In the behavior of earth retaining walls, the load-displacement relation appears different according to variables such as the interaction between the structure and the ground, the initial stress of backfill and stress relaxation, and there are also dynamically unexplained factors that may affect the behavior of earth retaining walls through the stages of construction. These factors make it difficult to predict the behavior of earth retaining walls.
The present study selected construction sites that use different types of earth retaining walls and strutting methods among urban excavation sites with similar ground structure. We made comparative analysis of the horizontal displacement of earth retaining walls, the settlement of surrounding ground and the results of numerical analysis using data collected at each stage of excavation using inclinometers, and examined the applicability of the results. In addition, we analyzed the horizontal displacement of walls and the settlement of backfill at each stage of excavation according to the type of earth retaining walls and wall strutting method, and obtained correlations among them by comparing the results of field measurements with management standards in previous researches. The conclusions of this study are as follows.
1. The ratio of the maximum horizontal displacement was 0.23%H in case of soft walls and 0.18%H in case of rigid walls. In case of soft walls, the ratio was higher than 0.2%H suggested by NAVFAC DM-7.2, Clough & O'Rourke, Chang Yu-Ou, Lee Jong-gyu, etc. and lower than the maximum level of 0.5%H, showing a relatively stable result. In case of rigid walls which is relatively stable compared to management standards at home and abroad.
2. The ratio of the maximum horizontal displacement was 0.36%H in case of soft walls supported by struts and 0.22%H in case of rigid walls, which were higher than 0.2%H measured at sites with ground composed of earth and sand (Clough & O'Rourke, 1990; Lee Jong-gyu, 1993). On the other hand, the ratio was 0.20%H in case of soft walls supported by earth anchors and 0.19%H in case of rigid walls, which were similar to management standards suggested. In addition, earth anchor support showed a lower value than strut support, showing that earth anchor support is more effective in wall confining than strut support.
3. As to horizontal displacement and the settlement of ground surface according to the type of earth retaining wall, numerical analysis was overestimated by around 68~70% compared to that of field measurement, and numerical analysis was overestimated by around 42~48% compared to that of field measurement. This is probably because ground conditions and ground parameters assumed in design did not exactly agree with the actual conditions and parameters and as a result the behavior of surrounding ground was not predicted accurately.