Large-section rectangular pipe jacking receiving construction method for water-rich sand layer

Abstract

The invention provides a large-section rectangular jacking pipe receiving construction method for a water-rich sand layer, and relates to the technical field of jacking pipe receiving construction. Comprising the steps of receiving preparation, receiving tunnel portal chiseling, receiving frame and water stopping device installation, water and soil backfilling in a receiving well, jacking in place of a pipe jacking machine, water pumping and soil cleaning in the receiving well and tunnel portal blocking, intermediate jacking station closing, pipe joint periphery slurry solidification and the like. The method includes the steps of receiving preparation, receiving tunnel portal chiseling, receiving frame and water stopping device installation, water and soil backfilling in the receiving well, in-place jacking of a pipe jacking machine, water pumping and soil cleaning in the receiving well and tunnel portal blocking. According to the method, personnel injury and economic loss caused by water leakage can be reduced to the maximum extent, so that safe and efficient carrying out of water-rich sand layer stratum pipe jacking receiving is realized, and reliable technical guarantee is provided for similar projects.

Description

TECHNICAL FIELD

[0001] The application relates to a pipe jacking receiving construction technology field, in particular to a large-section rectangular pipe jacking receiving construction method in a water-rich sand layer. BACKGROUND

[0002] With the acceleration of urbanization, underground space development has become an important way to alleviate the shortage of land resources, traffic congestion and other urban diseases. Under this background, the rectangular pipe jacking technology gradually becomes the preferred solution in urban underground engineering construction due to its significant advantage of minimal disturbance to ground transportation and environment. The technology precisely jacks the rectangular section pipe joint into the underground through the jacking equipment, balances the underground water and soil pressure by using the soil pressure or mud pressure in the soil chamber, thereby minimizing the impact of construction on the surrounding environment, and finally realizes the non-excavation laying. The rectangular pipe jacking technology has been widely applied to various engineering such as underground space development, underground pedestrian passageway, comprehensive pipe gallery, underpass road tunnel, underground space interconnection, subway station entrance and exit and underground excavation station, and represents the development direction of the future urban short-distance rectangular tunnel construction technology.

[0003] Pipe jacking receiving is the most difficult to control in the pipe jacking construction process. The conventional pipe jacking receiving method is as follows: firstly, the ground around the receiving well is reinforced, for example, the freezing method, deep well dewatering or grouting reinforcement method is used to improve the stability and water resistance of the surrounding soil; secondly, a steel receiving bracket is installed in the receiving well for supporting and guiding the pipe jacking head; then, when the pipe jacking head approaches the receiving well, the jacking speed is gradually reduced, and the monitoring is strengthened to ensure that the pipe jacking head can accurately enter the receiving bracket; finally, after the pipe jacking head enters the receiving well, the hole is quickly sealed to prevent water and soil loss. However, the sand particles in the water-rich sand layer have large interstitial pores, the underground water connectivity is excellent, and the self-stability is extremely poor, which is extremely easy to flow and liquefy under construction disturbance. In this case, the conventional method for pipe jacking receiving has a great risk of water leakage. Once it occurs, it may cause the pipe jacking head to deviate from the direction and the receiving to fail, or even cause large-scale ground subsidence, collapse, and even endanger the safety of surrounding buildings and personnel, and cause serious safety accidents. Therefore, how to efficiently complete the pipe jacking receiving in the water-rich sand layer under the premise of ensuring safety has become a technical problem to be solved. SUMMARY

[0004] In view of the above prior art, the application provides a large-section rectangular pipe jacking receiving construction method in a water-rich sand layer. The pipe jacking receiving by the method can minimize the personnel injury and economic loss caused by water leakage, thereby realizing safe and efficient pipe jacking receiving in the water-rich sand layer and providing reliable technical support for similar engineering.

