Rapid construction method for loess tunnel grouting pipe

Abstract

The invention discloses a rapid construction method for a loess tunnel grouting pipe. The rapid construction method comprises the following steps that 1, construction preparation is conducted; 2, measuring and positioning; step 3, drilling and lowering a pipe; after the vibratory hammer in the excavating equipment is matched with the grouting pipe in an inserted mode through the connector, the vibratory force of the vibratory hammer is used for applying force to the grouting pipe to conduct drilling and pipe descending, and drilling and pipe descending can be conducted at the same time; the extending section at the front end of the connector can extend into one part of the grouting pipe to play a role in stabilizing and supporting the grouting pipe; when the vibratory hammer is used for hammering and drilling holes by means of the grouting pipe, due to insertion matching, pressure is applied between the connector and the grouting pipe, the connector cannot be separated from the grouting pipe, and after drilling is completed and the vibratory hammer is withdrawn, the connector and the grouting pipe can be rapidly separated. According to the method, the hydraulic breaking hammer of an existing excavator is simply improved, the construction speed is high, the effect is good, few resources are occupied, existing equipment can be fully utilized, and the equipment utilization rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction methods, and particularly to a rapid construction method for grouting pipes in loess tunnels. Background Art

[0002] In tunnel construction, the shallow tunneling method is often adopted, and pre-reinforcement and pre-support measures play a key role in the tunnel construction process. The grouting small pipe is a kind of advanced pre-support technology used in the tunneling construction of tunnel engineering, and plays an important role in the construction of poor sections such as soft and broken strata of tunnels, shallow buried sections, sand layers, portal bias pressure sections, fault fracture zones, and sand and gravel sections. The grouting small pipe is a construction measure in which small pipes with holes in the pipe wall are driven (or inserted after drilling) at a certain angle along the outer contour line of the excavated tunnel or underground project, and grouting liquid is pressed into the pipe at a certain pressure. It can not only pre-reinforce the soil around the chamber, but also play an advanced pre-support role. The construction of the grouting small pipe is simple, and the grouting time is short, achieving the purpose of reinforcement, anti-seepage, and leakage stoppage, so it is widely used.

[0003] Currently, during the construction of grouting small pipes in tunnel engineering, usually, a drilling device is first used to drill holes, and then the pipes are lowered into the holes before grouting can be carried out. Drilling and pipe lowering are two relatively independent construction processes. Grouting can only be carried out after the two processes of drilling and pipe lowering are completed. On the one hand, drilling first and then sending the pipe takes a long time and consumes a large amount of resources. On the other hand, the process is relatively cumbersome, resulting in a problem of low construction efficiency. Summary of the Invention

[0004] Aiming at the above existing technical deficiencies, the purpose of the present invention is to provide a rapid construction method for grouting pipes in loess tunnels.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a rapid construction method for grouting pipes in loess tunnels, which is characterized by including the following steps:

[0007] Step 1: Construction preparation;

[0008] Before construction, the grouting liquid is strictly selected, a proportioning test is carried out and a field test is carried out to determine the grouting parameters; at the same time, the preparation of grouting equipment, the processing of pipes, the preparation of materials, and the preparation of tools are carried out;

[0009] Step 2: Measurement and positioning;

[0010] Using a total station, the drilling positions of the small pipes are measured on the excavation contour line according to the design positions and marked clearly; the number, spacing, and longitudinal lap length of the small pipes should be consistent with the design drawings;

[0011] Step 3: Drilling and pipe lowering;

[0012] After the vibratory hammer in the excavation equipment is inserted and matched with the grouting pipe through the connector, the vibratory force of the vibratory hammer is applied to the grouting pipe for drilling and pipe lowering, and drilling and pipe lowering can be carried out simultaneously.

[0013] The extending section at the front end of the connector can extend into the grouting pipe for a part, playing a role in stabilizing and supporting the grouting pipe.

[0014] When the vibratory hammer uses the grouting pipe for hammering and drilling, due to the insertion and matching, pressure is applied between the connector and the grouting pipe, and the connector will not separate from the grouting pipe. When the drilling is completed and the vibratory hammer is withdrawn, the connector and the grouting pipe can be quickly separated, eliminating the removal operation between the grouting pipe and the connector, and the vibratory hammer can directly cooperate with the next grouting pipe for the next drilling operation.

[0015] Step 4: Preparation before grouting;

[0016] After the pipe is lowered, a section of the small conduit is exposed and supported on the steel frame behind the excavation face, and welded to the steel frame to form a pre-support system.

