Guiqiu Road Experiment Internship Report

I searched online and found it out. 1: Introduction to the project. The xx overpass belongs to the second section of the project in front of a certain railway station. The central railway mileage of the bridge is DK112 201, and the intersection mileage with Fuquan Expressway is GK329. The length of the bridge is 415.634m. It is located in a village in Chengxiang District, Putian City. The whole bridge is located on a curve and is composed of 8×32m prestressed reinforced concrete full-hole box girder, 1×24 prestressed reinforced concrete full-hole box girder, 1×32 m cast-in-situ prestressed reinforced concrete full-hole box girder, and 1×80 m steel truss combination. Beam composition.

The box girder is designed as a prestressed concrete single-chamber simply supported box girder. The top width of the box girder is 13.4 meters, the beam length is 32.5m, the mid-span beam height is 2.8m, and the fulcrum beam height is 3.0m. The distance between the cross bridge and the center of the support is 4.7m; the total concrete length of the box girder is 315.2m3. The cast-in-place beam adopts a self-anchored wire drawing system with a standard strength of fpk=1860Mpa. The prestressed pipes are made of corrugated pipes and the anchors are OVM15- 12. There are two types of OVM15-13; prestressed tensioning can only be carried out when the concrete strength reaches 100; tensioning is carried out according to the sequence of steel tendon numbers. The tensioning is controlled by both stress and elongation, with stress as the main factor and tension as the main factor. After the pulling is completed, use No. 40 cement slurry to grout.

Two: Gains and Experiences First of all, internship is a familiar and unfamiliar word to me, but this time because I have experienced a lot in my ten (Xuezi.com-Internship Report) student career The internship is so different. He will comprehensively test my abilities in all aspects: study, life, psychology, body, mind, etc. It is like a touchstone to test whether I can apply the theoretical knowledge I have learned into practice. It is related to whether I can successfully establish myself in this challenging society in the future, and it is also the key to building my confidence. Therefore, my investment in it is 100%! The intense internship life of more than one month is over. I still have a lot of gains in this more than one month. It is necessary to summarize it after the internship. First of all, through more than a month of internship, I learned a lot of practical knowledge through practice. The so-called practice is the only criterion for testing truth. By standing on the sidelines, I observed the entire house construction process at close range and learned a lot of practical and specific construction knowledge. This knowledge is often something I rarely come into contact with in school. Note, but it is very important basic knowledge. For example, let me talk about the construction of bored piles, so let me talk about what I have learned:

1. Process principle

Bored piles are drilled into piles by drilling machines. Select the type of drilling rig according to different soil types. In order to ensure the quality of drilling, the performance indicators of the mud must be frequently tested during the process to prevent hole collapse. After the hole is inspected and passed the inspection, the steel cage that has been made is installed and fixed firmly at the hole opening, and then the conduit is installed to pour underwater concrete and tested after installation.

2. Operation characteristics and construction conditions

Construction machines and tools are relatively complex. If it occupies a large space, you should choose a mud pool. The construction process must be strictly controlled to prevent collapsed holes and broken piles. The construction conditions require a mud pool to be selected in a suitable place nearby, with water, electricity and access roads required, and the site must be flat and dense.

3. Construction technology and precautions

(1) Construction technology

1. Preparation work

(1) Site layout and Smoothness: The construction site is relatively flat, a little flatness is enough.

(2) Pile position measurement: After the site is ready, the positioning can be measured, and the center of each pile position can be accurately marked with long wooden piles and iron nails.

(3) Buried casing: The casing is made of steel casing, rolled with 3mm thick steel plate. When using a percussion drill, the inner diameter of the casing is 40cm larger than the design diameter. Weld a reinforcement, the top of the casing is 30cm above the ground, ram the clay around, and bury the deviation ≤ 5.0cm

2. Drilling

(1) Drilling rig in place

First assemble the drilling rig and install the lifting system, move it into position with the deviation not greater than 5.0cm, then lift the drill bit and slowly put it into the casing. Before the drilling rig is put in place, the main machinery and tools are inspected, repaired and installed, supporting facilities are put in place and water and electricity supply are connected.

