CN109780325B - Installation method of underwater pipeline of water taking tunnel of water plant - Google Patents

Abstract

The invention discloses a method for installing underwater pipelines of water taking tunnels of water plants, which comprises the following steps of laying a protective structure outside a construction area; manufacturing steel buoyancy tanks by steel plates and assembling to form an overwater working platform; constructing an underwater underground tunnel main hole and a tunnel main hole end water stop wall by using a working vertical shaft, and reserving a half joint; carrying out slotting construction on the pipe groove by adopting an underwater blasting and/or excavating mode, leveling the pipe groove after the pipe groove is finished, and tamping the bottom of the pipe groove; after the two ends of the welded water taking pipeline are plugged, the water taking pipeline floats to the center of the pipeline and sinks to a specified position; a diver finely adjusts the water taking pipeline through a manual hoist installed underwater, removes the plug board, and uses an underwater auxiliary butt joint device to butt and connect the water taking pipeline and the pipeline in the tunnel, and underwater concrete pouring is carried out at the butt joint position; and carrying out pipeline backfilling and underwater concrete pouring. The invention has simple construction equipment, good environment-friendly and water-saving effect and quick construction progress.

Description

Installation method of underwater pipeline of water taking tunnel of water plant

Technical Field

The invention relates to a construction method in the field of building construction research, in particular to a method for installing an underwater pipeline of a water-taking tunnel of a water plant.

Background

With the continuous development of the engineering construction cause of China, the tunnel construction technology is continuously mature day by day, and the underwater tunnel is rapidly developed at home and abroad in recent years due to the unique advantages of the underwater tunnel. The developed countries begin research and practice on underwater tunnels very early, while the countries start relatively late at home, but the research and practice on underwater tunnel technology are actively carried out at present, and outstanding results are obtained. The deep comparative analysis of the geological conditions of the underwater tunnel engineering is more complex, has high requirements on engineering water resistance, permeability resistance and engineering service life under different erosion conditions, and simultaneously provides higher requirements for underwater operation of constructors. The construction of the installation of the underwater tunnel and the open cut pipeline is a hotspot and a difficult point in the engineering field of the underwater tunnel, and it is necessary and urgent to evaluate the risk and take scientific and reasonable construction technical measures.

Most of pipeline construction projects in China are land grooving and pipe burying projects, the underwater construction is generally carried out by cofferdam water pumping dry land grooving and pipe burying, immersed tube, jacking pipe or tunnel tunneling method, and the grooving and pipe burying at the bottom of a deep water lake are rare. The underwater pipeline blasting groove at the joint of the open-cut direct-buried pipeline and the tunnel in the underwater deep water area is used for installing the water taking pipeline, and the pipeline connection and environment-friendly requirements are high, and the construction difficulty is high.

The construction of the cofferdam water pumping dry land grooving pipe burying, sinking pipe, jacking pipe or tunneling method is as follows:

1) a technology for slotting and burying pipes in dry land by cofferdam includes such steps as filling water-stop cofferdams at both sides of underwater pipeline, digging pipe ditches in cofferdams after water pumping, installing pipeline in segments by hoisting equipment, and excavating and removing the filled cofferdams by digging machines after filling and covering.

2) The sinking pipe construction technology is a construction method of underwater building tunnel, several prefabricated sections are floated and transported to sea surface (river surface) site respectively, and are sunk and mounted in the dredged foundation trench one by one so as to construct the underwater tunnel by said method. The construction sequence is that tunnel pipe sections (made of steel plates and concrete or reinforced concrete) are firstly manufactured on a slipway or in a dry dock, and the two ends of the pipe sections are sealed by temporary sealing walls, then slide down (or drain water in the dock) to float in the water and then are hauled to the tunnel design position. After positioning, loading is carried out in the pipe section, so that the pipe section sinks into the pre-dug underwater groove. The sections are lowered section by section and adjacent sections are joined by hydraulic crimping. And finally, removing the sealing wall to enable all the pipe sections to be communicated into an integral tunnel.

3) The pipe jacking construction technology overcomes the friction force between a pipeline and surrounding soil by means of jacking force generated by jacking equipment in a working pit, jacks the pipeline into the soil according to a designed gradient and carries away earthwork. After one section of pipe is pushed into the soil layer, the second section of pipe is pushed into the soil layer continuously. The principle is that by means of the thrust of the main top oil cylinder, the pipeline and the relay, the tool pipe or the development machine is pushed into the receiving pit from the working pit through the soil layer and is lifted. The pipeline is buried between the two pits after following the tool pipe or the heading machine.

4) The tunnel driving method construction technology adopts a tunnel driving machine for construction, is called a shield for a soft soil stratum, and is called TBM for a rock stratum, and is comprehensive equipment for carrying out continuous operation by using mechanical rock breaking, mucking and supporting.

The disadvantages of the four aforementioned techniques:

1) the technology of slotting and burying the pipe in the dry land with the cofferdam has the advantages that the workload of cofferdam demolition is high after cofferdam filling and pipeline installation, and the destructiveness to the water environment is high.

2) The immersed tube construction technology needs large hoisting equipment, is complicated in construction link and has great influence on water environment.

3) The pipe jacking construction technology needs to additionally excavate a working well, the soil layer covering the pipeline needs to be thick, and the construction period is long.

4) The tunneling construction technology has high requirement on water leakage prevention, needs a thick covering layer and is not suitable for water taking pipelines with smaller pipe diameters and shorter pipelines.