[0005] The large-section rectangular pipe jacking receiving construction method in a water-rich sand layer provided by the application comprises the following steps:

[0006] S1, receiving preparation: the pipe jacking machine is a certain distance away from the receiving well as a pipe receiving section, and the pipe receiving is prepared to start;

[0007] S2, receiving hole portal removal: when the receiving hole portal reinforcement meets the design requirements and is accepted, the surrounding structure within the receiving hole portal is removed, and the surrounding structure is removed under the qualified reinforcement during the removal;

[0008] S3, receiving frame and water stop device installation: after the receiving hole portal is removed, the receiving hole portal position is measured and confirmed, the pipe jacking machine receiving frame is installed according to the actual pipe jacking machine elevation, and the water stop device is installed at the receiving hole portal;

[0009] S4, soil and water backfilling in the receiving well: after the receiving frame and water stop device installation is completed, the soil and water are immediately backfilled into the receiving well, so that the water and soil pressure inside and outside the receiving well is balanced;

[0010] S5, pipe jacking machine jacking into position: after the water and soil backfilling is completed, the pipe jacking machine is jacked out of the hole again and jacked into the design position;

[0011] S6, water pumping and soil cleaning in the receiving well and hole portal sealing: water is pumped in the receiving well, and backfilled soil is cleaned layer by layer, and the receiving hole portal is sealed at the same time as the cleaning progress;

[0012] S7, pipe jacking machine and pipe joint separation: the pipe jacking machine and the first pipe joint are separated, translated to the hoisting hole position, and hoisted out of the well after being disassembled;

[0013] S8, relay closure: after the pipe jacking is completed, the relay is closed and filled with concrete construction;

[0014] S9, pipe joint peripheral slurry solidification: the system and pipeline of pressure injection thixotropic mud are used for cement slurry solidification.

[0015] Preferably, in S1, the receiving hole portal reinforcement adopts a combination of triaxial mixing pile and vertical freezing, the freezing reinforcement method is plate block freezing wall soil reinforcement, the freezing wall is closely attached to the underground continuous wall of the receiving well, the actual active freezing days are determined according to the temperature field monitoring of the engineering site, after freezing is completed, 9 meter-shaped exploration holes are drilled at the receiving hole portal using a water drill, the exploration hole depth is 100mm more than the underground continuous wall, the exploration hole diameter is 50mm, a temperature measuring wire is installed in the exploration hole to measure the exploration hole temperature and evaluate the freezing effect of the receiving hole portal.

[0016] Preferably, in S2, 9 observation holes are drilled at the receiving portal position before the underground continuous wall is broken, the hole diameter is 80mm, and the drilling depth ensures that the reinforced soil is drilled. A ball valve is installed at the hole position, and the outside of the ball valve is sealed with quick-drying cement. Before the underground continuous wall is broken, the ball valve is opened at regular intervals to observe whether water flows out, and the reinforced soil condition outside the receiving portal is continuously observed. After judging that there is basically no clear water, the underground continuous wall is immediately broken.

[0017] Preferably, in S3, the receiving frame includes a receiving base and a guide device, the receiving base includes a concrete guide table, a 32#a channel steel and a P43 guide rail, the guide table adopts C30 concrete, the reinforcement of the guide table adopts Φ16 main reinforcement and Φ8@300 stirrup, the channel steel anchor adopts Φ20@400 anchor reinforcement, and the center axis of the receiving base is consistent with the tunnel design axis; two guide devices are arranged at the bottom of the receiving portal, the guide device is 5mm lower than the bottom of the pipe jacking machine head, and the receiving base is 5mm lower than the guide device.

[0018] Preferably, in S3, the water stop device includes two annular steel plates and a wire, the annular steel plate is 10-30mm higher than the outer wall of the pipe joint, the thickness is 3mm, a triangular support is arranged between the two annular steel plates, a 10mm high notch is cut at a position corresponding to each triangular support, and a wire is inserted between the two annular steel plates, the height of the wire is 25cm, and 2 grouting holes are reserved on the upper, lower, left and right of the portal steel ring as subsequent emergency grouting holes.

[0019] Preferably, in S4, the remaining frozen pipes outside the 2 rows of frozen pipes on the left and right sides of the pipe jacking machine are thawed by circulating hot brine and pulled out, and the frozen pipe is pulled out in the following manner: the frozen hole is forcibly thawed by using preheated hot brine, after 5-8 minutes of hot brine circulation thawing, the frozen pipe after thawing is pulled out by using the automobile crane, when the frozen pipe is heated to be able to be twisted appropriately, the pipe can be pulled out, when the frozen pipe is pulled out by 0.5m, the circulation of hot brine is stopped, the salt water in the pipe is discharged by compressed air, and the frozen pipe is quickly pulled out.

