Mixing pile machine drill bit for improving construction quality of cement-soil retaining wall and construction method

Abstract

The invention discloses a mixing pile machine drill bit capable of improving the construction quality of a cement soil retaining wall and a construction method, the drill bit can accurately control the slurry outlet speed and flow of cement slurry through air bag extrusion and blade mixing, and therefore real-time monitoring and feedback of different soil body depths are achieved. In addition, a plurality of fins and cutting fins are arranged on the drill bit, it is guaranteed that cement slurry is fully diffused to the edge of the pile body and fully stirred with soil slurry, and the pile forming quality of the cement-soil pile is improved. And the cement mixing amount can be adjusted in real time by changing the number of the fins, so that the construction effect is optimized. The drill bit is easy to operate, does not need to frequently adjust a slurry discharge pump and saves manpower and material resources.

Description

Technical Field

[0001] The invention belongs to the field of geotechnical engineering support structure construction, in particular to a pile mixing machine drill bit for improving the construction quality of cement soil retaining walls. Background Art

[0002] As the main load-bearing structure of the grid-type gravity retaining wall in soft soil areas, cement-soil mixing piles use cement as the main curing agent. A mixing pile machine is used to spray cement into the soil and fully mix it, so that a series of physical and chemical reactions occur between the cement and the soil, and the soft soil is hardened into piles. The cement-soil mixing piles overlap each other to form a retaining wall entity and use gravity to stop the soil. Cement mixing piles are divided into single-axis, double-axis and three-axis mixing piles according to the main construction methods used. There are some problems with the traditional cement mixing pile machine pile-forming method, such as the poor fluidity of cement slurry in the soil and the difficulty in evenly spreading, which causes a large amount of cement slurry to accumulate near the spray nozzle, while the amount of slurry is seriously insufficient at a slightly farther position, and the spray nozzle is also easily blocked by broken soil, which naturally leads to a lack of cement slurry in the soil. Therefore, after mixing, the cement soil of the pile body is not dense and uniform, which seriously reduces the quality of the pile. In addition, different soils at different depths have different demands for cement slurry. Traditional cement mixing pile machines can only spray cement slurry at a constant flow rate, which will cause the pile quality in strata with poor soil conditions to fail to meet the bearing capacity requirements, and will also cause a waste of cement slurry in strata with good soil conditions. It is impossible to adjust the cement slurry flow in real time according to the specific soil conditions. Summary of the invention

[0003] The purpose of the present invention is to provide a pile mixing drill bit that improves the construction quality of cement soil retaining walls based on the above-mentioned deficiencies of the prior art. The pile mixing drill bit controls the cement slurry flow rate of different depths and different soils by supplying air to expand the air bag and squeeze the cement slurry into the soil, and utilizes the stirring of the outer inclined blades to fully mix the cement slurry with the soil to improve the pile quality. At the same time, the electronic monitoring device installed on the upper and lower blades utilizes the different resistance characteristics of different soils with different cement contents to monitor the cement content, and feeds back relevant information to the control console in real time, thereby guiding the subsequent construction of the pile mixing machine.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall, wherein a plurality of slurry outlet holes are opened on the drill rod for discharging cement slurry, a drill cone is welded on the end of the drill rod, and two blades are welded on the left and right sides of the drill rod.

[0006] The blades are divided into upper blades and lower blades; through bolt holes are opened on the blades, and the blades are divided into upper slide grooves and lower slide grooves;

[0007] The upper slide groove of the upper blade uses fixing bolts to fix the monitoring wing piece through the bolt holes, and the lower slide groove uses fixing bolts to fix the cutting wing piece through the bolt holes;

[0008] The lower slide groove on the lower blade uses fixing bolts to fix the monitoring wing through the bolt holes, and the upper slide groove uses fixing bolts to fix the cutting wing through the bolt holes;

[0009] The monitoring wing is provided with a monitoring wing bolt hole at the monitoring wing base. The monitoring wing slides into the lower slide groove and the upper slide groove through the monitoring wing base and is fixed to the blade using fixing bolts.

[0010] Furthermore, the monitoring wing is provided with a monitoring wing cutting piece, which is also used for cutting soil, and a monitoring wing resistance monitoring element is installed on the front side of the monitoring wing cutting piece.

[0011] Furthermore, the cutting wing is provided with a cutting wing bolt hole on the cutting wing base, and the cutting wing slides into the lower slide groove and the upper slide groove through the cutting wing base, and is fixed to the blade using fixing bolts.

