CN110258559B

CN110258559B - Alloy material for drill bit of drilling machine and construction method of punched pile

Info

Publication number: CN110258559B
Application number: CN201910488996.8A
Authority: CN
Inventors: 张锋; 和向武; 刘洪冰; 苏自林; 欧德; 李光红
Original assignee: Ycih No13 Construction Co ltd
Current assignee: Ycih No13 Construction Co ltd
Priority date: 2017-05-07
Filing date: 2017-05-07
Publication date: 2021-07-06
Anticipated expiration: 2037-05-07
Also published as: CN107246010A; CN110258558B; CN110258559A; CN107246010B; CN110258558A

Abstract

The invention relates to the technical field of hole forming technology and cast-in-place pile forming under karst geology. The construction method of the karst geological punching pile and the drill bit material can greatly improve the pile forming quality of the punching pile. The alloy material for the drill bit comprises the following components in parts by weight: 120 parts of iron; 8.5 parts of chromium; 20 parts of nickel; 5 parts of silicon; cobalt 2; 0.8 part of iridium; 0.5 part of titanium; 0.5 part of niobium; 0.3 part of scandium; 0.5 part of tellurium; 0.8 part of beryllium; 0.1 part of strontium; 0.8 part of cesium. The alloy material has excellent performance, can greatly improve the pile forming quality of the punched pile, and reduces the incidence rate of accidents such as drill sticking, hole collapse and the like.

Description

Alloy material for drill bit of drilling machine and construction method of punched pile

The invention is a divisional application of invention patents with the application date of 2017.5.7, the application number of 201710315053.6 and the patent name of 'construction method of karst geological punching pile'.

Technical Field

The invention relates to the technical field of hole forming technology and cast-in-place pile forming under karst geology, in particular to a construction method of a punched pile in the karst geology.

Background

In the construction of building engineering at present, in order to improve the stability of buildings, a support pile needs to be fixed in an underground rock stratum so as to ensure the stability of the buildings. Therefore, the depth of the pile hole must be ensured to reach the rock layer in the formation of the pile hole, so that special equipment is needed for punching the hole underground, and redundant soil/slurry and broken stones are extruded to the two sides of the hole or are cleaned out in the punching process so as to continue to punch the hole downwards. At present, the above-mentioned punching is mainly realized by a heavy hammer (also called as a percussion bit) through a punching pile machine (i.e. a drilling machine), and the working principle of the existing punching pile machine mainly comprises: lifting the heavy hammer to a certain height, then making it drop freely after being projected, impacting contact surface, then lifting the heavy hammer, then projecting … … to reciprocate, utilizing impact kinetic energy to impact soil layer or broken rock to form hole, extruding part of broken slag and mud into hole wall, mostly becoming mud, utilizing slag-removing cylinder or other method to discharge mud out of hole, then placing reinforcing cage, pouring concrete to form pile.

The karst landform is the special landform that is formed by soluble rock under the long-term effect of corrosion nature groundwater, prior art is in the work progress of punching a hole stake, because the solution cavity is many, the bottom surface or the side in stake hole often appear the crack, breach etc. lead to the shape structure of stake hole internal face and bottom surface more complicated, the weight is because the atress is extremely uneven violently when falling back and the contact of stake hole bottom surface, lead to the weight to have very big deflection, beat seriously, can't guarantee the shaping quality in stake hole on the one hand, on the other hand also causes the support arm of punching a hole stake machine to receive huge impact. Meanwhile, due to the influence of the karst cave, in order to ensure the thickness of the bearing layer of the punched pile so as to improve the stability of the punched pile, the pile hole depth of the punched pile is usually larger, the steel rope for hoisting the percussion bit is longer, effective control is lacked in the middle section of the steel rope in the prior art, so that the deflection amount of the percussion bit is larger, the jamming of the drilling bit is often caused, the construction period is greatly influenced, and unnecessary workload is increased.

