A single-point multi-pile double high-pressure jet grouting system and method

Abstract

The present application discloses a single-point multi-pile double high-pressure jet grouting system and method. The system includes a drill bit, a drill pipe, a grouting pipe, a horizontal directional drill, and a grouting pump. The drill bit is installed at the front end of the drill pipe; one end of the grouting pipe is connected to the tail end of the drill pipe, and the other end is fixedly arranged on the horizontal directional drill; the grouting pump is connected to the grouting pipe; a high-pressure cement slurry channel and a high-pressure water-air channel are provided inside the drill pipe; the drill bit includes a main body rod portion fixedly connected to the drill pipe and a guide plate connected to the main body rod portion. The guide plate includes a plurality of roller cutters and spikes for rock breaking arranged on its periphery. A vibration motor for driving the roller cutters and spikes to vibrate is provided at a position of the main body rod portion close to the guide plate. The beneficial effects of the present application are as follows: A new type of drill bit is redesigned, enabling it to achieve trenchless drilling along a predetermined design trajectory and simultaneously complete high-pressure jet grouting work; during the grouting work, it realizes the functions of light disturbance, low pollution, and real-time monitoring, and finally forms a high-quality grouting reinforcement body.

Description

Technical Field

[0001] This application relates to the field of civil engineering technology, and particularly to an integrated trenchless low-disturbance single-point multi-pile double high-pressure jet grouting system and method.

Background Art

[0002] Due to the current shortage of urban space on the ground, large-scale development of underground urban space is the future trend. Nowadays, urban underground pipe networks and tunnel networks are gradually becoming denser. Underground pipeline construction and shield construction cause the soil layer to loosen, which in turn leads to serious accidents such as the collapse and cracking of superstructures, tunnels, and road surfaces. Therefore, it is necessary to reinforce designated areas in the complex underground space of the city to reduce the disturbance of subsequent underground construction to existing basements, tunnels, and urban main buildings. Thus, a good foundation is laid for deeper underground space development in the future.

[0003] Traditional ground pre-grouting and tracking grouting generally adopt the form of vertical holes on the ground. Affected by the location of surface buildings and underground pipelines, it is often difficult to arrange holes, with construction blind spots. At the same time, construction occupies the ground road, bringing inconvenience to traffic and the normal life of surrounding residents; there are problems such as narrow construction space, limited reinforcement range, and cross-operation being not conducive to project progress control in underground shield synchronous grouting and advanced grouting; if horizontal grouting is to be carried out at the bottom of the tunnel, due to the complexity of the underground pipe network, if horizontal grouting is to be carried out in a certain area below the ground, only vertical shafts can be excavated on the ground and then horizontal grouting can be carried out. This construction method is difficult, costly, requires high construction sites, and may affect the surrounding environment and traffic.

[0004] Current grouting technologies mainly include low-pressure permeation grouting, medium-pressure compaction grouting, relatively high-pressure fracturing grouting, and high-pressure jet grouting. Permeation grouting causes less disturbance to the soil, but its grouting reinforcement quality is not high and uneven; both compaction grouting and fracturing grouting cause greater disturbance to the soil, and the reinforcement quality is higher than that of permeation grouting, but the reinforcement is still uneven; high-pressure jet grouting uses high pressure to cut and partially or completely remove the soil, and the slurry is evenly stirred with the soil within the cutting range to form a high-strength structure, and the reinforcement uniformity is the best.

Summary of the Invention

[0005] This application discloses a single-point multi-pile double high-pressure jet grouting system and method, which can solve the problems that grouting is hindered by surface buildings and underground pipelines and the problem of high-quality grouting reinforcement, and thus can effectively solve at least one technical problem involved in the background art.