[0012] Furthermore, the cutting wing has a cutting wing cutting piece, and the cutting wing cutting piece and the cutting wing base have a certain inclination angle.

[0013] Furthermore, an airway is fixed on the inner side of the drill rod, an airbag baffle is fixed on the airway, an inflatable airbag is fixed under the airbag baffle, and the airbag becomes cylindrical after being inflated and is placed between the drill rod and the airway.

[0014] Furthermore, symmetrical air outlet holes are opened on the airway inside the airbag; a fixed rotating shaft is fixed on the upper part of the airway, and a slurry return baffle is connected to the fixed rotating shaft inside the drill rod.

[0015] Furthermore, a rotating slurry discharge plate is fixed on the fixed rotating shaft, and the slurry discharge plate rotates around the fixed rotating shaft under the slurry return baffle plate, and can completely block the cavity between the slurry return baffle plate and the fixed rotating shaft, thereby preventing the cement slurry from flowing back.

[0016] The construction method of the pile mixing machine drill bit for improving the construction quality of the cement soil retaining wall specifically comprises the following steps:

[0017] S1. Before the construction of cement-soil mixing pile retaining wall is implemented, the strata in the construction area shall be explored in detail. The main results of the exploration shall include the properties of each soil layer in the construction cement-soil mixing pile area, soil type, strength index and groundwater distribution. After obtaining the exploration data of each soil layer, cement slurry shall be added to the soil at each depth to make rectangular parallelepiped samples on the ground, and the resistance of the samples with different cement slurry contents shall be measured under a certain voltage to form experimental results with one-to-one correspondence between cement content and resistance characteristics.

[0018] S2, the upper chute of the upper blade and the lower chute of the lower blade are each equipped with an even number of monitoring fins; the lower chute of the upper blade and the upper chute of the lower blade are each equipped with a plurality of the cutting fins; the monitoring fin resistance monitoring element of the monitoring fin transmits information to the ground control console through electronic signals; if the pile drilling situation is not ideal, the cutting fins are increased or decreased on the original basis, so as to make the drilling process and the mixing process more efficient;

[0019] S3, connect the drill rod to the rotating shaft of the pile mixing machine, move the pile mixing machine to the construction site for construction work, the drill cone, cutting blade and monitoring blade efficiently cut the soil, make the drill bit move underground, and after reaching the bottom elevation of the cement soil pile, move the drill bit upward and start to spray cement slurry, the cement slurry is transported from the ground to the slurry outlet through the drill rod, and is thrown out to the outside of the pile body under the centrifugal action of the cutting blades of the upper and lower blades, thereby taking the cement slurry away from the axial area, so that the cement content of the entire cross section of the cement pile remains consistent;

[0020] S4. When the soil quality at a certain depth is poor, the air pump on the ground is used to inflate the airbag through the air channel. The high-pressure gas enters the airbag through the air outlet holes on the air channel. The airbag is inflated and expands, squeezing the cement slurry between the airbag and the drill pipe and accelerating it to be discharged into the soil through the slurry outlet holes, thereby increasing the cement content in the soil area without changing the pile speed;

[0021] S5. An airbag baffle is fixed on the upper part of the airbag to prevent the airbag from clogging the slurry discharge pipe after expansion; and a slurry discharge piece is fixed above the airbag baffle. The slurry discharge piece can only rotate on the west side due to the obstruction of the slurry return baffle; when the cement slurry flows from the ground to the drill bit, the slurry discharge piece opens under the impact force to ensure the normal transportation of the cement slurry. If the cement slurry is not sprayed smoothly to the soil due to excessive pressure, the slurry discharge piece automatically closes under the pressure from the lower side to prevent the cement slurry from flowing back to the ground;

[0022] S6. During the rotation of the drill bit, there will always be a cubic soil between the two monitoring wings. The monitoring wing resistance monitoring element monitors the resistance data of the cubic soil in real time, so as to obtain the one-to-one correspondence between cement content and resistance characteristics through pre-construction experiments to calculate whether the cement content meets the design strength requirements. If it does not meet the design requirements, increase the amount of cement slurry in this layer of soil;

[0023] Furthermore, the monitoring wing resistance monitoring element should be firmly fixed in the monitoring wing monitoring element fixing hole, and sufficient power supply should be ensured before each cement pile construction; when monitoring the cubic soil resistance, the rotation speed of the drill bit should be slowed down.