Disclosure of Invention

The invention aims to provide an underwater pipeline installation method for a water taking tunnel of a water plant, which reduces the workload of cofferdam filling, dismantling, water pumping and water stopping and shortens the construction period.

The solution of the invention for solving the technical problem is as follows: an installation method of underwater pipelines of water taking tunnels of water plants comprises the following steps,

1) laying a protective structure outside the construction area;

2) manufacturing steel buoyancy tanks by steel plates and assembling to form an overwater working platform;

3) constructing an underwater underground tunnel main tunnel and a tunnel main tunnel end water stop wall by using a working vertical shaft, and welding a half joint on a steel pipe reserved at the end part of the tunnel main tunnel in advance;

4) adopting underwater blasting and/or excavation mode to implement slotting construction of pipe slot, after the pipe slot is completed, leveling pipe slot,

tamping the bottom of the tank;

5) after two ends of a welded water taking pipeline are plugged, the water taking pipeline is dragged to float to the central position of the pipeline through the water working platform, and then the water taking pipeline is sunk to a specified position through simultaneous operation of a plurality of water working platforms;

6) a diver finely adjusts the water taking pipeline through a manual hoist installed underwater, removes the plug board, and uses an underwater auxiliary butt joint device to butt and connect the water taking pipeline and the pipeline in the tunnel, and underwater concrete pouring is carried out at the butt joint position;

7) and carrying out pipeline backfilling and underwater concrete pouring.

As a further improvement of the technical scheme, an underwater bubble curtain system is arranged at the water bottom outside 10m around the explosion area, the underwater bubble curtain system comprises three groups of bubble curtains which are arranged in parallel along the periphery of the explosion point, the distance between every two groups of bubble curtains is 0.5m, each group of bubble curtains consists of a bubble curtain launching tube, the bubble curtain launching tubes in the two groups of bubble curtains are filled with air from two ends, and the bubble curtain launching tubes in the other group of bubble curtains are filled with air from the middle.

As a further improvement of the technical scheme, the above-water working platform comprises a drilling reef explosion ship, a dredger, a tugboat, a stone throwing ship, a transport ship and a crane ship.

As a further improvement of the technical scheme, the pipe chase comprises a bell mouth section, an underwater excavation section, an underwater blasting section and a mechanical crushing section, the bell mouth section excavates silt clay and strongly weathered dolomite on the surface layer, a steel pipe inserted into the supporting template is provided with an embedded part, and a platform is poured; directly excavating muddy clay and strongly weathered dolomite on the surface layer in an underwater excavation section, and inserting a steel pipe for supporting a template; the construction of the underwater blasting section adopts a construction process of underwater drilling blasting; and in the construction of the mechanical crushing section, after intensive holes are drilled in a water-drilling mode, a hydraulic crushing hammer and an air compressor are adopted for construction.

As a further improvement of the technical scheme, the mechanical crushing section is positioned at the joint of the underwater pipeline and the tunnel main tunnel.

As a further improvement of the technical scheme, a pipeline fixing steel pipe and a template fixing steel pipe are arranged before pipeline backfilling, a diver carries out combined steel template side die installation after the pipeline is limited, the pipeline is anchored into a rock stratum and fixed by a longitudinal phi 108 × 10mm steel pipe, and then underwater concrete pouring construction is carried out, wherein in the construction, concrete is non-dispersive and self-compacting concrete underwater, and the underwater concrete pouring is carried out by adopting a conduit method.

As a further improvement of the technical scheme, the method comprises the specific steps that elbows are welded at two ends of the extension pipeline, the extension pipeline is transported in a floating mode and sinks to an installation position, the end blocking plates are removed, six groups of divers use an underwater auxiliary butt joint device underwater to successfully butt joint the extension pipeline and the fixed water taking pipeline and joint the extension pipeline and the fixed water taking pipeline, a limiting device is installed, and underwater concrete pouring is carried out on the butt joint position.

As a further improvement of the technical scheme, the protective structure consists of a concrete pier, a phi 108mm steel pipe vertical rod, a nylon woven cloth filter layer, a gravel mesh bag, a floating ball, an oil separation fence and a warning sign, and the protective structure is installed by a diver in cooperation with a floating crane.

The invention has the beneficial effects that:

1) the protective structure ensures the cleanness of the water quality of the I-level water source water body; the bubble curtain system is adopted to greatly weaken the propagation of water shock waves generated by underwater blasting and reduce the damage of the water shock waves to aquatic organisms.

2) The underwater pipeline is formed by processing the pipeline on land, slotting by underwater blasting at the bottom of a deepwater lake, transferring and floating the pipeline by an overwater working platform, sinking the pipeline by a counter weight anti-floating measure, and manually positioning and installing the pipeline and a tunnel joint 14m below the normal water level of a reservoir area, so that the problems of difficult transportation, high underwater welding cost, large construction difficulty and the like of a large-diameter long pipeline are solved, the construction difficulty is reduced, the construction period is shortened, and the investment is saved.

3) The water stop wall at the end of the tunnel main tunnel is constructed at the joint of the underwater pipeline and the tunnel main tunnel, so that water is prevented from flowing into the excavated tunnel after the tunnel main tunnel and the pipeline joint are broken and excavated.

4) The tunnel main tunnel and the adjacent pipe ditch joint are built with a protective arch frame, the rock of the tunnel and the adjacent pipe ditch to be dismantled is drilled with intensive holes under water, and then the rock is impacted and crushed under water by an underwater oil cannon, so that the underwater pipeline is effectively prevented from being damaged.

