Surface ultra-deep hole directional controlled grouting construction method

Abstract

The application discloses a kind of ground ultra-deep hole directional control area grouting construction methods, comprising: according to the size requirement of setting production targeting grouting valve pipe;Level construction site, measurement, calibration, and drill the position of several grouting holes;With PE pipe together hoist into one of grouting holes targeting grouting valve pipe, through the pressure pipe and pressure pump connection of inner mixed grouting plug, and through lifting steel rope and winch system connection, inner mixed grouting plug and grouting core pipe are placed into targeting grouting valve pipe, and descend to the depth of pre-grouting;Shell material is injected into grouting hole through PE pipe;Grouting core pipe is connected good grouting pipeline, and inner mixed grouting plug is implemented retreating type sectional grouting;And after a grouting is completed, pull out inner mixed grouting plug to next grouting paragraph, repeat the above steps, until the completion of grouting hole all grouting paragraph.

Description

Technical Field

[0001] This invention belongs to the field of advanced surface reinforcement, and particularly relates to a grouting pre-reinforcement construction method for medium-deep buried tunnels with adverse geological conditions. Background Technology

[0002] In tunnel engineering, the surface grouting technology is often used, and the grouting depth is mostly within 60 meters. For the pre-reinforcement measures of medium-deep buried complex geological tunnels, the bench method, the central diaphragm tunnel method, or the CRD method are often used for excavation. However, the above methods have complex construction procedures and cannot avoid the problems of face collapse and structural deformation. The construction risks are extremely high, the progress is slow, and the construction costs are high.

[0003] To ensure construction safety and structural stability, the current pre-reinforcement measures for medium-deep buried tunnels with adverse geological conditions mostly adopt the in-tunnel curtain grouting process. However, in-tunnel curtain grouting construction requires grouting one section, excavating one section, and reserving another section. The tunnel face is operated as a single process, with 20-30 meters of reinforcement and 15-25 meters of excavation in a cycle. Grouting reinforcement and tunnel excavation construction cannot be carried out simultaneously. The monthly tunnel progress is only 15-20 meters, which takes a long time and has high hidden costs.

[0004] For example, Chinese Patent Application No. 201611180026.4 discloses a grouting structure and grouting method for ultra-deep hole dual-liquid grouting on the surface. The key technical points of the solution include a borehole opened on the surface, a sleeve valve pipe placed in the borehole, a plug installed in the sleeve valve pipe, and a sealed mixing chamber formed between the plug and the bottom of the sleeve valve pipe. A first grouting pipe and a second grouting pipe connected to the mixing chamber are provided in the borehole. Grouting holes are provided on the inner wall of the mixing chamber. A sleeve is fitted with a rubber sleeve to block the grouting hole at the corresponding position of the sleeve valve pipe. The plug is used to seal and form a sealed mixing chamber, so that cement grout and water glass grout can be injected into the mixing chamber through the first grouting pipe and the second grouting pipe respectively for mixing. However, this grouting method for ultra-deep hole dual-liquid grouting on the surface has the following disadvantages or deficiencies: (1) The grouting pipe structure is complex, the grouting is difficult, and the grouting process takes a long time; (2) Grouting reinforcement and tunnel excavation construction cannot be carried out at the same time.

[0005] Therefore, providing a surface ultra-deep hole directional controlled grouting construction method suitable for advanced pre-reinforcement of medium-deep buried tunnels with adverse geological conditions, and meeting the requirements of safe tunnel construction, control of structural deformation, and significant improvement of tunnel construction progress has become an urgent problem to be solved in the industry. Summary of the Invention

[0006] The purpose of this invention is to provide a surface ultra-deep hole directional controlled grouting construction method (DDK technology). By changing the grouting equipment, grouting materials, grouting methods, and grouting processes, it enables precise and targeted pre-reinforcement of adverse geological conditions ahead of the tunnel face under deep-buried conditions in tunnels. This achieves safe tunnel construction, controls structural deformation, and improves tunnel construction progress, providing a new option for grouting reinforcement of soft strata in deep tunnels in the industry.

