Rectangular pipe jacking rock stratum pretreatment method

Abstract

The invention provides a rectangular pipe-jacking rock stratum pretreatment method which comprises the following steps: after preparation before construction is completed, assembling and debugging a jumbolter, and then drilling, positioning and paying off to ensure the accuracy and stability of a drilling position; then a phi100 anchor rod drilling machine is used for conducting horizontal drilling and crushing on the moderately-weathered rock mass, quincunx arrangement is adopted, the center distance is 300 mm * 300 mm, drilling is started from two rows of hole sites at the bottom, then blind area hole site drilling is conducted, and finally drilling is conducted on the position of a cutter head; the method comprises the following steps: after constructing and forming a hole, blowing medium-coarse sand into the hole by using a high-pressure sand blowing technology, filling a drilling gap and preventing sedimentation, finally, before jacking of a jacking pipe, injecting water into the hole, softening medium-weathered sandstone in advance, and reducing resistance and torque during pushing of the jacking pipe, after the steps are completed, starting jacking construction of the jacking pipe, and meanwhile, according to monitoring data and construction experience, determining whether the jacking pipe is pushed or not. The propelling speed and strength of the pipe jacking machine are adjusted, and safe and efficient pipe jacking construction is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering, and in particular relates to a rectangular jacking pipe rock formation pretreatment method. Background Art

[0002] As the contradiction between supply and demand of ground space capacity becomes increasingly prominent, the demand for underground space development such as underground passages, integrated pipe corridors, underground parking lots and underground shopping malls is increasing. The country vigorously develops underground and intensive transportation and municipal public facilities and arranges some public buildings in underground space. This is of great significance to effectively expand space supply, improve urban efficiency, reduce ground occupation, and protect ground landscape and environment. In the past, the construction of underground structures mostly adopted the open excavation construction method. This method has many disadvantages: construction will not only interrupt traffic and affect the environment, but also may cause damage to nearby buildings; for underground space development projects with large burial depths, not only will the construction cost increase sharply, but the risk of construction operations will also increase.

[0003] Moderately weathered rock strata refer to geological strata that have undergone moderate weathering. Their physical properties are between those of unweathered rock and deeply weathered rock. Their structural stability, settlement, deformation and stability issues will all affect construction.

[0004] The use of rectangular pipe jacking construction can effectively avoid the above problems. In addition to constructing working shafts and receiving shafts by local excavation, it can be constructed under conditions such as no closed traffic, no relocation of pipelines, low noise and less dust. Compared with circular shield tunneling, its space utilization rate can be increased by 20%, thereby greatly reducing construction costs and bringing new opportunities for the development of urban underground space. Summary of the invention

[0005] In view of the above problems, the present invention proposes a rectangular jacking pipe rock formation pretreatment method, which is suitable for underground jacking engineering construction where large-section rectangular jacking pipes pass through weathered rock formations, the surrounding environment is complex, and the settlement amount needs to be strictly controlled within the construction influence range.

[0006] The present invention is achieved through the following technical solutions:

[0007] A rectangular jacking pipe rock formation pretreatment method: the method specifically comprises the following steps:

[0008] Step 1: Conduct pre-construction preparations, conduct site surveys and assessments, develop detailed construction plans and emergency plans, and establish a monitoring system to monitor construction progress and safety risks throughout the entire process;

[0009] Step 2: Assembly and commissioning of the anchor drilling rig. After the anchor drilling rig is hoisted into the well, it is immediately assembled and commissioned without load. Drilling construction can only be officially started after confirming that the operating performance indicators of the anchor drilling rig meet the construction requirements.

[0010] Step 3, drilling positioning and layout: according to the design requirements, use measuring equipment to accurately lay out the drilling points to ensure the accuracy and stability of the drilling positions;

[0011] Step 4, drilling and crushing: Use a Φ100 anchor drilling rig to perform horizontal drilling and crushing on the medium-weathered rock mass, using a plum blossom arrangement with a center spacing of 300mm×300mm. Start drilling from the bottom two rows of holes, then drill the blind area holes, and finally drill the cutter head position;

[0012] Step 5: drilling, according to the crushing effect of step 4, drilling is performed to ensure that the design slope of the jacking channel meets the requirements;