[0024] Furthermore, when inflating the airbag to accelerate the cement slurry injection, the inflation speed should be controlled not to be too fast to prevent excessive pressure from causing severe interference to the soil around the drill bit; the fixed rotating shaft should have a limit device, and the slurry outlet piece should always maintain an angle of less than degrees with the slurry return baffle piece on that side, otherwise the backflow prevention device will fail.

[0025] Compared with the prior art, the beneficial effects of the present invention are: the pile mixing machine drill bit that efficiently improves the construction quality of cement soil retaining walls improves the construction quality of cement soil piles according to the actual conditions of different soil bodies and different depths, and achieves real-time monitoring, real-time feedback and real-time adjustment.

[0026] Compared with the traditional method of increasing the slurry discharge pump on the ground, the slurry discharge speed of cement slurry is adjusted by air bag squeezing, which is faster and more real-time. It is also simple to operate, saves time and effort, and avoids the tedious operation of adjusting the slurry discharge pump multiple times.

[0027] In addition, multiple fins are installed on the upper and lower blades, and the inclined cutting blades of the cutting fins ensure that the cement slurry is fully diffused to the edge of the pile body and the soil slurry is fully mixed, providing a higher guarantee for the quality of the cement soil pile.

[0028] Finally, the monitoring wings with adjustable spacing monitor the construction soil conditions in real time, eliminating quality risks during the construction phase and effectively solving the lag in detection after the construction is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0030] Figure 1 It is a structural upper side view of a drill bit of a mixing pile machine for efficiently improving the construction quality of a cement soil retaining wall in the present invention;

[0031] Figure 2 It is a lower side view of the structure of the drill bit of the mixing pile machine for efficiently improving the construction quality of the cement soil retaining wall of the present invention;

[0032] Figure 3 It is a partial cross-sectional view of the structure of the drill bit of the pile mixing machine in the present invention;

[0033] Figure 4 It is a schematic diagram of the internal airway structure in the present invention;

[0034] Figure 5 It is the internal air bag and anti-backflow device in the present invention;

[0035] Figure 6 It is the cement mixing pile machine drill bit that cuts the middle wing;

[0036] Figure 7 It is the upper and lower blades of the cement mixing pile machine drill bit cutting monitoring;

[0037] In the figure: 1, drill rod; 2, blade; 3, airway; 4, monitoring wing; 5, cutting wing; 6, drill cone; 7, slurry outlet hole; 8, air bag; 9, anti-backflow device; 21, lower slide groove; 22, upper slide groove; 23, fixing bolt; 24, bolt hole; 31, air bag baffle; 32, air outlet hole; 41, monitoring wing bolt hole; 42, monitoring wing base; 43, monitoring wing cutting piece; 44, monitoring wing resistor monitoring element; 45, monitoring wing monitoring element fixing hole; 51, cutting wing bolt hole; 52, cutting wing base; 53, cutting wing cutting piece; 91, back slurry baffle; 92, slurry outlet piece; 93, fixed shaft; DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] Embodiment 1

