Pipe joint connecting structure suitable for large-section pipe jacking and bearing capacity design method

Abstract

The application discloses a pipe joint connecting structure and a bearing capacity design method suitable for large-section pipe jacking, which comprises multiple groups of plugs and multiple groups of sockets; the multiple groups of plugs are uniformly arranged at one end of a preceding pipe joint, and the multiple groups of sockets are uniformly arranged at one end of a subsequent pipe joint; the plugs and the sockets are respectively fixed at two ends of axial force transmission steel bars in the pipe joint; when the preceding pipe joint is spliced with the subsequent pipe joint, the plugs and the sockets are inserted and fixed; the axial force transmission steel bars, the plugs and the sockets in the buckle type connecting piece are arranged, no additional process is needed, and the bearing structure is clearly stressed; when the pipe joint is in a complex stratum and differential settlement and eccentric bending moments occur, the shear force is effectively transmitted to the pipe piece structure, the close contact of the two pipe joints is ensured, and the risk of groundwater infiltration from the open cracks is eliminated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground tunnel engineering, and particularly relates to a pipe joint connecting structure suitable for large-section pipe jacking and a bearing capacity design method. BACKGROUND

[0002] Under the background of rapid development of urban construction and rapid growth of population density, increasing the development and utilization of underground space has become an inevitable trend. Compared with open excavation and shield construction methods, pipe jacking method has the advantages of low comprehensive cost, small traffic interference and environmental friendliness, and is widely used in municipal comprehensive pipe gallery, subway station and other municipal engineering scenes in urban life circle. With the development of engineering technology and the increasing number of pipe jacking cases, it can be found that when the pipe jacking passes through complex strata, due to uneven torque distribution of pipe jacking head face, uneven settlement of foundation and other reasons, shear and fault deformation between pipe joints of rectangular pipe jacking is prone to occur, which further leads to waterproof failure at the joint of two pipe joints and crisis of structural safety.

[0003] In view of the above problems, in the practice of rectangular pipe jacking engineering, the commonly used F-shaped socket joint connecting structure (such as Chinese invention patent CN208845194) is to paste and install 1-2 chloroprene rubber on the tenon part of the subsequent pipe joint, and after inserting the steel sleeve ring at the tail of the preceding pipe joint, it is extruded by the outer steel sleeve ring to form the main waterproof structure during pipe jacking construction. After the pipe jacking construction is completed, the grouting hole is reserved, and the grouting hole is injected with slurry for secondary plugging, and the slurry becomes the second waterproof structure during operation after solidification. The joint connecting structure can rely on the strength of the outer steel sleeve ring to resist a certain fault deformation. In the conventional stratum, the deformation is not large, the steel sleeve ring is in the elastic stage, the deformation can be restored, the joint connecting structure will not be damaged, and the waterproof structure can still play a normal function. In complex strata, the pipe joint fault and torsional deformation increase, and the outer steel sleeve ring continues to rely on its own strength to resist deformation, which will lead to:

[0004] (1) The risk of waterproof structure failure is large: the traditional two pipe joints rely on the friction between the steel sleeve ring and the chloroprene rubber to resist tensile deformation, the tensile deformation friction between the two is small, the pipe joint is prone to fault and torsional deformation, which leads to uneven stress between the steel sleeve ring and the chloroprene rubber, and the formation of void in some areas, which cannot guarantee the close contact between the pipe joints, and has the risk of infiltration of underground water through the cracks;

[0005] (2) The bearing structure is complex, and it is difficult to check the actual bearing capacity of the joint structure.

[0006] In view of the above defects, the present inventors have finally obtained the present application after long-term research and practice. SUMMARY

[0007] The application aims to provide a pipe joint connecting structure and a bearing capacity design method suitable for large-section pipe jacking, and solve the problems of easy failure of the waterproof structure of the traditional joint connecting structure and difficult checking of the bearing capacity.

[0008] The application is to solve the above technical problems by the following technical scheme, and comprises a plurality of plug sets and a plurality of socket sets; the plurality of plug sets are uniformly arranged at one end of a preceding pipe joint, the plurality of socket sets are uniformly arranged at one end of a subsequent pipe joint, the plug sets and the socket sets are respectively fixed at both ends of the axial force transmission steel bars in the pipe joint, and the plug sets and the socket sets are fixed by plug-in connection when the preceding pipe joint and the subsequent pipe joint are spliced.