Meanwhile, due to frequent drill jamming, once the hammer head of the heavy hammer is stuck by a clay layer or is stuck by rocks or a karst cave and cannot be taken out, a winch of the punching pile machine is still in continuous operation, and a steel wire rope generates great pulling force to the heavy hammer, so that the pulling force can generate a reaction force for pulling the punching pile machine. Although the machine base of the punching pile machine is generally large in balance weight, when the drill clamping phenomenon is serious, the rear end of the whole machine frame is pulled upwards, and at the moment, if an operator cannot timely react and stop the machine, the frame turning accident is easily caused, so that the punching pile machine is easily damaged, and the life safety of the operator is harmed.

Disclosure of Invention

The invention aims to provide a construction method of a karst geological punching pile, which can greatly improve the pile forming quality of the punching pile.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: a construction method of a karst geological punching pile comprises the following steps:

A. leveling a field, paying off a pile position and digging a mud circulation pool;

B. drilling below the pile position, wherein the drilling depth is at least 5 meters into the bearing stratum;

C. embedding a pile casing and a drilling machine in place; the upper part of the side surface of the pile casing is provided with an overflow port, and the drilling machine is provided with an anti-overturning mechanism;

D. preparing slurry, performing impact drilling, and preparing the slurry in a slurry circulating pool, wherein the colloid rate of the slurry is not lower than 96%; when the depth of a pile hole is more than or equal to 4 meters in the process of percussion drilling, a protective sealing cover is arranged at the upper end of the protective cylinder, a guide hole is formed in the center of the protective sealing cover, and a steel rope for hoisting a percussion drill bit penetrates through the guide hole;

E. checking the formed hole and cleaning the hole for the first time;

F. manufacturing and installing a reinforcement cage;

G. installing a guide pipe and cleaning holes for the second time;

H. pouring underwater concrete;

I. and taking out the protective sleeve.

Preferably, in the process of impact drilling in the step E, if the slurry surface in the pile hole slowly descends, cracks appear in the pile hole, at the moment, clay is added into the pile hole, the consistency of the slurry is improved, and the drill is continuously punched downwards until the slurry surface in the pile hole returns to normal;

if the liquid level of the slurry in the pile hole drops rapidly to be completely emptied, a karst cave appears on the side surface or below the pile hole, at the moment, the impact drill bit is lifted out, soil-clamping stones are added into the pile hole, the impact drill bit is used for repeatedly impacting and smashing, the soil-clamping stones are squeezed to the karst cave to block the karst cave, the slurry is injected into the pile hole, and the downward impact drilling is continued.

Preferably, if the drill jamming phenomenon occurs in the impact drilling process in the step E, the lower side of the impact drill bit is firstly confirmed, a proper amount of explosive is placed below the lower side, the detonation is carried out until the impact drill bit is lifted, and the downward impact drilling is continued.

Preferably, the anti-turnover mechanism is positioned in a base of the drilling machine, the anti-turnover mechanism comprises a sealed long box body arranged along the length direction of the base, light emitters and light receivers are correspondingly arranged on the inner walls of two ends of the long box body, and the emitting direction of the light emitters is consistent with the length direction of the long box body; water is injected into the long box body, and the water level inside the long box body is slightly lower than the light emitter and the light receiver when the long box body is in a horizontal state; the long box body is also provided with a switch for controlling the winch of the drilling machine and a control chip electrically connected with the optical receiver, and when the optical receiver does not receive the optical signal, the control chip controls the switch to act so as to stop the operation of the winch.

Preferably, the cross section of the long box body is isosceles trapezoid.

Preferably, the protective cylinder comprises a cylinder body and a ring of annular convex ribs arranged at the outer edge of the upper end of the cylinder body; the protective sealing cover consists of two semicircular cover bodies, and each cover body comprises a frame and a protective net arranged in the frame; the centers of the straight edges of the frames are provided with semicircular notches, and the notches on the frames of the two cover bodies form guide holes of the steel ropes together; the lower edge of the arc edge of the frame is provided with a clamping groove matched with the convex edge; the two cover bodies are respectively provided with an ear plate and are mutually connected through bolts penetrating through the ear plates.

