Counter-force structure construction method for pipe roof jacking

Abstract

The invention belongs to the technical field of underground passage construction, and particularly relates to a counter-force structure construction method for pipe roof jacking, which comprises the following steps of: driving support piles at two ends of a corresponding side line behind a working well to form corresponding counter-force columns; steel sheet piles are arranged between the two counter-force columns along the corresponding side line behind the working well in a driving mode, counter-force steel plates are installed on the counter-force walls, and grouting pipes penetrate through the counter-force steel plates, then stretch into the rear undisturbed soil from gaps between the steel sheet piles and are fixedly connected with the rear undisturbed soil into a whole through grouting. Through the synergistic effect of the counter-force column formed by the supporting piles and the undisturbed soil subjected to grouting consolidation, a composite counter-force system is constructed, and the bearing capacity and stability of the counter-force structure are effectively improved. The protection piles and the supporting piles are meshed with each other to form a closed or semi-closed structure, the stability of the soil body around the working well is further enhanced by matching with the reinforcing effect of the top beams and the inclined struts, and collapse or displacement of the soil body in the jacking process is avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of underground passage construction, and particularly relates to a counterforce structure construction method for pipe curtain jacking. BACKGROUND

[0002] In underground engineering construction, pipe curtain support technology is widely used in underground passage excavation engineering under complex geological conditions such as soft soil area and water-rich stratum due to its good soil reinforcement, waterproofing and bearing capacity. In the process of pipe curtain jacking construction, reliable counterforce structure is needed to provide jacking counterforce to ensure that the pipe curtain can be accurately and stably jacked into the preset position. The existing pipe curtain jacking counterforce structure mostly uses cast-in-place reinforced concrete back wall or steel support structure. The back wall has problems such as long construction period, large material consumption and poor adaptability. The support strength of steel support is limited. For example, the construction method disclosed in the announcement No. CN113685202B needs to set a relatively long length of steel support when working in soft clay, which greatly interferes with the construction. In addition, the soil stability of the underground passage to be constructed under soft clay geology is poor, and the jacking of the pipe curtain is prone to deviation during the construction process, which makes the later excavation more difficult.

[0003] Therefore, it is necessary to provide an improved technical solution for the above-mentioned deficiencies of the prior art. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art. The present application provides a counterforce structure construction method for pipe curtain jacking.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions: A counterforce structure construction method for pipe curtain jacking, the construction method comprising: Step S1, measuring and laying out the working well, setting up protection piles along the corresponding lines on both sides and in front of the working well, and any two adjacent protection piles are engaged with each other to form a protection curtain wall; Step S2, setting up support piles at both ends of the corresponding line behind the working well, and a plurality of support piles are engaged with each other to form counterforce columns corresponding to the two sides of the pipe curtain of the underground passage to be excavated; Between the two counterforce columns, steel sheet piles are set up along the corresponding line behind the working well, and a gap is left between any two adjacent steel sheet piles; Step S3, excavating by excavating equipment, excavating to the corresponding pipe curtain elevation above the underground passage to be excavated, installing counterforce steel plates on the counterforce wall, inserting the grouting pipe into the original soil behind the gap between the steel sheet piles through the counterforce steel plates, and solidifying the grouting pipe with the original soil behind through grouting; Step S4, after the insertion hole is drilled on the protective curtain wall, the pipe curtain jacking is performed, and after the upper pipe curtain jacking is completed, the steel sheet pile is removed and the working well excavation is continued; Step S5, during the working well excavation, the pipe curtain on both sides of the to-be-excavated underground passage is drilled according to the excavation progress, and the pipe curtain on both sides is jacked with the support column as the support point; Step S6, after the working well is excavated to the preset bottom surface, the steel sheet pile is formed again along the line corresponding to the rear of the working well to form a counterforce wall, the insertion hole corresponding to the bottom pipe curtain of the to-be-excavated underground passage is drilled on the protective curtain wall, and then the pipe curtain jacking is performed; Step S7, after the bottom pipe curtain construction is completed, the counterforce column is removed, and the working well bottom surface is concreted and hardened.