[0013] Step 6, high-pressure sand blowing filling in the hole: After the hole is constructed, medium-coarse sand is blown into the hole using high-pressure sand blowing technology to fill the borehole gap and prevent settlement. The sand blowing amount and pressure are adjusted according to the surface settlement and rock formation strength to ensure that the hole is filled evenly and densely;

[0014] Step 7, water injection in the hole before the jacking pipe is pushed in: Before the jacking pipe is pushed in, water is injected into the hole to soften the moderately weathered sandstone in advance, reduce the resistance and torque when the jacking pipe is pushed in, control the water injection amount and time, ensure that the rock is fully softened, and avoid instability caused by excessive softening;

[0015] Step 8: Pipe jacking construction: After completing the above steps, start pipe jacking construction.

[0016] Adjust the propulsion speed and force of the pipe jacking machine according to monitoring data and construction experience to ensure safe and efficient pipe jacking construction;

[0017] Step 9, construction monitoring and adjustment:

[0018] Increase monitoring points and monitoring frequency to monitor key parameters in the construction process in real time.

[0019] Adjust the construction plan in time according to the monitoring data to ensure construction safety and quality;

[0020] Step 10: Post-construction evaluation and maintenance

[0021] After the construction is completed, the project quality assessment is carried out to ensure that the expected construction effect is achieved.

[0022] Develop a long-term maintenance plan to regularly inspect and maintain the pipe jacking channel to ensure its long-term stability and functionality.

[0023] Furthermore, in step 1,

[0024] Before the anchor drilling rig drilling and obstacle removal construction, the construction personnel, machines and materials must be in place;

[0025] Before construction, the bored piles at the hole locations need to be drilled with a water drill, with a length sufficient to penetrate the retaining piles. After the construction is completed, the entire tunnel gate should be promptly removed to ensure the smooth start of the pipe jacking machine.

[0026] Furthermore, in step 2,

[0027] The specific operation of no-load debugging is as follows:

[0028] Step 2.1, start the pump station motor: put the operating handles on the main engine in the non-working position. At this time, the indicated pressure of the pressure gauge on the pump station should not exceed 2Mpa, the oil temperature in the oil tank is above 200℃, and the liquid level is in the middle and upper part of the oil mark;

[0029] Step 2.2, outrigger idle operation: slowly turn the outrigger control handle to the raised position, and the outrigger cylinders at all levels should extend smoothly; turn it to the lowered position, and the cylinders at all levels should retract smoothly;

[0030] Step 2.3, motor idling: press the rotary motor control trigger, the drill rig spindle should have a controlled operation from slow to fast, and at the same time turn the outrigger control handle. The combined actions of the two should not interfere with each other and operate flexibly.

[0031] Furthermore, in step 3,

[0032] The anchor construction is planned to use a track-type anchor drilling rig. In order to ensure that the depression angle and azimuth angle of the anchor hole axis during the construction process and after the hole is formed meet the design requirements, the accuracy and stability of the drilling rig must be ensured, and the axis of the hole-opening drill must be strictly checked to see if it is consistent with the axis of the designed anchor hole.

[0033] The accuracy specifically includes:

[0034] ① Adjust the elevation of the contact point between the vertical axis of the drilling rig and the slope surface to be consistent with the calibrated hole position;

[0035] ② Adjust the axis of the vertical axis of the drilling hole to keep it consistent with the depression angle and azimuth angle of the designed center axis of the anchor hole;

[0036] ③ The technical personnel shall measure and calibrate the axis of the drilling tool to make it consistent with the center axis of the anchor hole before drilling the hole;

[0037] The stability specifically includes:

[0038] ① Use clamping pipes to firmly secure the drilling rig;

[0039] ② Test-run the drilling rig, calibrate the axis of the drilling tool and the center axis of the anchor hole again to make them consistent, and tighten the fastening screw;

[0040] ③ The stability of the drilling rig must be ensured at all times during the drilling process;

[0041] ④ During the construction process, set up a protector to ensure the drilling direction.