[0040] See also Figure 1-7The present invention provides a technical solution: a pile mixing machine drill bit for improving the construction quality of cement soil retaining wall, wherein 16 slurry outlet holes 7 are opened on the drill rod 1 for discharging cement slurry, and a drill cone 6 is welded at the end of the drill rod 1, and two blades 2 are welded on the left and right sides of the drill rod 1, respectively, and the blades 2 are divided into an upper blade and a lower blade; a through bolt hole 24 is opened on the blade 2, and the blade 2 is divided into an upper slide groove 22 and a lower slide groove 21; the upper slide groove 22 of the upper blade 2 uses a fixing bolt 23 to fix the monitoring wing 4 through the bolt hole 24, and the lower slide groove 21 uses a fixing bolt 23 to fix the cutting wing 5 through the bolt hole 24; the lower slide groove 21 of the lower blade 2 uses a fixing bolt 23 to fix the monitoring wing 4 through the bolt hole 24, and the upper slide groove 22 uses a fixing bolt 23 to fix the cutting wing 5 through the bolt hole 24; the monitoring wing 4 has a monitoring wing bolt hole 41 opened on the monitoring wing base 42, slides into the lower slide groove 21 and the upper slide groove 22 through the monitoring wing base 42, and is fixed to the blade 2 with a fixing bolt 23. The monitoring wing 4 is provided with a monitoring wing cutting piece 43, which is also used for cutting soil. A monitoring wing resistance monitoring element 44 is installed on the front of the monitoring wing cutting piece 43; the cutting wing 5 is provided with a cutting wing bolt hole 51 on the cutting wing base 52, which slides into the lower slide groove 21 and the upper slide groove 22 through the cutting wing base 52, and is fixed to the blade with a fixing bolt 23. The cutting wing 5 is provided with a cutting wing cutting piece 53, and the cutting wing cutting piece 53 has a certain inclination angle with the cutting wing base 52; the airway 3 is fixed on the inner side of the drill rod 1, and the airbag baffle 31 is fixed on the airway 3, and an inflatable airbag 8 is fixed under the airbag baffle 31. The airbag 8 is cylindrical after being inflated and is placed between the drill rod 1 and the airway 3. Symmetrical air outlet holes 32 are provided on the air channel 3 inside the airbag 8; a fixed rotating shaft 93 is fixed on the upper part of the air channel 3, and a back-slurry baffle 91 is connected to the fixed rotating shaft 93 in the drill rod 1; a rotating slurry outlet plate 92 is fixed on the fixed rotating shaft 93, and the slurry outlet plate 92 rotates around the fixed rotating shaft 93 under the back-slurry baffle 91, and can completely block the cavity between the back-slurry baffle 91 and the fixed rotating shaft 93, thereby preventing the cement slurry from flowing back.

[0041] Embodiment 2:

[0042] like Figure 1-7 As shown, this embodiment specifically relates to a method for using a pile mixing machine drill bit to improve the construction quality of a cement soil retaining wall, which specifically includes the following steps:

[0043] S1. Before implementing the cement-soil mixing pile retaining wall construction, the strata in the construction area shall be explored in detail. The main results of the exploration shall include the properties of each soil layer in the cement-soil mixing pile construction area, soil type, strength index (such as friction angle and cohesion) and groundwater distribution; after obtaining the exploration data of each soil layer, cement slurry shall be added to the soil at each depth obtained on the ground to make rectangular specimens, and the resistance of the specimens with different cement slurry contents shall be measured under a certain voltage to form experimental results with one-to-one correspondence between cement content and resistance characteristics.

[0044] S2, the upper chute 22 of the upper blade 2 and the lower chute 21 of the lower blade 2 are each equipped with an even number of monitoring blades 4; the lower chute 21 of the upper blade 2 and the upper chute 22 of the lower blade 2 are each equipped with a plurality of the cutting blades 5. The monitoring blade resistance monitoring element 44 of the monitoring blade 4 transmits information to the ground control console through electronic signals; if the pile drilling situation is not ideal, the cutting blades 5 are increased or decreased on the original basis, so as to make the drilling process and the mixing process more efficient;

[0045] S3, connect the drill rod 1 to the rotating shaft of the pile mixing machine, move the pile mixing machine to the construction site for construction work, the drill cone 6, the cutting blade 5 and the monitoring blade 4 efficiently cut the soil, and move the drill bit underground. After reaching the bottom elevation of the cement soil pile, move the drill bit upward and start to spray cement slurry. The cement slurry is transported from the ground to the slurry outlet hole 7 through the drill rod 1, and is thrown out to the outside of the pile body under the centrifugal action of the cutting blade 5 of the upper and lower blades 2 and the cutting blade 53, thereby taking the cement slurry away from the axial area, so that the cement content of the entire cross section of the cement pile remains consistent;

[0046] S4. When the soil quality at a certain depth is poor, the air pump on the ground is used to inflate the airbag 8 through the air channel 3. The high-pressure gas enters the airbag 8 through the air outlet 32 ​​on the air channel 3. The airbag 8 is inflated and expands, and the cement slurry between the airbag 8 and the drill rod 1 is accelerated to be discharged into the soil through the slurry outlet 7, thereby increasing the cement content in the soil area without changing the pile forming speed.

