Method for calculating single-pile vertical bearing capacity increment and optimizing pile length through hammering tubular pile squeezing effect

Abstract

According to the method for calculating the single-pile vertical bearing capacity increment and optimizing the pile length through the hammering tubular pile soil squeezing effect, sampling or in-situ testing is conducted on the pile side and the pile end after hammering tubular pile construction, and different soil body parameters are selected according to the soil layer property to reflect the state change after soil body vibration compaction; according to the method, the numerical values of the pile side friction resistance and the pile end resistance after vibration compaction are obtained, the vertical bearing capacity of the single pile after improvement is calculated, and finally, the pile length is optimized and designed through the standard value increment of the vertical ultimate bearing capacity of the single pile under the condition that the surrounding soil layer is not greatly changed. According to the method, the influence of vibration compaction on soil reinforcement is considered from engineering practice, the designed pile length can be reduced through calculation, and the construction cost is optimized.

Description

Technical Field

[0001] This invention relates to the field of pipe pile construction, specifically to a method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length through the soil squeezing effect of hammer-driven pipe piles. Background Technology

[0002] During the construction of driven pipe piles, it is common to encounter situations where the total number of hammer blows increases and the final penetration depth decreases, making it difficult to drive the piles into the ground. This can also easily lead to damage to the pile head or pile body during subsequent hammer blows. The reason for this is that driving pipe piles into undisturbed soil causes vibration compaction, altering the soil's state. This primarily affects the liquidity index of cohesive soil, the void ratio of silt, and the compaction of sand and gravel (it also has some effect on fill, silt, and silty soil, but this effect is negligible). After vibration compaction, the soil's state changes, increasing the side friction between the soil and the pile. The pile tip resistance also increases after the soil compaction. If the increased side friction and pile tip resistance after vibration compaction are taken into account, the designed pile length can be reduced. This reduces project costs, saves construction time, and reduces the total number of hammer blows, preventing damage to the hammer head or pile body. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for calculating the increase in vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles. This method involves taking soil samples from the site after hammering construction. Depending on the site conditions, the liquidity index of cohesive soil can be determined through a combined indoor liquid and plastic limit test; the void ratio of silt can be indirectly determined through indoor density and water content tests; and the compaction of sand and gravel can be determined through standard penetration tests in the field. This reflects the change in soil state after vibration compaction. Then, according to Tables 5.3.5-1 and 5.3.5-2 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", the increased values ​​of side friction and end resistance after the change in soil state can be found. This allows for the determination of the standard value of the vertical bearing capacity of the single pile after vibration compaction, enabling optimization of pile length, reducing project costs, and optimizing the construction period.

[0004] The technical solution provided by this invention is a method for calculating the increment of vertical bearing capacity of a single pile and optimizing the pile length through the soil displacement effect of hammer-driven pipe piles, comprising the following steps:

[0005] (1) After the construction of the pipe piles near a certain hammer-driven pipe pile is completed, after the construction of this pipe pile, according to the geological survey data and different soil layers, take corresponding measurement methods to sample the soil layer after vibration compaction or conduct standard penetration test to obtain the side friction resistance and pile end resistance after different soil layer states are changed.

[0006] (2) Calculate the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction using the side friction and pile end resistance obtained in step (1). :

[0007] =

[0008] in: The circumference of the pile body; For the first pile Soil layer thickness; The area at the pile tip; This is the standard value of the ultimate side friction resistance. This is the standard value of the extreme end resistance;

[0009] (3) Standard value of vertical ultimate bearing capacity of a single pile before vibration compaction Standard value of vertical ultimate bearing capacity of a single pile after vibration compaction Calculate the increment of the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction. :

[0010] = - =

[0011] in: = , The original soil layer Standard value of ultimate side friction resistance of the layer; This is the standard value of the ultimate end resistance at the pile tip in the original soil layer.

[0012] Furthermore, in step (3), the increment of the standard value of the vertical ultimate bearing capacity of a single pile is used. When the surrounding soil layers remain relatively unchanged, optimize the design pile length. ,

[0013] Standard value of vertical ultimate bearing capacity of a single pile before vibratory compaction :

[0014] =

[0015] Obtained: Original pile length - ) /

[0016] Standard value of vertical ultimate bearing capacity of a single pile after vibration compaction :

[0017] =

[0018] Result: Post-processed pile length - ) /

[0019] make: = It is easy to know:

[0020] =

[0021] = - ) / - - ) / .

