Plate-sand geology inclined pile sinking method

Abstract

The invention provides a plate-sand geology inclined pile sinking method which is used for jacket construction under the condition that a steel pipe pile is self-sunk and basically does not enter mud, a rear pile method is adopted for construction, and after the jacket is in place, the steel pipe pile is inserted; the method comprises the following steps: S1, construction preparation and sea sweeping; s2, a hoisting ship and a transport ship are in place; s3, the jacket is hoisted and leveled in place; and S4, steel pipe pile hoisting, pile inserting and pile driving are conducted. The device has the following advantages that after the steel pipe pile sinks, the vibratory hammer clamps an upper opening of the pipe pile, and friction between the pipe pile and a jacket in the pile sinking process can be effectively avoided; the steel pipe pile is driven into mud by the vibratory hammer and then is driven by the hydraulic hammer, so that the occurrence of pile deformation can be effectively avoided; according to the construction method, the overall safety coefficient of construction is improved.

Description

Technical Field

[0001] The present invention relates to the field of offshore new energy, and particularly to a method for driving inclined piles in sandy geological formations. Background Art

[0002] As an important part of green energy, offshore wind power has now entered the stage of large-scale development. The electric energy generated by all wind turbines is collected here and connected to the power grid on land through submarine cables for transmission to thousands of households. The construction of the jacket, which is the main structural component supporting the offshore substation, is the key point of the entire wind farm construction.

[0003] Most of the jacket foundations of domestic substations are in the form of vertical piles. After pre-construction using the pre-piling method or the post-piling method, the foundation small piles are connected to the jacket structure through grouting. After the grouting material solidifies, the upper structure of the substation is installed on the jacket. The small piles of this type of jacket foundation indirectly bear the pressure of the upper structure, so the structural stability is not high.

[0004] The structural form of the inclined pile jacket is that the upper structure of the substation directly presses on 4 inclined piles, and the grouting part is only for fixing the jacket structure. Therefore, the overall stability is relatively high after the upper structure of the substation is hoisted in place.

[0005] In the design of the jacket of an offshore new energy power plant substation, from a structural perspective, the inclined piles have relatively high stability, but at the same time, there are relatively large difficulties in the pile driving process. For example, when the steel pipe piles are basically zero in the mud and in a non-vertical state, directly using a hydraulic hammer for pile driving, the situation of uneven force and excessive swing of the steel pipe piles occurs, and the steel pipe piles are prone to irreversible bending deformation.

[0006] In view of this, the inventor of the present application has designed a method for driving inclined piles in sandy geological formations in order to overcome the above technical problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects in the prior art that the inclined pile driving process is difficult, prone to uneven force and excessive swing of the steel pipe piles, and the steel pipe piles are prone to irreversible bending deformation, and to provide a method for driving inclined piles in sandy geological formations.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] A method for driving inclined piles in sandy geological formations, characterized in that the method for driving inclined piles in sandy geological formations is used for jacket construction when the steel pipe piles are basically zero in the mud, and the post-piling method is adopted for construction. After the jacket is in place, the steel pipe piles are inserted.

[0010] It includes the following steps:

[0011] S 1, Construction preparation and sea sweeping;

[0012] S 2 , Hoisting vessel and transportation vessel in place;

[0013] S 3 , Jacket hoisting, leveling and in place;

[0014] S 4 , Steel pipe pile hoisting, pile insertion and pile driving.

[0015] According to an embodiment of the present invention, the pile insertion in the step S 4 includes: Hoisting the steel pipe pile to the installation position above the jacket conduit for pile insertion.

[0016] According to an embodiment of the present invention, the guide blocks of the jacket are used during the pile insertion process to ensure the inclination of the pile.

[0017] According to an embodiment of the present invention, the guide blocks are pre-installed and polished to a length of 5 m.

[0018] According to an embodiment of the present invention, the pile driving in the step S 4 includes:

[0019] S 41 , Inserting the steel pipe pile into the jacket column;

[0020] S 42 , Lifting the vibratory hammer, keeping the inclination of the hammer and the pile the same, clamping the hammer to the steel pipe pile, and then starting the vibratory hammer;

[0021] S 43 , When the steel pipe pile enters the mud by one-third, replace it with a hydraulic hammer for hammering.