[0042] Furthermore, in step 4, the points are measured and placed strictly according to the required position and elevation, and marked and indicated with the drilling number;

[0043] After the no-load test is normal, insert the hexagonal drill rod into the hexagonal hole of the drill rod joint, slowly press the motor control trigger to make the drill rod rotate slowly, turn the propulsion mechanism control handle to a smaller angle, slowly raise the legs to make the drill bit contact with the top plate, press the motor trigger, and the hole is completed after drilling about 20mm;

[0044] The hole position deviation is ±10mm in the horizontal direction and ±5mm in the vertical direction. The allowable inclination angle of the drilling hole is less than 1%. The bottom edge and bottom R angle of the portal steel ring and the blind area are densely arranged in two rows, and the hole size is 100mm; pre-treat other parts, the hole size is 100mm, and the points are arranged in a plum blossom shape with a center spacing of 300mm*300mm;

[0045] The designed slope of the jacking channel is 0.5%, the crushing slope of the drill pipe is 1%, and the crushing slope of the bottom two rows is controlled at 5% to increase the crushing surface;

[0046] The slope is controlled by measuring with a level and each section of the anchor is reviewed to ensure the accuracy of the treatment range and to ensure that the rock within the jacking pipe range is fully crushed.

[0047] Furthermore, in step 5,

[0048] The drilling method includes water drilling and pneumatic down-the-hole impact drilling.

[0049] Water drilling uses water flow as the cutting medium and is suitable for drilling holes in hard rock or other difficult-to-drill materials.

[0050] The pneumatic down-the-hole impact drilling uses compressed air as the power source, breaking the rock through the impact force of the impactor, and uses the follow-the-tube technology to maintain the stability and straightness of the borehole;

[0051] At the same time, the drilling speed should be uniform and strictly controlled to ensure that the verticality and diameter of the hole are consistent; the anchor hole adopts the follow-pipe impact drilling process, and the casing can only be pulled out after the anchor rod is lowered into the hole.

[0052] Beneficial effects of the present invention

[0053] Compared with traditional drilling and blasting methods, mechanical crushing methods, chemical crushing methods, etc., the present invention has at least the following technical effects:

[0054] (1) Improve construction efficiency:

[0055] By using a Φ100 anchor drilling rig for horizontal drilling and crushing, the rock formation can be pre-processed more quickly. Compared with the traditional vertical drilling method, this method can reduce useless engineering workload and improve construction efficiency.

[0056] (2) Reduce the impact on the environment:

[0057] High-pressure sand blowing technology can effectively reduce surface subsidence and other environmental impacts by blowing sand to fill broken holes. This is especially important for construction in central urban areas because it reduces interference with surrounding buildings and traffic.

[0058] (3) Enhance construction safety:

[0059] Injecting water into the hole before the jacking pipe is advanced to soften the moderately weathered sandstone can reduce the resistance and torque during the advancement of the jacking pipe, reduce construction risks, and ensure the safety and controllability of the construction process.

[0060] (4) Better construction quality:

[0061] Increasing monitoring points and monitoring frequency for the entire process can ensure that every link in the construction process is effectively controlled, thereby improving the overall construction quality.

[0062] (5) Reduce construction costs:

[0063] The method of the present invention helps to reduce the overall construction cost by reducing unnecessary engineering workload and improving construction efficiency. At the same time, it also reduces potential risk costs by reducing environmental impact and improving safety.

[0064] (6) Strong adaptability:

[0065] The method of the present invention is suitable for underground pipe jacking engineering construction where a large-section rectangular pipe jacking passes through a medium-weathered rock layer, especially in situations where the surrounding environment is complex and the settlement amount needs to be strictly controlled, and shows strong adaptability and practicability.

[0066] In summary, the present invention is suitable for the construction of underground pipe jacking projects where large-section rectangular pipe jacking passes through weathered rock formations, the surrounding environment is complex, and the settlement needs to be strictly controlled within the construction influence range; it has obvious advantages in improving construction efficiency, reducing environmental impact, enhancing construction safety, optimizing construction quality, reducing construction costs, and strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a schematic diagram of the horizontal drilling arrangement of the present invention.

[0068] Figure 2 This is a schematic diagram of the processing range of the present invention.

[0069] Figure 3This is an example diagram of hole placement in the embodiment.

[0070] Figure 4 This is an example diagram of drilling and crushing in the embodiment.

[0071] Figure 5 This is an example diagram of adding drilling holes in the embodiment.

