A trenchless jacking pipe construction method crossing rock strata

Abstract

The application provides a trenchless jacking pipe construction method crossing rock strata, which comprises the following steps: establishing a construction control network, excavating a working well, installing a back wall, installing a guide rail in the working well, excavating a pilot hole, laying a guide rail in the pilot hole, extending the jacking pipe, grouting the pipe, and removing the jacking pipe. The application does not need to use a jacking pipe machine for construction, meets the small-distance rock strata jacking pipe construction, has strong adaptability to the jacking pipe section, slope and trend, has low construction cost, controllable construction period, 1m / d of daily tunneling length, small stratum deformation, good excavation contour control, controllable pipe joint installation quality, and high construction safety.

Description

Technical Field

[0001] This invention relates to the field of pipe jacking construction technology, specifically a trenchless pipe jacking construction method for penetrating rock strata. Background Technology

[0002] Trenchless engineering technology has completely solved the problems of damage to urban buildings and traffic congestion caused by pipeline laying, and its advantages are evident in stabilizing soil layers and protecting the environment. Pipe jacking is a type of trenchless construction technology. Commonly used pipe jacking is divided into three types according to different principles: air pressure balance, slurry balance, and earth pressure balance. The appropriate pipe jacking method is selected according to different geological conditions, construction conditions, and design requirements.

[0003] Currently, pipe jacking technology is used in pipelines with diameters ranging from DN800 to 4500, and is widely applied in urban underground water supply and drainage pipelines, natural gas and oil pipelines, and communication cables. It offers advantages such as no ground excavation, no demolition, no damage to surface buildings, no environmental impact, no impact on pipeline deformation due to elevation differences, time-saving, high efficiency, safety, and low overall cost. However, pipe jacking technology in my country also faces challenges including outdated machinery and equipment, significant regional differences, inconsistent construction skill levels, lack of standardization, insufficient personnel, and limited adaptability to various soil types.

[0004] In the process of pipeline renovation in old urban areas, due to the long construction time of the original underground pipelines and the large changes in terrain and landforms, new pipelines are often built by pipe jacking. However, the basic characteristics of urban pipelines are short pipeline distances and flexible spatial layout, especially in mountainous cities in central and western my country. The distribution of underground pipelines is often greatly affected by the terrain, and the geological conditions are often dominated by rock. It is also necessary to consider the impact of pipe jacking construction settlement on ground traffic and surface structures. If pipe jacking machines are used for construction, not only is the single investment large and the construction cost high, but the applicability to pipeline cross-section, pipeline direction, geological lithology, etc. is also not strong. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention proposes a trenchless pipe jacking construction method for traversing rock strata.

[0006] This invention provides a trenchless pipe jacking construction method for penetrating rock strata, comprising the following steps:

[0007] S1. Establish a construction control network: The construction control network is positioned according to the well location axis control piles, and the positions of the working well and the upstream inspection well are checked. The jacking axis is then placed on the measuring platform and well wall of the working well.

[0008] S2. Excavation of the working shaft: The working shaft is excavated to below the lower elevation of the pipe jacking, and the first pilot tunnel for pipe jacking is excavated inside the working shaft;

[0009] S3. Install the back wall: The back wall is fixed to the rock wall with anchors. The back wall is perpendicular to the axis of the jacking pipe. The upper part of the back wall is equipped with a support iron to fix the jacking jack.

[0010] S4. Install guide rails inside the working shaft: The guide rails are supported by several temporary sleepers, and the distance between the bottom of the jacking pipe and the excavation outline is not less than 50mm.

[0011] S5. Pilot tunnel excavation: The pilot tunnel is excavated using manual water drilling to introduce power lines, lighting lines, and ventilation pipes to the working face of the jacking pipe.

[0012] S6. Laying the guide rails inside the guide tunnel: After the guide tunnel is completed, the guide rails inside the guide tunnel are laid. The guide rails are continuously pulled and laid from one end of the working shaft upstream. The guide rails are welded together with steel bars. The guide rails are fixed to the bottom of the guide tunnel with rivets. After the guide rails are laid, the whole system is finely adjusted. After the guide rails are in place, a long steel pipe is placed at the bottom for grouting.