[0047] S5. An airbag baffle 31 is fixed on the upper part of the airbag 8 of the air channel 3 to prevent the airbag 8 from blocking the slurry discharge pipe after expansion; and a slurry discharge plate 92 is fixed above the airbag baffle 31. The slurry discharge plate 92 can only rotate on the west side due to the obstruction of the slurry return baffle 91. When the cement slurry flows from the ground to the drill bit, the slurry discharge plate 92 opens under the impact force to ensure the normal transportation of the cement slurry. If the cement slurry is not sprayed smoothly to the soil due to excessive pressure, the slurry discharge plate 92 automatically closes under the pressure from the lower side to prevent the cement slurry from flowing back to the ground;

[0048] S6. During the rotation of the drill bit, there is always a cubic soil between the two monitoring wings 4. The monitoring wing resistance monitoring element 44 monitors the resistance data of the cubic soil in real time, so as to obtain the one-to-one correspondence between cement content and resistance characteristics through pre-construction experiments to calculate whether the cement content meets the design strength requirements. If it does not meet the design requirements, increase the amount of cement slurry in this layer of soil;

[0049] It should be noted that the monitoring wing resistance monitoring element 44 should be firmly fixed in the monitoring wing monitoring element fixing hole 45, and sufficient power supply should be ensured before each cement pile construction; when monitoring the cubic soil resistance, the rotation speed of the drill bit should be slowed down;

[0050] Embodiment 3

[0051] On the basis of the above embodiment, when the airbag is inflated to accelerate the cement slurry injection, the inflation speed should be controlled not to be too fast to prevent excessive pressure from causing severe interference to the soil around the drill bit;

[0052] The fixed rotating shaft 93 should be provided with a limiting device, and the pulp outlet plate 92 should always maintain an angle of less than 60 degrees with the pulp return baffle plate on that side, otherwise, the backflow prevention device 9 will fail.

[0053] Although embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations may be made to these embodiments without departing from the principles and spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall, characterized by: The drill rod (1) comprises a plurality of slurry outlet holes (7) for discharging cement slurry, a drill cone (6) is welded to the end of the drill rod (1), and two blades (2) are welded to the left and right sides of the drill rod (1). The blade (2) is divided into an upper blade and a lower blade; a through bolt hole (24) is opened on the blade (2), and the blade (2) is divided into an upper slide groove (22) and a lower slide groove (21); The upper slide groove (22) of the upper blade (2) is fixed to the monitoring wing (4) by using the fixing bolt (23) through the bolt hole (24), and the lower slide groove (21) is fixed to the cutting wing (5) by using the fixing bolt (23) through the bolt hole (24); The lower slide groove (21) on the lower blade (2) is fixed to the monitoring wing (4) by using the fixing bolt (23) through the bolt hole (24), and the upper slide groove (22) is fixed to the cutting wing (5) by using the fixing bolt (23) through the bolt hole (24); The monitoring wing (4) is provided with a monitoring wing bolt hole (41) on the monitoring wing base (42), and slides into the lower slide groove (21) and the upper slide groove (22) through the monitoring wing base (42), and is fixed to the blade (2) using a fixing bolt (23).

2. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall according to claim 1, characterized in that: The monitoring wing (4) is provided with a monitoring wing cutting piece (43) which is also used for cutting soil. A monitoring wing resistance monitoring element (44) is installed on the front side of the monitoring wing cutting piece (43).

3. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall according to claim 2, characterized in that: The cutting wing (5) is provided with a cutting wing bolt hole (51) on the cutting wing base (52), and slides into the lower slide groove (21) and the upper slide groove (22) through the cutting wing base (52), and is fixed to the blade using a fixing bolt (23).

4. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall according to claim 2, characterized in that: The cutting wing (5) is provided with a cutting wing cutting piece (53), and the cutting wing cutting piece (53) and the cutting wing base (52) have a certain inclination angle.

5. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall according to claim 2, characterized in that: An air passage (3) is fixed inside the drill rod (1), an air bag baffle (31) is fixed to the air passage (3), an inflatable air bag (8) is fixed below the air bag baffle (31), and the air bag (8) becomes cylindrical after being inflated and is placed between the drill rod (1) and the air passage (3).

6. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall according to claim 2, characterized in that: Symmetrical air outlet holes (32) are provided on the air passage (3) inside the air bag (8); a fixed rotating shaft (93) is fixed on the upper part of the air passage (3); and a slurry return baffle (91) is connected to the fixed rotating shaft (93) inside the drill rod (1).

7. A pile mixing machine drill bit for improving the construction quality of cement soil retaining wall according to claim 6, characterized in that: A rotatable slurry discharge plate (92) is fixed on the fixed rotating shaft (93). The slurry discharge plate (92) rotates around the fixed rotating shaft (93) under the slurry return baffle (91) and can completely block the cavity between the slurry return baffle (91) and the fixed rotating shaft (93), thereby preventing the cement slurry from flowing back.

