Ground directional pipe drilling and cutting grouting construction process for deeply-buried long tunnel

Abstract

The invention discloses a deep-buried long tunnel ground directional drilling and cutting grouting construction process which comprises the following steps: S01, directional drilling construction and steel sleeve lowering: drilling holes step by step by adopting a directional drilling machine, and lowering a steel sleeve and fixing the steel sleeve after each stage of drilling hole reaches a preset depth; s02, hanger installation and sealing test: sealing the joint of the two sections of steel sleeves through the hanger, and performing sealing effect test; s03, lowering and slotting of a hydraulic cutting knife: connecting the hydraulic cutting knife through a drill rod, lowering the hydraulic cutting knife to a position to be grouted, and slotting the steel sleeve; s04, a stop-grouting plug is arranged, specifically, the stop-grouting plug is lowered to the position of the grouting section; and S05, grouting construction is conducted, specifically, grout is injected into the drill hole from the hole opening of the drill hole according to the designed grouting pressure and grouting amount, and grouting is conducted in sequence in a segmented mode through a retreating type grouting method. The technology improves the reliability of the pipe, achieves precise grouting, adapts to the ultrahigh pressure grouting environment, is efficient and controllable in grouting construction, and improves the comprehensive economy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of underground engineering, in particular to a deep-buried long tunnel ground directional drilling pipe cutting and grouting construction process. BACKGROUND

[0002] Deep-buried long tunnels generally refer to tunnels with a burial depth of more than 600 m and a length of more than 10 km. In the construction of deep-buried long tunnels, ground pre-grouting is a key measure to ensure construction safety and stability of surrounding rock. Among them, ground directional drilling bare hole reinforcement grouting is a commonly used grouting process, and a small amount of grouting engineering uses precast sleeve valve pipe for grouting. However, both of these two mainstream grouting process technologies have obvious drawbacks.

[0003] The defects of the precast sleeve valve pipe grouting process are mainly: (1) the contradiction between pipe reliability and economy is prominent. Using precast sleeve valve pipe for ground pre-grouting: when the precast sleeve valve pipe is lowered, the key component "valve skin" at the connection continuously rubs against the hole wall, which is easily damaged. Not only does it greatly increase the difficulty of lowering the pipe and the risk of pipe jamming, but it also seriously damages the sealing performance and directional grouting function, directly affecting the reinforcement effect. In order to avoid damage to the valve skin, the construction party often needs to prepare spare pipe materials or frequently pull out for inspection, which greatly increases the material cost, uncertainty of construction period and efficiency loss. In addition, the material and precision machining cost of the precast sleeve valve pipe is much higher than that of the ordinary steel sleeve pipe. In the face of large-scale grouting demand in a wide range of poor geological sections (such as fracture zones and water-rich layers), the cost of pipe materials is high, and its installation process is complex and delicate, which significantly increases the overall cost; (2) the mechanical property bottleneck of the valve skin material. In the precast sleeve valve pipe grouting process, the material defects of the valve skin at the connection become a key factor restricting its application in the superhigh pressure environment. The valve skin, as the core component for controlling sectional grouting, has limited reverse pressure resistance. When the grouting pressure exceeds 15 MPa, it is easy to be reversely pierced during grouting, causing pipe jamming. Once pipe jamming occurs, not only will the grouting process be immediately interrupted, which will seriously affect the grouting quality and reinforcement effect of the section, but also the subsequent pipe removal process will require a large amount of time, manpower and equipment resources, significantly increasing the uncertainty of project progress delay, cost overrun and safety risk. If the valve skin material is improved to enhance its pressure resistance in the superhigh pressure environment, the research cost will be high, which will significantly increase the project cost, making the precast sleeve valve pipe grouting process significantly less economical in superhigh pressure engineering applications.

