Prefabricated Horizontal Drain is a Prefabricated pocket style horizontal drain (PHD) that improves soft ground areas. It is made of a mechanically strong PP core and a nonwoven filter jacket that is a specialized drainage filter material Prefabricated Horizontal Drain expedites soil consolidation by facilitating rapid drainage of pore water discharged through vertical drains installed in soft ground.

 

 

Prefabricated Horizontal Drain is installed by connecting with a part of prefabricated vertical drain (Prefabricated Vertical Drain) exposed outside of the ground after installation. Prefabricated Horizontal Drain can effectively and economically replace the horizontal layer of natural aggregates (sand and gravel) thanks to its high level of horizontal drainage. 
 

[Mechanism of soft ground improvement using Prefabricated Vertical Drain and Prefabricated Horizontal Drain

 

Core structure of 山 shape can prevent filter insert to water channels under high pressure in comparison to other types of core structures more effectively.

 

Comparison of Filter intrusion into channel by core shape

 

Advantages of Prefabricated Horizontal Drain

Comparison of horizontal drainage methods

	Prefabricated Horizontal Drains	Fiber-Mat	Natural Aggregate Mat
Section
Description	Pore water discharged to ground surface through installed PVD is horizontally drained through PHD.	Pore water discharged to ground surface through installed PVD is horizontally drained through natural fiber mat.	Pore water discharged to ground surface through installed PVD is horizontally drained through natural sand and/or gravel layer.
Characteristics	- Thanks to the strong structure of the water channel with its interior support, stable discharge ≥3,500cm3/s at surcharge loading of 500kPa is facilitated.- Easy to install and low cost	- Eco-friendly material using natural coir and jute - Unstable quality as products are imported and manually produced - Significant reduction of water channel under surcharge	- Plenty of experience applied and widely used for soil improvement - Environmental damage in securing quality materials (causing public complaint) - Relatively high changeability of supply capacity and price according to how available the supply is at any moment
Cost	USD 6.4/m2	USD7.7/m2	USD11.6/m2
Economic efficiency	High	Middle	Low
Validity for selection	◎

 

 ※ Cost information given above is based on general conditions in Korea as of March, 2014 for your reference only. 
    It is changeable according to site and other conditions.