Preferably, the casing, the protective cover and the drill bit of the drilling machine are made of alloy materials, and the alloy materials comprise the following components in parts by weight: 120 parts of iron; 8.5 parts of chromium; 20 parts of nickel; 5 parts of silicon; cobalt 2; 0.8 part of iridium; 0.5 part of titanium; 0.5 part of niobium; 0.3 part of scandium; 0.5 part of tellurium; 0.8 part of beryllium; 0.1 part of strontium; 0.8 part of cesium.

Compared with the existing construction method of the punched piles, the construction method of the invention has the advantages that after the pile position is determined, the secondary drilling is carried out on each pile, the drilling depth is at least 5 meters deep into the bearing stratum, so that the engineering personnel can clearly know the real-time geological condition, the bearing stratum at the pile end is determined, and the safety and the reliability of the punched piles are ensured. Meanwhile, the protective sealing cover with a guiding function on the steel rope is adopted, when the hole depth is large, the guide hole in the protective sealing cover is used for guiding and controlling the middle section of the steel rope, and the small error degree between the steel rope and the center of the pile hole is kept, so that the radial runout and the offset of the steel rope are reduced, the deflection quantity of an impact drill bit is effectively controlled, the forming quality of the pile hole is improved, and the risks of accidents such as drill sticking, hole collapse and the like are reduced. In addition, the steel rope can transmit part of force to the protective sealing cover in the process of contacting with the hole wall of the guide hole, then the force is transmitted to the protective cylinder through the protective sealing cover, the force is uniformly dispersed to the surrounding soil through the protective cylinder, and the stress condition of the support arm of the drilling machine is greatly improved. In conclusion, the construction method is particularly suitable for construction of the punched pile under karst geology, can greatly improve the pile forming quality of the punched pile, reduces the incidence rate of accidents such as drill sticking, hole collapse and the like, and prolongs the service life of a drilling machine.

Drawings

FIG. 1 is a schematic view of a rig;

FIG. 2 is a schematic structural diagram of the casing;

FIG. 3 is a schematic view of the protective cover prior to installation;

FIG. 4 is a schematic view of the installed protective cover;

FIG. 5 is a view taken along line A-A of FIG. 4;

FIG. 6 is a schematic structural view of the anti-tip mechanism;

FIG. 7 is a schematic view of the structure shown in FIG. 6 in one use state;

FIG. 8 is a perspective view of the long box;

fig. 9 is a working principle diagram of the anti-overturn mechanism.

Detailed Description

The construction method of the karst geological punching pile comprises the following steps:

A. leveling a construction site through engineering machinery such as a road roller, a loader and the like, and paving a construction access road on the leveled site so as to meet the requirement of walking of the construction machinery; meanwhile, paying off is carried out according to the pile position coordinates given by a design drawing, the position of the punching pile is marked on the site, and positioning is carried out; a mud circulation tank is dug on the field, and the capacity of the mud circulation tank is usually 200m³On the left and right sides, it is needless to say that the size can be reduced or increased as appropriate according to the actual situation.

B. And after the positioning of the punched piles is finished, performing secondary drilling on the geological condition below each pile, wherein the drilling depth is at least 5 meters when the pile enters a bearing stratum, so as to know whether the pile has a karst cave or not, the depth of the karst cave and the like.

C. Burying the pile casing 1 and positioning the drilling machine. Digging a pit at a pile position, installing the pile casing 1 on the pile position, and embedding and tamping the pile casing 1 firmly by using clay and small stones after checking that the pile casing meets the requirements; as shown in fig. 2, an overflow port 2 is arranged at the upper part of the side surface of the casing 1, and during the punching process, slurry can be supplied into the pile hole through the overflow port 2, or excess slurry in the pile hole can be discharged and guided into a slurry circulation pool. The punching and excavation of the punched piles can be carried out only after any other pile within 5m of the distance is poured for 24 hours, so as to avoid interfering the solidification of concrete of adjacent piles; on the basis, multiple machines can simultaneously operate. The installation position of the drilling machine is leveled and tamped in advance, and the machine base 6 is supported by a sleeper; after the drill is in place, the casing 1 can be further compacted by using the percussion bit of the drill. The drilling machine is provided with an anti-overturning mechanism 3, and the anti-overturning mechanism 3 is mainly used for preventing the drilling machine from overturning when the drilling machine is clamped.