[0020] Preferably, in S5, when the pipe jacking machine cutter tip is 6m away from the receiving portal, the grouting of the first pipe joint is stopped, and the grouting position is gradually moved backward during the subsequent pipe jacking process, so as to ensure that a perfect 6m soil plug is formed before the pipe jacking enters the portal.

[0021] Preferably, in S5, the pipe jacking machine advances in the backfill of the receiving shaft, and the advancing speed is controlled at 5-10 mm / min; the pipe jacking machine stops advancing until the first pipe section protrudes 50 cm from the receiving hole portal, a support is arranged at a predetermined position on the track of the receiving frame to prevent the pipe jacking machine from sliding forward, and the first longitudinal tensioning member is used to prevent the pipe section from loosening.

[0022] Preferably, in S8, when the pipe jacking machine starts to enter the receiving shaft, the intermediate relay oil cylinder is retracted to the minimum position, and the front and rear shell bodies are connected and tightly connected at the pipe openings.

[0023] After the jacking construction is completed, the front jacking oil cylinder is removed, and the double-liquid cement slurry is injected from the high to the low position of the intermediate relay through the grouting hole, replacing the thixotropic slurry that plays a role in reducing resistance during pipe jacking, filling the gap between the front and rear shell bodies, and if there is leakage, secondary grouting is performed, and after grouting is completed, the grouting hole is sealed.

[0024] The jacking equipment in the intermediate relay is removed from front to back, and the intermediate relay circuit, control system, oil pump station, oil circuit, and jack are removed in sequence; the sequence of removing each intermediate relay is: first the top, then the two sides, and finally the bottom; the front and rear shell body connecting plates of the intermediate relay are welded, the annular inner lining plate of the rear section is welded with the front section shell, and the movable part of the intermediate relay is completely sealed; the surface oil stains of the intermediate relay are removed with a detergent, the steel mesh is installed, the formwork is installed, and the micro-expanding concrete is poured in three times according to the sequence of first bottom, then two sides, and finally bottom.

[0025] The second longitudinal tensioning member is used to pass through the prestressed tendon through the prestressed hole channel pre-buried in all rectangular pipe sections, and prestressed tensioning is performed after the pipe jacking is completed.

[0026] Preferably, in S9, after the receiving is in place, the grouting method from both ends to the middle is adopted; the water-cement ratio of the solidified cement slurry is 0.7-0.8, the slurry specific gravity is 1.26-1.28, the grouting pressure is 0.3-0.5 MPa, and the grouting amount is ≥1.02 m3 / section.

[0027] The beneficial effects of the present application relative to the prior art are as follows: 1) for water-rich sand layer geology, the receiving portal is reinforced by triaxial mixing pile + vertical freezing method, which utilizes the rapid construction and water-stopping capacity of mixing pile and the high strength and stability of freezing method, forming a double reinforcement effect, effectively preventing risks such as water and sand gushing at the receiving portal. 2) for cold reinforcement, after the water and soil backfill of the receiving well, the remaining frozen pipes outside the left and right sides of the pipe jacking machine are thawed and removed, and after reaching the receiving well, the first-10 pipe sections are injected with double-liquid slurry through 1-inch holes for slurry solidification, and then the left and right sides of the pipe jacking machine are removed. Through the combination of "frozen wall thawing in stages + double-liquid slurry active plugging", the three goals of safe receiving, efficient water stopping and soil reinforcement are achieved. 3) for water-rich environment, the receiving portal forms a reliable water-stopping system through the combination of two annular steel plates + wire, achieving soil and water blocking and ensuring the safety of pipe jacking receiving construction. 4) to simulate the original soil working environment, the water and soil backfill in the receiving well provides necessary support and stability for the pipe jacking machine receiving operation, and through the given backfill soil height calculation formula and the type of backfill soil, the water and soil pressure inside and outside the well is balanced, preventing groundwater from flowing into the receiving well. 5) During receiving, the first and second longitudinal tensioning members firmly connect each pipe section together to prevent relative displacement between pipe sections. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flowchart of the water-rich sand layer large-section rectangular pipe jacking receiving construction method in the embodiment of the present application.