[0072] Figure 6 This is an example diagram of drilling and crushing in the embodiment.

[0073] Figure 7 This is an example diagram of hole depth acceptance in the embodiment.

[0074] Figure 8 This is an example diagram of a sand blowing cloth tube in the embodiment.

[0075] Fig. 9 This is an example diagram of artificial sand addition in the sand blowing equipment in the embodiment.

[0076] Fig.10 This is an example diagram of sand blowing using high-pressure equipment in the tunnel in the embodiment.

[0077] Fig.11 This is an example diagram of sand blowing and sealing at the tunnel entrance in the embodiment.

[0078] Fig.12 This is an example diagram of the final cleanup in the embodiment.

[0079] Fig.13 This is an example diagram of surrounding settlement monitoring in the embodiment. DETAILED DESCRIPTION

[0080] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0081] A rectangular jacking rock formation pretreatment method: the main material required is medium-coarse sand. The required machinery is an anchor drill, an air compressor, a plastic pipe, and a crane.

[0082] Combination Figures 1 to 13 , the method specifically comprises the following steps:

[0083] Step 1: Conduct pre-construction preparations, conduct site surveys and assessments, develop detailed construction plans and emergency plans, and establish a monitoring system to monitor construction progress and safety risks throughout the entire process;

[0084] Before the anchor drilling rig drilling and obstacle removal construction, the construction personnel, machines and materials must be in place;

[0085] Before construction, the bored piles on the pre-treated holes need to be drilled with water drills. Drilling with water drills can effectively reduce friction and heat during the drilling process and reduce the impact on surrounding structures. The length of the holes can be enough to penetrate the retaining piles. (The holes need to be drilled deep into the other side of the retaining piles to create conditions for the start of the pipe jacking machine.) Because the existence of the tunnel gate may hinder the smooth start and advancement of the pipe jacking machine, in order to ensure that the pipe jacking machine can enter the underground passage without obstacles and start the pipe jacking construction, the tunnel gate should be removed as a whole in time after the pre-treatment construction is completed to ensure the smooth start of the pipe jacking machine.

[0086] Ensure that the pipe jacking machine can smoothly enter the underground passage from the starting well and start the subsequent pipe jacking construction work. By drilling holes and breaking the door, obstacles can be cleared for the advancement of the pipe jacking machine, while reducing the impact on the surrounding structure and environment.

[0087] Step 2: Assembly and commissioning of the anchor drilling rig. After the anchor drilling rig is hoisted into the well, it is immediately assembled and commissioned without load. Drilling construction can only be officially started after confirming that the operating performance indicators of the anchor drilling rig meet the construction requirements.

[0088] The specific operation of no-load debugging is as follows:

[0089] Step 2.1, start the pump station motor: put the operating handles on the main engine in the non-working position. At this time, the indicated pressure of the pressure gauge on the pump station should not exceed 2Mpa, the oil temperature in the oil tank is above 200℃, and the liquid level is in the middle and upper part of the oil mark;

[0090] Step 2.2, outrigger idle operation: Slowly turn the outrigger control handle to the up position, and the outrigger cylinders at all levels should extend smoothly. Turn it to the down position, and the cylinders at all levels should retract smoothly;

[0091] Step 2.3, motor idling: press the rotary motor control trigger, the drill rig spindle should have a controlled operation from slow to fast, and at the same time turn the outrigger control handle. The combined actions of the two should not interfere with each other and operate flexibly.

[0092] Step 3, drilling positioning and layout: according to the design requirements, use measuring equipment to accurately lay out the drilling points to ensure the accuracy and stability of the drilling positions;

[0093] The anchor construction is planned to use a track-type anchor drilling rig. In order to ensure that the depression angle and azimuth angle of the anchor hole axis during the construction process and after the hole is formed meet the design requirements, the accuracy and stability of the drilling rig must be ensured, and the axis of the hole-opening drill must be strictly checked to see if it is consistent with the axis of the designed anchor hole.

