• Summary
• Specification
• Examples

Shape and types

Properties

1. - Prevents degradation of water drain efficiency caused by penetration of non-woven fabric

   

2. - In case of penetration of non-woven fabric, reduction of water passage section occurs

   

3. - Prevents cutting or bending by upper ground subsidence

   

Regardless of what type of filter is used, it maintains high efficiency for water passage.

· Harmonica-shaped PBD – Filter materials may penetrate the core, leading to degradation of water drain efficiency.

Harmonica-shaped PBD

Division	Imported filter material + Harmonica-shaped PBD	Domestic filter material + Harmonica-shaped PBD	Comparison
Shape			Reduction Ratio	Erosion Control
Test Result(㎤/sec)	63	4(Failure)	94%	More than 25

· Harmonica-shaped PBD – Filter materials may penetrate the core, leading to degradation of water.

1. ① High efficiency for water drain by preventing penetration of filter materials
2. ② Regardless of what type of filter is used, it maintains high efficiency for water passage.
3. ③ Maintains high efficiency despite degradation of filter from long-term use.

Harmonica-shaped PBD

Division	Imported filter material + C-PBD	Domestic filter material + C-PBD	Comparison
Shape			Reduction Ratio	Erosion Control
Test Result(㎤/sec)	138	86(합격)	38 %	More than 25

- Drain Efficiency Comparison

1. ① Short-term Water Drain Performance (One week test)
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- Reduces the consolidation time and the construction cost

1. ① The amount of reduction of consolidation time

   The amount of reduction of consolidation time

   Division	According to depths of vertical drain, 95% consolidation time (a day)
   	10M	30M	60M
   Harmonica-shaped PBD	311	318	340
   Cylindrical PBD	241	244	252
   Time Reduction	70(77%)	70(77%)	88(74%)

   (Identical Soil Conditions, Period of improvement 12 months, Placing Interval 1.4m X 1.4m Hansbo-1981)
2. ② Supply and cost reduction

   Period of improvement	Type	Placing Interval	Placing Number	Placing Hook	Cost(Hundred Million won)	Amount of reduction
   6months	Harmonica-shaped PBD	1.0mX 1.0m	250,000	7,625,000	122	Supply	132 million m
   	C-PBD	1.1mX 1.1m	206,612	6,301,653	100	Cost	22 Hundred Million
   6months	Harmonica-shaped PBD	1.4mX 1.4m	127,551	3,890,306	62	Supply	50 million m
   	C-PBD	1.5mX 1.5m	111,111	6,301,653	54	Cost	22 Hundred Million

   (Construction Cost by PBD Method – 1.600 won/m, Improvement Area – 25㎡, Depth of Vertical Drain – 40m)