Construction method of offshore deep high-pressure jet mixing pile

Abstract

The application provides a construction method of offshore deep high-pressure jetting mixing pile, comprising the following steps: positioning and marking a preset opening position in a sea area to be constructed; drilling a hole at the preset opening position by a drilling machine until a drill rod of the drilling machine drills into a preset depth and forms a pile hole; injecting high-pressure air and water into the grouting channel in the drill rod; rotating the drill rod to jet high-pressure water flow around the drill rod through the grouting hole; jetting cement slurry around the drill rod through the grouting hole of the drill rod; rotating and lifting the drill rod until grouting is completed to form the mixing pile in the pile hole. The application drills a hole in a rock layer and a sediment layer in advance and then grouts, and simultaneously pre-cuts the rock layer and the sediment layer by high-pressure air and high-pressure water flow before grouting, so that the mud of the seabed itself and the cement slurry and soil are conveniently replaced, and the forming quality of the mixing pile when the deep high-pressure jetting mixing pile is constructed in a nearshore area is improved.

Description

Technical Field

[0001] This invention relates to the field of marine construction technology, and in particular to a construction method for deep-sea high-pressure jet grouting piles. Background Technology

[0002] Deep-Jet Mixing (DJM) construction technology is an effective method for improving the structural quality of deep soil and enhancing the bearing capacity of soft soil foundations. It was first applied in Japan in the 1970s.

[0003] In recent years, the methods used for foundation treatment have been continuously developed and innovated. When applied to near-shore construction, there are usually rock layers below the seabed. The hardness of the rock layers is much greater than that of the sedimentary layers, and the rock layers will inhibit the discharge of mud, which is not conducive to the replacement of cement slurry and mud on the seabed itself. Moreover, at greater depths, it is impossible to discharge the mud on the seabed itself. Therefore, the existing DJM construction technology has the problem of poor pile quality in near-shore construction. Summary of the Invention

[0004] The main objective of this invention is to provide a construction method for deep high-pressure jet grouting piles at sea, which aims to solve the problem of poor pile formation quality when existing deep high-pressure jet grouting piles are constructed in near-shore areas.

[0005] To achieve the above objectives, the present invention provides a construction method for deep-sea high-pressure jet grouting piles, comprising the following steps:

[0006] Locate and mark the pre-set opening positions in the sea area to be constructed;

[0007] The drilling rig drills a hole at the preset opening position until the drill rod of the drilling rig drills to the preset depth and forms a pile hole. The drill rod has a grouting channel inside and grouting holes are opened on the rod wall near the drill bit.

[0008] High-pressure air and water are injected into the grouting channel inside the drill pipe;

[0009] Rotate the drill rod to spray high-pressure water into the surrounding area of ​​the drill rod through the grouting hole;

[0010] Rotate and raise the drill rod until the drill bit of the drill rod rises to a preset height;

[0011] Rotate and lower the drill rod until the drill bit of the drill rod descends to the preset depth;

[0012] Cement grout and high-pressure air are injected into the drill pipe using a grouting machine;

[0013] Cement slurry is sprayed around the drill rod through the grouting hole;

[0014] Rotate and raise the drill rod until grouting is complete to form the mixing pile in the pile hole.

[0015] Preferably, the seabed of the area to be constructed includes sedimentary layers and rock layers; the step of drilling a hole at the preset opening position using a drilling rig until the drill rod of the drilling rig penetrates to the preset depth and forms a pile hole includes:

[0016] The drilling rig drills a hole at the preset opening position, while monitoring the drilling data at the drill bit. The drilling data includes the drill bit's lifting speed, rotation speed, pressure value at the grouting port, and air pressure.

[0017] When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock formation, and the drilling speed is slowed down. The preset range includes a preset drill bit lifting speed range, a preset drill bit rotation speed range, a preset grouting port pressure value range, and an air pressure value range.

[0018] When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer, and the drilling speed is slowed down until the preset depth is reached and a borehole is formed.

[0019] Preferably, the step of rotating and raising the drill rod until the drill bit of the drill rod rises to a preset height includes:

[0020] Monitor drilling data at the drill bit;

[0021] When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock stratum. The drill rod lifting speed is adjusted to 29cm / min~31cm / min, the water jet energy of the grouting hole is adjusted to 35MJ / m~36MJ / m, and the air pressure is adjusted to 11Bar~13Bar.