[0009] Preferably, the plug set comprises an anchoring support, a connecting rod and a clamping block; the anchoring support is fixedly connected with one end of the axial force transmission steel bar, the connecting rod is screwed with the anchoring support, and the clamping block is fixed at the end of the connecting rod through the connecting block; and the clamping block is in the shape of a circular truncated cone.

[0010] Preferably, the socket set comprises a bolt fixing cylinder, an anchoring sleeve, a buckle and a spring; the anchoring sleeve is fixedly connected with one end of the axial force transmission steel bar, the spring, the buckle and the bolt fixing cylinder are sequentially arranged in the anchoring sleeve, the bolt fixing cylinder is screwed in the inner hole of the anchoring sleeve, and the buckle is adaptively connected with the clamping block.

[0011] Preferably, the connecting rod has a tapered surface on the side away from the anchoring support, the inner hole of the anchoring sleeve is a tapered hole, and the tapered surface is adaptively connected with the tapered hole.

[0012] Preferably, the outside of the slot end of the preceding pipe joint is fixed with a slot outside steel sleeve ring, the slot outside steel sleeve ring extends transversely to the outside of the tenon end of the subsequent pipe joint, the slot outside steel sleeve ring and the outside of the subsequent pipe joint are provided with a hawk mouth sealing rubber strip, the inside of the slot end of the preceding pipe joint is fixed with a slot inside steel sleeve ring, the outside of the tenon of the subsequent pipe joint is fixed with a tenon outside steel sleeve ring, the inside of the tenon of the subsequent pipe joint is fixed with a tenon inside steel sleeve ring, and the slot outside steel sleeve ring, the slot inside steel sleeve ring, the tenon outside steel sleeve ring and the tenon inside steel sleeve ring are all fixed with a cable-stayed anchoring steel bar in the pipe joint.

[0013] Preferably, a plywood is arranged between the preceding pipe joint and the subsequent pipe joint, and the inside of the plywood is filled with sealing glue.

[0014] The application further provides a bearing capacity design method based on the pipe joint connecting structure suitable for large-section pipe jacking, which comprises the following steps:

[0015] Step one: calculation of the load effect value under the bearing capacity limit state:

[0016] Based on the vertical settlement and the torsional deformation control index of the pipe joint, the working condition is established, the internal force of the pipe piece structure is analyzed, and the load effect value S of the action combination under the limit state of the joint bearing capacity is obtained Qi , which is decomposed into: the torque load S of the barycenter and the geometric center of the section coinciding, the torque load S of the direction parallel to the jacking direction Q,T And the shear load S Q,v , and the direction of the shear load S Q,v is parallel to the direction of gravity;

[0017] Step two: calculate the design value of the joint bearing capacity:

[0018] After the plug and the socket are connected, under the action of the torque load S T and the shear load S v , the joint mainly bears the shear force, and the maximum shear force value that the connecting rod can bear is taken as the design value of the resistance:

[0019]

[0020] In the formula, f v represents the shear strength design value of the bolt, d c represents the diameter of the selected connecting rod;

[0021] Step three: strength check:

[0022] Along the center line of the section, there are N groups of plugs and sockets, the shear force on each group of plugs is the resultant force of the force F' perpendicular to the plug-barycenter connecting line and the force F'' always keeping vertical, and the size of the resultant force is related to the position of the plug, at this time, the following should be met:

[0023]

[0024] Among them,

[0025]

[0026]

[0027] In the formula, θ i represents the angle between the plug-barycenter connecting line and the horizontal direction, r i represents the straight-line distance from the plug to the barycenter, i.e. the force arm, γ0 represents the structure importance coefficient, generally ≥1.0, γ Q,T , γ Q,v are load partial coefficients.

[0028] Compared with the prior art, the beneficial effects of the present application are:

[0029] Compared to the traditional F-type socket joint, this invention, by setting axial force transmission steel bars and plugs and sockets in snap-fit ​​connectors, eliminates the need for additional procedures and ensures clear stress on the load-bearing structure. When the pipe section is in a complex stratum and experiences differential settlement and eccentric bending moment, it effectively transfers the shear force to the segment structure, ensuring close contact between the two pipe sections and eliminating the risk of groundwater infiltration through open cracks. Attached Figure Description

[0030] Figure 1 This is a front view structural diagram of the pipe section in this invention;

[0031] Figure 2 This is a schematic diagram of the cross-sectional structure of the rectangular cross-section jacking pipe section in this invention;

[0032] Figure 3 This is a schematic diagram of the cross-sectional structure of the circular cross-section jacking pipe section in this invention;

[0033] Figure 4 This is a partial structural diagram showing the connection between the tenon end and the groove end of two adjacent pipe sections.