[0013] S7. Pipe Jacking Extension: The pipe sections are lowered onto the guide rails in sections. When the main cylinder of the jack reaches its maximum stroke, it retracts, and the jacking support is inserted to fill the retraction stroke. The main cylinder continues to jack forward. In this way, the jacking support is continuously added, and the pipe sections continue to extend forward. When almost all the pipe sections on the guide rails in the well are jacked into the pipe tunnel, the main cylinder is retracted, all the jacking support is removed, and the next pipe section is lowered into the working well and installed behind the previous pipe section. Jacking continues, and this cycle of construction continues until the upstream inspection well is reached.

[0014] S8. Pipeline grouting: Seal the gap between the two ends of the pipeline and the excavation outline with mortar-grouted rubble, with a sealing length of not less than 300mm. Grout from the working section to fill the outside of the pipeline tightly until thick grout flows out from the upper overflow port at one end of the upstream inspection well, then grouting can be stopped.

[0015] S9. Pipe jacking removal: The pipe jacking facilities in the working shaft will be removed several days later.

[0016] Preferably, in S3, the back wall is made of welded steel profiles.

[0017] Preferably, in S4, the temporary sleepers are evenly distributed in three sections within the working shaft.

[0018] Preferably, in S4, the guide rail is securely fixed by a pre-embedded anchor ring on the top of the temporary sleeper, and wedge-shaped wooden blocks are inserted to finely adjust the height of the top surface of the temporary sleeper.

[0019] Preferably, in S5, the excavation first excavates the perimeter outline according to the design cross section, and then excavates the cross center line in the middle to create a core splitting space. The excavated core is transported to the outside of the pilot tunnel by a trailer.

[0020] Preferably, in S7, the top support is made of steel and has a cross-shaped structure.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a trenchless pipe jacking construction method for crossing rock strata, which does not require the use of a pipe jacking machine, meets the requirements for pipe jacking construction in short-distance rock strata, has strong adaptability to pipe cross-section, slope and orientation, low construction cost, controllable construction period, daily excavation length of 1m / d, small stratum deformation, good control of excavation profile, controllable pipe section installation quality, and high construction safety. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the guide rail structure in an embodiment of the present invention.

[0024] In the diagram: 1. Working shaft; 2. Back wall; 3. Supporting iron; 4. Jacking jack; 5. Guide rail; 6. Temporary sleeper; 7. Top support; 8. Upstream inspection shaft; 9. Masonry block stone; 10. Upstream overflow outlet; 11. Downstream grouting outlet; 12. Cross center line. Detailed Implementation

[0025] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations. Example

[0026] This paper introduces a trenchless pipe jacking construction method for tunneling through rock strata, taking the construction of an urban drainage pipeline through rock strata as an example. The pipe diameter is 1000mm, the length is 29m, and the pipe sections use Class III reinforced concrete pipes specifically designed for pipe jacking, with a length of 2.0m. The pipes use steel socket joints. As the hydraulic pressure of the drainage pipeline decreases, a collection pumping station is eventually needed to raise the water head. The pumping station shaft is used as the working shaft for pipe jacking, and construction proceeds upstream to the inspection well, minimizing construction costs. According to the preliminary geological survey results, the surrounding rock of the pipe jacking section is moderately weathered bedrock with a relatively intact rock stratum shape and little or no groundwater. The natural compressive strength of the moderately weathered bedrock (sandy mudstone) is ≥9.2MPa. The specific construction method includes the following steps:

[0027] S1. Establish a construction control network: The construction control network is positioned according to the well location axis control piles provided by the design institute, and the positions of the actual working well and the upstream inspection well are verified. The jacking axis is projected onto the measuring platform and well wall of the working well. Axial measurement is carried out using the high-precision laser theodolite traverse measurement method. The measuring platform is set at the rear seat of the jacking pipe. At the same time, the design calculations of the back wall, jacking jacks, and jacking supports are carried out. The jacking force calculation needs to take into account the self-weight of the maximum length of the jacking pipe and the friction with the guide rail.

