Bored Piling Works
This video visually explains the sequences of the Bored Piling Works from start to end; The Setting-out of piles, Pre-boring, Steel casing installation, Soil boring, Confirmation of SPT level, Confirmation of Rock level, Rock coring, Confirmation of Toe level, Test on Bentonite slurry, Pile reinforcement cage inspection, Lowering of pile reinforcement cages into the bored pile, Lapping with U-clips, Spacers, Installation of tremie pipes until toe level, Test on fresh concrete, Reconfirmation of Toe level, the Concrete casting of the pile, Flushing-out of concrete, Removal of the steel casing.
Bored piles, also known as replacement piles, are a commonly-used form of building the foundation that provides support for structures, transferring their load to layers of soil or rock that have sufficient bearing capacity and suitable settlement characteristics.
Bored piles are piles where the removal of soil forms a hole for a reinforced concrete pile which is poured in situ. The soil is replaced by the pile, hence 'replacement' piles as opposed to displacement piles where the soil is forced away by driving or screwing the pile.
Bored piles are used primarily in cohesive subsoils for the formation of friction piles and when forming pile foundations close to existing buildings. They are popular in urban areas as there is minimal vibration, where headroom is limited, where there is no risk of heave, and if there is a need to vary the length of the piles.
Installation
Bored piles are drilled using buckets and/or augers driven by percussion boring (vibratory hammers) or through the rotary boring (twisting in place).
In unstable soil strata, the use of bentonite fluid assists in stabilizing the bore especially in large diameter deeper piles and allows the insertion of heavily reinforcing steel cages. This is known as flush boring (see more below).
If the boring and pouring take place simultaneously, piles are known as continuous flight auger (CFA) piles.
Piles are known as large diameter piles if they are 600 mm or more in diameter. Small diameter piles of less than 600 mm are sometimes placed in groups under a common pile cap to receive heavy loads.
Large diameter piles can have their bearing capacity increased by under-reaming the shaft at the base. This is achieved by an expanding cutting tool that cuts a conical-shaped base up to three times the diameter of the main shaft.
The form of support to the pile or borehole affects the pile formation. Bored piles can be either supported or unsupported.
Unsupported piles
Where piling is undertaken in stable soils it may be possible to bore and place the concrete without first lining the hole. However, precautions need to be taken by lining the first meter of the hole to prevent surface soil from falling into the hole.
Supported piles
There are two categories of supported pile depending on the casing or lining that is used.
Permanent casing
The borehole can be formed by the percussion method which involves a heavy cutting tool on a small tripod that is dropped from its raised position using a winch to cut out a cylinder of earth. The operation is repeated until the hole has been sunk to the required depth. As the cutting proceeds, a thin sectional lining is inserted into the hole to prevent its collapse. Alternatively, the borehole can be formed by the rotary method in which the rotary drill operates within the casing or lining.
Temporary casing
It is common for the borehole to be supported by a screw-jointed steel lining which is removed either during or after the concrete has been placed. The tube can be winched or jacked out of the ground.
Flush boring uses a fluid such as a bentonite to flush material from the hole, which has been loosened by drilling. The fluid can be poured from above (reverse flushing) or pumped through the drilling rod (direct flushing). The bored hole is lined with a temporary steel casing to prevent the collapse of loose surface soil. As the boring proceeds, bentonite is continuously fed into the hole.
At the required depth, reinforcement is lowered through the bentonite and concrete poured. The bentonite is displaced by the concrete and pumped back up out of the hole. As the concrete reaches the hole’s upper level, the temporary casing is withdrawn.
Пікірлер: 48
Its a complete video explaining scratch from setting out to concreting of Bored cast in-situ Piling. For any person, who doesn't even know about piling also will understand clearly. Thanks for posting
@ProudtobeaCivilEngineer
2 жыл бұрын
Thank you for your valuable comments. Hope this video is much helpful for fresh graduates as well as for any person who doesn't know about bored piling works.
Your the best Thank you So educative video
Most detailed video about piling. Thanks 👍
@ProudtobeaCivilEngineer
2 ай бұрын
Glad you liked it
Love it from the Start to the End of this Video. I Learned many from it. Please accept my deepest Thanks.
@ProudtobeaCivilEngineer
9 ай бұрын
Glad you liked it! Thank you so much for your compliments!!!
Should still be checking the offsets on the auger flights till at least the top of auger.start of true and sets it up for rest of the pile.
Thank you so much , This video is very informative for me.
@ProudtobeaCivilEngineer
Жыл бұрын
Thank you so much for your kind words
Very informative and educative. Thank you
@ProudtobeaCivilEngineer
Жыл бұрын
Thank you for watching. Kindly recommend our channel if possible.
I appreciate your efforts ❤
@ProudtobeaCivilEngineer
Жыл бұрын
Thank you so much 😀
Very educative Thank you
@ProudtobeaCivilEngineer
Жыл бұрын
Thank you
very use full
@ProudtobeaCivilEngineer
Жыл бұрын
Thank you
Tnx
@ProudtobeaCivilEngineer
Жыл бұрын
Thanks for watching
I dont understand the last part where they partially lift the casing for top up concrete. I thought its build up for pda but it collapse after they pulled out the whole casing. Great video though, thanks. But, somebody explain the last part pls. Thanks.