[0007] To achieve the above objectives, the present invention provides a method for directional controlled grouting construction of ultra-deep boreholes on the surface, comprising: (1) fabricating a targeted grouting valve pipe according to the set size requirements; (2) leveling the construction site, measuring and marking the positions of several grouting holes, and drilling sequentially to the set hole depth at the marked positions to complete the drilling of all grouting holes; (3) hoisting the targeted grouting valve pipe and PE pipe together into one of the grouting holes, injecting casing material into the grouting hole through the PE pipe to seal the gap between the targeted grouting valve pipe and the hole wall of the grouting hole; (4) connecting the internal mixing grouting plug to a pressure pump through a pressure pipe and connecting it to a hoisting system through a lifting steel rope, connecting the grouting core pipe to the internal mixing grouting plug and placing it into the targeted grouting valve pipe, and lowering it to the pre-grouting depth, using the pressure pump to inflate the internal mixing grouting plug through the pressure pipe, connecting the grouting core pipe to the grouting pipeline, and implementing backward segmented grouting through the internal mixing grouting plug; and (5) After a section of grouting is completed, pull out the internal mixing grouting plug to the next grouting section, and repeat step (4) until all grouting sections of the grouting hole are completed.

[0008] The surface ultra-deep hole directional controlled grouting construction method of the present invention can meet the target grouting construction in the range of hole depth from 60 to 300 meters.

[0009] Optionally, in step (1), the wall of the targeted grouting valve pipe is provided with several rows of overflow holes, and a stop valve sleeve and a stop valve sleeve protector are fitted on each row of overflow holes; the targeted grouting valve pipe includes a first type targeted grouting valve pipe and several second type targeted grouting valve pipes. The diameter and wall thickness of the first type targeted grouting valve pipe and the second type targeted grouting valve pipe are the same. One end of the first type targeted grouting valve pipe is provided with a guide tip, and the other end is provided with an external / internal thread. The two ends of the second type targeted grouting valve pipe are respectively provided with an internal thread and an external thread.

[0010] Optionally, an outer sleeve joint is welded at the connection of the two Type II targeted grouting valve pipes. That is, the connection of the two Type II targeted grouting valve pipes is made by full welding or threaded connection of the outer sleeve joint. The length of the outer sleeve joint is not less than 60 cm, and the inner diameter of the outer sleeve joint is not greater than the outer diameter of the targeted valve pipe by 3 mm.

[0011] Alternatively, in step (1), the targeted grouting valve pipe is manufactured using seamless steel pipes with diameters of 60 mm, 76 mm, or 89 mm. The wall thickness of the targeted grouting valve pipe can be set to 2–10 mm, for example, 3–8 mm.

[0012] Alternatively, in step (2), the drilling method is set to high-pressure air drilling, water drilling, or mud wall drilling.

[0013] Preferably, in step (2), the drilling rig used has good stability and the drilling angle meets the design requirements.

[0014] Alternatively, in step (3), the casing material is composed of the following parts by weight of raw materials: 100 parts water, 100-200 parts cement, and 100-300 parts bentonite.

[0015] Optionally, in step (4), if a single-liquid grout is used during grouting, one grouting core tube is set; if a double-liquid grout is used during grouting, two grouting core tubes are set. The diameter of the grouting core tube is set to 15 mm or 20 mm.

[0016] Alternatively, when grouting, a two-component grout is used, with the grouting core tube connected to the two-component grouting pump via a high-pressure grouting hose.

[0017] Alternatively, in step (4), the grouting liquid is sulfoaluminate cement single-liquid grout, modified ordinary cement single-liquid grout, or cement-water glass two-liquid grout.

[0018] Preferably, in step (4), the grout has the characteristics of rapid setting and early strength. The initial setting time of single-liquid grout is 25-45 min, the final setting time is 30-60 min, and the initial setting time of double-liquid grout is 30-300 s.

[0019] Optionally, in step (4), the segment length of the grouting section is set to 0.75 to 2 meters, and the grouting pressure is set to 1 to 30 MPa.

[0020] Alternatively, in step (5), the pressure pump is depressurized, the internal mixing grout plug contracts, and then the hoisting system is used to lift the internal mixing grout plug to the next grouting section via a lifting steel rope.

