Small-size pipe jacking well and manual pipe jacking rock breaking method under complex construction conditions

Abstract

The invention discloses a small-size pipe jacking well and a manual pipe jacking rock breaking method under complex construction conditions, and belongs to the technical field of pipeline construction. The method comprises the steps that a pipe jacking well is deepened, so that a safe distance exists between the top of a first pipeline and a box culvert; a measuring net is built, and facilities are arranged in the pipe jacking well; a hole is chiseled and expanded to the size matched with the first pipeline; after it is ensured that the gas concentration in the well reaches the standard, a tool pipe is installed; connecting a second pipeline outside the hole, mounting a hoop with a pulley, sliding into the first pipeline, building a blocking wall, reserving a grouting hole, and grouting according to a water-cement ratio to fill a gap. According to the small-size pipe-jacking well and the manual pipe-jacking rock breaking method under the complex construction condition, the problems of small-size well equipment adaptation and hard rock breaking can be effectively solved, the jacking precision is improved, the influence on the surrounding environment is reduced, and the construction efficiency and safety are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline construction, and in particular relates to a small-sized pipe jacking well and an artificial pipe jacking rock breaking method under complex construction conditions. Background Art

[0002] As an efficient trenchless pipe laying technology, pipe jacking construction is widely used in urban underground space construction. It is particularly suitable for crossing roads, rivers, existing structures and other scenarios to reduce the impact on ground traffic and the surrounding environment.

[0003] However, traditional pipe jacking technology faces multiple challenges in existing small-scale pipe jacking wells and complex construction conditions. First, conventional large-scale mechanical pipe jacking equipment has high requirements for the working well size. When the pipe jacking well size is limited, the equipment cannot be installed or a significant well expansion is required, resulting in increased costs and project delays. Furthermore, even with the use of dedicated rock jacking rigs in hard rock formations, insufficient rock breaking capacity can lead to low construction efficiency. Second, open-cut construction is difficult to implement in busy areas such as urban arterial roads due to the inability to close the excavation. Furthermore, manual pipe jacking requires a pipe diameter of at least 1 meter. When the original design pipe diameter needs to be expanded, the safe vertical distance between the pipe top and the existing box culvert is reduced due to the increased pipe diameter, further increasing construction complexity. Furthermore, when passing under an existing box culvert, the space for adjusting the pipe elevation is extremely limited, requiring extremely high jacking accuracy, further limiting the applicability of conventional methods.

[0004] Existing technologies lack a systematic solution for the coordinated adaptation of small-scale pipe jacking wells to complex construction conditions. Traditional methods struggle to balance construction efficiency, safety, and precision. Therefore, there is an urgent need to develop a method for artificial pipe jacking and rock breaking suitable for small-scale pipe jacking wells and complex construction conditions. Summary of the Invention

[0005] In view of the shortcomings in the related art, the purpose of the present invention is to provide a small-sized pipe jacking well and an artificial pipe jacking rock breaking method under complex construction conditions to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for artificial pipe jacking and rock breaking in a small-sized pipe jacking well and under complex construction conditions, comprising: S1. Deepening the jacking well: Deepen the bottom of the small-sized jacking well to ensure that there is a set vertical distance between the top of the first pipeline and the existing box culvert; S2. Survey preparation and jacking shaft layout: Establish a survey control network to monitor jacking deviation, arrange the main jacking system, excavation and transportation equipment, and ventilation and lighting facilities in the jacking shaft, and remove and expand the original hole structure to accommodate the size of the first pipeline; S3, manual excavation construction: Detect gas concentration in the well and ventilate it to meet the standard. Install a tool pipe at the front end of the first pipeline. Use rock breaking equipment and impact tools in the tool pipe to break the rock layer and transport the excavation debris out. S4. Jacking construction: The method of jacking while digging is adopted. The rock layer excavation is carried out to a set length each time. After the jacking iron is installed, the jack is started to jack the first pipe; S5, penetration and exit: repeat steps S3-S4 until the first pipeline is penetrated; S6. Install the second pipeline: S61. Connect a second pipe outside the hole, and install clamps with pulleys at intervals outside the second pipe. S62, sliding the second pipe into the first pipe through the pulley; S63, building blocking walls at both end ports of the first pipeline, with grouting holes reserved on the blocking walls to communicate with the gap between the first pipeline and the second pipeline; S7. Gap grouting and sealing: prepare filling slurry according to the set water-cement ratio, and inject the slurry into the gap between the first pipe and the second pipe through the grouting hole.

