HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION PROJECT OF FOUNDATION DESIGN INSTRUCTOR: DR. NGUYEN VAN CHUNG STUDENT: NGUYEN TRONG NHAN CLASS: 20149CLAS STUDENT ID: 20149103 HKI 2023-2024 TP HCM, 12/2022 Project of Foundation Design Instructor: Dr Nguyen Van Chung TABLE CONTENTS CHAPTER I: SOIL INVESTIGATION. Soil investigation formular and definition.23 CHAPTER II: DESIGN PAD FOOTING. Choose the depth of the foundation.
Determine size of foundation. Calculation of reinforcement.53 CHAPTER III: STRIP FOUNDATION DESIGN. Calculation strip foundation. Check size of foundation.
Check stability condition. Check the anti-slip forces condition. Check condition strength. Check settlement condition.66 Nguyen Trong Nhan - 20149103 2 Project of Foundation Design Instructor: Dr Nguyen Van Chung 8.
Check punching shear. Internal calculation of the strip foundation.Calculate the reinforcement. Calculate the reinforcement in foundation slab.74 CHAPTER IV: PILE FOUNDATION DESIGN. Calculation pile foundation.
Choose size of foundation. Determine the load capacity of the pile. Determine the number of pile and arrangement the pile. Check the bearing capacity of pile.
Check the load capacity of the pile. Check the stability and settlement of the pile foundation. Check the settlement condition of the foundation. Design pile cap.
Calculation reinforcement for pile cap. Check the capacity of the pile during transport and erection Nguyen Trong Nhan - 20149103 3 Project of Foundation Design Instructor: Dr Nguyen Van Chung. Calculation crane hook. 105 CHAPTER I: SOIL INVESTIGATION 1.
Soil investigation formular and definition: 1. Statistical theory: - Geological survey records for foundation design with a large number of boreholes and number of soil samples in a large soil layer. The problem is these soil layers we have to choose is the target to represent the background. - Initially, when drilling, sampling was based on the observation of color change, the degree of grain that we divided each layer of soil.
- According to TCVN 9362-2012, it is called a geotechnical layer when the set of values having its mechanical properties must have a sufficiently small coefficient of variation. Therefore, we must exclude the samples with data disparate with large mean values for a geological unit. - So geological statistics is a very important job in the calculation of the foundation. Division of geological units 1.
Coefficient of Variation We rely on coefficient of variation unary division: - The coefficient of variation v is determined by the formula: Nguyen Trong Nhan - 20149103 4 Project of Foundation Design Instructor: Dr Nguyen Van Chung - In there: Average value of a feature: Mean square deviation: The mean square deviation: When checking to eliminate gross errors for double criteria such as adhesion force (c) and internal friction angle � , the mean square deviation is determined as follows: With: is the eigenvalue of eigenvalues in the same soil layer. n: number of test samples of quantity A in the same soil layer. Rule for the exclusion of raw errors - In the sample set of a soil layer with coefficient of variation [], the opposite is achieved then we have to exclude data with large or small errors. - In which []: the largest coefficient of variation, look up Table 1 depending on each type of feature.
Table 1 Characteristic of the ground Coefficient of Variation [ν] Particle density 0.3 Cut resistance index 0.3 One-axis compressive strength 0.4 Nguyen Trong Nhan - 20149103 5 Project of Foundation Design Instructor: Dr Nguyen Van Chung - Check statistics, exclude too large or too small of A � values of according to the following formula | - A� | ≥ Vσcm. In which deviation is estimated: Note: When n take � �� = � Number of Value Value Number of Value Number of times standard standard times standard times determine number number determine number determine (n) (n) (V) (V) (n) (V) 6 2. Standard value of soil characteristics 1. Standard values of single indicators - Standard values of all single parameters (physical parameters such as humidity, bulk weight volume, plasticity index, viscosity,.
and mechanical parameters such as total Nguyen Trong Nhan - 20149103 6 Project of Foundation Design Instructor: Dr Nguyen Van Chung strain modulus, compressive strength, …) is the average of the individual test results Ā after, excluding gross errors. Standard value of dual indicators: - The standard values of the dual criteria of unit adhesive force (c) and internal friction angle () are made according to the method of least squares of the linear relationship of normal stress i and stress. the extreme contact i of the equivalent shear experiments: - The standard unit adhesive force ctc and the friction angle in the standard tc are determined by the following formula: - If the above formula can be calculated c tc < 0, then choose ctc = 0 and recalculate according to the formula: 1. Calculating soil characteristics 1.
Calculation value of single indicators - In order to improve the safety for the stability of the load-bearing foundation, some stability calculations of the foundation are carried out with the calculation characteristics. - The calculated value of single criteria is determined by the following formula: In there: Atc is the standard value of the features under consideration. The factor of safety on soil is determined by the formula: - The accuracy index is determined by the formula: In there: tα is the coefficient that depends on the confidence probability Dynamic coefficient is determined according to item 1.1 Nguyen Trong Nhan - 20149103 7 Project of Foundation Design Instructor: Dr Nguyen Van Chung When calculating the background by intensity (TTGH I), α = 0.95 When calculating the background according to strain (TTGH II), α = 0.85 - The minimum number of a certain criterion experiment with each engineering geological unit needs to be ensured is 6. - If within the scope of engineering geology unit there are less than 6 samples, the calculated values of their criteria are calculated according to the method of minimum average and average maximum: - The choice of calculation according to one of the two formulas depends on the criteria that increase the safety of the works.