[0022] When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer. The drill rod lifting speed is adjusted to 89cm / min~91cm / min, the water jet energy of the grouting hole is adjusted to 10MJ / m~11MJ / m, and the air pressure is adjusted to 7Bar~9Bar, until the drill bit of the drill rod rises to the preset height.

[0023] Preferably,

[0024] The step of rotating and raising the drill rod until grouting is completed to form the mixing pile in the pile hole includes:

[0025] Monitor drilling data at the drill bit;

[0026] When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock stratum. The drill rod lifting speed is set to 8.2 cm / min to 8.6 cm / min, the cement slurry injection pressure is adjusted to 31 MPa, and the slurry injection energy of the injection hole is adjusted to 137 MJ / m to 139 MJ / m.

[0027] When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer. The drill rod lifting speed is adjusted to 7.8 cm / min to 8.0 cm / min, the cement slurry injection pressure is adjusted to 34 MPa, and the slurry injection energy of the grouting hole is adjusted to 168 MJ / m to 170 MJ / m until grouting is completed, so as to form the mixing pile in the pile hole.

[0028] Preferably, after the step of spraying cement slurry around the drill pipe, the method further includes:

[0029] Continuously spray cement slurry until the pressure at the grouting port of the drill rod reaches the second preset pressure value;

[0030] Rotate the drill rod for 4 to 6 minutes to form the bottom of the pile hole.

[0031] Preferably, the step of rotating and raising the drill rod until the grouting of the pile hole is completed includes:

[0032] Rotate and raise the drill rod while continuing to spray cement grout until the grouting port of the drill rod rises to a distance of 0.9m to 1.1m from the top of the pile hole;

[0033] Reduce the rising speed and stop rising every 0.5m when the drill rod rises. Rotate the drill rod in place for 4s to 6s and then continue rising until the cement slurry rises to the designed stopping surface. The grouting of the pile hole is then completed.

[0034] Preferably, the step of injecting cement grout and high-pressure air into the drill pipe using a grouting machine further includes:

[0035] Add cement powder to the cement weighing bucket and weigh the first preset weight of cement powder.

[0036] Seawater is pumped into a water weighing tank using a water pump, and the second preset weight of water is weighed.

[0037] The cement powder from the cement weighing bucket and the water from the water weighing bucket are added to a mixing bucket and stirred to obtain the cement slurry.

[0038] The cement slurry is pumped to the grouting machine using a slurry pumping device.

[0039] Preferably, the method further includes, before the step of locating and marking the preset opening position in the sea area to be constructed:

[0040] The geological environment of the seabed in the area to be constructed was surveyed, and the locations of surface gravel and metal debris were marked.

[0041] Clean up surface gravel and metal debris at the marked locations on the seabed;

[0042] The seabed in the area to be constructed is cleared of sea mud with an internal water level exceeding -3mPD to form a construction surface.

[0043] Preferably, after the step of cleaning up the marine mud with a water level exceeding -3mPD in the sea area to be constructed, the method further includes:

[0044] A protective layer of sand, 0.9m to 1.1m deep, is laid on the construction surface.

[0045] Preferably, after the step of laying a sand protective layer with a depth of 0.9m to 1.1m on the construction surface, the method further includes:

[0046] Four vertical support steel pipe piles are installed on the construction plane, and the four vertical support steel pipe piles form a rectangle;

[0047] Install the main beam between two adjacent vertical support steel pipe piles;

[0048] A platform is installed on the main beam to form a temporary support platform.

