CN110094169A - A kind of threaded pile drill stem for reinforcing local mud and the ground screw pile forming method comprising mud - Google Patents

Abstract

The invention discloses a threaded pile drill pipe for reinforcing a local mud layer and a threaded pile forming method for a foundation thread pile containing a mud layer. Spray drilling tool splitter, the upper part of the drill pipe is socketed with the power unit, the inner upper part of the drill pipe is provided with a powder ring cavity and an air ring cavity coaxial with the filling cavity, and the rotary jet drilling tool splitter is equipped with a corresponding connected drill pipe The passages of the pouring chamber, the powder ring chamber and the air ring chamber are respectively used to connect the high-pressure fluid concrete pump, the high-pressure powder pump, and the high-pressure air pump at the outer entrances of each passage. The radial nozzle, the end face of the nozzle is a concentric central powder injection hole and an outer ring air injection hole, the powder injection hole is connected with the powder ring cavity, and the air injection hole is connected with the air ring cavity. Use this special drill pipe to reinforce the silt sandwich layer when forming a hole to form a threaded pile with an overall structure.

Description

Threaded pile drill pipe for reinforcing local silt layer and foundation thread containing silt layer Pile method

technical field

The invention relates to the technical field of civil engineering pile forming technology, more specifically, it relates to a threaded pile drill pipe for reinforcing a local mud layer and a method for forming a foundation threaded pile containing the mud layer.

Background technique

The threaded pile and its pile-forming method are new pile types based on the long helical drilled pile and the Japanese steel drill-dimensional full-threaded prefabricated pile, which changes the interaction mode between the pile and the soil, and the interface between the pile and the soil A mechanical occlusion is formed, and the principle of "screws are stronger than nails" in common sense is applied to pile construction, so that its stronger characteristics can be realized. The surface of the threaded pile is threaded, which is formed by rotating and extruding the surrounding soil through a special drill pipe with screw teeth. No or a little soil is discharged, so that the pile and soil formed in the later stage have a better extrusion force connection, which is better than ordinary piles. Cast-in-situ piles are rotary excavated and then poured into the pile body. The "Technical Regulations for Threaded Pile" JGJ/T379-2016 issued by the Ministry of Housing and Urban-Rural Development is the first technical regulation for threaded piles. Compared with ordinary cast-in-situ piles, this pile type can save 30% of the cost, and it is a modern and advanced pile type. Apps are being promoted now.

During construction, a special pile driver with synchronous technology is used. When drilling at a constant speed, it will synchronously drop a pitch every time it rotates, forming threads in the soil, and stop drilling when it reaches the design depth; when lifting the drill at a constant speed, the drill pipe Rotate one circle in the opposite direction, synchronously rise one pitch, and at the same time pump the fluid concrete to solidify into piles.

The foundation soil belongs to the earth's surface rock and soil, which is formed through complex physical, chemical and biological processes in nature. The geological survey results generally show a layered distribution. The resistance of the pile tip and the side friction of the pile body are used as the bearing capacity of the pile foundation. If there is a muddy soft soil layer with a high water content in the middle, not only will the concrete at the edge of the drill pipe be segregated and dispersed into the silt during the construction stage when the fluid concrete is pumped. In this part, the density of concrete piles is loose, and the pump pressure is difficult to control. The current mixing piles use mud retaining walls or immersed tubes to prevent dispersion, but these two measures cannot be taken for threaded piles; moreover, this part has relatively high water content. The high silt soft soil layer has little effect on the side friction resistance of the formed concrete pile, even if the pile side is threaded, it cannot provide a good bearing contribution to the pile.

Contents of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a threaded pile drill pipe for reinforcing the local silt layer that solves the above problems, which can be used to form threaded piles on foundations containing silt layers, and the silt sandwich layer Reinforced to form a threaded wall, while providing a method for forming threaded piles on foundations containing silt layers.