[0006] To achieve the above object, the technical solution of this application is as follows:

[0007] A single-point multi-pile double high-pressure jet grouting system includes a drill bit, a drill pipe, a grouting pipe, a horizontal directional drill, and a grouting pump. The drill bit is installed at the front end of the drill pipe. One end of the grouting pipe is connected to the tail end of the drill pipe, and the other end is fixed to the horizontal directional drill. The grouting pump is connected to the grouting pipe. A high-pressure cement slurry channel and a high-pressure water-air channel are provided inside the drill pipe, and a slurry suction pipe is fixed on the outer surface of the drill pipe. The drill bit includes a main body rod portion fixedly connected to the drill pipe and a guide plate connected to the main body rod portion. The main body rod portion is provided with a high-pressure water-air nozzle communicating with the high-pressure water-air channel, a high-pressure nozzle communicating with the high-pressure cement slurry channel, and a low-pressure nozzle communicating with the high-pressure water-air channel. The guide plate includes a plurality of rolling blades and spikes for rock breaking provided on its periphery. A vibration motor for driving the rolling blades and spikes to vibrate is provided at a position of the main body rod portion close to the guide plate.

[0008] Optionally, it further includes a mixing barrel connected to the grouting pump.

[0009] Optionally, the number of the slurry suction pipes is multiple, and the multiple slurry suction pipes are uniformly arranged along the circumferential direction of the drill pipe.

[0010] Optionally, the slurry suction pipe is fixed to the outer surface of the drill pipe through a slurry suction pipe fixator.

[0011] Optionally, a ground pressure detection hole is further provided on the main body rod portion.

[0012] Optionally, the rolling blades and the spikes are arranged alternately.

[0013] The present application also discloses an integrated trenchless low-disturbance single-point multi-pile double high-pressure jet grouting method based on the above system, including the following steps:

[0014] Step 1: In the working pit at the drilling point, drill the drill bit along a predetermined trajectory to the starting point of the grouting area.

[0015] Step 2: Adjust the drilling direction, drill towards the first grouting area, and stop at the grouting end point.

[0016] Step 3: Pull back the drill pipe, and the drill pipe drives the drill bit to rotate for high-pressure rotary jet grouting. At the same time, the ground pressure detection hole monitors the slurry pressure in the hole in real time. If the slurry pressure is greater than the original ground stress here, execute Step 4.

[0017] Step 4: Start the slurry suction pipe to work, suck out the slurry, and reduce the slurry pressure until it is reduced to the original ground stress.

[0018] Step 5: After the drill pipe is dragged back to the starting point of the grouting area, adjust the drilling direction, drill towards the second grouting area, and stop at the grouting end point, then execute Steps 3 and 4;

[0019] Step 6: After the grouting work in the grouting area is completed, drag the drill pipe and the drill bit back to the ground until the drill bit disengages from the soil mass.

[0020] Optionally, during the drilling process, cut the soil mass through the slurry ejected from the guide plate and the low-pressure nozzles at the front end of the drill bit; when encountering a hard formation or a formation with underground obstacles, use vibration to break the rock and soil mass with the rolling blades and spurs on the guide plate to complete the drilling.

[0021] Optionally, before Step 1, it further includes:

[0022] On-site investigation to determine the topography, underground tunnels, pipelines, and above-ground structures at the construction site;

[0023] Trajectory design, design the predetermined trajectory during drilling according to the results of the on-site investigation and the expected grouting design requirements;

[0024] Inspection of construction equipment, detect whether each construction equipment is normal;

[0025] Preparation of the working pit at the entry point, excavate the working pit at the entry point.

[0026] The beneficial effects of this application are as follows:

[0027] 1. The path during grouting drilling can be arbitrarily formulated as required. In this way, the construction can bypass urban dense areas and existing tunnels, has sufficient working space, does not occupy roads, and the construction process does not affect the lives of residents, and can be applied to scenarios with complex underground tunnels and pipe networks;

[0028] 2. Adopt trenchless drilling. When drilling, it is not necessary to excavate the soil mass, the engineering quantity is small, the cost is reduced, and low carbon is realized;

[0029] 3. Integrate drilling along the predetermined trajectory and high-pressure jet grouting. Only one drill is required. After reaching the grouting point, the grouting work can be started, which greatly reduces the construction time and construction difficulty;

[0030] 4. The single-point multi-pile construction method is adopted. When drilling along the predetermined trajectory, by controlling the position and direction of the inflection point, it is possible to use the same entry section to construct piles in different drilling sections. Within the regional pile section, there is no need to frequently change the position of the drilling rig. With the help of the same entry section, the frequent drilling construction can be reduced. The single-point multi-pile construction occupies a small area and causes less damage to the environment. Drilling and grouting are carried out on one platform, which greatly simplifies the drilling operation along the predetermined trajectory, improves the equipment utilization rate, reduces the cost of drilling fluid, and effectively shortens the drilling time. The pile formed by the grouting work of only spraying high-pressure cement slurry has a small diameter. Using the single-point multi-pile construction, a large-diameter combined pile body can be formed, which can meet the requirements of a larger diameter of the reinforced area in the underground space.

