A method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site

Abstract

The present invention discloses a method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site. The method includes creating a geological three-dimensional model of the undulating bedrock site; determining the length of the cap and the number of piles in the width direction; calculating the cap length and width according to the cap width, the number of piles in the length direction, the reasonable pile spacing, and the diameter of the pipe piles; calculating the cap weight according to the cap length, cap width, and cap burial depth; calculating the single pile bearing capacity required by the soil layer according to the total number of pipe piles required, the axial force at the bottom of each column, and the cap weight; calculating the depth to which the pipe pile end needs to enter the bearing layer according to the single pile bearing capacity required by the soil layer; calculating the actual length of each pipe pile according to the depth to which the pipe pile end needs to enter the bearing layer; and finding the matching method that is closest to the actual length of each pipe pile based on the conventional single-section pile lengths to achieve precise pile matching. The present invention guides construction, reduces project investment, and shortens construction period.

Description

Technical Field

[0001] The invention belongs to the technical field of building structures, and particularly relates to a method for arranging the lengths of high-strength prestressed pipe piles according to undulating bedrock sites. Background Art

[0002] A low, weathered, denuded hill lies along the gentle, shallow, and reefal islands east of the southern tip of a peninsula. Drilling reveals that the thickness of the artificially filled medium-fine sand layer varies across different parts of the site, indicating a later secondary fill. The silt layer is generally discontinuous and lens-shaped, with locally varying thicknesses of residual layers. The underlying bedrock is an early granitic intrusive rock, locally interbedded with diorite xenoliths. The overall composition is medium- to fine-grained biotite monzogranite, with localized medium- to coarse-grained content. Its color is off-white to light gray. The main mineral components are potassium feldspar (30-35%), plagioclase (35-40%), quartz (25%), and biotite (5%). Minerals range in size from 2 to 5 mm, with a few larger than 5 mm. Alteration minerals primarily include sericite, chlorite, and chlorite. The entire bedrock weathering layer exhibits the following characteristics: from west to east, the fully weathered layer gradually thins in thickness. From north to south, the fully weathered layer exhibits a wavy pattern, from thick to thin in the eastern part of the site and from thin to thick in the western part. The elevation of the weathered rock roof on the site fluctuates greatly.

[0003] The foundation of this project uses hammer-type PHC600-130-AB high-strength prestressed pipe piles with a pile diameter of 600 and a pile body concrete strength of C80. The bearing layer at the pile end is highly weathered bedrock. In order to control foundation settlement and ensure the bearing capacity of the pile foundation, the design requires that the depth of the pile end entering the bearing layer be ≥2 meters, and the characteristic value of the vertical bearing capacity of a single pile is 2100kN. The pile end entering the bearing layer and the pile foundation penetration are used as the dual-control final pile standards.

[0004] When prestressed pipe piles are used in sites with undulating bedrock, such as those in existing engineering foundations, the uncertainty of the bearing stratum elevation leads to a wide range of pile length variations. Excessive pile lengths result in excessive cuts and waste, while short pile lengths lead to excessive splicing, exceeding regulatory requirements. The challenge is determining the depth of the pile end into the bearing stratum and achieving precise pile placement through rational optimization of pile sections. Therefore, a new method for matching the length of high-strength prestressed pipe piles based on undulating bedrock is needed. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the above-mentioned background technology and provide a method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site.

[0006] The technical solution adopted by the present invention is: a method for matching the length of high-strength prestressed pipe piles according to the undulating bedrock site, comprising:

[0007] Step 1: Create a geological 3D model of the bedrock undulating site;

[0008] Step 2: Determine the number of piles in the length and width directions of the foundation;

[0009] Step 3: Determine the total number of pipe piles required based on the length and width of the platform;

[0010] Step 4: Calculate the platform length and width based on the platform width, number of piles in the length direction, reasonable pile spacing, and pipe pile diameter;

[0011] Step 5: Calculate the weight of the cap based on the cap length, cap width and cap burial depth;

[0012] Step 6: Calculate the single pile bearing capacity required by the soil layer based on the total number of pipe piles required, the axial force at the bottom of each column, and the weight of the cap;

[0013] Step 7: Calculate the depth that the pile tip needs to enter the bearing layer based on the single pile bearing capacity required by the soil layer;

[0014] Step 8: Calculate the actual length of each pipe pile based on the depth that the pile end needs to enter the bearing layer;

[0015] Step 9: Based on the conventional length of single-section piles, find the matching method that requires the total length of pipe piles closest to the actual length of each pipe pile to achieve accurate pile matching.

