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Three-Dimensional Model Test of Surrounding Rock Deformation of a New Tunnel Approaching an Existing Tunnel
(1Key Laboratory of New Technology for Construction of Cities in a Mountain Area (Chongqing University), Ministry of Education,Chongqing 400045; 2 School of Civil Engineering, Chongqing University, Chongqing 400045)
Abstract In order to analyze the effects of the approaching distance of an existing tunnel on rock mass deforma? tion during construction of a new adjacent tunnel, a similarity model test and numerical simulation study are conducted based on the approaching section of the Chongqing Liangjiang tunnel. The results show that: 1) the approaching distance between the two tunnel tubes is inversely proportional to the crown settlement and convergence of the left and right tunnel haunches of the new tunnel; 2) the change tendency of the crown settlement complies with that of the convergence of the left and right tunnel haunches during construction of the new tunnel, and it can be summarized as the three phases of rapid increase, slow increase and stabilization; and 3) the tunnel crown settlement is larger than the sum of the haunch convergence, so the designed upper limit of rock mass deformation should be mainly based on the crown settlement for this type of tunnel. A relationship expression regarding the tunnel deformation H(mm)and tunnel approaching distance L(m) is established by means of data fitting, with the correlation coefficients all being more than 0.995, which provides a reference for the design of reserved deformation and the construction of similar projects.
Abstract：
In order to analyze the effects of the approaching distance of an existing tunnel on rock mass deforma? tion during construction of a new adjacent tunnel, a similarity model test and numerical simulation study are conducted based on the approaching section of the Chongqing Liangjiang tunnel. The results show that: 1) the approaching distance between the two tunnel tubes is inversely proportional to the crown settlement and convergence of the left and right tunnel haunches of the new tunnel; 2) the change tendency of the crown settlement complies with that of the convergence of the left and right tunnel haunches during construction of the new tunnel, and it can be summarized as the three phases of rapid increase, slow increase and stabilization; and 3) the tunnel crown settlement is larger than the sum of the haunch convergence, so the designed upper limit of rock mass deformation should be mainly based on the crown settlement for this type of tunnel. A relationship expression regarding the tunnel deformation H(mm)and tunnel approaching distance L(m) is established by means of data fitting, with the correlation coefficients all being more than 0.995, which provides a reference for the design of reserved deformation and the construction of similar projects.
.Three-Dimensional Model Test of Surrounding Rock Deformation of a New Tunnel Approaching an Existing Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(5): 171-179
2017, Vol. 54 