Intelligent design method for asymmetric combination joint of pipe section based on performance matching

Abstract

This invention provides an intelligent design method for asymmetric composite joints of pipe jacking segments based on performance matching, comprising the following steps: acquiring geological information and structural data of the target underground pipe jacking, and solving for the target bending moment required at the joint location. M req Target bending stiffness K req Select the joint's structural form, determine the joint's structural parameters, and calculate the joint's actual bending stiffness. K joint The actual bending stiffness obtained is matched and verified with the target bending stiffness. If the conditions are met... K joint ≥ K req If the match is successful, then the joint is successfully matched; if not, adjust the joint by increasing the bolt diameter, increasing the number of reinforcing bars, or using higher-strength concrete, or by adopting other joint construction methods; repeat the above steps after adjustment and re-verify until the matching conditions are met. Using the design method of this invention, performance matching is precise, achieving both safety and economy, fundamentally optimizing joint stiffness and avoiding dilemmas.

Description

Technical Field

[0001] This invention relates to the field of prefabricated rectangular pipe jacking tunnel engineering technology, and in particular to an intelligent design method for asymmetric combination joints of pipe jacking sections based on performance matching. Background Technology

[0002] With the expansion of urban underground space development, large-section rectangular pipe jacking technology has become a key technology for urban underpasses, integrated utility tunnels, and other projects due to its advantages such as minimal impact on surface traffic, no need to relocate underground pipelines, low construction noise, and low overall cost. Pipe jacking tunnels are assembled from multiple pipe sections pushed forward sequentially. The joints between the pipe sections are the core components ensuring the tunnel's structural safety and water-stopping performance; their mechanical properties directly determine the overall load-bearing capacity and deformation adaptability of the tunnel body.

[0003] Currently, the pipe jacking joints widely used in engineering are mostly symmetrical designs, meaning that the soil-facing side and the soil-repellent side of the joint use the exact same connection method and structural dimensions. For example, reinforced concrete rectangular pipe jacking joints often use bent bolt connections. However, this "one-size-fits-all" design has significant limitations and is difficult to adapt to actual engineering needs.

[0004] First, the mismatch between design and stress leads to low structural efficiency. The stress environments and action modes on both sides of the joint are fundamentally different: the side facing the soil primarily bears soil pressure, while the side facing away from the soil bears the jacking force and corresponding bending moment transmitted from the jacking equipment. The symmetrical design, forced to meet the most unfavorable working conditions, resulted in overall reinforcement, leading to material waste, structural bulkiness, and performance redundancy on the non-controlling side.

[0005] Secondly, the choice of stiffness presents a dilemma. Insufficient stiffness can lead to excessive deformation and opening of the joints, causing the risk of water leakage and unfavorable redistribution of internal forces in the pipe sections; while excessive stiffness makes the tunnel structure too rigid, and when passing through uneven strata or uneven settlement, secondary stresses cannot be released through joint rotation, which can easily lead to the crushing or cracking of the concrete in the pipe sections. Furthermore, it is difficult to accurately match the requirements with the fixed stiffness of symmetrical joints.

[0006] Finally, there is a lack of scientific selection methods. Joint design and selection heavily rely on engineers' experience and rough estimates, lacking a method to quickly and quantitatively match the mechanical properties of the joint with engineering loads and geological conditions, resulting in low efficiency and difficulty in ensuring the economy and safety of the solution. Summary of the Invention

[0007] To address the above technical problems, this invention discloses an intelligent design method for asymmetric combined joints of pipe jacking sections based on performance matching, which can comprehensively solve problems such as rigid joint design, performance-condition mismatch, and reliance on experience in the prior art.

[0008] The technical solution adopted by this invention is as follows:

[0009] A smart design method for asymmetric combined joints of pipe jacking sections based on performance matching includes the following steps:

[0010] Step S1: Obtain the geological information and structural data of the target underground pipe jacking project, and calculate the target bending moment required at the joint location based on the geological information and the structural data of the pipe jacking project. M req Target bending stiffness K req ;

[0011] Step S2: Select the joint construction type, determine the joint construction parameters, and calculate the actual bending stiffness of the joint. K joint The joint's construction satisfies the following: the soil-facing connection and the soil-repelling connection adopt different structural forms and / or different mechanical properties of the connecting parts.