[0094] The accuracy specifically includes:

[0095] ① Adjust the elevation of the contact point between the vertical axis of the drilling rig and the slope surface to be consistent with the calibrated hole position;

[0096] ② Adjust the axis of the vertical axis of the drilling hole to keep it consistent with the depression angle and azimuth angle of the designed center axis of the anchor hole;

[0097] ③ The technical personnel shall measure and calibrate the axis of the drilling tool to make it consistent with the center axis of the anchor hole before drilling the hole;

[0098] The stability specifically includes:

[0099] ① Use clamping pipes to firmly secure the drilling rig;

[0100] ② Test-run the drilling rig, calibrate the axis of the drilling tool and the center axis of the anchor hole again to make them consistent, and tighten the fastening screw;

[0101] ③ The stability of the drilling rig must be ensured at all times during the drilling process;

[0102] ④ During the construction process, set up a protector to ensure the drilling direction.

[0103] Step 4, drilling and crushing: Drilling and crushing are used to weaken the rock layer to create conditions for the jacking of the pipe. Use a Φ100 anchor drill to drill and crush the medium-weathered rock mass horizontally, using a plum blossom arrangement with a center spacing of 300mm×300mm. Drill holes from the bottom two rows of holes, then drill blind holes, and finally drill holes at the cutterhead position; this ensures the initial formation of the jacking channel and provides a basis for subsequent hole-forming operations.

[0104] Strictly measure and place points according to the required position and elevation, and mark them and indicate the drilling number;

[0105] After the no-load test is normal, insert the hexagonal drill rod into the hexagonal hole of the drill rod joint, slowly press the motor control trigger to let the drill rod rotate slowly (or do not perform this operation and let the drill rod support the top plate first), the propulsion mechanism control handle rotates a small angle, the legs rise slowly, let the drill bit contact the top plate, press the motor trigger, and the hole is completed after drilling about 20mm;

[0106] The hole position deviation is ±10mm in the horizontal direction and ±5mm in the vertical direction. The allowable inclination angle of the drilling hole is less than 1%. The bottom edge and bottom R angle of the portal steel ring and the blind area are densely arranged in two rows, and the hole size is 100mm; pre-treat other parts, the hole size is 100mm, and the points are arranged in a plum blossom shape with a center spacing of 300mm*300mm;

[0107] The success of the pipe jacking in this project depends entirely on the pre-treatment and crushing effect of the medium-weathered muddy siltstone. The treatment range must be larger than the jacking range of the pipe jacking machine to ensure smooth jacking. The design slope of the pipe jacking channel is 0.5%, the drill pipe crushing slope is 1%, and the crushing slope of the bottom two rows is controlled at 5% to increase the crushing surface;

[0108] The slope is controlled by measuring with a level and each section of the anchor is reviewed to ensure the accuracy of the treatment range and to ensure that the rock within the jacking pipe range is fully crushed.

[0109] Step 5, drilling, is performed based on the crushing effect of step 4 to ensure that the designed slope of the jacking pipe channel meets the requirements; it also involves cleaning the gravel in the borehole, adjusting the size and shape of the borehole, etc. to ensure that the jacking pipe can pass smoothly.

[0110] The drilling method includes water drilling and pneumatic down-the-hole impact drilling.

[0111] Water drilling uses water flow as the cutting medium and is suitable for drilling holes in hard rock or other difficult-to-drill materials.

[0112] Water drilling technology can reduce friction and heat during the drilling process, thereby improving drilling efficiency and protecting the material around the drill hole from thermal damage.

[0113] Drilling: After the hole position is determined, turn on the water valve switch (if the rock is hard, use an impact drill to break it), the rotary motor rotates at full speed, and according to the hardness of the rock, adjust the angle of the propulsion mechanism control handle to achieve the best match between the propulsion speed and the rotary torque to achieve efficient drilling.

[0114] Connect the drill rod: After the first drill rod is completed, close the water valve. When the drill rod is in the rotating state, turn the control handle of the propulsion mechanism in the opposite direction, the legs fall back, the drill rod is pulled out of the hole, and the completed drill rod is inserted into the hole to continue drilling.

[0115] Before the second drilling, the installation of the drilling rig needs to be retested. The installation quality of the drilling rig not only affects the quality of the drilling, but also affects the construction progress and personnel safety. The installation should be "straight, flat, stable and solid" to ensure that the drilling rig does not swing or shift after being stressed. After the drilling rig is installed, a comprehensive quality inspection is carried out to check the azimuth, inclination, horizontality and the drop difference of the drilling bit. After the inspection is qualified, a test run can be carried out, and the formal hole-making operation can only be started after the test run is qualified.