[0031] 5. By using a horizontal directional drilling rig, an entry angle of 0 - 90° can be achieved. The larger the entry angle, the less drill pipe is consumed by the path, and it is more capable of drilling into the middle of surface buildings.

[0032] 6. During the grouting process, through the slurry suction pipe, the stress in the underground grouting hole can be nearly in the original state, thereby realizing micro-disturbance to the surrounding soil environment, which will protect the surrounding underground tunnels, pipelines, and above-ground structures that are extremely sensitive to settlement.

[0033] 7. Install multiple roller blades and spikes on the guide plate at the front end of the drill bit. When encountering hard strata or strata with underground obstacles during the drilling process, the roller blades and spikes can break the rock and soil mass through high-frequency vibration to complete smooth drilling. It can adapt to a wider range of strata.

Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings, where:

[0035] Figure 1 It is a non-excavation grouting schematic diagram of a single-point multi-pile double high-pressure jet grouting system provided by an embodiment of the present application;

[0036] Figure 2 It is an assembly structure schematic diagram of a drill pipe and a drill bit provided by an embodiment of the present application;

[0037] Figure 3 It is a structure schematic diagram of a drilling rig lifting platform of a horizontal directional drilling rig provided by an embodiment of the present application;

[0038] Figure 4 It is a drilling schematic diagram under different entry angle conditions provided by an embodiment of the present application;

[0039] Figure 5 Schematic diagram of the cross-sectional structure of the drill pipe provided by the embodiment of the present application;

[0040] Figure 6 Construction schematic diagram of soil micro-disturbance provided by the embodiment of the present application;

[0041] Figure 7 Schematic diagram of the structure of the drill bit provided by the embodiment of the present application;

[0042] Figure 8 Schematic diagram of the cross-sectional structure after the slurry suction pipe and the drill pipe are assembled provided by the embodiment of the present application;

[0043] Figure 9 Simple construction diagram of single-point multi-pile provided by the embodiment of the present application;

[0044] Figure 10 Schematic diagram of the structure of the composite pile provided by the embodiment of the present application.

Specific embodiments

[0045] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0046] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0047] In addition, the descriptions such as "first" and "second" in the present application are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0048] In this application, unless otherwise clearly specified or limited, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0049] In addition, the technical solutions between various embodiments of this application can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0050] Please refer to Figure 1 and 2 As shown, this application provides a single-point multi-pile double high-pressure jet grouting system, including a drill bit 1, a drill pipe 2, a grouting pipe 3, a horizontal directional drill 4, and a grouting pump 5. The drill bit 1 is installed at the front end of the drill pipe 2. The drill bit 1 includes a main body rod portion 11 fixedly connected to the drill pipe 2 and a guide plate 12 connected to the main body rod portion 11.

[0051] One end of the grouting pipe 3 is connected to the tail end of the drill pipe 2, and the other end is fixedly arranged on the horizontal directional drill 4.

[0052] Combined with Figure 3 As shown, the horizontal directional drill 4 is provided with a drill rig lifting platform 41 and a hydraulic driver 42 for driving the drill rig lifting platform 41 to rotate. In this way, the horizontal directional drill 4 can achieve a drilling angle of 0-90°. The larger the drilling angle, the less drill pipe is consumed by the path, and it can penetrate more easily among surface buildings. Specifically, refer to Figure 4 As shown. If there are buildings around the drilling point, a large drilling angle can better meet the construction requirements, while a small drilling angle requires finding another open space for construction operations. When the drilling angle is 30°, construction is affected by the buildings and cannot be carried out, and construction can only be carried out in a farther place; when the drilling angle is 45°, construction can be carried out in the open space between two buildings.

