How to calculate the horizontal force of pile foundation

1. According to the empirical method for calculating the bearing capacity of single pile under vertical load, through the bearing mechanism of composite pile foundation with single pile and single pile cap under the action of pile cap, and based on the elastic theory, a formula for calculating the bearing capacity of composite pile foundation with low pile cap is proposed, The measured value is close to the calculated value. It is proved that the calculation method of bearing capacity of composite pile foundation established in this paper is feasible on the premise of considering the load sharing effect of pile cap and the increase of pile side friction and pile end resistance e to the effect of pile cap. It can be applied and referenced by engineering circles, and it can greatly save engineering funds with remarkable economic benefits

2.

According to 5.2.8 of pile foundation code, it is calculated as follows: quk = qsk + qpk

I Design data

1. Pile design parameters

pile forming process: Precast concrete pile

bearing capacity design parameter value: according to the building pile foundation specification table

orifice elevation 0.00 m

pile top elevation 0.50 m

pile body design diameter: D = 0.80 m

pile body length: l = 18.00 m

2. Geotechnical design parameters

layer number soil layer name layer thickness (m) layer bottom buried depth (m) rock Soil physical and mechanical index limit side resistance qsik (kPa) limit end resistance qpk (kPa)

1 fill 3.00 3.00 n = 5.00 17 -

2 red clay 3.00 6.00 α W = 0.70, IL = 0.50 26 -

3 red clay 3.009.00 α W = 0.70, IL = 0.50 29 -

4 red clay 3.00 12.00 α W = 0.70, IL = 0.50 32 -

5, red clay 3.00 15.00 α W = 0.70, IL = 0.50 33 -

6 red clay 3.00 18.00 α W = 0.70, IL = 0.50 34 2700

7, red clay 3.00 21.00 α W = 0.70, IL = 0.50 32 -

8, red clay 3.00 24.00 α W = 0.70, IL = 0.5032 -

3. Design basis

technical code for building pile foundation (JGJ 94-94), hereinafter referred to as pile foundation code

code for design of building foundation (GB 50007-2002), hereinafter referred to as foundation code

II Estimation of vertical compressive bearing capacity of single pile

1. Calculation parameter table

calculation thickness of soil layer Li (m) ultimate lateral resistance qsik (kPa) ultimate end resistance qpk (kPa)

13.00 17 0

23.00 26 0

33.00

53.00 33 0

62.50 34 2700

2; × 0.80 = 2.51 m

Ap =  × 802 / 4 = 0.50 M2

3. According to pile foundation code 5.2.8, the standard value of total ultimate lateral resistance of soil is calculated as follows:

qsk = u & # 61669; qsikli = 2.51 × ( seventeen × 3.00 + 26 × 3.00 + 29 × 3.00 + 32 × 3.00 + 33 × 3.00 + 34 × 50) = 1243 kn

the standard value of total ultimate end resistance is:

qpk = qpkap = 0.50 × 2700 = 1357 kn

the standard value of vertical compressive ultimate bearing capacity of single pile is:

quk = qsk + qpk = 1243 + 1357 = 2600 kn

the characteristic value Ra of vertical bearing capacity of single pile is calculated according to Article 7 of q.0.10 in Appendix Q of foundation code

RA = quk / 2 = 2600 / 2 = 1300 kn

extended data:

the rigidity of pile is small, The displacement of the top section of the pile is larger than that of the bottom, and the side friction at the top of the pile is usually larger; When the stiffness of the pile is large, the displacement of each section of the pile is close. Because the initial normal stress of the soil on the side of the lower part of the pile is large, the shear strength of the soil is also large, so that the side friction of the lower part of the pile is greater than that of the upper part of the pile

because the compression of the foundation soil at the bottom of the pile is completed graally, the load borne by the pile side friction will be transferred from the upper part of the pile to the lower part of the pile with time

in the process of pile foundation construction and after the completion of pile side soil properties, state will change in a certain range, affect the pile side friction, and often have time effect. Among the factors influencing the pile side friction, the type and property of soil are the main factors