The working principle of the anti-overturning mechanism 3 is as follows: when the base 6 of the drilling machine tilts up, a switch is touched, and the winch 10 of the drilling machine is controlled by the switch, for example: referring to fig. 1 and fig. 6-9, the anti-overturn mechanism 3 is located in a base 6 of the drilling machine, the anti-overturn mechanism 3 includes a sealed long box body 7 arranged along the length direction of the base 6, a light emitter 8 and a light receiver 9 are correspondingly arranged on the inner walls of two ends of the long box body 7, and the emitting direction of the light emitter 8 is consistent with the length direction of the long box body 7. The long box body 7 is filled with water, and the water level inside the long box body 7 is slightly lower than the light emitter 8 and the light receiver 9 when the long box body 7 is in a horizontal state. The light emitter 8 and the light receiver 9 are usually selected from an infrared light emitter and an infrared light receiver, and as shown in fig. 6, one of the light emitter 8 and the light receiver 9 is located on the inner surface of the right end of the elongated box body 7, and the other is located on the inner surface of the left end of the elongated box body 7, and the heights of the light emitter 8 and the light receiver are consistent. When the base 6 is in the horizontal state, the box body 7 is also in the horizontal state, and the light emitted by the light emitter 8 can be received by the light receiver 9. As shown in fig. 7, when the base 6 is in the tilted state, the long box 7 is no longer horizontal, and at this time, water inside the long box 7 flows from one end to the other end, that is, the light emitter 8 is submerged, and the light emitted by the light emitter 8 is refracted and cannot be received by the light receiver 9. Similarly, even if the positions of the optical transmitter 8 and the optical receiver 9 are switched, the optical signal cannot be received when the optical receiver 9 is submerged by water.

As shown in fig. 9, the long box 7 is further provided with a switch for controlling the hoisting machine 10 of the drilling machine and a control chip connected with the optical receiver 9 through wires, and when the optical receiver 9 does not receive an optical signal, the control chip controls the switch to operate, so that the hoisting machine 10 stops operating. That is to say, as long as the base 6 inclines, the long box body 7 also inclines, the optical receiver 9 cannot receive an optical signal at the moment, the control chip controls the switch after receiving information feedback, the winch 10 stops running through the switch, the problem that the drilling machine overturns is avoided, and the safety in the construction process is greatly improved. In order to further improve the sensitivity of the anti-overturn mechanism, it is better that the cross section of the long box body 7 is isosceles trapezoid as shown in fig. 8. Thus, since the lower part of the long box 7 has a larger capacity, it is more convenient to ensure that the light emitter 8 or the light receiver 9 is submerged when the long box is inclined.

D. After a drilling machine is in place, performing slurry preparation and percussion drilling links, firstly performing slurry preparation in a slurry circulating pool, wherein the colloid rate of the slurry is not lower than 96%, and the sand content is less than 4%. And at the beginning stage of punching, a certain amount of clay and water are put into the protecting cylinder 1, the clay and the water are slowly flushed, the mud is automatically made by utilizing the impact of an impact drill, then the mud is normally flushed, the mud in the mud circulating pool is injected into the pile hole while the flushing is carried out, and the liquid level of the mud is kept not lower than 0.5m below the top surface of the protecting cylinder 1 all the time. When the depth of a pile hole is more than or equal to 4 meters in the process of percussion drilling, a protective sealing cover 4 is arranged at the upper end of a protective cylinder 1, a guide hole 5 is arranged in the center of the protective sealing cover 4, and a steel rope for hoisting a percussion drill bit penetrates through the guide hole 5. The protective cover 4 has two main functions, namely, on one hand, closing the opening to ensure the safety of constructors, and on the other hand, guiding the steel rope through the guide hole 5 arranged on the protective cover 4.