[0049] In the technical solution of this invention, a hole is first drilled at a predetermined opening position in the sea area to be constructed, penetrating the sedimentary layer and rock layer to form a pile hole. Then, a drill rod is inserted into the bottom of the pile hole, and high-pressure air and high-pressure water are sprayed into the surrounding sedimentary layer and rock layer through the drill rod to pre-cut the soil, cutting and destroying the soil surface to form holes of a certain size. During this process, the drill rod is slowly raised and rotated to a predetermined height so that the soil at a certain depth is pre-cut, which facilitates the thorough mixing of cement grout and soil during subsequent high-pressure grouting. After the drill rod rises to the predetermined height, high-pressure air and high-pressure water are sprayed and the drill rod sinks to the predetermined depth to pre-cut the soil again. Then, high-pressure air and cement grout are injected into the drill rod, cement grout is sprayed around the pile hole, and the drill rod is rotated and raised until the pile hole is completely grouted to form a mixing pile. This invention involves pre-drilling holes in rock and sedimentary layers before grouting, and pre-cutting the rock and sedimentary layers with high-pressure air and water before grouting. This facilitates the removal of mud, cement slurry, and soil from the seabed itself for replacement. Furthermore, the combined force application of high-pressure air and cement slurry water-air ensures uniform grouting even at depths, thus improving the forming quality of deep high-pressure jet grouting piles during nearshore construction. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0051] Figure 1 This is a flowchart illustrating a construction method for deep-sea high-pressure jet grouting piles according to an embodiment of the present invention.

[0052] Figure 2 This is a detailed flowchart of step S200 of a construction method for deep-sea high-pressure jet mixing piles according to an embodiment of the present invention.

[0053] Figure 3 This is a detailed flowchart of step S800 of a construction method for deep-sea high-pressure jet mixing piles according to an embodiment of the present invention.

[0054] Figure 4 This is a schematic diagram showing the position of the drilling rig relative to the seabed according to an embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram showing the position of the drilling rig and the seabed according to another embodiment of the present invention.

[0056] Explanation of icon numbers:

[0057] label name label name 10 seabed 20 drilling rig 11 rock strata 21 drill pipe 12 sedimentary layer 22 drill

[0058] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0059] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly.

[0061] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible to those skilled in the art. If a combination of technical solutions contradicts each other or cannot be implemented, such a combination should be considered non-existent and not within the scope of protection claimed by the present invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0064] This invention proposes a transport fixture for a vehicle chassis assembly.

[0065] Please combine Figure 1 , Figure 4 and Figure 5 The construction method of deep-sea high-pressure jet grouting piles in this embodiment includes the following steps:

[0066] S100: Locate and mark the pre-set opening positions in the sea area to be constructed;

[0067] The pre-set opening locations are calculated based on the area and topography of the sea area to be constructed. It should be noted that there are multiple pre-set opening locations, which are evenly distributed within the sea area to be constructed. Then, the pre-set opening locations are marked using GPS positioning to improve construction accuracy.

[0068] S200: Drilling is carried out by a drilling rig at a preset opening position until the drill rod of the drilling rig is drilled to a preset depth and a pile hole is formed. The drill rod has a grouting channel and grouting holes are opened on the rod wall near the drill bit.

[0069] During drilling, by detecting the drilling dynamic data at drill bit 22, it can be determined whether there are hard obstacles in the borehole. If the drilling effect is poor, the roller drill bit 22 or the hammer needs to be replaced to pre-treat the rock layer to form a hole, ensuring that there are no obvious obstacles in the pile hole.

[0070] S300: Inject high-pressure air and water into the grouting channel inside the drill pipe;

[0071] Drill rod 21 is connected to an air compressor and a high-pressure water pump to inject high-pressure water and high-pressure air into the grouting channel;

[0072] S400: Rotate the drill rod to spray high-pressure water into the surrounding area of ​​the drill rod through the grouting hole;

[0073] Rotate the drill rod 21 and simultaneously spray high-pressure water flow around the drill rod 21 through the grouting hole. Rotating the drill rod 21 can make the high-pressure water flow cut the soil layer around the drill rod 21 more evenly, and improve the replacement rate of subsequent cement slurry and soil mud.

[0074] S500: Rotate and raise the drill pipe until the drill bit rises to the preset height;

[0075] Rotating the drill rod 21 causes the soil at one end of the pile hole from the bottom to the preset height to be pre-cut. The part from the bottom of the pile hole to the preset height is a deep soil layer with high pressure and relatively viscous soil, which makes it difficult to discharge the mud itself and the cement slurry replacement rate is insufficient. Therefore, the soil layer is pre-cut by high-pressure air and high-pressure water flow in advance to facilitate the replacement of cement slurry and improve the forming quality of the mixing pile.

[0076] S600: Rotate and lower the drill pipe until the drill bit on the drill pipe descends to the preset depth;

[0077] During the descent, high-pressure air and high-pressure water jets continue to be sprayed to cut the soil again while preventing the mud in the soil from clogging the grouting port.