(2) Before drilling, draw a geological profile of the hole location based on the geological and hydrological data provided in the construction drawing design, and hang it on the drill floor so that appropriate drill bits can be selected for different soil layers. Reference data such as feed pressure and speed and suitable mud. During drilling, always pay attention to the changes in the soil layer, take ballast samples wherever the soil layer changes, judge the soil layer, record it in the record table, and check with the geological profile to see if it meets the design bearing capacity.

(3) After the drilling rig is installed in place, the base and top should be stable and free of displacement and tilt.

(4) Drilling operations must be carried out continuously without interruption. When drilling must be stopped due to objective reasons, the hole opening should be covered with a protective cover, and the drill cone must not be left in the hole to prevent the drill from being buried.

(5) During drilling, attention should be paid to promptly removing drilling debris and maintaining mud consistency and viscosity to avoid buried drilling caused by muddy drilling and hole collapse.

(6) Drilling operation requirements; when starting drilling, the footage should be controlled appropriately, and a small stroke should be used to open the hole, so that the initial hole can be vertical and round, can serve as a guide, and prevent the hole from being eccentric , orifice collapse. If encountering rock formations, a medium to large stroke of 4 to 5m can be used, but the maximum stroke shall not exceed 6.0m. Remove drilling debris in time during drilling.

3. Hole cleaning

The purpose of hole cleaning is to replace the mud in the hole, remove the sedimentation layer of drill ballast, minimize the thickness of sedimentation at the bottom of the hole, and prevent excessive sedimentation soil from remaining at the bottom of the hole. And reduce the bearing capacity of the pile. Secondly, hole cleaning also creates good conditions for pouring underwater concrete, and the pouring is smooth. The hole cleaning method adopts the cyclic slurry cleaning method.

4. Preparation and hoisting of the steel cage into place

(1) The steel cage is installed on site, and its frame must have sufficient stiffness and stability to avoid damage during hoisting and pouring of concrete. Loose, displaced, deformed.

(2) In order to ensure that the steel cage does not rely on the hole wall when it is placed in the manhole and has a sufficient protective layer, four "reinforcement earrings" are symmetrically installed on the main bars of the steel cage every 2m or so.

(3) The steel cage is lifted into place at one time. Before entering the hole, pay attention to check whether there is any collapse hole after the final hole, so that timely measures can be taken to ensure that the steel cage can be placed smoothly.

(4) When hoisting the steel cage into the cage, it should be placed gently at the center of the hole. After it is in place, it should be firmly positioned. The fixed facilities can only be released after the initial setting of the concrete pouring.

5. Set up the conduit

Before hoisting the conduit, the conduit should be assembled and tested. The connection should be firm, the sealing should be tight, and the top and bottom should be in a straight line. When hoisting, it should be located in the center of the well hole and should be in the center of the well. Conduct a lifting test before pouring concrete.

6. Pouring underwater concrete

(1) Pouring concrete is an important process in bored pile construction. Before pouring, the thickness of mud sedimentation at the bottom of the hole should be detected. If it is greater than the design thickness (≤5cm), clean the hole again until the requirements are met.

(2) When the concrete mixture is transported to the pouring site, the workability, slump, etc. should be checked. If it does not meet the requirements, the concrete will be mixed a second time until it meets the usage requirements.

(3) When pouring the first batch of concrete, attention should be paid to: a. The distance from the lower opening of the conduit to the bottom of the hole should generally be 25 to 40cm; b. The depth of concrete poured into the conduit shall not be less than 1.0m; c . After the concrete is poured into the bottom of the hole, immediately detect the height of the concrete surface in the hole and calculate the buried depth of the conduit. If it meets the requirements (Xuezinet-Internship Report/baogao/shixibaogao), proceed with normal pouring.

(4) After pouring begins, proceed continuously and rhythmically to shorten the interval between removing the conduit as much as possible; when the concrete in the conduit is not full, pour slowly to prevent high-pressure air pockets in the conduit. Leaking catheter.

(5) During the pouring process, the water head of the well hole should be maintained at all times to prevent hole collapse, and the depth of the conduit outlet inserted into the concrete should be maintained at least 1.0m.