[0116] Pneumatic down-the-hole impact drilling uses compressed air as the power source, breaking the rock through the impact force of the impactor, and uses the drilling tube technology to maintain the stability and straightness of the borehole.

[0117] Pneumatic down-the-hole impact drilling is suitable for various formations, especially when rapid drilling and keeping the hole clean are required;

[0118] ①Process parameters

[0119] Drilling pressure: When drilling, make the impactor close to the wall, impact with low pressure, and advance steadily and slowly. During the drilling process, Pf=2~4kN.

[0120] ②Speed

[0121] (A) Opening speed: n=0.

[0122] (B) Drilling speed: n*50rpm.

[0123] (C) Air volume: Qwind = 9~20m3 / min, wind pressure: 120~150kPa.

[0124] ③Clear the hole.

[0125] Use >0.8MPa compressed air to punch holes and remove slag to ensure that the remaining rock debris at the bottom of the hole meets the design requirements.

[0126] ④Precautions

[0127] The drilling speed should be uniform and strictly controlled to ensure that the verticality and diameter of the hole are consistent. The anchor hole is drilled using the pipe impact drilling process, and the casing can only be pulled out after the anchor rod is lowered into the hole.

[0128] Step 6, high-pressure sand blowing filling in the hole: After the hole is constructed, use high-pressure sand blowing technology to blow medium and coarse sand into the hole to fill the borehole gaps and prevent subsidence. According to the surface subsidence and rock formation strength, adjust the sand blowing amount and pressure to ensure that the hole is filled evenly and densely; thereby providing stable support for the jacking of the jacking pipe.

[0129] Step 7, water injection in the hole before the jacking pipe is pushed in: Before the jacking pipe is pushed in, water is injected into the hole to soften the moderately weathered sandstone in advance, reduce the resistance and torque when the jacking pipe is pushed in, control the water injection amount and time, ensure that the rock is fully softened, and avoid instability caused by excessive softening;

[0130] Step 8: Pipe jacking construction: After completing the above steps, start pipe jacking construction.

[0131] Adjust the propulsion speed and force of the pipe jacking machine according to monitoring data and construction experience to ensure safe and efficient pipe jacking construction;

[0132] Step 9, construction monitoring and adjustment:

[0133] Increase monitoring points and monitoring frequency to monitor key parameters in the construction process in real time.

[0134] Adjust the construction plan in time according to the monitoring data to ensure construction safety and quality;

[0135] Step 10: Post-construction evaluation and maintenance

[0136] After the construction is completed, the project quality assessment is carried out to ensure that the expected construction effect is achieved.

[0137] Develop a long-term maintenance plan to regularly inspect and maintain the pipe jacking channel to ensure its long-term stability and functionality.

[0138] Example:

[0139] In combination with the construction characteristics of the underground pedestrian crossing in the South Square of Nanjing South Railway Station, pre-treatment was used to break up the weathered rock in advance, and the broken holes were filled with sand. During the process, monitoring was strengthened and construction was guided by information technology. This achieved the purpose of safe production, controlled settlement, and ensured waterproof quality.

[0140] Since the strata distribution in the jacking section of the South Square of Nanjing South Railway Station is a full cross-section rather than a solitary rock protrusion, vertical crushing treatment will produce a lot of useless engineering volume and low work efficiency. In addition, this project is located on the main road of Liuchao Road, so this method is not adopted. Based on the experience of many similar engineering constructions, horizontal crushing treatment in the shaft can achieve an effective treatment effect of more than 95%, without excessive engineering volume and without occupying a large area of ​​road. Therefore, it is planned to use a Φ100 anchor drilling rig to perform horizontal drilling and crushing of the medium-weathered rock strata, reduce the content of large rocks in the strata, ensure smooth excavation of the spiral excavator and the torque of the jacking cutter head; at the same time, reduce the strength of the medium-weathered siltstone at the lower part of the jacking tunnel portal, ensure that the excavation posture of the jacking machine is controllable, and ensure safe and efficient construction and smooth penetration of the jacking.