When analyzing the bearing capacity of foundation piles, the influence of various factors on the size and distribution of pile side friction should be paid attention to. In the plastic state, pile driving in the viscous state will cause disturbance to the soil at the pile side, and the squeezing effect of pile driving will increase the pore water pressure in the soil around the pile, rece the shear strength of the soil, and rece the pile side friction

After a period of time, the excess pore water pressure graally dissipates, and the thixotropy of clay makes the shear strength around the pile not only recover, but also exceed its original strength, and the pile side friction is improved

When the pile is driven in the sand, the change of pile side friction is related to the initial density of sand. If there is dilatancy in the dense sand, the peak value of pile side friction will decrease

the size and distribution of pile side friction determine the change and value of pile axial force with depth, so it is important to master and understand the distribution law of pile side friction for studying and analyzing the working state of pile

because the relative displacement between pile and soil, the lateral stress in soil and the distribution and behavior of soil mass change with depth, it is more complex to accurately describe the distribution of pile side friction with physical and mechanical equations

3.

1、 The effect is different

1. Pile pressing: the soil is compacted to reinforce the foundation

Pile foundation detection: a method used to detect the vertical compressive bearing capacity of foundation piles

2. Different construction methods 1. Pile pressing: precast reinforced concrete pile and prestressed concrete pile. The precast pile is driven (pressed) into the soil by the impact energy of the pile hammer. The construction methods of sinking pile mainly include: hammer driving, vibration driving, water jetting, static pressing and drilling embedded pile

Pile foundation detection: the main methods of pile foundation detection include static load test, core drilling method, low strain method, high strain method, acoustic transmission method, etc

Pile pressing: as an important temporary structure of driven pile construction, driven pile guiding device should first ensure that the construction accuracy and efficiency of driven pile meet the requirements of design and construction, and also have the characteristics of simple structure, convenient disassembly and assembly, safe and reliable, economical and applicable. There is no clear specification for its structural design, and there are few systematic research results on its structural form

2. Pile foundation detection: in pile foundation detection, each detection means needs to be used together. Only by making use of their own characteristics and advantages and flexibly using various methods according to the actual situation, can we make a comprehensive and accurate evaluation of pile foundation

4. A lot of wallet is usually used to recharge and pay for goods, which is equivalent to the nature of Taobao Alipay.

5. 1. Decoration 2. Place the corresponding card

6. There are several known conditions for manual calculation of pile foundation:
1. Horizontal force and vertical force at pile top
2. Soil composition
3. Vertical bearing capacity of soil (rock) under pile
in the calculation, H (length of pile) and R (diameter of pile) are assumed to pass through several layers of soil within h length. Each layer of soil has friction resistance to the pile wall (please refer to the relevant code). The resultant force of the friction and the bearing capacity of the pile bottom can react to the vertical load of the pile (calculate how much vertical load the pile can bear)
as for the effect of horizontal load on pile top, in the bridge design code, there is a calculation method of pile foundation, called M method (foundation coefficient method), that is, every kind of soil has the ability to resist shear, and the combination of this ability to resist shear forms the resistance to horizontal force. By calculating the displacement of pile under horizontal load, the ability of pile to resist horizontal force in soil can be calculated. If the vertical load and horizontal load are calculated, then calculate the strength of the pile, and then install the section reinforcement