[0004] The disadvantages of the bare hole reinforcement grouting process mainly include: (1) the grouting process lacks flexibility and pertinence, and the bare hole grouting operation can only passively perform "non-discriminatory" grouting on all opening sections. It is impossible to dynamically and selectively perform key and intensive grouting on the key soft and weak layers, fracture zones, water-rich areas or high-permeability strata of the tunnel according to fine geological survey, real-time core identification of the drilling or in-hole geophysical prospecting feedback. The consequences are that the slurry is wasted in the sections with good surrounding rock conditions, and the reinforcement effect is not ideal in the target poor strata sections that really need full reinforcement due to the limitation of the opening position, leaving safety hazards and being difficult to meet the fine and differentiated reinforcement needs of complex strata; (2) the grouting effect of the poor geological body is poor, the bare hole reinforcement grouting adopts hole mouth blocking grouting, the grouting is long section grouting, the grouting mechanism is complex, the grouting pressure of the hole bottom section gradually decays, the stone strength of the grouted section is low, and there is a possibility of repeated breakthrough, which is contrary to the basic principle that the small section grouting is suitable for the poor geological body, and the grouting effect of part of the tunnel section is poor.

[0005] In summary, the ground pre-grouting process relying on the bare hole grouting or the sleeve valve pipe in the deep-buried long tunnel engineering has defects in the pipe material reliability, grouting accuracy, super-high pressure grouting adaptability, construction controllability and comprehensive economy. SUMMARY

[0006] The purpose of the present application is to overcome the above technical deficiencies, and provide a deep-buried long tunnel ground directional drilling pipe cutting grouting construction process, which improves the pipe material reliability, realizes accurate grouting, adapts to the super-high pressure grouting environment, is efficient and controllable in grouting construction, and improves the comprehensive economy through five steps of directional drilling construction, sleeve pipe lowering, hanger installation and sealing test, hydraulic cutter lowering and slotting, grout stopper arrangement and grouting construction.

[0007] To achieve the above purpose, the deep-buried long tunnel ground directional drilling pipe cutting grouting construction process provided by the present application adopts the following technical solution: The deep-buried long tunnel ground directional drilling pipe cutting grouting construction process comprises the following steps: S01, directional drilling construction and steel sleeve pipe lowering, directional drilling is performed by using a directional drilling machine, after each drilling hole reaches the preset depth, the steel sleeve pipe is lowered and the pipe is fixed; S02, hanger installation and sealing test, the two steel sleeve pipes are connected through the hanger and the sealing effect is tested; S03, lowering and slotting of the hydraulic cutter: according to the results of the directional drilling exploration of the geological conditions, the position needing grouting is determined; the hydraulic cutter is connected through the drill rod and lowered to the position needing grouting to slot the steel sleeve pipe, and the slotting is used for accurate grouting; S04, grout stopper arrangement: the grout stopper is lowered to the top end position of the grouting section; S05, grouting construction: according to the design grouting pressure and grouting quantity from the borehole orifice into the borehole injection slurry, slurry through the slot penetration into the surrounding formation, using the retreating type grouting method section in turn, until the completion of all grouting segment construction.

[0008] Optionally, in step S01, three-stage drilling is performed using a directional drilling machine, the first-stage drilling includes: a first-stage borehole and casing lowering, a vertical section first-stage borehole is constructed using a directional drilling machine, after reaching the preset depth, a first-stage steel casing, i.e., a first-stage steel casing, is lowered, and pipe fixing is performed; the second-stage drilling includes: a second-stage borehole and casing lowering, a build-up section second-stage borehole is constructed using a directional drilling machine, after extending to the target stratum depth, a second-stage steel casing, i.e., a second-stage steel casing, is lowered, and pipe fixing is performed; the third-stage drilling includes: a third-stage borehole and casing lowering, a grouting section third-stage borehole is constructed using a directional drilling machine, after extending to the final hole depth, a third-stage steel casing, i.e., a third-stage steel casing, is lowered, and pipe fixing is performed.