[0007] In some embodiments, step S61 specifically includes: selecting a PE pipe as the second pipe, hot-melt welding the pipe outside the hole, and then installing a clamp with a pulley every 3 meters on the outside of the second pipe.

[0008] In some embodiments, the pulley is connected to the hoop via a support rod, one end of the support rod is connected to the hoop, and the other end of the support rod is connected to the pulley.

[0009] In some embodiments, two support rods and two pulleys are arranged above the second pipe, and the two support rods and pulleys arranged above the second pipe are symmetrically distributed along the radial direction of the second pipe, and the bisector of the angle between the two support rods is perpendicular to the axis of the second pipe; two support rods and two pulleys are arranged below the second pipe, and the two support rods and pulleys arranged below the second pipe are symmetrically distributed along the radial direction of the second pipe, and the bisector of the angle between the two support rods is perpendicular to the axis of the second pipe.

[0010] In some embodiments, the angle between each support rod disposed above the second pipe and the vertical direction is 45°; the angle between each support rod disposed below the second pipe and the vertical direction is 30°.

[0011] In some embodiments, step S1 specifically includes: breaking rock at the bottom of the well, first breaking rock in a circular manner along the outer side of the jacking well to form an air-facing surface, then breaking the intermediate rock layer, and implementing corresponding structural treatment according to the original jacking well type, deepening the bottom of the well to the designed depth, and then using concrete to seal the bottom to a set thickness and maintain it.

[0012] In some embodiments, in step S2, chiseling out and expanding the original hole structure specifically includes: defining a range with the outer diameter of the tool pipe plus 0.1-0.15m, chiseling out the support structure within the range, and cutting the well wall steel bars flush, and installing a water-stop device consisting of a rubber ring, a steel pressure plate and bolts evenly distributed in the circumference on the expanded hole.

[0013] In some embodiments, in step S3, crushing the rock layer specifically includes: using a water-grinding drill to circumferentially construct the outermost rock layer to form an open surface, after the effective footage of the water-grinding drill is set to a length, using a splitting rod to crush the middle rock layer, and using a jackhammer to level the excavation surface.

[0014] In some embodiments, in step S4, the jacking deviation is monitored and corrected in real time during the process of the jacking of the first pipe: the axis center and elevation of the first pipe are measured every 30 cm in the initial stage of jacking, and every 30-50 cm during normal jacking; when the deviation is 10-20 mm, over-excavation correction is adopted, and appropriate over-excavation is performed on the opposite side of the deviation, and a step is left on the deviated side; when the deviation is greater than 20 mm, different jacking forces are applied by the two rear jacks to adjust the axis deviation.

[0015] In some embodiments, step S7 specifically includes: preparing cement slurry according to a water-cement ratio of 1:0.7, connecting the grouting pipe through the reserved grouting hole, and injecting cement slurry into the gap between the first pipe and the second pipe; during the grouting process, controlling the grouting pressure to gradually increase to the design value, and then maintaining the pressure until the slurry is full.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. In the small-sized jacking well and the artificial jacking rock breaking method under complex construction conditions provided by the present invention, by deepening the jacking well, a safe distance between the first pipeline and the existing box culvert is ensured, construction interference is avoided, and the manual excavation construction, jacking construction and through-hole exit process are solved. The problem of limited equipment installation in the small-sized jacking well is solved, rock breaking and jacking under complex conditions are achieved, the second pipeline is installed and grouting is sealed, the pipeline laying is improved, and the overall systematic solution is formed to effectively balance the construction efficiency, safety and precision requirements.

[0017] 2. In the small-sized jacking well and the artificial jacking rock breaking method under complex construction conditions provided by the present invention, support rods and pulleys with specific angles are symmetrically arranged above and below the second pipeline, which optimizes the force structure of the second pipeline, effectively disperses the gravity and sliding friction of the pipeline, provides stable support in a limited space, ensures that the second pipeline slides smoothly and accurately into the first pipeline, and improves the stability and reliability of the pipeline system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 This is a method flow chart of an embodiment of the method for artificial pipe jacking and rock breaking under small-sized pipe jacking wells and complex construction conditions of the present invention; Figure 2 A schematic diagram of a pipe jacking well in accordance with an embodiment of the present invention showing a small-sized pipe jacking well and a method for artificial pipe jacking and rock breaking under complex construction conditions; Figure 3 This is a schematic plan view of the installation of the first pipeline and the second pipeline in one embodiment of the method for artificial pipe jacking and rock breaking under complex construction conditions of a small-sized pipe jacking well according to the present invention; Figure 4 This is a structural schematic diagram of the hole after grouting in one embodiment of a small-sized pipe jacking well and an artificial pipe jacking rock breaking method under complex construction conditions according to the present invention; Figure 5 This is a cross-sectional view of the clamping part after grouting of one embodiment of the method for artificial pipe jacking and rock breaking under complex construction conditions of a small-sized pipe jacking well according to the present invention; Figure 6 This is a schematic diagram of the internal arrangement of a steel casing according to an embodiment of the present invention for a small-sized pipe jacking well and an artificial pipe jacking and rock breaking method under complex construction conditions.