5) The construction equipment is simple, is suitable for the installation of underwater pipelines with thin covering layers such as reservoirs without large ships, rivers and lakes and the like, and has good environment-friendly and water-saving effects and fast construction progress.

Drawings

In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is clear that the described figures are only some embodiments of the invention, not all embodiments, and that a person skilled in the art can also derive other designs and figures from them without inventive effort.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic longitudinal end view of the underwater explosion section and the mechanical crushing section after concrete is poured.

Detailed Description

The conception, the specific structure, and the technical effects produced by the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings to fully understand the objects, the features, and the effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention. In addition, all the coupling/connection relationships mentioned herein do not mean that the components are directly connected, but mean that a better coupling structure can be formed by adding or reducing coupling accessories according to specific implementation conditions.

Referring to fig. 1 and 2, a method for installing underwater pipelines of water taking tunnels of water plants comprises the following steps,

1) laying a protective structure outside the construction area;

2) manufacturing steel buoyancy tanks by steel plates and assembling to form an overwater working platform;

3) constructing an underwater underground tunnel main tunnel 1 and a tunnel main tunnel end water stop wall 2 by using a working vertical shaft 0, and welding a half joint on a steel pipe reserved at the end part of the tunnel main tunnel 1 in advance;

4) carrying out slotting construction on the pipe groove by adopting an underwater blasting and/or excavating mode, leveling the pipe groove after the pipe groove is finished, and tamping the bottom of the pipe groove;

5) after two ends of the welded water taking pipeline 7 are plugged, the water taking pipeline 7 is pulled to float to the central position of the pipeline through the water working platform, the water taking pipeline 7 is fixed, and the water taking pipeline 7 is sunk to a specified position through simultaneous operation of a plurality of water working platforms;

6) a diver finely adjusts the water taking pipeline 7 through a manual hoist arranged underwater, so that the water taking pipeline is aligned to a welded half joint with a fixed flange in advance, a blanking plate is removed, the water taking pipeline 7 is butted and connected with a pipeline in a tunnel by using an underwater auxiliary butting device, and underwater concrete pouring is carried out at the butted position;

7) and carrying out pipeline backfilling and underwater concrete pouring.

Considering that water can flow into an excavated tunnel after being crushed and excavated, in order to ensure that the water cannot flow into the excavated tunnel after being excavated and influence subsequent construction, a tunnel main tunnel end water-stopping wall 2 with the length of 3m is arranged at the joint of an underwater pipeline and a tunnel main tunnel 1, a super-original excavation surface 1m is excavated at the joint of the underwater pipeline and the tunnel main tunnel 1, an HRB400-22@20 reinforcing mesh is arranged inside the tunnel main tunnel end water-stopping wall, and the middle part of the tunnel main tunnel end water-stopping wall is provided with an HRB400

And the tie bars are arranged according to a quincunx shape of 1m × 1m, and are poured at one time by adopting C30 and S6 concrete.

Considering that the welding quality of the underwater steel pipe cannot be guaranteed, welding half joints on the reserved steel pipe in advance, and facilitating butt joint of the steel pipe after the pipe ditch is broken; after the mechanical crushing reaches the last layer, in order to prevent the hydraulic crushing head and the hooking machine from damaging the pipeline during excavation, the pipeline must be protected in advance, a protective arch frame is built by using square timbers of 20cm around the pipeline, and gaps are filled with sand. The joint of the underwater pipeline of the protective arch frame and the tunnel main tunnel 1.

The underwater bubble curtain system is arranged at the bottom of the water outside 10m around the explosion area and comprises three groups of bubble curtains which are arranged in parallel along the periphery of the explosion point, the distance between every two groups of bubble curtains is 0.5m, each group of bubble curtains consists of a bubble curtain transmitting tube, the bubble curtain transmitting tubes in the two groups of bubble curtains are fed with air from two ends, and the bubble curtain transmitting tubes in the other group of bubble curtains are fed with air from the middle.

Specifically, a bubble curtain system is adopted in a construction area, and three bubble curtains are arranged to greatly weaken the propagation of water-shocking waves and reduce the damage of the water-shocking waves to aquatic organisms. In order to prevent secondary pollution caused by injuring aquatic organisms and reduce the diffusion range of pollutants, the underwater bubble curtain system is adopted in the project.

Before each blasting, an underwater bubble curtain system is arranged at the water bottom outside 10m around the blasting area. Namely, three groups of parallel bubble curtains are arranged along the periphery of the explosion point, the distance between every two groups of bubble curtains is 0.5m, and each group of bubble curtains consists of a bubble curtain transmitting tube. Wherein two groups of bubble curtain launching tubes are used for air inlet from two ends, and the other group of the launching tubes are used for air inlet from the middle, so that the quantity of bubbles is ensured to be uniform. The diameter of the transmitting tube is 32mm, small holes are drilled on the transmitting tube, three rows of small holes are arranged, the aperture of each small hole is 1.5mm, the hole pitch is 10cm, the row pitch is 0.5cm, and the transmitting tube is arranged in a quincunx manner.

And 5min before the underwater explosion is initiated, opening all the air compressor units, directly injecting air into the launching tube, and forming dense bubble groups through small holes in the launching tube. Because the bubbles are light in weight, the dense bubbles rise and expand from the launching tube continuously, and three bubble curtains are formed.

