and group soil cement piles by full scale model test Chapter 4: Numerical simulation and construction of the correlation groups factor for soil cement pile Chapter 5: Application of soil cement piles for high rise building CHAPTER OVERVIEW OF SOIL CEMENT PILE 1.1 Introduction 1.1.1 Process of establishment and development of SCPile The soil cement pile originally is researched and applied in Sweden and Japan in the 1960s, and then now gained popularity in the worldwide market Two construction methods has usually been used are the wet and dry mixing methods Since 1980s, The soil cement pile (SCPile) in Vietnam has frequently been applied to the improvement of soft soil, they also have used for building 1.1.2 Applications of soil cement pile The applications of SCPile in Sweden, Japan and other countries has commonly been used to the improvement of soft ground In Vietnam, the research and application of SCPile in two principle directions: piles to the improvement of soft soil and piles bearing, including application of SCPile bearing in high buildings in geology condition is sand could increase efficiency, reduce costs 1.1.3 Deep mixing methods of soil cement pile In the deep mixing method, soft soil is stabilized in situ by two major techniques: the dry method of deep mixing is used for soft soil with high humidity from (60  200)% and the wet method of deep mixing is applied to soil has water content smaller Experiments in the thesis by the wet method 1.1.4 A number of domestic and foreign research on SCPile Includes two major groups: Group studies about strength characteristic of piles by laboratory experiments, field studies and other, studying mechanical bearing load of sigle and SCPile group Most studies have focused for the purpose use cement to improve soft clays, organic soils, soil swellings The thesis going to continue to develop on the basis of this approachs with SCPile application for bearing of the building foundation on sandy soil 1.2 Strength characteristics of SCPile For SCPile bearing for works, characteristics that have affect the significant important of which is: unconfined compressive strength, qu (in the room and field), bending strength qb, elastic modulus E50 1.3 Basic calculations for single and SCPile group 1.3.1 Load-bearing capacity of single pile Includes load bearing capacity follow the material of pile and the ground, with the methods of calculation of Broms (1984) [1], Japan [37], Jiehan (2011) [56] These methods are based on the application of the SCPile to improvement of soft clay ground Some calculations based on formulas from SPT testing results such as Meyerhof and Japan, however, the coefficients of the skin resistance and the tip resistance are inappropriate and should be determined from the results of experiments 1.3.2 Calculation of pile groups SCPile - Ultimate bearing capacity of SCPile group: usually be applied according to viewpoint of pile foundation work as style "Block" of Bergado by Equation (1.9) and (1:11), the method of Broms by Equation (1:12) Method of Bouassida and Porbaha by Equation (1:13) and (1:14) has more advance, but still the concept equivalent background For SCPile group, this position is not reasonable So, need to determine a suitable method for practical applications - The effect of pile groups: be assessed through the efficency pile groups The methods according to Feld's (Equation 1:15), Terzaghi and Peck (Equation 1:16), Convese-Labarre (Equation 1:17), Coduto (Equation 1:18) and Seyed & Bakeer (Equation 1:20) In this follow-Labarre Convese is applied more widely However these methods are applied to hard piles For SCPiles which have smaller stiffness and behavior between pile - soil, pile - soil - pile have more difference Thus, the effect of pile groups is need to research additionally and determination of the efficiency pile groups 1.4 Geological features in Da Nang - Quang Nam and application prospects SCPiles for high rise buildings The research and the survey’s results show that the geological characteristics of Da Nang city is sandy soil which is distributed over the surface with the thickness from 13m to 18m This sand is reasonable to use the solution of SCPile for high buildings to level II (19 floors), contributing to decrease costs Figure 1.15 A typical geological section of Danang city [4] 1.5 Some problems exist in