[0016] The abutment length A and abutment width B are determined by the following formula:

[0017] A=(n1-1)s d +d

[0018] B=(n2-1)s d +d

[0019] Among them, n1 and n2 are the number of pipe piles along the length A and width B of the platform respectively; S d —Reasonable pile spacing; d—Pile diameter.

[0020] Platform weight G k Determined by the following formula:

[0021] G k =rABd1

[0022] Wherein, d1 is the burial depth of the foundation; r is the weight of the foundation and the fill above it, which is generally taken as 20kN / m 3 , take the floating weight underwater.

[0023] The single pile bearing capacity R required by the soil layer a Determined by the following formula:

[0024]

[0025] n=n1*n2

[0026] Among them, F k —Axial force at the base of each column; n—Total number of pipe piles required.

[0027] The depth w that the pile tip needs to enter the bearing layer is determined by the following formula:

[0028] w=(2R a -πd∑q sik l i -q pk A p ) / q sik

[0029] Among them, q sik — friction; q pk —End resistance; A p —pile tip area; l i —Thickness of each soil layer.

[0030] The actual length L of each pile is calculated using the following formula:

[0031] L=l1+l2+l3...+l i +w-d1

[0032] According to the various combinations of pipe pile sections with conventional single-section pile lengths, the number of pile section heads j≤3, j=j1+j2+j3+j4,

[0033]

[0034] Wherein, j1, j2, j3, j4 = 0, 1, 2, 3; L1, L2, L3, L4 are the lengths of conventional single-section piles;

[0035] Through the above combinations, we can find the matching method that the required total length L' of the pipe piles is closest to the actual length L of each pipe pile, so as to achieve accurate pile matching.

[0036] In the above steps, the axial force F at the bottom of each column is read according to the structure of the upper structure in the geological 3D model. k and the number of piles n1 and n2 along the width and length of the abutment.

[0037] In the above steps, the thickness of each soil layer l1, l2, l3...l in the bedrock undulating site is determined according to the geological three-dimensional model. i And the buried depth of the pile cap is d1.

[0038] In the above steps, according to the geological survey report, the pile side friction resistance q sik , end resistance q pk , pile diameter d, pile tip area A p .

[0039] This method establishes a three-dimensional geological and pile foundation model, using parametric design to establish the correspondence between pile foundations and geological layers, thereby determining pile length and bearing stratum depth. During the pile foundation construction process, the length of each pile is determined individually on the uneven bedrock. Through the appropriate matching of pile sections, precise pile placement is achieved, guiding construction efforts, reducing project investment, and shortening construction periods.

[0040] The 3D design software uses a geological 3D model created as input. By determining the spatial relationship between the different strata at the pile location and the precast piles, the thickness of the soil layer the precast piles penetrate and the bearing layer at the pile ends are determined. The bearing capacity of the precast piles is then rapidly calculated using the physical parameters of the soil layer. After adjusting the pile length to meet design requirements, a parametric design is used to establish a correspondence between the pile foundation and the geological sub-surface. By properly matching pile sections, precise pile placement is achieved, guiding construction, reducing project investment, and shortening the construction period.

[0041] The present invention uses a three-dimensional geological model that can objectively reflect the actual geological conditions of the project, facilitating rapid and accurate understanding of engineering geology by all parties involved in the project, and providing very intuitive conditions for project site selection and design guidance in the early stages of the project.

[0042] The present invention combines pile length with a three-dimensional geological model to accurately determine the actual length of each pile, providing a basis for foundation design.

[0043] In areas with significant bearing stratum fluctuations, the actual length of each pile can vary depending on the final pile conditions required by the design. Three-dimensional modeling accurately reflects the buried depth of the bearing stratum at the pile end, allowing for the determination of each pile length. This accelerates construction, reduces costs, and shortens the construction period. This project employed 1,230 pile foundations, ranging in length from 16 to 36 meters. Optimized pile combinations were employed using single-section lengths of 6m, 10m, and 12m. This reduced the number of pipe pile joints and avoided the waste caused by unnecessary pile cutting, saving 2.53 million yuan in project investment.