[0019] In the picture: 1. First pipeline; 2. Second pipeline; 3. Pulley; 4. Clamp; 5. Support rod; 6. Blocking wall; 61. Grouting hole; 7. Jacking shaft; 71. Working shaft; 72. Receiving shaft; 8. Box culvert; 9. Grouting pipe; 10. Construction hemp fiber; 11. Guide rail; 111. Sleeper iron; 12. Jacking iron; 13. Jack; 131. Hydraulic pipeline; 14. Small gantry; 141. Winch; 15. Collection well; 16. Steel casing. DETAILED DESCRIPTION

[0020] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "transverse", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0023] See attached Figures 1 to 6 , gives an illustrative embodiment of the small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions proposed by the present invention.

[0024] See attached Figure 2 The small-sized jacking well 7 has been completed. The jacking well 7 includes a working well 71 and a receiving well 72. The strength of the rock pushed from the working well 71 to the receiving well 72 is as high as 150Mpa. Due to the limited size of the jacking well 7, large-scale mechanical jacking equipment cannot be used. Taking into account the cost, construction period, and the fact that the use of a special rock jacking rig in hard rock formations will also lead to low construction efficiency due to insufficient rock breaking capacity, a large-scale well expansion is not carried out.

[0025] In addition, since the pipe jacking shaft 7 is located in a busy traffic area such as a city trunk road, it cannot be closed for excavation, so open excavation cannot be used. The construction area where the pipe jacking is carried out from the working shaft 71 to the receiving shaft 72 has an existing box culvert 8. The elevation adjustment space for the jacked pipe is extremely small, and the jacking accuracy requirement is extremely high. Under such complex construction conditions, the manual pipe jacking and rock breaking method of this embodiment includes the following steps: S1. Deepening the jacking well 7: Deepen the bottom of the small-sized jacking well 7 so that there is a set vertical distance between the top of the first pipeline 1 and the existing box culvert 8; S2. Survey preparation and layout of the jacking shaft 7: Establish a survey control network to monitor jacking deviation, arrange the main jacking system, excavation and transportation equipment, and ventilation and lighting facilities in the jacking shaft 7, and remove and expand the original hole structure to accommodate the size of the first pipeline 1; S3, manual excavation construction: Detect the gas concentration in the well and ventilate it to meet the standard. Install a tool pipe at the front end of the first pipeline 1. Use rock breaking equipment and impact tools in the tool pipe to break the rock layer and transport the excavation debris out. S4. Jacking construction: adopt the method of jacking while digging, set the length of each advance of the rock layer, install the jacking iron, and start the jacking to push the first pipe 1; S5, penetration and exit: repeat steps S3-S4 until the first pipe 1 is penetrated; S6. Install the second pipeline 2: S61. Connect the second pipe 2 outside the hole, and install the clamp 4 with the pulley 3 at intervals outside the second pipe 2; S62, slide the second pipe 2 into the first pipe 1 through the pulley 3; S63, building blocking walls 6 at both ends of the first pipeline 1, with grouting holes 61 reserved on the blocking walls 6 to communicate with the gaps between the first pipeline 1 and the second pipeline 2; S7, gap grouting and sealing: prepare filling slurry according to the set water-cement ratio, and inject the slurry into the gap between the first pipeline 1 and the second pipeline 2 through the grouting hole 61.

[0026] Step S1 specifically includes: breaking the rock at the bottom of the well, first breaking the rock in a circular manner along the outer side of the top pipe well 7 to form an air-facing surface, then breaking the intermediate rock layer, and implementing corresponding structural treatment according to the type of the original top pipe well 7. After deepening the bottom of the well to the designed depth, concrete is used to seal the bottom to a set thickness and maintain it.