[0029] Figure 2 The receiving well schematic diagram in the embodiment of the present application.

[0030] Figure 3 The guide device schematic diagram in the embodiment of the present application.

[0031] Figure 4 The water-stopping device schematic diagram in the embodiment of the present application.

[0032] Figure 5 The receiving portal core hole schematic diagram in the embodiment of the present application.

[0033] Figure 6 The water-rich sand layer large-section rectangular pipe jacking receiving plan view in the embodiment of the present application.

[0034] Figures 7-8 The water-rich sand layer large-section rectangular pipe jacking receiving elevation view in the embodiment of the present application.

[0035] Figure 9 The frozen pipe removal schematic diagram after water and soil backfill in the embodiment of the present application.

[0036] Figure 10 This is a schematic diagram of the removal of the frozen pipe after injecting the double-liquid slurry into pipe sections 1-10 in an embodiment of the present invention.

[0037] Figure 11 This is a schematic diagram showing the location of the grouting holes in the relay station in an embodiment of the present invention.

[0038] In the diagram: 1. Core tube exterior wall; 2. Cantilever slab; 3. Construction adjustment joint; 4. Floor slab aluminum formwork; 5. Diagonal brace; 6. Floor deck connecting reinforcement; 7. Tie rod; 8. Floor deck. Detailed Implementation

[0039] 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 embodiments.

[0040] Example: Figures 1-11 The method for receiving large-section rectangular jacking pipes in water-rich sand layers, as shown, includes the following steps:

[0041] S1. Receiving preparation: The distance between the pipe jacking machine and the receiving well is designated as the pipe jacking receiving section, and preparation is made to start pipe jacking receiving;

[0042] The reinforcement of the receiving tunnel portal adopts a combination of triaxial mixing piles and vertical freezing reinforcement measures. The freezing reinforcement method is to reinforce the soil of the plate freezing wall. The frozen wall is closely attached to the underground continuous wall of the receiving well. The actual number of active freezing days is determined according to the temperature field monitoring at the project site. After freezing, nine cross-shaped probe holes are drilled at the receiving tunnel portal using a water drill. The probe hole depth is more than 100mm beyond the underground continuous wall and the probe hole diameter is 50mm. Temperature measuring wires are installed in the probe holes to measure the probe hole temperature and evaluate the freezing effect of the receiving tunnel portal.

[0043] As the pipe jacking machine gradually approaches the receiving well, the surveyors re-measure the attitude of the pipe jacking machine and increase the frequency and accuracy of the measurements. Based on the re-measurement results, they promptly correct any deviations to ensure that the pipe jacking machine can be accurately received. Only after ensuring that the reinforcement range, strength, and water-stopping properties of the receiving end meet the design requirements and the attitude of the pipe jacking machine are verified can the removal of the receiving tunnel entrance be completed.

[0044] S2. Receiving Tunnel Removal: After the receiving tunnel reinforcement meets the design requirements and passes the acceptance test, the retaining structure within the receiving tunnel area shall be removed. During the removal process, ensure that the retaining structure is removed while the reinforcement is in good condition.

[0045] Before breaking the diaphragm wall, nine observation holes with a diameter of 80 mm were drilled at the receiving tunnel entrance. The drilling depth was ensured to reach the reinforced soil. Ball valves were installed at the drilling locations and sealed on the outside with quick-drying cement. Before breaking the diaphragm wall, the ball valves were opened periodically to observe whether water flowed out. The condition of the reinforced soil outside the receiving tunnel entrance was continuously monitored. Once it was determined that there was basically no open water, the diaphragm wall was immediately broken.

