Wide-hole-pitch double-high-pressure three-pipe method high-spraying diaphragm wall construction method

Abstract

The invention provides a construction method of a wide-pitch double-high-pressure three-pipe method high-pressure-spraying diaphragm wall, the diaphragm wall is located on a reservoir dam foundation and is used for performing anti-seepage reinforcement on the dam foundation, and in order to guarantee normal work of an existing water delivery hole of a reservoir, when drilling is performed on a riding track working face, the drilling pitch is larger than the width of the water delivery hole, so that the wide pitch is formed; according to the construction method, construction of the high-spraying diaphragm wall through the wide-hole-distance double-high-pressure three-pipe method is achieved through the operation method of rotary spraying and swing spraying alternate lifting, in order to guarantee the connection strength during alternate lifting, the lap joint re-spraying mode is adopted, the construction quality and the strength requirement of the diaphragm wall are guaranteed, the construction requirement of the dam diaphragm wall can be fully combined, wide-hole-distance operation is achieved, and the construction efficiency is improved. And the construction efficiency and the construction quality of the diaphragm wall are improved while the normal work of the water delivery hole is not influenced.

Description

[0001] Technical field: The present invention relates to the field of water conservancy projects, and in particular to a wide-hole-spacing double-high-pressure three-pipe method high-pressure spraying anti-seepage wall construction method.

[0002] Background technology: Reservoir is a common form of water conservancy project, which plays an important engineering role. With the increase of reservoir operation time, its engineering performance will decrease, and even run with problems. For such reservoirs, it is often necessary to remove hazards and reinforce them to restore their original engineering performance. In the process of reservoir hazard removal and reinforcement project construction, it is often necessary to treat and reinforce the foundation, and anti-seepage wall is a more commonly used form of foundation reinforcement. There are many ways to construct anti-seepage wall, such as conventional concrete anti-seepage wall construction, high-pressure spraying anti-seepage wall construction, rotary spraying anti-seepage wall construction, etc.

[0003] For reservoirs, the construction of anti-seepage walls has certain requirements for working conditions. During the reinforcement of reservoirs, due to the influence of factors such as the existing buildings on the dam or the water intake buildings passing through the dam body during the risk elimination and reinforcement project, as well as the need to maintain stable operation of the existing structures, the construction of anti-seepage walls will be significantly affected. Conventional construction methods cannot meet the requirements. Therefore, it is necessary to combine the actual operation needs of the reservoir and carry out technical innovation while meeting the normal operation requirements of the reservoir. This can not only achieve the continuity and integrity of the anti-seepage wall construction, but also ensure the normal operation requirements of the reservoir.

[0004] Invention content: In view of the problems of the prior art, the present invention provides a wide-hole-spacing double-high-pressure three-tube method high-pressure spraying anti-seepage wall construction method. On the basis of the double-high-pressure three-tube method jet grouting, the hole diameter and high-pressure spraying construction process are reasonably designed to achieve the simultaneous optimization of reservoir operation and anti-seepage wall construction.

[0005] The present invention provides a method for constructing a wide-hole-spacing double-high-pressure three-tube high-pressure spraying anti-seepage wall, wherein the anti-seepage wall is located at the dam foundation of a reservoir, and the dam foundation is anti-seepage reinforced by the anti-seepage wall. The top of the anti-seepage wall is located at the horseway of the reservoir, and a water delivery tunnel is arranged under the horseway. During the construction of the anti-seepage wall, the water delivery tunnel meets normal working conditions, and is characterized in that the construction method comprises the following steps:

[0006] S1: The drilling rig is in place, fixed on the working surface of the horseway, and the drilling hole is positioned, so that the drill bit is aligned with the center of the drilling hole. The drilling holes located at the water delivery hole are respectively located on both sides of the water delivery hole, and the drilling holes are at a certain distance from the water delivery hole. The water level position and verticality are strictly controlled during the drilling operation, and the drilling depth exceeds the wall depth of the anti-seepage wall; after the drilling is completed, the drilling rig is withdrawn;

[0007] S2: Install the double high pressure three-tube high pressure blasting equipment, including the high pressure blasting trolley, high pressure mud pump, high pressure water pump, injection pipeline, water and electricity joints, gate valves and instruments. After installation, conduct a trial run to ensure normal operation, and then fix the double high pressure three-tube high pressure blasting equipment on the working surface of the horseway;

[0008] S3: Triple pipe lowering. During the lowering process, the pipe is lowered with low pressure to prevent the nozzle from being blocked by mud and sand outside the pipe, ensuring smooth lowering. During the lowering process, compressed air is delivered until the grouting pipe is lowered to the predetermined position. First, the pressure is tested with clean water. If the high-pressure water, air, slurry equipment and pipelines are safe and normal, the cement slurry is mixed and made to start the high-pressure grouting operation.

