Abstract Large deformations occurred during the construction of Maoyushan tunnel exit on Lanzhou-Chongqing Railway. A three-dimensional numerical model with FLAC3D was established to simulate tunnel construction with various bench lengths, closure time of invert, anchor lengths and casting time of secondary lining. Results indicated that the bench length was the key to control deformation, and the upper bench length should be shortened as much as possible; invert played a significant role to control deformation in squeezing rocks and it should be closed as early as possible; tunnel deformations gradually decreased with the increase of anchor lengths up to 8m; and secondary lining should be cast promptly after excavation to effectively control the creep deformation of surrounding rocks.
Abstract：
Large deformations occurred during the construction of Maoyushan tunnel exit on Lanzhou-Chongqing Railway. A three-dimensional numerical model with FLAC3D was established to simulate tunnel construction with various bench lengths, closure time of invert, anchor lengths and casting time of secondary lining. Results indicated that the bench length was the key to control deformation, and the upper bench length should be shortened as much as possible; invert played a significant role to control deformation in squeezing rocks and it should be closed as early as possible; tunnel deformations gradually decreased with the increase of anchor lengths up to 8m; and secondary lining should be cast promptly after excavation to effectively control the creep deformation of surrounding rocks.
HE Lei,
YANG Bin,
WANG Geng-Feng etc
.Research on Construction Dynamic Control and Optimization of a Tunnel in Soft Rock under High In-situ Stresses[J] MODERN TUNNELLING TECHNOLOGY, 2011,V48(2): 44-48
2011, Vol. 48 