7. 1 The bearing capacity of single pile can be estimated by CPT
the interaction between probe and soil in CPT is similar to that between pile and soil, so the bearing capacity of single pile can be estimated by the specific penetration resistance (single bridge) measured by CPT or the cone tip resistance and side wall friction resistance in double bridge probe. However, the end resistance and friction in CPT can not be directly used as the end resistance and friction of actual single pile, but must be corrected because the working performance of CPT is different from that of actual single pile< (1) if there is no local experience, the standard value of vertical ultimate bearing capacity of precast concrete single pile can be calculated according to the following formula:
quk =
qsk + qpk = u ∑ qsik · Li+ α· PSK · AP
where: quk standard value of vertical ultimate bearing capacity of single pile
qsk standard value of total ultimate lateral resistance of single pile
qpk standard value of total ultimate end resistance of single pile
U -- circumference of pile body
qsik -- the standard value of ultimate lateral resistance of the i-layer soil around the pile estimated by the specific penetration resistance value of CPT
Li -- the thickness of the pile passing through the i-layer soil< br /> α—— Correction coefficient of pile end resistance< PSK is the standard value (average value) of CPT specific penetration resistance near the pile tip
AP -- pile tip area
(2)
when the standard value of vertical ultimate bearing capacity of single precast concrete pile is determined according to the static cone penetration test data of double bridge probe, for cohesive soil, silt and sand, if there is no local experience, it can be calculated according to the following formula:
quk = u ∑ Li β ifsi+ α Qcap
where FSI is the average lateral resistance of the probe in layer I soil
QC - probe resistance above and below the pile tip plane, the weighted average value of probe resistance according to the thickness of soil layer within 4D above the pile tip plane (D is the diameter or side length of the pile) is taken, and then the probe resistance within 1D below the pile tip plane is averaged< br /> α—— The correction coefficient of pile end resistance is 2 / 3 for cohesive soil and silt and 1 / 2 for saturated sand< br /> β I -- comprehensive correction coefficient of pile side resistance in the i-th layer< (2) to determine the bearing capacity of single pile by physical index method of soil
when determining the standard value of vertical ultimate bearing capacity of single pile according to the empirical relationship between physical index and bearing capacity parameters of soil, it should be calculated according to the following formula:
quk = qsk + qpk = u ∑ qsikli + qpkap
where: qsik - the standard value of ultimate lateral resistance of layer I soil at pile side, if there is no local empirical value, the specification can be consulted< When the pile center distance is less than or equal to 6 times of the pile diameter and the number of piles is more than 9 (including 9), the pile and soil can be taken as the hypothetical solid foundation. At this time, the pile abutment, pile and soil between piles form a whole and sink together under the upper load, This is pile group action. When checking the bearing capacity and settlement of this kind of pile foundation, it is considered as solid foundation
(1) checking calculation of bearing capacity of pile group
checking calculation of bearing capacity of pile group refers to checking whether the bearing capacity of foundation at the bottom of solid foundation (at the plane of pile end) meets the requirements. One of the common methods is to assume that the load is from the pile top of the outermost circle to the top of the pile φ 0 / 4 of the dip angle downward spread φ 0 is the average internal friction angle of each soil layer within the range of pile length), which should meet the following requirements:
under central load,
under eccentric load,
(2) when checking settlement of pile group,
when checking settlement of pile group, the pile group is also taken as the solid foundation, and the calculated pile foundation deformation value should meet the allowable value of building pile foundation deformation, If there is no local experience, the allowable value of building pile foundation deformation can be used according to the provisions in the table. For the allowable value of building pile foundation deformation not included in the table, it can be determined according to the adaptability of superstructure to pile foundation deformation and the requirements of use
the bottom dimension of solid foundation can be adjusted according to φ The range of 0 / 4 diffusion can also be taken according to the range of pile group at the pile end. The calculation results of the two methods are slightly different
the settlement calculation of pile group can be carried out according to the settlement calculation steps of shallow foundation, that is, the settlement calculation method described above. It can also be calculated by the equivalent action layer summation method.

8. How to calculate. In short, for expanding the foundation, how much is the load from above and how much is the bearing capacity of the foundation, calculate the width and length
then the cross-section is designed and checked. Just adjust it
how much force is transmitted from the top of the pile, how much bearing capacity of a single pile, and how many pieces are calculated. Arrange it, make a cushion cap, check it and adjust it. That's it
take a look at the textbooks, college textbooks. Or foundation design code. The specification can be downloaded from Zhong for free. If I don't have the electronic version, I won't send it to you. Excuse me
now we use software to calculate and get the results directly. Yes or no. The calculation process did not.

9. It's better not to use it. I'm next. It's all viruses. It almost broke the computer and it can't be used