基于FDEM的隧道衬砌裂缝开裂过程数值分析

Numerical modeling of cracking of tunnel lining by combined finite-discrete element method

采用杂交有限元–离散元法(FDEM),与日本等比尺浅埋隧道衬砌试验结果进行了对比分析。数值模型较好地再现了试验中衬砌结构性裂缝的初裂、增扩直至破坏的全过程。其次,建立荷载结构模型,针对影响衬砌开裂的3个主要荷载因素,即局部偏压、背后空洞和拱顶松弛地压,分别研究了这些压力不同作用位置、作用范围、作用大小下的裂缝扩展过程、分布规律。为用非连续方法研究衬砌裂缝开裂过程提供了借鉴,同时也为隧道衬砌裂缝病害的防治与加固修复打下了基础。

By using the combined finite-discrete element method（FDEM） and comparing with the laboratory test results of prototype concrete lining segment in Japan, it is obviously found that the initial cracks, crack propagation and collapse of the concrete segment of tunnel are in good agreement with the results of numerical model. Then, by establishing the model for load structure, three dominant pressures including local bias pressure, local void behind lining（pressure free）, and loose pressure on crown are respectively taken into account to investigate the process of cracking and the distribution of cracks under their different positions, ranges and magnitudes imposed on the concrete lining. This study may provide valuable insight for understanding the process of cracking in concrete lining of tunnel by means of continuous-discontinuous methods to evaluate the stability and sustainability of tunneling structures. It also lays the foundation for the crack prevention and reinforcement of tunnel lining.