Patent ID: 8217668

Claim:
A method of evaluating a ground reinforcement effect using 4-D electrical resistivity monitoring, wherein the ground reinforcement is made up on an underground cavity through cement mortar grouting, the method comprising: (a) installing a survey line for measuring electrical resistivity in a ground reinforcement zone; (b) measuring the electrical resistivity of the ground reinforcement zone through the survey line before grouting mortar, and imaging three-dimensional electrical resistivity distribution in the ground reinforcement zone for a first time by applying a three-dimensional electrical resistivity inversion to the measured results; (c) analyzing electrical resistivity data and images resulting from step (b) to determine that the ground reinforcement zone includes an underground cavity; (d) selecting a grouting zone based on the electrical resistivity data, the images, and the location of the identified underground cavity; (e) causing cement mortar to flow into grouting zone, including the identified underground cavity, thereby grouting the mortar; (f) measuring the electrical resistivity of the ground reinforcement zone through the survey line while or after grouting the mortar, and imaging the three-dimensional electrical resistivity distribution in the ground reinforcement zone for a second time by applying the three-dimensional electrical resistivity inversion to the measured results; and (g) calculating a change ratio of the electrical resistivity measured while or after the grouting in (f) to the electrical resistivity measured before the grouting in (b), and evaluating the ground reinforcement effect by imaging the three-dimensional electrical resistivity distribution in the ground reinforcement zone on the basis of the change ratio.