[0022] According to an embodiment of the present invention, the pile driving in the step S 4 also includes:

[0023] S 44 , Starting the hydraulic hammer to continue pile driving, and adjusting the hammering energy according to the mud penetration speed of the pile body during the pile driving process;

[0024] S 45 , When the steel pipe pile enters the mud to about 1.5 m from the top of the jacket to the lifting lug, stop hammering, and then cut off and polish the lifting lug smoothly;

[0025] S 46 , Continue hammering to the pre-designed depth.

[0026] According to an embodiment of the present invention, the hydraulic hammer in the step S 44 first hammers at 10% of the energy, and then makes adjustments according to the penetration degree.

[0027] According to an embodiment of the present invention, a guide block is provided on the bottom arm of the hammer cap of the hydraulic hammer in the step S 43 In the

[0028] According to an embodiment of the present invention, the maximum stress during the pile driving process is less than or equal to 250 MPa, the maximum static stress of the pile hammer pressing the pile is less than or equal to 100 MPa, and the maximum combined stress acting on the pile body is less than or equal to 350 MPa.

[0029] According to an embodiment of the present invention, the method for driving inclined piles in sandy soil also includes: vibration hammer pile driving analysis;

[0030]

[0031]

[0032] Where: F 0 Is the exciting force of the vibration hammer; W 0 Is the total weight of the vibration hammer; P is the total weight of the steel pipe pile; ω is the angular velocity; K is the eccentric moment.

[0033] The positive and progressive effects of the present invention are as follows:

[0034] The method for driving inclined piles in sandy soil of the present invention has the following many advantages:

[0035] First, after the steel pipe pile sinks by itself, the vibration hammer clamps the upper mouth of the pipe pile, which can effectively avoid friction between the pipe pile and the jacket during the pile driving process;

[0036] Second, after the steel pipe pile is driven into the mud by the vibration hammer, the hydraulic hammer is used to drive the pile, which can effectively avoid the occurrence of pile deformation;

[0037] Third, this construction method improves the overall safety factor of the construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, where the same reference numerals in the drawings always represent the same features, where:

[0039] Figure 1 Is a schematic structural diagram of the jacket in the method for driving inclined piles in sandy soil of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the drawings.

[0041] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the present invention will now be described in detail, and examples thereof are shown in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0042] In addition, although the terms used in the present invention are selected from well-known and commonly used terms, some of the terms mentioned in the specification of the present invention may be selected by the applicant according to his or her judgment, and the detailed meanings thereof are described in the relevant parts of the description herein.

[0043] In addition, it is required to understand the present invention not only by the actual terms used, but also by the meaning implied by each term.

[0044] Figure 1 It is a schematic structural diagram of the jacket for the inclined pile driving method of the sandy geological plate in the present invention.

[0045] As Figure 1 shown, the following jacket is taken as an example in this embodiment:

[0046] The elevation of the top of the jacket foundation is 12.2 m, the elevation of the top platform is 10.7 m, the center distance between the main conduits is 20.46 m (length) × 17.36 m (width), the elevation of the bottom of the jacket is -12.3 m, the elevation of the bottom plane is -11 m, the center distance between the main conduits is 24.8 m (length) × 23.7 m (width), the height from the top to the bottom of the jacket is 24.5 m, and the mass is about 736 t.

[0047] The diameters of the 4 steel pipe piles of the jacket are 1.8 m, the designed pile length is 86.346 m (5 m is lengthened during fabrication for easy driving of the steel pipe, and the actual pile length is 91.346 m), the penetration depth into the mud is about 61 m, and the designed weight of a single pile is about 182 t (about 155 t after lengthening by 5 m).