8. A construction method for a pile mixing machine drill bit for improving the construction quality of a cement soil retaining wall, characterized in that: The specific steps include: S1. Before the construction of cement-soil mixing pile retaining wall is implemented, the strata in the construction area shall be explored in detail. The main results of the exploration shall include the properties of each soil layer in the construction cement-soil mixing pile area, soil type, strength index and groundwater distribution. After obtaining the exploration data of each soil layer, cement slurry shall be added to the soil at each depth to make rectangular parallelepiped samples on the ground, and the resistance of the samples with different cement slurry contents shall be measured under a certain voltage to form a one-to-one correspondence experimental result between cement content and resistance characteristics. S2, the upper slide groove (22) of the upper blade (2) and the lower slide groove (21) of the lower blade (2) are each installed with an even number of monitoring blades (4); the lower slide groove (21) of the upper blade (2) and the upper slide groove (22) of the lower blade (2) are each installed with a plurality of the cutting blades (5); the monitoring blade resistance monitoring element (44) of the monitoring blade (4) transmits information to the ground control console through electronic signals; if the pile drilling situation is not ideal, the cutting blades (5) are increased or decreased on the original basis, so that the drilling process and the mixing process are more efficient; S3, connecting the drill rod (1) to the rotating shaft of the pile mixing machine, moving the pile mixing machine to the construction site for construction work, the drill cone (6), the cutting blade (5) and the monitoring blade (4) efficiently cut the soil, and the drill bit moves underground. After reaching the bottom elevation of the cement soil pile, the drill bit moves upward and starts to spray cement slurry. The cement slurry is transported from the ground to the slurry outlet hole (7) through the drill rod (1), and is thrown out to the outside of the pile body under the centrifugal action of the cutting blade (53) of the upper and lower blades (2), thereby taking the cement slurry away from the axial area, so that the cement content of the entire cross section of the cement pile remains consistent; S4. When the soil quality at a certain depth is poor, the air pump on the ground is used to inflate the air bag (8) through the air channel (3). The high-pressure gas enters the air bag (8) through the air outlet hole (32) on the air channel (3). The air bag (8) is inflated and expanded, and the cement slurry between the air bag (8) and the drill rod (1) is squeezed and accelerated to be discharged into the soil through the slurry outlet hole (7), thereby increasing the cement content in the soil area without changing the pile forming speed. S5. An airbag baffle (31) is fixed on the upper part of the airbag (8) of the air passage (3) to prevent the airbag (8) from blocking the slurry discharge pipe after expansion; and a slurry discharge plate (92) is fixed above the airbag baffle (31). The slurry discharge plate (92) can only rotate on the west side due to the obstruction of the slurry return baffle (91); when the cement slurry flows from the ground to the drill bit, the slurry discharge plate (92) opens under the impact force to ensure the normal transportation of the cement slurry; if the cement slurry is not sprayed smoothly to the soil due to excessive pressure, the slurry discharge plate (92) is automatically closed under the pressure from the lower side to prevent the cement slurry from flowing back to the ground. S6. During the rotation of the drill bit, there will always be a cubic soil body between the two monitoring wings (4). The monitoring wing resistance monitoring element (44) monitors the resistance data of the cubic soil body in real time, so as to obtain the one-to-one correspondence between cement content and resistance characteristics through pre-construction experiments to deduce whether the cement content meets the design strength requirements. If it does not meet the design requirements, the amount of cement slurry in this layer of soil is increased.

9. A construction method for a pile mixing machine drill bit for improving the construction quality of a cement soil retaining wall according to claim 8, characterized in that: The flap resistance monitoring element (44) to be monitored should be firmly fixed in the flap monitoring element fixing hole (45), and sufficient power supply should be ensured before each cement pile construction; when monitoring the cubic soil resistance, the rotation speed of the drill bit should be slowed down.

10. A construction method for a pile mixing machine drill bit for improving the construction quality of a cement soil retaining wall according to claim 8, characterized in that: When the airbag is inflated to accelerate cement slurry injection, the inflation speed should be controlled not to be too fast to prevent excessive pressure from causing severe interference to the soil around the drill bit; the fixed shaft (93) should be provided with a limit device, and the slurry discharge plate (92) should always be kept at an angle of less than (60) degrees with the slurry return baffle plate on that side, otherwise the backflow prevention device (9) will fail.

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