IS 15284 (Part 2) provides an engineering reference for ground-improvement works involving preconsolidation using vertical drains. This technique is commonly considered where soft, compressible or saturated soils require accelerated consolidation before construction of embankments, foundations or other civil infrastructure.

What is IS 15284 (Part 2) : 2026?

IS 15284 (Part 2) : 2026 is the Indian Standard Code of Practice covering design and construction of ground improvement through preconsolidation using vertical drains.

Vertical drains are used as part of ground-improvement systems to shorten the drainage path within soft or saturated soils. This allows excess pore water to dissipate more efficiently during preloading or surcharge, helping the ground consolidate before the permanent structure or infrastructure is constructed.

What is Preconsolidation Using Vertical Drains?

Preconsolidation is a ground-improvement technique in which compressible soil is subjected to loading before the final structure is completed. The objective is to induce a significant portion of the expected settlement in advance.

Vertical drains can be installed within the soil to provide shorter drainage paths and accelerate consolidation. Depending on the project and soil conditions, the system may be used together with surcharge loading or other preloading methods.

Purpose of Vertical Drain Ground Improvement

Soft and compressible ground may experience significant long-term settlement when subjected to structural or embankment loads. Where natural consolidation would take a long period, engineered vertical drainage can be considered to accelerate the consolidation process.

The technique is relevant to infrastructure projects constructed over weak ground, including embankments, transport infrastructure, industrial developments and other civil engineering works where settlement control and ground preparation are important design considerations.

Revision of IS 15284 (Part 2)

IS 15284 (Part 2) : 2026 is the First Revision of IS 15284 (Part 2) : 2004. The previous edition was titled Design and Construction for Ground Improvement — Guidelines Part 2 Preconsolidation Using Vertical Drains.

BIS established the revised standard on 21 July 2026. The previous 2004 edition will continue to remain in force concurrently until 21 January 2027, after which it is scheduled to be withdrawn.

Who Uses IS 15284 (Part 2)

This standard is a working reference for:

• Geotechnical engineers: To evaluate and design ground-improvement systems involving preconsolidation and vertical drains.

• Civil engineering consultants: To specify suitable ground-treatment methods for infrastructure projects constructed over compressible soils.

• Ground-improvement contractors: To execute vertical drain installation and associated ground-treatment activities in accordance with project specifications.

• Infrastructure developers: To apply standardized engineering references when planning development over soft or compressible ground.

• Project and quality teams: To review ground-improvement design, installation and project documentation against applicable engineering requirements.

Transition to IS 15284 (Part 2) : 2026

Organizations currently referring to IS 15284 (Part 2) : 2004 should review the revised 2026 Code of Practice and update relevant engineering specifications, design documentation, tender requirements and construction procedures during the transition period.

The earlier IS 15284 (Part 2) : 2004 remains concurrently valid until 21 January 2027.

Frequently asked questions (FAQ)

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