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To reduce the impact of installation of horizontal jet grouting columns on surrounding ground, a new horizontal jet grouting technique termed controlled discharge horizontal jet grouting is developed. A field trial programme is conducted to verify the application of the technique technology. Field measurements of ground surface displacement and induced excess pore-water pressures are obtained during implementation of the technique. Five trial jet grout columns are installed at 2 m below the ground surface and subsequently exposed for measuring and testing. The observed vertical displacements of the ground surface range from 0 . 4 to 9 . 4 mm, with maximum excess pore-water pressures generated during the field trial varying between 3 . 5 and 25 . 6 kPa. The diameters of the exposed jet grout columns range from 1 . 1 to 1 . 4 m. Core samples extracted from the trial jet grout columns indicate that the quality of the jet-grouted soil formed is good, with total core recovery of 70-95% and rock quality designation of 79-92%.Unconfined compressive strength tests show that the 28-d strength ranges from 0 . 9 to 1 . 5 MPa, and Young's modulus at 50% failure load (E 50 ) is between 61 . 5 and 145 . 3 MPa. The field trial results confirm the applicability of the technique for achieving low-impact installation of horizontal jet grouting.

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