The water working platform comprises a drilling reef explosion ship, a dredger, a tugboat, a stone throwing ship, a transport ship and a crane ship. According to local conditions, the steel buoyancy tanks are manufactured by steel plates and assembled on site to form a drilling reef explosion ship, a dredger, a tugboat, a stone throwing ship, a transport ship, a crane ship and the like, so that the problem that no large ship exists in a reservoir area is solved, and the construction cost is effectively saved.

The pipe chase comprises a bell mouth section 6, an underwater excavation section 5, an underwater blasting section 4 and a mechanical crushing section 3, the bell mouth section 6 excavates and removes superficial muddy clay and strongly weathered dolomite, a steel pipe inserted into a supporting template is provided with an embedded part, and a platform is poured; the underwater excavation section 5 directly excavates and removes the silty clay and the strongly weathered dolomite on the surface layer underwater, and inserts the steel pipe supporting the template; the construction of the underwater blasting section 4 adopts a construction process of underwater drilling blasting; and the mechanical crushing section 3 is constructed by adopting a hydraulic crushing hammer and an air compressor after intensive holes are drilled in water.

The mechanical crushing section 3 is positioned at the joint of the underwater pipeline and the tunnel main tunnel 1.

Before backfilling the pipeline, arranging a pipeline fixing steel pipe and a template fixing steel pipe, installing a combined steel template side die by a diver after limiting the pipeline, fixing the combined steel template side die by utilizing the steel pipe with the diameter of 108mm and the length of 108 × 10mm anchored into a rock stratum, and then performing underwater concrete pouring construction, wherein in the construction, the concrete is non-dispersive and self-compacting concrete underwater, and the underwater concrete pouring is performed by adopting a conduit method.

Splicing the extension pipeline 9 on the water taking pipeline 7, and specifically comprising the following steps of welding elbows at two ends of the extension pipeline 9, carrying out floating transportation and sinking to an installation position, removing the end blocking plates, utilizing underwater auxiliary butt joint devices by six groups of divers underwater to butt joint and connect the extension pipeline 9 and the fixed water taking pipeline 7 successfully, installing a limiting device, and carrying out underwater concrete pouring at the butt joint position.

The isolation belt comprises concrete piers, steel pipe vertical rods with the diameter of 108mm (the wall thickness is 10mm), nylon woven cloth filter layers (isolation nets), gravel net bags, floating balls, oil barriers, warning signs (lamps) and the like, the isolation belt is installed by a diver in cooperation with a floating crane, the concrete piers are C20 concrete and have the size of 0.3 × 0.3.3 0.3 × 0.3m, the steel pipes with the diameter of 108mm (the wall thickness is 10mm) are embedded in the concrete piers and used as the vertical rods, the steel pipes with the length of 2m penetrate into the lake bottom, the concrete piers and the vertical rods are arranged at intervals of 2m, two layers of transverse connecting rods are vertically arranged between the vertical rods and connected through phi 28-mm steel bars, the filter layers are formed by double layers of nylon woven cloth, a phi wire net is sandwiched between the phi steel pipes, the phi wire net is 4m in height, the gravel net bags are hung at the lower parts of the lake bottom, the gravel net bags are tied to the upright columns in the middle parts, the warning signs (lamps) are tied to the upright columns at intervals of 20m, the oil barriers are respectively provided with one oil barrier, the oil barriers are respectively provided with oil absorbent cotton barriers in the type, the oil barriers are respectively 2000 cm.

The construction of the crushing section is as follows:

(1) underground drilling dense hole

And during construction of the pipeline transition section, the construction is carried out after the strength of the sprayed concrete of the tunnel support meets the design strength.

The method comprises the steps of drilling dense holes in a rock mass to be dismantled by using a reef explosion ship, then crushing the rock in a layered mode by using an underwater oil cannon machine, and finally excavating the crushed rock in a layered mode by using a slag removal buoyancy tank. The diameter of the down-drilled dense hole is 115mm, the hole distance is 300mm, and the hole depth is different according to the thickness and the position of the rock. For tunnels, drilling is required to penetrate the surrounding rock above. For the water intake pipe ditch, the drilling is required to drill to the designed pipe ditch bottom 1.5 m. Therefore, the average hole depth of the pipe channel section is 9.5m, and the average hole depth of the tunnel section is 5.5 m.

(2) Underwater mechanical crushing

The underwater mechanical crushing adopts the following operation steps that a bucket of a PC360 excavator on a slag cleaning ship is detached, a GT80 hydraulic crushing hammer is replaced, and an air compressor is matched:

1) and (6) measuring and lofting. And (4) lofting an excavation profile according to an excavation design sideline, marking the excavation profile by using a marker post, and marking the measured original elevation on a topographic map by using a ruler according to the water depth for controlling the excavation elevation.

2) During excavation, crushing is carried out from the end face which is easy to crush from top to bottom in a layering mode, and the layering thickness is 40-50 cm. During construction, a drill rod of the hydraulic rock breaking hammer is vertically pressed on a rock striking face, then the breaking hammer is started, and the rock is broken by using the impact force of the breaking hammer. During crushing, the crushing hammer is always operated within the angle range of 45 degrees.

3) The excavator is matched when the breaking hammer breaks, after each layer is broken, underwater excavation is carried out by using a 0.6m3 hook ship, partial broken slag is directly abandoned on two sides of a pipe ditch, and partial broken slag which cannot be directly abandoned is loaded, transported and unloaded by using 60m3 open mud barge. And (4) measuring the elevation again, and controlling the excavation of the next layer according to the measured elevation until the design requirement is met.

4) And the broken stones are removed in time during the crushing operation, so that the effective operation of the crushing hammer is ensured. When the breaking hammer generates the idle striking phenomenon, the striking position is immediately changed.

