Introduction
Rapid urbanization and the increasing demand for infrastructure development have led to construction activities in densely populated and environmentally sensitive areas. In such conditions, conventional ground improvement methods often pose challenges related to vibration, noise, space constraints, and risk to adjacent structures. Jet grouting has emerged as a highly effective and versatile ground improvement technique, particularly suited for urban and sensitive construction environments. This article discusses the field applications of jet grouting, highlighting its advantages, methods, and real-world uses in challenging construction scenarios.
Overview of Jet Grouting
Jet grouting is a soil stabilization technique that involves injecting high-pressure cementitious grout into the ground through small-diameter boreholes. The high-energy grout jet erodes and mixes with the in-situ soil, forming soil–cement columns or panels with improved strength and reduced permeability. Depending on project requirements, jet grouting can be carried out using single, double, or triple fluid systems.
Suitability for Urban and Sensitive Areas
Urban and sensitive construction zones—such as city centers, heritage sites, hospitals, railway corridors, and environmentally protected regions—require minimal disturbance to surroundings. Jet grouting is particularly suitable in these contexts due to:
- Low vibration and minimal noise during execution
- Flexibility to operate in restricted spaces
- Ability to treat variable soil conditions
- Precise control over treatment geometry
Field Applications
1. Foundation Underpinning and Retrofitting
In urban areas with aging infrastructure, jet grouting is widely used for underpinning existing foundations. It strengthens weak soils beneath buildings without the need for large excavation, ensuring structural stability while minimizing disruption to occupants and nearby structures.
2. Excavation Support and Groundwater Control
Jet grouting is commonly applied to form impermeable cutoff walls or soil–cement panels around deep excavations. This is especially useful in congested city environments where groundwater control and excavation stability are critical, such as metro stations, basements, and underground parking structures.
3. Tunnel and Underground Construction
For tunnel construction in urban settings, jet grouting is used to improve ground conditions ahead of tunnel boring machines (TBMs) or during the construction of cross passages and shafts. It enhances soil strength and reduces settlement risks, protecting nearby buildings and utilities.
4. Protection of Heritage and Sensitive Structures
Historic monuments and heritage buildings are highly sensitive to ground movement. Jet grouting provides a non-intrusive solution to improve foundation soils and control seepage without causing vibrations or damage, making it ideal for conservation projects.
5. Infrastructure Near Railways and Roads
Jet grouting is effectively used near active railways, highways, and bridges where continuous operation must be maintained. Its low-impact nature allows ground improvement works to proceed without interrupting traffic or compromising safety.
6. Environmental and Waterfront Projects
In environmentally sensitive areas such as riverbanks, coastal zones, and contaminated sites, jet grouting helps in soil stabilization, seepage control, and containment of pollutants. The method supports sustainable construction practices by limiting excavation and soil disposal.
Advantages in Field Implementation
- Adaptability to complex and variable soil profiles
- Minimal impact on adjacent structures
- High strength and durability of treated ground
- Capability to form customized shapes and patterns
- Effective groundwater control
Challenges and Considerations
Despite its advantages, jet grouting requires careful design and quality control. Field challenges include spoil management, grout consumption control, and verification of column integrity. Skilled operators, proper monitoring, and post-treatment testing are essential to ensure successful outcomes.
Conclusion
Jet grouting has proven to be a reliable and efficient ground improvement technique for urban and sensitive construction areas. Its ability to enhance soil strength, control groundwater, and minimize environmental and structural impacts makes it an indispensable tool in modern geotechnical engineering. As cities continue to expand vertically and underground, the role of jet grouting in safe and sustainable construction is expected to grow significantly.