[0006] Preferably, in step S1, a corbel is poured above the protective pile, and an inclined brace is arranged between the corbel on both sides and in front of the working well, and the inclined braces on both sides of the working well are symmetrically distributed about the working well center line.

[0007] Preferably, a plurality of pipe curtains are arranged in parallel along the outer periphery of the to-be-excavated underground passage, a plurality of grouting anchor rods located in the middle of the to-be-excavated underground passage are arranged on the protective curtain wall according to the working well excavation progress, the grouting anchor rods extend parallel to the pipe curtains, and the soil inside the to-be-excavated underground passage is integrated with the corresponding protective curtain wall through grouting of the grouting anchor rods.

[0008] Preferably, the length of the grouting anchor rod is not less than one third of the length of the to-be-excavated underground passage.

[0009] Preferably, the lower ends of the protective piles and the support piles are located below the to-be-excavated underground passage by 4-5m.

[0010] Preferably, the support piles are all bored piles, and the support piles are broken down with the working well excavation progress.

[0011] Preferably, during the working well excavation, the original soil behind the counterforce wall is excavated synchronously, the excavation line of the original soil behind the counterforce wall is at least 1m higher than the working well excavation line, and the original soil 2m behind the counterforce wall is sloped to form a slope surface.

[0012] Preferably, the length of the grouting pipe is 2m.

[0013] Preferably, after the bottom pipe curtain construction is completed, the original soil behind the counterforce wall is excavated to the working well bottom surface level.

[0014] Beneficial effect: the counterforce column formed by the support pile cooperates with the original soil after grouting consolidation to build a composite counterforce system, effectively improving the bearing capacity and stability of the counterforce structure. The protective pile and the support pile are interlocked to form a closed or semi-closed structure, which, in combination with the reinforcement effect of the crown beam and the inclined brace, further enhances the stability of the soil around the working well, avoiding soil collapse or displacement during jacking. BRIEF DESCRIPTION OF DRAWINGS

[0015] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation on the application. Among them: Figure 1 A top view of the counterforce structure in the specific embodiment provided by the present application; Figure 2 A construction schematic diagram of the pipe roof above the underground passage to be excavated in the specific embodiment provided by the present application; Figure 3 A construction schematic diagram of the pipe roof below the underground passage to be excavated in the specific embodiment provided by the present application.

[0016] In the figure: 1, protective pile; 2, crown beam; 3, inclined brace; 4, underground passage to be excavated; 5, support pile; 6, counterforce steel plate; 7, steel sheet pile; 8, slope surface; 9, pipe roof; 10, grouting anchor rod; 11, grouting pipe. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present application belong to the scope of protection of the present application.

[0018] In the description of the present application, the orientations or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application, and do not require the present application to be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. The terms "connected", "connected" used in the present application should be understood broadly, for example, can be fixed connection, can also be detachable connection; can be directly connected, can also be indirectly connected through intermediate parts, and the specific meaning of the above terms can be understood by those skilled in the art according to the specific circumstances.

[0019] The application will be described in detail below with reference to the drawings and in conjunction with the embodiments. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0020] As Figure 1 , 2 , 3, a counterforce structure construction method for pipe roof jacking, the construction method comprises the following steps: S1, measuring and lofting the working well, and setting up protection piles 1 along the corresponding lines on both sides and in front of the working well, the protection piles 1 being mixing piles, any two adjacent protection piles 1 being engaged with each other to form a protection curtain wall, which can be used as a waterproof curtain wall while improving the structural strength by mutual engagement, so as to avoid external groundwater from seeping into the working well.