[0009] Further, in step S01, the length of the second-stage steel casing is greater than the length of the first-stage steel casing, the upper half of the second-stage steel casing is nested inside the first-stage steel casing and coincides with the first-stage steel casing, the top orifice of the second-stage steel casing is flush with the top orifice of the first-stage steel casing and is located at the ground borehole; the lower half of the second-stage steel casing is a build-up section, one end of the lower part of the second-stage steel casing is connected to one end of the third-stage steel casing; in step S02, the connection between the second-stage steel casing and the third-stage steel casing is sealed by the hanger and a sealing effect test is performed.

[0010] Optionally, in step S02, a water pressure test is used to verify the sealing performance of the connection between the two steel casings.

[0011] Optionally, in step S03, the water jet cutter is a water jet inner cutter.

[0012] Optionally, in step S03, a stabilizer is further provided at the connection between the water jet cutter and the drill rod, and the size of the stabilizer is 3-6 mm smaller than the inner diameter of the steel casing.

[0013] Optionally, in step S03, the slot length of the slot is 1 / 3-2 / 3 of the circumference of the casing, the slot width is 0.5-1 cm, and the distance between each slot is 0.5-2 m.

[0014] Optionally, in step S05, the changes in grouting pressure and grouting quantity are monitored in real time during the grouting construction, and the grouting parameters are adjusted in a timely manner according to the monitoring results.

[0015] Further, in step S05, the slurry is modified single-liquid cement slurry, and the grouting pressure is 2-4 times the hydrostatic pressure.

[0016] Optionally, in the step S05, the backfill grouting method is adopted for segmented and sequential grouting, and the segmented length is 30-60 m.

[0017] The present application has the following advantages: 1. The present application adopts the ground directional drilling pipe cutting grouting construction process, which avoids the wear and tear risk of the valve skin in the hole wall friction during the lowering process of the prefabricated steel flower pipe in the prior art, greatly reduces the material loss, and thus improves the pipe reliability. 2. The ground directional drilling pipe cutting grouting construction process can flexibly adjust the grouting position according to the real-time geological survey data, core information and borehole geophysical prospecting results obtained during the drilling process, realize targeted grouting of high-risk areas such as key soft layers, fracture zones or water-rich areas of the tunnel, and meet the differentiated and refined grouting requirements of complex strata, thus improving the accuracy of grouting operation. 3. The ground directional drilling pipe cutting grouting construction process does not need to rely on valve skin control for segmented grouting, completely avoids the defect of insufficient reverse pressure bearing capacity of the valve skin under superhigh pressure environment, and can stably and continuously carry out grouting operation under superhigh pressure working condition, thus improving the adaptability to superhigh pressure grouting environment. 4. Compared with the forward grouting adopted by the current mainstream grouting process, the backfill grouting method adopted by the present application has obvious advantages. After cutting the pipe, the grouting method carries out segmented grouting from the hole, can accurately control the grouting pressure and slurry volume of each segment, uniformly fills the stratum pore, and does not need to repeat the hole scanning; the cutting seam position (grouting position) can be flexibly adjusted according to the situation, so the grouting construction is efficient and controllable. 5. The present application adopts the "on-demand pipe cutting" concept and optimized backfill segmented grouting method, which on the one hand significantly reduces the pre-fabrication cost of the sleeve valve pipe and the "valve skin" wear cost in the prior art; on the other hand, the on-demand cutting of the cutting seam accurately controls the grouting range and flow, avoids waste of grouting in the stable surrounding rock area, and saves the cost of grouting; thirdly, the process simplifies the installation process, shortens the construction period, reduces the labor and equipment investment, and thus improves the overall economic efficiency of the construction. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 The present application is a construction process flowchart; Fig. 2 The present application is a ground directional drilling pipe cutting grouting construction site layout schematic diagram; Fig. 3 The present application is a ground directional drilling pipe cutting grouting construction site layout schematic diagram; Among them: 1. Directional drilling rig; 2. First-stage drilling; 3. Second-stage drilling; 4. Third-stage drilling; 5. Adverse geological sections; 6. Deeply buried long tunnels; 7. Steel casing; 8. Slot cutting; 9. Hydraulic cutter; 10. Drill rod; 11. Hanger. Detailed Implementation

[0019] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The following is in conjunction with the appendix Figs. 1-3 The present invention will be described in further detail below.