[0053] The grouting pump 5 is connected to the grouting pipe 3. In this way, the grouting pump 5 can input the cement slurry into the grouting pipe 3 to form high-pressure cement slurry.

[0054] Combined with Figure 5As shown, a high-pressure cement slurry channel 21 and a high-pressure water-air channel 22 are provided inside the drill pipe 2. A high-pressure water-air nozzle 111 communicating with the high-pressure water-air channel 22, a high-pressure nozzle 112 communicating with the high-pressure cement slurry channel 21, and a low-pressure nozzle 113 communicating with the high-pressure water-air channel 22 are provided on the main rod part 11. In this way, high-pressure water or high-pressure air can be ejected through the high-pressure water-air nozzle 111, high-pressure cement slurry can be ejected through the high-pressure nozzle 112, and higher-pressure or lower-pressure water can be ejected through the low-pressure nozzle 113.

[0055] A ground pressure detection hole 13 is also provided on the main rod part 11.

[0056] A slurry suction pipe 6 is fixedly provided on the outer surface of the drill pipe 2. The number of the slurry suction pipes 6 is multiple, and the multiple slurry suction pipes 6 are uniformly arranged along the circumferential direction of the drill pipe 2.

[0057] In some embodiments, the slurry suction pipe 6 is fixed to the outer surface of the drill pipe 2 through a slurry suction pipe fixer 7.

[0058] Combined with Figure 6 As shown, by providing the slurry suction pipe 6, during grouting construction, micro-disturbance of the soil body can be achieved. Specifically, when the stress P monitored by the ground pressure detection hole 13 > γH p , the pressure inside the underground hole is reduced through the slurry suction pipe 6; when the stress P monitored by the ground pressure detection hole 13 < γH p , the pressure inside the underground hole is increased through a grout blocking ring (not shown). P = γH is achieved through the slurry suction pipe 6 and the grout blocking ring p .

[0059] By regulating the slurry suction pipe 6, the slurry pressure inside the underground hole is made equal to the original self-weight stress of the soil body at this position, that is, the stress P monitored by the ground pressure detection hole 13 = γH p , thereby achieving micro-disturbance of the surrounding soil body.

[0060] When the stress P inside the hole monitored by the ground pressure detection hole 13 > γH p , at this time, the slurry suction pipe 6 is controlled by a slurry suction pump to perform slurry suction work, thereby reducing the slurry pressure inside the hole. When the pressure P drops to equal γH p , the slurry suction stops. At this time, because the stress P monitored by the ground pressure detection hole 13 = γH p , the stress condition of the soil body around the pile body 10 is almost the same as before construction, thereby achieving micro-disturbance of the surrounding soil body. It is of great significance for grouting work with strict requirements for ground settlement, such as subway tunnels that are extremely sensitive to ground settlement around.

[0061] Combined with again Figure 7As shown, the guiding plate 12 includes a plurality of roller cutters 121 and spikes 122 for rock breaking provided on its periphery. A vibration motor (not shown) for driving the roller cutters 121 and spikes 122 to vibrate is provided at a position of the main body rod portion 11 close to the guiding plate 12. The vibration motor provides vibration to drive the roller cutters 121 and spikes 122 to vibrate.

[0062] In some embodiments, the roller cutters 121 and spikes 122 are arranged alternately.

[0063] By providing the roller cutters 121 and spikes 122, when encountering a hard formation or a formation with underground obstacles during the drilling process, the drill pipe 2 drives the drill bit 1 to rotate to generate mechanical pressure friction on the rock mass, and then the high-frequency vibration of the vibration motor causes the roller cutters 121 and spikes 122 to break the rock and soil mass, completing a smooth drilling. The high-frequency vibration of the vibration motor can be adjusted according to the situation of the borehole.

[0064] It should be noted that by arranging the roller cutters 121 between the spikes 122, the roller cutters 121 will generate mechanical pressure friction on the surrounding rock and soil mass under the action of micro-vibration. The gap part in the middle of the roller cutters 121 will hold the soil mass, and the mechanical pressure under vibration can better break the rock and soil mass. Therefore, by using the roller cutters 121 and spikes 122 simultaneously, the rock breaking effect can be significantly improved.