study on SCPile for high rise buildings 1.5.1 Some problems exist Material: The study material for soil-cement pile concentrated for the purpose of handling the soft clay soil is not suitable for applications such as a SCPile solution for bearing load Bearing capacity of piles and pile groups: methods for calculating the bearing capacity of the pile and pile groups follow material and ground are based on shear strength of soft soil around piles and pile groups This calculation does not suitable with the opinion SCPile work as piles 1.5.2 The task of the dissertation This dissertation develops on the strength of SCPile material for specific types of soil which can be applied for constructing bearing piles Researching on the working process of single pile and SCPile group through full scale model and 3D simulation At the same time, establishing a calculation process to initially applied in the calculation, the practical design CHAPTER SOME RESEARCH RESULTS OF STRENGTH CHARACTERISTICS FOR SOIL CEMENT PILE’S MATERIAL 2.1 Introdution The working process of the SCPile as the transmission of SCPile, mobilizing resistance, pile group effects, horizontal bearing capacity which will depend on two properties: unconfined compressive strength qu and bending strength of pile qb Therefore, before analyzing the working of single pile and pile group is need to have the results of research on the characteristics and relative strength This chapter presents the results of laboratory experiments on the properties of the material strength of SCPile 2.2 The scope of sampling and testing of soil, cement Scope of soil sampling: The laboratory will focus for 04 soil groups include: group No.1: clayey sand soil, group No.2: fine-grained sand, group No.3: small-grained sand and group No.4: coarse-grained sand Grain size distribution 100 80 70 60 50 40 No1 30 No2 20 No3 10 Perecent finer by weight(%) 90 No4 0.001 0.01 0.1 Grain size (mm) 10 100 Figure 2.2 Grain size distribution of 04 soil types The laboratory experiments about properties of soil is examined through XRF machine to determine the amount of oxides in the soil Cement and water: The chemical testing of the two types of cement PCB30 and PCB40 were also analyzed Use clean water to mix the sample 2.3 Method of testing and calculation the result Soil ax=150kg/m3 ax=200kg/m3 qu, qb (7days) Cement ax=200kg/m3 qu, qb (14days) ax=300kg/m3 qu, qb (28days) ax=350kg/m3 qu, qb (56days) Correlation %qu, qb -ax-t qu, qb--t qu, qb - ax - t E50 - qu qu - qb Figure 2.4 The laboratory experiments programme and analysis The mixing, casting and curing samples and calculating the results by (TCVN9403: 2012)[20] Compression and bending samples on automatic that can produce chart of stress - strain by Trapezium software 2.4 Results of experimental studies 2.4.1 Results of compressive testing Some charts show of the relationship between qu-ax-t, E50 - qu - ax 12 1400 y = 124.84x R2 = 1.00 y = 1.08Ln(x) + 5.97 1200 10 1000 y = 1.18Ln(x) + 2.30 y = 1.05Ln(x) + 2.43 y = 1.07Ln(x) + 0.46 150kg/m3 E 50 (N/mm2) qu(N/mm2) y = 1.19Ln(x) + 3.45 y = 113.40x R2 = 0.99 800 TH1 600 y = 98.58x 400 200kg/m3 y = 0.67Ln(x) + 0.22 250kg/m3 300kg/m3 0 10 20 30 Curing time (days) 40 50 350kg/m3 60 Average Figure 2.16 Relationship qu-ax-t for fourth soil type TH2 R2 = 1.00 TH3 y = 90.66x y = 84.31x R = 0.83 R2 = 1.00 200 0 qu(N/mm2) TH4 TH5 10 12 Figure 2.20 Relationship E50 - qu - ax for fourth soil type 12 Single SCPile Model D600, l=7,5M Pile raft Concrete 35Mpa 0.00 # ST1: -1.5m Fine sand Layer 1: Fine sand depth : 2m Layer 2: Clay sand, depth: 2,0m # ST2: -3.5m -4.00 Layer 2: Clay sand, depth: 2,0m # ST2: -3.5m Stell tube D60 # ST3: -5.5m Medium sand Strain gages Layer: Medium sand, depth 5,5m Strain gages # ST4: -7.3m SCPile D600 # ST2: -3.5m # ST3: -5.5m Layer 3: Medium sand, depth 5,5m Strain gages # ST4: -7.3m SCPile D600 2200 Pile tip: -7.50 Pile tip: -7.50 Strain gages Telltale d=22mm Strain gages Telltale d=22mm TP2 S= 1,5D=1200mm 2250 TP3 Steel tube D60 d=1,2mm (A9) Steel tube D60 d=1,2mm (A9) TP6 TP7 Steel tube D60 d=1,2mm (A9) Pile tip: -7.50 Strain gages Telltale d=22mm 12 TP5 Steel tube D60 TP1 d=1,2mm (A9) 2200 TP4 50 22 200 Steel tube D60 d=1,2mm (A9) Layer 2: Clay sand, depth: 2,0m # ST4: -7.3m SCPile D600 Steel tube D60 d=1,2mm (A9) # ST1: -1.5m Stell tube D60 # ST3: -5.5m Mediunm sand