[0022] Furthermore, in step (1), if the soil layer through which the pile body passes is fill, silt or silty soil, the soil compaction and vibration have little impact on the soil layer state, and the effect of increased side friction is not considered.

[0023] Furthermore, in step (1), if the soil layer through which the pile penetrates is cohesive soil, the effect of soil compaction and vibration on the soil state manifests as a change in the liquidity index. The water content is determined by taking samples of the vibratory compacted clay layer and conducting a combined liquid and plastic limit test. Liquid limit water content Plastic limit moisture content The liquid limit index after vibration compaction was calculated using a formula. ,in accordance with The standard value of the ultimate side friction resistance of the cohesive soil layer after vibration compaction was obtained by interpolation. Standard value of ultimate end resistance of pile .

[0024] Furthermore, in step (1), if the pile body passes through silty soil, the effect of soil compaction and vibration on the soil state manifests as a change in void ratio. The moisture content is determined by sampling the silty soil layer after vibration compaction and conducting laboratory tests. Soil density The porosity after vibration compaction is calculated using a formula. ,in accordance with The standard value of the ultimate side friction resistance of the silt layer after vibration compaction was obtained by interpolation. Standard value of ultimate end resistance of pile .

[0025] Furthermore, in step (1), if the pile penetrates a soil layer consisting of sand and gravel, the effect of soil compaction and vibration on the soil state is manifested as a change in the standard penetration test (SPT) blow count. By conducting SPT tests on the sand and gravel after vibration compaction, the blow count after vibration compaction can be directly obtained. ,in accordance with The standard values ​​of the ultimate side friction resistance of the vibratory compacted sand and gravel were obtained by interpolation. Standard value of ultimate end resistance of pile .

[0026] Furthermore, in step (1), when sampling or conducting standard penetration tests on the soil layer after vibration compaction, the sampling or standard penetration test should be conducted close to the perimeter of the last pipe pile. The distance between the sampling point or the standard penetration test point on the plane and the pile edge should not be greater than 0.3m, and there should be no less than 3 sampling points or standard penetration test points.

[0027] Furthermore, in step (1), when sampling or conducting standard penetration tests on the vibratory compacted soil layer, samples are taken uniformly in a certain soil layer depth direction or standard penetration tests are conducted.

[0028] Furthermore, in step (1), when sampling or conducting standard penetration tests on the soil layer after vibration compaction, the sampling or standard penetration test range for the bearing layer at the pile tip is from the pile bottom to 0.5m below the pile bottom surface.

[0029] Furthermore, in step (1), samples are taken from the vibratory compacted soil layer or a standard penetration test is performed, and the average value obtained is taken as the standard value of the ultimate side friction resistance. and the standard value of the extreme end resistance .

[0030] Furthermore, the method in step (1) is applicable to other pile foundations where soil squeezing effects exist.

[0031] This invention measures the changes in soil state after vibration compaction by taking soil samples from the field after construction and combining laboratory tests or field standard penetration tests. This indirectly reflects the increase in ultimate side friction and ultimate end resistance, thereby determining the increase in the vertical bearing capacity of a single pile caused by vibration compaction during hammer-driven pipe pile construction.

[0032] The calculation method provided by this invention is based on engineering practice. It combines on-site sampling with indoor tests or on-site standard penetration tests to quantitatively calculate the increase in the vertical ultimate bearing capacity of a single pile after vibration compaction during hammer-driven pipe pile construction. This method can optimize the design pile length, shorten the hammer-driven construction time, reduce pile bursting, save project costs, and the calculation results are relatively accurate. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a soil layer sampling or standard penetration test point in the embodiment. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments. Figure 1The accompanying drawings are simplified versions of the embodiments and are intended only to clearly and concisely illustrate the purpose of the embodiments of the present invention. The technical solutions shown in the drawings below are specific solutions of the embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] The embodiment provides a method for calculating the increment of vertical bearing capacity of a single pile and optimizing the pile length based on the soil displacement effect of hammer-driven pipe piles, which specifically includes the following steps:

[0036] S1. After the construction of surrounding pipe piles near a certain driven pipe pile is completed, based on geological survey data and different soil layers, appropriate measurement methods are used to obtain the side friction and pile end resistance after different soil layer conditions:

[0037] S1.1 If the pile penetrates fill, silt, or silty soil, the soil compaction and vibration have little impact on the soil condition, so the increase in side friction can be disregarded. For fill or silt, vibration compaction has no effect on bearing capacity.