[0078] S700: Cement grout and high-pressure air are injected into the drill pipe using a grouting machine;

[0079] The drill pipe 21 is connected to the grouting machine and the air compressor, and high-pressure cement slurry and high-pressure air are injected into the drill pipe 21;

[0080] S800: Cement grout is sprayed around the drill rod through the grouting hole;

[0081] High-pressure water jets are sprayed around the drill rod 21 through the grouting hole. Rotating the drill rod 21 allows the cement grout to be evenly distributed around the pile, resulting in better pile quality.

[0082] S900: Rotate and raise the drill rod until grouting is complete to form a mixing pile at the pile hole.

[0083] In the technical solution of this invention, a hole is first drilled at a predetermined opening position in the sea area to be constructed, penetrating the sedimentary layer 12 and the rock layer 11 to form a pile hole. Then, a drill rod 21 is inserted into the bottom of the pile hole, and high-pressure air and high-pressure water are sprayed onto the surrounding sedimentary layer 12 and rock layer 11 through the drill rod 21 to pre-cut the soil, cutting and destroying the soil surface to form holes of a certain size. During this process, the drill rod 21 is slowly raised and rotated to a predetermined height so that the soil at a certain depth is pre-cut, which facilitates the full mixing of cement grout and soil during subsequent high-pressure grouting. After the drill rod 21 rises to the predetermined height, high-pressure air and high-pressure water are sprayed and it sinks to the predetermined depth to pre-cut the soil again. Then, high-pressure air and cement grout are injected into the drill rod 21, and cement grout is sprayed around the pile hole. The drill rod 21 is rotated and raised until the pile hole is completely grouted to form a mixing pile. This invention pre-drills holes in the rock layer 11 and sediment layer 12 before grouting, and pre-cuts the rock layer 11 and sediment layer 12 with high-pressure air and high-pressure water flow before grouting. This facilitates the removal of mud, cement slurry and soil from the seabed 10 itself for replacement. At the same time, the combined force of high-pressure air and cement slurry water-air ensures uniform grouting even at deep depths, thus improving the forming quality of deep high-pressure jet grouting piles during near-shore construction.

[0084] Please see Figure 2 In one embodiment, the seabed of the area to be constructed includes sedimentary layers and rock layers.

[0085] Step S200 includes:

[0086] S210: Drilling a hole at a preset opening position using a drilling rig, while simultaneously monitoring the drilling data at the drill bit, including the drill bit's lifting speed, rotation speed, pressure value at the grouting port, and air pressure;

[0087] Monitor the lifting speed, rotation speed, pressure value at the grouting port and air pressure at drill bit 22 to determine whether drill bit 22 is located in rock layer 11 or sedimentary layer 12;

[0088] S220: When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock formation, and the drilling speed is slowed down. The preset range includes the preset drill bit lifting speed range, the preset drill bit rotation speed range, the preset grouting port pressure value range, and the air pressure value range.

[0089] When drilling within rock stratum 11, the drilling speed needs to be slowed down to prevent drill rod breakage and improve construction safety.

[0090] S230: When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located in the sediment layer, and the drilling speed is slowed down until the preset depth is reached and a borehole is formed.

[0091] It should be noted that the construction area is adjacent to the old airport runway, and therefore contains a relatively thick rock layer. Therefore, by detecting the drilling data at the drill bit, it can be determined whether the drill bit is located in the rock layer, so as to adjust the drill rod lifting speed in time. When in the sedimentary layer 12, the drilling speed is increased to speed up the construction efficiency. The drill bit 22 penetrates the rock layer 11 and the sedimentary layer 12 to form a bored pile, which has a good effect on penetrating the hard layer and increases the construction depth.

[0092] Further, step S500 includes:

[0093] S510: Monitor drilling data at the drill bit;

[0094] Monitor the vibration data and pressure value at drill bit 22 to determine whether drill bit 22 is located in rock layer 11 or sedimentary layer 12;

[0095] S520: When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock formation. The drill rod lifting speed is adjusted to 29cm / min~31cm / min, the water jet energy of the grouting hole is adjusted to 35MJ / m~36MJ / m, and the air pressure is adjusted to 11Bar~13Bar.