[0028] S2, Excavation of working shaft: such as Figure 1As shown, the working shaft 1 is excavated to 500mm below the lower elevation of the jacking pipe. The first pilot tunnel of the jacking pipe is excavated in the working shaft 1, with a length of 500mm. A water collection well is set in the shaft to pump out construction wastewater in a timely manner.

[0029] S3. Install the back wall: (e.g.) Figure 1 As shown, the back wall 2 is made of welded steel. Before construction, the rock wall of the working well 1 is repaired and loose stones are removed. The back wall 2 is anchored into the rock wall with steel bars. The back wall 2 is perpendicular to the axis of the jacking pipe. The upper part of the back wall 2 is welded with a support iron 3 to fix the jacking jack 4. The jacking jack 4 is a single 10T hydraulic jack with a stroke of 2400mm.

[0030] S4. Install the guide rails inside the working shaft: such as Figure 1 As shown, the guide rail 5 is supported by temporary sleepers 6 cast in place from C30 reinforced concrete. The temporary sleepers 6 are evenly distributed in three sections within the working shaft 1. I12 I-beam guide rails are installed on the top surface of the temporary sleepers 6, as shown. Figure 2 As shown, the spacing of the guide rails 5 meets the requirement of a central angle of 60° for the jacking pipe, and the distance between the bottom of the jacking pipe and the excavation outline is not less than 50mm. The guide rails 5 are securely fixed by the pre-embedded anchor rings on the top of the temporary sleepers 6, and wedge-shaped wooden blocks are added to finely adjust the top surface height of the temporary sleepers 6.

[0031] S5. Pilot Tunnel Excavation: Power lines, lighting lines, and ventilation pipes are introduced to the working face of the jacking pipe. The pilot tunnel is excavated manually with water drills. The excavation first excavates the perimeter outline according to the design cross section, and then excavates the cross center line 12 in the middle to create a core splitting space. The excavated core is transported to the outside of the pilot tunnel by trailer and then vertically transported to the ground by gantry crane. During the construction process, ventilation pipes, water pipes, and power lines follow the excavation working face at all times. Ventilation is provided by forced ventilation using blowers, and lighting is supplemented by LED light strips and headlights.

[0032] S6. Laying the guide rails inside the tunnel: After the tunnel is completed, the guide rails 5 inside the tunnel are laid. They are continuously pulled and laid from one end of the working shaft 1 upstream. The guide rails 5 are welded together with φ20 steel bars at 500mm intervals. The guide rails 5 are firmly fixed to the bottom of the tunnel with rivets. The steel bars and rivets do not exceed the rail surface. After the guide rails 5 are laid, they are finely adjusted as a whole to meet the requirements of the centerline deviation and slope of the jacking pipe installation. The guide rails 5 are not only the base for the moving support of the jacking pipe, but also play a role in the precise positioning of the jacking pipe. After the guide rails 5 are in place, a φ42mm (δ=5mm) long steel pipe is placed at the bottom for grouting.

[0033] S7. Pipe Jacking Extension: The pipe section is lowered onto the guide rail 5 using a gantry crane. When the main cylinder of the jacking jack 4 reaches its maximum stroke, it retracts and the jacking support 7 is inserted. The jacking support 7 is made of steel and has a cross-shaped structure. It fills the retraction stroke, and the main cylinder continues to jack. The jacking support 7 is added continuously, and the pipe section extends forward. When almost all the pipe sections on the guide rail in the well are jacked into the pipe hole, the main cylinder is retracted, all the jacking supports 7 are removed, and the next pipe section is lowered into the working well 1 and installed behind the previous pipe section. The jacking continues, and the construction is repeated until the upstream inspection well 8 is reached.

[0034] S8. Pipeline grouting: Use masonry blocks 9 to seal the gap between the pipeline at both ends and the excavation outline. The sealing length shall not be less than 300mm. Grouting shall be carried out from the working well section. M30 cement mortar shall be used to fill the outside of the pipeline tightly until thick grout flows out of the upstream overflow port 10 at one end of the upstream inspection well 8. Grouting shall be stopped at this point.