5) And lifting the breaking hammer into the air every 5min of striking, and discharging the moisture in the breaking hammer.

6) When the underwater operation is carried out, 1 time of butter is filled every 2 hours. And pressing the drill steel into the lower cylinder body in place, and then filling butter.

In accordance with the above procedure, a rock layer of 5m thickness is subjected to about 10 cycles of operations, namely crushing, breaking stone, and breaking again.

Underwater blasting section 4 pipeline blasting slotting technology

(1) Drilling holes

The construction is carried out by adopting a three-pipe two-drilling method, and the operation process is as follows:

1) after the ship is positioned, firstly, a guide pipe is arranged; then, placing a sleeve;

2) according to the rock surface condition, if the rock surface condition is broken, firstly performing alloy drilling on the casing;

3) after the alloy is drilled into the complete bedrock, lifting the related drilling tool;

4) the lower drill rod is subjected to impact rotary drilling and is drilled to a designed bottom elevation:

5) and measuring the depth of the hole, and if the depth is not deep enough, repeating the steps.

(2) Plug-in when charging

In order to prevent silt and stone slag from silting the hole, the powder is charged immediately after the drilling is finished. Before charging, the quality and depth of the hole wall are checked. And determining the number of adopted detonating bodies according to the hole depth. When the hole depth h is smaller than 4m, 1 detonating body is used for detonating, and when the hole depth h is 4-8 m, 2 detonating bodies are used for detonating. The explosive charge is loaded approximately one meter from the orifice leaving one meter as a plug.

During explosive loading, the explosive is pushed into the hole by the explosive loading rod, broken stones are adopted to block the blast hole after the explosive is confirmed to be loaded in place, and the blocking length is not less than 0.5m and not more than 1.0 m.

(3) Underwater slag removal

According to the characteristics of deeper water depth and the like, underwater blasting slag excavation is carried out by using a 0.6m3 hook boat, part of blasting slag is directly abandoned on two sides of a pipe ditch, and part of blasting slag which cannot be directly abandoned is installed, transported and unloaded by using 60m3 open mud barge. The key of the underwater excavation construction is the operation of the dredger moving positioning and the dredging depth control. The dredger is characterized in that anchor cables are adopted to control the plane position in the construction process, main anchor cables and splayed anchor cables are arranged in the dredger in a construction water area, the main anchor cables are used for controlling the upward and downward displacement of the dredger body, the splayed anchor cables (or transverse anchor cables) are used for controlling the left and right displacement of the dredger body, and buoy marks are arranged at the anchor positions. When the dredger is constructed, the water depth after dredging is detected while excavating, and an excavator driver adjusts the displacement falling ruler and the falling bucket depth according to the detection result and adopts a depth finder to measure until the design requirement is met.

Before excavation, the plane position of the pipeline passing through the river bottom axis is marked by RTK, three fixed positioning mark points are respectively embedded on the axis of the south bank and the axis of the north bank, and obvious on-bank marks are arranged.

When underwater excavation is carried out, buoys are arranged on the water surface every 10m or so to display a central line to be used as a basis for positioning the excavation plane position of the dredger, and water gauges (the zero elevation of the water gauge needs to be detected frequently) are arranged on two banks to be used as a measurement basis for the excavation elevation of each section.

In order to ensure the accuracy of underwater excavation, a specially-assigned person is appointed to observe, and the RTK is adopted to carry out positioning measurement on the dredger so as to ensure that the excavation section and the position of a bucket falling point of the dredger are accurate, thereby avoiding the phenomena of missed excavation and underexcavation, reducing the re-excavation rate, ensuring the construction quality of underwater excavation and improving the working efficiency.

(4) Leveling and acceptance inspection of pipe groove

1) Preliminary acceptance of underwater pipe chase

After the pipe chase excavation is finished, the ultrasonic echo depth sounder is used for detecting the pipe chase, and after the pipe chase is qualified through self-inspection and a topographic map is drawn, the pipe chase is reported and managed for preliminary acceptance inspection. The preliminary acceptance method of the underwater pipe groove comprises the following steps:

a depth finder and a GPS are matched and placed on a boat, the boat (a probe) moves along the central line of a pipe groove, and after the central line of the pipe groove is measured, two side lines of the bottom of the pipe are measured once.

Because the project is in an inland reservoir, the water construction ship can not directly enter the project, and no ship manufacturing resource exists locally. Therefore, the project needs to be transformed into the ship for investment construction. According to local conditions, the steel buoyancy tanks are manufactured by steel plates and assembled on site to form a transport ship, a crane ship, a reef explosion platform and the like, so that the problem that no large ship exists in a reservoir area is solved, and the construction cost is effectively saved.

Manual sampling inspection: and (4) sampling the section at the corresponding mileage, measuring the water depth of the section on the water surface of the section at the corresponding mileage by using a thallium hanger, and calculating the elevation of the bottom of the pipe groove.

Calculating the actual elevation of the pipe bottom of the section according to the elevation of the water surface and the measured water depth, and comparing the actual elevation with the designed elevation to know whether the excavation meets the requirements.

And if the detection result of the pipe bottom elevation is not higher than the corresponding designed pipe bottom elevation, the pipe bottom elevation is qualified, and the parts (local height or low) where the pipe bottom elevation is not detected and the parts (local height or low) where the pipe bottom elevation is detected to be lower than the designed pipe bottom elevation are processed by the next process (pipe groove leveling).