[0096] S530: When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located in the sediment layer. The drill rod lifting speed is adjusted to 89cm / min~91cm / min, the water jet energy of the grouting hole is adjusted to 10MJ / m~11MJ / m, and the air pressure is adjusted to 7Bar~9Bar until the drill bit of the drill rod rises to the preset height.

[0097] Different strata have different external environments with varying density and pressure, resulting in different resistance to high-pressure water flow. Therefore, by adjusting the lifting speed of drill rod 21, the water jet energy of the grouting hole, and the air pressure, the size of the high-pressure water flow cutting can be made roughly the same under different strata conditions, which helps to improve the dimensional accuracy of subsequent jet grouting pile forming.

[0098] Step S900 includes:

[0099] S910: Monitor drilling data at the drill bit;

[0100] Monitor the vibration data and pressure value at drill bit 22 to determine whether drill bit 22 is located in rock layer 11 or sedimentary layer 12;

[0101] S920: When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock stratum, the drill rod lifting speed is set to 8.2cm / min~8.6cm / min, the cement slurry injection pressure is adjusted to 31MPa, and the slurry injection energy of the injection hole is adjusted to 137MJ / m~139MJ / m;

[0102] S930: When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer. The drill rod lifting speed is adjusted to 7.8cm / min~8.0cm / min, the cement slurry injection pressure is adjusted to 34MPa, and the slurry injection energy of the grouting hole is adjusted to 168MJ / m~170MJ / m until grouting is completed, so as to form the mixing pile in the pile hole.

[0103] In different geological formations, the viscosity and pressure of the external environment vary, resulting in different resistance to high-pressure cement grout. Therefore, by adjusting the lifting speed of the drill rod 21, the injection pressure of the cement grout, and the air pressure, the injection range of the high-pressure cement grout can be made approximately the same in different geological environments, which helps to improve the dimensional accuracy of the jet grouting pile.

[0104] Please see Figure 3 Furthermore, step S800 also includes:

[0105] S810: Continuously spray cement grout until the pressure at the grouting port of the drill pipe reaches the second preset pressure value;

[0106] When the pressure value at the grouting port reaches the second preset pressure value, the range of grout spraying from the port reaches the design radius of the jet grouting pile, and the formed jet grouting pile has uniform size.

[0107] S820: Rotate the drill rod for 4 to 6 minutes to form the bottom of the pile hole.

[0108] Since the pile bottom is the deepest point, the cement grout is not easy to replace the soil itself, and the pile bottom has high quality requirements. Therefore, after the rotary drill rod 21 starts to spray cement grout, it continues for 4 to 6 minutes until grout appears at the hole opening, which proves that the replacement of grout and soil has started smoothly, forming the pile bottom and improving the forming quality of the pile bottom.

[0109] In one embodiment, step S900 includes:

[0110] S910: Rotate the drill rod upwards while continuing to spray cement grout until the grouting port of the drill rod rises to a distance of 0.9m to 1.1m from the top of the pile hole;

[0111] Continue to rotate and raise the drill rod 21 until it rises to a position close to the top of the pile. Preferably, start from 1m below the top of the pile. At this point, it is close to the top of the pile and is in the final stage. The rising speed needs to be adjusted.

[0112] S920: Reduce the rising speed and stop rising every 0.5m when the drill rod is raised. Rotate and spray grout in place for 4s to 6s and then continue rising until the cement grout rises to the designed stopping surface, and the grouting of the pile hole is completed.

[0113] By reducing the rising speed and increasing the replacement rate of cement grout with the soil layer at the top of the pile, and stopping the rise every 0.5m, rotating and spraying grout in place for 4s to 6s before continuing to rise, the replacement rate of cement grout with the surrounding soil layer is further guaranteed, thereby improving the forming quality of the pile top.

[0114] In one embodiment, the method further includes the following steps before step S700:

[0115] S690: Add cement powder to the cement weighing bucket and weigh the first preset weight of cement powder;

[0116] The cement powder is ordinary Portland cement, conforming to BS EN 197-1:2000 standard, and the cement strength grade is 52.5N;

[0117] S691: Seawater is pumped into a water weighing tank by a water pump and weighed to a second preset weight;

[0118] The ratio of the second preset weight to the first preset weight is 0.9 / 1, which means the water-cement ratio is 0.9 / 1.