(6) When the concrete surface of the well hole is close to the steel frame, keep the conduit at a slightly larger depth and slow down the pouring speed; when the concrete surface of the well hole enters the steel frame to a certain depth, lift the conduit appropriately , so that the steel frame has a certain burial depth at the lower opening of the conduit. (The steel cage here fully extends into the bottom of the hole)

(7) In order to ensure the quality of the pile top, pre-cast 1.0 to 1.5m above the design elevation of the pile.

(8) Near the end of pouring, the height of the concrete column in the conduit is relatively reduced and the overpressure is reduced, while the consistency and specific gravity of the mud and contained soil outside the conduit increase, and when the concrete is jacked up In case of difficulty, water can be added to the hole to dilute the mud and part of the precipitated soil can be taken out to make the pouring work go smoothly.

(9) When pouring concrete, no less than 6 groups (3 pieces) of concrete specimens should be made for each pile.

(10) When pulling out and lifting the casing, attention should be paid to: the integral rigid casing at the wellhead located below the ground and pile top should be pulled out immediately after pouring concrete.

(2) Precautions

1. In order to prevent the impact vibration from causing the wall of the adjacent hole to collapse and affecting the solidification of the concrete that has just been poured in the adjacent hole, the concrete in the adjacent hole should be poured after the pouring is completed. Generally, Drilling can be started after 24 hours.

2. If water loss is found and the water level in the casing drops slowly, water should be replenished and clay added. When opening a hole, in order to squeeze the drilling mud into the hole wall as much as possible, ballast is generally not pumped out. After 4 to 5m, the ballast can be removed. Pay attention at all times during drilling to keep the hole position correct.

4. When drilling, observe the rebound and rotation of the wire rope, and listen to the impact sound to judge the situation at the bottom of the hole. It is necessary to master the principle of loosening the rope less. Loosen the rope too much and it will reduce the stroke. Loosen the rope too loose and loose too little, it will be like a missing hammer and damage the machine. When there are many rocks in the soft ground, generally loosen the rope 3 to 5 cm at a time and make the ground evenly dense by 5 to 8 cm.

5. During the impact process, ballast should be removed frequently and the wear and damage of the wire rope and drill bit should be checked frequently to prevent safety and quality accidents.

6. The wear of drill bit diameter should not exceed 1.5cm, and it should be checked frequently and repaired with wear-resistant strips in time. And always keep two drill bits for rotational use and repair. In order to prevent the drill from getting stuck, it is not advisable to do too much repair welding at one time, and when using it in the original hole after repair welding, it is better to impact with a low stroke for a period of time before drilling with a higher stroke.

7. When the ballast content of the mud in the hole increases, the drilling speed slows down, the pebble layer is less than 5 to 10cm per hour, and the soft soil layer is less than 15 to 30cm, ballast extraction should be carried out. Generally, ballast is pumped once every 0.5 to 1.0m of footage. Each time, the ballast in the mud is significantly reduced, there are no coarse particles, and the specific gravity drops to normal. When pumping out ballast, you should pay attention to the following:

(1) Add grout or water to the hole in time. If you are adding clay to make slurry by yourself, it is not advisable to pour it in all at once to prevent the drill from sticking.

(2) Use the sedimentation tank method to flow the settled mud into the mud tank, and then use a mud pump to pump it back into the hole.

8. In order to ensure the integrity of the hole shape, a hole detector should be commonly used during drilling. The hole detector is made of steel bars. Its height is 4 to 6 times the diameter of the drill hole, and the diameter is the same as that of the drill bit. The diameter is the same.

Before replacing the drill bit, the hole must be inspected and the new drill bit can be put in after the hole inspection is reached to the bottom of the hole. If the hole detector cannot sink to the original drilled depth, or the position of the wire rope (when tightened) deviates from the center of the casing, consider that bent holes, inclined holes or shrinkage holes may have occurred, and remedial measures should be taken in time. measure.