[0012] Step S3: Match and verify the actual bending stiffness of the joint obtained in step S2 with the target bending stiffness in step S1. If the requirements are met... K joint ≥ K req If the match is successful, the connector design scheme will be output.

[0013] If the requirements are not met, adjust the joint construction parameters by increasing the bolt diameter, increasing the number of reinforcing bars, or using higher strength concrete; repeat step S2 after adjustment, and then re-verify until the matching conditions are met.

[0014] This technical solution constructs a complete quantitative design closed loop. It establishes demand-side calculation formulas using the load-structure method to accurately determine the design bending moment and stiffness requirements at the joint location. Simultaneously, based on the structural parameters of the asymmetric combined joint, it establishes supply-side calculation formulas to precisely derive its bending stiffness and ultimate bearing capacity. Finally, through bidirectional matching and verification of the two formula systems, it achieves precise adaptation between joint performance and engineering requirements, elevating the design process from "qualitative experience" to "quantitative formulas," forming a standardized design method that can be directly implemented, thereby ensuring the safety and adaptability of the pipe jacking structure under various complex working conditions.

[0015] As a further improvement of the present invention, in step S1, a finite element model is established to solve the target bending moment required at the joint location through numerical simulation. M req The target bending stiffness is calculated according to formula (1). K req The finite element model used is a model based on existing technology.

[0016] (1),

[0017] in, θ allow The maximum allowable angle of rotation for the joint is determined by the waterproof rating and pipe section deformation control requirements.

[0018] As a further improvement of the present invention, the joint includes a tenoned tube segment and a tongue-and-groove tube segment, which are connected on the inner and outer sides of the tube segment by a connector; the connector includes at least one of the following: a beveled bolt, a bent bolt, a C-shaped channel steel, an H-shaped channel steel, and a short bolt.

[0019] As a further improvement of the present invention, in step S2, the joint is an asymmetrical combined joint, and the bending stiffness of the asymmetrical combined joint is calculated using formula (2):

[0020] (2),

[0021] in, K soil-side For the bending stiffness of the soil-facing joint, K back-side Let η be the bending stiffness of the joint on the soil-facing side, and η be the asymmetric coordination coefficient of the pipe jacking joint. The asymmetric coordination coefficients of different asymmetric combined joints are obtained through experimental calibration. The bending stiffness of the joints on the soil-facing and soil-facing sides of the asymmetric combined joints is used as... K soil-side and K back-side .

[0022] As a further improvement of the present invention, the asymmetric coordination coefficients of different asymmetric combination joints are as follows: CHC-TSB combination joint, η=0.60; CCC-TSB combination joint, η=0.55; CB-TSB combination joint, η=0.42; CB-CHC combination joint, η=0.45; CCC-CHC combination joint, η=0.40.

[0023] In the TSB joint, the tongue-and-groove segments are connected by diagonal bolts;

[0024] In a CCC joint, the convex tenon segment and the concave tenon segment are connected by two C-shaped channel steels to form a three-C shaped steel-concrete joint.

[0025] In CHC joints, the convex and concave tenon segments are connected by C-shaped and H-shaped channel steel to form a double C-shaped steel-concrete joint.

[0026] In a CB joint, the male and female tenon segments are connected by two C-shaped channel steels and short bolts to form a channel steel-bolt joint.