[0021] like Figs. 1-3 As shown, the surface directional drilling and grouting construction process for deep-buried long tunnels includes the following steps: S01. Directional drilling construction and steel casing 7 lowering: directional drilling rig 1 is used to drill holes in stages. After each stage of drilling reaches the preset depth, the steel casing 7 is lowered and fixed. S02, Installation and sealing test of hanger 11: The two sections of steel sleeve 7 are connected by hanger 11 and the sealing effect is tested. S03, Lowering and Slotting of Hydraulic Cutter 9: Based on the geological conditions of the directional drilling exploration, the location where grouting is required is determined; the hydraulic cutter 9 is connected to the drill rod 10 and lowered to the location where grouting is required, and slots are made in the steel casing 7. The slots 8 are used for precise grouting. S04, Grout stop plug arrangement: Lower the grout stop plug to the top of the grouting section; S05. Grouting construction: According to the designed grouting pressure and grouting volume, grout is injected into the borehole from the borehole opening. The grout penetrates into the surrounding strata through the cut 8. The grouting is carried out in sections by section using the retreating grouting method until all grouting sections are completed.

[0022] In some embodiments, in step S01, the directional drilling machine 1 is used to drill a three-stage hole, the first stage hole includes: a first drilling hole 2 and casing lowering, the directional drilling machine 1 is used to construct a vertical section first drilling hole 2, after reaching the preset depth, a first stage steel casing 7, i.e., a first drilling steel casing, is lowered, and the pipe is fixed; the second stage hole includes: a second drilling hole 3 and casing lowering: the directional drilling machine 1 is used to construct a build-up section second drilling hole 3, after extending to the target stratum depth, a second stage steel casing 7, i.e., a second drilling steel casing, is lowered, and the pipe is fixed; the third stage hole includes: a third drilling hole 4 and casing lowering: the directional drilling machine 1 is used to construct a grouting section third drilling hole 4, after extending to the final hole depth, a third stage steel casing 7, i.e., a third drilling steel casing, is lowered, and the pipe is fixed. By using this technical solution, the drilling accuracy can be improved and dynamic deviation correction is facilitated. Compared with the problem that the traditional drilling machine is easy to deviate from the preset path in long distance construction, this scheme realizes accurate transition from vertical to target stratum through staged build-up (such as a second build-up section), ensuring that the final hole depth and the target position are highly consistent.

[0023] In some embodiments, in step S01, the length of the second drilling steel casing is greater than the length of the first drilling steel casing, the upper half of the second drilling steel casing is nested inside the first drilling steel casing and coincides with the first drilling steel casing, the top pipe opening of the second drilling steel casing is flush with the top pipe opening of the first drilling steel casing, and both are located at the ground drilling hole; the lower half of the second drilling steel casing is a build-up section, and one end of the lower part of the second drilling steel casing is connected to one end of the third drilling steel casing; in step S02, the connection between the second drilling steel casing and the third drilling steel casing is sealed by a hanger 11 and a sealing effect test is performed. By using this technical solution, the upper half of the second drilling steel casing is located inside the first drilling steel casing and coincides with the first drilling steel casing, further improving the stability of the second drilling steel casing.

[0024] In some embodiments, in step S02, a water pressure test is used to verify the sealing performance of the connection between the two steel casings 7. By using this technical solution, a test pressure higher than the working pressure (more than 1.25 times the working pressure) is applied, and a stable pressure state (30 minutes) is maintained. The water pressure test can force the exposure of hidden defects such as micro-cracks, pores or thread gap of the connection between the steel casings 7, and the leakage characteristics of the liquid medium under high pressure are obvious, which facilitates the timely discovery of leakage points through visual or instrument detection.

