CN110984158A

CN110984158A - Offshore wind power large-diameter rock-socketed single pile grouting construction method

Info

Publication number: CN110984158A
Application number: CN201911160272.7A
Authority: CN
Inventors: 朱嵘华; 李庆东; 其他发明人请求不公开姓名
Original assignee: Guangdong Huayun Offshore Wind Power Technology Co Ltd
Current assignee: Guangdong Huayun Offshore Wind Power Technology Co Ltd
Priority date: 2019-11-23
Filing date: 2019-11-23
Publication date: 2020-04-10

Abstract

A construction method for grouting large-diameter rock-socketed single piles of offshore wind power belongs to the technical field of foundation grouting of offshore wind power. The construction method is used for grouting construction of large-diameter rock-socketed single piles in offshore wind power plant construction, solves the problems of bottom sealing and side wall grouting in the grouting construction process, and overcomes the technical defects of a common grouting method. The difficult problem of back cover that the major diameter single pile brought has been solved through the grout back cover, through the even arrangement of prefabricated grout pipe in the steel-pipe pile, the inhomogeneous problem of major diameter steel-pipe pile grout material distribution has been solved, the application of emergent grout pipe, the risk that makes the grout is very reduced, the steel protects a section of thick bamboo promotion and the coordinated action of grout, the appearance of the ageing phenomenon of cohering of steel casing and grout material has been avoided, make the steel protect a section of thick bamboo can reuse, marine wind power infrastructure's cost has been reduced, the security of marine wind power foundation construction has been improved.

Description

Offshore wind power large-diameter rock-socketed single pile grouting construction method

Technical Field

The invention relates to a grouting construction method for a large-diameter rock-socketed single pile of offshore wind power, and belongs to the technical field of offshore wind power foundation grouting.

Background

In the offshore wind power development process, the geological conditions of some fields are complex, the shallow surface layer is a soft covering soil layer, and a hard rock layer is arranged below the covering layer. If the surface layer earthing is only squeezed into to the pile foundation of major diameter single pile basis, the bearing capacity that the pile foundation provided can't satisfy the demand, in order to satisfy the designing requirement of bearing capacity, major diameter single pile foundation pile point portion need imbed in the rock layer under the overburden layer, forms the embedded rock stake.

The rock-socketed pile is constructed by drilling and sinking the pile, and the diameter of the pile hole generated by drilling is larger than that of the single pile, so that the large-diameter single pile can be directly implanted into the drilling hole in the follow-up process. There is the space between steel-pipe pile outer wall and stake hole, need fill the space between steel-pipe pile and the stake hole through the grout of certain intensity, treat that the grout is ageing back, guarantee the bearing capacity and the steadiness of single pile to resist the impact of fan load and external environment load. The particularity of the rock-socketed single pile construction brings a series of technical problems to grouting operation: (1) the grouting of the rock-socketed single pile is finished underwater, the grouting clearance is small, and the underwater monitoring difficulty is high; (2) the diameter of a single pile reaches several meters, the use of a rubber ring or a steel plate for bottom sealing is high in cost, the method is complex, the effect is difficult to guarantee, failure is easy to occur once collision occurs in the installation process, and if the bottom sealing fails, grouting material flows into the pile barrel, so that a large amount of grouting material is wasted; (3) in the drilling and tunneling process, a steel casing needs to be lowered to ensure that the soft soil of the upper surface covering layer cannot collapse in the drilling process, the progress between the steel casing and grouting operation needs to be coordinated and promoted in the side wall grouting process, if the steel casing is promoted too fast, the soft soil of the upper surface covering layer is disturbed, the drilling collapse is easily caused, if the steel casing is promoted too slowly, grouting materials are condensed, the steel casing and a steel pipe pile are bonded together, and the steel casing is difficult to pull out, so that an engineering accident is caused; (4) the length of the grouting section of the rock-socketed single pile reaches dozens of meters, the grouting amount is large, and grouting needs to be finished by bottom grouting and bottom sealing and pile soil side wall gap grouting. Therefore, the reasonable grouting construction method has important significance for the safety and the economical efficiency of rock-socketed single pile construction.

Disclosure of Invention

In order to solve the technical problem, the invention provides a grouting construction method for a large-diameter rock-socketed single pile of offshore wind power, which is used for grouting construction of the large-diameter rock-socketed single pile in offshore wind power plant construction. The grouting method solves the difficult problems of bottom sealing and side wall grouting in the grouting construction process, and overcomes the technical defects of the common grouting method.

