在岩溶地区，列车振动荷载已成为引起铁路周边地表岩溶塌陷的重要影响因素。为研究新建地铁隧道在岩溶地层中开挖时，列车荷载对隧道、地表及地层的动位移和动应力响应，以贵阳地铁3号线下穿川黔铁路为背景，通过有限元软件建模计算了在最不利围岩和列车动载条件下，隧道拱顶无溶洞、有溶洞和溶洞注浆三种工况的动力响应规律进行对比分析。结果表明：在列车动荷载作用下，溶洞存在及对其注浆加固对地表位移动力响应的影响范围大致为3.3倍洞径以内，有溶洞时地表最大瞬时沉降发生在路基中线与隧道中线交叉处，为2.74 mm，而对其注浆加固后此处的沉降为2.16 mm，减小了21.2%；对溶洞进行注浆加固后隧道支护结构产生了相对更大动力响应，最大瞬时位移和主应力均发生在隧道拱顶，分别为-1.41 mm和-0.36 MPa；地层竖向应力从地表到隧道拱顶衰减最明显的是有溶洞的情况，从-0.0766 MPa 衰减到-0.0084 MPa，衰减率为89.03%。可见，对铁路与隧道之间的地层溶洞注浆加固后，在保证新建隧道安全的情况下，明显改善降低了列车动载引起的地表瞬时沉降。
In karst areas, train vibration load has become an important factor that causes surface karst collapse around railway. In order to study the dynamic displacement and stress response of train load to tunnel, ground and stratum when a new subway tunnel is excavated in karst stratum, taking Guiyang Metro Line 3 crossing Sicuan-Guizhou Railway as the background, the finite element software modeling is used to calculate under the most unfavorable conditions of surrounding rock and train dynamic load. The dynamic response rules of three conditions of no cave above the tunnel, with cave and cave grouting are compared and analyzed. The results show that: Under the action of train dynamic load, the influence range of the karst cave and grouting reinforcement on the surface displacement dynamic response is roughly within 3.3 times the diameter of the karst cave. Moreover, when there is a karst cave under the railway subgrade, the maximum instantaneous settlement of the surface occurs at the intersection between the middle line of the subgrade and the middle line of the tunnel, which is 2.74mm. After grouting reinforcement of the karst cave, the settlement here is 2.16mm，decreased by 21.2 percent. In addition, the maximum instantaneous displacement and principal stress, which are -1.41mm and -0.36MPa, occur in the tunnel vault. When there are karst caves in the stratum, the vertical stress attenuation from the surface to the tunnel vault is the most obvious, from -0.0766 MPa to -0.0084 MPa, with a attenuation rate of 89.03%. It can be seen that the ground instantaneous settlement caused by train dynamic load can be significantly improved and reduced under the condition of ensuring the safety of the new tunnel after grouting reinforcement of the karst cave between the railway and the tunnel.
杜碧涛,刘远明,陈会宇,等. 岩溶区铁路列车荷载对新建下穿隧道动力响应规律[J]. 科学技术与工程, 2023, 23(30): 13134-13142.
Du Bitao, Liu Yuanming, Chen Huiyu, et al. Study on Dynamic Response Law of Railway Train Load to New Tunnel under Railway in Karst Area[J]. Science Technology and Engineering,2023,23(30):13134-13142.