9. In order to control the specific gravity of the mud and the frequency of ballast pumping, a sampling tank must be placed at the required depth to take out the mud for inspection, and mud must be poured into the hole or clay should be crushed in a timely manner. For impact drilling, the proportion of mud at the bottom of the hole is preferably 1.4 to 1.6.

4. Quality requirements

(1) Materials

1. Cement

(1) The cement used for mixing concrete is made of A supplies bulk cement.

(2) The transportation, storage and use of cement should comply with relevant regulations.

2. Fine Orthopedics

(1) The fine aggregate should be natural sand with a particle size of less than 5mm.

(2) The contents of harmful impurities are within the specification limits.

(3) The content of particles larger than 5mm shall not exceed 5%.

(4) The material and usage requirements of fine aggregate should be implemented in accordance with relevant regulations.

(5) Each batch of fine aggregate should have a material test certificate and be submitted to the supervision engineer for approval before use.

3. Coarse aggregate

(1) Coarse aggregate is made of hard and durable gravel. It is prohibited to use limestone gravel that is corroded by mineral water, especially acid water, or that has been severely burned. of stone (dolomite or limestone). Coarse aggregates should be inspected in batches according to different conditions such as origin, category, processing method and specifications.

(2) The particle gradation of coarse aggregate should be continuous graded gravel (Xuezinet-Internship Report/baogao/shixibaogao) or continuous grading and single-grain grading should be used together.

(3) The content of harmful impurities in coarse aggregate shall not exceed relevant regulations.

(4) The material and use of coarse aggregate shall be in accordance with relevant regulations.

(5) Each batch of coarse aggregate should have a material test certificate and must be approved by the supervision engineer before it can be used.

4. Mixing water

In addition to complying with current regulations, the water used for mixing concrete should also comply with the following regulations:

(1) Used The water must be tested and approved by the supervising engineer.

(2) The water should not contain harmful impurities or grease, sugar, etc. that affect the normal setting and hardening of cement.

(3) Sewage, acidic water with a pH value less than 4, and water containing sulfate content (calculated as SO42-) exceeding a water weight of 1 shall not be used.

(4) Drinking water that meets the national standard "Hygienic Standards for Drinking Water" can be used for mixing.

5. Admixtures

(1) All kinds of concrete admixtures must be produced by specialized manufacturers that have passed measurement certification and must have factory inspection certificates. , indicate the name, use, effective substance content, recommended dosage, usage precautions and other explanatory information, and submit it to the supervision engineer for approval.

(2) The technical requirements for concrete admixtures must not only comply with the "Technical Specifications for the Application of Admixtures" of the People's Republic of China and the National Standard, but also must comply with relevant regulations.

(3) The dosage of admixtures should be verified by laboratory tests.

(4) When using aqueous solution retarder in the mixing department, its water content should be included in the effective water consumption of the mixture.

6. Steel bars

(1) Each batch of steel bars should have the manufacturer’s factory inspection certificate, mechanical properties and chemical composition test report form, and its marked indicators, Data batches, descriptions, and visa stamps should be complete, accurate, and authentic.

(2) Steel bars must be inspected and accepted in batches according to different steel materials, grades, brands, specifications and manufacturers, stored separately, and must not be mixed. Sufficient signs must be set up to facilitate inspection and use. Transportation and transportation of steel bars. Loading and unloading shall be handled in accordance with relevant regulations.

(2) Orifice guard

1. Diameter: impact drill diameter D+40 (cm).

2. Tube top elevation: 0.3m higher than the construction ground.

3. The burial depth of the casing: the clay on the beach should not be less than 1.0m; the sandy soil should not be less than 2.0m; the soft soil layer should be buried in a solid layer of not less than 0.5m.

(3) Wall protection mud

1. The raw material of mud should be high-quality clay.

2. Mud proportion: When the impact drill uses a solid drill bit to drill holes, the mud proportion at the bottom of the hole should not be greater than: 1.3 for sand and clay, 1.4 for large boulders and pebbles, and 1.2 for rock.

3. Mud viscosity: 16~22S for general strata; 19~28S for loose and prone to collapse strata.

4. The sand content of the mud is ≯4.

5. The top surface of the mud inside the casing should always be at least 1m higher than the water level or groundwater level outside the casing.

