A design method of steel pipe pile support system considering shear resistance and support effect
By designing a steel pipe pile support system with shear resistance and supporting function, and calculating the minimum number and arrangement of steel pipe piles, the problems of high construction difficulty and high cost of roadbed settlement in Southwest China were solved, and a fast and reliable roadbed reinforcement effect was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHENGYE ENG & INVESTMENT INC
- Filing Date
- 2022-12-10
- Publication Date
- 2026-08-04
AI Technical Summary
Traditional roadbed reinforcement methods are difficult and costly to implement when dealing with roadbed subsidence under complex geological conditions in Southwest China, and are not suitable for emergency repairs of sudden localized road subsidence.
A steel pipe pile support system is designed that comprehensively considers shear resistance and support. By calculating the minimum number and arrangement of steel pipe piles, the reliability of the reinforcement project at the foundation collapse site is ensured. The effective connection between the steel pipe piles and the road is used to transfer the load to the deep stable rock and resist the sliding thrust of the landslide.
It has achieved the goal of ensuring road stability while reducing engineering costs and construction difficulty, minimizing the possibility of secondary subsidence, and adapting to the needs of roadbed subsidence emergency repair under complex geological conditions in Southwest China.
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Figure CN115717387B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of geotechnical design, specifically relating to a design method for a steel pipe pile support system that comprehensively considers shear resistance and support effects. Background Technology
[0002] To meet the needs of rapid socio-economic development, various regions are vigorously carrying out highway infrastructure construction. In southwestern my country, with its complex geological conditions and abundant rainfall, the stability of roadbeds faces significant challenges. Roadbeds, exposed to the natural environment for extended periods, are subject to uneven deformation due to soil weight, vehicle loads, and rainwater infiltration, affecting driving quality and safety. In severe cases, road subsidence can occur, damaging the road surface and disrupting traffic. Road subsidence caused by soil liquefaction and softening presents even greater challenges for foundation treatment. Traditional reinforcement methods, such as large-scale replacement, grouting, dynamic compaction, granular material piles, and rigid piles, are often difficult to implement, require substantial investment in machinery, materials, and manpower, and are costly, making them unsuitable for emergency support and repair of sudden, localized road subsidence. Summary of the Invention
[0003] The purpose of this invention is to provide a design method for a steel pipe pile support system that comprehensively considers shear resistance and support. By calculating the minimum number of steel pipe piles, the reliability of the reinforcement project at the foundation collapse site can be ensured.
[0004] To address the aforementioned problems, this invention provides a design method for a steel pipe pile support system that comprehensively considers shear resistance and support effects, comprising the following steps: a data measurement step, wherein the following road surface data are measured and obtained: road width L, weight G, uniformly distributed load q, and inclination angle of weak structural surfaces in the subgrade rock mass. internal friction angle of weak structural surfaces Road length on stable bedrock The bedrock of the landslide is subject to its own weight. Top road weight The first stress analysis step involves performing a stress analysis on the bedrock of the landslide body per unit width of the road, establishing calculation equations for the sliding force, anti-sliding force, and residual sliding force of the bedrock. The second stress analysis step involves performing a stress analysis on the system composed of the subsided road and steel pipe piles, establishing vertical force equilibrium equations and horizontal equilibrium equations. Based on the residual sliding force calculation equation, the vertical force equilibrium equation, and the horizontal equilibrium equation, the calculation equation for the overall horizontal shear force borne by all the steel pipe piles is derived, ultimately determining the minimum number of steel pipe piles required.
[0005] Furthermore, the minimum number of steel pipe piles required for the steel pipe pile support system design method that comprehensively considers shear resistance and supporting effects is as follows:
[0006] in, For the yield strength of steel, The outer diameter of the steel pipe pile is... The inner diameter of the steel pipe pile is... For concrete compressive strength, To design a safety factor, Let E be a known constant, and E be the elastic modulus of the steel pipe pile. For cohesion, The length of the central portion located within the bedrock of the landslide body. The friction coefficient between moderately weathered shale and concrete road surface.