[0027] In this embodiment, the jacking shaft 7 includes a working shaft 71 and a receiving shaft 72, wherein the working shaft 71 is a steel casing shaft and the receiving shaft 72 is a reverse excavation shaft. When deepening the steel casing shaft, at least three water-grinding drills are used to first break the annular rock layer outside the steel casing 16, and then the casing is sunk along the excavation surface, with a single rock breaking depth of 75mm; then a "water-grinding drill + splitting rod + jackhammer" is used to break the intermediate rock layer. A new section of steel casing 16 is hoisted, and the upper and lower sections of the casing are welded on one side and double-sided to form the shape, with a controlled gap of 2-3mm. The weld joints are staggered and hammered after cooling. The method for hoisting the slag is to install a small gantry 14 at the top of the pit and transport the stone out using an excavation trolley. The bottom seal is made of C30 plain concrete with a thickness of 300mm. In addition, if the steel casing 16 has difficulty sinking in granite, some rock layers can be removed before sinking, and the gap between the steel casing and the outer soil is filled with cement slurry.

[0028] When deepening a reverse well, two sections of retaining walls are required. When entering the granite layer, the rock can be broken and used as a retaining wall. After entering the rock, at least three hydraulic drills are used to first break the outer annular layer of the wellbore. Then, a "hydraulic drill + splitting rod + jackhammer" system is used to break the intermediate layer. Then, the wellbore is connected to the steel casing, and the excavated soil is hoisted via a small gantry 14. For the bottom seal, rebar is installed first, followed by the pouring of a 350mm thick C30 reinforced concrete bottom seal. The concrete is poured using a string of barrels and cured for at least three days.

[0029] When deepening steel casing wells and deep reverse wells, a water collection well 15 is installed at the top of the corresponding jacking well 7 and equipped with a mud pump to pump out water. A water pump is prepared at the bottom of the corresponding jacking well 7 and is activated to simultaneously reduce water levels when the water volume is high. Specifically, the water collection well 15 is formed by digging a 30cm×30cm×40cm hole in the bottom cover of the jacking well 7. A mud pump is installed in the water collection well 15 to remove accumulated water from the well.

[0030] In step S2, the specific structure of the measurement control network is as follows: (1) Control network around the working well 71: Control points are arranged around the working well 71 to form a measurement benchmark, which is regularly reviewed to ensure stability and serves as a reference for in-well measurement. (2) In-well measurement benchmark: Center pile (axis benchmark): A center pile is set in the working well 71, and a center line is hung to measure the axial deviation of the pipeline; temporary leveling points (elevation benchmark): The permanent leveling point on the ground is led to the well by a vertical hanging steel ruler. Two temporary leveling points are set in the working well 71 to control the elevation and slope of the pipeline, and the accuracy is checked by closed measurement. (3) Measuring instruments and installation: A high-precision laser theodolite (for axial measurement), a level and an elevation ruler (for elevation measurement) are installed on the bracket behind the first pipeline 1. The bracket is reliably connected to the base plate to ensure stable measurement. (4) Auxiliary judgment: Combined with the track assembly status of the excavation trolley, if the track is deflected, auxiliary judgment is made as to whether the pipeline has axis or elevation deviation.

[0031] In step S2, the original opening structure is removed and expanded. Specifically, the outer diameter of the tool pipe plus 0.1-0.15m is used to define an area, and the support structure and water-stop curtain within this area are removed. The support structure includes steel casing 16, reverse-cut shaft wall, and retaining piles. After removal, the shaft wall reinforcement is cut flush to prevent it from being stuck by obstacles when the first pipe 1 is pushed in. The expanded opening is then installed with a water-stop device consisting of a rubber ring, a steel pressure plate, and bolts evenly distributed around the circumference. The steel pressure plate is compressed against the rubber ring by the bolts, making it fit tightly against the outer wall of the first pipe 1 and the edge of the opening, forming a waterproof barrier to prevent groundwater, muddy water, or soil particles from flowing into the working shaft 71 through the gap.

[0032] In step S2, before jacking the first pipeline 1, a guide rail 11 is installed in the working shaft 71. The slope of the guide rail 11 is consistent with the designed slope of the first pipeline 1. The first pipeline 1 is subsequently jacked along the guide rail 11 through the main jacking system. The main jacking system includes a steel backrest, a jacking iron 12 and at least two jacks 13.