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

A threaded pile drill pipe for reinforcing local silt layer, including drill pipe, rotary jet drilling tool diverter, and power unit, the surface of the drill pipe body is threaded, the inner shaft center runs through the pouring chamber up and down, and the top of the drill pipe is connected to the jet jet rotary Drilling tool splitter, the upper part of the drill pipe is socketed with the power unit, the inner upper section of the drill pipe is provided with a powder ring cavity and an air ring cavity coaxial with the filling cavity, and the rotary jet drilling tool splitter is equipped with a corresponding connected drill pipe perfusion cavity, powder ring cavity, and air ring cavity. The outer entrances of each channel are used to connect to the high-pressure fluid concrete pump, high-pressure powder pump, and high-pressure air pump respectively. Radial nozzle, the end face of the nozzle is concentric with the central powder injection hole and the outer ring air injection hole, the powder injection hole is connected with the powder ring cavity, and the air injection hole is connected with the air ring cavity.

The technical solution for further improvement of the present invention is that the powder ring cavity and the air ring cavity in the upper section of the drill pipe first diverge in the upper part and extend radially to form a concentric center powder through hole and an outer ring air through hole on the peripheral surface of the drill pipe, and then turn to the vertical direction. It extends downward and communicates with the nozzle below. Travels through a small volume through hole and ends up with a stronger jet at the nozzle.

The technical solution for further improvement of the present invention is that a signal line channel is provided on the side wall of the perfusion chamber, and a signal cable is installed in the signal line channel. The cable channel provided in the drilling tool diverter is connected with the output port of the external pressure signal. The pressure sensor measures the pressure in real time during the drilling process, which is convenient for proper operation according to the actual working conditions.

The technical solution for further improvement of the present invention is that there is a gap between the front end of the nozzle and the peripheral wall of the drill pipe shaft, and the front end of the nozzle is recessed in the peripheral wall of the shaft. First, when the drill pipe wall is spinning down, the wall surface cuts the soil, which can further prevent the rock and soil around the drill pipe from squeezing the nozzle and blocking the nozzle hole; second, the high-pressure injection powder and air can quickly pass through the virtual soil in the gap and hit the rock outside the wall Soil to reach the designed spray depth.

The further improved technical solution of the present invention is that the center powder injection hole of the nozzle is arranged horizontally, and the outer ring air injection hole is inclined from the back to the front to the center. The air spray hole sprays air obliquely toward the axis of the central spray hole, and forms mutual interference with the powder spray flow sprayed from the central hole, so that the spray powder and water-soil can be evenly mixed.

The technical solution for further improvement of the present invention is that the bottom of the drill rod is in the shape of an inverted truncated cone, including the bottom end of the rod and a bonnet that blocks the pouring chamber, a cable channel is provided in the bonnet, and a pressure sensor connected to the bonnet forms a drill bit. The bottom of the drill pipe is in the shape of an inverted cone as a whole, and the valve cover is designed in the cone surface, so that no virtual soil will be formed at the bottom of the drill hole, and the connection between the pile and the foundation is stronger after the pile is formed.

The invention further improves the technical solution as follows: a gap is excavated on the side wall of the rod body on one side of the perfusion cavity at the bottom end of the rod, the upper part of the valve cover is hinged in the gap, and the other side of the valve cover is provided with a convex clamping platform, and the convex clamping platform is clamped at the bottom of the rod In the card slot opened at the bottom of the other side of the perfusion cavity at the end. When lifting the drill to pump concrete, the valve cover opens under the impact, the structure is simple and the operability is good.

