What is the main purpose of grouting?

Grouting is used to reduce soil/rock permeability, increase its strength and stiffness, or to fill voids. (Clause 1.2)

How do I choose between permeation and compaction grouting?

Permeation grouting fills voids in granular soils without displacement, while compaction grouting densifies loose soils by injecting a stiff grout mass. The choice depends on soil type and project objective. (Table 4)

What is the 'split-spacing' method in grouting?

It's a staged grouting sequence where primary holes are grouted at a wide spacing, followed by secondary holes in between them, and then tertiary holes if needed, to ensure complete and uniform ground treatment. (Clause 7.4)

What is 'refusal' in grouting?

Refusal is the condition where the ground formation stops accepting grout at the specified maximum pressure, indicating that the voids in that zone are effectively filled. (Clause 7.5.3)

IS 15284 Part 1

: 2003

Code of Practice for Ground Improvement - General Guidelines for Selection of Ground Improvement Techniques

CurrentSpecializedCode of PracticeBIMGeotechnical · Geosynthetics and Ground Improvement

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This standard provides a framework and general guidelines for selecting appropriate ground improvement techniques to address various problematic soil conditions. It classifies different methods and offers a decision-making flowchart (Annex A) based on soil type, desired engineering improvement, and applicability of techniques.

Provides general guidelines for the selection of appropriate ground improvement techniques.

Quick Reference Values

Typical Grout Viscosity (Marsh Cone)35-50 seconds

General Grouting Pressure Limit20-25 kPa per meter of depth (to avoid hydrofracture)

Typical Target Permeability post-grouting< 10^-5 cm/s

Bleeding Limit for Cement Grout< 5% of volume

Max Water Temperature for GroutingNot more than 27 °C

Practical Notes

Verification of ground conditions via boreholes is critical before finalizing the grouting method and parameters.

Continuous monitoring of grout pressure and volume (grout take) is essential to control the process and avoid ground heave or damage to nearby structures.

Post-grouting tests, such as permeability tests (e.g., Lugeon test) or in-situ strength tests, are necessary to validate the effectiveness of the ground improvement.