The specific structure of the protective cover 4 is more, for example, the protective cover 4 is a cover which is in threaded fit with the protective cylinder 1 at the upper end of the protective cylinder 1, and the center of the cover is provided with a guide hole 5, and of course, the protective cover can be in other structures which are convenient to be connected with the protective cylinder 1. However, considering that the construction site is much silt, in order to facilitate the installation and the removal of the protective cover 4, it is better that the casing 1 comprises a cylinder body and a ring-shaped convex rib 11 arranged at the outer edge of the upper end of the cylinder body, as shown in fig. 2 to 5. The protective cover 4 is composed of two semicircular cover bodies 12, the cover bodies 12 include a frame 13 and a protective net 14 arranged in the frame 13, and the frame 13 and the protective net 14 are both made of steel. The center of the straight edge of the frame 13 is provided with a semicircular notch, and the notches on the frames 13 of the two cover bodies 12 form a guide hole 5 of the steel rope together. And the lower edge of the arc edge of the frame 13 is provided with a clamping groove 15 matched with the convex rib 11. The two cover bodies 12 are respectively provided with an ear plate 16, and the two cover bodies 12 are connected with each other through bolts penetrating through the ear plates 16. When in use, the two cover bodies 12 are clamped on the convex ribs 11 at the upper end of the protective cylinder 1, so that the guide holes 5 formed by the two notches wrap the steel ropes. Then the bolt is locked at the ear plate 16, thereby being very convenient to use.

In the process of percussion drilling, the liquid level of the slurry in the pile hole is observed, if the slurry level in the pile hole slowly drops, cracks appear in the pile hole, at the moment, clay is added into the pile hole, the consistency of the slurry is improved, and the percussion drilling is continued downwards until the slurry level in the pile hole returns to normal. If the liquid level of the slurry in the pile hole drops rapidly to be completely emptied, a karst cave appears on the side surface or below the pile hole, at the moment, the impact drill bit is lifted out, soil-clamping stones are added into the pile hole, the impact drill bit is used for repeatedly impacting and smashing, the soil-clamping stones are squeezed to the karst cave to block the karst cave, the slurry is injected into the pile hole, and the downward impact drilling is continued.

If the drill jamming phenomenon occurs in the process of percussion drilling, firstly confirming the lower side of a percussion drill bit, placing a proper amount of explosive below the lower side, detonating until the percussion drill bit is lifted up, and continuing to perform downward percussion drilling. That is to say, when the drill is stuck, the depth of each part of the drill is measured to determine the lower side of the drill, after a proper amount of explosive is wrapped, the explosive is placed below the lower side of the drill along the slotted hole of the drill and then is detonated. The drill is then shaken and lifted out to continue punching.

E. Pore-forming inspection and first pore cleaning: after drilling is completed, the protective sealing cover 4 is taken down, pore-forming is checked, if the pore-forming is qualified, the first pore cleaning is carried out, and if the pore-forming is not qualified, the first pore cleaning is carried out again after adjustment.

F. The manufacturing and installation of the reinforcement cage can be started to manufacture the reinforcement cage after the pore-forming inspection is qualified, and under the karst geology, the pile length can not be determined before the drilling is completed, so that the reinforcement cage with a certain length can be manufactured in advance, the reinforcement cage is lengthened according to actual needs, and then the reinforcement cage is placed into the pile hole through a lifting appliance.

G. Installing a guide pipe and cleaning holes for the second time: and after the reinforcement cage is installed, installing a guide pipe for pouring concrete, and performing secondary hole cleaning after the guide pipe is installed.

H. And (5) pouring underwater concrete.

I. And (3) taking out the pile casing 1, sleeving the rope hoop on the convex edge 11 at the upper end of the pile casing 1 in the process of taking out the pile casing 1, and directly hoisting the pile casing 1 by using a crane or a drilling machine, so that the method is convenient and quick.