[0027] As a further improvement of the present invention, the bending stiffness of the bolted connection in the joint is calculated using formula (3):

[0028] (3),

[0029] in, E c , E b These are the elastic moduli of concrete and bolts, respectively. I c The moment of inertia of the cross section of the tenon / dental tenon segment. n b These represent the number of bolts. A b This represents the cross-sectional area of ​​a single bolt. e The distance from the bolt to the neutral axis of the cross section; the bolt includes at least one of a wedge bolt and a short bolt;

[0030] The bending stiffness of the channel steel connection part in the joint is calculated using formula (4):

[0031] (4),

[0032] in, E steel , E s The elastic modulus of C-shaped or H-shaped channel steel and concrete. n s , n steel These are the number of reinforcing bars and channel steel, respectively. I s The moment of inertia of a single reinforcing bar section. I steel The moment of inertia of the section of C-shaped or H-shaped channel steel; the channel steel includes at least one of C-shaped and H-shaped channel steel. This is used to calculate the bending stiffness of the joint on the soil-facing side. K soil-side Flexural stiffness of backfill side joint K back-side At that time, depending on the structural form of the joint on the soil-facing or soil-repellent side, the sum of the bending stiffness of the joint connections is considered. For example, in a CHC joint, the tenon and tongue segments are connected by C-shaped and H-shaped channel steels to form a double C-shaped steel-concrete joint. If the C-shaped and H-shaped channel steels are located on the soil-facing side, then the bending stiffness on the soil-facing side = K. single1 +K single2 , where K single1 K single2 The bending stiffness of the C-shaped channel steel connection and the H-shaped channel steel connection are respectively calculated according to formula (4).

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] First, the design method of this invention achieves precise performance matching, balancing safety and economy. Through asymmetrical design, the structural forms of the soil-facing and soil-repelling sides of the joint are highly adapted to their respective stress characteristics (soil pressure, jacking force), overcoming the inherent "one-size-fits-all" defects of symmetrical joints. This not only significantly improves the overall load-bearing efficiency and reliability of the joint, but also avoids material waste through targeted optimization design, achieving lower costs at the same safety level, or higher safety reserves at the same cost.

[0035] Secondly, it fundamentally optimizes joint stiffness and avoids the dilemma of excessive flexibility. The diverse joint combinations provided by the technical solution of this invention form a "solution library" covering different stiffness ranges. Designers can accurately select the optimal solution that combines rigidity and flexibility according to the specific requirements of the geological deformation capacity and the sensitivity of the surrounding environment, thereby effectively avoiding the dilemma of joints being "too flexible and prone to leakage" or "too rigid and prone to brittle fracture" in traditional designs.

[0036] Third, the technical solution of this invention has wide adaptability and strong ability to cope with complex engineering projects. For different scenarios such as soft soil strata, high water pressure, and uneven soft and hard soil, parameters (such as load combination coefficients and structural dimensions) can be adjusted by formulas, so that this invention can flexibly and quickly respond to the challenges of various complex geological conditions and special working conditions (such as uneven soft and hard soil strata, high water pressure, and adjacent construction), which greatly enhances the adaptability and reliability of pipe jacking technology in different application scenarios. Attached Figure Description

[0037] Figure 1 This is a front view of the CHC-TSB connector according to an embodiment of the present invention.

[0038] Figure 2 This is a top view of the CHC-TSB connector according to an embodiment of the present invention.

[0039] Figure 3 This is a perspective view of the CHC-TSB connector according to an embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of the channel steel reinforcement connection of the CHC-TSB joint according to an embodiment of the present invention.

[0041] Figure 5 This is a structural dimension diagram of an engineering embodiment of the present invention.

[0042] Figure 6 This is a finite element model diagram of a stratum containing underground joints according to an embodiment of the present invention.

[0043] Figure 7This is a diagram showing the numerical simulation bending moment results of an embodiment of the present invention.

[0044] The reference numerals in the figures include:

[0045] 1-Tongue segment, 2-Tongue segment, 3-Angle bolt, 4-C-shaped channel steel, 5-H-shaped channel steel, 6-Reinforcing bar. Detailed Implementation

[0046] The preferred embodiments of the present invention will be described in further detail below.