[0119] S692: Add cement powder from the cement weighing bucket and water from the water weighing bucket to the mixing bucket and mix to obtain cement slurry.

[0120] S693: Cement slurry is pumped to the grouting machine via a grouting device.

[0121] This project requires the construction of DJM and grouting at sea. Due to the limited construction space, a construction scheme of remote grouting and pumping at sea is adopted. Since the overall water consumption is huge and fresh water is difficult to supply, seawater is used instead of fresh water to ensure the cement water supply while saving costs. Since the mixer is remotely grouting and far from the drilling rig, the cement slurry is pumped to the drilling rig through a pumping device.

[0122] In one embodiment, the method further includes the following steps before step S100:

[0123] S90: Survey the seabed geological environment of the area to be constructed and mark the locations of surface gravel and metal debris;

[0124] The geological environment of the seabed in the area to be constructed was surveyed using an underwater 3D imaging system, a 3D image report of the seabed depth was obtained, and obstacles such as surface gravel and metal debris that would affect pile driving were cleared.

[0125] S91: Clean up surface gravel and metal debris at marked locations on the seabed;

[0126] S92: Clear marine mud with an inner water level exceeding -3 mPD from the seabed in the area to be constructed, creating a construction surface. Remove marine mud with an inner water level exceeding -3 mPD to avoid obstructing the navigation of construction vessels.

[0127] To facilitate the marine engineering project and minimize its impact on the marine environment, the project requires the seabed in the construction area to be leveled based on the preliminary seabed environmental survey report. This will prevent debris and mud from affecting the deployment of subsequent construction equipment and thus the construction progress.

[0128] In one embodiment, step S92 is followed by:

[0129] S93: Lay a protective sand layer 0.9m to 1.1m deep on the construction surface.

[0130] A 1-meter-deep sand layer was laid on the seabed in the construction area to prevent cement slurry from spreading in the seawater during DJM drilling and grouting, and to reduce the risk of vibration damage to the existing structure during pile driving.

[0131] In one embodiment, step S93 is followed by:

[0132] S94: Install four vertical support steel pipe piles on the construction plane, forming a rectangle with the four vertical support steel pipe piles;

[0133] S95: Install the main beam between two adjacent vertical support steel pipe piles;

[0134] S96: Install a platform on the main beam to form a temporary support platform. Since the drilling locations are all at sea, in order to improve construction efficiency, it is necessary to build a support platform near the sea so that the drilling rig can move on the support platform without having to use a construction vessel to anchor on the sea surface. This can improve both construction efficiency and construction accuracy.

[0135] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A construction method for deep-sea high-pressure jet grouting piles, characterized in that, The seabed in the area to be developed includes sedimentary layers and rock strata; the following steps are included: Locate and mark the pre-set opening positions in the sea area to be constructed; The drilling rig drills a hole at the preset opening position until the drill rod of the drilling rig drills to the preset depth and forms a pile hole. The drill rod has a grouting channel inside and grouting holes are opened on the rod wall near the drill bit. High-pressure air and water are injected into the grouting channel inside the drill pipe; Rotate the drill rod to spray high-pressure water into the surrounding area of ​​the drill rod through the grouting hole; Rotate and raise the drill rod until the drill bit of the drill rod rises to a preset height; Rotate and lower the drill rod until the drill bit of the drill rod descends to the preset depth; Cement grout and high-pressure air are injected into the drill pipe using a grouting machine; Cement slurry is sprayed around the drill rod through the grouting hole; Rotate and raise the drill rod until grouting is complete to form the mixing pile in the pile hole; The step of rotating and raising the drill rod until the drill bit of the drill rod rises to a preset height includes: Monitor drilling data at the drill bit; When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located within the rock stratum. The drill rod lifting speed is adjusted to 29cm / min~31cm / min, the water jet energy of the grouting hole is adjusted to 35MJ / m~36MJ / m, and the air pressure is adjusted to 11Bar~13Bar. The preset range includes the preset drill bit lifting speed range, the preset drill bit rotation speed range, the preset grouting port pressure value range, and the air pressure value range. When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer. The drill rod lifting speed is adjusted to 89cm / min~91cm / min, the water jet energy of the grouting hole is adjusted to 10MJ / m~11MJ / m, and the air pressure is adjusted to 7Bar~9Bar until the drill bit of the drill rod rises to the preset height. The step of rotating and raising the drill rod until grouting is completed to form the mixing pile in the pile hole includes: Monitor drilling data at the drill bit; When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located in the rock stratum. The drill rod lifting speed is set to 8.2cm / min~8.6cm / min, the cement slurry injection pressure is adjusted to 31MPa, and the slurry injection energy of the injection hole is adjusted to 137MJ / m~139MJ / m. When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer. The drill rod lifting speed is adjusted to 7.8 cm / min to 8.0 cm / min, the cement slurry injection pressure is adjusted to 34 MPa, and the slurry injection energy of the grouting hole is adjusted to 168 MJ / m to 170 MJ / m until grouting is completed, so as to form the mixing pile in the pile hole.

