Grouting to Protect Structures and Utilities During Nearby Construction Activities-PPT Presentation

PPT Presentation

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The presentation examines grouting methods used to protect buildings and utilities during nearby construction, drawing on four case histories.<br /><br />For a hospital expansion, planned pit or pier underpinning proved difficult to construct. Permeation grouting was tested but achieved limited penetration, so a composite system of grouted micropiles and a soil-nail wall was used instead.<br /><br />For renovation near a subway fan-shaft structure and a neighboring warehouse, jet grouting was intended to control water inflow and protect the shaft. Large grout takes, caused by loose soils, underground voids, and grout migration, led to heaving, cracks, and clogged drains. Work was stopped, and micropiles founded in rock were selected for the subway structure; the warehouse required drainage and slab repairs.<br /><br />In another project, permeation grouting was used behind underpinning pits beside historic brick buildings. Areas without grouting settled by up to 50 mm and developed major cracks, while grouted areas settled 0–13 mm, demonstrating the benefit of ground treatment in suitable conditions.<br /><br />The presentation also describes jet and compensation grouting used to protect structures and utilities during tunnel construction. Compensation grouting helped address ground loss beneath a building slab.<br /><br />The authors conclude that grouting methods must be matched to soil conditions, site experience, and the structures being protected. Permeation grouting can be a relatively low-impact option in suitable granular soils, while jet grouting can treat a wider range of soils but requires careful control to prevent heave and damage. Compaction grouting suits loose, compactible granular soils; compensation grouting can limit the effects of construction-related movement when applied promptly. Instrumentation and clear response plans are essential for managing risks.

Keywords

grouting

permeation grouting

jet grouting

compensation grouting

micropiles

underpinning

construction protection

soil stabilization

tunnel construction

ground movement