[0141] In the South Square of Nanjing South Railway Station, according to the longitudinal strength of the jacking line, the properties and integrity of the medium-weathered muddy siltstone. A Φ100 anchor drilling rig was used to horizontally drill and crush the medium-weathered rock mass. The holes were densely arranged in two rows at the bottom of the starting well and the receiving well and in the blind area of ​​the cutter head. In the rest of the medium-weathered rock range, a plum blossom arrangement with a spacing of 300*300mm was adopted.

[0142] First, construct the two rows of holes at the bottom, then the blind area holes, and finally the cutter head position. In order to avoid stringing holes, the skip hole method is adopted, and every other hole is drilled. Medium-coarse sand is blown into the crushing hole at high pressure to avoid settlement.

[0143] Serial number Type of work Number of people Remark 1 Project Manager 1 Responsible for overall organization and coordination 2 Project Chief Engineer 2 Responsible for daily construction technology 3 Full-time safety officer 2 Responsible for on-site safety 4 Monitor 1 Responsible for daily construction management 5 electrician 1 Maintenance and repair of circuit parts 6 Mechanical operator 2 Drilling rig operation and construction 7 General Worker 4 Lifting drilling holes, water pipes and other auxiliary construction 8 Supplies 1 9 Measurement 2 10 total 16

[0144] Table 1 Labor organization table

[0145] The above is a detailed introduction to the rectangular jacking pipe rock formation pretreatment method proposed in the present invention, and the principles and implementation methods of the present invention are explained. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in the field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A rectangular jacking rock formation pretreatment method, characterized in that: The method specifically comprises the following steps: Step 1: Conduct pre-construction preparations, conduct site surveys and assessments, develop detailed construction plans and emergency plans, and establish a monitoring system to monitor construction progress and safety risks throughout the entire process; Step 2: Assembly and commissioning of the anchor drilling rig. After the anchor drilling rig is hoisted into the well, it is immediately assembled and commissioned without load. Drilling construction can only be officially started after confirming that the operating performance indicators of the anchor drilling rig meet the construction requirements. Step 3, drilling positioning and layout: according to the design requirements, use measuring equipment to accurately lay out the drilling points to ensure the accuracy and stability of the drilling positions; Step 4, drilling and crushing: Use a Φ100 anchor drilling rig to perform horizontal drilling and crushing on the medium-weathered rock mass, using a plum blossom arrangement with a center spacing of 300mm×300mm. Start drilling from the bottom two rows of holes, then drill the blind area holes, and finally drill the cutter head position; Step 5: drilling, according to the crushing effect of step 4, drilling is performed to ensure that the design slope of the jacking channel meets the requirements; Step 6, high-pressure sand blowing filling in the hole: After the hole is constructed, medium-coarse sand is blown into the hole using high-pressure sand blowing technology to fill the borehole gap and prevent settlement. The sand blowing amount and pressure are adjusted according to the surface settlement and rock formation strength to ensure that the hole is filled evenly and densely; Step 7, water injection in the hole before the jacking pipe is pushed in: Before the jacking pipe is pushed in, water is injected into the hole to soften the moderately weathered sandstone in advance, reduce the resistance and torque when the jacking pipe is pushed in, control the water injection amount and time, ensure that the rock is fully softened, and avoid instability caused by excessive softening; Step 8: Pipe jacking construction: After completing the above steps, start pipe jacking construction. Adjust the propulsion speed and force of the pipe jacking machine according to monitoring data and construction experience to ensure safe and efficient pipe jacking construction; Step 9, construction monitoring and adjustment: Increase monitoring points and monitoring frequency to monitor key parameters in the construction process in real time. Adjust the construction plan in time according to the monitoring data to ensure construction safety and quality; Step 10: Post-construction evaluation and maintenance After the construction is completed, the project quality assessment is carried out to ensure that the expected construction effect is achieved. Develop a long-term maintenance plan to regularly inspect and maintain the pipe jacking channel to ensure its long-term stability and functionality.

2. The rectangular jacking pipe rock formation pretreatment method according to claim 1 is characterized by: In step 1, Before the anchor drilling rig drilling and obstacle removal construction, the construction personnel, machines and materials must be in place; Before construction, the bored piles at the hole locations need to be drilled with a water drill, with a length sufficient to penetrate the retaining piles. After the construction is completed, the entire tunnel gate should be promptly removed to ensure the smooth start of the pipe jacking machine.