[0065] To further improve the rock breaking efficiency, at least two rows of the roller cutters 121 and spikes 122 are arranged along the advancing direction of the drill bit 1.

[0066] In addition, when the roller cutters 121 and spikes 122 are breaking rocks, the high-pressure water-air nozzle 111 ejects high-pressure gas, and the gas forms ultra-high pressure in a local space to assist in rock breaking. At the same time, the high-pressure water is continuously ejected through the low-pressure nozzle 113 to carry away the broken rock debris. When the broken rock debris blocks the front end, it will greatly hinder the further breaking of the rock mass. The high-pressure water carrying away the rock debris can greatly improve the rock breaking effect. Through the cooperation of the roller cutters 121 and spikes 122, the high-pressure water-air nozzle 111 and the low-pressure nozzle 113, under the multiple actions of mechanical friction, vibration and air pressure splitting, the broken rock debris of the rock mass is carried away by the water flow, significantly improving the rock breaking effect.

[0067] In some embodiments, the vibration motor is a micro high-frequency vibration motor.

[0068] The system further includes a mixing barrel 8 connected to the grouting pump 5. The grouting pump 5 injects the cement slurry in the mixing barrel 8 into the grouting pipe 3.

[0069] In order to make the connection between the drill bit 1 and the drill pipe 2 more secure, the drill bit 1 and the drill pipe 2 are fixedly connected through a fixing ring 9. In this way, not only is the fixation firm, but also disassembly and assembly are convenient.

[0070] In some embodiments, as Figure 8 shown, the slurry suction pipe 6 is arranged on the drill pipe 2 through the slurry suction pipe fixator 7 at the central part of each drill pipe 2.

[0071] The present application also discloses an integrated trenchless low-disturbance single-point multi-pile double high-pressure jet grouting method, including the following steps:

[0072] Step 1: As combined with Figure 9 shown, in the working pit at the drilling point, the drill bit is drilled along a predetermined trajectory to the starting point O of the grouting area.

[0073] Actually, before Step 1, it also includes:

[0074] On-site investigation to determine the topography, underground tunnels, pipelines and above-ground structures at the construction site, so as to determine the construction site and the drilling point, etc.;

[0075] Trajectory design, according to the results of on-site investigation and the expected grouting design requirements, design the predetermined trajectory during drilling;

[0076] Inspection of construction equipment to detect whether each construction equipment is normal;

[0077] Preparation of the working pit at the drilling point, dig out a working pit of 2.0 * 1.5 * 2.0 meters at the drilling point.

[0078] Step 2: Adjust the drilling direction, drill towards the first grouting area A, and stop at the grouting end point;

[0079] It should be noted that during the drilling process of the drill bit 1, the soil is cut by the water ejected from the guide plate 12 and the low-pressure nozzle 113 at the front end of the drill bit 1. When encountering a hard formation or a formation with underground obstacles, the high-frequency vibration generated by the vibration motor can be used to make the rolling cutter blades 121 and the spurs 122 break the rock and soil mass to complete smooth drilling.

[0080] Step 3: Pull back the drill pipe 2, and the drill pipe 2 drives the drill bit 1 to rotate for high-pressure jet grouting. At the same time, the ground pressure detection hole 13 monitors the slurry pressure in the hole in real time. If the slurry pressure is greater than the original ground stress here, then execute Step 4;

[0081] It should be noted that the horizontal directional drill 4 provides power, and the drill pipe 2 drives the drill bit 1 to rotate and pull back. While rotating and pulling back, slurry is sprayed to form a grouting solidified body. Among them, high-pressure slurry and high-pressure air are injected into the drill pipe 2 from different channels at the drill rig. The hollow part of the drill pipe 2 serves as the channels for slurry and high-pressure air. After the slurry reaches the drill bit 1, it is sprayed out from the high-pressure nozzle 112. For high-pressure air, when high-pressure air is sprayed, that is, high-pressure air wraps around the high-pressure slurry and sprays, because spraying slurry upward will generate an airbag. Therefore, the grouting solidified body is designed to form a semi-circle (sector) by spraying slurry at 0°-180° downward; when high-pressure air is not sprayed, at this time it is single-tube high-pressure jet grouting, and any shape between 0°-360° can be formed; when high-pressure air is not sprayed, according to experience, the pile diameter of the pile formed by grouting is about 40% loss.

