Underreaming - Revision history

Designing Buildings at 07:18, 18 November 2020

2020-11-18T07:18:46Z

← Older revision		Revision as of 07:18, 18 November 2020
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	It is possible to drill a pilot hole and then underream, or to drill and underream as part of the the same drilling operation.		It is possible to drill a pilot hole and then underream, or to drill and underream as part of the the same drilling operation.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Foundations.		* Foundations.

Designing Buildings at 07:17, 18 November 2020

2020-11-18T07:17:47Z

← Older revision		Revision as of 07:17, 18 November 2020
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	* Underpinning.		* Underpinning.

−	[[Category:Construction_techniques]] [[Category:Roles_/_services]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Construction_techniques]] [[Category:Roles_/_services]]

Editor at 15:16, 11 September 2017

2017-09-11T15:16:56Z

← Older revision		Revision as of 15:16, 11 September 2017
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	* Piers.		* Piers.
	* Pile foundations.		* Pile foundations.
		+	* Soil nailing.
	* Tension piles.		* Tension piles.
	* Trench fill foundation.		* Trench fill foundation.

Editor at 12:43, 23 March 2017

2017-03-23T12:43:43Z

← Older revision		Revision as of 12:43, 23 March 2017
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	* Foundations.		* Foundations.
		+	* Freezing method.
	* Geothermal pile foundations.		* Geothermal pile foundations.
	* Groundworks.		* Groundworks.

Designing Buildings at 14:03, 17 March 2017

2017-03-17T14:03:56Z

← Older revision		Revision as of 14:03, 17 March 2017
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	Underreaming may also be carried out to create tension piles, where the widened foot resists uplift forces that might otherwise cause the pile to be extracted from the ground. For more information see: Tension pile.		Underreaming may also be carried out to create tension piles, where the widened foot resists uplift forces that might otherwise cause the pile to be extracted from the ground. For more information see: Tension pile.
		+
		+	It can also be used in the formation of ground anchors.

	Typically, the process involves a drill pipe with cutter blades that can be forced open by pumping a fluid into the pipe. The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure. The pumps are disengaged when the desired depth has been reached. The underreamer closes and is pulled out of the hole.		Typically, the process involves a drill pipe with cutter blades that can be forced open by pumping a fluid into the pipe. The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure. The pumps are disengaged when the desired depth has been reached. The underreamer closes and is pulled out of the hole.
		+
		+	It may be necessary to use water flushing systems to remove the reamed spoil from the hole and grout to maintain the integrity of the underream.

	There is the risk that if the underreamer is left in the hole for too long, the amount of material left in the hole increases. Also, if penetration rates are too high, this can result in a corkscrewed, under-gauged hole.		There is the risk that if the underreamer is left in the hole for too long, the amount of material left in the hole increases. Also, if penetration rates are too high, this can result in a corkscrewed, under-gauged hole.

−	~~Where there~~ is a ~~pre-existing~~ pilot hole, ~~a bullnose~~ or ~~the bit below the underreamer is used to assist with guiding it through the borehole. It is also possible~~ to drill ~~the pilot hole~~ and underream ~~to a larger diameter~~ as part of the the same drilling operation.	+	It is possible to drill a pilot hole and then underream, or to drill and underream as part of the the same drilling operation.

	= Find out more =		= Find out more =

Designing Buildings at 13:33, 17 March 2017

2017-03-17T13:33:35Z

← Older revision		Revision as of 13:33, 17 March 2017
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	It is generally undertaken for safety and/or efficiency reasons, or because of restrictions in the ground, that prevent the use of a pier or pile that is wider along its entire length, and is most common on offshore drilling operations, exploration wells, extended reach drilling, and so on.		It is generally undertaken for safety and/or efficiency reasons, or because of restrictions in the ground, that prevent the use of a pier or pile that is wider along its entire length, and is most common on offshore drilling operations, exploration wells, extended reach drilling, and so on.
		+
		+	Underreaming may also be carried out to create tension piles, where the widened foot resists uplift forces that might otherwise cause the pile to be extracted from the ground. For more information see: Tension pile.

	Typically, the process involves a drill pipe with cutter blades that can be forced open by pumping a fluid into the pipe. The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure. The pumps are disengaged when the desired depth has been reached. The underreamer closes and is pulled out of the hole.		Typically, the process involves a drill pipe with cutter blades that can be forced open by pumping a fluid into the pipe. The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure. The pumps are disengaged when the desired depth has been reached. The underreamer closes and is pulled out of the hole.
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	* Grouting in civil engineering.		* Grouting in civil engineering.
	* Piers.		* Piers.
		+	* Pile foundations.
		+	* Tension piles.
	* Trench fill foundation.		* Trench fill foundation.
	* Underpinning.		* Underpinning.

