Study on Deformation Characteristics and Control Measures of Shallow Large-span Loess tunnels
(1 CCCC Second Harbor Engineering Co., Ltd, Wuhan 430040; 2 Shaanxi Provincial Major Laboratory for Highway Bridge & Tunnel,
Chang'an University, Xi′an 710064; 3 CCCC Highway Bridges National Engineering Research Centre CO., Ltd., Beijing 100088; 4
Research and Development Center of Intelligent Manufacturing Technology for Transportation Infrastructure in the Transportation
Industry, Wuhan 430040; 5 Key Laboratory of Long Bridge Construction Technology for Transportation Industry, Wuhan 430040)
Abstract：
In order to study the deformation characteristics and the corresponding control technology of large-span
loess tunnels, guide the loess tunnel design & construction and ensure the construction safety, based on a tunnel project being under construction, this paper analyzes the surrounding rock deformations and the causes according to field monitoring data of the large deformation section, as well as proposes corresponding control measures and parameters. The study results show that great differences exist in surrounding rock deformations of a shallow loess tunnel affected by the properties of overlying surrounding rocks, the surrounding rock deformation rate is generally large at the early stage of excavation with the maximum settlement rate of 54.6 mm/d; the deformation lasts for a long time and tends to converge gradually after about 45 d; the accumulative deformation is large and significantly affected by excavation disturbance, in particular, the surrounding rock deformation during the lower bench excavation accounts for about 70% of the total deformations; the large deformation process of surrounding rocks will experi?
ence four stages of "fast development, sustainable development, slow development and gradual stabilization", in the stage of sustainable development it is susceptible to external environment with a large fluctuation in surrounding rock deformation rate, at the stage of slow development the invert should be closed as soon as possible to effectively restrain the deformation development of surrounding rocks; the regression curve model can be directly used to predict the deformation of soft loess tunnels.
CHEN Peishuai1,
2 WANG Wei1,
3 WU Zhongshi1 etc
.Study on Deformation Characteristics and Control Measures of Shallow Large-span Loess tunnels[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(1): 203-211
2021, Vol. 58 