[0009] S4: The double high-pressure rotary spraying operation of the shotcrete pipe stops after the rotary spraying reaches the set height; the lower shotcrete pipe performs swing spraying operation, and stops after the swing spraying is lifted to the set height;

[0010] S5: The lower shotcrete pipe performs double high-pressure rotary spraying. During the operation, it is necessary to overlap the working surface where the last rotary spraying was stopped for a set distance and then spray again. After the rotary spraying reaches the set height, the operation is stopped. The lower shotcrete pipe performs swing spraying. During the operation, it is necessary to overlap the working surface where the last swing spraying was stopped for a set distance and then spray again. After the swing spraying is lifted to the set height, the operation is stopped.

[0011] S6: Repeat step S5 until the designed top elevation of the high pressure injection cut-off wall is reached;

[0012] S7: The double high pressure three-pipe method high pressure spraying equipment moves to the next hole position, and steps S3-S6 are repeated until the construction of the anti-seepage wall is completed;

[0013] Preferably, the specific gravity of the cement slurry for swing spraying is 1.4 g / cm3, the water pressure is 35-40 MPa, the air pressure is 0.8-1.2 MPa, the swing spraying angle is 30°, the lifting speed is 3 cm / min, and the swing speed is 12 times / min.

[0014] Preferably, in S1, the horizontal position deviation of the borehole does not exceed 5 cm, the verticality is controlled at 1% of the borehole depth, and the borehole depth exceeds the wall depth of the anti-seepage wall by not less than 0.3 m.

[0015] Preferably, in step S6, when the shotcrete pipe is lifted to 0.5 m from the orifice, the high-pressure equipment is stopped to prevent injuries to construction workers.

[0016] Preferably, after step S7, it also includes: 3 days after the completion of construction, excavating 1.5m downward from the working surface to detect the quality of the anti-seepage wall, the wall quality indicators include wall thickness, swing spraying diameter, and swing spraying overlap width. When the wall quality indicators meet the specified requirements, the anti-seepage wall construction is completed. When the wall quality indicators do not meet the specified requirements, the anti-seepage wall is reworked until the wall quality indicators meet the specified requirements.

[0017] Preferably, the center distance of the wide-hole-spacing drill holes is not less than 2.5 m, and the drill holes are arranged at equal intervals.

[0018] Preferably, the set height in S4 and S5 is 5m.

[0019] The working principle of the present invention is as follows:

[0020] The construction of anti-seepage walls needs to overcome the existing problems of underground water diversion holes. By expanding the drilling hole spacing to form a wide hole spacing operation, the "large-aperture pilot hole rotary spraying → small-angle swing spraying → repeated spraying" alternating lifting method can be used to increase the hole spacing from the conventional 1.0-1.4m to a wide hole spacing operation, while solving the problem of substandard wall thickness near the anti-seepage wall grouting holes due to small-angle swing spraying (less than 30°). Compared with the conventional grouting construction process after the construction site is repaired, this method reduces the factors that increase the construction period, such as excavation and backfilling, demolition and reconstruction, machine movement, drilling positioning, and grouting hole sequence, and greatly improves the arrangement range of the high-pressure spraying anti-seepage wall grouting hole spacing, which can effectively maintain the integrity and use function of the on-site structure and reduce the disturbance and damage to the surrounding environment.

[0021] The new construction method relying on the combination of large-aperture pilot holes, repeated injection, alternating lifting and other process techniques can improve the liquid and plastic state of the reinforced body, effectively reduce the along-the-way resistance coefficient and head loss of the slurry during the jet grouting process, and at the same time realize construction operations under wide hole spacing. Under the premise of the normal operation of existing buildings (water transfer tunnels), the overall construction of the anti-seepage wall is guaranteed, thereby improving the construction quality and efficiency of the anti-seepage wall.