[0017] Before grouting, spray a certain thickness of concrete first to seal the face and form a grout stop plate.

[0018] Conduct debugging of the grouting pipeline. Connect the high-pressure rubber hose of the grouting pump to the pipe orifice, and stuff the gaps at the pipe orifice with cotton yarn, etc., to ensure that the grout will not leak during grouting; after the pipeline is connected, first check the sealing performance by pressing water, and grouting can be carried out only after meeting the requirements.

[0019] Step 5: Grouting;

[0020] The grouting sequence is from bottom to top, the grout is first thin and then thick, the grouting volume is first large and then small, and the grouting pressure is from small to large; when the pressure reaches the designed final grouting pressure and is stable for 10 - 15 minutes, and the grouting volume reaches more than 80% of the designed grouting volume, the grouting of this hole can be ended.

[0021] The beneficial effects of the present invention are as follows: 1. This method uses a small excavator for hydraulic vibration pipe jacking construction of small grouting conduits, with fast speed, good effect, and less resource occupation. It can make full use of existing equipment and improve the equipment utilization rate.

[0022] 2. This method has little disturbance to the surrounding rock mass, can avoid water soaking the surrounding soil layer during the drilling process, reducing the bearing capacity and causing collapse; at the same time, it improves the safety factor of construction personnel.

[0023] 3. This method requires fewer supporting equipment for construction. Drilling and pipe feeding are carried out simultaneously, with high hole-forming efficiency and shortened construction time of the small grouting conduit. Brief Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is the flow chart of the advanced small pipe construction technology provided in Embodiment 1 of the present invention;

[0026] Figure 2 It is the structural diagram of the small pipe provided in Embodiment 1 of the present invention;

[0027] Figure 3 It is the schematic diagram of the construction of the advanced small pipe provided in Embodiment 1 of the present invention;

[0028] Figure 4 It is the schematic diagram of the construction of the locking foot small pipe provided in Embodiment 1 of the present invention;

[0029] Figure 5 It is the structural diagram of the connector in Step 3 of the rapid construction method of the grouting pipe for the loess tunnel provided in Embodiment 1 of the present invention;

[0030] Figure 6 It is the structural diagram of the cooperation between the connector and the grouting pipe in Step 3 of the rapid construction method of the grouting pipe for the loess tunnel provided in Embodiment 1 of the present invention;

[0031] Figure 7 It is the flow chart of the small pipe grouting technology provided in Embodiment 1 of the present invention.

[0032] Explanation of reference numerals: 1. Φ6 stiffening hoop; 2. Φ8mm hole; 3. mixer; 4. slurry storage tank; 5. pump port pressure gauge; 6. pipeline; 7. mixer; 8. orifice pressure gauge; 9. ball valve; 10. small pipe; 11. formation; 12. grouting pump; 13. excavation equipment. Detailed implementation manners

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0034] Embodiment 1

[0035] As Figure 1 shown, the grouting pipes include advanced small pipes, locking foot small pipes, and base grouting small pipes; this embodiment takes the advanced small pipe as an example for illustration.

[0036] Rapid construction method for grouting pipes in loess tunnels, comprising the following steps:

[0037] Step 1: Construction preparation;

[0038] Before construction, strictly select the grouting liquid, conduct proportioning tests and on-site tests to determine the grouting parameters. At the same time, prepare the grouting equipment, process the pipes, prepare the materials, and prepare the tools.

[0039] The advanced small pipes are used in combination with the steel section steel frames and applied to the advanced grouting pre-support of the arch part in the tunnel sections of grade IV and V surrounding rocks. The longitudinal lap length is not less than 1m. Design parameters of the advanced small pipes: Specification of the advanced long pipes: 3.0m long, Φ42*4mm hot-rolled seamless steel pipe; Circumferential spacing of the small pipes: 35cm or 40cm, Dip angle: external insertion angle 5° - 12°; Grouting material: cement slurry, water-cement ratio 1:1 (by weight).

[0040] The front end of the small pipe is made into a pointed cone shape. Drill holes in a plum blossom pattern every 15cm on the pipe wall, with a hole diameter of 8mm. The length of the tail part is not less than 50cm as the grout stopping section without drilling. Drilling is carried out by mechanical drilling. The spacing of the grouting holes must be positioned and drilled with special fixtures, and it is not allowed to blow holes using electric welding or oxygen and acetylene. See the structure of the small pipe in Figure 2 .