[0025] In some embodiments, in step S03, the hydraulic cutter 9 is a hydraulic internal cutter. By using this technical solution, after the pump is stopped, the pressure difference disappears, the spring pushes the lower slide valve back to its original position and retracts the blade, avoiding the risk of tripping caused by the blade being stuck in the traditional tool.

[0026] In some embodiments, in step S03, a stabilizer, the water jetting cutter 9, a stabilizer, a conversion joint, the drill pipe 10, a rotary head, and a kelly bar are sequentially arranged at the connection between the water jetting cutter 9 and the drill pipe 10, and the stabilizer has a size that is 3-6 mm smaller than the inner diameter of the steel casing 7. By adopting the technical scheme, the stabilizer ensures the accuracy and safety of the cutting operation of the steel casing 7 through multiple action mechanisms.

[0027] In some embodiments, in step S03, the slit length of the slit 8 is 1 / 3-2 / 3 of the circumference of the casing, the slit width is 0.5-1 cm, and the spacing between each slit 8 is 0.5-2 m. By adopting the technical scheme, the slurry penetrates into the surrounding formation through the slit 8 and is more evenly distributed, thereby improving the reinforcement effect.

[0028] In some embodiments, in step S05, the grouting pressure and the grouting amount are monitored in real time during the grouting construction, and the grouting parameters are adjusted in a timely manner according to the monitoring results. By adopting the technical scheme, the grouting accuracy can be further improved.

[0029] In some embodiments, in step S05, the slurry is modified single-liquid cement slurry, and the grouting pressure is 2-4 times the hydrostatic pressure. By adopting the technical scheme, the material performance is optimized and the pressure is synergistically controlled, and the core problem of poor diffusivity in traditional grouting technology is systematically solved.

[0030] In some embodiments, in step S05, a retreating grouting method is adopted for segmented and sequential grouting, and the segmented length is 30-60 m. By adopting the technical scheme, the segmented grouting can accurately control the pressure and the slurry amount, and does not need to repeatedly scan the hole, thereby significantly improving the grouting efficiency.

[0031] Embodiment one The following takes a deep buried long tunnel 6 of a large-scale water diversion project as an example to illustrate the specific implementation steps of the application: Step S01: directional drilling construction and steel casing 7 lowering; According to the actual terrain and existing road construction conditions, the ground pre-grouting drill field is arranged, and the ground directional drilling construction is carried out. The grouting drilling is divided into three levels: the first drilling hole 2 is a vertical section, the opening diameter is 311 mm, a first opening steel casing is lowered, the first opening steel casing is a Φ245*9 mm oil casing; the second drilling hole 3 is a build-up section, the diameter is 216 mm, a second opening steel casing is lowered, the second opening steel casing is a Φ178*8 mm oil casing; the third drilling hole 4 is a horizontal grouting section, the opening diameter is 152 mm, a third opening steel casing is lowered, the third opening steel casing is a Φ133*6 mm oil casing. The length of the second opening steel casing is greater than the length of the first opening steel casing, the upper half of the second opening steel casing is nested inside the first opening steel casing, and the top of the second opening steel casing is flush with the top of the first opening steel casing, and they are both located at the ground drilling hole; the lower half of the second opening steel casing is a build-up section, and the lower end of the second opening steel casing is connected with one end of the third opening steel casing, and after each level of casing is lowered, casing fixation construction is carried out. In this embodiment, the steel pipe cutting grouting method is used on site, which is based on the steel pipe compression resistance principle in material mechanics, the steel pipe is made of high-strength steel material and can withstand a pressure of more than 40 MPa, so the grouting pressure can reach more than 40 MPa. During grouting, the steel pipe is cut through a specific process and arranged reasonably, so that the pressure loss can be controlled in a very small range, the grouting pressure can be stabilized at more than 40 MPa, and the adaptability breakthrough of super-high pressure is realized.