Stell tube D60 Layer 1: Fine sand depth : 2m -4.00 -4.00 Layer 3: Medium sand, depth 5,5m +0.25 -2.00 Clay - sand -2.00 Clay - sand Clay-sand +0.25 700 # ST1: -1.5m Fine sand Layer 1: Fine sand depth : 2m -2.00 Medium sand Group 05 SCPiles Model D600, l=7,5M Pile raft Concrete 35Mpa 0.00 700 Pile head: +0.2 0.00 Fine sand Group 03 SCPiles Model D600, l=7,5M TP8 TP9 Strain gages Telltale d=22mm Steel tube D60 d=1,2mm (A9) TP10 Figure 3.8 Drawwing of full sacle load tets for sigle and group SCPile 3.3 Establish models and conduct experiments Some pictures constructing and loading full sacle model test Table 3.2 Design layout of test equipment for model No 01 02 03 04 05 Pile TP4 TP5 TP1 TP2 TP3 Test equipment ST(01), GKA9 (01)Telltale (01) GKA9 (01) Telltale (01), GKA9 (01) Strain gages (01), Telltale (01) GKA9 (01) Number 06 07 08 09 10 Pile TP6 TP7 TP8 TP9 TP10 Test equipment ST(01), Telltale (01) ST(01), Telltale (01) GKA9 (01) GKA9 (01) Telltale (01) SCPiles have diameter 600mm, length 7.5 m, qutk = 5,5MPa 13 3.4 Analysis of the experimental results 3.4.1 The basis of analysis transmission and ultimate bearing capacity 3.4.2 Analysis of single pile 3.4.2.1 Analysis transmission for single pile Load (kN) -0.5 200 400 600 Side friction (kPa) 800 1000 1200 -0.5 -1.5 -2.5 -2.5 Depth (m) Depth (m) -1.5 -3.5 20 40 60 80 -3.5 -4.5 -4.5 -5.5 -5.5 -6.5 -6.5 -7.5 -7.5 Figure 3.17 Load distribution on TP5 Figure 3.18 Graph distribution side friction of TP5 3.4.2.2 Analysis ultimate bearing capacity for single pile 0.04 Load P(kN) -5 0.035 200 400 600 800 1000 1200 0.025 -15 S/P Movement S(mm) y = 0.0007x + 0.0057 R2 = 0.9995 0.03 -10 0.02 y = 0.0007x + 0.005 -20 R2 = 0.9991 0.015 -25 -30 TP4 Davis sion Offset -35 -40 0.01 TP5 TP4 0.005 De Beer method Snip method Ave Sigle SCP -45 Figure 3.25 Detemination limit bearing capacity Qu of TP4 and TP5 TP5 0 10 20 30 40 50 S(mm) Figure 3.26 Detemination Qu from Chin Konder extraplation Skin resistance of the piles through the soil layer is evaluated via  factor by method of Bjerrum -Burland, and calculate inversely coefficient of skin resistance Cs follows Eslami and Fellenius from cone penetration test 14 Calculate inversely coefficient of skin resistance and tip resistance in the formula for calculating the bearing capacity for SCPile according Meyerhof (3.4), the coefficient K1, K2 clearly show a decrease in tip resistance and a increase the skin resistance of SC pile (3.4) Qu  K N a  K N tb As Table 3:17 K1 and K2 coefficients for the formula of Meyerhof Bearing factor Precast pile Bored pile Factor K1 (kPa) 400 120 Factor K2 (kPa) 2,0 1,0 SC pile 100 3,0 3.4.3 Analysis of pile groups 3.4.3.1 Analysis transmission and distribution skin friction of piles in group Load (kN) 200 400 600 Load (kN) 800 Load (kN) 1000 -0.5 200 400 600 800 1000 -0.5 -1.5 -1.5 -2.5 -2.5 -2.5 -3.5 Depth (m) -1.5 Depth (m) Depth (m) -0.5 -3.5 -4.5 -4.5 -5.5 -5.5 -5.5 -6.5 -6.5 -6.5 -7.5 -7.5 -7.5 Load distribution TP7-G2 200 400 600 800 1000 -3.5 -4.5 Load distribution TP3-G1 Load distribution TP8-G3 Chart sum mobilized side friction and tip resistance for the single pile and pile group Qf(kN) 150 300 450 600 750 -10 -20 -20 S(mm) -30 300 450 600 750 -30 -40 -60 150 S pile tip(mm) -10 -50 Qr(kN) 0 -40 TP5 TP3 TP7 TP8 Figure 3.46 Graph mobilized side friction -50 -60 TP5 TP3 TP7 TP8 Figure 3.47 Graph mobilized tip resistant 15 Below charts display distribution skin friction along the shaft pile under the load levels for the piles TP3, TP7, TP8: Side friction (kPa) 20 40 60 80 -0.5 -1.5 -1.5 -1.5 -2.5 -2.5 -2.5 40 60 80 20 40 60 80 -0.5 Depth (m) -3.5 20 -0.5 Depth (m) Depth (m) Side friction (kPa) Side friction (kPa) -3.5 -3.5 -4.5 -4.5 -4.5 -5.5 -5.5 -5.5 -6.5 -6.5 -6.5 -7.5 -7.5 -7.5 Distribution fi TP3-G1 Distribution fi TP7-G2 Distribution fi TP8-G2 Table 3.18 The unit skin resistance fs from experimental results (kPa) Depth 0-2,0m 2-4,0m 4,0-5,5m 5,5-7,5m TP5 62,12 26,79 53,25 57,75 TP3 62,02 25,79 51 54 TP7 63,62 24,44 41,25 50,25 TP8 62,99 26,39 49,50 51,00 Table 3.19 The skin resistance and tip resistance of piles (kN) Resistance Qf Qr TP5 638,17(0%) 582,68 (0%) TP3 625,5(-1,98%) 290,4(-45,1%) TP7 535,03(-16.16%) 304,97(-47,66%) TP8 611,52(-4,17) 228,48(-60,78%) 3.4.3.2 Analysis ultimate bearing capacity of pile 0.07 Load P(kN) 0 180 360 540 720 900 0.06 1080 -20 -30 -40 -50 -60 y = 0.0009x + 0.0208 Nhóm G2 0.05 S/P Movement S(mm) -10 TP4 TP5 G1 G2 Davission Of f set De Beer method Snip method Ave Single SCP Figure 3.54 Analysis Qu of piles tets y = 0.0008x + 0.0116 Nhóm G1 0.04 0.03 y = 0.0007x + 0.0057 Cọc đơn TP5 0.02 y = 0.0007x + 0.005 Cọc đơn TP4 0.01 0 10 20 30 40 50 60 S(mm) Figure 3.55 Analysis Qu by extrapolation 16 Table 3:21 Results of efficiency of pile groups from testing Efficiency of pile groups  determine from Qu follow methods Pile groups De Beer Snip Davission Group G1 (03 piles) 0,685 0,684 0,664 Group G2 (05 piles) 0,608 0,586 0,554 Chin 0,875 0,778 Method Davission is selected to calculate the efficiency of pile groups Table 3:22 Comparison groups factor from test result and other formulas Comparison efficiency of pile groups  with theoretical formulas Terzaghi ConveseCoduto, Sayed Pile/pilegroup Testing Feld’s & Peck Labarre 2001 Bakeer Cọc đơn 1,0 1,0 1,0 1,0 1,0 1,0 G1 (03 cọc) 0,87 0,75 0,69 0,595 0,796 0,664 G2 (05 cọc) 0,80 0,688 0,56 0,455 0,566 0,554 3.5 Propose bearing capacity calculation methods for SCPile group Calculate the bearing capacity of SCPile group by Terzaghi & Peck: Qug  n1 n2 Qu (3.5) N H Qf Qr B (6-9)Cu Failure surface Cu Cu M Soil cement pile H H Soil cement pile q L Figure 3.56 Method “Block” by Bergado, 1994 Figure 3.57 Method “Group” is proposed SCP 3.6 Conclusion of chapter Building a model experiments using test equipment axial deformation strain gauges, evaluate the mobilization of skin friction and tip resistance of single pile and pile group, determination of groups and proposed calculation scheme SCPiles with perspective pile group working as "group" 17 CHAPTER NUMERICAL SIMULATION AND ESTABLISH RELATIONSHIP ABOUT EFFICIENCY OF PILE FOR SCPILE 4.1 Purpose and method SCPile parameters: kE, D, L Pile raft size Soil parameters: kc, E Soil model Mohr - Coulonb Simulation Model test Simulation Model test project study for group factor Single SCP Group SCP Group SCP TP4 G1 G2 Simulation and analysis model test 05 project Group from to 25 SCP Rate: d/D=1, 1.5, 2, 3, 6, Compare with model test Compare with model test Analysis P-S correlation Determine group factor Simulation case Figure 4.2 Tree graph of case studies numerical simulation for SCPile a) b) Pile raft P Soil cement pile 12 III 15  II II 14 5x 13 Soil Soil II x x6 11 y Soil II-II x Soil cement pile D I-I Soil cement pile 3x  Figure 4.3 Axisymmetry element 3D z D Soil x 10 z y 4x  L I x L Soil cement pile P d Figure 4.4 Numerical simulation 3D for single and group SCPile 18 4.2 Numerical simulation for testing model Perform numerical simulation by Plaxis 3D Foundation software follow FEM for single pile, the G1 and G2 groups Simulation results for the quite reasonable results compare with the load test data from the models Load P(kN) Load P(kN) 200 400 600 800 1000 1200 200 400 600 800 1000 -20 -25 -30 -35 Thí nghiệm TN4 -40 FEM 3D TN4 -40 1000 -40 -50 -50 Thí nghiệm G2 -60 FEM-3D-G1 FEM-3D-G2 Daviss ion Line Davission Line -70 -70 Figure 4.9 Graph P-S group G1 Figure 4.7 Graph P-S single pile TP4 800 -30 -30 Thí nghiệm G1 -45 600 -20 -20 -60 Davission Line 400 Movement S(mm) -15 200 -10 -10 -10 Movement S(mm) Movement S(mm) Load P(kN) 0 -5 Figure 4.11 Graph P-S group G2 4.3 Numerical simulation of SCPile for practical projects 3D numerical simulation for single piles and groups of 02, 04, 05 and 07 SCPiles with the different distance of 05 practical projects in Da Nang and Quang Nam includes: Da Nang KIA Showroom, Office Complex FPT, low-income apartments in neighborhoods An Trung 2, Hospital of Dien Ban and Tran Thi Ly bridge Comparison of P-S curve results for closely with static compressive testing 4.4 Simulation of construction correlation coefficient pile group SCP Simulation of the 06 cases pile group 4, 6, 9, 16, 20 and 25 piles at a distance d/D=(1, 1.5, 2, 3, 6, 8) Determining efficiency of pile groups, build relationship of their about for SCPile groups 1 0.9 0.9 y = 1.07x -0.07 0.8 0.7 Group factor  Group factor  0.8 Nhóm cọc 0.6 Nhóm cọc 0.5 Nhóm cọc Nhóm 16 cọc 0.4 0.6 y = 1.06x -0.19 0.5 y = 1.01x -0.26 0.4 y = 0.92x -0.31 0.3 d=1D d=1.5D d=2D d=3D d=6D d=8D Power (d=1D) 0.2 Nhóm 20 cọc 0.3 y = 1.07x -0.11 0.7 0.1 Nhóm 25 cọc 0.2 d/D Figure 4.31 Group factor by d/D of other pile groups y = 0.76x -0.34 11 13 15 17 19 21 23 25 27 29 Number of