[0021] This invention also provides a method for directional controlled grouting construction of ultra-deep boreholes on the surface, the construction steps of which are as follows: (1) Drill overflow holes at the design positions of seamless steel pipes of corresponding specifications, install grout stop valve sleeves, install grout stop valve sleeve protectors, process connectors, and process them into targeted grouting valve pipes. Among them, the first targeted grouting valve pipe in the grouting hole should be equipped with a guide tip when it is installed; (2) Level the construction site, accurately measure and lay out the hole positions, adjust the drilling rig to the design angle after it is in place, and drill the hole to the design depth; (3) Hoist the processed targeted grouting valve pipes together with PE pipes into the drilled holes, connect each targeted grouting valve pipe firmly until the corresponding design depth, install pipes with grout stop valve sleeves in the designed targeted grouting sections, and install bare pipes in the non-grouting sections; (4) Inject a certain strength of casing material through the PE pipe to seal the gap between the targeted grouting valve pipe and the borehole wall to prevent vertical crossflow of grout; (5) Connect the pressure pump to the internal mixing grouting plug with the pressure pump pipe, and lift the pump. (6) Connect the wire rope to the hoisting system; (7) Connect the grouting core pipe, the internal mixing grouting plug pressure pipe and the lifting wire rope; (8) After installing the double core pipe, the pressure pipe with the internal mixing grouting plug and the lifting wire rope in the targeted grouting valve pipe, install it to the pre-grouting depth; (9) After the casing material solidifies, connect the grouting pipeline and implement the backward segmented grouting through the internal mixing grouting plug; (10) According to different geological conditions, different types of grout can be injected in different sections. You can choose grout with fast setting, early strength and controllable gel time, and realize repeated grouting in the same section; (11) After the grouting of one section is completed, pull out the internal mixing grouting plug to the next grouting section until all grouting sections of this hole are completed.

[0022] The beneficial effects of this invention are: (1) It does not require waiting for problems to occur in the excavation and support of the unfavorable geological section before taking measures to deal with them, thus avoiding the construction safety risks and work stoppage risks caused by unfavorable geology; (2) The surface ultra-deep hole directional control grouting pre-reinforcement process does not overlap with the tunnel excavation and support construction process, and parallel operations can be achieved; (3) It enables large-scale construction and rapid passage through unfavorable geological sections, which can effectively shorten the construction period; (4) The reinforcement effect is guaranteed, which can ensure construction safety and structural safety. Attached Figure Description

[0023] Figure 1A and Figure 1B A schematic diagram of step (1) of the surface ultra-deep hole directional controlled grouting construction method of the present invention is shown.

[0024] Figure 2A and Figure 2B A schematic diagram of step (2) of the surface ultra-deep hole directional controlled grouting construction method of the present invention is shown.

[0025] Figure 3A and Figure 3B A schematic diagram of step (3) of the surface ultra-deep hole directional controlled grouting construction method of the present invention is shown.

[0026] Figure 4 A schematic diagram of step (4) of the surface ultra-deep hole directional controlled grouting construction method of the present invention is shown. Detailed Implementation

[0027] The following describes the surface ultra-deep hole directional controlled grouting construction method of the present invention in detail with reference to the accompanying drawings.

[0028] First, the targeted grouting valve pipe is fabricated in step 1. According to the designed cutting length of the steel pipe, overflow holes 2 are drilled on steel pipe 1A or 1B. Then, the grout stop valve sleeve 3 is installed, and the connecting kit, i.e., the outer sleeve joint (not shown in the figure), is processed. The targeted grouting valve pipe includes, as follows: Figure 1A The first type of targeted grouting valve pipe shown and such Figure 1B The second type of targeted grouting valve pipe shown has the same diameter and wall thickness as the first type of targeted grouting valve pipe. One end of the first type of targeted grouting valve pipe is provided with a guide tip, and the other end is provided with an external thread 4. The two ends of the second type of targeted grouting valve pipe are respectively provided with an external thread 4 and an internal thread 5.

[0029] In this non-limiting embodiment, the end of the first type of targeted grouting valve pipe is not limited by internal or external threads, and its thread type can be the same as that of the second type of targeted grouting valve pipe. Moreover, in this step, the processing order of thread processing, overflow hole drilling and grout stop valve sleeve can be selected by oneself, thereby improving the manufacturing efficiency of the targeted grouting valve pipe.

[0030] In this non-limiting embodiment, an outer sleeve joint is welded to the connection point of the two type II targeted grouting valve pipes. That is, the connection between the two type II targeted grouting valve pipes is achieved by full welding or threaded connection of the outer sleeve joint. The length of the outer sleeve joint is not less than 60 cm, and the inner diameter of the outer sleeve joint is not greater than the outer diameter of the targeted valve pipe by 3 mm. The targeted grouting valve pipes are manufactured using seamless steel pipes with diameters of 60 mm, 76 mm, or 89 mm.

[0031] Next, in step 2, as Figure 2A As shown, level the construction site, mark the boundaries of the reinforcement area, measure and mark the positions of the boreholes 6 of the designed targeted grouting valve pipe, and mark the center of the boreholes and crosshairs with paint, and mark the station numbers according to the design. Then, as... Figure 2BAs shown, a tracked drilling rig 7 located on the ground surface F is used. The hole position parameters are adjusted at the marked hole position, and the drill rod 8 is adjusted according to the design requirements. Drilling is carried out using a drill bit 9 with the corresponding diameter of the targeted grouting valve pipe. At the beginning of the drilling construction, the inclination should be measured as required to ensure that the drilling angle deviation meets the design requirements. Then, the drill rod 8 is extended to drill to the design depth. Subsequently, hole washing or cleaning is carried out to ensure that the installation depth of the targeted grouting valve pipe meets the design requirements. After the hole washing or cleaning is completed, the drill rod 8 is disassembled to complete the drilling of the grouting hole 10.