[0046] Breaking time, layered segment construction, not directly from the underground continuous wall skin protection layer to the reinforcement; if the underground continuous wall surface leakage, stop breaking, promptly identify the cause, and take the reinforcement measures, the wall surface dry or no leakage, can continue to break;

[0047] S3, receiving frame and water stop device installation: after the receiving hole door is removed, the receiving hole door position is measured and confirmed, the pipe jacking machine receiving frame is installed according to the actual pipe jacking machine elevation, and the water stop device is installed at the receiving hole door;

[0048] The receiving frame includes a receiving base and a guide device, the receiving base includes a concrete guide table, a 32#a channel steel and a P43 guide rail, the guide table adopts C30 concrete, the guide table reinforcement adopts Φ16 main reinforcement and Φ8@300 stirrup, the channel steel anchor uses Φ20@400 anchor reinforcement, and the center axis of the receiving base is consistent with the tunnel design axis; Two guide devices are arranged at the bottom of the receiving hole door, the guide device is 5mm lower than the bottom of the pipe jacking machine head, and the receiving base is 5mm lower than the guide device;

[0049] The water stop device includes two annular steel plates and a wire, the annular steel plate is 10-30mm higher than the outer wall of the pipe joint, the thickness is 3mm, three struts are arranged between the two annular steel plates, a 10mm high notch is cut at the position corresponding to each triangular strut, and the wire is inserted between the two annular steel plates, the height of the wire is 25cm, and two grouting holes are reserved on the upper, lower, left and right of the hole door steel ring as subsequent emergency grouting holes;

[0050] S4, soil and water backfilling in the receiving well: after the receiving frame and the water stop device are installed, immediately backfill soil and water into the receiving well, so that the water and soil pressure inside and outside the receiving well reaches balance;

[0051] When the receiving hole door breaking is completed, immediately backfill soil and water in the receiving well, backfill cement modified soil, in the embodiment, the receiving well has a net size of 11.2m in the longitudinal direction, 12.87m in the transverse direction, 20.9m in depth, and 1.4m in bottom plate thickness; The receiving hole door reinforcement adopts φ850@600 triaxial mixing pile reinforcement + vertical freezing reinforcement, the triaxial mixing pile reinforcement has a longitudinal length of 6m, the hole door reinforcement has a width of 15.1m, and the freezing reinforcement has a longitudinal length of about 3m, in the embodiment, the backfilling height of the cement modified soil is calculated to be 3m above the pipe jacking machine according to the following calculation formula, and then clear water is recirculated to 2m below the ground surface;

[0052]

[0053]

[0054] Synchronization of the pipe jacking machine left and right side of each 2 rows of the remaining frozen pipe outside the frozen pipe for the circulation of hot brine thawing and pulling out, frozen pipe specific pull-out method: use preheated hot brine to force thawing of the frozen hole, after 5-8 minutes of hot brine circulation thawing, use the car to pull out the thawed frozen pipe, when the frozen pipe is heated to be able to twist appropriately, it can be pulled out, when pulling out about 0.5m, stop circulating hot brine, use compressed air to discharge the salt water in the pipe, and pull out the frozen pipe quickly;

[0055] S5, the pipe jacking machine jacks to the position: after the water and soil backfilling is completed, the pipe jacking machine is out of the hole for the second time, and jacks to the designed position;

[0056] When the pipe jacking machine cutter tip is 6m away from the receiving hole door, start to stop the first pipe section grouting, and gradually move the grouting position backward in the subsequent jacking process, to ensure that a perfect 6m soil plug is formed before the pipe jacking into the hole, to avoid the sudden increase of the pipe section peripheral frictional force caused by the large loss of the friction reducing mud during the hole entering process;

[0057] The pipe jacking machine is pushed into the backfilling soil in the receiving well, and the pushing speed is controlled at 5-10mm / min; until the first pipe section protrudes 50cm from the receiving hole door, the pushing is stopped, the support is set at the predetermined position of the receiving frame track to prevent the pipe jacking machine from sliding forward, and the first longitudinal tensioning member is used to prevent the pipe section from loosening, the first longitudinal tensioning member is pre-buried in the temporary steel plate on the top plate and the bottom plate of the first five pipe sections, and the adjacent pipe sections are prevented from loosening after the jacking force is removed by welding the pull rod with the pre-buried steel plate, and the first longitudinal tensioning member is removed after the construction is completed;