(4) Drilling

1. When impact drilling, drilling can only be started after the concrete pouring in the adjacent holes is completed and the compressive strength of 2.5Mpa is reached.

2. Drilling of pile holes should be done continuously in shifts and should not be stopped midway.

3. After drilling reaches the designed depth, the hole position, hole diameter, hole depth and hole shape should be checked.

4. The bottom of the hole must be inspected and signed by the supervision engineer before the work of hoisting the steel frame and pouring concrete can be carried out.

(5) Clearing holes and placing steel cages

Table of allowable deviations of bored pile steel skeletons

Table 1

Serial number items Allowable deviation inspection method

1 Inspection of steel frame length ±100 feet

2 Inspection of steel frame diameter ±20 feet

3 Main bar spacing ±0.5d feet Measurement inspection

4 Stiffener spacing ±20 feet inspection

5 Stirrup spacing ±20 feet inspection

6 Steel frame verticality 1L hanging wire and ruler Measurement check

Note: d is the diameter of the main bar, and L is the length of the skeleton.

1. Clear the holes

The holes should be cleared before pouring underwater concrete. The allowable ballast thickness of the column piles shall not exceed 10cm. When clearing the hole, the water level in the borehole should be kept 1.5 to 2.0m higher than the groundwater level to prevent hole collapse. Methods of deepening the depth of the hole bottom should not be used instead of clearing the hole.

2. Reinforcement cage

(1) The main bars and reinforcing steel bars must all be welded to increase the stiffness of the steel cage.

(2) The steel cage should be firmly positioned after the manhole to prevent cage falling and floating cage accidents.

(3) The allowable deviation of the steel frame should comply with the provisions of Table 1 below.

(6) Injecting underwater concrete (conduit method)

1. Gravel should be preferred as the coarse aggregate for underwater concrete, and its maximum particle size should not be greater than 1/2 of the inner diameter of the conduit. 6~1/8 and 1/4 of the minimum clear distance of steel bars, and the gravel should not be larger than 30mm.

2. The concrete slump should be 180mm~220mm.

3. The initial amount of concrete should be enough to ensure that the depth of the conduit buried in the concrete is not less than 1m after the first batch of concrete is put into the hole.

The depth of concrete introduced during pouring should be maintained between 2 and 4m, and shall not be less than 1.0m under any circumstances to avoid pile breaking accidents. Underwater concrete should be poured continuously without stopping midway.

4. The amount of concrete poured should be recorded and measured at any time to record the depth of embedment of the conduit and the surface height of the concrete.

5. The top surface of underwater concrete pouring should be 0.5~0.8m higher than the designed pile top to facilitate the removal of floating slurry, but the removal operation should prevent damage to the pile body.

Permissible deviation of bored pile position and allowable thickness of pile bottom ballast

Table 2

Permissible deviation of serial number items (mm) Inspection method

1 Pile position deviation 100 measurement and inspection

2 Ballast thickness 100 measurement and inspection

3 Pile position inclination 1% hole depth measurement and inspection

6. There should be no less than 6 groups (3 pieces) of concrete specimens taken from each pile.

(7) Quality standards

1. Actual measurement items

See Table 2 for the allowable deviations and inspection methods of bored piles.

2. Appearance identification

(1) After the reserved part of the pile head is chiseled away, there should be no residual loose layer and weak concrete layer.

(2) The length of the concrete pile heads and anchoring steel bars that need to be embedded in the cap should comply with the drawing requirements. If the anchoring length is lower than the minimum anchoring length required by the specification, it must be reworked

5. Prevention and treatment of drilling accidents

(1) Hole collapse

The collapse of the hole entrance is easy to find, while the collapse inside the hole requires careful observation. If the water level in the hole suddenly Decline, fine blisters appear on the surface of the hole mouth; the amount of unearthed material increases significantly, and there is no or very small footage; the depth of the hole suddenly becomes shallow, the drill bit cannot reach the original hole depth, and the load of the drill rig increases significantly, etc., all indicate that the hole has collapsed .

1. Causes of hole collapse

(1) The specific gravity or viscosity of the mud is too small and a solid protective wall is not formed.