[0032] Then, in step 3, as Figure 3A As shown, firstly, using the drilling rig 7 and with the assistance of the power head 12, the targeted grouting valve pipe 1, along with the PE pipe 13, is hoisted into the hole using the sling 11, and connected to the bottom of the hole one by one. Then, as... Figure 3B As shown, casing material 14 is injected into the grouting hole 10 through PE pipe 13, thereby sealing the gap between the targeted grouting valve pipe 1 and the hole wall of the grouting hole 10. During the injection of casing material, a ball valve 15 is installed at the top end of PE pipe 13.

[0033] Next, in step 4, the internal mixing grouting plug 16 is connected to the pressure pump 18 via the pressure pipe 17, thereby using the pressure pump 18 to inflate the internal mixing grouting plug 16. Simultaneously, the internal mixing grouting plug 16 is connected to the hoisting system 20 via the lifting steel rope 19, thereby using the hoisting system 21 to lift the internal mixing grouting plug 16. In this non-limiting embodiment, two grouting core tubes 21 are connected to the internal mixing grouting plug 16 and placed inside the targeted grouting valve pipe 1. During the lowering process, the grouting core tubes 21 are lengthened section by section until they reach the bottom of the hole.

[0034] After the casing material 14 has solidified, the grouting core pipe 21 is connected in sequence to the high-pressure grouting hose 22, the dual-liquid grouting pump 23, the grout delivery pipe 24, the A-liquid mixing tank 25A and the B-liquid mixing tank 25B. The pressure pump 18 is used to expand the internal mixing grouting plug 16 through the pressure pipe 17 to complete the targeted grouting Z of this section. Then, the segmented grouting with a step-by-step backward movement begins.

[0035] In this non-limiting embodiment, in this step, appropriate grouts need to be injected into different geological sections according to different geological conditions, or different grouts can be injected into the same section.

[0036] Finally, in step 5, after a section of grouting is completed, the pressure pump 18 is depressurized, the internal mixing grouting plug 16 retracts, and then the hoisting system 20 is used to lift the internal mixing grouting plug 16 to the next grouting section via the lifting steel rope 19. This process is repeated until all grouting sections of the hole are completed.

[0037] Therefore, the surface ultra-deep hole directional controlled grouting construction method of the present invention is applicable to the reinforcement and improvement of unfavorable geological conditions in front of the tunnel face under medium and deep burial conditions, before the tunnel face has been excavated to the pre-grouting mileage section. This ensures the safety of construction and structural stability inside the tunnel, and realizes parallel operation of surface pre-grouting reinforcement and tunnel excavation and support construction without interference, which greatly improves the excavation progress efficiency and shortens the construction period.

[0038] The following examples illustrate the application of the construction method of the present invention in engineering.

[0039] The Yinchuan-Xi'an High-Speed ​​Railway traverses the world's largest loess plateau, the Dongzhi Plateau, from south to north. This arid plateau in northern Shaanxi and eastern Gansu is characterized by hills, high plateaus, and ravines, with yellowish-brown folds. It is one of the main areas in my country where collapsible loess is distributed. Groundwater runoff occurs, and groundwater is widely distributed in the middle and late Qing Dynasty clayey loess strata. When the tunnel project crosses the loess plateau in shallow sections, it passes through the groundwater level and soft plastic loess interlayers for a long time. This can easily cause softening and deformation of the surrounding rock due to seepage water, sudden collapse, surface subsidence, and groundwater loss. The difficulties and challenges brought to the project construction are rare in the world.

[0040] The tunnels at the entrance and inclined shaft of the Shangge Village Tunnel on the Yinchuan-Xi'an Railway are buried at depths of 60 to 97 meters. The surrounding rock of the tunnel is Tertiary ancient loess, and the tunnel body passes through soft plastic loess sections. The highest water content of the strata is as high as 33%, and the stability of the surrounding rock is extremely poor. Multiple collapses and deformations have occurred, making the construction extremely risky. It is known in the industry as "excavating in the rain and supporting in the mud" and "building a tunnel in silt".

