Greenfield Test and Numerical Study on Grouting in Silty Clay to Control Horizontal Displacement of Underground Facilities

Compensation grouting has been widely applied for the vertical deformation control of constructed facilities. However, few studies have been conducted on the horizontal displacement control of underground facilities using grouting. A field test of compensation grouting was conducted in a greenfield site to investigate the mechanism of horizontal displacement control. Both horizontal displacement and pore-water pressure of soil were monitored. A sophisticated finite-element model was developed and verified by field measurements. A comparison of various models showed that it was necessary to consider the nonuniform expansion of the conditioned zone for displacement prediction and the fissures for the simulation of pore pressure dissipation. The parametric study showed that the grouting-induced horizontal displacement of the silty clay could be predicted by a power model. The displacement decreased to 10% of the maximum value at a distance of 3 m, which could be defined as the effective controlling range of grouting. A hyperbolic model was proposed to calculate the efficiency of horizontal displacement. The efficiency of horizontal displacement reached 90% of its limit value when the grouting volume was approximately 2.3 m(3), which could be regarded as an optimum grouting volume in practice.