	[[Category:Construction_techniques]] [[Category:Roles_/_services]]		[[Category:Construction_techniques]] [[Category:Roles_/_services]]

Designing Buildings at 13:31, 17 March 2017

2017-03-17T13:31:12Z

← Older revision		Revision as of 13:31, 17 March 2017
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−	Underreaming is ~~the~~ process ~~that is~~ used to widen the foot of a bored hole or foundation ~~piers past the size it was originally drilled to~~ so as to increase ~~the~~ loadbearing area.	+	Underreaming is a process used to widen the foot of a bored hole or foundation pier so as to increase its loadbearing area.

−	~~In principle, underreaming involves the same process as drilling with a bit to create a full gauge hole.~~ It is ~~typically used to provide the correct running~~ and ~~cementing of casing with a wider clearance~~, ~~due either to~~ restrictions in the ground ~~or to run~~ a ~~larger casing size~~.	+	It is generally undertaken for safety and/or efficiency reasons, or because of restrictions in the ground, that prevent the use of a pier or pile that is wider along its entire length, and is most common on offshore drilling operations, exploration wells, extended reach drilling, and so on.

−	~~Underreaming~~ is ~~generally used as for safety~~ and~~/or efficiency reasons,~~ and is ~~most common on offshore drilling operations, exploration wells, extended reach drilling, and so on~~.	+	Typically, the process involves a drill pipe with cutter blades that can be forced open by pumping a fluid into the pipe. The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure. The pumps are disengaged when the desired depth has been reached. The underreamer closes and is pulled out of the hole.

−	~~The process involves~~ the ~~drill pipe being filled with drilling fluid before engaging pumps which force open~~ the ~~cutter blades~~. ~~These~~ are ~~retractable arm tools that are fitted with tungsten carbide insert (TCI) or milled tooth cutters~~, ~~depending on the formation composition~~.	+	There is the risk that if the underreamer is left in the hole for too long, the amount of material left in the hole increases. Also, if penetration rates are too high, this can result in a corkscrewed, under-gauged hole.

−	The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure, while the cutting structure is kept clean and cool by multiple jet nozzles. The pumps are disengaged when the desired depth has been reached. The underreamer closes and pulls out of the hole.	+	Where there is a pre-existing pilot hole, a bullnose or the bit below the underreamer is used to assist with guiding it through the borehole. It is also possible to drill the pilot hole and underream to a larger diameter as part of the the same drilling operation.
−		+
−	There is the risk that if the underreamer is left in the hole for too long, the amount of material left in the hole increases. Also, if penetration rates are too high, then this can result in a corkscrewed, under-gauged hole.	+
−		+
−	~~In the case that~~ there is a pre-existing pilot hole, a bullnose or the bit below the underreamer is used to assist with guiding it through the borehole. ~~Another technique~~ is to drill ~~and ream simultaneously. This allows~~ the ~~drilling of a~~ pilot hole and ~~the underreaming of it~~ to a larger diameter ~~to take place in~~ the same drilling operation.	+

	= Find out more =		= Find out more =

Editor: Created page with "Underreaming is the process that is used to widen the foot of a bored hole or foundation piers past the size it was originally drilled to so as to increase the loadbearing area. ..."

2017-03-15T13:09:38Z

Created page with "Underreaming is the process that is used to widen the foot of a bored hole or foundation piers past the size it was originally drilled to so as to increase the loadbearing area. ..."

New page

Underreaming is the process that is used to widen the foot of a bored hole or foundation piers past the size it was originally drilled to so as to increase the loadbearing area.

In principle, underreaming involves the same process as drilling with a bit to create a full gauge hole. It is typically used to provide the correct running and cementing of casing with a wider clearance, due either to restrictions in the ground or to run a larger casing size.

Underreaming is generally used as for safety and/or efficiency reasons, and is most common on offshore drilling operations, exploration wells, extended reach drilling, and so on.

The process involves the drill pipe being filled with drilling fluid before engaging pumps which force open the cutter blades. These are retractable arm tools that are fitted with tungsten carbide insert (TCI) or milled tooth cutters, depending on the formation composition.

The underreaming tool is kept open by the drilling weight and hydraulics from the pump pressure, while the cutting structure is kept clean and cool by multiple jet nozzles. The pumps are disengaged when the desired depth has been reached. The underreamer closes and pulls out of the hole.

There is the risk that if the underreamer is left in the hole for too long, the amount of material left in the hole increases. Also, if penetration rates are too high, then this can result in a corkscrewed, under-gauged hole.

In the case that there is a pre-existing pilot hole, a bullnose or the bit below the underreamer is used to assist with guiding it through the borehole. Another technique is to drill and ream simultaneously. This allows the drilling of a pilot hole and the underreaming of it to a larger diameter to take place in the same drilling operation.

= Find out more =

=== Related articles on Designing Buildings Wiki ===

* Foundations.
* Geothermal pile foundations.
* Groundworks.
* Grouting in civil engineering.
* Piers.
* Trench fill foundation.
* Underpinning.

[[Category:Construction_techniques]] [[Category:Roles_/_services]]