2) Underwater pipe groove cushion layer throwing and leveling construction

When the measuring result (underwater pipe ditch excavation) of the depth finder basically meets the design requirement, the construction of the underwater leveling process can be carried out.

And the ultra-deep pipe trench is tamped by filling stone slag, and then the wiper is pushed by a diver to move forward along the central line of the pipe trench, so that the part higher than the pipe trench can be wiped off. The diver walks around the curette and finds that the lower part (almost all) of the bottom of the pipe is connected with the string barrel through the funnel arranged on the ship to discharge sand (the maximum grain diameter of the cushion material is not more than 10mm) to the preset position of the pipe groove, the top elevation requirement of the sand cushion layer which is dumped and filled is consistent with the bottom elevation of the curette (controlled by the diver) until the flatness of the foundation bed after leveling reaches the design and standard requirements.

After the pipe groove is leveled, the working buoyancy tank is changed into a crane ship and a 3t rammer is configured, and the bottom of the groove is tamped. And after tamping, carrying out flatness inspection, and then carrying out construction of 8 buttresses of the bagged concrete.

The bagged concrete 8 buttress is 1m in thickness and 2m in length, each 5m is provided, and a diver underwater controls the overwater worker to cooperate with the diver to throw and fill the bagged concrete 8 into the underwater pipeline trench through a guide pipe according to the measurement result and the underwater trench condition of underwater actual exploration.

(5) Pipeline delivery, floating transportation and sinking in place

1) Water intake pipeline sending and floating transportation

After the pipeline is welded and assembled in sections on a processing field near the temporary wharf, two sections are formed, wherein one section is 30-40 m in length, the other section is an extension pipeline 9, and the length of the extension pipeline 9 is 15-20 m. And after the nondestructive testing is qualified, temporarily plugging the pipe head by using a plugging plate and a rubber sealing strip to prevent water from entering the pipe.

The surface of the plug plate is provided with an air inlet, an air outlet and a water inlet pipe.

The pipe section is hoisted and sent by a crane, in order to avoid overlarge stress generated by the pipeline under the action of self weight, the arrangement of hoisting points is not more than 15m, and 2 150t automobile hoisting devices are needed.

After the prefabricated pipe section enters water, two towing boats reformed by steel buoyancy tanks are used for towing the pipe section to float to the center of the pipe and fixing the pipe section.

2) Sink of water intake pipeline

① hoisting point layout

During the accounting, the pipeline is supposed to be completely sunk into the bottom of the pipe ditch, the weight of the pipeline, the corrosion prevention, the shroud ring and the like and the buoyancy of the pipeline are mutually offset, the lifting force required by each lifting point is the largest, 20 lifting points are supposed to be used for lifting, the lifting capacity of the winch is 2-4 t, the lifting capacity of each lifting point can reach 20t after the winch passes through the pulley block (3 groups), and the lifting capacity of the winch after the winch passes through the pulley block meets the construction and safety requirements.

Because the stress change of each pipe section is complex in the process of sinking and overturning the whole pipeline, in order to ensure that the whole pipeline is not damaged in the process of sinking, overturning and entering the groove, enough lifting appliances must be configured. When the whole pipeline sinks, the number and the lifting capacity of floating cranes which need to be configured for controlling safe sinking and overturning are calculated and determined according to the length and the dead weight of the whole pipeline and the stress condition of each lifting point during sinking, in order to ensure the uniform stress of the pipeline and avoid the pipeline from being damaged during sinking, a lifting ship is arranged at intervals of about 20m for the pipeline, the pipeline is positioned on the water surface of the axis of a pipe groove by the positioning of the lifting ship, when the strong wind weather is met, large-tonnage ships are respectively configured at key points for ensuring that the whole fleet is not blown away by strong wind, and large iron anchors are configured at the front and the back of the key points to stabilize the whole fleet.

In order to prevent the pipeline from being broken or deformed due to falling impact force or torsion force addition caused by sudden sinking of individual hoisting points in the sinking process due to special accidents, according to practical experience, except for reasonably and scientifically arranging the positions of the hoisting points, the hoisting capacity of a pulley block, a hook, a lifting lug and a steel wire rope in the hoisting tool is 2-3 times larger than the theoretical hoisting capacity, and the single-ship hoisting capacity is required to be not less than 20 t. During construction, the lifting hook is directly hung on the lifting lug, and for the purpose of ensuring the lifting safety of the pipeline, besides the lifting lug, a lifting belt is additionally used for tying a pipe at part of lifting points according to specific conditions, and the lifting belt is hung on the lifting hook so as to prevent the lifting lug from being unexpected, thereby realizing double protection. The hoisting points at both sides are hoisted by shore derrick booms, and the installation height is about 8 m.

② preparation before sinking

And setting a pipeline sinking positioning mark. The elevation of the cross section of the groove and the bottom of the pipe groove after being leveled meets the standard requirement. The pipeline is bound firmly, and the ship body is kept stable. After the traction hoisting equipment is arranged and installed, the trial operation is good. And (5) finishing the installation of the balance weight and checking whether the bolt is fastened or not. The diver is well equipped and ready for launching; all tests are qualified. And (5) finishing the training of the immersed tube personnel, and making immersed tube technology to meet the bottom.