[0033] The guide rails 11 are installed in the working well 71. Specifically, the guide rails 11 are connected on the ground with channel steel and hoisted and lowered as a whole. The position of the jacking pipe base is accurately laid out according to the pipeline design axis. The two guide rails 11 are straight, parallel and of equal height. The longitudinal slope is consistent with the design slope of the first pipeline 1. During installation, they are hoisted into the well and fixed in place according to the measured and laid-out baseline. The guide rails 11 on the base are placed in the center according to the jacking pipe design axis and the measured tunnel center, and are supported and reinforced with steel pipes to ensure that the base is stable and does not deform. In this embodiment, the guide rails 11 can be made of 20a channel steel, and the distance between the two guide rails 11 is 80cm. There are spaced sleeper irons 111 below the guide rails.

[0034] See attached Figure 6 In this embodiment, the main jacking system is equipped with two 2000 kN (200 t) double-stroke equal-thrust jacks 13, with a total thrust of 4000 kN. The center error of the installed jacks 13 should be less than 10 mm. The two jacks 13 are connected to an external hydraulic pump station via hydraulic pipelines 131, which provides hydraulic power to the jacks 13 to achieve the jacking action.

[0035] During jacking, the reaction force of the jack is evenly transmitted to the well wall through the steel backrest to avoid uneven force on the well wall or excessive force on the well wall causing damage to the well wall structure. The steel backrest should be kept perpendicular to the jacking axis during installation, while ensuring overall contact. The steel backrest steel plate adopts δ=30 hollow steel plate, and the area of the pressure wall is H×B=3×2.5m. In this embodiment, for the reverse well, the steel backrest should be set and close to the well wall of the reverse well. For the steel casing 16, since the steel casing 16 can play the role of steel backrest, it does not need to be set. The attached figure is a schematic diagram of the steel casing 16, so the steel backrest is not shown.

[0036] In this embodiment, the top iron 12 of the main top system is an annular top iron, and its outer diameter is consistent with the diameter of the first pipe 1. The top iron 12 is welded with 30 mm thick steel plates to ensure sufficient rigidity. Reinforcing ribs can be arranged at the position of the jack 13, and the contact surface between the annular top iron and the pipe mouth can also be provided with a 20 mm thick pine wood board lining as a buffer material.

[0037] In this embodiment, the working shaft 71 is also provided with a small gantry 14. Specifically, in order to facilitate the excavation of the transport trolley and the hanging of the pipeline, a small gantry 14 is installed above the working shaft 71. The maximum lifting capacity of the small gantry 14 is 2.8t, the span is 7m, the cantilever length on both sides is L=1m, the total weight of the electric hoist is 300kg, the legs are made of square tube 120×120×4, the material is Q235B, the legs are 4m high, the bottom is 3m wide, and both legs are made of square tube combination welded together. The main beam specification is selected to be made of I30B I-beam + 12# channel steel, and the material is Q235B. It is fixed to the ground at the top of the foundation pit through expansion screws. A winch 141 is installed at the middle top of the small gantry 14 for lifting and lowering to achieve the function of transporting soil, mainly bearing a load of 2.8t.

[0038] In step S3, rock stratum crushing specifically involves using a water-mill drill to circumferentially drill the outermost rock layer to form an open face. After the water-mill drill has effectively advanced to a set length, the intermediate rock layer is crushed using a splitting rod, and the excavation face is leveled using a jackhammer. In this embodiment, the rock layer being crushed is a moderately weathered rock layer with a uniaxial compressive strength of 150 MPa. If only the outer ring is crushed, the intermediate rock layer would be difficult to crush due to its strong integrity. Therefore, for the intermediate rock layer, a water-mill drill is first used to drill holes in the intermediate rock layer to form an open face, thereby dividing the large rock mass into several smaller pieces. The rock is then crushed using a splitting rod and a jackhammer.

[0039] The hydraulic drill is secured in the pipe via a mounting bracket. In this embodiment, deploying two hydraulic drills simultaneously would be inconvenient for technicians due to the limited construction space. Furthermore, simultaneous operation of the two drills would cause interference due to vibration, posing a safety hazard. Therefore, in this embodiment, one hydraulic drill is mounted on the mounting bracket via a fall chain and a hand hoist. The bottom support of the hydraulic drill is placed against the rock to be excavated and secured to the excavation surface using expansion screws. This approach satisfies rock breaking requirements while avoiding space conflicts.