[0022] The advantages of the present invention are:

[0023] The present invention provides a construction method for a high-pressure jetting anti-seepage wall using a wide hole spacing double high-pressure three-tube method. The anti-seepage wall is located at a reservoir dam foundation and is used for anti-seepage reinforcement of the dam foundation. To ensure the normal operation of an existing water diversion tunnel in the reservoir, when drilling holes on a horseway operation surface, the hole spacing of the drilled holes is made greater than the width of the water diversion tunnel to form a wide hole spacing. The operation method of alternately lifting by rotary jetting and swing jetting is used to realize the construction of a high-pressure jetting anti-seepage wall using a wide hole spacing double high-pressure three-tube method. To ensure the connection strength during alternate lifting, an overlapping and re-spraying method is used to ensure the construction quality and strength requirements of the anti-seepage wall. The construction method can fully combine the construction requirements of the dam anti-seepage wall to realize wide hole spacing operation, and improve the construction efficiency and construction quality of the anti-seepage wall without affecting the normal operation of the water diversion tunnel. Description of the drawings:

[0024] Figure 1 This is a schematic diagram of the anti-seepage wall structure;

[0025] Figure 2 The following is a flow chart of the construction method.

[0026] Specific implementation method: The following is a specific explanation of the contents defined in the present invention with reference to the contents of the drawings in the specification.

[0027] The present invention provides a construction method of a wide-hole-spacing double-high-pressure three-tube high-pressure spraying anti-seepage wall 1, wherein the anti-seepage wall 1 is located at the dam foundation of a reservoir, and the dam foundation is anti-seepage reinforced by the anti-seepage wall 1. The top of the anti-seepage wall 1 is located at the horseway of the reservoir, and a water delivery tunnel is arranged under the horseway. During the construction of the anti-seepage wall 1, the water delivery tunnel meets normal operation, and is characterized in that the construction method comprises the following steps:

[0028] S1: The drilling rig is in place, fixed on the working surface of the horseway, and the drilling hole is positioned, so that the drill bit is aligned with the center of the drilling hole. The drilling holes located at the water delivery hole are respectively located on both sides of the water delivery hole, and the drilling holes are at a certain distance from the water delivery hole. The water level position and verticality are strictly controlled during the drilling operation, and the drilling depth exceeds the wall depth of the anti-seepage wall 1; after the drilling is completed, the drilling rig is evacuated;

[0029] S2: Install the double high pressure three-tube high pressure blasting equipment, including the high pressure blasting trolley, high pressure mud pump, high pressure water pump, injection pipeline, water and electricity joints, gate valves and instruments. After installation, conduct a trial run to ensure normal operation, and then fix the double high pressure three-tube high pressure blasting equipment on the working surface of the horseway;

[0030] S3: Triple pipe lowering. During the lowering process, the pipe is lowered with low pressure to prevent the nozzle from being blocked by mud and sand outside the pipe, ensuring smooth lowering. During the lowering process, compressed air is delivered until the grouting pipe is lowered to the predetermined position. First, the pressure is tested with clean water. If the high-pressure water, air, slurry equipment and pipelines are safe and normal, the cement slurry is mixed and made to start the high-pressure grouting operation.

[0031] S4: The double high-pressure rotary spraying operation of the shotcrete pipe stops after the rotary spraying reaches the set height; the lower shotcrete pipe performs swing spraying operation, and stops after the swing spraying is lifted to the set height;

[0032] S5: The lower shotcrete pipe performs double high-pressure rotary spraying. During the operation, it is necessary to overlap the working surface where the last rotary spraying was stopped for a set distance and then spray again. After the rotary spraying reaches the set height, the operation is stopped. The lower shotcrete pipe performs swing spraying. During the operation, it is necessary to overlap the working surface where the last swing spraying was stopped for a set distance and then spray again. After the swing spraying is lifted to the set height, the operation is stopped.