The present invention also provides a pile-forming method for foundation threaded piles comprising a silt layer, using any one of claims 1 to 7 to reinforce the threaded pile drill pipe of the local silt layer for operation, comprising the following steps:

(1) Close the valve cover at the bottom of the drill pipe;

(2) Start the power unit, slowly drill and screw in the foundation to be piled, and drill a pitch for each rotation;

(3) The depth from the surface to the upper surface of the silt layer is h1, the depth from the surface to the bottom of the silt layer is h2, and the distance from the nozzle of the drill pipe to the drill bit is h. When drilling to h1+h, start the high-pressure powder pump and high-pressure The air pump makes the high-pressure powder and high-pressure air respectively enter the powder ring cavity and the air ring cavity through the upper and outer inlets of the rotary jet drilling tool splitter, and spray out from the nozzle; stop spraying when drilling reaches h2+h; drilling continues until Drilling stop at design depth;

(4) Lift the drill after the initial setting of the silt layer reaches the preset reinforcement strength, and at the same time start the high-pressure fluid concrete pump to pump the fluid concrete through the upper and outer inlets of the diverter of the rotary grouting drilling tool; One rotation to the direction should increase one pitch at the same time;

(5) Stop pumping when the pumped concrete reaches the design elevation, and stop drilling when the drill bit is lifted off the surface.

The further improvement scheme of the present invention is that the drill bit at the bottom end of the drill pipe is a pressure sensor, and when the value of the pressure sensor of the drill bit reaches the soft soil value of the silt layer with a relatively large water content detected by static contact in the geological exploration data, the rotational speed of the drill pipe according to the injection design , injection pressure, and injection volume for injection reinforcement operations. The drill pipe rotation speed is less than the original rotation speed, 0-7r/min, and the injection pressure is 10-20Mpa. The injection volume is designed and calculated according to factors such as water content, thickness, and injection depth of different silt soils. At present, the existing technology does not consider the similarities and differences of layered soil properties, and adopts the same construction design parameters. The layered design of the present invention has a good reinforcement effect of the silt layer.

The further improvement of the present invention is that in step (3), when the hole is drilled to h1+h-0.5 meters, the high-pressure powder pump and the high-pressure air pump are started, so that the high-pressure powder and high-pressure air respectively pass through the upper and outer parts of the rotary jet drilling tool diverter. The inlet enters the powder ring cavity, the air ring cavity, and sprays out from the nozzle; stop spraying when the hole reaches h2+h+0.5 meters. The purpose of increasing the vertical spraying distance of 0.5 meters above and below the silty soil layer is to connect with the upper and lower soil layers, so that the threaded pile body thread part formed in the later stage has a continuous high pile-soil bite force.

Beneficial effects of the present invention:

1. The spraying reinforcement of this application is carried out in the muddy soft soil foundation, and the surrounding medium is water and soil. Although the nozzle of the drill pipe has a large spraying pressure, the attenuation is still fast, and the cutting range is small. In order to expand the spraying powder The reinforcement range of the nozzle is to increase the air injection hole coaxially around the center powder injection hole of the nozzle to form a ring-shaped gas injection ring. When the two are injected at the same time, a protective film of air is formed around the central injection flow. This kind of When the injection method is used in the liquid medium, it can reduce the attenuation of the injection pressure, making it as close as possible to the pressure attenuation rate when spraying in the air, thereby expanding the injection radius; in addition, the air injection hole is sprayed obliquely to the axis of the central injection hole The air interferes with the powder jet flow ejected from the center hole, so that the spray powder and water-soil can be evenly mixed.

2. This application is a new drilling injection method. The existing pouring technology is to pump fluid concrete from the tip of the drill pipe when lifting the drill pipe. The fluid concrete pumped in the mud layer will segregate and disperse into the mud, and concrete will appear. The density of the pile body is loose in this part, and it is more difficult to form threads. The present invention considers that there is a certain coagulation time for the powder to be sprayed into the muddy soft soil with higher water content, and when the drill is tripped, the powder is sprayed by rotation until the drill is lifted and the concrete is pressed to the spraying position for a certain period of time, and this time period is applied mechanically as Make the reinforced body better condense to ensure that the pumped fluid concrete is pumped and compacted under a certain pressure to form a threaded pile section.