[0044] The present invention can help analyze problems encountered during foundation construction and is beneficial to solving and handling on-site construction problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a three-dimensional model diagram of the upper structure structure and geology;

[0046] Figure 2 This is the layout diagram of prestressed pipe piles;

[0047] Figure 3 Schematic diagram of the prestressed pile body;

[0048] Figure 4 Schematic diagram of pipe piles entering the bearing layer;

[0049] Figure 5Optimization diagram for pile matching.

[0050] Among them, 1-superstructure structure, 2-pipe piles, 3-backfill sand layer, 3a-silty soil layer, 4-residual layer, 5-strongly weathered granite layer (pile end bearing layer), 6-moderately weathered granite layer, 7-cap, 8-cushion, 9-pile head. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not constitute a limitation to the present invention.

[0052] like Figure 1-5 As shown, the present invention includes

[0053] Step 1: Create a geological 3D model of the bedrock undulating site;

[0054] Step 2: Determine the number of piles in the length and width directions of the foundation;

[0055] Step 3: Determine the total number of pipe piles required based on the length and width of the platform;

[0056] Step 4: Calculate the platform length and width based on the platform width, number of piles in the length direction, reasonable pile spacing, and pipe pile diameter;

[0057] Step 5: Calculate the weight of the cap based on the cap length, cap width and cap burial depth;

[0058] Step 6: Calculate the single pile bearing capacity required by the soil layer based on the total number of pipe piles required, the axial force at the bottom of each column, and the weight of the cap;

[0059] Step 7: Calculate the depth that the pile tip needs to enter the bearing layer based on the single pile bearing capacity required by the soil layer;

[0060] Step 8: Calculate the actual length of each pipe pile based on the depth that the pile end needs to enter the bearing layer;

[0061] Step 9: Based on the conventional length of single-section piles, find the matching method that requires the total length of pipe piles closest to the actual length of each pipe pile to achieve accurate pile matching.

[0062] The abutment length A and abutment width B are determined by the following formula:

[0063] A=(n1-1)s d +d

[0064] B=(n2-1)s d +d

[0065] Among them, n1 and n2 are the number of pipe piles along the length A and width B of the platform respectively; S d—Reasonable pile spacing; d—Pile diameter.

[0066] Platform weight G k Determined by the following formula:

[0067] G k =rABd1

[0068] That is G k =r((n1-1)s d +d)((n2-1)s d +d)d1

[0069] Among them, d1 is the burial depth of the foundation; r is the weight of the foundation and the fill above it.

[0070] The single pile bearing capacity R required by the soil layer a Determined by the following formula:

[0071]

[0072] n=n1*n2

[0073] Among them, F k —Axial force at the base of each column; n—Total number of pipe piles required.

[0074] The depth w that the pile tip needs to enter the bearing layer is determined by the following formula:

[0075] w=(2R a -πd∑q sik l i -q pk A p ) / q sik

[0076] That is, w=(2(F k +r((n1-1)s d +d)((n2-1)s d +d)d1) / n-πd∑q sik l i -q pk A p ) / q sik

[0077] Among them, q sik — friction; q pk —End resistance; A p —pile tip area; l i —Thickness of each soil layer.

[0078] The actual length L of each pile is calculated using the following formula:

[0079] L=l1+l2+l3...+li +w-d1

[0080] Right now

[0081] L=l1+l2+...+l i +(2(F k +r((n1-1)s d +d)((n2-1)s d +d)d1) / n-πd∑q sik l i -q pk A p ) / q sik -d1

[0082] According to the various combinations of pipe pile sections with conventional single-section pile lengths, the number of pile section heads j≤3, j=j1+j2+j3+j4,

[0083]

[0084] Wherein, j1, j2, j3, j4 = 0, 1, 2, 3; L1, L2, L3, L4 are the lengths of conventional single-section piles;

[0085] Through the above combinations, we can find the matching method that the required total length L' of the pipe piles is closest to the actual length L of each pipe pile, so as to achieve accurate pile matching.