[0021] S2, setting up support piles 5 at both ends of the corresponding lines at the rear of the working well, a plurality of support piles 5 being engaged with each other, generally 2-3 can be used, the support piles 5 being bored piles with a steel cage below and pouring concrete, the lower end of the support pile 5 being located 4-5 m below the pipe roof 9 elevation below the to-be-excavated underground passage 4, having high strength, so as to form counterforce columns corresponding to the pipe roof 9 on both sides of the to-be-excavated underground passage 4, which can be used as support components for pipe roof 9 jacking along with the working well excavation progress, and the support pile 5 is broken down along with the working well excavation progress.

[0022] Between the two counterforce columns, steel sheet piles 7 are set up along the corresponding lines at the rear of the working well, a gap being left between any two adjacent steel sheet piles 7, the gap between the steel sheet piles 7 being not greater than one half of the width of the steel sheet pile 7, the gap between the steel sheet piles 7 being used as a channel for inserting the grouting pipe 11, and the construction quantity of the steel sheet piles 7 can be reduced, the construction disturbance to the surrounding of the working well can be reduced, and the construction efficiency is improved.

[0023] S3, excavation is carried out by excavating equipment such as excavators, and foundation pit support is done well during the excavation process to avoid soil collapse. After the working well is excavated to the corresponding pipe roof 9 elevation above the to-be-excavated underground passage 4, the excavation is stopped, the counterforce steel sheet 6 is installed on the counterforce wall, and the guide rail corresponding to the pipe roof 9 is laid, the counterforce steel sheet 6 is provided with perforations, the grouting pipe 11 is inserted through the counterforce steel sheet 6, and then the grouting pipe 11 extends into the rear undisturbed soil from the gap between the steel sheet piles 7, and is consolidated with the rear undisturbed soil by grouting, so as to form a composite counterforce system by the synergistic effect of the counterforce columns formed by the support piles 5 and the consolidated undisturbed soil after grouting, effectively improving the bearing capacity and stability of the counterforce structure. In the embodiment, the lower end of the steel sheet pile 7 can be set at 2 m below the working well excavation surface, which reduces the construction difficulty and construction disturbance.

[0024] Step S4, install the jacking device and guide rail, drill the insertion hole on the protective curtain wall, and then jack the pipe curtain 9. The insertion hole can guide the pipe curtain 9 and ensure the accuracy of the pipe curtain 9 jacking. After the upper pipe curtain 9 jacking is completed, the steel sheet pile 7 and the counterforce steel plate 6 are removed, and the working well excavation continues. Step S5, during the working well excavation, the insertion hole corresponding to the pipe curtain 9 on both sides of the to-be-excavated underground passage 4 is supported by the support column, and the pipe curtain 9 on both sides is jacked. During the working well excavation, the insertion hole corresponding to the pipe curtain 9 on both sides of the to-be-excavated underground passage 4 is supported by the support column, and the pipe curtain 9 on both sides is jacked. At the same time, the original soil behind the counterforce wall is excavated synchronously, and the excavation line of the original soil behind the counterforce wall is at least 1m higher than the working well excavation line, and the original soil 2m behind the counterforce wall is sloped to form a slope 8. A plurality of pipe curtains 9 are arranged in parallel along the outer periphery of the to-be-excavated underground passage 4. According to the working well excavation progress, a plurality of grouting anchor rods 10 are arranged on the protective curtain wall and located in the middle of the to-be-excavated underground passage 4. The grouting anchor rod 10 extends parallel to the pipe curtain 9. The grouting anchor rod 10 is used for grouting, so that the soil inside the to-be-excavated underground passage 4 is integrated with the corresponding protective curtain wall. The length of the grouting anchor rod 10 is not less than one third of the length of the to-be-excavated underground passage 4. The counterforce steel plate 6 can be constructed in stages according to the working well excavation progress, so as to adapt to the jacking needs of the upper and lower pipe curtains 9, and is suitable for underground passage construction of different depths and different cross-sectional sizes.