[0041] Step 2: Measurement and positioning;

[0042] Using a total station, measure the drilling positions of the small pipes on the excavation contour line according to the design positions and mark them clearly. The quantity, spacing, and longitudinal lap length of the small pipes shall be consistent with the design drawings.

[0043] As Figure 3 、 5 、shown in Figure 6, Step 3: Drilling and inserting the pipes;

[0044] After the vibrating hammer in the excavation equipment is inserted and matched with the grouting pipe through the connector, use the vibration force of the vibrating hammer to apply force to the grouting pipe for drilling and inserting the pipe. Drilling and inserting the pipe can be carried out simultaneously, greatly improving the construction efficiency. Moreover, the extending section at the front end of the connector can extend into the pipe of the grouting pipe for a part, playing a role in stabilizing and supporting the grouting pipe, and can effectively avoid the deformation of the end face of the grouting pipe during the vibration process, facilitating the subsequent connection of the grout stop valve to the grouting pipe. And when the vibrating hammer uses the grouting pipe for hammering and drilling, due to the insertion and matching, pressure is applied between the connector and the grouting pipe, and the connector will not separate from the grouting pipe. When the drilling is completed and the vibrating hammer is withdrawn, the connector and the grouting pipe can be quickly separated, eliminating the removal operation between the grouting pipe and the connector. The vibrating hammer can directly cooperate with the next grouting pipe for the next drilling operation.

[0045] Step 4: Preparation before grouting;

[0046] After the pipes are inserted, the small conduits are exposed 20 cm and supported on the steel frame behind the excavation face, and welded to the steel frame to form a pre-support system;

[0047] Before grouting, first spray 5 - 10 cm thick concrete to seal the heading face and form a grout stop;

[0048] Conduct debugging of the grouting pipeline. Connect the high-pressure rubber hose of the grouting pump to the pipe orifice, and tightly plug the gaps at the pipe orifice with cotton yarn, etc., to ensure that the grout does not leak during grouting. After the pipeline is connected, first conduct a water pressure test to check the sealing performance, and grouting can be carried out only after meeting the requirements.

[0049] As Figure 7 shown, Step 5: Grouting;

[0050] ⑴ The pressure for injecting cement mortar is 0.5 - 1 MPa. The grouting process is carried out strictly in accordance with the design and construction specifications. The grouting sequence is from bottom to top, the grout is first thin and then thick, the grouting volume is first large and then small, and the grouting pressure is from small to large. The grouting process flow of the small conduit is as follows Figure 5 .

[0051] Grouting parameters:

[0052] Grouting pressure: 0.5 - 1.0 Mpa;

[0053] Cement: P.O42.5 ordinary Portland cement;

[0054] Grouting material: Cement slurry, water-cement ratio 1:1 (by weight);

[0055] ⑵ Grouting end standard. When the pressure reaches the designed final grouting pressure and is stable for 10 - 15 minutes, and the grouting volume reaches more than 80% of the designed grouting volume, the grouting of this hole can be ended.

[0056] Treatment methods for the following abnormal phenomena during grouting:

[0057] ① Grout leakage, that is, the phenomenon that the grout flows out from other holes. When grout leakage occurs, the leaking holes should be blocked in time. When it is the turn of this pipe to be grouted, remove the plug, clear the sundries in the pipe with iron wire or steel bar, and wash it with high-pressure air or water (this process does not need to be carried out for the grouting pipe that flows out grout after the plug is removed), and then grout.

[0058] ② When the pressure suddenly rises during grouting, it may be blocked. The machine should be stopped for inspection. When it is blocked, knock or roll to dredge the grouting pipe. If it cannot be dredged, a supplementary pipe should be installed.

[0059] ③If, during the grouting process, a large amount of grout is injected but the pressure does not increase for a long time, the grout concentration and mix ratio should be adjusted, the gel time should be shortened, and low-pressure grouting with a small pump volume or intermittent grouting should be carried out to allow the grout to stay in the fissures for a relatively long time for gelation.

[0060] Step 6: Effect analysis;

[0061] Keep good grouting records: During the grouting process, fill in the records for each pipe, indicating the grouting pressure, grouting volume, and handle any problems promptly.

[0062] Ensure grouting effect: During the excavation process, observe the grouting effect at any time, analyze the measurement data, and stop work for treatment immediately if any problems are found.

[0063] Materials and equipment

[0064] Main materials

[0065]

[0066] Main equipment

[0067]

[0068]

[0069] This method requires fewer supporting equipment for construction. Drilling and pipe feeding are carried out simultaneously, with high hole-forming efficiency, shortening the construction time of the grouting small pipes and the project duration.

