Method for Prevention of Liquefaction Caused by Earthquakes Using Grouting Applicable to Existing Structures

Abstract

Ground liquefaction is causing great damage to the structure of land during earthquakes. Accordingly, various liquefaction damage reduction methods have been studied and developed. However, most of the ground liquefaction prevention methods have limitations in their application to existing structures. Therefore, in this study, a ground liquefaction damage reduction method, applicable to existing structures, was studied using the grouting method. A 1-G shaking table test was performed, and the ground was created with Jumunjin standard sand. A two-story model structure was manufactured by applying the similarity law, and an input wave applied a sinusoidal motion with an acceleration level of 0.6 g and a frequency of 10 Hz. The grouting chemical was produced by mixing water and cement, and the effect of reducing structural damage was analyzed according to various mixing ratios; in addition, the separation distance between the grouting chemical injection point and the structure was analyzed. As a result of the analysis, when the ground was reinforced by applying the grouting method, the settlement of the structure was about 84% smaller than when the ground was not reinforced, and the mixing ratio with the smallest settlement was 0.45. In addition, when there was no separation distance between the structure and the grouting chemical injection point, it was confirmed that the effect of reducing structural damage was the greatest. These research results will be used as basic data for developing a grouting method applicable to existing structures in the future.

Keywords

• liquefaction
• grouting method
• 1-G shaking table
• liquefaction damage reduction method
• scaled model experiment