[0082] Step Four: Start the slurry suction pipe 6 to work, suck out the slurry, and reduce the slurry pressure until it is reduced to the original in-situ stress.

[0083] It should be noted that during the grouting operation, the in-situ pressure detection hole 13 at the drill pipe 2 monitors the slurry pressure in the hole in real time. If the slurry pressure is greater than the original in-situ stress here, then start the slurry suction pipe 6 to work, suck out the slurry, reduce the slurry pressure in the hole, and restore the pressure to the original state. By stabilizing the pressure in the underground hole, micro-disturbance of the surrounding soil environment is achieved.

[0084] Step Five: After the drill pipe 2 is pulled back to the starting point O of the grouting area, adjust the drilling direction, drill towards the second grouting area B, and stop at the grouting end point, then execute Step Three and Four.

[0085] It should be noted that in combination with Figure 9 and 10 shown, in the manner of referring to Step Five, after the grouting work of the second grouting area B is completed, grouting can also be continued for the third grouting area C, the fourth grouting area D, the fifth grouting area E, the sixth grouting area F, and the seventh grouting area G. After all the grouting work is completed, the composite pile is formed.

[0086] Generally speaking, this application adopts the single-point multi-pile construction method, which can, when the drill bit 1 drills along the predetermined trajectory, by controlling the inflection point position and direction, realize the construction of forming piles in different drilling sections using the same entry section. As Figure 8 shown. Its main advantages are as follows:

[0087] 1. In the regional pile section, there is no need to frequently change the position of the drill rig. By using the same entry section, frequent drilling construction can be reduced. The single-point multi-pile construction occupies a small area and causes less damage to the environment. Drilling and grouting are carried out on one platform. It greatly simplifies the drilling operation along the predetermined trajectory, improves the equipment utilization rate, reduces the drilling fluid cost, and effectively shortens the drilling time.

[0088] 2. The diameter of the pile formed by the grouting work that only injects high-pressure cement slurry is relatively small. By using single-point multi-pile construction, a large-diameter pile body 10 can be formed, as Figure 10 shown.

[0089] Step Six: After the grouting work in the area to be grouted is completed, pull back the drill pipe and the drill bit to the ground until the drill bit is separated from the soil mass, and then clean the drill bit 1 and the drill pipe 2.

[0090] The beneficial effects of this application are as follows:

[0091] 1. The path during grouting drilling can be arbitrarily determined according to requirements. In this way, the construction can bypass urban dense areas and existing tunnels, has sufficient working space, does not occupy roads, and does not affect the lives of residents during the construction process, and can be applied to scenarios with complex underground tunnels and pipe networks;

[0092] 2. Non-excavation drilling is adopted, and the soil mass does not need to be excavated during drilling. The engineering quantity is small, the cost is reduced, and low carbon is realized;

[0093] 3. The integration of drilling along a predetermined trajectory and high-pressure jet grouting only requires one downhole operation. After reaching the grouting point, the grouting work can be started, which greatly reduces the construction time and construction difficulty;

[0094] 4. Single-point multi-pile construction is adopted. When drilling along a predetermined trajectory, by controlling the position and direction of the inflection point, different pile-forming operations in different drilling sections can be realized using the same entry section. In the regional pile section, there is no need to frequently change the position of the drilling rig. The same entry section can be used to reduce frequent drilling construction; single-point multi-pile construction occupies a small area and causes less damage to the environment. Drilling and grouting are carried out on one platform, which greatly simplifies the operation of drilling along a predetermined trajectory, improves the equipment utilization rate, reduces the cost of drilling fluid, and effectively shortens the drilling time; the diameter of the pile formed by the grouting work that only injects high-pressure cement slurry is relatively small. By using single-point multi-pile construction, a large-diameter combined pile body can be formed, which can meet the requirements of a larger diameter for the reinforced area in the underground space;

[0095] 5. By using a horizontal directional drilling rig, an entry angle of 0-90° can be achieved. The larger the entry angle, the less drill pipe is consumed by the path, and it is more capable of drilling into the middle of surface buildings;