Compared with the existing construction method of the punched piles, the construction method of the invention has the advantages that after the pile position is determined, the secondary drilling is carried out on each pile, the drilling depth is at least 5 meters deep into the bearing stratum, so that the engineering personnel can clearly know the real-time geological condition, the bearing stratum at the pile end is determined, and the safety and the reliability of the punched piles are ensured. Meanwhile, the protective sealing cover 4 with a guiding function on the steel rope is adopted, when the hole depth is large, the guide hole 5 on the protective sealing cover 4 is used for guiding and controlling the middle section of the steel rope, the small error degree between the steel rope and the center of the pile hole is kept, the radial runout and the offset of the steel rope are reduced, the deflection amount of the impact drill bit is effectively controlled, the forming quality of the pile hole is improved, and the risks of accidents such as drill sticking, hole collapse and the like are reduced. In addition, the steel rope can transmit a part of force to the protective sealing cover 4 in the process of contacting with the hole wall of the guide hole 5, then the force is transmitted to the protective sleeve 1 through the protective cover 4, the force is uniformly dispersed to the surrounding soil through the protective sleeve 1, and the stress condition of the support arm of the drilling machine is greatly improved. In conclusion, the construction method is particularly suitable for construction of the punched pile under karst geology, can greatly improve the pile forming quality of the punched pile, reduces the incidence rate of accidents such as drill sticking, hole collapse and the like, and prolongs the service life of a drilling machine.

As the protective cylinder 1, the protective sealing cover 4 and the drill bit have higher requirements on the antirust performance in long-term field operation, the protective cylinder, the protective sealing cover and the drill bit of the drilling machine are made of alloy materials, and the alloy materials comprise the following components in parts by weight: 120 parts of iron; 8.5 parts of chromium; 20 parts of nickel; 5 parts of silicon; cobalt 2; 0.8 part of iridium; 0.5 part of titanium; 0.5 part of niobium; 0.3 part of scandium; 0.5 part of tellurium; 0.8 part of beryllium; 0.1 part of strontium; 0.8 part of cesium.

The alloy material is processed and prepared by the following method:

a. smelting iron, chromium, nickel, niobium, scandium, beryllium, tellurium, strontium, cesium and the like according to the weight parts, raising the furnace temperature to maintain 1300 ℃ for smelting for 5 minutes, then raising the furnace temperature, adding titanium, iridium, cobalt and silicon when the furnace temperature is raised to 1800 ℃, and finally smelting all the materials into liquid molten steel.

b. And (3) calming the molten steel prepared by the steps in a smelting furnace for 3 minutes, and then pouring, wherein the pouring temperature is maintained at 1800 ℃, and the pouring is completed within 1 minute and 30 seconds.

c. And after pouring is finished, cooling for more than 3 hours and discharging.

The corrosion resistance result of the alloy material obtained by the steps according to the neutral salt spray test standard of ISO9227 is as follows:

number plate	Chromium content	24h	48h	72h
					The invention	5.3％	√	√	√
304 steel	18.5％	√	√	√

The comprehensive table shows that the protective cylinder 1, the protective sealing cover 4 and the drill bit of the drilling machine which are made of the alloy materials have excellent corrosion resistance, are not easy to rust in the long-term use process, and are particularly suitable for field operation. The chromium content of the alloy is greatly lower than 18-20% of that of the traditional 304 stainless steel, and is less than half of that of the 304 stainless steel, but the corrosion resistance of the alloy reaches the level of the 304 stainless steel. In the traditional understanding, alloy steel with the chromium content of less than 11 percent does not have the antirust performance, but the antirust performance of the alloy reaches a higher level on the basis that the chromium content of the alloy is far lower than the conventional level.

Claims

1. An alloy material for a drill bit, characterized in that: the alloy material comprises the following components in parts by weight: 120 parts of iron; 8.5 parts of chromium; 20 parts of nickel; 5 parts of silicon; cobalt 2; 0.8 part of iridium; 0.5 part of titanium; 0.5 part of niobium; 0.3 part of scandium; 0.5 part of tellurium; 0.8 part of beryllium; 0.1 part of strontium; 0.8 part of cesium;

the alloy material is processed and prepared by the following method:

a. adding iron, chromium, nickel, niobium, scandium, tellurium, beryllium, strontium and cesium into a smelting furnace according to the weight parts, smelting for 5 minutes when the furnace temperature is increased to 1300 ℃, then continuing to increase the furnace temperature, adding titanium, iridium, cobalt and silicon when the furnace temperature is increased to 1800 ℃, and finally smelting all the materials into liquid molten steel;

b. standing the molten steel prepared by smelting in a smelting furnace for 3 minutes, keeping the temperature at 1800 ℃ unchanged, and completing casting within 90 seconds;

c. and after pouring is finished, cooling for at least 3 hours, and discharging.