SCPile Figure 4.32 The graph determination group factor with number of pile in group 19 According to chart (4.31) allows determination of efficiency of pile groups for the group from (425) piles with central pile spacing d=(1,08,0)D Charts (4.32) show determination of pile groups  relative with n number of piles in the group and the relative corresponding equation 4.5 Conclusion of Chapter Using Plaxis 3D Foundation software by finite element method and models Mohr-Coulomb soil materials simulation model for the experimental results of 05 practical projects On the basis of a reasonable balance between simulation and experimental results, conducted simulations for different cases of pile groups in number and different distances, building maps and math equations determination for calculation of the SCPile bearing capacity CHAPTER RESEARCH APPLICATION OF SOIL CEMENT PILE FOR THE HIGH RISE BUILDING 5.1 Introduction The content of this chapter is to establish a sequence of SCPile foundation design calculations condition has not standard At the same time, conduct build SCPile software for calculation, design and application SCPiles for a ptactical project 5.2 Construction calculations sequence pile SCPile On the basis of Pile foundation Design standards TCVN 205: 1998, Standard TCVN 9403: 2012, the results of research in the country, the world and the results of the thesis The authors constructed sequence calculation, design consists of 16 steps for pile SCPile, SCPile test under the limit state based on assumptions and mechanical diagrams 5.3 Construction program design calculations SCPile Sitemap general algorithm of a computer program is based on SCPile order calculations in Section 5.2 as follows: 20 Input Checked axila load: Pmax, Pmin Input data: Soil parameter, SPT, load, pile and pile raft dimension, material parameter of concrete and steel) Calculation: soil, foundation, SCPile Calculation pile bearing capacity, grout Checked the block foundation convention Checked soil bearing capacity, settlement Checked soft soil layer, time settlement Checked horizontal load: H n, [H] Group factor, pile group bearing capacity Calculation, dsign pile raft Calculation, design steel for pile raft Output Exel table, design data Output The programming language used to write programs calculate the SCPile soil cement pile is Visual Basic.net (VB.net) Software for calculations, tests and import, export from Excel Tính toán kết Calculation menu Formular Drawing result Figure 5.3 The interface of the program SCPile - Part calculated 21 5.4 Application of design calculations at building FPT Complex Application of design calculations at FPT Complex Project with more 1200 piles have D800mm diameter piles, length L=10m Pile layout distance between the central piles is d=1,5D=1.2m 1400 20 20 12 00 26 00 3000 60 8000 800 5200 20 3800 00 2400 14 3800 00 00 24 48 00 00 12 00 50 24 48 00 00 12 28 00 48 12 240 1600 40016 0040 48 00 80 40 B1 A1 00 12 24 00 4802 240 400 2400 7650 4800 2850 B2 4800 400 800 400 2000 12N 6000 12 2600 2600 6800 3200 3600 6000 6000 3600 0200 120 2400 240 0120 120 00 6800 32 00 68 3600 00 24 2400 24 12 00 00 1200 00 7650 4800 320 BH3 4800 12 50 28 50 50 76 50 48 28 28 50 60 1200 12 00 00 600 36 00 30 00 00 66 36 48 00 00 00 60 48 00 65 00 50 B3 00 72 00 60 60 72 00 00 24 00 28 50 50 28 28 00 65 24 76 520 D5 48 00 A2 200 900 300 48000 900 50 00 12 00 24 00 48 A3 28 1500 3200 240 48000 1200 28 80 410 12 00 00 24 00 00 48 A4 15 00 1200 65 00 00 50 48 76 600 240 2400 410 50 48 40 00 00 0012 12 00 24 48 00 4800 D4 00 BH4 00 76 00 50 48 24 50 76 48 48 0040 016 600 5200 2400 4800 12 00 B4 00 6000 120 60 02400 1200 480 00 240 790 360 24 48 00 00 12 B5 48 53 4800 24 48 00 8996 C 00 80 00 400 16 00 40 24 16 48 00 146 4800 8040 0 20 400 20 60 1950 12N 20 240 160 400 2400 16 00400 400 10800 48 BH7 48 00 600 00 00 00 12 00 00 48 C1 00 00 16 60 20 48 00 00 600 4000 4800 16 36 00 00 1600 4800 4800 24 00 3600 80 00 36 00 60 24 68 BH1 600 4800 00 360 7400 24 50 00 2600 00 00 72 48 00 28 600 3600 2400 600 00 600 32 60 3600 2400 600 36 60 36 00 1200 12 2400 00 BH6 0 38 80 40 40 3000 A5 A6 B Figure 5.6 Layout design soil cement pile of building FPT Complex 5.5 Evaluate technical and economic efficiency Compare the cost of SCPile with common types of piles for 06 projects in the area of Da Nang as Figure (5.13) 100 Percent % C2 60 6040 60 00 30 0 80 60 80 36 24 00 00 00 00 00 12 00 0 00 60 00 66 60 00 00 0 60 24 00 60 60 24 00 60 20 36 24 60 00 24 36 24 00 00 60 00 00 00 30 36 0 668 00 6000 60 00 14 30 2600 24 32 00 20 16 00 60 36 24 00 00 60 6600 3600 80 60 40 20 Bored pile D800 Spun pile D500 Case project Conc pile 350*350 SCPile D800 Figure 5.13 Compare by % the pile cots of project in Danang 5.6 The results of Chapter establish a sequence of SCPile foundation design calculations condition has not standard From there it established a general algorithm and detail algorithm, program development and application SCPile for a real project 22 CONCLUSIONS - RECOMMENDATIONS The conclusions The results of the "Study on single and groups of soil cement pile for high rise buildings", are showed as follow: - From the results of experimental studies in laboratory about strength characteristics of the SCPile material for 04 types of feature soils s of the area Da Nang - Quang Nam, with amount of cement changes (150350)kg/m3 of natural soil, establish relationships, including: the strength development qu and qb over time as a function logarit: clayey sand soil (group 1) qu=0,52Ln(t)-0,13 qb=0,25Ln(t)-0,18 fine - grained sand (group 2) qu=0,66Ln(t)+0,37 qb=0,33Ln(t)-0,15 small-grained sand(group 3) qu=0,75Ln(t)+2,03 qb=0,39Ln(t)+0,8 coarse-grained sand (group 4) qu=1,05Ln(t)+2,43 qb=0,45Ln(t)+1,12 The relationship between elastic modulus E50 and unconfined compressive strength qu about: E50 = (74,0133,3) qu; The relationship between bending strength qu and qb approximately: qb = (0,290,65)qu; relative strength in the laboratory qul and field strength quf between quf = (0,621,5)qul - Establish the relationship between the amount of cement ax and compressive strength qu for 04 soil types in the table below: clayey sand soil (No1) qu=1,08Ln(ax)-3,79 fine - grained sand (No2) qu=2,13Ln(ax)-8,9 small-grained sand(No3) qu=5,13Ln(ax)-23,22 coarse-grained sand (No4) qu=8,36Ln(ax)-39,44 a x  54,5q u2.0 a x  71,84q 1u.21 a x  67,04q u0.83 a x  72 ,14 q u0 68 - To assess the impact of grain size distribution and amount of SiO2 in soil, the amount of CaO of cement to the strength properties of the SCPile material In particular, the influence of grain size distribution, the thesis proposed factor Pd=(d>0.25mm)/(d>0.1mm) for the soil to determine qu relatively with the different amount of cement - From the experimental results and the full scale model analysis showed positive displacement due to mobilization of shaft friction on the pile SCPile (2022) mm relative with 3.5 percent of single pile diameter 23 and displacement from (3035) mm relative with 5.0 percent of single pile diameter for pile groups, larger than the notion mobilize shaft friction of hard piles about 8mm - From the experimental model of authors have determined the value of the coefficient of resistance  (according to the method ) by 0.53 in sandy clay soil and  = (0,690,77) in sandy soil, this result is consistent with the calculation of cone penetration testing of Eslami and Fellenius At the same time determine the bearing capacity factor applied to the pile SCPile based on the formula of Meyerhof (1976) to calculate the bearing capacity of the pile with the coefficients K1 and K2 = 100kPa = 2,5kPa - Analysis of the impact of the pile group showed significant declining shaft friction by effects of pile groups from 1.98% group (group piles) to 4.17% (group piles) while reducing shaft friction of middle pile to 16.16% At the same time raising the tip resistance of the middle pile higher than edge piles to 31.6% due to the formation of surface soil wedge tip pile group - Results of determination of pile groups for efficiency of pile groups  = 0.664 for group G1 (03 piles) and  = 0.554 for group G2 (05 piles), this result is quite closely with the method of Convese Labarre and the gap from 1.4% to 4.3% Suggest calculate the load capacity of SCPile groups in sandy soil by perspective as "Group" by formula of Terzaghi and Peck, results is higher (1,892,17) times than the opinion of pile groups as "block" also Bergado proposed calculation of weak ground - Results of numerical simulation used Plaxis 3D Foundation software and Mohr-Coulomb soil model for SCPile single piles and pile groups for 06 practical project show results is quite reasonable with experiments results On