[0025] Step S6, continue to excavate the working well, and jack the pipe curtain 9 on both sides during the excavation process. After the working well is excavated to the preset bottom surface, the steel sheet pile 7 is arranged along the corresponding edge line behind the working well to form a counterforce wall. Similarly, the jacking device and guide rail are installed, the insertion hole corresponding to the pipe curtain 9 at the bottom of the to-be-excavated underground passage 4 is drilled on the protective curtain wall, and then the pipe curtain 9 is jacked. The insertion hole is used to limit the pipe curtain, and a limiting mechanism is not needed during jacking. The grouting anchor rod is used for grouting the original soil inside the to-be-excavated underground passage, so as to ensure the stability of the soil inside the to-be-excavated underground passage and provide guarantee for the installation quality of the pipe curtain. Step S7, after the bottom pipe curtain 9 construction is completed, the corresponding counterforce column and counterforce steel plate 6 are removed, then the bottom surface of the working well is leveled, and the bottom surface of the working well is poured and hardened with concrete. The concrete strength grade is determined according to the design requirements, and is generally not less than C30. After pouring, maintenance is carried out for not less than 7 days to ensure the bearing capacity of the bottom surface of the working well.

[0026] At the same time, the original soil behind the working well is excavated to the working well bottom surface elevation.

[0027] In an optional embodiment, after the construction of the protective pile 1 is completed, a corbel 2 is poured above the protective pile 1, the corbel 2 is made of reinforced concrete structure, the width of the corbel 2 is matched with the protective pile 1, the two are integrally poured, and after the pouring is completed, the inclined struts 3 are arranged between the corbel 2 on both sides of the working well and the front of the working well, the inclined struts 3 are symmetrically distributed about the center line of the working well, which further enhances the overall stability of the protective curtain wall, so as to improve the structural strength of the working well.

[0028] A plurality of pipe curtains 9 are arranged in parallel along the outer periphery of the underground passage 4 to be excavated, so as to protect the underground passage to be excavated. According to the excavation progress of the working well, a plurality of grouting anchor rods 10 located in the middle of the underground passage to be excavated 4 are arranged on the protective curtain wall, the grouting anchor rods 10 extend parallel to the pipe curtains 9, the grouting anchor rods 10 are arranged parallel to the extension direction of the pipe curtains 9, and the length of the grouting anchor rods 10 is not less than one third of the length of the underground passage to be excavated 4. The grouting is performed through the grouting anchor rods 10, so that the soil inside the underground passage to be excavated 4 is consolidated with the corresponding protective curtain wall, the stability and bearing capacity of the soil are enhanced, the protective curtain wall in the middle does not need to be lifted out during the construction process, the soil in front can be protected by the protective curtain wall, and the pipe curtains 9 are limited through the insertion holes in the protective curtain wall, so as to avoid the deviation of the pipe curtains 9.

[0029] The lower ends of the protective piles 1 and the support piles 5 are located below the pipe curtains 9 below the underground passage 4 to be excavated by 4-5 m, so as to ensure the anti-overturning and bearing capacity of the protective piles 1.

[0030] During the excavation of the working well, the undisturbed soil behind the counterfort wall is excavated synchronously, the excavation line of the undisturbed soil behind the counterfort wall is controlled to be at least 1 m higher than the excavation line of the working well, and the undisturbed soil 2 m behind the counterfort wall is graded to form a slope surface 8. The slope of the slope surface 8 is determined according to the geological conditions, and is generally 1:0.5-1:1, so as to ensure the stability of the soil behind the counterfort wall.

[0031] The pipe curtain 9 jacking counterforce structure construction method of the present application constructs the counterforce structure in stages, fully utilizes the bearing potential of the undisturbed soil, realizes the rapid construction and stable bearing of the counterforce structure, effectively solves many problems existing in the traditional counterforce structure, improves the efficiency and safety of the pipe curtain 9 jacking construction, and has a wide application prospect.