[0034] Figure 5 This is a structural diagram of a snap-fit ​​connector;

[0035] Figure 6 This is a schematic diagram of the snap-fit ​​connector structure.

[0036] The numbers in the diagram represent:

[0037] 1-1: Preliminary pipe section; 1-2: Subsequent pipe section; 2-1: Steel collar outside the groove; 2-2: Steel collar inside the groove; 3-1: Steel collar outside the tenon; 3-2: Steel collar inside the tenon; 4: Diagonal anchoring steel bar; 5: Eagle beak sealing rubber strip; 6: Axial force transmission steel bar; 7: Sealant; 8: Plywood; 9: Plug; 9-1: Anchoring support; 9-2: Connecting rod; 9-3: Clip; 10: Socket; 10-1: Bolting cylinder; 10-2: Anchoring sleeve; 10-3: Buckle; 10-4: Spring; 11: First grouting hole; 12: Second grouting hole. Detailed Implementation

[0038] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0039] Example 1

[0040] This embodiment provides a technical solution: a semi-rigid rectangular large-section pipe jacking joint suitable for complex strata, such as... Figure 4 As shown, this joint is installed on two pipe sections that are joined end to end. The two pipe sections are the first pipe section 1-1 and the subsequent pipe section 1-2, with the two ends of the pipe sections being the tenon end and the groove end, respectively.

[0041] The slot end of the preceding pipe section 1-1 is fixed with a slot outer steel sleeve ring 2-1 and a slot inner steel sleeve ring 2-2, the slot outer steel sleeve ring 2-1 and the slot inner steel sleeve ring 2-2 are respectively located at the outer side and the inner side of the slot end, the slot outer steel sleeve ring 2-1 extends transversely to the tenon end of the subsequent pipe section 1-2; the tenon end of the subsequent pipe section 1-2 is fixed with a tenon outer steel sleeve ring 3-1 and a tenon inner steel sleeve ring 3-2, the tenon outer steel sleeve ring 3-1 and the tenon inner steel sleeve ring 3-2 are respectively fixed at the outer side and the inner side of the tenon end.

[0042] The plurality of steel sleeve rings are fixed with the inclined anchoring steel bars 4 located in the pipe section, the inclined anchoring steel bars 4 are uniformly distributed in the pipe section, the tenon outer side is provided with the hawk mouth sealing rubber strip 5 surrounding the tenon outer side, and the first grouting hole 11 and the second grouting hole 12 are further arranged in the concrete structure of the head of the subsequent pipe section 1-2.

[0043] In order to protect the contact surface of the adjacent two pipe sections, the plywood 12 is further arranged between the two pipe sections, and the plywood 12 plays a role of transmitting the jacking load and coordinating the deformation.

[0044] In the jacking construction stage, the tenon of the subsequent pipe section 1-2 is inserted into the tail slot of the preceding pipe section 1-1 under the action of the jacking force of the pipe jacking machine, the slot outer steel sleeve ring 2-1 and the hawk mouth sealing rubber strip 5 are tightly pressed to form the first waterproof structure; after the construction is completed, the waterproof slurry is injected into the pores between the pipe section and the soil through the first grouting hole 11 and the second grouting hole 12 to form the second waterproof structure; additionally, the sealant 9 is filled in the gap formed in the internal space of the pipe section due to the deformation of the pipe section after the construction is completed, and the sealant 9 is solidified to form the third waterproof measure, and the sealant 9 is a high modulus sealant.

[0045] Embodiment two

[0046] The embodiment is further optimized on the basis of the above-mentioned embodiment, and the same parts as the foregoing technical solutions will not be described here again, such as Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 and Figure 6 In order to better realize the present application, the following setting mode is particularly adopted: in order to improve the waterproofness and reliability of the joint of the adjacent two pipe sections in the complex stratum, the axial force transmission steel bars 6 are further arranged in the pipe section structure of the pipe section in the embodiment, the axial force transmission steel bars 6 are uniformly distributed in the pipe section, and the plug 9 and the socket 10 are respectively arranged at the two ends of the axial force transmission steel bars 6, the plug 9 and the socket 10 are combined to form the buckle type connecting piece, and the buckle type connecting piece is used for connecting the axial force transmission steel bars 6 in the adjacent two pipe sections.