[0041] After adopting the surface ultra-deep hole directional controlled grouting construction method of the present invention, the water content of the surrounding rock decreased from 31% to 20%, the grout veins at the tunnel face were obvious, the strata were stable, and the excavation effect was good. The maximum values ​​of tunnel surrounding rock settlement and horizontal convergence deformation were reduced by about 60% and 32%, respectively. After reinforcement, the unconfined compressive strength of core samples reached >0.7 MPa. The soil impermeability and bearing capacity were significantly improved, and the plastic state of the soil was effectively improved. Therefore, the invention of the surface ultra-deep hole directional controlled grouting construction method was successful, effectively controlling structural deformation, ensuring construction safety, and enabling the tunnel excavation progress to exceed 70 meters / month, which is twice that before the measures were taken.

[0042] Although preferred embodiments of the invention have been described in detail herein, it should be understood that the invention is not limited to the specific structures and steps described and shown herein, and other variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A method for directional controlled grouting construction in ultra-deep boreholes on the surface, comprising: (1) The targeted grouting valve pipe is manufactured according to the set size requirements. In step (1), the pipe wall of the targeted grouting valve pipe is provided with several rows of overflow holes, and a stop valve sleeve and a stop valve sleeve protector are fitted on each row of overflow holes. The targeted grouting valve pipe includes a first type targeted grouting valve pipe and several second type targeted grouting valve pipes. The diameter and wall thickness of the first type targeted grouting valve pipe and the second type targeted grouting valve pipe are the same. One end of the first type targeted grouting valve pipe is provided with a guide tip, and the other end is provided with an external / internal thread. The two ends of the second type targeted grouting valve pipe are respectively provided with an internal thread and an external thread. (2) Level the construction site, measure and mark the positions of several grouting holes, and drill to the set depth at the marked positions to complete the drilling of all the grouting holes. (3) The targeted grouting valve pipe and the PE pipe are hoisted together into one of the grouting holes, and the casing material is injected into the grouting hole through the PE pipe to seal the gap between the targeted grouting valve pipe and the hole wall of the grouting hole. (4) Connect the internal mixing grouting plug to the pressure pump via the pressure pipe, and connect it to the hoisting system via the lifting steel rope. Connect the grouting core tube to the internal mixing grouting plug and place it into the targeted grouting valve pipe, and lower it to the pre-grouting depth. Use the pressure pump to inflate the internal mixing grouting plug through the pressure pipe. Connect the grouting core tube to the grouting pipeline. Perform backward segmented grouting through the internal mixing grouting plug. In step (4), the grouting liquid has the characteristics of rapid setting and early strength. The initial setting time of single-liquid grout is 25-45 min, and the final setting time is 30-60 min. The initial setting time of double-liquid grout is 30-300 s. (5) After a section of grouting is completed, pull out the internal mixing grouting plug to the next grouting section, and repeat step (4) until all grouting sections of the grouting hole are completed.

2. The surface ultra-deep hole directional controlled grouting construction method as described in claim 1, characterized in that, An outer sleeve joint is welded at the connection of the two second-type targeted grouting valve pipes. The length of the outer sleeve joint is not less than 60 cm, and the inner diameter of the outer sleeve joint is not greater than the outer diameter of the targeted valve pipe by 3 mm.

3. The surface ultra-deep hole directional controlled grouting construction method as described in claim 2, characterized in that, In step (1), the outer diameter of the targeted grouting valve pipe is set to 60 mm, 79 mm or 89 mm.

4. The surface ultra-deep hole directional controlled grouting construction method as described in claim 3, characterized in that, In step (2), the depth of the grouting hole is set to 60 to 300 meters.

5. The surface ultra-deep hole directional controlled grouting construction method as described in claim 4, characterized in that, In step (2), the drilling method is set to high-pressure air drilling, water drilling, or mud wall drilling.

6. The surface ultra-deep hole directional controlled grouting construction method as described in claim 5, characterized in that, In step (3), the shell material is composed of the following raw materials in parts by weight: 100 parts water, 100-200 parts cement, and 100-300 parts bentonite.

7. The surface ultra-deep hole directional controlled grouting construction method as described in claim 6, characterized in that, In step (4), one or two grouting core tubes are provided, and the diameter of the grouting core tube is set to 15 mm or 20 mm.

8. The surface ultra-deep hole directional controlled grouting construction method as described in claim 5, characterized in that, In step (4), the grouting liquid is sulfoaluminate cement single-liquid grout, modified ordinary cement single-liquid grout, or cement-water glass two-liquid grout.

9. The surface ultra-deep hole directional controlled grouting construction method as described in claim 8, characterized in that, In step (4), the segment length of the grouting section is set to 0.75 to 2 meters, and the grouting pressure is set to 1 to 30 MPa.

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