[0032] Step S02: hanger 11 installation and sealing test; The second opening steel casing and the third opening steel casing are connected through the hanger 11, and a water pressure test is used on site to verify the sealing performance of the casing joint (i.e. the hanger 11) to ensure good sealing effect.

[0033] Step S03: lowering and cutting of the hydraulic cutter 9; According to the ground grouting treatment hole section initially determined by the geophysical prospecting result, the range of the hole section is pile number DL I 27+832~28+475, and the length is 643 m. In the implementation process, according to the geological exploration result of the ground directional drilling, the ground pre-grouting treatment hole section is finely divided. Then, the hydraulic cutter 9 is lowered through the drill rod 10, and the sectional cutting is carried out according to the geological exploration result of the ground directional drilling.

[0034] The SFGD type water-based composite internal cutter is used for cutting the steel pipe on site. The working principle of the hydraulic cutter 9 is that after it is lowered to the predetermined cutting position, the rotating drill string is opened, the pump is circulated, the discharge and pump pressure are gradually increased, the piston rod is lowered under the action of the pump pressure, the lower end face of the piston rod abuts against the upper end face of the cutter blade, and when the piston rod continues to move downward, the cutter blade is slowly opened to cut the casing. When the casing is cut, the torque of the drill string decreases. After the pump is stopped, the piston rod is moved upward to reset under the action of the spring, and the cutter blade is retracted into the body under the action of its own weight.

[0035] The hydraulic cutter 9 selects different tool outer diameters and cutter head lengths according to the casing, and selects nozzles with different inner diameters according to pump pressure requirements and actual discharge. The on-site cutter selection model is ND-S178, the tool outer diameter is 140 mm, and the joint connection thread is NC38. The drilling assembly adopts: stabilizer + hydraulic composite cutting tool + stabilizer + conversion joint + drill pipe 10 + swivel head + kelly. The stabilizer is 3-6 mm smaller than the inner diameter of the casing. In this embodiment, the stabilizer inner diameter is 174 mm.

[0036] The basic working principle of the pipe cutting is as follows: the hydraulic inner cutter is a tool that uses the liquid force of circulating drilling fluid to push the cutter to cut the pipe. It can cut at any position except the coupling. When the tool is lowered to the desired cutting position, the pump is started to circulate and the discharge is gradually increased. Due to the cutting flow of the nozzle, a relatively high pressure chamber is formed in the upper part of the piston, which pushes the piston down. The lower end of the piston also pushes out the cutting blade, and the cutter head points to the inner wall of the casing. Under the condition of maintaining appropriate pump pressure and discharge, the rotary table is started, and the cutter is driven by the drill string to cut. When the cutting is completed, the pump is stopped, the differential pressure is eliminated, and the reset spring makes the piston reset upward, and the cutter head is reset.

[0037] The specific operation process is as follows: (1) Lower the cutter: according to the required casing specification, select the corresponding inner cutter and appropriate drill pipe 10, connect the cutter to the lower end of the drill pipe 10, and lower it to the desired cutting position; (2) Start the pump to circulate and gradually increase the discharge. Select appropriate pump pressure and discharge to enable the cutter head to continuously feed. Start the rotary table at a speed of 30-50 rpm, and cut in the forward direction; (3) After cutting for 5-10 minutes, the driller observes the change in torque. When the torque decreases or the rotary table chain jumps, and the sensitive needle flashes, it indicates that the casing is cut off; (4) Stop the pump to reset the cutter head, and then pull out the drill pipe.

[0038] The length of the cutting slot 8 is 1 / 3-2 / 3 of the circumference of the casing, the width of the cutting slot 8 is 0.5-1 cm, and the distance between the cutting slots 8 is 0.5-2 m.