[0007] Furthermore, the equation for calculating the sliding force of the bedrock in the above-mentioned design method for steel pipe pile support system that comprehensively considers shear resistance and supporting effects is as follows: The equation for calculating the anti-sliding force of the bedrock of the sliding body is: The equation for calculating the remaining sliding force is: ;in, The sliding force of the bedrock in the landslide. To add loads to the interior of the sliding body The anti-sliding force of the bedrock of the sliding mass. This represents the remaining downward force.
[0008] Furthermore, the vertical force balance equation described in the above design method for steel pipe pile support systems that comprehensively considers shear resistance and support is: The horizontal equilibrium equation is: ;in, This represents the maximum vertical pressure that the steel pipe pile can withstand. The rear end of the road is supported by stable bedrock. The horizontal shear force borne by the entire steel pipe pile group. This represents the horizontal component of the remaining sliding force on the bedrock of the central sliding mass. This is friction.
[0009] Furthermore, the equation for calculating the overall horizontal shear force borne by the steel pipe piles in the above-mentioned design method for steel pipe pile support system that comprehensively considers shear resistance and support is as follows: .
[0010] The above-mentioned technical solution of the present invention has the following beneficial technical effects: For road subsidence caused by subgrade bedding landslide, steel pipe piles are arranged at the subsidence end, and grouting is carried out through drilling at the top of the road to make the steel pipe piles rigidly and effectively connected to the road, thereby transferring the road load to the deep stable rock bearing layer. The steel pipe piles can also resist the sliding thrust generated by the upper sliding body, thus ensuring the overall stability of the road rock subgrade and quickly controlling the excessive subsidence deformation of the road. Calculations can make the reinforcement project more reliable and stable, reducing the possibility of secondary subsidence. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the steel pipe pile support reinforcement for subsided roads in an embodiment of the present invention; Figure 2 This is a stress analysis diagram of the bedrock of the sliding body in an embodiment of the present invention; Figure 3 This is a diagram illustrating the constraint and stress analysis of the steel pipe pile support system for a subsided road in an embodiment of the present invention. Detailed Implementation
[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0013] like Figure 1 As shown, a highway is constructed using concrete pouring. The road width is L, thickness is H, weight is G, and the uniformly distributed load on the road surface is q. According to the survey data, the bearing stratum of the roadbed is moderately weathered shale. A weak structural plane exists within the roadbed rock mass, with a dip angle of θ, cohesion of c, and internal friction angle of θ. The road is continuously exposed within the road area. The road length on stable bedrock is known to be L2, and the road length on sliding bedrock is known to be L1. Surface water infiltration and road surface vibration load cause the weathered shale in the roadbed to slide along the weak sliding surface, which in turn induces the overturning and subsidence of the front end of the road. like Figure 1 As shown, n steel pipe piles are arranged within a width of m at the front end of the road for reinforcement and support. It is known that the elastic modulus of the steel pipe pile is E, the outer diameter is d1, the inner diameter is d2, the top is embedded into the concrete road by drilling and grouting, the embedment length is H, the borehole diameter is D, and the middle part is located in the bedrock of the landslide body with a length of l.
[0014] like Figure 2As shown, a force analysis is performed on the bedrock of a landslide body of unit width. The bedrock is subjected to its own weight W, the weight G2 of the road above it, the uniformly distributed load qL2 of the road surface, and the sliding force T at the potential sliding surface. The sliding force T of the bedrock is as follows: (1) in, To add loads to the interior of the sliding body .
[0015] The anti-slip force R is as follows: (2) in, The length of the slip surface. .
[0016] The remaining sliding force P is as follows: (3) in, The safety factor can be obtained by referring to the table in the "Technical Specification for Building Slope Engineering GB 50330-2013".
