公路跨越既有铁路隧道的方案设计与研究

在既有隧道上方施作建（构）筑物，不仅会引起隧道局部地段的沉降或隆起变形，而且荷载的反复变化也会引起隧道衬砌开裂。因此，在结构设计及施工阶段，应采取合理的措施来避免或减小对下方既有隧道的影响。结合某公路延伸段跨越既有铁路隧道工程，提出了刚性板跨越、桥梁跨越、路基通过3种方案。对上述3种方案进行综合对比分析，发现刚性板方案具有经济性好、实施方便等优点。通过有限元数值模拟，验证了刚性板方案的可实施性。采用刚性板方案跨越既有隧道，在国内尚属首次。本工程的设计可为其他类似工程提供参考。

Case Study on Design of Highway Overcrossing Existing Railway Tunnel

The construction of buildings （structures） above existing tunnels will not only cause settlement or uplift of the tunnel, but also repeated changes in the load will cause cracking of the tunnel lining. Therefore, in the design and construction of the buildings （structures） , rational measures should be taken to avoid or minimize the influence on the existing tunnels below. The extension line of a highway is designed to overeross an existing tunnel, for which three overerossing options, i. e. , overcrossing by means of rigid board, overcrossing by means of bridge and overerossing by means of subgrade, are proposed. Comparison and contrast is made among the mentioned three overcrossing options, which shows that the option of overerossing by means of rigid board has such advantages as being cost efficient and easy In be implemented. The implementation of overcrossing by means of rigid board is verified by means of numerical simulation. It is the first time in China that rigid board is adopted to overeross existing tunnel. The design of the works described can provide referenee for similar works in the future.