Grouting materials in geotechnical practice — which of the following fluids are commonly used for injection grouting to reduce permeability or improve strength?

Introduction / Context:
Grouting is a versatile ground-improvement technique for sealing seepage, filling voids, and enhancing strength/stiffness. The choice of grout depends on soil gradation, permeability, and project objectives. Understanding the range of grout types helps in selecting a workable solution for field conditions.

Given Data / Assumptions:

• Injection into soils or rock joints using pumps and packers as needed.
• Target outcomes may include permeability reduction, void filling, or structural stabilization.
• Compatibility between grout viscosity and soil pore sizes is assumed for effective penetration.

Concept / Approach:

Cement-water mixes (cementitious grouts) suit sands and gravels with larger pores. Clay suspensions (bentonite) are used for sealing and lubrication in drilling and sometimes for grout curtains. Sodium silicate and other chemical grouts penetrate finer sands due to low viscosity and set in place to reduce permeability. Bitumen emulsions are used for waterproofing and flexible sealing in specific geotechnical and pavement contexts.

Step-by-Step Solution:

Verification / Alternative check:

Case histories and standards (e.g., for curtain grouting in dams) document successful use of all listed grout types under suitable conditions.

Why Other Options Are Wrong:

Each individual option describes a legitimate grout; restricting to one would be incomplete.

Common Pitfalls:

Attempting to inject high-viscosity cement grout into silty sands without pre-treatment; ignoring grout-soil chemical compatibility and set time.

Final Answer:

all the above