A Study of Ground Deformation and Adjacent Building’s Safety due to Construction of Diaphragm Wall

• Main Authors: Tzu-Yu Huang, 黃子毓
• Other Authors: Horn-Da Lin
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/49529402533529659479

碩士 === 國立臺灣科技大學 === 營建工程系 === 91 === According to the results of field observation data from Taipei Rapid Transit System, significant ground deformation has been recorded during the construction of the diaphragm wall, especially in soft clay. The maximum surface settlement induced by diaphragm wall construction can be as much as thirty percent of the final excavation settlement. Thus, ignoring this settlement will increase the damage potential of the adjacent building. This study aims to better understand ground movements and adjacent building’s responses due to diaphragm wall construction, using a full-scale field test. From the results of the observed field data, horizontal displacement due to diaphragm wall construction can reach 16mm at the depth of 30m below ground surface at the location of 5.5m away from the wall. The influence zone of surface settlement is about twice the diaphragm wall depth. In addition, pore water pressure will also rise during the construction of the diaphragm wall. Building’s settlement of spread footing is the same as the surface settlement of ground. However, the settlement of raft foundation is smaller than the surface settlement about 85-90 percent of the surface settlement. Diaphragm wall construction may also induce adjacent building’s incline. The tilt perpendicular to the wall direction is much greater than the tilt parallel to the wall direction. Tilt of building on the spreading footing is much larger than that of building on the raft foundation. This means building on the spread footing is vulnerable to diaphragm wall construction. The observed field data show that the inclination ratio and the tilt are approximately equal. Therefore, the degree of building inclination can be represented as the inclination ratio instead of the tilt. Finally, the envelope of the observed building’s inclination ratio show that the influence zone of building inclination is about 2.5 times the depth of diaphragm wall. For present practices, the zone of field observation is only 1.5 times the depth of diaphragm wall. In light of this study, larger monitored zone should be considered.