[0070] During the drilling process of this method, the consumption of water resources and electric energy is reduced, saving energy. When using the hydraulic vibration pipe jacking method for construction, only 1 worker is needed to cooperate with the excavator to install the small pipes, while when using the hand-held pneumatic rock drill, 5 people are required to drill simultaneously and 2 people to cooperate with pipe feeding, reducing 6 man-hours per shift, greatly reducing the labor intensity of workers and the project cost at the same time.

[0071] This method causes less disturbance to the surrounding rock mass, can avoid water soaking the surrounding soil layer during the drilling process, reducing the bearing capacity and causing collapse, improving the safety factor of construction workers; and keeping the construction environment inside the tunnel dry at the same time.

[0072] This method uses a small excavator for hydraulic vibration pipe jacking to construct the grouting small pipes with fast speed, good effect, and less resource occupation, and can make full use of the existing equipment to improve the equipment utilization rate.

[0073] Application examples

[0074] Example 1

[0075] Project name: Exit of Xichengshan Tunnel of Tianzhuang Expressway Project

[0076] The total length of the left line of Xichengshan Tunnel is 4048m, and the total length of the right line is 4080m. It is designed as a long double-track tunnel. The shallow-buried section is composed of diluvial loess and gravel of the upper Pleistocene. This construction method has been successfully applied in 88 cycles at the exit of the left line.

[0077] (1) The rapid construction method of grouting pipes in loess tunnels. During the use of the socket in this method, by simply improving the hydraulic breaker of the existing excavator, the construction speed is fast, the effect is good, and the resource occupation is less. The existing equipment can be fully utilized to improve the equipment utilization rate. At the same time, during the construction using the hydraulic vibration pipe jacking method, only 1 worker is needed to cooperate with the excavator to install the small conduit, while 5 people are required to drill holes simultaneously with a handheld pneumatic rock drill, and 2 people are needed to cooperate in feeding the pipe. 6 labors are reduced for each shift, greatly reducing the labor intensity of workers. During the drilling process with a handheld pneumatic rock drill, water easily soaks the surrounding soil layer, reducing the bearing capacity and easily causing collapses. Taking the construction of a 4m-long conduit with a wall thickness of 3.5mm and a pipe diameter of 42mm as an example, the hole-forming efficiency is compared (Table 1).

[0078] Table 1 Comparison of hole-forming efficiency

[0079]

[0080]

[0081] The time for dealing with possible problems such as hole collapse and drill jamming during the drilling process with a handheld pneumatic rock drill is not included in the comparison. It can be seen that the hydraulic vibration pipe jacking method has obvious time advantages.

[0082] (2) Similarly, taking the construction of a 4m-long conduit with a wall thickness of 3.5mm and a pipe diameter of 42mm as an example, the energy consumption of a handheld pneumatic rock drill and the hydraulic vibration pipe jacking method driven by a small excavator is compared (Table 2).

[0083] Table 2 Comparison of energy consumption Only the energy consumption during normal use is listed in the above table. The power consumption of the handheld pneumatic rock drill during construction is 51.46KWh, and the water resource consumption is about 0.5m 3 , while the hydraulic vibration pipe jacking method only consumes 2L of fuel during construction; if the no-load of the air compressor and booster pump, as well as the treatment time for hole collapse and drill jamming are added, the energy consumption advantage of using a small excavator for hydraulic vibration pipe jacking will be even greater.

[0084] (3) The Xichengshan Tunnel has double holes for the left and right lines. Since the left and right holes in the exit section are small clear distance tunnels, the construction needs to be staggered. During the actual construction process, the right hole of the advanced tunnel uses a traditional hand-held pneumatic rock drill to construct the foot-locking anchor pipes, advanced small ducts, peripheral reinforcement grouting pipes, and middle rock reinforcement grouting pipes. The left hole of the subsequent tunnel uses a small excavator with hydraulic vibration pipe jacking to construct the foot-locking anchor pipes, advanced small ducts, peripheral reinforcement grouting pipes, and middle rock reinforcement grouting pipes. During the construction in the loess section, the progress of the left hole is significantly better than that of the right hole. The construction period is shown in Table 3.

[0085] Table 3 Comparison of Construction Period and Cycle Time

[0086]

[0087]

[0088] Using the hydraulic vibration pipe jacking method, the average footage of the heading face is 1.68 m / day; using the hand-held pneumatic rock drill, the average footage of the heading face is 1.33 m / day; after comparison, the footage of the hydraulic vibration pipe jacking method is 0.35 m more per day than that of the hand-held pneumatic rock drill construction. Through the comparison of technical principles and performance indicators, it can be seen that the construction of the grouting small ducts by the hydraulic vibration pipe jacking method of the small excavator greatly reduces the construction cycle time, shortens the construction period, and at the same time improves the safety factor of the construction personnel.