[0086] In the above steps, the axial force F at the bottom of each column is read according to the structure of the upper structure in the geological 3D model. k and the number of piles n1 and n2 along the width and length of the abutment.

[0087] In the above steps, the thickness of each soil layer l1, l2, l3...l in the bedrock undulating site is determined according to the geological three-dimensional model. i And the buried depth of the pile cap is d1.

[0088] In the above steps, according to the geological survey report, the pile side friction resistance q sik , end resistance q pk

[0089] The diameter of a single section of a commonly used high-strength prestressed pipe pile ranges from 6 to 12 meters. Based on the actual length of a single pile, the length of each section is optimized, the number of connections and cuts are controlled, and the pile configuration data for each pile is determined and marked on the construction drawing.

[0090] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A method for matching the length of high-strength prestressed pipe piles according to the undulating bedrock site, characterized by: include Step 1: Create a geological 3D model of the bedrock undulating site; Step 2: Determine the number of piles in the length and width directions of the foundation; Step 3: Determine the total number of pipe piles required based on the length and width of the platform; Step 4: Calculate the length of the cap based on the number of piles in the cap length direction, the reasonable pile spacing, and the diameter of the pipe piles. Calculate the width of the cap based on the number of piles in the cap width direction, the reasonable pile spacing, and the diameter of the pipe piles. Step 5: Calculate the weight of the cap based on the cap length, cap width and cap burial depth; Step 6: Calculate the single pile bearing capacity required by the soil layer based on the total number of pipe piles required, the axial force at the bottom of each column, and the weight of the cap; Step 7: Calculate the depth that the pile tip needs to enter the bearing layer based on the single pile bearing capacity required by the soil layer; Step 8: Calculate the actual length of each pipe pile based on the depth that the pile end needs to enter the bearing layer; Step 9: Based on the conventional length of single-section piles, find the matching method that the total length of the required piles is closest to the actual length of each pile to achieve accurate pile matching; According to the various combinations of pipe pile sections made from conventional single-section pile lengths, the number of pile joints j = j1 + j2 + j3 + j4, Wherein, j1, j2, j3, j4 = 0, 1, 2, 3; L1, L2, L3, L4 are the lengths of conventional single-section piles; Through the above combinations, we can find the matching method that the required total length L' of the pipe piles is closest to the actual length L of each pipe pile, so as to achieve accurate pile matching.

2. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 1, characterized in that: The abutment length A and abutment width B are determined by the following formula: A=(n1-1)s d +d B=(n2-1)s d +d Among them, n1 and n2 are the number of pipe piles along the length A and width B of the platform respectively; S d —Reasonable pile spacing; d—Pile diameter.

3. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 2, characterized in that: Platform weight G k Determined by the following formula: G k =rABd1 Among them, d1 is the burial depth of the foundation; r is the weight of the foundation and the fill above it.

4. The method for arranging the length of high-strength prestressed pipe piles according to claim 3, wherein: The single pile bearing capacity R required by the soil layer a Determined by the following formula: n=n1*n2 Among them, F k —Axial force at the base of each column; n—Total number of pipe piles required.

5. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 4, characterized in that: The depth w that the pile tip needs to enter the bearing layer is determined by the following formula: w=(2R a -πd∑q sik l i -q pk A p ) / q sik Among them, q sik — friction; q pk —End resistance; A p —pile tip area; l i —Thickness of each soil layer.

6. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 5, characterized in that: The actual length L of each pile is calculated using the following formula: <h2 style=";text-align:left;direction:ltr">L = l1 + l2 + l3... + l<h2 style=";text-align:left;direction:ltr"> i <h2 style=";text-align:left;direction:ltr"> +w-d1.

7. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 4, characterized in that: Read the axial force F at the base of each column according to the upper structure structure in the geological 3D model k and the number of piles n1 and n2 along the length and width of the foundation.

8. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 5, characterized in that: Determine the thickness of each soil layer l1, l2, l3...l on the bedrock undulating site based on the geological three-dimensional model i And the buried depth of the pile cap is d1.

9. The method for arranging the length of high-strength prestressed pipe piles according to the undulating bedrock site according to claim 5, characterized in that: Obtain the pile side friction resistance q of the soil layer according to the geological survey report sik , end resistance q pk , pile diameter d, pile tip area A p .

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