|
Abstract The influence of different excavation methods on strata and surrounding rocks of adjacent overlapping tunnels is studied；and the stress-strain laws and deformations of overlapping surrounding rocks and current tunnel linings are revealed，which provides a theoretical basis for the deformation control，support design and excavation optimization design of adjacent overlapping underground projects. Through the FLAC3D numerical simulation，the stress-strain laws and deformations of overlapping surrounding rocks and current tunnel linings and the plastic failure law of overlapping surrounding rocks under the bench method，CRD method and glass method are studied. The research results are as follows：(1) Different excavation methods have different effect degrees on excavation positions during the construction of overlapping tunnels，which reveals the deformation mechanism of current tunnel linings and the dangerous points of lining destruction. (2) According to the development of plastic zone of surrounding rock and tunnel lining deformation，we can obtain that the CRD method is better than glass method and bench method when new line tunnels are excavated；and the deformation control effect of tunnel bottom excavated with CRD method is the best. (3) The bench-CRD-bench method is the ideal scheme when new tunnels cross current tunnels. (4) With any excavation method，the tensile stress will be caused in vaults，skewbacks，straight sides and bottoms of current tunnel linings. Both the maximum and minimum principal stresses in the skewback are the maximum；and the skewback is most easily damaged.
|
|
Received: 28 May 2013
|
|
|
|
2013, Vol. 32 