[0035] S9. Pipe jacking removal: Remove the pipe jacking facilities in working shaft 1 after 7 days. Pay attention to monitoring and measurement throughout the construction process, mainly including tunnel inspection and surface settlement observation.

[0036] This invention eliminates the need for pipe jacking machines, meets the requirements for pipe jacking construction in short-distance rock strata, has strong adaptability to pipe cross-section, slope, and orientation, low construction cost, controllable construction period, daily excavation length of 1m / d, small stratum deformation, good control of excavation outline, controllable pipe section installation quality, and high construction safety.

[0037] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structures made using the contents of the present invention specification and drawings, whether directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of the present invention.

Claims

1. A trenchless pipe jacking construction method for crossing a rock formation, characterized in that, It comprises the following steps: S1, establishing a construction control network: the construction control network controls the positioning of the pile along the well site axis, and rechecks the point positions of the working well and the upstream inspection well, and puts the jacking axis into the measurement platform of the working well and the well wall; S2, excavating the working well: the working well is excavated to below the lower opening elevation of the pipe jacking, and the first disc guide hole of the pipe jacking is excavated in the working well; S3, installing a back wall: the back wall is fixed to the rock wall by anchor nails, the back wall is perpendicular to the axis of the pipe jacking, and a support iron is installed at the upper part of the back wall for fixing the jacking jack; S4, installing the guide rail in the working well: the guide rail is supported by a plurality of temporary sleepers, and the lower opening of the pipe jacking is away from the excavation contour line by not less than 50mm; S5, guide hole excavation: introduce power lines, lighting lines and ventilation pipes to the working face of the pipe jacking, and excavate the guide hole by artificial water drill; S6, laying the guide rail in the guide hole: after the guide hole is through, the guide rail is laid from one end of the working well to the upstream continuously, the guide rails are welded into a whole by steel bars, the guide rail and the bottom surface of the guide hole are fixed firmly by rivets, and the guide rail is adjusted as a whole after the guide rail is in place. A full-length steel pipe is placed at the bottom for grouting; S7, pipe jacking extension: the pipe section is lowered on the guide rail, the main oil cylinder of the jack is retracted when it reaches the maximum stroke, the support is put in, the retraction stroke is filled, the main oil cylinder continues to jacking, and the support is continuously added, the pipe section is continuously extended forward, the main oil cylinder is retracted when the pipe section on the guide rail in the well is almost all jacked into the pipe hole, all the supports are lifted away, the next pipe section is lifted down the working well, installed behind the front pipe section, and the jacking continues., so as to circulate the construction until it is jacked to the upstream inspection well; S8, pipe grouting: use grouted block stone to block the pipe at both ends and the excavation contour, the blocking length is not less than 300mm, and the pipe outside is filled and compacted from the working well section until the upper overflow port of the upstream inspection well end overflows thick grout, and then the grouting is stopped; S9, pipe jacking removal: remove the pipe jacking facilities in the working well after several days.

2. The trenchless top-of-the-line pipe construction method through rock strata according to claim 1, characterized in that, In S3, the back wall is made of profile steel by welding.

3. The trenchless pipe jacking method of construction through rock strata as claimed in claim 1 or 2 wherein, In S4, the temporary sleepers are evenly distributed in three sections in the working well.

4. The trenchless top-of-the-line pipe construction method through rock strata according to claim 1 or 2, characterized in that, In S4, the guide rail is fixed firmly through the pre-buried anchor ring at the top of the temporary sleeper, and the height of the top surface of the temporary sleeper is finely adjusted by the wedge-shaped wooden frame.

5. The trenchless top-of-the-line pipe construction method through rock strata according to claim 1 or 2, characterized in that, In S5, during the guide hole excavation, first excavate the peripheral contour according to the design section, then excavate the cross center line in the middle to create a rock core splitting space, and the excavated rock core is transported to the outside of the guide hole by a trailer.

6. The trenchless top-of-the-line pipe construction method through rock strata according to claim 1 or 2, characterized in that, In S7, the support is made of steel material in a cross-shaped structure.

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