[0038] S1.2 If the pile penetrates a cohesive soil layer, the effects of soil compaction and vibration on the soil state are manifested as changes in the liquidity index. The water content is determined by taking samples of the vibratory compacted clay layer and conducting a combined liquid and plastic limit test. Liquid limit water content Plastic limit moisture content The liquid limit index after vibration compaction was calculated using a formula. According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on The standard value of the ultimate side friction resistance of the cohesive soil layer after vibration compaction can be obtained by interpolation. .

[0039] S1.3 If the pile penetrates silty soil, the effects of soil compaction and vibration on the soil condition manifest as changes in the void ratio. The moisture content of the silty soil layer after vibration compaction is determined through laboratory sampling and testing. Soil density The void ratio after vibration compaction can be calculated using a formula. According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on The standard value of the ultimate side friction resistance of the silt layer after vibration compaction can be obtained by interpolation. .

[0040] S1.4 If the pile penetrates a soil layer consisting of sand and gravel, the effects of soil compaction and vibration on the soil condition are manifested as changes in the standard penetration test (SPT) blow count. The blow count after vibration compaction can be directly obtained by conducting SPT tests on the vibratory compacted sand and gravel. According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on The standard value of the ultimate side friction resistance of vibratory compacted sand and gravel can be obtained by interpolation. The calculation formula for interpolation is as follows: , Given two known data points, x is the point to be interpolated, and y is the interpolation result.

[0041] Table 5.3.5-1 Standard values ​​of ultimate side resistance of piles (kPa)

[0042]

[0043] S1.5 Based on the different soil states after vibration compaction of the bearing layer at the pile tip ( According to Table 5.3.5-2 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", and based on the pile length... The standard values ​​of the ultimate end resistance of piles under different soil conditions can be obtained by interpolation. .

[0044] Table 5.3.5-2 Standard values ​​of ultimate end resistance of piles (kPa)

[0045]

[0046] S2. Calculate the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction. :

[0047] =

[0048] in: The circumference of the pile body; For the first pile Soil layer thickness; This represents the area at the pile tip.

[0049] S3. Standard value of the vertical ultimate bearing capacity of a single pile before vibratory compaction. :

[0050] =

[0051] in: The original soil layer Standard value of ultimate side friction resistance of the layer; This is the standard value of the ultimate end resistance at the pile tip in the original soil layer.

[0052] Easily obtained: the increment of the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction. :

[0053] = - =

[0054] In step (3), the increment of the standard value of the vertical ultimate bearing capacity of a single pile is used. When the surrounding soil layers remain relatively unchanged, optimize the design pile length. ,

[0055] Standard value of vertical ultimate bearing capacity of a single pile before vibratory compaction :

[0056] =

[0057] Obtained: Original pile length - ) /

[0058] Standard value of vertical ultimate bearing capacity of a single pile after vibration compaction :

[0059] =

[0060] Result: Post-processed pile length - ) /

[0061] make: = It is easy to know:

[0062] =

[0063] = - ) / - - ) / .

[0064] The invention will be further explained below with reference to a specific application. The specific application is for a power plant expansion project, covering an area of ​​approximately 240,000 square meters. The boiler area has a large load, and the design uses PHC800 pipe piles with closed ends and a designed pile length of 45m. The piles in the pile cap are relatively dense, with a pile cap embedment depth of 3.0m. The design characteristic value of the single pile bearing capacity is 3500KN (i.e., the standard value of the ultimate bearing capacity of a single pile is 7000KN). The site has a relatively uniform geological distribution, and the detailed geological conditions are shown in the table below:

[0065] Table 1 Detailed geological conditions of the construction area

[0066]

[0067] S1. After the construction of surrounding pipe piles near a certain driven pipe pile is completed, based on geological survey data and different soil layers, appropriate measurement methods are used to obtain the side friction and pile end resistance after different soil layer conditions:

[0068] S1.1 The pile body is filled with soil, and the effect of increased side friction is not considered.