[0047] The plug 9 comprises an anchoring support 9-1, a connecting rod 9-2 and a clamping block 9-3. In the pipe segment manufacturing stage, one end of the axial force transmission steel bar 6 is connected with the anchoring support 9-1 at the head of the pipe segment, and the other end is connected with the socket 10 at the tail of the pipe segment, and is embedded in the pipe segment. The anchoring support 9-1 is welded and fixed with the axial force transmission steel bar 6. The connecting rod 9-2 is connected with the anchoring support 9-1 in the form of threaded rotation. The connecting rod 9-2 has a threaded part for screwing with the anchoring support 9-1. The side of the connecting rod 9-2 away from the anchoring support 9-1 has a tapered surface. The end of the connecting rod 9-2 is fixed with a circular truncated cone-shaped clamping block 9-3 through a connecting block.

[0048] The socket 10 comprises a fastening cylinder 10-1, an anchoring sleeve 10-2, a buckle 10-3 and a spring 10-4. The anchoring sleeve 10-2 is welded and fixed with the axial force transmission steel bar 6. The anchoring sleeve 10-2 is in a cylindrical structure. The fastening cylinder 10-1 is screwed into the inner hole of the anchoring sleeve 10-2. The fastening cylinder 10-1 is an external threaded cylinder structure, and the inner hole thereof is a tapered hole adapted to the matching part of the connecting rod 9-2, so as to eliminate the error in butt joint and ensure the sealing property after butt joint. The spring 10-4 and the buckle 10-3 are arranged in the fastening cylinder 10-1. The buckle 10-3 is adapted to be clamped with the clamping block 9-3. The buckle 10-3 will move outwardly due to the elastic force of the spring 10-4, and the fastening cylinder 10-1 will limit the buckle 10-3 from being separated from the anchoring sleeve 10-2.

[0049] In the jacking construction stage, when the tenon of the subsequent pipe segment 1-2 is inserted into the notch of the preceding pipe segment 1-1, the clamping block 9-3 extends into the fastening cylinder 10-1 and pushes the buckle 10-3 in the compressed state to move inwardly. The clamping opening part of the buckle 10-3 is made of a metal material with elasticity. When the buckle 10-3 is contracted inwardly to a certain position, the clamping opening will be opened to clamp the clamping block 9-3 under the pushing force of the spring 10-4, as shown in Figure 6 Thereafter, when the pipe segment is subjected to tension and the contact surface has a tendency to open, the tension can be transferred to the axial force transmission steel bar 6 through the structure shown in the figure, so as to limit the opening of the pipe segment contact surface of the pipe segment and ensure the close contact between the preceding and subsequent pipe segments.

[0050] Embodiment Three

[0051] The embodiment provides a technical scheme: a bearing capacity design method of a semi-rigid rectangular large-section pipe joint suitable for complex strata, as shown in Figure 2 and Figure 3 The method comprises the following steps:

[0052] Step one: calculation of load effect value under bearing capacity limit state:

[0053] Based on the vertical settlement and the torsional deformation control index of the pipe joint, the working condition is established, the internal force of the pipe piece structure is analyzed, and the load effect value S of the action combination under the limit state of joint bearing capacity is obtained Qi , which is decomposed into: the torque load S of the barycenter and the geometric center of the section coinciding, the direction of the torque load S parallel to the jacking direction Q,T And the shear load S Q,v , and the direction of the shear load S Q,v is parallel to the direction of gravity.

[0054] Step two: calculate the resistance design value of the joint bearing capacity:

[0055] In the pipe joint scheme involved in the application, after the plug and the socket are connected, under the action of the torque load S T And the shear load S v , the joint mainly bears shear force, and the maximum shear force value that the connecting rod can bear is taken as the resistance design value:

[0056]

[0057] In the formula, f v Indicates the shear strength design value of the bolt, d c Indicates the diameter of the selected connecting rod.

[0058] Step three: strength check:

[0059] Along the center line of the section, N groups of plugs and sockets are uniformly arranged, the shear force on each group of plugs is the resultant force of the force F' perpendicular to the plug-barycenter connecting line and the force F'' always keeping vertical, the size of the resultant force is related to the position of the plug, at this time, the following should be met:

[0060]

[0061] Among them,

[0062]

[0063]

[0064] In the formula, θ i Indicates the angle between the plug-barycenter connecting line and the horizontal direction, r i Indicates the straight-line distance from the plug to the barycenter, i.e. the force arm, γ0 indicates the structural importance coefficient, generally ≥1.0, γ Q,T , γ Q,v Are load partial coefficients.

[0065] The above descriptions are only the preferable embodiments of the present application, which are only illustrative but not restrictive. It is understood by those skilled in the art that many changes, modifications, even equivalences can be made to the present application within the spirit and scope defined by the claims of the present application, and all of them will fall into the protection scope of the present application.