[0058] The first to tenth pipe sections are injected with 1:1 double liquid slurry through 1 inch holes for slurry solidification, to block the possible water seepage channels between the pipe sections and the receiving hole door, at this time, the left and right two rows of frozen pipes of the pipe jacking machine are pulled out, if the pipe jacking machine enters the receiving hole door and serious leakage occurs at the hole door position, pour underwater concrete into the receiving well for counterpressure in time, and supplement the friction reducing grouting amount of the friction reducing grouting hole in time;

[0059] S6, water pumping and soil cleaning in the receiving well and hole door sealing: start pumping water in the receiving well, and clean the backfilling soil layer by layer, and seal the receiving hole door at the same time as the cleaning progress;

[0060] Check the slurry solidification effect injected in S5, if the effect is good, start pumping water in the receiving well, and clean the backfilling soil layer by layer, closely observe whether there is water outburst in the soil body during the cleaning of the backfilling soil, if there is outburst, stop cleaning, continue to grout the wall thickness of the first to tenth pipe sections, if there is no outburst phenomenon, continue to clean layer by layer, and seal the receiving hole door at the same time as the cleaning progress;

[0061] S7, separation of the pipe jacking machine and the pipe section: the pipe jacking machine is separated from the first pipe section, is translated to the hoisting hole position, is disassembled and is hoisted out of the well;

[0062] The soil in the soil pressure chamber of the machine head and the screw machine is removed; the hydraulic oil pipe and the electric wire cable related to the cutter head and the pipe jacking machine system are removed; the two screw conveyors are removed; the machine head is disconnected from the pipe joint by the telescopic deviation correction jack and the added cushion block, the machine head is pushed out as a whole, and is smoothly landed on the receiving platform; the pipe jacking machine is pushed to the receiving hoisting hole position by a small jack and a steel top; the front and rear shells and the upper and lower shells of the pipe jacking machine are disassembled; the machine head of the pipe jacking machine is hoisted out of the well by the truck crane in blocks;

[0063] S8, relay closure: after the pipe jacking is completed, the relay is closed and filled with concrete construction;

[0064] When the pipe jacking machine starts to enter the receiving well, the relay cylinder top is fully retracted to the minimum position, so that the front and rear shell pipe openings of the relay are connected and tightly connected.

[0065] After the pipe jacking construction is completed, the jacking oil cylinder is removed, the double liquid cement slurry is pressed into the relay from high to low from the relay P2 grouting hole to the outside of the relay, replacing the thixotropic slurry that plays a role in reducing resistance when the pipe is jacked, filling the gap between the front and rear shells, if there is leakage, secondary grouting is performed, after grouting is completed, grouting hole sealing is done, grouting should be uniform and dense, the outside of the relay needs to be uniformly wrapped, to ensure that underground water outside the pipe cannot seep in, to create a relatively dry environment for the subsequent welding work of the relay closure;

[0066] The pipe jacking equipment in the relay is removed from front to back, the relay circuit, control system, oil pump station, oil circuit, jack, etc. are removed in sequence; the sequence of removing each relay is: first the top, then the two sides, and finally the bottom; the front and rear shell connecting plates of the relay are welded, the annular inner lining plate of the rear section is welded with the front section shell, and the movable part of the relay is completely closed; the surface oil stains of the relay are removed with a detergent, the steel mesh is installed, the formwork is installed, and the micro-expanding concrete is poured in three times according to the sequence of first the bottom, then the two sides, and finally the bottom;

[0067] The second longitudinal tensioning member passes through the prestressed tendon through the prestressed duct pre-buried inside all rectangular pipe joints, and prestressed tensioning is performed after the pipe jacking is completed;

[0068] S9, pipe joint peripheral slurry solidification: using the system and pipeline of pressure injection thixotropic slurry to solidify the cement slurry;

[0069] Slurry solidification method: after being received in place, the method of grouting from both ends to the middle is adopted;