The technical scheme adopted by the invention is as follows: a construction method for grouting large-diameter rock-socketed single piles of offshore wind power plants comprises the following steps:

(a) arranging the steel casing in the mud layer according to the design requirement, wherein the bottom of the steel casing is in contact with the rock stratum, and the top of the steel casing is higher than the sea level;

(b) emptying a mud layer in the pile casing on the inner side of the steel pile casing and a lower rock stratum of the pile casing at the bottom of the steel pile casing;

(c) hoisting a prefabricated steel pipe pile into a steel casing by using a crane for positioning, and forming an annular cavity between a rock wall formed by the steel pipe pile and an empty rock stratum under the steel casing and the steel casing;

(d) hoisting a grouting pipe into the steel pipe pile and extending to the bottom of the pile hole, pumping grouting material to a position which is 500mm away from the bottom of the pile hole by the grouting pipe so that the grouting material is filled at the bottom of the steel pipe pile, lifting the grouting pipe at a constant speed in the subsequent grouting process (lifting the grouting pipe by a crane on a construction ship when grouting at a certain height), enabling a grouting opening of the grouting pipe to be always positioned at a position which is 150 mm below the surface of the grouting material, stopping grouting when the grouting is performed until the thickness of the grouting material is 1000 mm and 1100mm, removing the grouting pipe, lifting the steel pipe pile, enabling the grouting material to enter an annular cavity, then laying the pile down, standing for 24h, and forming a bottom sealing grouting layer after the grouting material is aged;

(e) hoisting the emergency grouting pipe into the annular cavity, wherein the upper interface of the emergency grouting opening of the emergency grouting pipe, which is higher than the bottom sealing grouting layer, is 400-500 mm; grouting the annular cavity through the first prefabricated grouting pipe, grouting the annular cavity by using the second prefabricated grouting pipe when the slurry surface in the annular cavity rises to a second grouting opening of the second prefabricated grouting pipe until the slurry surface of the annular cavity rises to the position of a mud surface, and stopping grouting the annular cavity; in the process of grouting the annular cavity by using the first prefabricated grouting pipe and the second prefabricated grouting pipe, when the slurry surface in the annular cavity is higher than the mudstone boundary surface, the emergency grouting pipe and the steel protective barrel are lifted at a constant speed, so that the emergency grouting opening of the emergency grouting pipe is always higher than the slurry surface of the annular cavity by 400-plus-500 mm (the lifting speed of a grouting interface is calculated according to the grouting volume of the annular cavity and the production capacity of grouting equipment, and the emergency grouting pipe is lifted by using a crane according to the lifting speed); only when the first prefabricated grouting pipe and the second prefabricated grouting pipe cannot be grouted due to faults, the emergency grouting pipe is used for grouting the annular cavity, and the emergency grouting pipe is enabled to intermittently move around the steel pipe pile in the annular cavity while grouting;

(f) and when the slurry surface of the annular cavity rises to the position of the mud surface, the steel protecting cylinder is lifted away from the mud layer, and the steel protecting cylinder is recovered.

The inner wall of the steel pipe pile is provided with a first prefabricated grouting pipe fixed by a plurality of first supporting rods) and a second prefabricated grouting pipe fixed by a plurality of second supporting rods, the first prefabricated grouting pipe is communicated with a first grouting opening arranged on the pile wall, and the second prefabricated grouting pipe is communicated with a second grouting opening arranged on the pile wall.

The second grouting opening is located above the first grouting opening, and the distance between the first grouting opening and the bottom end of the steel pipe pile is 1200-1300 mm.

The invention has the beneficial effects that: the offshore wind power large-diameter rock-socketed single pile grouting construction method solves the bottom sealing problem caused by large-diameter single piles through grouting material bottom sealing, solves the problem of uneven distribution of grouting materials of large-diameter steel pipe piles through uniform arrangement of prefabricated grouting pipes in the steel pipe piles, and reduces the grouting risk greatly by applying emergency grouting pipes.

Drawings

Fig. 1 is a structural view of a precast grout pipe of a steel pipe pile.

FIG. 2 is a cross-sectional view taken along line I-I of FIG. 1.

FIG. 3 is a sectional view taken along line II-II in FIG. 1.

FIG. 4 is a schematic diagram of a steel casing driving into a mud layer and emptying the mud layer and the rock layer below the casing.

Fig. 5 is a schematic view of the installation and positioning of the steel pipe pile in the steel casing.

Fig. 6 is a schematic view of forming a back-cover grouting layer by grouting a bottom of a steel pipe pile with a grouting pipe.

Fig. 7 is a schematic illustration of grouting an annular cavity with a pre-fabricated grout tube in a steel pipe pile.