the basis of a reasonable balance between simulation and 24 experimental results, conducted simulations for different cases of pile groups in number and different distances, building maps and math equations determination for calculation of the SCPile bearing capacity d/D  d/D  d/D=1   0,72n 0 , 32 d/D=3,0   1,06n 0,19 d/D=1,5   0,92 n 0 ,31   1,01n 0, 26 d/D=6,0 d/D=8,0   1,07n 0 ,11 d/D=2,0   1,07n 0,07 - On the basis of Pile foundation Design standards TCVN 205: 1998, Standard TCVN 9403:2012, the results of research in the country, the world and the results of the thesis The authors constructed sequence calculation, design consists of 16 steps for SCPile, SCPile test under the limit state based on assumptions and mechanical diagrams To propose the scope of application subject: The subject aims is to use SCPile has high bearing capacity in the sandy soil, clayey sandy soil The applications for buildings will depend on the specific conditions of the ground conditions, vertical load, horizontal load and calculated parameters specific requirements to ensure the economic-technical Further research directions Further study of the dissertation can be developed as followed: - Researching on the effects of sea water enviroment to SCPile material strength and the declining of strength for SCPile over time - Researching on single piles and pile groups tolerating by horizontal loads - Completing the process of cacualtion and design in order to establish a primary standards in design calculations of SCPile foundation LIST OF PUBLISHED WORKS Scientific papers: Do Huu Dao (2011), Study the reasonable pile foundation for construction has average load in Da nang city, Science and Engineering Journal – Danang University, ISSN 1859-1531, Số: 7[48]/2011, page: 1-9 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien (2012), Study on the strength characteristics of soil cement pile material in sand – clay soil of Dien Ban - Quang Nam Area, Vietnam Geotechnical Journal, Vol 3-2012, ISSN-0868-279X, page: 28-34 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien (2012), Study on the correlation unconfined compressive qu and bending strength qb of soil cement pile The Vietnamese Mechanical Congress No 9, ISBN: 978-604-911-437-3, page: 31-38 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien (2014), Study on the the strength characteristics of soil cement pile for soil condition in Da Nang – Quang Nam, Vietnam Geotechnical Journal – ISSN - 0868 - 279X, Vol.1-2014, page: 24-34 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien (2014), Determining resistant factor of soil cement pile by full scale model axial load test with strain gages, T Vietnam Geotechnical Journal ISSN-0868-279X, Vol 2-2014, page: 24-34 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien (2011), Efficient use of soil-cement pile for high-rise buildings in Da Nang city, Vietnam and some issues to be studied, ISBN 978-604-82-000-8, Pages: 451-460 Do Huu Dao (2012), Laboratory and field load testing to study the characteristics of intensity and axial bearing capacity of soil cement pile/column in the coastal middle of Viet Nam (Supported by Nafosted), The Seven Asian Young Geotechnical Engineers Conference Tokushima – JaPan, ISBN 978-4-88644-819-4, Pages: 281-288 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien (2013), Experimental study on the strength characteristics of sand-cement pile Proceeding The first international conference Thu Dau Mot University - Foundation and Soft Ground Engineering ConferenceICTMU 2013, No: ISBN 978-604-82-0017-6, Pages: 291-301 Do Huu Dao, Nguyen Minh Hai (2013), High-rise building foundation on floating soil-cement columns (Supported by NafostedDU), The 5th International Young Geotechnical Engineering Conference - 5iYGEC’13 – Paris, No: ISBN 978-1-61499-296-7, Pages: 81-85 10 Do Huu Dao, Phan Cao Tho, Nguyen Truong Tien, Vu Ngoc Trung, Tran Bui Quoc An (2013), Application soil cement pile by Japanese technology in GPRS system for high road embankment of new Tran Thi Ly bridge-Danang city, Proceeding 40 Years of Cooperation between Vietnam and Japan in Construction, No: ISBN: 978-604-820053-4, Pages: 91-113 Scientific works: Do Huu Dao (Leader) – Nguyen Thu Ha – Pham Van Ngoc (2011), Study the reasonable pile foundation for construction has average load in Da nang city, Scientific work Danang University, No: Đ2011-02-20 Do Huu Dao (Leader) - Nguyen Van Quyen - Vo Hoang Tri (2012), Study the effect of cement content to the unconfined compressive strength to the soil cement pile material in the laboratory, Scientific work Danang University, No: Đ2012-02-25 [...]