③ sinking pipeline

After the whole pipeline is transversely arranged on the water surface by using the lifting boat, whether the connection between the lifting hooks and the lifting lugs of each lifting point and each auxiliary lifting point is firm or not and whether the plane position of the positioning boat is accurate or not are checked, and in order to ensure the safety of the whole pipeline in the sinking and positioning process, the used positioning boat must be anchored stably so as to ensure that the pipeline is balanced, orderly and gradually sunk and positioned. When each work is ready, the total command length of the field command team can issue a pipe sinking command. The pipeline overturning and sinking sequence is as follows: let the pipeline sink at minimum earlier, then low in proper order to high point sink point department pipeline, at that time, each lifts by crane ship in charge person will in time report the condition of sinking of each hoisting point to the commander of totality at any time, and the commander of totality issues each hoisting point pine cable instruction, and each hoisting point should coordinate the gradual pine cable of operation and make the pipeline upset sink, and until whole pipeline realization upset sinks. And the general command commands each crane ship to loosen the steel wire rope for multiple times according to the exhaust conditions at the two ends of the pipeline, so that the steel pipe gradually sinks by 0.2m each time. The pipeline sinks gradually, and each lifting point is adjusted continuously at the same time so as to ensure the reasonable distribution of each lifting point. When the pipeline is orderly sunk, the pipeline central line and the axial line of the foundation trench are corrected to be measured and monitored, and when the pipeline is close to the bottom of the river bed, a diver is dispatched to check the relative position of the pipeline and the central line of the pipe trench. And commanding each lifting vessel to move so as to gradually align the axis of the foundation trench and the starting and stopping positions of the two banks until the design requirements are basically met. During the pipe sinking process, the traction hoisting equipment is carefully operated, the pipeline at the lowest elevation is designed to be overturned and sunk firstly, the pipe top elevation of each hoisting point is adjusted according to the calculation results of different time periods on site, and the form and the stress of the pipe section are well controlled when the buoyancy generated by the sinking pipe section of the pipeline is basically equal to the sum of the dead weight and the counterweight weight of the pipeline during the pipe sinking operation. In the pipeline sinking process, the crane ship mainly controls the pipeline shape. The sinking speed must be controlled in the sinking process, and meanwhile, all constructors should coordinate with each other to enable the pipeline to sink uniformly, so that the stress of the pipeline is controlled within an allowable range. The length of each cable loosing at each lifting point cannot be too large in the overturning stage, generally is 20-30 cm, the vertical sinking stage can be properly increased after the overturning is completed, but the cable loosing time of each lifting point is consistent, and the phenomenon that the pipeline sinking impulsive force is too large due to the fact that a certain lifting point loosens too long at one time and the stress damage of surrounding lifting points is easily caused is avoided. When the pipeline is overturned and sinks to a position 1m away from the designed tank bottom, a total station is used for checking whether the plane position of each lifting point of the pipeline is consistent with the axis of the designed pipe tank or not, if the plane position is inconsistent with the axis of the designed pipe tank, necessary adjustment is carried out to enable the plane position to meet the requirement until the plane position is accurate, the steel pipe is sunk to the pipe foundation under unified command, and each crane ship loosens the sling to a pre-tightening state and stays at the standby original position. And (3) after the pipe section sinks, the diver needs to check the condition of the whole pipe, if a special problem is found, the diver can contact with a commander in time to research and process the method. If no bad phenomenon is found in underwater inspection, the sinking operation of the pipe section can be completed.

④ attention subsidence

The measurement and positioning are accurate, and the measurement and positioning are frequently corrected and measured in the sinking process; the sinking speed is not too fast; the installation requirements and errors of the underwater pipelines are strictly regulated. The stress, deflection and the like during the sinking process are strictly controlled according to the calculation data, and the situation that the stress, deflection and the like are within the allowable range is ensured. When the pipe section is sunk, the influences of weather and the like need to be considered, and detailed measures for adverse emergencies are formulated. When hoisting, the hoisting equipment at the two ends should keep the pipeline horizontal, and synchronously sink at the bottom of the tank to be in place, and the hoisting equipment is removed after the pipeline is stabilized. And after the immersed tube is in place, stabilizing the tube immediately, namely backfilling the saddle pressing block underwater, and backfilling the stabilized tube when sand and pebbles are carried out after the saddle pressing block is installed.

(6) Pipeline underwater installation

And drilling the steel pipe pile according to the designed position, and guiding the hole site of the drilled steel pipe pile by a diver underwater to perform accurate positioning. And tools such as a hand-operated hoist and the like are installed underwater and are used for fine adjustment of the pipeline in the front-back direction, the left-right direction and the up-down direction in water.

When the tunnel is still in a dry operation condition, the end of the pipeline in the tunnel is welded with an elbow with a fixed flange in advance, and an underwater auxiliary butt joint device is installed.

Because the shape of the bent pipe is difficult to control underwater, the water taking pipe 7 is firstly transported in a floating mode and is sunk to the installation position, then the plug plate is removed, and six groups of divers use the underwater auxiliary butt joint device to butt joint the water taking straight pipe and the pipeline in the tunnel and connect the water taking straight pipe and the pipeline successfully.

After the water taking straight pipe section is successfully connected, a limiting device is installed to prevent the straight pipe from moving and floating upwards. The structural members for fixing are connected by flanges or underwater welding. The pitch of each fixture was designed to be 5m, and a total of 12 fixtures were required.

And the left two ends of the extension straight pipe are welded with elbows, are also transported in a floating manner and sink to the installation position, the end blocking plates are removed, and six groups of divers use underwater auxiliary butt joint devices to butt joint the extension straight pipe with the fixed water taking straight pipe and successfully connect the extension straight pipe with the fixed water taking straight pipe.