[0048] The construction sea area is located in the inner shelf sea area of the South China Sea, with a coastal facies deposit. The engineering properties of the upper soil layer in the field area are relatively good. There are 1 - 3 layers of silty sand, slightly dense to medium dense, with the top depth of the layer being 0 m, the top elevation being -11.70 m to -11.10 m, and the layer thickness being 1.00 m to 1.90 m. There is 1 layer of fine sand, dense, with the top depth of the layer being 0 - 1.90 m, the top elevation being -13.60 m to -12.15 m, and the layer thickness being 9.60 m to 12.70 m.

[0049] The present invention discloses an inclined pile driving method for sandy geological plates, which is used for jacket construction when the self - sinking of steel pipe piles results in almost zero penetration into the mud. The post - pile method is adopted for construction. After the jacket is in place, the steel pipe piles are inserted;

[0050] It includes the following steps:

[0051] Step S 1, Construction preparation and sea sweeping.

[0052] Step S 2 , Positioning of the lifting vessel and the transportation vessel.

[0053] Step S 3 , Lifting, leveling and positioning of the jacket.

[0054] Step S 4 , Lifting, inserting and driving of steel pipe piles.

[0055] Preferably, in the said Step S 4 , the pile insertion includes: lifting the steel pipe pile to the installation position above the jacket conduits for pile insertion.

[0056] During the pile insertion process, the guide blocks of the jacket are used to ensure the inclination of the pile. The guide blocks are pre-installed and polished and lengthened to 5m.

[0057] After the floating crane vessel lifts the steel pipe pile, it sends the steel pipe pile to the installation position above the main conduits of the jacket through operations such as slewing and luffing for pile insertion. During pile insertion, the jacket itself is equivalent to a "pile gripper". During the pile insertion process, the pre-installed 5m lengthening of the jacket in the factory and the guide block device welded to the upper and lower parts of the inclined pipe section are used to ensure the inclination angle of the pile. At the same time, 4 guide blocks are installed on the outside of the top of the main conduits of the jacket. When the guide blocks are processed and manufactured, the surface is required to be polished smoothly and there should be no sudden edges and corners to prevent the pile from being stuck in the main conduit during pile insertion and unable to be adjusted, and at the same time, the clearance between the steel pipe pile and the main conduit frame also meets the design requirements.

[0058] Next, pile driving is carried out. The order of pile driving will be determined according to the order of pile insertion. Drive 1 pile immediately after inserting 1 pile. Since the on-site situation is constantly changing, the order of pile sinking should be adjusted according to the actual situation.

[0059] When driving the pile, when the steel pipe pile enters the mud is basically zero, if directly using a hydraulic hammer to drive the pile, the hammer impact force is likely to cause bending deformation at the extrusion part between the steel pipe pile and the jacket. Therefore, the pile sinking is carried out in 2 steps, that is, first use a vibratory hammer EP1600 to make the steel pipe pile sink preliminarily about one-third of the pile length, and then replace it with an IHCS800 hydraulic hammer to hammer and sink it to the design depth.

[0060] Preferably, in the said Step S 4 , the pile driving includes:

[0061] Step S 41 , Insert the steel pipe pile into the columns of the jacket.

[0062] Measure the elevation of the top of the jacket, and determine the pile driving order according to the measurement results.

[0063] Step S 42, hoist the vibratory hammer, keep the inclination of the hammer and the pile the same, clamp the steel pipe pile with the hammer, and then start the vibratory hammer.

[0064] For example, use the auxiliary hook to hoist the EP1600 vibratory hammer, keep the inclination angle of the hammer the same as the inclination angle of the pile with the horizontal plane, clamp the engineering pile with the hammer, and then start the vibratory hammer.

[0065] Step S 43 , when the steel pipe pile penetrates into the mud by one-third, replace it with a hydraulic hammer for hammering.

[0066] Among them, in the said step S 43 , a guide block is provided on the bottom arm of the hammer cap of the hydraulic hammer.

[0067] Here, the hydraulic hammer is preferably an IHCS800 hydraulic hammer. To make the pile hammer smoothly fit into the steel pipe pile, a guide block is welded to the bottom arm of the hammer cap, and a temporary lifting lug is used on the outside and a steel wire rope is installed in the lug to adjust the inclination of the hammer cap and the hammer rod to match the pile body through a crane.