Figure 8 is a schematic illustration of completion of annular cavity grouting.

In the figure: 1. the device comprises a steel pipe pile, a steel casing, a 2a protective casing inner mud layer, a 2b protective casing lower rock stratum, a 3, a first prefabricated grouting pipe, a 3a first supporting rod, a 3b first grouting opening, a 4, a second prefabricated grouting pipe, a 4a second supporting rod, a 4b second grouting opening, a 5, a grouting pipe, a 5a grouting opening, a 6, an emergency grouting pipe, a 6a emergency grouting opening, a 7, a bottom sealing grouting layer, a 8 and an annular cavity; A. a mud layer, a B rock layer, a C mudstone interface, a D mudface.

Detailed Description

The grouting construction method of the offshore wind power large-diameter rock-socketed single pile is further explained below with reference to the accompanying drawings.

Fig. 1, 2 and 3 show the structure of the prefabricated grouting pipe of the steel pipe pile. Be equipped with two first prefabricated grout pipes 3 that fix with a plurality of first bracing pieces 3a and two prefabricated grout pipes 4 of second that fix with a plurality of second bracing pieces 4a on the inner wall of steel-pipe pile 1, first prefabricated grout pipe 3 and the alternate equipartition of second prefabricated grout pipe 4 are on the inner wall of steel-pipe pile 1. The first prefabricated grouting pipe 3 is communicated with a first grouting opening 3b formed in the pile wall, and the second prefabricated grouting pipe 4 is communicated with a second grouting opening 4b formed in the pile wall. The second grouting opening 4b is positioned above the first grouting opening 3b, and the distance between the first grouting opening 3b and the bottom end of the steel pipe pile 1 is 1200-1300 mm.

As shown in fig. 4 and 5, the bottom end of the steel casing 2 is driven into the mud layer a, the bottom of the steel casing is in contact with the rock stratum B, the top end of the steel casing 2 is located above the horizontal plane, a pile hole is dug under the protection of the steel casing 2, and the mud layer 2a in the steel casing 2 and the rock stratum 2B under the steel casing 2 at the bottom of the steel casing 2 are emptied. And then, sinking the steel pipe pile 1 into the excavated pile hole, wherein annular cavities 8 between the steel pipe pile 1 and the rock hole wall and between the steel pipe pile 1 and the steel casing 2 are positions needing grouting and backfilling.

After the steel pipe pile 1 is sunk to a preset elevation and leveled, the grouting pipe 5 is lowered to a position 300-500mm away from the pile bottom, as shown in fig. 6. Pumping grouting material to the inside of the steel pipe pile 1 by using the grouting pipe 5, enabling the grouting material to fill the bottom of the steel pipe pile 1, lifting the grouting pipe 5 at a constant speed in the subsequent grouting process, enabling a grouting opening 5a of the grouting pipe 5 to be always located at the position of 150-sand-adding 250mm below the grout surface, stopping grouting when the thickness of the grouting material is 1000-sand-adding 1100mm, removing the grouting pipe 5, lifting the steel pipe pile 1, enabling the grouting material to enter an annular cavity 8, then putting down the steel pipe pile 1, standing for 24 hours, and forming a bottom-sealing grouting layer 7 after the grouting material is aged.

As shown in fig. 7, the emergency grouting pipe 6 is lowered in the annular cavity 8 between the steel pipe pile 1 and the steel casing 2 to a position 400-500mm above the bottom sealing grouting layer 7. At first, grout ring cavity 8 through first prefabricated grout pipe 3, when the thick liquids face in ring cavity 8 risees to the second grout mouth 4a of prefabricated grout pipe 4 of second, change to use prefabricated grout pipe 4 of second to grout ring cavity 8, rise to the position of mud face D until the thick liquids face of ring cavity 8, stop 8 grout in ring cavity 8. In the process of grouting the annular cavity 8 by using the first prefabricated grouting pipe 3 and the second prefabricated grouting pipe 4, when the slurry surface in the annular cavity 8 is higher than a mudstone interface C, the emergency grouting pipe 6 and the steel casing 2 are required to be lifted at a constant speed, so that the emergency grouting opening 6a of the emergency grouting pipe 6 is always higher than the slurry surface 400-500mm of the annular cavity 8. Only when the first prefabricated grouting pipe 3 and the second prefabricated grouting pipe 4 cannot be grouted due to faults, the emergency grouting pipe 6 is used for grouting the annular cavity 8, and the emergency grouting pipe 6 is enabled to intermittently move around the steel pipe pile 1 in the annular cavity 8 while grouting.