Claims

1. A method for designing the bearing capacity of a pipe joint structure suitable for large-section pipe jacking, characterized in that, The pipe joint connecting structure comprises multiple groups of plugs and multiple groups of sockets; the multiple groups of plugs are uniformly arranged at one end of a preceding pipe joint, the multiple groups of sockets are uniformly arranged at one end of a subsequent pipe joint, the plugs and the sockets are respectively fixed at both ends of the axial force transmission steel bars inside the pipe joints, and the plugs and the sockets are inserted and fixed when the preceding pipe joint is spliced with the subsequent pipe joint; The bearing capacity design method comprises the following steps: Step one: load effect value calculation under the limit state of bearing capacity: Based on the control index of vertical settlement and torsional deformation of pipe joint, the working conditions are established, and the internal force of pipe segment structure is analyzed to obtain the load effect value S of action combination under the limit state of joint bearing capacity Qi , which is decomposed into: the torque load S with the barycenter and the geometric center of the section coinciding, the torque load S with the jacking direction parallel Q,T , and the shear load S Q,v , and the direction of the shear load S Q,v is parallel to the direction of gravity. Step two: calculation of joint bearing capacity resistance design value: After the plug and the socket are connected, the joint bears the torque load S T and the shear load S v Under the action of the shear load S, the joint mainly bears the shear force, and the maximum shear force value that the connecting rod can bear is taken as the resistance design value. wherein f v represents the shear strength design value of the bolt, d c represents the diameter of the selected connecting rod; Step three: strength check: N groups of plugs and sockets are uniformly arranged along the section centerline, the shear force on each group of plugs is the resultant force of the force F' perpendicular to the plug-center line and the force F" always keeping vertical, the resultant force size is related to the plug position, at this time, the following conditions should be met: Wherein, In the formula, θ i represents the angle between the plug-centroid connecting line and the horizontal direction, r i represents the straight-line distance from the plug to the centroid, i.e. the force arm, γ0represents a structure importance coefficient, generally ≥ 1.0, γ Q,T , γ Q,v is a load partial coefficient.

2. The method for designing the carrying capacity of the pipe joint structure suitable for large-section pipe jacking according to claim 1, characterized in that, The plug comprises an anchoring support, a connecting rod and a clamping block; one end of the anchoring support is fixedly connected with the axial force transmission steel bar, the connecting rod is screwed with the anchoring support, and the clamping block is fixed to the end of the connecting rod through the connecting block; the clamping block is a circular truncated cone.

3. The method for designing the carrying capacity of the pipe joint structure suitable for large-section pipe jacking according to claim 2, characterized in that, The socket comprises a bolting cylinder, an anchoring sleeve, a buckle and a spring; one end of the anchoring sleeve is fixedly connected with the axial force transmission steel bar, the spring, the buckle and the bolting cylinder are sequentially arranged in the anchoring sleeve, the bolting cylinder is screwed in the inner hole of the anchoring sleeve, and the buckle is adaptively connected with the clamping block.

4. The method for designing the carrying capacity of the pipe joint structure of the pipe jacking suitable for large cross-section according to claim 3, characterized in that, The side of the connecting rod away from the anchoring support has a tapered surface, the inner hole of the anchoring sleeve is a tapered hole, and the tapered surface is adaptively connected with the tapered hole.

5. The method for designing the carrying capacity of the pipe joint structure of the pipe section suitable for the large-section pipe jacking according to claim 1, characterized in that, The outside of the slot end of the preceding pipe joint is fixedly connected with a slot outside steel sleeve ring, the slot outside steel sleeve ring extends transversely to the outside of the tenon end of the subsequent pipe joint, the slot outside steel sleeve ring and the outside of the subsequent pipe joint are provided with a hawk mouth sealing rubber strip, the inside of the slot end of the preceding pipe joint is fixedly connected with a slot inside steel sleeve ring, the outside of the tenon of the subsequent pipe joint is fixedly connected with a tenon outside steel sleeve ring, the inside of the tenon of the subsequent pipe joint is fixedly connected with a tenon inside steel sleeve ring, and the slot outside steel sleeve ring, the slot inside steel sleeve ring, the tenon outside steel sleeve ring and the tenon inside steel sleeve ring are all fixedly connected with the inclined cable anchoring steel bars inside the pipe joints.

6. The method for designing the carrying capacity of the pipe joint structure of the pipe section suitable for large-section pipe jacking according to claim 1, characterized in that, The preceding pipe joint and the subsequent pipe joint are provided with a plywood, and the inside of the plywood is filled with sealing glue.

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