[0017] Substituting formulas (1) and (2) into formula (3) and rearranging, we get: (4) Therefore, the horizontal component of the remaining downward force is as follows: (5) refer to Figure 3 A stress analysis was performed on the system consisting of the subsided road and the steel pipe piles. The subsided road was subjected to gravity G and road surface load qL, the rear end of the road was subjected to stable bedrock support force N and friction force f, and the bottom of the steel pipe pile group was subjected to stable bedrock support force F. cr The horizontal component of the remaining sliding force P of the bedrock in the middle of the landslide body h The vertical force equilibrium equations are established as follows: (6) in, This represents the maximum vertical pressure that the steel pipe pile can withstand. , The constant is a known constant whose value is determined based on the constraints and force characteristics of the compression member system. It can be solved using MATLAB scientific computing software or the Casio calculator.
[0018] The equilibrium equations for the horizontal forces are established as follows: (7) in, The horizontal shear force borne by the entire steel pipe pile group; and , The friction coefficient between moderately weathered shale and concrete road surface.
[0019] Combining formulas (5), (6), and (7), the horizontal shear force borne by the steel pipe pile group as a whole is determined. As shown in the following formula: (8) Therefore, the number of steel pipe piles arranged... As shown in the following formula: (9) in, This is the characteristic value of the ultimate shear bearing capacity of a steel pipe pile, which is usually related to the shear strength of the outer steel pipe and the core concrete, and can be expressed as: ,in , The yield strength of the steel can be obtained by referring to tables in the "Code for Design of Steel Structures GB 50017-2017". The cross-sectional area of the concrete. , The compressive strength of concrete can be obtained from the table in the "Code for Design of Concrete Structures GB 50010-2010 (2015 Edition)". Substituting these values and simplifying the expression, we can obtain the final result. (10) then (11) The minimum arrangement quantity is:
[0020] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.
Claims
1. A design method of a steel pipe pile support system considering both shearing resistance and bracing action, characterized by, Includes the following steps: Data measurement step, measuring to obtain the following road data: road width L, weight G, road surface uniform load q, the dip angle of the weak structural plane in the roadbed rock mass , the internal friction angle of the weak structural plane , the length of the road on the stable bedrock , the weight of the sliding body bedrock , the weight of the top road ; The first stress analysis step involves performing a stress analysis on the bedrock of the landslide body per unit width of the road, and establishing the calculation equations for the sliding force, the anti-sliding force, and the remaining sliding force of the bedrock. The second stress analysis step involves performing a stress analysis on the system composed of the subsided road and steel pipe piles, and establishing vertical force equilibrium equations and horizontal equilibrium equations. Based on the remaining sliding force calculation equation, the vertical force balance equation, and the horizontal balance equation, the horizontal shear force calculation equation for all the steel pipe piles is derived, and the minimum number of steel pipe piles to be arranged is finally determined. The minimum number of steel pipe piles to be arranged is: ， in, For the yield strength of steel, The outer diameter of the steel pipe pile is... The inner diameter of the steel pipe pile is... For concrete compressive strength, To design a safety factor, Let E be a known constant, and E be the elastic modulus of the steel pipe pile. For cohesion, The length of the central portion located within the bedrock of the landslide body. The friction coefficient between moderately weathered shale and concrete road surface.
2. The design method for a steel pipe pile support system that comprehensively considers shear resistance and support effects according to claim 1, characterized in that: The sliding force calculation equation of the sliding body base rock is: ; The anti-sliding force calculation equation of the sliding body bedrock is: ; The remaining glide force calculation equation is: ; wherein, is the sliding force of the sliding body on the bedrock, is the additional load inside the sliding body, is the anti-sliding force of the sliding body on the bedrock, is the residual sliding force.
3. The design method for a steel pipe pile support system that comprehensively considers shear resistance and support effects according to claim 2, characterized in that: The vertical force balance equation is as follows: ; The horizontal equilibrium equation is: ; in, This represents the maximum vertical pressure that the steel pipe pile can withstand. The rear end of the road is supported by stable bedrock. The horizontal shear force borne by the entire steel pipe pile group. This represents the horizontal component of the remaining sliding force on the bedrock of the central sliding mass. This is friction.
4. The design method for a steel pipe pile support system that comprehensively considers shear resistance and support effects according to claim 3, characterized in that: The equation for calculating the horizontal shear force borne by the steel pipe pile as a whole is: 。