2. The construction method for deep-sea high-pressure jet grouting piles as described in claim 1, characterized in that, The step of drilling a hole at the preset opening position using a drilling rig until the drill rod of the drilling rig reaches the preset depth and forms a pile hole includes: The drilling rig drills a hole at the preset opening position, while monitoring the drilling data at the drill bit. The drilling data includes the drill bit's lifting speed, rotation speed, pressure value at the grouting port, and air pressure. When the drilling data at the drill bit exceeds the preset range, it is determined that the drill bit is located within the rock stratum, and the drilling speed is slowed down. When the drilling data at the drill bit is within the preset range, it is determined that the drill bit is located within the sediment layer, and the drilling speed is slowed down until the preset depth is reached and a borehole is formed.

3. The construction method for deep-sea high-pressure jet grouting piles as described in claim 1, characterized in that, The step of spraying cement slurry around the drill pipe through the drill pipe also includes: Continuously spray cement slurry until the pressure at the grouting port of the drill rod reaches the second preset pressure value; Rotate the drill rod for 4 to 6 minutes to form the bottom of the pile hole.

4. The construction method for deep-sea high-pressure jet grouting piles as described in claim 1, characterized in that, The step of rotating and raising the drill rod until the grouting of the pile hole is completed includes: Rotate and raise the drill rod while continuing to spray cement grout until the grouting port of the drill rod rises to a distance of 0.9m to 1.1m from the top of the pile hole; Reduce the rising speed and stop rising every 0.5m when the drill rod rises. Rotate the drill rod in place for 4s to 6s and then continue rising until the cement slurry rises to the designed stopping surface. The grouting of the pile hole is then completed.

5. The construction method for deep-sea high-pressure jet grouting piles as described in any one of claims 1 to 4, characterized in that, Prior to the step of injecting cement slurry and high-pressure air into the drill pipe using a grouting machine, the following also includes: Add cement powder to the cement weighing bucket and weigh the first preset weight of cement powder. Seawater is pumped into a water weighing tank using a water pump, and the second preset weight of water is weighed. The cement powder from the cement weighing bucket and the water from the water weighing bucket are added to a mixing bucket and stirred to obtain the cement slurry. The cement slurry is pumped to the grouting machine using a slurry pumping device.

6. The construction method for deep-sea high-pressure jet grouting piles as described in any one of claims 1 to 4, characterized in that, The procedure before locating and marking the preset opening position in the sea area to be constructed includes: The geological environment of the seabed in the area to be constructed was surveyed, and the locations of surface gravel and metal debris were marked. Clean up surface gravel and metal debris at the marked locations on the seabed; The seabed in the area to be constructed is cleared of sea mud with an internal water level exceeding -3mPD to form a construction surface.

7. The construction method for deep-sea high-pressure jet grouting piles as described in claim 6, characterized in that, The step of cleaning up the marine mud with a water level exceeding -3 mPD in the sea area to be constructed also includes: A protective layer of sand, 0.9m to 1.1m deep, is laid on the construction surface.

8. The construction method for deep-sea high-pressure jet grouting piles as described in claim 7, characterized in that, The step of laying a 0.9m to 1.1m deep sand protective layer on the construction surface also includes: Four vertical support steel pipe piles are installed on the construction plane, and the four vertical support steel pipe piles form a rectangle; Install the main beam between two adjacent vertical support steel pipe piles; A platform is installed on the main beam to form a temporary support platform.

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