[0040] In the manual excavation construction of step S3, the specific implementation method of the water-grinding drill and splitting rod in the rock-breaking equipment is as follows: the water-grinding drill is suspended and fixed on a steel fixed frame in the tool tube by a fall chain and a hand hoist. Its bottom end support directly supports the surface of the rock layer to be excavated and is fastened to the rock layer surface with expansion screws to ensure that the equipment is stable and does not shake during construction. Due to the small space in the tool tube, only one water-grinding drill is arranged to avoid vibration interference or operation conflicts of multiple devices. During construction, first drill holes in a circular direction along the pipeline excavation contour line for the outermost rock layer, and control the single rock breaking depth to 75mm. Gradually cut to form an annular free surface to weaken the integrity of the rock layer; then drill holes in the middle rock layer within the annular free surface with a water-grinding drill at a spacing of 30-50cm, dividing the large rock mass into several small pieces, creating conditions for subsequent crushing. The splitting rod is used after the hydraulic drill has completed drilling the intermediate rock layer. It is inserted into the pre-drilled hole, and pressure is applied by a hydraulic pump. The lateral force generated by the rod's expansion and contraction causes the rock to crack along the gaps in the drilled hole. For moderately weathered granite with a uniaxial compressive strength of 150 MPa, after splitting a single hole, the rod is replaced and repeated in the adjacent drill hole until the intermediate rock layer is completely broken into small, removable pieces. The crushed rock fragments are then leveled with a jackhammer to ensure the excavation profile meets the designed pipeline dimensions and facilitates the removal of the excavated soil.

[0041] In step S4, the jacking deviation is monitored and corrected in real time during the process of the jacking of the first pipe 1: the axis center and elevation of the first pipe 1 are measured every 30 cm in the initial stage of jacking, and every 30-50 cm during normal jacking; when the deviation is 10-20 mm, over-excavation correction is adopted, and appropriate over-excavation is performed on the opposite side of the deviation, and a step is left on the deviated side; when the deviation is greater than 20 mm, different jacking forces are applied by the two rear jacks to adjust the axis deviation.

[0042] In step S5, repeat steps S3-S4 until the jacking is about to be in place, slow down the jacking speed, accurately measure the exit position, remove the sealing door of the receiving well hole, push the pipe section of the first pipeline 1 to the predetermined position, remove the jacking equipment and clean the site.

[0043] In step S5, after the first pipeline is penetrated and before the second pipeline is installed, grouting is performed between the first pipeline and the rock formation to stabilize the first pipeline and prevent water seepage from the rock formation, which could cause the first pipeline to sink. After grouting, once the strength reaches the standard required for continued construction, step S6 is performed to install the second pipeline, thus preventing displacement of the first pipeline from affecting subsequent processes.

[0044] Step S61 specifically includes: selecting a PE pipe for the second pipe 2, and hot-melt welding the pipe outside the hole. The spacing of the clamps 4 is set according to the diameter, length and deadweight of the second pipe 2. In this embodiment, a clamp 4 with a pulley 3 is installed every 3 meters on the outside of the second pipe 2. The blocking wall 6 built in step S63 includes a brick wall and a waterproof mortar layer. The blocking wall 6 can provide a sealing boundary for gap grouting to ensure that the annular space between the second pipe 2 and the first pipe 1 can be fully filled with slurry. The grouting hole 61 can be installed with a grouting pipe 9. In this embodiment, the grouting pipe 9 is a PVC pipe, which is pre-buried in the gap between the second pipe 2 and the first pipe 1. The grouting port of the grouting pipe 9 extends to the outside of the blocking wall 6.

[0045] In some embodiments, the pulley 3 located below the second pipe 2 is directly connected to the clamp 4. This direct connection between the pulley 3 and the clamp 4 eliminates the need for intermediate adapters, allowing for quick positioning and installation. This reduces the complexity of operations in the confined space of a small-sized pipe jacking shaft 7 and shortens the overall installation time of the second pipe 2. Furthermore, the direct connection offers a simple structure and enhanced stability.

[0046] See attached Figure 5 In this embodiment, the pulley 3 is connected to the hoop 4 through the support rod 5. One end of the support rod 5 is connected to the hoop 4, and the other end is connected to the pulley 3. The axis of the pulley 3 is parallel to the axis of the second pipe 2.

[0047] Two support rods 5 and two pulleys 3 are arranged above the second pipe 2. The two support rods 5 and the pulleys 3 arranged above the second pipe 2 are symmetrically distributed along the radial direction of the second pipe 2, and the angle bisector of the two support rods 5 is perpendicular to the axis of the second pipe 2; two support rods 5 and two pulleys 3 are arranged below the second pipe 2. The two support rods 5 and the pulleys 3 arranged below the second pipe 2 are symmetrically distributed along the radial direction of the second pipe 2, and the angle bisector of the two support rods 5 is perpendicular to the axis of the second pipe 2. See Appendix. Figure 3 and Figure 5 The lengths of the two support rods 5 above the second pipe 2 and the two support rods 5 below the second pipe 2 can be different to adapt to different actual construction requirements.

