Why Using Self-drilling Hollow Bolt As Anti-floating Rock Anchor Pile?

Time:2022-04-25From:sinorock View:

As an advanced method of foundation supporting, self-drilling hollow bolt is widely used as civil construction foundation, tower foundation, soundproof wall foundation, new building pile foundation, and anti-floating rock anchor pile. It’s easy to understand that using self-drilling hollow bolt as the foundation of different constructions. However, why using it as anti-floating rock anchor pile? And how?

What Is Self-drilling Hollow Bolt?

It is a rock anchoring system that contains a one-time use drill bit, a rock bolt with an inner hole, a coupler to double, or triple the hollow bolt or even, a combination of a plate and a nut to transform the load to hollow bolt, and a centralizer to ensure the hollow bolt staying at the central of the drilling hole.

The designation of inner hole of the rock bar makes it possible to drill and grout simultaneously. Therefore, it is suitable for unstable geological conditions where are difficult to drill holes or the drilling hole collapse easily, such as broken rock, loose soil, and others.

self drilling hollow bolt

Construction Process of Using Self-drilling Hollow Bolt As Anti-floating Rock Anchor Pile

Preparation before construction: Check whether the functions of the drilling rig are normal, whether the drill bit and the rod body are damaged, and whether the inner path of rod body is unblocked, etc. After all these preparation is OK, screw to connect the hollow bolt body to be used with the drill bit;

Drill and grouting: Connect the rod body and the grouting tube to the drilling rig through a rotary grouting adapter, and grouting during the drilling process to achieve simultaneous completion of drilling and grouting;

Extend the length of hollow bolt: If the length of a single self-drilling anchor bolt cannot reach the designed drilling depth, the couplers can be used to double or triple the hollow bolt to meet the design requirements;

Install the backing plate and nut: After the grouting is completed, install the backing plate and the nut in sequence on the exposed part of the self-drilling anchor bolt outside the rock body close to the construction surface to ensure the anchoring effect.

Anti-Floating Rock Anchor Pile Specification (one of all)

Hollow Bar

Size	Outer Dia. (mm)	Ultimate Load (kN)	Yield Load (kN)	Weight (Kg/m)
SER25N	25	200	150	2.35

Coupler

Size	Outer Dia. (mm)	Length (mm)	Weight (Kg/pc)	Note
SSR25	36	150	0.66	With sealing structure
SER25	36	150	0.68	Without sealing structure

Hex Nut

Size	Key Size (mm)	Length (mm)	Weight (Kg/pc)	Note
SSR25	41	30	0.20	Heat treatment
SER25	41	35	0.23	Without heat treatment

Domed Nut

Size	Key Size (mm)	Length (mm)	Weight (Kg/pc)	Note
SER25	41	40.5	0.31	Without heat treatment

Domed Plate

Size	Dimensions (mm)	Thickness (mm)	Hole Dia. (mm)	Weight (Kg/pc)
SER25	150×150	8	30	1.40
	150×150	5	28	0.85
	200×200	10	32	3.20

Drill Bit

Size	Outer Dia. (mm)	Application Range (Advice)
EX			Sand, fills, gravel
SSR25/42	42
SSR25/51	51
EXX			Softer sedimentary rocks such as marls, mudstones, siltstone
SSR25/42	42
SSR25/51	51
ES-F			Gravel, soft rock
SSR25/42	42
SSR25/51	57.5
ESS-F			Weathered rock, stone walls, rubble
SSR25/42	42
SSR25/51	51
EY			Competent ground, strong rock
SSR25/51	51

Why Using Self-drilling Hollow Bolt As Anti-floating Rock Anchor Pile?

It performs well in anti-corrosion when being made of stainless steel, hot dip galvanized, or epoxy coated, and is suitable for coastal and other corrosive environments, such as the projects effected badly by rain or groundwater. While, the rebar will be very easily corroded in thus conditions.

The grouting of self-drilling hollow bolt can be completed when drilling, which saves part of the whole construction term. The construction efficiency will be greatly improved.

Since the self-drilling hollow bolt can be made of stainless steel, it has excellent weldability, high strength, and wear resistance.

So, in many anti-floating foundation projects, we use self-drilling hollow bolt as anti-floating rock anchor pile. Sinorock provides various of self-drilling hollow bolts. If you’re interested, feel free to contact us.

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