As shown in fig. 8, when the slurry level in the annular chamber 8 rises to the position of the mud level D, the steel casing 2 is lifted away from the mud layer a, and the steel casing 2 is recovered.

The offshore wind power large-diameter rock-socketed single pile grouting construction method provided by the invention is explained above. The above cases are intended to help the skilled person understand the method and its core ideas referred to in the present invention. It should be noted that those skilled in the art can make modifications necessary to the present invention without departing from the principle of the present invention, and such modifications are also within the scope of the appended claims.

Claims

1. A construction method for grouting large-diameter rock-socketed single piles of offshore wind power plants is characterized by comprising the following steps: the method comprises the following steps:

(a) arranging the steel casing (2) in the mud layer (A) according to the design requirement, wherein the bottom of the steel casing is in contact with the rock layer (B), and the top of the steel casing is higher than the horizontal plane;

(b) emptying a casing inner mud layer (2 a) at the inner side of the steel casing (2) and a casing lower rock stratum (2 b) at the bottom of the steel casing (2);

(c) hoisting a prefabricated steel pipe pile (1) into a steel casing (2) by using a crane for positioning, and forming an annular cavity (8) between a rock wall formed by the steel pipe pile (1) and an empty lower rock stratum (2 b) of the casing and the steel casing (2);

(d) the method comprises the steps that a steel pile grouting pipe (5) is hung into a steel pipe pile (1) and extends to the bottom of a pile hole, grouting materials are pumped to the bottom of the pile hole through the steel pile grouting pipe (5) and have the thickness of 300-250 mm, so that the grouting materials are filled in the bottom of the steel pipe pile (1), the steel pile grouting pipe (5) is lifted at a constant speed in the subsequent grouting process, a steel pile grouting opening (5 a) of the steel pile grouting pipe (5) is always located 150-250mm below a slurry surface, grouting is stopped until the thickness of the slurry is 1000-1100mm, grouting is stopped, the steel pile grouting pipe (5) is removed, the steel pipe pile (1) is lifted, the grouting materials enter an annular cavity (8), the steel pipe pile (1) is placed down, standing is carried out for 24 hours, and a bottom sealing grouting layer (7) is formed after the grouting materials are aged;

(e) the emergency grouting pipe (6) is hung in the annular cavity (8), and the upper interface of the emergency grouting opening (6 a) of the emergency grouting pipe (6) which is higher than the bottom sealing grouting layer (7) is 400-plus-500 mm; grouting an annular cavity (8) through a first prefabricated grouting pipe (3), when the slurry level in the annular cavity (8) rises to a second grouting opening (4 a) of a second prefabricated grouting pipe (4), grouting the annular cavity (8) by using the second prefabricated grouting pipe (4) until the slurry level of the annular cavity (8) rises to the position of a mud surface (D), and stopping grouting the annular cavity (8); in the process of grouting the annular cavity (8) by using the first prefabricated grouting pipe (3) and the second prefabricated grouting pipe (4), when the slurry surface in the annular cavity (8) is higher than a mudstone interface (C), the emergency grouting pipe (6) and the steel casing (2) are lifted at a constant speed, so that the emergency grouting opening (6 a) of the emergency grouting pipe (6) is always 400-500mm higher than the slurry surface of the annular cavity (8); only when the first prefabricated grouting pipe (3) and the second prefabricated grouting pipe (4) cannot be grouted due to faults, the emergency grouting pipe (6) is used for grouting the annular cavity (8), and the emergency grouting pipe (6) is enabled to intermittently move around the steel pipe pile (1) in the annular cavity (8) while grouting;

(f) when the slurry surface in the annular cavity (8) rises to the position of the mud surface (D), the steel casing (2) is lifted away from the mud layer (A) to recover the steel casing (2).

2. The offshore wind power large-diameter rock-socketed single pile grouting construction method according to claim 1, characterized by comprising the following steps: be equipped with on the inner wall of steel-pipe pile (1) with first prefabricated grout pipe (3) that a plurality of first bracing pieces (3 a) are fixed and with prefabricated grout pipe (4) of second that a plurality of second bracing pieces (4 a) are fixed, first prefabricated grout pipe (3) and first grout mouth (3 b) the intercommunication of setting on the pile wall, prefabricated grout pipe of second (4) and second grout mouth (4 b) the intercommunication of setting on the pile wall.

3. The offshore wind power large-diameter rock-socketed single pile grouting construction method according to claim 2, characterized by comprising the following steps: the second grouting opening (4 b) is positioned above the first grouting opening (3 b), and the distance between the first grouting opening (3 b) and the bottom end of the steel pipe pile (1) is 1200-1300 mm.