[0047] A performance-matching-based intelligent design method for asymmetric composite joints in pipe jacking systems is proposed. Its core lies in constructing a complete quantitative design closed loop: First, a finite element model (using existing technology) is established to numerically simulate and solve for the required mechanical performance indicators such as bending moment and stiffness at the joint location. Simultaneously, based on the structural parameters of the asymmetric composite joint (concrete, reinforcing steel, bolts, etc.), supply-side calculation formulas are established to accurately derive its bending stiffness and ultimate bearing capacity. Finally, through bidirectional matching and verification of the calculation results, the joint performance is precisely matched to engineering requirements, elevating the design process from "qualitative experience" to "quantitative formula," forming a standardized design method that can be directly implemented.

[0048] The asymmetric joint involved uses connectors with different structural forms and / or different mechanical properties for the soil-facing and soil-repelling connection parts, thus forming an asymmetric structure with adjustable performance.

[0049] The joint basically consists of mating tenon and tongue segments, which are combined on the inner and outer sides of the segments by various connectors. These connectors include, but are not limited to, beveled bolts, bent bolts, C-channel steel, H-channel steel, and short bolts.

[0050] By combining the above basic components, various basic joint types with different mechanical properties can be formed, for example:

[0051] 1. A TSB joint (or simply TSB joint) can be formed by a tenoned tube segment, a concave tenoned tube segment, and a beveled bolt.

[0052] 2. A three-C steel-concrete joint (referred to as CCC joint) can be formed by a tenoned tube segment, a concave tenoned tube segment, and two C-shaped channel steels.

[0053] 3. Double C-shaped steel-concrete joints (CHC joints) can be formed by tenoned pipe segments, concave tenoned pipe segments, C-shaped channel steel, and H-shaped channel steel.

[0054] 4. A channel steel-bolt joint (abbreviated as CB joint) can be formed by a tenoned tube segment, a concave tenoned tube segment, two C-shaped channel steels, and short bolts.

[0055] Depending on the actual engineering requirements, including varying earth pressures and project costs, different types of joints can be selected and combined. Asymmetric joint combinations include, but are not limited to, the following:

[0056] 1. CHC-TSB asymmetric combination connector; its structure is as follows: Figures 1-4 As shown.

[0057] 2. CCC-TSB asymmetrical combination connector.

[0058] 3. CCC-TSB asymmetrical combination connector.

[0059] 4. CCB-CCC asymmetrical combination joint.

[0060] The intelligent design method for asymmetric combined joints of pipe jacking sections based on performance matching includes the following steps:

[0061] S1. Obtain the geological information and pipe jacking structure data of the target underground pipe, and solve the bending moment and bending stiffness according to the geological information and pipe jacking structure data by formula or finite element software.

[0062] Specifically, first determine the requirements on the demand side, and then calculate the stress requirements (bending moment, stiffness threshold) at the joint location.

[0063] Based on the actual conditions of the target project, a finite element model is established to solve the target bending moment required at the joint location through numerical simulation. M req and target stiffness K req This provides a basis for matching. Specifically, a parametric, detailed model of the joint is established using finite element software (such as ABAQUS or ANSYS). Parameters include, but are not limited to: bolt diameter, grade, and inclination angle; channel steel type and dimensions; concrete strength grade; and rebar diameter.

[0064] Target bending moment M req The bending moment at the joint location is derived from the numerical simulation results. The target bending stiffness is calculated according to formula (1) (based on deformation control requirements). K req ;

[0065] (1),

[0066] in, θ allow The maximum allowable angle of rotation for the joint is determined by the waterproof rating and pipe section deformation control requirements, and is usually taken as 10. -3 ~5×10 -3 rad.

[0067] S2. Determine the joint structure and parameters, and calculate the joint bending stiffness.

[0068] Based on the joint construction parameters (concrete, steel bars, bolts, etc.), the actual bending stiffness of the asymmetric composite joint is calculated using formula (2). K joint .

[0069] (2),

[0070] in, K soil-side The bending stiffness of the soil-facing joint is given in kN·m / rad. K back-side η is the bending stiffness of the back soil side joint (KN·m / rad), and η is the asymmetric coordination coefficient of the pipe jacking joint. The asymmetric coordination coefficient of different asymmetric combined joints is obtained by experimental calibration.