[0048] The included angle between each support rod 5 arranged above the second pipe 2 and the vertical direction is 45°; the included angle between each support rod 5 arranged below the second pipe 2 and the vertical direction is 30°.

[0049] The support rod 5 and pulley 3 above the second pipe 2 offset the upward buoyancy and lateral deflection forces of the second pipe 2, helping to center the second pipe 2 and reducing friction at the top. Specifically, the 45° angle allows the support rod 5 to simultaneously withstand both vertical and horizontal lateral force components (with a force ratio of 1:1). During pipe jacking, the second pipe 2 may tend to deflect upward due to air pressure within the annular gap, the buoyancy of the grouting fluid, or eccentric forces during thrust. The 45° pulley 3 above provides diagonal support, providing both an upward lifting force (vertical component) and a horizontal restraining force (lateral component), doubly inhibiting the pipe from tilting or tilting. Furthermore, the 45° arrangement maintains an oblique distance between the pulley 3 and the top inner wall of the first pipe 1. When the second pipe 2 slides in and slightly sags due to its own weight, the oblique support of the upper pulley 3 "pushes" the second pipe 2 to remain centered through the horizontal force component, preventing friction between the top pipe wall and the first pipe 1 and potentially scratching the second pipe 2.

[0050] The support rod 5 and pulley 3 located below the second pipe 2 bear the vertical weight of the second pipe 2, providing stable support and preventing the bottom of the second pipe 2 from "sticking" to the wall, reducing the risk of friction damage. Specifically, the vertical force component at a 30° angle is greater than the horizontal force component (vertical force = support rod tension × cos 30° ≈ 0.866 times, horizontal force ≈ 0.5 times). Therefore, the lower pulley 3 primarily supports the weight of the second pipe 2 through the vertical force component. For example, if the second pipe 2 is made of DN300 PE pipe (10mm wall thickness, 10m length) and weighs approximately 500kg, the two lower pulleys can provide a vertical lifting force of approximately 8660N (approximately 4330N per pulley) through the 30° support rod, ensuring that the second pipe 2 does not sag or deform. Furthermore, the lower pulley 3 supports the second pipe 2 at a 30° angle, maintaining a gap between the bottom of the second pipe 2 and the inner wall of the first pipe 1, preventing it from completely sticking to the bottom pipe wall due to its own weight. Especially during long-distance jacking, if the pipe sags and sticks to the wall, the friction resistance at the bottom will be large during advancement and may damage the pipe. The 30° support can maintain the gap through vertical force distribution and improve advancement efficiency.

[0051] Step S7 specifically includes: preparing cement slurry according to a water-cement ratio of 1:0.7, connecting the grouting pipe 9 through the reserved grouting hole 61, and injecting cement slurry into the gap between the first pipe 1 and the second pipe 2; during the grouting process, controlling the grouting pressure to gradually increase to the design value, and then maintaining the pressure until the slurry is full.

[0052] After the grouting is completed, the second pipe 2 is wrapped with construction hemp 10. After the grouting liquid solidifies, micro cracks may be generated due to volume shrinkage. The porous structure of the hemp fiber can absorb the residual grouting liquid or infiltrated water to form a "fiber-slurry" composite sealing layer. The flexible filling of the construction hemp 10 at the pipe interface can make up for the natural defects of the grouting process and prevent leakage. In the above-mentioned schematic embodiment, the method of artificial jacking and rock breaking in a small-sized jacking well and complex construction conditions ensures a safe distance between the first pipeline and the existing box culvert by deepening the jacking well, avoids construction interference, and solves the problem of limited equipment installation in a small-sized jacking well. It realizes rock breaking and jacking under complex conditions, installs the second pipeline and grouting and sealing, improves pipeline laying, and forms a systematic solution as a whole, effectively balancing construction efficiency, safety and precision requirements.

[0053] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to preferred embodiments, persons skilled in the art should understand that the specific implementation methods of the present invention may still be modified or some technical features may be replaced by equivalents without departing from the spirit of the technical solutions of the present invention, and all of these should fall within the scope of the technical solutions claimed for protection by the present invention.