[0033] S6: Repeat step S5 until the designed top elevation of the high-pressure injection cut-off wall 1 is reached;

[0034] S7: The double high pressure three-pipe method high pressure spraying equipment moves to the next hole position, and steps S3-S6 are repeated until the construction of the cut-off wall 1 is completed;

[0035] Preferably, the specific gravity of the cement slurry sprayed by the oscillating spraying is 1.4 g / cm 3, water pressure is 35-40MPa, air pressure is 0.8-1.2Mpa, swing spray angle is 30°, lifting speed is 3cm / min, and swing speed is 12 times / min. The parameters of the rotary spraying should be reasonably determined according to the test, and the lifting speed is controlled at 3cm / min to prevent the construction quality from being reduced due to excessive lifting.

[0036] Preferably, in S1, the horizontal position deviation of the borehole does not exceed 5 cm, the verticality is controlled at 1% of the borehole depth, and the borehole depth exceeds the wall depth of the anti-seepage wall 1 by not less than 0.3 m. The position and number of the boreholes can be selected according to specific construction requirements. In step S1, the drilling rig is preferably evacuated after all the boreholes are drilled. When cross-operation is required, construction machinery and personnel should be reasonably arranged. The construction site should be leveled before the drilling rig is in place, and a drainage ditch should be excavated on one side to ensure that there is no water accumulation on the site; when the surface is too soft, measures should be taken to prevent the pile driver from becoming unstable.

[0037] Preferably, the starting positions of the swing spraying and rotary spraying in S4 should be at the same depth to ensure the integrity of the anti-seepage wall 1. During cyclic lifting, the starting working surface and the stopping working surface of the rotary spraying and swing spraying are also at the same depth.

[0038] Preferably, in step S6, when the shotcrete pipe is lifted to 0.5 m from the orifice, the high-pressure equipment is stopped to prevent injuries to construction workers.

[0039] Preferably, after step S7, it also includes: 3 days after the completion of construction, excavating 1.5m downward from the working surface to detect the wall quality of the anti-seepage wall 1, the wall quality indicators include wall thickness, swing spray diameter, and swing spray overlap width. When the wall quality indicators meet the specified requirements, the construction of the anti-seepage wall 1 is completed. When the wall quality indicators do not meet the specified requirements, the anti-seepage wall 1 is reworked until the wall quality indicators meet the specified requirements.

[0040] Preferably, the center distance of the wide-hole-spacing drill holes is not less than 2.5 m, and the drill holes are arranged at equal intervals.

[0041] Preferably, the set height in S4 and S5 is 5m. Preferably, when the rotary jetting and swing jetting are within the depth range of the water tunnel, the pressure of the rotary jetting and swing jetting should be adaptively adjusted to ensure the normal operation and stress of the water tunnel structure.

[0042] The engineering example of the present invention is applied to a reservoir on a tributary of the Yellow River. The reservoir is a medium-sized reservoir mainly used for flood control and irrigation, combined with power generation, aquaculture and other comprehensive uses. The main contents of the risk elimination and reinforcement project mainly include: dam reinforcement, anti-seepage, reconstruction of spillway, new water diversion tunnel, reconstruction of bridge across spillway, etc. Affected by the fact that the existing water diversion tunnel currently supplies water normally and needs to be completely preserved (the water diversion tunnel corridor is located about 22m below the first-level horse road), traditional construction technology cannot form an effective continuous anti-seepage wall under the wide mortar-stone corridor of the water diversion tunnel.

[0043] The Quaternary strata are widely distributed in the dam site area, mainly composed of loess-like silty loam of the Quaternary Pleistocene alluvial origin and silty loam layers and pebbles of the Quaternary Holocene alluvial and flood-proluvial origin. No large-scale fault structures have been found in the dam site area. The original terrain of the dam foundation in the riverbed section is relatively flat, and the dam foundation is mainly pebbles, with loess-like silty loam layers underneath.

[0044] During construction, a comprehensive inspection is carried out on the performance of various mechanical equipment; a depth marking line of each meter is accurately drawn on the impact drill, the position of the "zero" starting point is accurately marked when the drill bit falls to the ground, and a plumb bob is hung on the front and side of the frame, and the center position of the plumb bob is marked with red paint.