[0071] The values ​​of the asymmetric coordination coefficients for different asymmetric combination joints are shown in Table 1.

[0072] Table 1. Asymmetric Coordination Coefficients for Different Asymmetric Combined Joints

[0073]

[0074] For bolted joints, such as TSB joints, the bending stiffness is calculated using formula (3):

[0075] (3),

[0076] For channel steel joints, such as CCC and CHC joints, the bending stiffness is calculated using formula (4):

[0077] (4),

[0078] in:

[0079] E c , E s , E steel These are the elastic moduli (GPa) of concrete, reinforcing steel, C-shaped channel steel, or H-shaped channel steel, respectively.

[0080] I c , I steel , I s The moments of inertia (m) of the sections of concrete segments, C-shaped or H-shaped channel steel, and single reinforcing bars, respectively. 4 );

[0081] n s , n steel , n b The quantities (in units) of reinforcing bars, channel steel, and bolts, respectively.

[0082] A b The cross-sectional area of ​​a single bolt (m²) 2 );

[0083] e The distance (m) from the bolt to the neutral axis of the cross section.

[0084] S3, perform matching verification and parameter optimization.

[0085] If satisfied K joint ≥ K req If the match is successful, the connector design scheme will be output.

[0086] If the requirements are not met, adjust the structural parameters using the formula: such as increasing the bolt diameter, increasing the number of reinforcing bars, or using higher-strength concrete; after adjustment, recalculate using the supply-side formula. K joint Repeat the verification process until the matching conditions are met.

[0087] The following description uses specific examples to illustrate the point.

[0088] S1.1 Based on actual engineering conditions such as structural dimensions, soil parameters, and material properties, a finite element model is established. The bending moment and rotation angle at the joint location are solved through numerical simulation. Initially, the joints are positioned in the middle of the left and right sides of the structure. The structural dimensions in this embodiment are as follows: Figure 5 As shown. A finite element model of the strata containing underground joints is established as follows. Figure 6 As shown. The numerical simulation bending moment results are as follows. Figure 7 As shown.

[0089] The bending moment at the joint location S1.2 is 268 kN·m, and the maximum rotation angle is taken as 5×10. -3 rad, obtained by solving according to formula (1) K req= 53600 KN·m / rad.

[0090] S2.1 Initially, a CCC-TSB joint is adopted, with η=0.6. CCC is used on the soil-facing side, and TSB is used on the soil-repelling side.

[0091] The side facing the soil:

[0092] Ec =34.5 GPa, I c =0.0104 m 4 , n s =10 pieces, n steel =2, E s =206 GPa, I s =3.07 × 10 −9 m 4 .

[0093] Substituting into formula (4) and solving, we get:

[0094] K soil-side = K single = E c ×I c +n s ×E s ×I s +n steel ×E steel ×I steel =34.5×10 6 ×0.0104+10×206×10 6 ×3.07× 10 −9 +2×206×10 6 ×17.9×10 −6 =366000 kN·m / rad

[0095] Back soil side:

[0096] E c =34.5 GPa, I c =2×10 −3 m 4 n b =5 pieces, E b =206 GPa, A b =0.00196 m 2 (M20 bolt) e =0.2m.

[0097] Substituting into formula (3) and solving, we get:

[0098] K back-side = K single = E c ×I c +n b ×E b ×A b ×e 2 =34.5×10 6 ×2×10 −3 +5×206×10 6 ×0.00196×0.2 2 =149000 kN·m / rad

[0099] Calculate the total stiffness of the combined joint according to formula (2):

[0100]

[0101] S3.1 Match Validation:

[0102]

[0103] The conditions are met, and the match is successful.