Claims

1. A small-sized pipe jacking well and an artificial pipe jacking rock breaking method under complex construction conditions, characterized in that: include: S1. Deepening the jacking well: Deepen the bottom of the small-sized jacking well to ensure that there is a set vertical distance between the top of the first pipeline and the existing box culvert; S2. Survey preparation and jacking shaft layout: Establish a survey control network to monitor jacking deviation, arrange the main jacking system, excavation and transportation equipment, and ventilation and lighting facilities in the jacking shaft, and remove and expand the original hole structure to accommodate the size of the first pipeline; S3, manual excavation construction: Detect gas concentration in the well and ventilate it to meet the standard. Install a tool pipe at the front end of the first pipeline. Use rock breaking equipment and impact tools in the tool pipe to break the rock layer and transport the excavation debris out. S4. Jacking construction: The method of jacking while digging is adopted. The rock layer excavation is carried out to a set length each time. After the jacking iron is installed, the jack is started to jack the first pipe; S5, penetration and exit: repeat steps S3-S4 until the first pipeline is penetrated; S6. Install the second pipeline: S61. Connect a second pipe outside the hole, and install clamps with pulleys at intervals outside the second pipe. S62, sliding the second pipe into the first pipe through the pulley; S63, building blocking walls at both end ports of the first pipeline, with grouting holes reserved on the blocking walls to communicate with the gap between the first pipeline and the second pipeline; S7. Gap grouting and sealing: prepare filling slurry according to the set water-cement ratio, and inject the slurry into the gap between the first pipe and the second pipe through the grouting hole.

2. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 1 are characterized in that: Step S61 specifically includes: selecting a PE pipe for the second pipe, heat-melting the pipe outside the hole, and then installing a clamp with a pulley every 3 meters on the outside of the second pipe.

3. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 2 are characterized in that: The pulley is connected to the hoop through a support rod, one end of the support rod is connected to the hoop, and the other end is connected to the pulley.

4. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 3 are characterized in that: Two support rods and two pulleys are arranged above the second pipeline, and the two support rods and pulleys arranged above the second pipeline are symmetrically distributed along the radial direction of the second pipeline, and the angle bisector of the two support rods is perpendicular to the axis of the second pipeline; two support rods and two pulleys are arranged below the second pipeline, and the two support rods and pulleys arranged below the second pipeline are symmetrically distributed along the radial direction of the second pipeline, and the angle bisector of the two support rods is perpendicular to the axis of the second pipeline.

5. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 4 are characterized in that: The included angle between each support rod arranged above the second pipe and the vertical direction is 45°; the included angle between each support rod arranged below the second pipe and the vertical direction is 30°.

6. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 1 are characterized in that: Step S1 specifically includes: breaking the rock at the bottom of the well, first breaking the rock in a circular manner along the outer side of the top pipe well to form an air-facing surface, then breaking the middle rock layer, and implementing corresponding structural treatment according to the original top pipe well type, deepening the bottom of the well to the designed depth, and then using concrete to seal the bottom to set the thickness and maintain it.

7. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 1 are characterized in that: In step S2, chiseling and expanding the original hole structure specifically includes: defining a range with the outer diameter of the tool pipe plus 0.1-0.15m, chiseling out the support structure within the range, and cutting the well wall steel bars flush, and installing a water-stop device consisting of a rubber ring, a steel pressure plate and bolts evenly distributed in the circumference on the expanded hole.

8. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 1 are characterized in that: In step S3, the rock layer crushing specifically includes: using a water-grinding drill to circumferentially construct the outermost rock layer to form an open surface, after the effective footage of the water-grinding drill is set to a length, the middle rock layer is crushed by a splitting rod, and the excavation surface is leveled with a jackhammer.

9. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 1 are characterized in that: In step S4, the jacking deviation is monitored and corrected in real time during the process of the jacking of the first pipe: the axis center and elevation of the first pipe are measured every 30 cm in the initial stage of jacking, and every 30-50 cm during normal jacking; when the deviation is 10-20 mm, over-excavation correction is adopted, and appropriate over-excavation is performed on the opposite side of the deviation and a step is left on the deviation side; when the deviation is greater than 20 mm, different jacking forces are applied by the two rear jacks to adjust the axis deviation.

10. The small-sized pipe jacking well and the artificial pipe jacking rock breaking method under complex construction conditions according to claim 1, characterized in that: Step S7 specifically includes: preparing cement slurry according to a water-cement ratio of 1:0.7, connecting the grouting pipe through the reserved grouting hole, and injecting cement slurry into the gap between the first pipe and the second pipe; during the grouting process, controlling the grouting pressure to gradually increase to the design value, and then maintaining the pressure until the slurry is full.

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