[0069] S1.2 The second and fourth soil layers of the pile body are cohesive soil. The effects of soil compaction and vibration on the soil layer state are manifested in the change of the liquidity index. Three samples were taken from the second and fourth clay layers after vibration compaction to conduct combined liquid and plastic limit tests:

[0070] 2nd layer of soil:

[0071] Determine moisture content = (30.2 + 29.6 + 30.5)% / 3 = 30.1%;

[0072] Liquid limit water content = (29.5 + 30.5 + 37.5)% / 3 = 32.5%;

[0073] Plastic limit moisture content = (22.3 + 21.5 + 28.5) / 3 = 24.1%

[0074] The liquid limit index after vibration compaction is calculated using a formula. ,

[0075] According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on The standard value of the ultimate side friction resistance of the cohesive soil layer after vibration compaction can be obtained by interpolation:

[0076]

[0077] The 4th layer of soil:

[0078] Determine moisture content = (32.5 + 35.8 + 35.8)% / 3 = 34.7%;

[0079] Liquid limit water content = (34.2 + 36.7 + 35.0)% / 3 = 35.3%;

[0080] Plastic limit moisture content = (19.7 + 23.5 + 23.7) / 3 = 22.3%

[0081] The liquid limit index after vibration compaction is calculated using the following formula: ,

[0082] According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on The standard value of the ultimate side friction resistance of the cohesive soil layer after vibration compaction can be obtained by interpolation:

[0083]

[0084] The third soil layer of the S1.3 pile body is silty soil. The effects of soil compaction and vibration on the soil layer state are manifested in the change of void ratio. Three samples were taken from the silty soil layer after vibration compaction and the moisture content was determined by laboratory tests. = (30.6 + 27.4 + 28.1)% / 3 = 28.7%, soil density = (1.85 + 1.72 + 1.89) / 3 = 1.82. The survey report also indicates that Gs = 2.65. The void ratio after vibration compaction can be calculated using this formula. According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on The standard value of the ultimate side friction resistance of the silt layer after vibration compaction can be obtained by interpolation:

[0085] =49.50

[0086] When the 5th and 6th layers of the pile penetrate soil layers consisting of sand and gravel, the effects of soil compaction and vibration on the soil condition are manifested as changes in the standard penetration test (SPT) blow count. By conducting SPT tests at at least three depths on the vibratory-compacted sand and gravel, the blow count after vibratory compaction can be directly obtained. :

[0087] Layer 5 soil: = (26 + 30 + 28) / 3 = 28

[0088] According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on =28, the standard value of the ultimate side friction resistance of the vibratory compacted sand and gravel can be obtained by interpolation:

[0089] = =63.6

[0090] Layer 6 soil: = (37 + 42 + 41) / 3 = 40

[0091] According to Table 5.3.5-1 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", based on =40, the standard value of the ultimate side friction resistance of the vibratory compacted sand and gravel can be obtained by interpolation:

[0092] = =100

[0093] S1.5 If the bearing stratum at the pile tip is layer 5 or 6, the soil state after vibration compaction. =28, 40, according to Table 5.3.5-2 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", and based on the pile length The standard value of the ultimate end resistance of the pile can be obtained by interpolation. =4600 , =5300 .

[0094] S2. According to Article 5.3.5 of the "Technical Specification for Building Pile Foundations JGJ 94-2008", the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction can be obtained. :

[0095] =

[0096] =π*0.8*(50*15+49.5*14+42.8*11+63.6*2+100*3)+5300*π*0.4*0.4 =8547.65KN

[0097] in: The circumference of the pile body; For the first pile Soil layer thickness; This represents the area at the pile tip.

[0098] S3. Standard value of the vertical ultimate bearing capacity of a single pile before vibratory compaction. :

[0099] =

[0100] =π*0.8*(35*15+49*14+30*11+57*2+86*3)+5000*π*0.4*0.4 =7321.17KN > 7000KN, meets the design requirements.

[0101] in: The original soil layer Standard value of ultimate side friction resistance of the layer; This is the standard value of the ultimate end resistance at the pile tip in the original soil layer.

[0102] Easily obtained: the increment of the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction. :

[0103] = - = KN

[0104] If the pile length is reduced at this point, with 5 layers of soil as the bearing layer, the calculated maximum reduction in pile length is 4m:

[0105] =

[0106] =π*0.8*(50*15+49.5*14+42.8*11+63.6*1)+4600*π*0.4*0.4 =7281.96KN > 7000KN, meets the design requirements.

[0107] Because the site survey shows that the soil strata are evenly distributed, considering the soil displacement and vibration densification effects of the driven pipe piles, the length of subsequent piles can be reduced by 4m. This invention combines on-site sampling with indoor tests to quantitatively analyze the soil displacement and vibration densification effects of driven pipe piles, thereby optimizing the pile length design, reducing costs, and saving construction time.