[0104] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A performance-based matching intelligent design method for an asymmetric combined joint of a pipe section of a pipe jacking, characterized in that: Comprising the following steps: Step S1, obtaining geological information of a target underground pipe jacking and structure data of the pipe jacking, and solving a target bending moment required to be borne by a joint position according to the geological information and the structure data of the pipe jacking M req and the target bending stiffness K req ; Step S2, selecting the configuration form of the joint, determining the joint configuration parameters, and calculating the actual bending stiffness of the joint K joint ; the configuration form of the joint meets: the connecting parts on the soil-facing side and the soil-backing side adopt connecting pieces with different structural forms and / or different mechanical properties; the joint is a non-symmetrical combined joint, and the bending stiffness of the non-symmetrical combined joint is calculated by using formula (2): （2）， wherein, K soil-side is the bending stiffness of the topsoil side joint, K back-side is the bending stiffness of the backsoil side joint, and η is the asymmetric synergy coefficient of the pipe joint. Step S3, matching verification is performed on the actual bending stiffness of the joint obtained in step S2 with the target bending stiffness, and if the matching is satisfied K joint ≥ K req the matching is successful, and the joint design scheme is output. If not satisfied, adjust the joint structure parameters by increasing the bolt diameter, increasing the number of steel bars or selecting higher strength concrete; repeat step S2 after adjustment, and then re-verify until the matching condition is met.

2. The intelligent design method of the performance-based matching asymmetric combined joint of pipe section of pipe pushing according to claim 1, characterized in that: In step S1, a finite element model is established to solve the target bending moment required to be borne at the joint position by numerical simulation M req , the target bending stiffness is calculated according to formula (1) K req ; （1）， wherein, Theta allow The maximum rotation angle allowed for the joint is determined by the waterproofing level and the deformation control requirements of the pipe joint.

3. The intelligent design method of the performance-based matching asymmetric combined joint of pipe section of pipe pushing according to claim 2, characterized in that: The joint comprises a tenon pipe piece and a mortise pipe piece, which are connected inside and outside the pipe piece by a connecting piece; the connecting piece comprises at least one of an inclined bolt, a bent bolt, a C-shaped channel steel, an H-shaped channel steel and a short bolt.

4. The intelligent design method of the asymmetric combined joint of the pipe section of the pipe pushing based on performance matching according to claim 3, characterized in that: The asymmetric synergy coefficient values of different asymmetric combined joints are as follows: CHC-TSB combined joint, η = 0.60; CCC-TSB combined joint, η = 0.55; CB-TSB combined joint, η = 0.42; CB-CHC combined joint, η = 0.45; CCC-CHC combined joint, η = 0.40; In the TSB joint, the tenon pipe piece and the mortise pipe piece are connected by an inclined bolt; In the CCC joint, the tenon pipe piece and the mortise pipe piece are connected by two C-shaped channel steels to form a three-C-shaped steel-concrete joint; In the CHC joint, the tenon pipe piece and the mortise pipe piece are connected by a C-shaped channel steel and an H-shaped channel steel to form a double-C-shaped steel-concrete joint; In the CB joint, the tenon pipe piece and the mortise pipe piece are connected by two C-shaped channel steels and short bolts to form a channel steel-bolt joint.

5. The intelligent design method of the performance-based matching asymmetric combined joint of pipe section of pipe pushing according to claim 4, characterized in that: The bending stiffness of the bolt connection part in the joint is calculated by formula (3): （3）， wherein, E c , E b Econcrete, Ebolt are elastic modulus of concrete and bolt, respectively; I c Ic is a cross-sectional moment of inertia of a tenon tube piece / mortise tube piece, n b N is a number of bolts, A b As is a cross-sectional area of a single bolt, e D is a distance from a bolt to a neutral axis of a cross section; the bolt includes at least one of an inclined bolt and a short bolt. The bending stiffness of the channel steel connection part in the joint is calculated by formula (4): （4）， wherein, E steel , E s is the elastic modulus of C-shaped or H-shaped steel or concrete, I steel is the cross-sectional moment of inertia of C-shaped or H-shaped steel, n s , n steel are respectively the number of steel bars, channel steels, I s is the cross-sectional moment of inertia of a single steel bar; the channel steel includes at least one of C-shaped steel and H-shaped steel.

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