[0039] The on-site hydraulic cutter 9 pipe cutting test is carried out, and the obtained parameters are shown in Table 1: Table 1: On-site hydraulic cutter pipe cutting test parameters Step S04: Stop the grout plug and lower it to the top of the grouting section; Step S05: Grouting construction; The backfill grouting method is used on site, and grouting is performed from the orifice after each cutting section is completed. According to the geological conditions on site, modified single-liquid cement slurry is selected, and the grouting pressure is 2 to 4 times the hydrostatic pressure. The backfill grouting method is used for sectional grouting in sequence, and the sectional length is 30 to 60 m. According to the geological conditions on site, the sectional length of the grouting construction in this embodiment is 30 m, and the grouting is performed in sequence and backfill until the construction of all grouting sections is completed.

[0040] The technical core of the deep-buried long tunnel ground directional drilling pipe cutting and grouting construction process is to innovate and integrate the "drilling-cutting-injection" integrated technology system. Through the "on-demand pipe cutting" concept, the limitations of the existing prefabricated pipe grouting process are solved, and the complex stratum is finely reinforced. Specifically, (1) on-site pipe cutting replaces prefabricated pipes: by cutting the grouting hole on site after directional drilling, i.e., cutting the joint 8, the risk of wear and tear caused by lowering prefabricated pipes (such as sleeve valve pipes) is completely avoided, the cost of materials and processing is significantly reduced, and the installation process is simplified, while ensuring the sealing and directional functions, the economy and reliability are improved; (2) on-demand hole cutting precise grouting: based on real-time geological data (core, geophysical prospecting) of drilling, the grouting position is flexibly adjusted, and targeted reinforcement is implemented for high-risk areas such as soft layers and fracture zones; by precisely controlling the position of the cutting joint 8 and the slurry flow, invalid diffusion is avoided, and differential and fine grouting of complex strata is achieved, forming a closed-loop control of "geological adaptation-precise cutting-differential grouting"; (3) ultra-high pressure adaptability breakthrough: abandoning the traditional way of relying on valve skin control for sectional grouting, the defect of insufficient reverse pressure bearing of valve skin in an ultra-high pressure environment is avoided, and the grouting pressure can reach more than 40 MPa, significantly improving the grouting effect of deep-buried long tunnel sections with poor geology, greatly improving the safety and controllability of construction, achieving continuous and stable grouting, improving the reliability and economy of construction under complex geological conditions, and reducing emergency handling costs; (4) through process innovation, the grouting construction efficiency is greatly improved, through the innovative backfill grouting method, the pressure and slurry amount are precisely controlled, and there is no need to repeat the hole scanning, which significantly improves the controllability and grouting efficiency of construction; (5) the synergistic effect of various innovative technologies effectively solves the limitations of the existing prefabricated pipe grouting process, reduces cost investment, shortens the construction period, improves the construction efficiency, and improves the overall economy.

[0041] It should be noted that the above technical solutions are exemplary, and the present specification can be embodied in different forms, and should not be interpreted as being limited to the technical solutions set forth herein. On the contrary, providing these descriptions will make the present disclosure thorough and complete, and will fully convey the scope disclosed by the present specification to those skilled in the art. In addition, the technical solutions of the present application are limited by the scope of the claims.

Claims

1. A surface directional drilling and grouting construction process for deep-buried long tunnels, characterized in that... Comprising the following steps: S01, directional drilling construction and steel casing (7) down, using directional drilling machine (1) to drill hole, each level drilling hole reaches the preset depth, the steel casing (7) is lowered and the pipe is fixed; S02, hanger (11) installation and sealing test, the two sections of the steel casing (7) are connected through the hanger (11) and the sealing effect test is carried out; S03, the down of the water jetting cutter (9) and the cutting slot: according to the result of the directional drilling exploration, the position needing grouting is determined; the water jetting cutter (9) is connected through the drill rod (10) and is lowered to the position needing grouting, the steel casing (7) is cut, and the cutting slot (8) is used for accurate grouting; S04, grout stopper arrangement: the grout stopper is lowered to the top position of the grouting section; S05, grouting construction: according to the designed grouting pressure and grouting amount, the slurry is injected into the drilling hole from the drilling hole opening, the slurry penetrates into the surrounding stratum through the cutting slot (8), and the back-off grouting method is used to grout section by section until all the grouting sections are constructed.