(2) The quality of rammed soil at the construction site is poor.

(3) The drilling rig and drilling frame are not well supported, and the supporting surface is subject to excessive pressure.

(4) The casing is buried too shallowly.

(5) The embedded casing does not meet the requirements, and the surrounding or bottom of the casing is not compacted and filled with high-quality clay in layers.

(6) When opening the hole, no wall construction has been done within the 2 to 3m range at the foot of the casing.

(7) The diameter of the casing is too small or the casing is not buried straight and vertically. When opening a hole, the drill bit shakes left and right to impact the casing, and the drill bit collides with the casing during drilling.

(8) The specified water level in the hole is not high enough or the specified water level is not maintained.

(9) The height of the casing is not enough, and pressurized water gushes out of the hole, reducing the static pressure of the water.

(10) Cutting too fast in soft sand.

(11) When lifting the drill bit to drill, the speed is too fast.

(12) Failure to take timely measures when encountering quicksand layers prone to collapse.

(13) Improper hole cleaning method.

(14) The water flow collapses the hole wall when replenishing water.

(15) The drill bit or steel cage collides with the hole wall.

(16) The amount of water supply is too large, which often overflows the hole and soaks the soil at the hole, causing it to become soft and collapse.

(17) There is too long delay from the final hole to the pouring of underwater concrete.

2. Prevention and treatment of hole collapse

(1) When drilling in loose silt soil, silt layer or quicksand, the footage should be controlled and a drill with a larger specific gravity should be used. High-quality mud with high viscosity and colloid ratio (or put in clay and flakes and impact with a low hammer to squeeze the clay paste, flakes, etc. into the hole wall).

(2) If the hole mouth collapses, it can be backfilled and re-buried with a casing before drilling. Or lower the steel casing to at least 1.0m below the uncollapsed point.

(3) If the collapse in the hole is not serious, increase the mud weight and continue drilling. In more serious cases, the sand, gravel and clay mixture can be backfilled to 1 to 2m above the collapse location, or even the entire area can be backfilled before drilling. If the drill bit collapses and is buried, clean the hole first and then lift the drill bit.

(4) Strictly control the stroke height.

(2) Slurry leakage in boreholes

In strata with strong water permeability or groundwater flow, slurry will leak out of the hole. Generally, there will be slurry leakage at the bottom of the casing and protection tube. There are two situations of grout leakage at barrel joints. Serious grout leakage is a precursor to hole collapse and should be dealt with in time. The main reasons for grout leakage are: the casing is buried too shallowly, the backfill soil is not dense or the casing joints are not tight, or the water head is too high, etc. The remedy is to thicken mud or backfill soil and mix it with eggs and rubble to increase the protective wall. If the casing itself leaks, it can be plugged with cotton wool. In addition, falling objects in the casing can also cause slurry leakage.

(3) Curved holes

During drilling, curved holes are produced due to the deflection of the drilling direction, which seriously affects the installation of the steel cage and the quality of the piles.

1. Reasons for bent holes

(1) The drilling rig is located on soil layers with different softness and hardness, and displacement and subsidence occur during drilling.

(2) When drilling, encounter large boulders, probe rocks or inclined rock formations.

(3) Drilling at the junction of sloping soft and hard strata, where the rock surface is inclined; or drilling in sand and gravel layers with widely different particle sizes, the drill bit will experience uneven resistance.

2. Treatment method

When the bent hole is not serious, the drilling rig can be readjusted to continue drilling. In severe cases, the drill hole should be backfilled with sand and clay, and the percussion drill hole should be backfilled with clay mixed with sand, pebbles or small stones to 0.5m above the curved hole, and then drilled after sedimentation or compaction with low-stroke impact. Do not use an impact drill to repair the hole directly to avoid the drill getting stuck.

(4) Paste drilling

When percussion drilling, the stroke can be reduced, the mud schedule can be reduced, and part of the sand and gravel can be backfilled on the clay layer to prevent the impact drill bit from being absorbed.