3. The drill bit of the drill pipe adopts a pressure sensor, which can detect the layered structure of the foundation when drilling, and compare and verify the value of the muddy soft soil with a large water content in the layer detected by static contact in the geological exploration data. The hole depth operation is controllable. And if the piling foundation and the previous detection are wrong, it can be flexibly dealt with.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is A-A sectional schematic diagram among Fig. 1;

Fig. 3 is B-B sectional schematic diagram among Fig. 1;

Fig. 4 is a schematic diagram of a vertical section of the nozzle;

Fig. 5 is a schematic diagram of the bottom structure of the drill pipe when the bonnet is closed;

Fig. 6 is a schematic diagram of the bottom structure of the drill pipe when the bonnet is opened;

Figure 7 is a schematic diagram of the drilling operation.

Detailed ways

As shown in Figures 1 to 6, a threaded pile drill pipe for reinforcing a local mud layer according to the present invention includes a drill pipe 1, a rotary jet drilling tool diverter 2, and a power device 3, and the surface of the drill pipe 1 has a The thread 11, the inner shaft center runs through the pouring chamber 12 up and down, the top of the drill pipe 1 is rotated and connected to the rotary jet drilling tool diverter 2, the upper part of the drill pipe 1 is socketed with the power unit 3, and the inner upper part of the drill pipe 1 is opened with the pouring chamber 12 The coaxial powder ring cavity 13 and the air ring cavity 14, and the rotary jet drilling tool diverter 2 are provided with corresponding communication drill pipe perfusion chambers, powder ring cavities, and air ring cavity channels (that is, the perfusion cavity channel 22, the powder ring cavity channel 23 , air ring cavity channel 24), the outer entrances of each channel are respectively used to connect the high-pressure fluid state concrete pump, high-pressure powder pump, high-pressure air pump (not shown in the figure of each high-pressure pump), and the powder ring cavity 13 in the upper section of the drill pipe In the upper part, the air ring cavity 14 first diverges to the shaft peripheral surface and extends radially to form a concentric central powder through hole 131 and an outer ring air through hole 141, and then turns to extend vertically downwards to the middle. The rod in the middle of the drill pipe 1 The body peripheral surface is provided with radial nozzles 15 evenly distributed in a circle, the end faces of the nozzles 15 are concentric central powder injection holes 151 and outer ring air injection holes 152, and the center powder through holes 131 of the powder ring cavity 13 and the air ring cavity 14 The ring air through hole 141 communicates with the powder injection hole 151 and the air injection hole 152 of the lower nozzle.

A signal line channel 16 is arranged on the side wall of the perfusion chamber 12, and a signal cable is installed in the signal line channel 16. The bottom end of the signal cable is connected to the pressure sensor 4 at the bottom of the drill pipe, and the top end passes through the flow divider of the rotary jet drilling tool. The provided cable channel 25 is connected to the output port of the external pressure signal.

There is a gap 17 between the front end of the nozzle and the peripheral wall of the drill pipe shaft, and the front end of the nozzle is recessed in the peripheral wall of the shaft. The central powder injection hole 151 of the nozzle is arranged horizontally, and the outer ring air injection hole 152 is inclined toward the center from the back to the front.

The bottom of the drill pipe 1 is in the shape of an inverted truncated cone, including a bottom end 18 of the rod and a bonnet 5 for blocking the perfusion chamber. A cable channel is arranged in the bonnet 5 and a drill bit is formed by a pressure sensor 4 connected to the bonnet. A notch 181 is excavated on the side wall of the rod body at the bottom end 18 of the perfusion chamber, and a connecting rod 51 is hinged in the notch 181 on one side of the valve cover 5 through a rotating shaft. It is connected in the draw-in groove 182 provided at the bottom of the other side of the perfusion chamber at the bottom of the rod.