[0068] Even more preferably, the pile driving in the said step S 4 also includes:

[0069] Step S 44 , start the hydraulic hammer to continue pile driving. During pile driving, adjust the hammering energy according to the penetration speed of the pile body into the mud. This can ensure the penetration degree of the pile.

[0070] Among them, according to the IHC-S800 operation manual, and at the same time to ensure that the deformation of the pile body is within the controllable range, in the said step S 44 , the hydraulic hammer first hammers at 10% of the energy (for example, 80 kJ), then makes appropriate adjustments according to the penetration degree, and timely adjusts the size of the hammering energy as the pile continuously penetrates.

[0071] Step S 45 , when the steel pipe pile penetrates into the mud to about 1.5 m from the top of the catheter of the lifting lug, stop hammering, and then cut off the lifting lug and polish it smoothly.

[0072] Step S 46 , continue hammering to the pre-designed depth.

[0073] Repeat the above steps to hammer other pile pipes, and measure the top elevation of the jacket after completion.

[0074] The maximum stress during the pile driving process is less than or equal to 250 MPa, the maximum static stress of the pile hammer pressing the pile is less than or equal to 100 MPa, and the maximum combined stress acting on the pile body is less than or equal to 350 MPa.

[0075] In addition, the method for driving inclined piles in sandy soil also includes: vibratory hammer pile driving analysis;

[0076]

[0077]

[0078] In the formula: F 0 is the exciting force of the vibratory hammer; W 0 is the total weight of the vibratory hammer; P is the total weight of the steel pipe pile; ω is the angular velocity; K is the eccentric moment.

[0079] To ensure the smooth sinking of the steel piles for the booster station foundation, the strength of the steel piles during pile driving operations with a vibratory hammer and an IHCS-800 hydraulic hammer is evaluated under different mud penetration depths of the steel piles.

[0080] When driving piles with a vibratory hammer, the weight acting on the pile top is 60t. Through the pile sinking analysis of the vibratory hammer (such as the EP1600 vibratory hammer), the following conclusions are obtained:

[0081] First, the amplitude of the vibratory hammer, 4.19 mm, is greater than the critical amplitude of 3 mm;

[0082] Second, the exciting force of the vibratory hammer, 700t, is greater than the dynamic lateral resistance of the pile, 542t;

[0083] Third, the total mass of the pile hammer, 296t, is greater than the dynamic end resistance of 0.6t;

[0084] Fourth, the power consumed by the pile-soil interaction is less than 1.5 times the power of the motor.

[0085] Meeting the above four conditions, the vibratory hammer (such as the EP1600 vibratory hammer) can successfully complete the pile sinking construction task.

[0086] In the method for driving inclined piles in the sandy geological formation of the present invention, the key to lifting and driving the inclined piles is the control of the force on the hook head. If the force is too small, it is easy to cause excessive deformation of the steel pipe pile. At the same time, the steel pipe pile at the contact position with the jacket is easily crushed, and the load borne by the jacket is relatively large, making it prone to large vibrations. If the force is too large, it is easy to change the inclination of the steel pipe pile, making the inclination of the steel pipe pile not meet the design requirements. At the same time, it will also contact the other side of the jacket pipe barrel structure, generating a large frictional resistance.

[0087] In the construction method of the inclined pile jacket in the sandy geological formation, the self-sinking depth of the steel pipe pile inserted into the sandy geological formation is very small or basically does not enter the mud. After the self-sinking of the steel pipe pile is completed, if a hydraulic hammer is directly used for pile sinking, it is very easy to cause excessive deflection of the steel pipe pile and plastic deformation under extrusion. Also, due to the inclined pile structure, the hydraulic hammer is easily damaged when the steel pipe pile slides. Therefore, the method for driving inclined piles in the sandy geological formation of the present invention effectively solves the above possible problems.