[0045] The installation of auxiliary equipment of the double high-pressure three-pipe high-pressure spraying equipment should meet the following requirements: ① The pulping machine should be slightly higher than the upper opening of the slurry storage tank; ② The slurry inlet of the high-pressure mud pump must be equipped with a filter and slightly lower than the outlet of the slurry storage tank; ③ The high-pressure mud pump and the spray pipe must be connected with a high-pressure hose. After installation, the high-pressure equipment and pipeline system must be checked again to ensure that the specifications meet the design requirements and the connection seal is intact. And try to shorten the length of the high-pressure grouting pipe, preferably within 50m.

[0046] After the equipment is installed, it must be tested to ensure that it is in good condition and operates normally. The equipment test run should meet the following requirements:

[0047] (1) The speed and lifting speed of the high-pressure spraying trolley meet the design requirements, with an error within 5%;

[0048] (2) The operating voltage and current of the equipment are stable, the voltage is maintained at 380V±15V, and the current does not exceed the rated value;

[0049] (3) The delivery and injection pipelines are unobstructed and leak-free; the gate valves are in normal use; and the pressure, flow and other instruments display correctly;

[0050] (4) The motors of high-pressure mud pumps, high-pressure water pumps, and air compressors reach the set speed and can maintain the set pump pressure; the slurry discharge volume meets the design flow rate;

[0051] (5) The slurry preparation capacity of the slurry preparation and storage equipment meets the grouting requirements;

[0052] (6) The equipment runs smoothly and the operators cooperate well with each other.

[0053] During high-pressure grouting, high-pressure grouting should be sprayed in situ according to the specified parameters first. After the cement slurry returns to the hole mouth, the situation is normal, and the slurry replacement in the hole is completed, it can be started from bottom to top according to the process test parameters, alternating rotary spraying and swing spraying operations. Pay attention to check the slurry initial setting time, grouting flow, pressure, swing spraying angle and lifting speed and other parameters and record them, which should comply with the requirements of the operating procedures. Start the high-pressure grouting pump, water pump, and air pump to start grouting. When the grouting pressure and motor speed are stable and reach the test design parameters, start lifting the grouting rod according to the test design lifting speed and swing spraying angle, and lift while swinging (rotating) spraying.

[0054] After the grouting reaches the designed height from bottom to top, stop the grouting and pull out the grouting pipe. The grouting is finished. Fill the grouting hole with slurry and remove the excess. However, it is necessary to prevent the shrinkage of the slurry when it solidifies. The pipe should be pulled out in time and should not be left in the hole for a long time, otherwise it will be difficult to pull out after the slurry solidifies. When the grouting is finished, clean the high-pressure pump, slurry pipeline, grouting pipe and nozzle immediately.

[0055] In order to minimize the ineffective waste of cement slurry, the remaining construction time of the hole position can be calculated during the high-pressure jet grouting construction process, and the next large-diameter pilot hole can be completed in advance to seamlessly connect the construction of two grouting holes. When drilling is suspended or the final hole is waiting for spraying, the hole mouth should be protected and measures should be taken to prevent hole collapse.

[0056] The construction method of the present invention was used to complete the construction of the high-pressure spraying anti-seepage wall 1. After geological radar, core drilling, permeability coefficient and other items were tested and qualified, the high-pressure spraying anti-seepage wall 1 of this section was continuous and uniform, meeting the design requirements, and the overall construction process was in a safe, stable, fast, high-quality and controllable state. The construction period was shortened by 16 days compared with the original plan, the project quality met the design and specification requirements, and no safety accidents occurred.

[0057] The above-mentioned embodiments are only preferred embodiments of the present invention. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the concept of the present invention.