[0108] The above description is merely one embodiment of the present invention, and while it is detailed and specific, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil displacement effect of hammer-driven pipe piles, characterized in that, Includes the following steps: (1) After the construction of the pipe piles near a certain hammer-driven pipe pile is completed, after the construction of this pipe pile, according to the geological survey data and different soil layers, take corresponding measurement methods to sample the soil layer after vibration compaction or conduct standard penetration test to obtain the side friction resistance and pile end resistance after different soil layer states are changed. (2) Calculate the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction using the side friction and pile end resistance obtained in step (1). : = ； in: The circumference of the pile body; For the first pile Soil layer thickness; The area at the pile tip; This is the standard value of the ultimate side friction resistance. This is the standard value of the extreme end resistance; (3) Standard value of vertical ultimate bearing capacity of a single pile before vibration compaction Standard value of vertical ultimate bearing capacity of a single pile after vibration compaction Calculate the increment of the standard value of the vertical ultimate bearing capacity of a single pile after vibration compaction. : = - = ； in: = , The original soil layer Standard value of ultimate side friction resistance of the layer; This is the standard value of the ultimate end resistance at the pile tip in the original soil layer.

2. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (3), the increment of the standard value of the vertical ultimate bearing capacity of a single pile is used. When the surrounding soil layers remain relatively unchanged, optimize the design pile length. , Standard value of vertical ultimate bearing capacity of a single pile before vibratory compaction : = ； Obtained: Original pile length - ) / ; Standard value of vertical ultimate bearing capacity of a single pile after vibration compaction : = ； Result: Post-processed pile length - ) / ; make: = It is easy to know: = = - ） / - - ） / 。 3. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), if the soil layer through which the pile body passes is fill, silt or silty soil, the soil compaction and vibration have little impact on the soil layer state, and the effect of increased side friction is not considered.

4. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), if the soil layer through which the pile penetrates is cohesive soil, the effect of soil compaction and vibration on the soil state is manifested as a change in the liquidity index. The water content is determined by taking samples of the clay layer after vibration compaction and conducting a combined liquid and plastic limit test. Liquid limit water content Plastic limit moisture content The liquid limit index after vibration compaction was calculated using a formula. ,in accordance with The standard value of the ultimate side friction resistance of the cohesive soil layer after vibration compaction was obtained by interpolation. Standard value of ultimate end resistance of pile .

5. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), if the pile body passes through a silty soil layer, the effect of soil compaction and vibration on the soil layer state is manifested as a change in the void ratio. The moisture content is determined by sampling the silty soil layer after vibration compaction and conducting laboratory tests. Soil density The porosity after vibration compaction is calculated using a formula. ,in accordance with The standard value of the ultimate side friction resistance of the silt layer after vibration compaction was obtained by interpolation. Standard value of ultimate end resistance of pile .

6. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), if the pile penetrates a soil layer consisting of sand and gravel, the effect of soil compaction and vibration on the soil state is manifested as a change in the standard penetration test (SPT) blow count. By conducting SPT tests on the sand and gravel after vibration compaction, the blow count after vibration compaction can be directly obtained. ,in accordance with The standard values ​​of the ultimate side friction resistance of the vibratory compacted sand and gravel were obtained by interpolation. Standard value of ultimate end resistance of pile .

7. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), when sampling or conducting standard penetration tests on the soil layer after vibration compaction, the sampling or standard penetration test should be conducted close to the perimeter of the last pipe pile. The distance between the sampling point or the standard penetration test point on the plane and the pile edge should not be greater than 0.3m, and there should be no less than 3 sampling points or standard penetration test points.

8. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), when sampling or conducting standard penetration tests on the soil layer after vibration compaction, samples are taken uniformly in a certain soil layer depth direction or standard penetration tests are conducted.

9. The method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to claim 1, characterized in that, In step (1), when sampling or conducting standard penetration tests on the soil layer after vibration compaction, the sampling or standard penetration test range for the bearing layer at the pile end is from the pile bottom to 0.5m below the pile bottom surface.

10. A method for calculating the increment of vertical bearing capacity of a single pile and optimizing pile length based on the soil squeezing effect of hammer-driven pipe piles according to any one of claims 7-9, characterized in that, In step (1), when sampling or performing standard penetration tests on the vibratory compacted soil layer, the average value obtained is taken as the standard value of the ultimate side friction resistance. and the standard value of the extreme end resistance .

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