@ProudtobeaCivilEngineer
3 ай бұрын
Thanks for watching the video. I'm happy to see that you asked a great question. Sometimes, the cut-off level is much deeper compared to near-surface. The sound concrete must be above the cut-off level for the bored piles. The pile cross-section is perfectly circular in drawings, but it's not in reality. This depends on the soil profiles as well as the verticality of the boring rig. Therefore, there are variations in the concrete quantities theoretically and actually. So, in order to ensure that the sound concrete is above the cut-off level, we usually top up the concrete at the end. That's why we lift the steel casing (ensuring that the required length is embedded below the ground) and pour the concrete into the casing. At the end, we remove the steel casing, as it is temporary. I hope this explanation answers your question.
@dexteranislag1266
3 ай бұрын
Okay I get it now. Thank you for sharing 👍🏿
What preventive method should we done if raining during boring of hole and during conreting of bored hole,and is there any effect if the bentonite mix with rain?
👍👍
@ProudtobeaCivilEngineer
2 жыл бұрын
Thank you
How long does it take to finish the construction of one bored pile from setting out to concrete pouring?
If the cleaning bucket cant completely clean the bottom of the bore hole,the other method will be air lifting only?
@desmondtan7807
Ай бұрын
Hi,any answer?
ayuuuuuun...
Thanks for the video. May I ask why does the reo cage welded to the casing? Is it because the bore is deeper than required?
@ProudtobeaCivilEngineer
2 жыл бұрын
Hi Ahmed Jameel, Referring to this video, The pile is Tension pile. So that the Rebar cage must be provided from the Toe of the pile. However, the Cut-Off_Level is 2m below the existing ground level. Due to the concrete pouring in a confined space, the rebar may have possibilities to move upwards slightly. So in order to control the slight upward movement, we are welding the rebar cage with casing.
@ahmedjameel4578
2 жыл бұрын
@@ProudtobeaCivilEngineer thanks man
Can i ask when to do the test for bentonite slurry,is it before concreting?or after boring hole work done ?or before boring of the hole?
@ProudtobeaCivilEngineer
Ай бұрын
Thank you for watching our videos. In bored piling works, checking the bentonite slurry is a critical process to ensure the stability of the borehole and the quality of the final pile. Here are the key times when bentonite slurry should be checked: 1) Before pumping into the boredhole: Density: Ensure the density of the bentonite slurry meets the required specifications. Typically, the density should be around 1.03 to 1.10 g/cm³. Viscosity: Check the viscosity using a Marsh funnel. The viscosity should usually be between 28 to 40 seconds for a 1000 ml flow. pH Level: The pH should be between 8.5 and 10.5 to ensure the bentonite is active and will perform effectively. 2) During boring operation: Density and Viscosity: Regularly monitor the density and viscosity of the slurry during the drilling process to ensure consistency and to avoid sedimentation. Sand Content: Check the sand content regularly (typically it should be less than 4%) to prevent excessive wear on the drilling equipment and ensure the slurry can support the borehole walls. 3) Before Concrete Placement: Cleanliness: Ensure the bentonite slurry is clean and free from excessive sand and debris. This may involve desanding operations. Filtrate Loss: Check the filtrate loss of the slurry. This is important to ensure that the slurry does not dehydrate the soil excessively, which could destabilize the borehole walls. Density and Viscosity: Recheck the density and viscosity to ensure they are within the acceptable range for concreting. 4) After Concreting: Displacement Check: Ensure that the bentonite slurry is properly displaced by concrete during the pouring process. Monitor the return slurry for contamination and ensure it is properly disposed of or recycled. Consistent and careful monitoring of the bentonite slurry at these stages helps in maintaining the integrity of the borehole and ensures the successful installation of the pile. Feel free to ask questions! Thanks again. Kindly suggest our content to your friends and colleagues.
@desmondtan7807
Ай бұрын
What if the sand content or other viscosity too high?what can we done?air lifting will settle this issue?
47:14 What is the reason ?
@ProudtobeaCivilEngineer
3 ай бұрын
The vermiculate granules were poured into the pipe, to act as a separator in between the bentonite and the fresh concrete. This is to avoid the contamination of concrete with bentonite.
What is the purpose of the bentonite slurry?
@ProudtobeaCivilEngineer
Жыл бұрын
Bored piling works are related to soil profiles. Soft soils have a tendency to collapse during pile boring works. In order to overcome this issues, the stabilizing liquids are used. Bentonite slurry is one of the Stabilizing Liquids.
@jaynardmagbanua6595
Жыл бұрын
Ooooo..... So you mean it coats the surface of the bored soil so that it will be stiffer?
@ProudtobeaCivilEngineer
Жыл бұрын
@@jaynardmagbanua6595 yeah,
Good job👍 SMSCC DRILLING TOOL is a China based leading drilling tools manufacturer, has been specialized in bored piling drills nearly 10 years. I hope we could establish cooperation relationship with your company, thanks for your attention.🤝
@ProudtobeaCivilEngineer
Жыл бұрын
Thanks for the info!
We are looking for Civil Engineers for our upcoming infrastructure projects.
@ProudtobeaCivilEngineer
2 жыл бұрын
Thank you
Boss Nak welder ke
@ProudtobeaCivilEngineer
2 жыл бұрын
We don't have any vacancies at the moment.