Claims

1. A method for constructing a high-pressure spraying anti-seepage wall with a wide hole spacing and double high pressure three-tube method, wherein the anti-seepage wall is located at the dam foundation of a reservoir, and the dam foundation is reinforced by the anti-seepage wall. The top of the anti-seepage wall is located at the horseway of the reservoir, and a water transfer tunnel is arranged under the horseway. During the construction of the anti-seepage wall, the water transfer tunnel meets normal operation, and is characterized in that: The construction method comprises the following steps: S1: The drilling rig is in place, fixed on the working surface of the horseway, and the drilling hole is positioned, so that the drill bit is aligned with the center of the drilling hole. The drilling holes located at the water delivery hole are respectively located on both sides of the water delivery hole, and the drilling holes are at a certain distance from the water delivery hole. The water level position and verticality are strictly controlled during the drilling operation, and the drilling depth exceeds the wall depth of the anti-seepage wall; after the drilling is completed, the drilling rig is withdrawn; S2: Install the double high pressure three-tube high pressure blasting equipment, including the high pressure blasting trolley, high pressure mud pump, high pressure water pump, injection pipeline, water and electricity joints, gate valves and instruments. After installation, conduct a trial run to ensure normal operation, and then fix the double high pressure three-tube high pressure blasting equipment on the working surface of the horseway; S3: Triple pipe lowering. During the lowering process, the pipe is lowered with low pressure to prevent the nozzle from being blocked by mud and sand outside the pipe, ensuring smooth lowering. During the lowering process, compressed air is delivered until the grouting pipe is lowered to the predetermined position. First, the pressure is tested with clean water. If the high-pressure water, air, slurry equipment and pipelines are safe and normal, the cement slurry is mixed and made to start the high-pressure grouting operation. S4: The double high-pressure rotary spraying operation of the shotcrete pipe stops after the rotary spraying reaches the set height; the lower shotcrete pipe performs swing spraying operation, and stops after the swing spraying is lifted to the set height; S5: The lower shotcrete pipe performs double high-pressure rotary spraying. During the operation, it is necessary to overlap the working surface where the last rotary spraying was stopped for a set distance and then spray again. After the rotary spraying reaches the set height, the operation is stopped. The lower shotcrete pipe performs swing spraying. During the operation, it is necessary to overlap the working surface where the last swing spraying was stopped for a set distance and then spray again. After the swing spraying is lifted to the set height, the operation is stopped. S6: Repeat step S5 until the designed top elevation of the high pressure injection cut-off wall is reached; S7: The double high pressure three-pipe method high pressure spraying equipment moves to the next hole position, and steps S3-S6 are repeated until the construction of the anti-seepage wall is completed.

2. The wide-hole-spacing double-high-pressure three-pipe method high-pressure spraying anti-seepage wall construction method according to claim 1, characterized in that: The specific gravity of the cement slurry sprayed by the oscillating spraying is 1.4 g / cm 3 , the water pressure is 35-40MPa, the air pressure is 0.8-1.2Mpa, the swing spray angle is 30°, the lifting speed is 3cm / min, and the swing speed is 12 times / min.

3. The wide-hole-spacing double-high-pressure three-pipe method high-pressure spraying anti-seepage wall construction method according to claim 1, characterized in that: In S1, the horizontal position deviation of the drill hole does not exceed 5 cm, the verticality is controlled at 1% of the drill hole depth, and the drill hole depth exceeds the wall depth of the anti-seepage wall by no less than 0.3 m.

4. The wide-hole-spacing double-high-pressure three-pipe method high-pressure spraying anti-seepage wall construction method according to claim 1, characterized in that: In step S6, when the shotcrete pipe is lifted to 0.5 m from the orifice, the high-pressure equipment is stopped to prevent injuries to construction workers.

5. The wide-hole-spacing double-high-pressure three-pipe high-pressure spraying anti-seepage wall construction method according to claim 1, characterized in that: After step S7, it also includes: 3 days after the completion of construction, excavate 1.5m downward from the working surface to detect the quality of the anti-seepage wall. The wall quality indicators include wall thickness, swing spray diameter, and swing spray overlap width. When the wall quality indicators meet the specified requirements, the anti-seepage wall construction is completed. When the wall quality indicators do not meet the specified requirements, the anti-seepage wall is reworked until the wall quality indicators meet the specified requirements.

6. The wide-hole-spacing double-high-pressure three-pipe method high-pressure spraying anti-seepage wall construction method according to claim 1, characterized in that: The center distance of the wide-hole-pitch drill holes is not less than 2.5 m, and the drill holes are arranged at equal intervals.

7. The wide-hole-spacing double-high-pressure three-pipe method high-pressure spraying anti-seepage wall construction method according to claim 1, characterized in that: The set height in S4 and S5 is 5m.

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