研究目的: 路基修建过程中倾斜跨越对地下坎儿井暗渠的扰动会引起暗渠不同的破坏模式。因此,需要明确既有坎儿井暗渠在新建高速铁路路基工程下的响应,通过三维数值模拟,进行斜交的路基工程荷载-地基土-坎儿井暗渠相互作用的研究,确定不同交角对应的高铁斜跨坎儿井的稳定临界深度。
研究结论: (1)由于线路与已有坎儿井暗渠的斜交,既有坎儿井暗渠在上覆路基跨越时,路基面会出现不均匀沉降;(2)随着暗渠与线路的交角增大,塑性区范围减小,暗渠周围剪切应变变小,坎儿井地基暗渠临界深度的评判标准能较好地用于评价交角对高铁斜跨坎儿井的稳定性的影响;(3)结合临界深度评判标准,得到了坎儿井暗渠在未支护时稳定临界深度变化规律,即当暗渠与路基交角分别为0°、30°、60°和90°时,坎儿井暗渠临界深度分别为14 m、13 m、8 m和7 m;(4)本研究成果可为坎儿井地区高速铁路设计提供技术参考。

Research purposes: During the construction of the subgrade engineering, the disturbance of the underground qanat culvert by the inclined crossing can cause different damage patterns in the culvert. Therefore, it is necessary to clarify the response of existing qanat culverts under the new high-speed subgrade engineering, to carry out the study of the subgrade engineering load-foundation soil-qanat culvert interaction through three-dimensional numerical simulation, and to determine the stability critical depth corresponding to different intersection angles.
Research conclusions: (1) Due to the oblique intersection between the railway and the existing qanat culvert, when the existing qanat culvert crosses over the overlying subgrade, the subgrade surface will experience uneven settlement. (2) The larger the intersection angle between the culvert and the railway, the smaller the range of plastic zone, the smaller the shear strain around the culvert. The criteria for evaluating the critical depth of the qanat culvert can be better used to evaluate the intersection angle to the stability of the high-speed railway embankment oblique crossing qanat. (3) Combining the critical depth evaluation criteria, the stable critical depth change rule of the qanat culvert without support is obtained, that is, when the intersection angle is 0°, 30°, 60° and 90°, the critical depth of the qanat culvert is 14 m, 13 m, 8 m and 7 m. (4) The research results can provide a technical reference for the design of high-speed railways in the qanat region.