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MEASUREMENTS OF GROUND DEFORMATIONS BEHIND BRACED EXCAVATIONS (2009)
The deformation behavior of earth retaining wall and backside ground due to braced excavation were measured at the construction sites of Osaka Subway Line No. 8. It was observed that backside ground moved to excavation & down side along a circular slip following the wall deflection, and its influence spread to the ground surface. The backside ground surface settlement near the wall was suppressed due to the friction between wall and surrounding ground, and maximum settlement occurred at some distance from wall in the 45–60 degree area from the bottom of the wall. The backside ground deformation area decreased exponentially with the distance from the wall. As a result each observed data from monitoring sites was analyzed statistically according to the soil characteristic, wall deflection and surface settlement in prominent soft clay layer were larger than those in prominent sand and gravel layer. The relation between the wall deflection area Aδ and backside ground settlement area As was that As∼= (0.2–0.3)×Aδ in prominent soft and sensitive clayey layer. The backside ground settlement of this observed data converged smaller than past data.
Geotechnical Aspects of Underground Construction in Soft Ground – Ng, Huang & Liu (eds), © 2009 Taylor & Francis Group, London
Geo-Research Institute, Osaka, Japan