After the pipe sections of 20m are successfully connected, a limiting device is installed to prevent the pipe sections from moving and floating upwards. And meanwhile, an auxiliary butt joint device is installed underwater at the pipe head on one side of the trash rack. And leveling the foundation on which the trash rack is installed.

The trash rack is hoisted to the installation position, a diver can enable the pipe head with the bend to penetrate through the reserved U-shaped hole of the trash rack under water, then the trash rack can sink to the leveled foundation, and the trash rack can be fixed after the shape is adjusted.

After the pipeline and the water intake head are connected and limited, anti-floating detection can be carried out on the pipeline.

And after the detection is finished, carrying out underwater concrete construction. The connecting section and the water intake head foundation are required to be cast in situ by underwater concrete, so that the pouring quality is ensured. The non-connecting section can be made of underwater concrete built by bags.

After the work is finished, the overwater working platform is dismantled, and the blasting slag stacked on the two sides is backfilled to the upper part of the pipe trench, so that water flow scouring is reduced.

(7) Pipe groove concrete and backfill

And (4) carrying out underwater pouring construction after limiting the pipeline, wherein the underwater concrete pouring is carried out by adopting a conduit method, and the inner diameter of the conduit is 250 mm. In order to ensure that the first batch of poured concrete can completely seal the bottom and bury the guide pipe below the concrete surface, a concrete pump truck is adopted, and the material is directly discharged through the guide pipe. And before backfilling the outer leakage section of the pipeline, arranging a pipeline fixing steel pipe and a template fixing steel pipe.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that the present invention is not limited to the details of the embodiments shown and described, but is capable of numerous equivalents and substitutions without departing from the spirit of the invention as set forth in the claims appended hereto.

Claims (7)

1. A method for installing an underwater pipeline of a water-taking tunnel of a water plant is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

1) laying a protective structure outside the construction area;

2) manufacturing steel buoyancy tanks by steel plates and assembling to form an overwater working platform;

3) constructing an underwater underground tunnel main tunnel and a tunnel main tunnel end water stop wall by using a working vertical shaft, and welding a half joint on a steel pipe reserved at the end part of the tunnel main tunnel in advance;

4) carrying out slotting construction on the pipe groove by adopting an underwater blasting and/or excavating mode, leveling the pipe groove after the pipe groove is finished, and tamping the bottom of the pipe groove;

5) after two ends of a welded water taking pipeline are plugged, the water taking pipeline is dragged to float to the central position of the pipeline through the water working platform, and then the water taking pipeline is sunk to a specified position through simultaneous operation of a plurality of water working platforms;

6) a diver finely adjusts the water taking pipeline through a manual hoist installed underwater, removes the plug board, and uses an underwater auxiliary butt joint device to butt and connect the water taking pipeline and the pipeline in the tunnel, and underwater concrete pouring is carried out at the butt joint position;

7) and carrying out pipeline backfilling and underwater concrete pouring.

2. The method for installing the underwater pipeline of the tunnel for taking water from the water plant according to claim 1, wherein: the underwater bubble curtain system is arranged at the bottom of the water outside 10m around the explosion area and comprises three groups of bubble curtains which are arranged in parallel along the periphery of the explosion point, the distance between every two groups of bubble curtains is 0.5m, each group of bubble curtains consists of a bubble curtain transmitting tube, the bubble curtain transmitting tubes in the two groups of bubble curtains are fed with air from two ends, and the bubble curtain transmitting tubes in the other group of bubble curtains are fed with air from the middle.

3. The method for installing the underwater pipeline of the tunnel for taking water from the water plant according to claim 1, wherein: the water working platform comprises a drilling reef explosion ship, a dredger, a tugboat, a stone throwing ship, a transport ship and a crane ship.

4. The method for installing the underwater pipeline of the tunnel for taking water from the water plant according to claim 1, wherein: the pipe groove comprises a bell mouth section, an underwater excavation section, an underwater blasting section and a mechanical crushing section, the bell mouth section excavates silty clay and strongly weathered dolomite on the surface layer, a steel pipe inserted into the supporting template is provided with an embedded part, and a platform is poured; directly excavating muddy clay and strongly weathered dolomite on the surface layer in an underwater excavation section, and inserting a steel pipe for supporting a template; the construction of the underwater blasting section adopts a construction process of underwater drilling blasting; and in the construction of the mechanical crushing section, after intensive holes are drilled in a water-drilling mode, a hydraulic crushing hammer and an air compressor are adopted for construction.

5. The method for installing the underwater pipeline of the tunnel for taking water from the water plant according to claim 4, wherein: the mechanical crushing section is positioned at the joint of the underwater pipeline and the tunnel main tunnel.

6. The method for installing the underwater pipeline of the tunnel for taking water from the water plant according to claim 1, wherein: the method comprises the following specific steps that elbows are welded at two ends of the extension pipeline, the extension pipeline is transported in a floating mode and sinks to an installation position, a plug plate is removed, six groups of divers use underwater auxiliary butt joint devices to successfully butt the extension pipeline and a fixed water taking pipeline and connect the extension pipeline and the fixed water taking pipeline, a limiting device is installed, and underwater concrete pouring is carried out on the butt joint position.

7. The method for installing the underwater pipeline of the tunnel for taking water from the water plant according to claim 1, wherein: the protective structure consists of a concrete pier, a phi 108mm steel pipe upright rod, a nylon woven cloth filter layer, a gravel mesh bag, a floating ball, an oil separation fence and a warning sign, and the protective structure is installed by a diver in cooperation with a floating crane.

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