2. The deep-buried long tunnel ground directional drilling pipe cutting grouting construction process according to claim 1, characterized in that: in the step S01, the directional drilling machine (1) is used to carry out three-stage drilling, the first-stage drilling includes: a drilling hole (2) and casing lowering, the directional drilling machine (1) is used to construct a vertical section a drilling hole (2), after reaching the preset depth, the first-stage steel casing (7), namely a steel casing, is lowered and the pipe is fixed; the second-stage drilling includes: a two-stage drilling hole (3) and casing lowering: the directional drilling machine (1) is used to construct a build-up section two-stage drilling hole (3), after extending to the target stratum depth, the second-stage steel casing (7), namely a two-stage steel casing, is lowered and the pipe is fixed; the third-stage drilling includes: a three-stage drilling hole (4) and casing lowering: the directional drilling machine (1) is used to construct a grouting section three-stage drilling hole (4), after extending to the final hole depth, the third-stage steel casing (7), namely a three-stage steel casing, is lowered and the pipe is fixed.

3. The deep-buried long tunnel ground directional drilling pipe cutting grouting construction process according to claim 2, characterized in that: in the step S01, the length of the two-stage steel casing is greater than the length of the one-stage steel casing, the upper half of the two-stage steel casing is nested inside the one-stage steel casing and coincides with the one-stage steel casing, the top pipe opening of the two-stage steel casing is flush with the top pipe opening of the one-stage steel casing and is located at the ground drilling hole; the lower half of the two-stage steel casing is a build-up section, one end of the lower part of the two-stage steel casing is connected with one end of the three-stage steel casing; in the step S02, the connection of the two-stage steel casing and the three-stage steel casing is sealed through the hanger (11) and the sealing effect test is carried out.

4. The deep-buried long tunnel ground directional drilling pipe cutting grouting construction process according to claim 1, characterized in that: in the step S02, the sealing performance of the connection of the two sections of the steel casing (7) is verified by water pressure test.

5. The deep-buried long tunnel ground directional drilling pipe cutting grouting construction process according to claim 1, characterized in that: The step S03, the water force cutter (9) is water force type inner cutter.

6. The ground directional drilling pipe cutting and grouting construction process for deep and long tunnel according to claim 1, characterized in that: The step S03, the water force cutter (9) and the drill rod (10) connection place is also provided with a stabilizer, the stabilizer size is 3-6mm smaller than the inner diameter of the steel casing (7).

7. The ground directional drilling pipe cutting and grouting construction process for deep and long tunnel according to claim 1, characterized in that: The step S03, the slit length of the cutting slit (8) is 1 / 3-2 / 3 of the casing circumference, the slit width is 0.5-1cm, and the interval of each cutting slit (8) is 0.5-2m.

8. The ground directional drilling pipe cutting and grouting construction process for deep and long tunnel according to claim 1, characterized in that: The step S05, the grouting pressure and the grouting amount change are monitored in real time during the grouting construction process, and the grouting parameters are adjusted in time according to the monitoring results.

9. The ground directional drilling pipe cutting and grouting construction process for deep and long tunnel according to claim 8, characterized in that: The step S05, the slurry is modified single-liquid cement slurry, and the grouting pressure is 2-4 times of the hydrostatic pressure.

10. The ground directional drilling pipe cutting and grouting construction process for deep and long tunnel according to any one of claims 1-9, characterized in that: The step S05, the retreating grouting method is adopted to segmentally and sequentially grout, and the segment length is 30-60m.

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