The foundation threaded pile forming method including the silt layer uses the above-mentioned threaded pile drill pipe for operation, as shown in Figure 7:

(1) Close the valve cover at the bottom of the drill pipe;

(2) Start the power unit, slowly drill and screw in the foundation to be piled, and drill a pitch for each rotation;

(3) The depth from the surface to the upper surface of the silt layer is h1, the depth from the surface to the bottom of the silt layer is h2, and the distance from the nozzle of the drill pipe to the drill bit is h. When the hole reaches h1+h-0.5 meters, start the high-pressure powder The pump and the high-pressure air pump make the high-pressure powder and high-pressure air respectively enter the powder ring cavity and the air ring cavity through the upper and outer inlets of the rotary jet drilling tool diverter, and then spray out from the nozzle. Portland cement", "special cement", etc.> and quick-setting powder <such as the mixture of "alkali-free, low-alkali, alkaline accelerator" recommended by the National Chinese Academy of Sciences that can accelerate early strength. -6%>, pre-mixed evenly, no need to mix in the soil; the reinforcement powder and the quick-setting powder solidify when they meet water, and there is no need to consider condensation to block the spray channel after a certain duration in the nozzle; when drilling to h2+h Stop spraying at +0.5m; continue drilling to the design depth and stop drilling;

(4) Lift the drill after the initial setting of the silt layer reaches the preset reinforcement strength, and at the same time start the high-pressure fluid concrete pump to pump the fluid concrete through the upper and outer inlets of the diverter of the rotary grouting drilling tool; One rotation to the direction should increase one pitch at the same time;

(5) Stop pumping when the pumped concrete reaches the design elevation, and stop drilling when the drill bit is lifted off the surface.

Since the drill bit at the bottom of the drill pipe is a pressure sensor, when the value of the pressure sensor of the drill bit reaches the soft soil value of the silt layer with a large water content detected by the static contact detection in the geological exploration data, the drill pipe speed, injection pressure, and injection volume designed according to the injection For spray reinforcement, the drill pipe speed is less than the original speed, 0-7r/min, and the spray pressure is 10-20Mpa. The spray volume is designed and calculated according to the water content, thickness, spray depth and other factors of different silt soils.

The above descriptions are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention should also be regarded as the protection scope of the present invention.

Claims (10)