[0070] The injection sequence is as follows: in this embodiment, there are 183 pipe sections in the whole line, and the slurry is cured in sections, each section including 5 pipe sections, and there are 37 sections in total; when injecting the slurry, first, the two injection holes at the bottom of the first to fifth pipe sections and the 183rd to 179th pipe sections are injected, then the two injection holes at the two sides of the first to fifth pipe sections and the 183rd to 179th pipe sections are injected, and finally, the two injection holes at the top of the first to fifth pipe sections and the 183rd to 179th pipe sections are injected; the injection is repeated in this sequence until the whole line is completed; after the curing of the slurry is completed, the main channel slurry pipe, the inner-arc slurry pipe and the ball valve are cleaned in situ to prevent the slurry from being solidified and blocked;

[0071] The slurry curing parameters are as follows: the water-cement ratio of the cured cement slurry is 0.7-0.8, the slurry specific gravity is 1.26-1.28, the injection pressure is 0.3-0.5 MPa, and the injection amount is greater than or equal to 1.02 m 3 / section;

[0072] During the injection process, the road surface and the pipeline are monitored, the injection pressure and the injection amount are strictly controlled, and the pressure is prevented from being too large or too small to cause adverse disturbance, and the tunnel monitoring is strengthened.

[0073] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent scheme using the content of the present application, directly or indirectly applied to other related technical fields, is also within the patent protection scope of the present application.

Claims

1. A method for receiving a large-section rectangular pipe jacking in a water-rich sand layer, characterized in that, The method comprises the following steps: S1, receiving preparation: the pipe jacking machine is a certain distance away from the receiving well as a pipe jacking receiving section, and the pipe jacking receiving is prepared to start; S2, receiving hole portal removal: after the receiving hole portal reinforcement reaches the design requirement and is accepted, the surrounding structure in the receiving hole portal range is removed, and the surrounding structure is removed under the condition that the reinforcement is qualified during the removal; S3, receiving frame and water stop device installation: after the receiving hole portal is removed, the receiving hole portal position is measured and confirmed, the pipe jacking machine receiving frame is installed according to the actual pipe jacking machine elevation, and the water stop device is installed at the receiving hole portal; S4, soil and water backfilling in the receiving well: after the receiving frame and water stop device installation are completed, the soil and water are backfilled into the receiving well, so that the water and soil pressure inside and outside the receiving well reaches balance; S5, pipe jacking machine jacking to position: after the soil and water backfilling is completed, the pipe jacking machine is out of the hole for the second time, and jacked to the design position; S6, water pumping and soil cleaning in the receiving well and hole portal sealing: the water in the receiving well is pumped out, and the backfilled soil is cleaned layer by layer, and the receiving hole portal is sealed at the same time as the cleaning progress; S7, pipe jacking machine and pipe joint separation: the pipe jacking machine and the first pipe joint are separated, are translated to the hoisting hole position, are disassembled and are hoisted out of the well; S8, relay interval closure: after the pipe jacking is completed, the relay interval is closed and filled with concrete construction; S9, pipe joint periphery slurry solidification: the system and pipeline of pressure injection thixotropic mud are used for cement slurry solidification.

2. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1, characterized in that, In S1, the receiving hole portal reinforcement adopts a combined reinforcement measure of triaxial mixing pile and vertical freezing, the freezing reinforcement mode is slab freezing wall soil reinforcement, the freezing wall is close to the underground continuous wall of the receiving well, the actual active freezing days are determined according to the temperature field monitoring of the engineering site, after the freezing is completed, 9 meter-shaped probe holes are drilled at the receiving hole portal by using a water drill, the probe hole depth is more than 100mm of the underground continuous wall, the probe hole diameter is 50mm, a temperature measuring wire is installed in the probe hole, the probe hole temperature is measured, and the freezing effect of the receiving hole portal is evaluated.

3. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S2, 9 observation holes are drilled at the receiving hole portal position before the underground continuous wall is removed, the observation hole diameter is 80mm, the drilling depth ensures that the reinforced soil is drilled, a ball valve is installed at the hole position, and the outside of the ball valve is sealed with quick-drying cement, before the underground continuous wall is removed, the ball valve is opened every certain time to observe whether water flows out, the reinforced soil condition outside the receiving hole portal is continuously observed, and after it is judged that there is basically no water, the underground continuous wall is immediately removed.

4. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S3, the receiving frame comprises a receiving base and a guide device, the receiving base comprises a concrete guide table, a 32#a channel steel and a P43 guide rail, the guide table adopts C30 concrete, the guide table reinforcement adopts Φ16 main reinforcement and Φ8@300 stirrup reinforcement, the channel steel anchoring adopts Φ20@400 anchor reinforcement, and the central axis of the receiving base is consistent with the tunnel design axis; two guide devices are arranged at the bottom of the receiving hole portal, the guide device is 5mm lower than the bottom of the pipe jacking machine head, and the receiving base is 5mm lower than the guide device.

5. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S3, the water stop device comprises two annular steel plates and a wire, the annular steel plates are 10-30 mm higher than the outer wall of the pipe section, and the thickness is 3 mm, a triangular support is arranged between the two annular steel plates, a 10 mm high incision is cut at a position corresponding to each triangular support, and the wire is inserted between the two annular steel plates, the height of the wire is 25 cm, and two grouting holes are reserved on the upper, lower, left and right of the hole door steel ring as subsequent emergency grouting holes.

6. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S4, the remaining frozen pipes outside the left and right sides of the pipe jacking machine are simultaneously subjected to circulating hot brine thawing and are pulled out, and the frozen pipes are pulled out in the following manner: the frozen hole is forcibly thawed by using preheated hot brine, after 5-8 minutes of hot brine circulation thawing, the thawed frozen pipe is pulled out by using a car crane, when the frozen pipe is heated to be able to be appropriately twisted, the pipe is pulled out, when 0.5 m is pulled out, the circulating hot brine is stopped, the salt water in the pipe is discharged by using compressed air, and the frozen pipe is quickly pulled out.

7. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S5, when the distance between the pipe jacking machine cutter tip and the receiving hole door is 6 m, the grouting of the first pipe section is stopped, and the grouting position is gradually moved backward in the subsequent jacking process, so that a perfect 6 m soil plug is formed before the pipe jacking into the hole.

8. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S5, the pipe jacking machine is pushed into the backfill soil in the receiving well, and the pushing speed is controlled to be 5-10 mm / min; until the first pipe section protrudes from the receiving hole door by 50 cm, the pushing is stopped, a support is arranged at a predetermined position on the track of the receiving frame to prevent the pipe jacking machine from sliding forward, and the first longitudinal tensioning member is used to prevent the pipe section from loosening.

9. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S8, when the pipe jacking machine starts to enter the receiving well, the relay interval oil cylinder is retracted to the minimum position, so that the front and rear shell pipe openings of the relay interval are connected and tightly fit; After the jacking construction is completed, before the jacking oil cylinder is removed, the double liquid cement slurry is pressed into the relay interval from high to low through the relay interval grouting hole, the thixotropic slurry that plays a role in reducing resistance during pipe jacking is replaced, the gap between the front and rear shells is filled, secondary grouting is performed if there is leakage, and the grouting hole is sealed after grouting is completed; The jacking equipment in the relay interval is removed from front to back, and the relay interval circuit, control system, oil pump station, oil circuit, jack, etc. are removed in sequence; the sequence of removing each relay interval is: first the top, then the two sides, and finally the bottom; the front and rear shell connecting plates of the relay interval are welded, the ring-shaped inner lining plate of the rear section is welded with the front section shell, and the movable part of the relay interval is completely closed; the surface oil stains of the relay interval are wiped off with a detergent, the steel mesh is installed, the formwork is installed, and the micro-expanding concrete is poured in three times according to the sequence of first the bottom, then the two sides, and finally the bottom; The second longitudinal tensioning member is used to pass through the pre-stressed tendon through the pre-stressed hole channel pre-buried in all rectangular pipe sections, and the pre-stressed tendon is tensioned after the pipe jacking is completed.

10. The water-rich sand layer large-section rectangular pipe receiving construction method according to claim 1 or 2, characterized in that, In S9, after receiving the bit, the grouting from both ends to the middle is adopted; the water-cement ratio of the solidified cement slurry is 0.7-0.8, the slurry specific gravity is 1.26-1.28, the grouting pressure is 0.3-0.5 MPa, and the grouting amount is ≥1.02 m 3 / section.

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