Extending chemo-thermal quality assessment for jet grouting

Today quality assessment of jet grouting focuses on the determination of the diameter of the column and the cement content of the improved soil exploiting the exothermal nature of the hydration of cement. This is accomplished by in situ temperature measurement followed by a back-calculation employing a simplified one-dimensional chemo-thermal finite-element simulation model. The underlying assumptions, such as simple geometric properties and disregarding the construction process, lead to the questions of the range of applicability of the existing quality-assessment tool and, in what cases a more refined simulation approach becomes necessary. By means of a two-dimensional simulation, the influence of the geometric properties (height/radius ratio) of jet-grouted columns and of adjacent columns on temperature development is investigated. Finally, the simulation results are compared with the measurements from a construction site, showing the benefit of the proposed model and the simulation approach in the case of complex jet-grouting applications.