(5) Shrinkage cavities

Plastic soil (commonly known as rubber) is sandwiched in the stratum, which expands when exposed to water, causing the pore diameter to shrink. Or the drill bit is seriously worn and is not repaired in time, resulting in a hole smaller than the designed pile diameter. When encountering this situation, you can use the method of repeatedly sweeping the hole up and down to expand, or backfill with sand and clay, and drill again after it is dense.

(6) Plum Blossom Holes

Plum Blossom Holes or Probe Stones (that is, the hole shape is not round and some of the hole walls are protruding) are accidents often encountered in impact drilling. The reasons are: The mud is too thick, hindering the rotation of the drill bit; the steering device fails, and the drill bit always impacts up and down in one direction; the wire rope is too loose during operation, or the stroke is too low, and the drill bit does not get sufficient turning time, so it is easy to form plum blossom holes in the bedrock. Probe stones are prone to appear in heterogeneous strata such as drift, pebble, and accumulation layers. When the above situation occurs, it is generally necessary to backfill and re-drill with gravel or rubble that is stronger than the bedrock or probe stone.

(7) Drill stuck

The drill bit is stuck at a certain height from the bottom of the hole and cannot be lifted up, but it can be moved downwards to become stuck. If it is stuck at the bottom of the hole and cannot move, it is stuck.

1. The reasons for drill sticking are:

(1) The irregular hole shape has not been processed.

(2) The hole collapsed and rocks fell, and tools fell into the hole.

(3) The long casing is tilted, and the lower end is deformed by the impact of the drill bit.

(4) The drill bits are of different sizes, or the welding repair exceeds the limit.

(5) Drilling down too hard will cause the drill bit to collide and tip over in the hole.

If a stuck drill occurs, it is not advisable to lift it by force, and do not move it blindly to avoid getting stuck and getting tighter, or causing the hole to collapse and bury the drill.

2. Treatment method

(1) Lift the drill bit up and down to rotate it, and use a crowbar to cooperate, and repeatedly move the rope left and right so that the drill bit can fall along the original path. propose.

(2) Use a small drill bit to impact the stuck hole wall or drill bit on one side to loosen the drill bit before lifting.

(3) First detect the location of the obstacle, tighten the drill bit rope, and use punching and suction methods to loosen the stuck drill bit and then lift it out.

(4) When there is no room for movement, the forced formulation method can be used. The position of the forcibly lifted supporting sleeper stack should be slightly away from the hole range to prevent the hole from collapsing, and a safety rope should be added to prevent the big rope from breaking and the drill falling out. Specifically, pulleys, levers, jacks and other methods can be used to exert force to pull out the drill bit.

During the treatment process, the mud must continue to be stirred to prevent sedimentation and burial of the drill.

(8) Diamonds fall out

1. Reasons for diamonds falling out

(1) Forced lifting and twisting when the drill is stuck.

(2) The welding quality of the alloy sleeve of the impact drill bit is poor, and the wire rope is pulled out.

(3) At the connection between the wire rope and the drill bit, the number of rope clamps on the wire rope is insufficient or loose.

(4) Most of the wire ropes were broken and were not replaced in time.

2. Salvage method

After the drill bit is dropped, the situation should be found out in time, such as the depth of the hole, whether the drill bit is deflected, whether there is a collapsed hole, etc. If the drill bit is buried, it should be First, clear the hole so that the fishing tool can contact the drill bit. The following methods are generally used for fishing.

(1) Fishing fork method: When the impact drill bit wire rope is broken or the wire rope is stuck loose, and no less than 2m of wire rope is left on the drill bit, a fork-type fishing needle can be used to lift up and down in the hole. Clamp the short wire rope and lift out the drill bit.

(2) Hook extraction method: Reinforcement rings or salvaged beams are pre-welded on the drill head, and hooks can be used to hook it.

(3) Rope roping method: Put a single rope sling (or double rope sling) on ??the top of the impact drill. When there is difficulty, the guide ring with a lasso can be fixed on a stiff rod or the lower end of the ballast drum, and sent to a pre-explored position. The top of the drill can be lassoed, and the lasso can be tightened to take it out. .

When stray objects or tools fall into the hole, electromagnets can be used to absorb them.