[0089] (4) Through the comparison of Table 1, Table 2, and Table 3, if the right hole uses the hydraulic vibration pipe jacking method to construct the foot-locking anchor pipes, advanced small ducts, peripheral reinforcement grouting pipes, and middle rock reinforcement grouting pipes, the construction period will be shortened by approximately: 83 - 110 / 1.68 = 18 days.

[0090] Calculated based on 70 tunnel workers, with an average salary of 10,000 yuan per month, the loader including fuel cost is calculated at 39,000 yuan per month, the excavator including fuel cost is calculated at 50,000 yuan per month, the wet shotcreting machine rental cost is calculated at 150,000 yuan per month, and the dump truck cost is calculated at 22,000 yuan per month. The daily cost savings are:

[0091] (70 * 10000 + 39000 * 2 + 50000 + 150000 + 22000 * 4) * 18 / 30 = 639,600 yuan

[0092] The management cost is calculated at 15% of the mechanical and labor costs. The cost savings are:

[0093] 639,600 * 0.15 = 95,400 yuan;

[0094] The energy cost savings are: (51.46 * 1.5 + 0.5 * 5 - 2 * 5.8) * ((43 + 9) * 74 + 8 * 221 + 14 * 191 + 25 * 260) = 1,007,100 yuan;

[0095] The amortization expenses of equipment such as air compressors, air and water pipes, and fans are approximately 50,000 yuan, with a total of 1,792,100 yuan;

[0096] After comparison, the construction cost of the hydraulic vibration pipe jacking method is 1,792,100 yuan less than that of the hand-held pneumatic rock drilling construction. The construction of the hydraulic vibration pipe jacking method can greatly reduce the labor intensity of operators, reduce energy consumption, shorten the construction period, and reduce costs, achieving better economic benefits.

[0097] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A rapid construction method for grouting pipes in loess tunnels, characterized in that It includes the following steps: Step 1: Construction preparation; Before construction, strictly select the grouting liquid, conduct proportioning tests and on-site tests to determine the grouting parameters; at the same time, prepare the grouting equipment, process the pipes, prepare the materials, and prepare the tools; Step 2: Measurement and positioning; Using a total station, measure the drilling positions of the small pipes on the excavation contour line according to the design positions and mark them clearly; The quantity, spacing, and longitudinal lap length of the small pipes shall be consistent with the design drawings; Step 3: Drilling and pipe insertion; After the vibrating hammer in the excavation equipment is inserted and matched with the grouting pipe through the connector, use the vibration force of the vibrating hammer to apply force to the grouting pipe for drilling and pipe insertion. Drilling and pipe insertion can be carried out simultaneously; The extending section at the front end of the connector can extend into the pipe of the grouting pipe for a certain part, playing a role in stabilizing and supporting the grouting pipe; When the vibrating hammer uses the grouting pipe for hammering and drilling, due to the insertion and matching, pressure is applied between the connector and the grouting pipe, and the connector will not separate from the grouting pipe. When the drilling is completed and the vibrating hammer is withdrawn, the connector and the grouting pipe can be quickly separated, eliminating the disassembly operation between the grouting pipe and the connector. The vibrating hammer can directly cooperate with the next grouting pipe for the next drilling operation; Step 4: Preparation before grouting; After the pipe insertion is completed, the small pipe is exposed for a certain distance and supported on the steel frame behind the excavation face, and welded to the steel frame to form a pre-support system; Before grouting, spray a certain thickness of concrete first to seal the heading face and form a grout stop plate; Conduct debugging of the grouting pipeline, connect the high-pressure rubber hose of the grouting pump with the pipe orifice, and tightly plug the gaps at the pipe orifice with cotton yarn, etc., to ensure that the grout will not leak during grouting; after the pipeline is connected, first conduct a water pressure test to check the tightness, and grouting can be carried out only after meeting the requirements; Step 5: Grouting; The grouting sequence is from bottom to top. The grout is first thin and then thick, the grouting volume is first large and then small, and the grouting pressure is from small to large; when the pressure reaches the designed final grouting pressure and is stable for 10 - 15 minutes, and the grouting volume reaches more than 80% of the designed grouting volume, the grouting of this hole can be ended.

Images