[0088] In summary, the method for driving inclined piles in the sandy geological formation of the present invention has the following many advantages:

[0089] 1. After the steel pipe pile sinks by itself, the vibrating hammer clamps the upper opening of the pipe pile, which can effectively avoid the friction between the pipe pile and the jacket during the pile sinking process;

[0090] 2. After the steel pipe pile is driven into the mud by the vibrating hammer for a certain depth, then use the hydraulic hammer to drive the pile, which can effectively avoid the occurrence of pile deformation;

[0091] 3. This construction method improves the overall safety factor of the construction.

[0092] For those skilled in the art, the above invention disclosure is only an example and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0093] At the same time, this application uses specific terms to describe the embodiments of this application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0094] Similarly, it should be noted that in order to simplify the description of this application disclosure and thus help the understanding of one or more embodiments of the invention, in the previous description of the embodiments of this application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the subject of this application are more than those mentioned in the claims. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0095] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for driving inclined piles in sandy silt geological formations, Characterized in that, The method for driving inclined piles in sandy silt geological formations is used for jacket construction when the steel pipe piles are self-sinking with basically zero penetration into the mud, and the post-piling method is adopted for construction. After the jacket is in place, the steel pipe piles are inserted; It includes the following steps: S 1 , Construction preparation and sea sweeping; S 2 and the hoisting ship and the transport ship are in place; S 3 , lifting, leveling and positioning of jacket; S 4 , hoisting, inserting and driving of steel pipe piles.

2. The method for driving inclined piles in sandy silt geological formations according to claim 1, Characterized in that, The described step S 4 The pile insertion in it includes: lifting the steel pipe pile to the installation position above the jacket conduit for pile insertion.

3. The method for driving inclined piles in sandy silt geological formations according to claim 2, Characterized in that, During the pile insertion process, the guide blocks of the jacket are used to ensure the inclination of the pile.

4. The method for driving inclined piles in sandy silt geological formations according to claim 3, Characterized in that, The guide blocks are pre-installed and polished and lengthened to 5 m.

5. The method for driving inclined piles in sandy silt geological formations according to claim 2, Characterized in that, The said step S 4 The pile driving therein includes: S 41 , insert the steel pipe pile into the jacket column; S 42 , hoist the vibratory hammer, keep the inclination of the hammer and the pile the same, clamp the vibratory hammer to the steel pipe pile, and then start the vibratory hammer; S 43 、After the steel pipe pile penetrates into the mud by one-third, replace the hydraulic hammer for hammering.

6. The method for driving inclined piles in sandy silt geological formations according to claim 5, Characterized in that, The said step S 4 The pile driving also includes: S 44 2. Start the hydraulic hammer to continue driving the pile. During the pile driving process, adjust the hammering energy according to the penetration speed of the pile into the mud; S 45 、 When the steel pipe pile penetrates into the mud and stops hammering when the lifting lug is about 1.5 m away from the top of the conduit, then cut off the lifting lug and polish it smoothly; S 46 , continue to hammer until the pre-designed depth is reached.

7. The method for driving inclined piles in sandy silt geological formations according to claim 6, Characterized in that, The said step S 44 In this step, the hydraulic hammer first hammers with 10% of its energy and then makes adjustments according to the penetration degree.

8. The method for driving inclined piles in sandy silt geological formations according to claim 5, Characterized in that, The said step S 43 is provided with a guide block on the bottom arm of the hammer cap of the hydraulic hammer.

9. The method for driving inclined piles in sandy silt geological formations according to claim 5, Characterized in that, The maximum stress during the pile driving process is less than or equal to 250 MPa, the maximum static stress of the pile hammer pressing the pile is less than or equal to 100 MPa, and the maximum combined stress acting on the pile body is less than or equal to 350 MPa.

10. The method for driving inclined piles in sandy silt geological formations according to claim 1, Characterized in that, The method for driving inclined piles in sandy silt geological formations further includes: vibration hammer pile driving analysis; Where: F 0 is the exciting force of the vibratory hammer; W 0 is the total weight of the vibratory hammer; P is the total weight of the steel pipe pile; ω is the angular velocity; K is the eccentric moment.

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