[0096] 6. During the grouting work process, the stress in the underground grouting hole can be almost in the original state through the slurry suction pipe, so as to realize micro-disturbance of the surrounding soil environment, which will protect the surrounding underground tunnels, pipelines and above-ground structures that are extremely sensitive to settlement;

[0097] 7. Install multiple roller cutters and spurs on the guide plate at the front end of the drill bit. When encountering hard strata or strata with underground obstacles during the drilling process, the roller cutters and spurs can break the rock and soil mass through high-frequency vibration to complete smooth drilling. It can adapt to a wider range of strata.

[0098] Although the embodiments of the present application have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present application. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present application is not limited to specific details and the illustrations shown and described herein.

Claims

1. An integrated trenchless low-disturbance single-point multi-pile double high-pressure jet grouting method for an integrated trenchless low-disturbance single-point multi-pile double high-pressure jet grouting system. The system includes a drill bit, a drill pipe, a grouting pipe, a horizontal directional drill, and a grouting pump. The drill bit is installed at the front end of the drill pipe; one end of the grouting pipe is connected to the tail end of the drill pipe, and the other end is fixed to the horizontal directional drill; the grouting pump is connected to the grouting pipe; a high-pressure cement slurry channel and a high-pressure water-air channel are provided inside the drill pipe, and a slurry suction pipe is fixed on the outer surface of the drill pipe; the drill bit includes a main body rod portion fixedly connected to the drill pipe and a guide plate connected to the main body rod portion. The main body rod portion is provided with a high-pressure water-air nozzle communicating with the high-pressure water-air channel, a high-pressure nozzle communicating with the high-pressure cement slurry channel, and a low-pressure nozzle communicating with the high-pressure water-air channel. The guide plate includes a plurality of rolling blades and spines for rock breaking arranged on its periphery. A vibration motor for driving the rolling blades and spines to vibrate is provided at a position of the main body rod portion close to the guide plate. It is characterized in that, The method comprises the following steps: Step 1: In the working pit at the drilling point, drill the drill bit along a predetermined trajectory to the starting point of the grouting area; Step 2: Adjust the drilling direction, drill towards the first grouting area, and stop at the grouting end point; Step 3: Pull back the drill pipe, the drill pipe drives the drill bit to rotate for high-pressure rotary jet grouting. Meanwhile, the ground pressure detection hole monitors the slurry pressure in the hole in real time. If the slurry pressure is greater than the original ground stress here, execute Step 4; Step 4: Start the operation of the slurry suction pipe, suck out the slurry, and reduce the slurry pressure until it is reduced to the original ground stress; Step 5: After the drill pipe is pulled back to the starting point of the grouting area, adjust the drilling direction, drill towards the second grouting area, and stop at the grouting end point, then execute Steps 3 and 4; Step 6: After the grouting work in the grouting area is completed, pull back the drill pipe and the drill bit to the ground until the drill bit disengages from the soil mass.

2. The method according to claim 1, wherein: During the drilling process, cut the soil mass by the slurry ejected from the guiding plate and the low-pressure nozzle at the front end of the drill bit; when encountering a hard stratum or a stratum with underground obstacles, use vibration to make the rolling blades and spikes on the guiding plate damage the rock and soil mass to complete the drilling.

3. The method according to claim 1, wherein: Before Step 1, it further includes: On-site investigation to determine the topography, underground tunnels, pipelines and above-ground structures at the construction site; Trajectory design, design the predetermined trajectory during drilling according to the results of on-site investigation and the expected grouting design requirements; Inspection of construction equipment to detect whether each construction equipment is normal; Preparation of the working pit at the drilling point, dig out the working pit at the drilling point.

4. The method according to claim 1, wherein: In Step 4, the number of the slurry suction pipes is multiple, and the multiple slurry suction pipes are uniformly arranged along the circumferential direction of the drill pipe.

5. The method according to claim 4, wherein: The slurry suction pipe is fixed to the outer surface of the drill pipe through a slurry suction pipe holder.

6. The method according to claim 2, characterized in that: The rolling blades and the spikes are arranged alternately.

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