Abstract It is difficult to effectively control ground surface settlement during shield construction of metro tunnels
in soft soil area. Based on a 3-D numerical analysis on shield tunnel construction，influence of soft soil distribution on ground settlement induced by shield tunnel construction were discussed. Influence of physical and mechanical behaviors of soil layer on ground settlement was verified by analyzing measurement data. The results show that ground settlement is affected to different degrees when soft soil layer is distributed from ground surface to the scope of 0.23D below tunnel floor (D is outer diameter); influence of soft soil layer on ground settlement is the largest when soft soil layer is distributed in the range of tunnel buried depth and the 0.23D at vault, with the influence rate exceeding 9.9103%; when the distance to tunnel axis is the same, the influence of soft soil layer above tunnel axis on ground settlement is 1.5-6.35 times larger than that below tunnel axis; the maximum ground surface settlement decreases with an increase of weighted averages of soil layer compression modulus and cohesion at shield section, and there is no obvious relationship between the maximum ground surface settlement and weighted average of internal
friction angle; width coefficient i of settlement trough decreases with an increase of weighted average of internal friction angle of soil layer, and there is no obvious relationship among the width coefficient i of settlement trough,weighted averages of soil layer compression modulus and cohesion.
Abstract：
It is difficult to effectively control ground surface settlement during shield construction of metro tunnels
in soft soil area. Based on a 3-D numerical analysis on shield tunnel construction，influence of soft soil distribution on ground settlement induced by shield tunnel construction were discussed. Influence of physical and mechanical behaviors of soil layer on ground settlement was verified by analyzing measurement data. The results show that ground settlement is affected to different degrees when soft soil layer is distributed from ground surface to the scope of 0.23D below tunnel floor (D is outer diameter); influence of soft soil layer on ground settlement is the largest when soft soil layer is distributed in the range of tunnel buried depth and the 0.23D at vault, with the influence rate exceeding 9.9103%; when the distance to tunnel axis is the same, the influence of soft soil layer above tunnel axis on ground settlement is 1.5-6.35 times larger than that below tunnel axis; the maximum ground surface settlement decreases with an increase of weighted averages of soil layer compression modulus and cohesion at shield section, and there is no obvious relationship between the maximum ground surface settlement and weighted average of internal
friction angle; width coefficient i of settlement trough decreases with an increase of weighted average of internal friction angle of soil layer, and there is no obvious relationship among the width coefficient i of settlement trough,weighted averages of soil layer compression modulus and cohesion.
JIA Fuzi1,
2 WANG Lifeng1 YE Junneng3 PANG Jin1 LU Wuquan1
.Influence of Strata Characteristics on Ground Settlement Induced by Shield
Tunnel Construction[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(2): 85-91
2019, Vol. 56 