[0032] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application is within the protection scope of the claims of the present application.

Claims

1. A counter-force structure construction method for pipe-roof jacking, characterized in that, The construction method comprises: Step S1, measuring and lofting the working well, and setting up protection piles along the corresponding side lines on both sides and in front of the working well, and any two adjacent protection piles are engaged with each other to form a protection curtain wall; Step S2, setting up support piles at both ends of the corresponding side line at the rear of the working well, and a plurality of support piles are engaged with each other to form counterforce columns corresponding to the two sides of the pipe curtain of the underground passage to be excavated; Between the two counterforce columns, steel sheet piles are set up along the corresponding side line at the rear of the working well, and a gap is left between any two adjacent steel sheet piles; Step S3, excavating by an excavating device until the corresponding pipe curtain elevation of the underground passage to be excavated, and then installing counterforce steel plates on the counterforce wall, and making a grouting pipe pass through the counterforce steel plates and extend into the original soil at the rear from the gap between the steel sheet piles, and being consolidated with the original soil at the rear by grouting; Step S4, installing a jacking device, drilling insertion holes on the protection curtain wall, and then jacking the pipe curtain, and removing the steel sheet piles after the upper pipe curtain is jacked, and continuing to excavate the working well; Step S5, during the excavation of the working well, drilling holes in the pipe curtain on both sides of the underground passage to be excavated according to the excavation progress, and jacking the pipe curtain on both sides as the support point; Step S6, after the working well is excavated to the preset bottom surface, the steel sheet piles are set up again along the corresponding side line at the rear of the working well to form a counterforce wall, and a jacking device is installed, insertion holes corresponding to the bottom pipe curtain of the underground passage to be excavated are drilled on the protection curtain wall, and the pipe curtain is jacked; Step S7, after the bottom pipe curtain construction is completed, the counterforce columns are removed, and the bottom surface of the working well is poured with concrete and hardened.

2. The counter-force structure construction method of pipe-roof jacking according to claim 1, characterized in that, In step S1, a corbel is poured above the protection piles, and diagonal braces are arranged between the corbel on both sides and in front of the working well, and the diagonal braces on both sides of the working well are symmetrically distributed about the center line of the working well.

3. The counter-force structure construction method of pipe-roof jacking according to claim 1, characterized in that, A plurality of pipe curtains are arranged in parallel along the periphery of the underground passage to be excavated, a plurality of grouting anchor rods are arranged on the protection curtain wall at the middle part of the underground passage to be excavated according to the excavation progress of the working well, the grouting anchor rods extend parallel to the pipe curtains, and the soil inside the underground passage to be excavated is consolidated with the corresponding protection curtain wall by grouting through the grouting anchor rods.

4. The counter-force structure construction method of pipe-roof jacking according to claim 3, characterized in that, The length of the grouting anchor rod is not less than one third of the length of the underground passage to be excavated.

5. The counter-force structure construction method of pipe-roof jacking according to claim 1, characterized in that, The lower ends of the protection piles and the support piles are located below the pipe curtain elevation of the underground passage to be excavated by 4-5m.

6. The counter-force structure construction method of pipe-roof jacking according to claim 1, wherein, The support piles are all bored piles, and the support piles are broken down downward along with the excavation progress of the working well.

7. The counter-force structure construction method of pipe-roof jacking according to claim 1, wherein, During the excavation of the working well, the original soil behind the counterforce wall is excavated synchronously, the excavation line of the original soil behind the counterforce wall is at least 1m higher than the excavation line of the working well, and the original soil 2m behind the counterforce wall is graded to form a slope surface.

8. The counter-force structure construction method of pipe-roof jacking according to claim 7, characterized in that, The length of the grouting pipe is 2m.

9. The counter-force structure construction method of pipe-roof jacking according to claim 7, characterized in that, After the bottom pipe curtain construction is completed, the original soil behind is excavated to the bottom surface elevation of the working well.

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