1. A threaded pile drill pipe for reinforcing local silt layer, including drill pipe (1), rotary jet drilling tool diverter (2), power device (3), and the surface of the drill pipe (1) has threads (11 ), the inner axis runs through the perfusion chamber (12) up and down, the top of the drill pipe (1) is rotated to connect with the rotary jet drilling tool diverter (2), and the upper shaft of the drill pipe (1) is socketed with the power unit (3), which is characterized in that : The upper part of the drill pipe (1) is provided with a powder ring chamber (13) and an air ring chamber (14) coaxial with the perfusion chamber (12), and a corresponding connected drill pipe is provided in the rotary jet drilling tool splitter (2) The passages of the pouring chamber, the powder ring chamber and the air ring chamber are respectively used to connect the high-pressure fluid state concrete pump, the high-pressure powder pump, and the high-pressure air pump at the outer entrances of each passage. A circle of radial nozzles (15) at intervals, the end face of the nozzle (15) is concentric with the central powder injection hole (151) and the outer ring air injection hole (152), the powder injection hole (151) communicates with the powder ring cavity (13) , the air spray hole (152) communicates with the air ring cavity (14). 2. A threaded pile drill pipe for reinforcing local silt layer according to claim 1, characterized in that: the powder ring chamber (13) and the air ring chamber (14) in the upper part of the drill pipe diverge to the shaft first The peripheral surface radially extends into a concentric central powder through hole (131) and an outer ring air through hole (141), and then turns to extend vertically downwards to communicate with the nozzle (15) below. 3. A threaded pile drill pipe for reinforcing local silt layers according to claim 1, characterized in that: a signal line channel (16) is provided on the side wall of the pouring cavity (12), and the signal line channel (16) is Put through the signal cable, the bottom end of the signal cable is connected to the pressure sensor (4) at the bottom of the drill pipe, and the top end of the signal cable passes through the cable channel (25) provided in the flow diverter of the jet-jet drilling tool to connect to the external pressure signal output port. 4. A threaded pile drill pipe for reinforcing local silt layer according to claim 1, characterized in that there is a distance gap (17) between the front end of the nozzle and the peripheral wall of the drill pipe shaft, and the front end of the nozzle is recessed in the peripheral wall of the shaft . 5. A threaded pile drill pipe for reinforcing local silt layer according to claim 1, characterized in that: the central powder injection hole (151) of the nozzle is arranged horizontally, and the outer ring air injection hole (152) is directed from the back to the front Center tilted. 6. A threaded pile drill pipe for reinforcing local silt layer according to claim 1, characterized in that: the bottom of the drill pipe (1) is in the shape of an inverted frustum, including the bottom end (18) of the rod and the part for sealing the pouring cavity The bonnet (5), the cable channel is arranged in the bonnet (5), and the drill bit formed by the pressure sensor (4) connected on the bonnet. 7. A threaded pile drill pipe for reinforcing local silt layers according to claim 6, characterized in that: a notch (181) is excavated on the side wall of the shaft at the bottom end (18) of the filling cavity, and the valve cover (5 ) on one side is provided with a connecting rod (51) hinged in the gap (181), and on the other side of the bonnet (5) is provided with a convex clamping platform (52), which is clamped at the bottom of the rod and opened at the bottom of the other side of the perfusion chamber. in the card slot (182). 8. The foundation threaded pile forming method comprising the silt layer is characterized in that, using any one of claims 1 to 7 to reinforce the threaded pile drill pipe of the local silt layer to perform operation, comprising the following steps: (1) Close the valve cover at the bottom of the drill pipe; (2) Start the power unit, slowly drill and screw in the foundation to be piled, and drill a pitch for each rotation; (3) The depth from the surface to the upper surface of the silt layer is h1, the depth from the surface to the bottom of the silt layer is h2, and the distance from the nozzle of the drill pipe to the drill bit is h. When drilling to h1+h, start the high-pressure powder pump and high-pressure The air pump makes the high-pressure powder and high-pressure air respectively enter the powder ring cavity and the air ring cavity through the upper and outer inlets of the rotary jet drilling tool splitter, and spray out from the nozzle; stop spraying when drilling reaches h2+h; drilling continues until Drilling stop at design depth; (4) Lift the drill after the initial setting of the silt layer reaches the preset reinforcement strength, and at the same time start the high-pressure fluid concrete pump to pump the fluid concrete through the upper and outer inlets of the diverter of the rotary grouting drilling tool; One rotation to the direction should increase one pitch at the same time; (5) Stop pumping when the pumped concrete reaches the design elevation, and stop drilling when the drill bit is lifted off the surface. 9. the foundation threaded pile forming method comprising the silt layer according to claim 8, is characterized in that: the drill bit at the bottom of the drill pipe is a pressure sensor, when the drill bit pressure sensor value reaches the content of static contact detection in the geological exploration data When the amount of water is large and the value of the soft soil in the silt layer is large, the spray reinforcement operation is carried out according to the drill pipe speed, spray pressure, and spray volume designed for spraying. The drill pipe speed is less than the original speed, 0-7r/min, and the spray pressure is 10-20Mpa. The calculated values are designed based on factors such as water content, thickness, and spray depth of different silt soils. 10. The pile-forming method of foundation threaded piles containing silt layer according to claim 8, characterized in that: in step (3), when the hole is drilled to h1+h-0.5 meters, start the high-pressure powder pump and high-pressure air pump, Let the high-pressure powder and high-pressure air enter the powder ring cavity and the air ring cavity respectively through the upper and outer inlets of the diverter of the rotary jet drilling tool, and spray out from the nozzle; stop spraying when the drilling hole reaches h2+h+0.5 meters.