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CONSIDERATION OF DESIGN METHOD FOR BRACED EXCAVATION BASED ON MONITORING RESULTS (2009)
A comparison between observed data and design value of earth retaining wall deflection due to braced excavation was carried out in soft and sensitive clay ground of some construction sites of Osaka Subway Line No.8. The beam-spring model was employed in the braced design method, and it was taken into account the characteristics of the Osaka soft ground, and there was good agreement between the observed data and design value in past results. According to this comparison, the observed wall deflection was larger than the designed one in some construction sites consisted of the soft and sensitive clay layer with 10 to 20m thickness. In this paper, the measuring process of the horizontal coefficient of subgrade reaction kh in the excavation side of soft clay layer is discussed. As the value of kh became small depended on the wall deflection, the new knowledge has been employed on the design method. It is found that the calculation with the revised design method agree well with the monitoring data.
Geotechnical Aspects of Underground Construction in Soft Ground – Ng, Huang & Liu (eds), © 2009 Taylor & Francis Group, London
Osaka Municipal Transportation Bureau, Osaka, Japan