3. The rectangular jacking pipe rock formation pretreatment method according to claim 2 is characterized in that: In step 2, The specific operation of no-load debugging is as follows: Step 2.1, start the pump station motor: put the operating handles on the main engine in the non-working position. At this time, the indicated pressure of the pressure gauge on the pump station should not exceed 2Mpa, the oil temperature in the oil tank is above 200℃, and the liquid level is in the middle and upper part of the oil mark; Step 2.2, outrigger idle operation: slowly turn the outrigger control handle to the raised position, and the outrigger cylinders at all levels should extend smoothly; turn it to the lowered position, and the cylinders at all levels should retract smoothly; Step 2.3, motor idling: press the rotary motor control trigger, the drill rig spindle should have a controlled operation from slow to fast, and at the same time turn the outrigger control handle. The combined actions of the two should not interfere with each other and operate flexibly.

4. The rectangular jacking pipe rock formation pretreatment method according to claim 3 is characterized by: In step 3, The anchor construction is planned to use a track-type anchor drilling rig. In order to ensure that the depression angle and azimuth angle of the anchor hole axis during the construction process and after the hole is formed meet the design requirements, the accuracy and stability of the drilling rig must be ensured, and the axis of the hole-opening drill must be strictly checked to see if it is consistent with the axis of the designed anchor hole. The accuracy specifically includes: ① Adjust the elevation of the contact point between the vertical axis of the drilling rig and the slope surface to be consistent with the calibrated hole position; ② Adjust the axis of the vertical axis of the drilling hole to keep it consistent with the depression angle and azimuth angle of the designed center axis of the anchor hole; ③ The technical personnel shall measure and calibrate the axis of the drilling tool to make it consistent with the center axis of the anchor hole before drilling the hole; The stability specifically includes: ① Use clamping pipes to firmly secure the drilling rig; ② Test-run the drilling rig, calibrate the axis of the drilling tool and the center axis of the anchor hole again to make them consistent, and tighten the fastening screw; ③ The stability of the drilling rig must be ensured at all times during the drilling process; ④ During the construction process, set up a protector to ensure the drilling direction.

5. The rectangular jacking pipe rock formation pretreatment method according to claim 4, characterized in that: In step 4, Strictly measure and place points according to the required position and elevation, and mark them and indicate the drilling number; After the no-load test is normal, insert the hexagonal drill rod into the hexagonal hole of the drill rod joint, slowly press the motor control trigger to make the drill rod rotate slowly, turn the propulsion mechanism control handle to a smaller angle, slowly raise the legs to make the drill bit contact with the top plate, press the motor trigger, and the hole is completed after drilling about 20mm; The hole position deviation is ±10mm in the horizontal direction and ±5mm in the vertical direction. The allowable inclination angle of the drilling hole is less than 1%. The bottom edge and bottom R angle of the portal steel ring and the blind area are densely arranged in two rows, and the hole size is 100mm; pre-treat other parts, the hole size is 100mm, and the points are arranged in a plum blossom shape with a center spacing of 300mm*300mm; The designed slope of the jacking channel is 0.5%, the crushing slope of the drill pipe is 1%, and the crushing slope of the bottom two rows is controlled at 5% to increase the crushing surface; The slope is controlled by measuring with a level and each section of the anchor is reviewed to ensure the accuracy of the treatment range and to ensure that the rock within the jacking pipe range is fully crushed.

6. The rectangular jacking pipe rock formation pretreatment method according to claim 5, characterized in that: In step 5, The drilling method includes water drilling and pneumatic down-the-hole impact drilling. Water drilling uses water flow as the cutting medium and is suitable for drilling holes in hard rock or other difficult-to-drill materials. The pneumatic down-the-hole impact drilling uses compressed air as the power source, breaking the rock through the impact force of the impactor, and uses the follow-the-tube technology to maintain the stability and straightness of the borehole; At the same time, the drilling speed should be controlled at a uniform speed to ensure that the verticality and diameter of the drilling hole are consistent; The anchor hole is drilled using the pipe impact drilling process, and the casing can be pulled out only after the anchor rod is lowered into the drill hole.

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