Abstract In order to examine the long-term bearing capacity of rock tunnel linings, a reliability analysis model for the bearing capacity of a tunnel lining over its lifecycle was established with consideration of time-dependent resistances by taking the initial time and present time as the start times, respectively. On this basis, using a subsea highway rock tunnel located in grade Ⅲ (classification Ⅳ) surrounding rocks under the sea as an example, the long-term bearing capacity reliability of a tunnel lining under different lifetimes was assessed. The results show that: 1) the long-term bearing capacity reliability index of the calculated section of the tunnel lining decreases with an increase of operation time; 2) the long-term bearing capacity reliability index at the haunch of the calculated section is the highest and it is the lowest at the maximum bending moment point, which is to say that the lining at the maximum bending moment point is the least safe; 3) within an operation time of 60 years, the effective probability of the tunnel lining at the maximum bending moment point is more than 99%, and it is between 95% and 99% for the time period after 60 years to the tunnel design life limit (100 years), with the effective probabilities of the tunnel lining at the crown, haunch, and maximum bending moment point being more than 99% during the tunnel′s design lifetime.
Abstract：
In order to examine the long-term bearing capacity of rock tunnel linings, a reliability analysis model for the bearing capacity of a tunnel lining over its lifecycle was established with consideration of time-dependent resistances by taking the initial time and present time as the start times, respectively. On this basis, using a subsea highway rock tunnel located in grade Ⅲ (classification Ⅳ) surrounding rocks under the sea as an example, the long-term bearing capacity reliability of a tunnel lining under different lifetimes was assessed. The results show that: 1) the long-term bearing capacity reliability index of the calculated section of the tunnel lining decreases with an increase of operation time; 2) the long-term bearing capacity reliability index at the haunch of the calculated section is the highest and it is the lowest at the maximum bending moment point, which is to say that the lining at the maximum bending moment point is the least safe; 3) within an operation time of 60 years, the effective probability of the tunnel lining at the maximum bending moment point is more than 99%, and it is between 95% and 99% for the time period after 60 years to the tunnel design life limit (100 years), with the effective probabilities of the tunnel lining at the crown, haunch, and maximum bending moment point being more than 99% during the tunnel′s design lifetime.
.Discussion of Time-Dependent Reliability Analysis for Long-Term Bearing Capacity of Rock Tunnel Linings[J] MODERN TUNNELLING TECHNOLOGY, 2016,V53(3): 68-73
2016, Vol. 53 