Calculation value of double indicators - The calculated value of the double criteria is determined according to the following formula: In there: Atc is the standard value of the features under consideration. - For double criteria such as: stick force c and coefficient of friction tg. We have the formula: = tαν The coefficient of variation is determined according to the following formulas: and The mean square deviation is determined according to the following formula: When calculating the background by intensity (TTGH I), α = 0.95 When calculating the background according to strain (TTGH II), α = 0.85 Note: To find the standard and calculated values of c and , it is necessary to determine not less than 6 values of for each value of normal pressure. When finding the calculated value c, uses the total number of experiments to do n.
Degree of freedom (n-1) for Rn and γ Coefficient tα and c with accurate probability α Nguyen Trong Nhan - 20149103 8 Project of Foundation Design Instructor: Dr Nguyen Van Chung Degree of freedom (n-2) for c, φ 0.39 - The computed features according to TTGH I and TTGH II have values in the range: - Depending on the specific design case, we take the sign (+) or the sign (-) to ensure more safety. - When calculating the background according to the intensity and stability, we take the calculated characteristics according to TTGH I (in the larger range = 0. Nguyen Trong Nhan - 20149103 9 Project of Foundation Design Instructor: Dr Nguyen Van Chung - When calculating the background according to the deformation, we take the calculated characteristics according to TTGH II (in the range less than = 0. Geological statistics layer: Layer 1: - Sample number: 1 - Model number: HK-1 - Depth: 1.4 (m) - Soil properties: Clay loam, yellow brown – white gray, soft and hard plastic state Layer 2: - Sample number: 2 - Model number: HK-2, HK-3 - Depth: 2.5 (m) - Soil properties: Clay mixed Lateric gravel, yellow brown – pink brown-red brown, hard plastic state.
Layer 3: - Sample number: 10 - Model number: HK-4, HK-5, HK-6, HK-7, HK-8, HK-9, HK-10, HK-11, HK-12, HK-13.8 (m) - Soil properties: Clay loam, yellow brown -white gray-red brown, soft plastic state. Layer 4: - Sample number: 2 Nguyen Trong Nhan - 20149103 10 Project of Foundation Design Instructor: Dr Nguyen Van Chung - Model number: HK-14, HK-15 - Depth: 27.0 (m) - Soil properties: Heavy mixed clay, brown gray- brown black – yellow brown, soft plastic state. Single target statistics: 2. Layer 1: Natural weight N Model Drill hole Depth (m) Density () o number 1 HK1 HK1-1 1.01 - ) - Standard values: ) a) Determine the standard value: Empty factor by load class Model Empty factor e corresponding to the load class Drill P( No numbe Depth hole r (25-50) (50-100) (100-200) (200-400) HK 1 HK1-1 1.531 Targets c, τ = (kN/m2) Sample No.
Drill hole σ = 100 σ = 200 σ = 300 number 2 2 (kN/m ) (kN/m ) (kN/m2) 1 HK1 HK1-1 34.119 Using the LINEST function method in excel for statistics, we get: Nguyen Trong Nhan - 20149103 11 Project of Foundation Design Instructor: Dr Nguyen Van Chung The above sample set is selected Standard values 2. Layer 2 Natural weight N Model Drill hole Depth (m) Density () o number 1 HK1-2 3.21 - ) - Standard values: ) a) Check statistics: b) Determine the standard value: () Empty factor by load class Model Empty factor e corresponding to the load class Drill P( No numbe Depth hole r (25-50) (50-100) (100-200) (200-400) 1 HK HK1-2 3. Drill hole Sample τ = (kN/m2) Nguyen Trong Nhan - 20149103 12 Project of Foundation Design Instructor: Dr Nguyen Van Chung σ = 100 σ = 200 σ = 300 number (kN/m2) (kN/m2) (kN/m2) 1 HK1-2 0.359 Using the LINEST function method in excel for statistics, we get: The above sample set is selected Standard values 2. Layer 3A: Natural weight N Model Drill hole Depth (m) Density () o number 1 HK1-4 7.48 - ) - Standard values: ) a) Check statistics: Nguyen Trong Nhan - 20149103 13 Project of Foundation Design Instructor: Dr Nguyen Van Chung b) Determine the standard value: () Empty factor by load class Empty factor e corresponding to the load class Drill Model P( No Depth hole number (25-50) (50-100) (100-200) (200-400) 1 HK1-4 7.538 Targets c, Nguyen Trong Nhan - 20149103 14 Project of Foundation Design Instructor: Dr Nguyen Van Chung τ = (kN/m2) Sample No.
Drill hole σ = 100 σ = 200 σ = 300 number 2 2 (kN/m ) (kN/m ) (kN/m2) 1 HK1-4 46.742 Using the LINEST function method in excel for statistics, we get: The above sample set is selected Standard values 2. Layer 4 Natural weight No Model Drill hole Depth (m) Density (). number Nguyen Trong Nhan - 20149103 15 Project of Foundation Design Instructor: Dr Nguyen Van Chung 1 HK1-14 27.18 - ) - Standard values: ) a) Check statistics: => So all of the samples in layer 4 are selected b) Determine the standard value: () c) Determine the value according to limit state I: With limit state I then the confidence probability. Look up the table we get d) Determine the value according to limit state II: With the limit state II then the confidence probability.
Look up the table we get Empty factor by load class Nguyen Trong Nhan - 20149103 16 Project of Foundation Design Instructor: Dr Nguyen Van Chung Empty factor e corresponding to the load class Drill Model P( No Depth hole number (25-50) (50-100) (100-200) (200-400) 1 HK HK1-14 27.6775 Friction angle and stick force τ = (kN/m2) Sample No.