CRM Srl – A New Approach to Measure Jet Grouting Columns Diameter Using a Mechanics and Electronics Device (Check Grout)

Presented by: Valerio Salvi

The Jet Grouting practice offers a wide range of application in a variety of soil condition by means of small/medium size rigs and in sharp or limited space not suitable by pile rigs. For this extreme flexibility it found a positive feed back worldwide. The limit of this technique is the diameter definition of the jet grout column, during both the trial test and construction works. The cylindrical bodies of threated soil so obtained, may present variation of diameter also after an extensive field test, and sometimes, a direct measurement (throughout excavation) of the trial columns themselves is not possible. A rich and wide literature offers several solutions to try to solve the above problem, but limits persist because of instruments cost, time consuming process, low accuracy results and complexity of the measuring system. The submitted method consisting of a flexible instrumented pipe able to be pushed out from the drilling string and “travel” through the Jet Grouting column till the contact with the virgin soil. The miniaturized inclinometer chain contained inside the flexible pipe describes, with a high accuracy, the trajectory of the pipe, and defines the parameter required. A deviator assembled at the bottom of the string, allows the lateral exit of the Flexible Pipe.

All Authors:
Marco Angelici, CRM Srl
Valerio Salvi, CRM Srl