... number and different distances, building maps and math equations determination for calculation of the SCPile bearing capacity CHAPTER 5 RESEARCH APPLICATION OF SOIL CEMENT PILE FOR THE HIGH RISE BUILDING 5.1 Introduction The content of this chapter is to establish a sequence of SCPile foundation design calculations condition has not standard At the same time, conduct build SCPile software for calculation,... of the laboratory experiments qul 11 CHAPTER 3 STUDY ON WORKING OF SINGLE AND GROUPS OF SCPILE BY FULL SCALE MODEL EXPERIMENT 3.1 Introdution The purpose of the model construction: The construction of full scale model is to find about the movement of stress - strain, the transmission mechanism, mobilization of skinl friction, resistance in the top of single pile and pile group (SCPile) Based on the. .. calculation, design and application SCPiles for a ptactical project 5.2 Construction calculations sequence pile SCPile On the basis of Pile foundation Design standards TCVN 205: 1998, Standard TCVN 9403: 2012, the results of research in the country, the world and the results of the thesis The authors constructed sequence calculation, design consists of 16 steps for pile SCPile, SCPile test under the limit state... CONCLUSIONS - RECOMMENDATIONS 1 The conclusions The results of the "Study on single and groups of soil cement pile for high rise buildings", are showed as follow: - From the results of experimental studies in laboratory about strength characteristics of the SCPile material for 04 types of feature soils s of the area Da Nang - Quang Nam, with amount of cement changes (150350)kg/m3 of natural soil, establish... raising the tip resistance of the middle pile higher than edge piles to 31.6% due to the formation of surface soil wedge tip pile group - Results of determination of pile groups for efficiency of pile groups  = 0.664 for group G1 (03 piles) and  = 0.554 for group G2 (05 piles), this result is quite closely with the method of Convese Labarre and the gap from 1.4% to 4.3% Suggest calculate the load... applied to the pile SCPile based on the formula of Meyerhof (1976) to calculate the bearing capacity of the pile with the coefficients K1 and K2 = 100kPa = 2,5kPa - Analysis of the impact of the pile group showed significant declining shaft friction by effects of pile groups from 1.98% group (group 3 piles) to 4.17% (group 5 piles) while reducing shaft friction of middle pile to 16.16% At the same time... SCPile has high bearing capacity in the sandy soil, clayey sandy soil The applications for buildings will depend on the specific conditions of the ground conditions, vertical load, horizontal load and calculated parameters specific requirements to ensure the economic-technical 3 Further research directions Further study of the dissertation can be developed as followed: - Researching on the effects of. .. 1,07n 0,07 - On the basis of Pile foundation Design standards TCVN 205: 1998, Standard TCVN 9403:2012, the results of research in the country, the world and the results of the thesis The authors constructed sequence calculation, design consists of 16 steps for SCPile, SCPile test under the limit state based on assumptions and mechanical diagrams 2 To propose the scope of application subject: The subject... number of piles in the group and the relative corresponding equation 4.5 Conclusion of Chapter 4 Using Plaxis 3D Foundation software by finite element method and models Mohr-Coulomb soil materials simulation model for the experimental results of 05 practical projects On the basis of a reasonable balance between simulation and experimental results, conducted simulations for different cases of pile groups... calculate the load capacity of SCPile groups in sandy soil by perspective as "Group" by formula of Terzaghi and Peck, results is higher (1,892,17) times than the opinion of pile groups as "block" also Bergado proposed calculation of weak ground - Results of numerical simulation used Plaxis 3D Foundation software and Mohr-Coulomb soil model for SCPile single piles and pile groups for 06 practical project