相对于直线隧道,小半径曲线隧道进行盾构掘进施工引起的地表沉降变形更为复杂,现有经验公式无法对其变形规律进行较好地拟合。基于中原地区某地铁出入场线的盾构隧道工程,根据相似原理建立砂土中盾构隧道沿曲线掘进施工的室内试验模型,开展了相似模型试验研究小半径曲线隧道盾构施工所引起的地表变形规律。试验充分考虑盾构在小半径曲线隧道的内侧超挖量,对盾构轴线和监测点坐标进行了修正,并通过与工程实测数据对比分析,验证了室内模型试验的合理性。结果表明:小半径曲线隧道盾构掘进施工引起的地表沉降峰值位置会向曲线内侧偏移,而地表隆起峰值随着曲率半径的减小而增大;地表变形曲线可采用双侧高斯曲线进行拟合,拟合得到的沉降峰值、沉降槽左侧和右侧宽度系数可用于修正小半径工况下的Peck经验公式,并能比较准确地预测和评估盾构在小半径曲线段掘进引起的地表变形;曲线外侧的地表隆起峰值和沉降峰值均随着隧道埋深的增加而减小。研究结果对小半径曲线隧道盾构掘进施工引起的地表变形预测有借鉴意义。
Compared with the straight tunnel, the surface settlement induced by shield tunneling in a small radius curve tunnel is more complex, and the existing empirical formula can not fit the deformation law well. Based on the shield tunneling project of one subway in Central China, a laboratory model of shield tunneling along a curve in sands is established according to the similarity principle, and then similar model tests are carried out to study the law of surface deformation caused by shield tunneling of a small radius curve tunnel. In the test, the shield axis and the coordinates of monitoring points are modified considering the overbreak of the shield at the inner side of the small radius curved tunnel. The rationality of the indoor model test is verified by comparing it with the measured data of the project. The results show that: The Peak value of the surface settlement will shift to the inside of the curve, and the surface heave increases with the decrease of radius of curvature; The surface deformation can be fitted using bilateral Gaussian curves, the Peak value of settlement and width coefficients of the left and right side of the settlement trough obtained by Gauss fitting curve can be used to modify the Peck empirical formula under the condition of small radius, and they can accurately predict and evaluate the surface deformation caused by shield tunneling in the curve section of small radius; The Peak value of uplift outside the curve and the Peak value of surface settlement caused by tunneling decrease with the increase of tunnel burial depth. The research results have some reference significance for the prediction of surface deformation caused by the construction of small-radius curved tunnels in actual projects, and can be used to guide the design and construction of curved tunnels.
[1] 张治国, 陈杰, 朱正国, 等. 考虑盾构铰接作用的小半径曲线隧道开挖诱发地层沉降分析[J]. 岩土力学, 2023, 44(4): 1165-1178.
[2] 赵秀绍, 魏度强, 于万友, 等. 小曲线半径盾构隧道上穿既有隧道影响分析[J]. 地下空间与工程学报, 2021, 17(4): 1216-1224.
[3] 张丽丽, 单琳, 郭飞, 等. 小曲线半径叠落盾构隧道近接施工安全控制研究[J]. 现代隧道技术, 2022, 59(3): 254-264.
[4] 孙捷城, 路林海, 王国富, 等. 小半径曲线盾构隧道掘进施工地表变形计算[J]. 中国铁道科学, 2019, 40(5): 63-72.
[5] 邓皇适, 傅鹤林, 史越. 小转弯半径曲线盾构隧道开挖引发地表沉降计算[J]. 岩土工程学报, 2021, 43(1):165-173.
[6] 孙厚强, 吴俊, 杜禹, 等. 考虑注浆压力非均匀分布的小半径曲线盾构掘进诱发地表沉降计算[J]. 广西大学学报(自然科学版), 2023, 48(5): 1051-1060.
[7] 赵翌川, 颜建平, 张晨光, 等. 小半径曲线盾构隧道施工的地层扰动规律研究[J]. 现代隧道技术, 2022, 59(增1): 243-250.
[8] 吴迪, 蒋敏敏, 肖昭然. 小半径曲线盾构施工对周边土体位移的影响[J]. 辽宁工程技术大学学报(自然科学版), 2021, 40(4): 318-326.
[9] 陈晨, 朱新健, 王永, 等. 小半径曲线段盾构隧道掘进过程中地表变形规律[J]. 铁道建筑, 2023, 63(10): 92-96.
[10] 金大龙, 李兴高. 砂土地层盾构隧道开挖面支护压力与地表变形关系模型试验研究[J]. 现代隧道技术, 2015, 52(2): 44-51.
[11] 武文安, 黄晓康, 卢坤林, 等. 合肥盾构地表沉降和土压力变化模型试验[J]. 防灾减灾工程学报, 2017, 37(6): 916-922.
[12] 宫志群, 徐吉祥, 李阳, 等. 盾构隧道开挖引起围土变形模型试验研究[J]. 地下空间与工程学报, 2020, 16(增2): 546-553.
[13] 房倩, 杜建明, 王中举, 等. 盾构施工影响下砂土地层变形规律模型试验研究[J]. 中国公路学报, 2021, 34(5): 135-143.
[14] 张晏铭, 刘庭金, 朱超, 等. 超载作用下土岩复合地层盾构隧道变形及破坏特征模型试验研究[J]. 铁道科学与工程学报, 2023, 20(11): 4277-4287.
[15] 刘勇, 周怡晟, 索晓明, 等. 盾构下穿高铁路基变形规律模型试验研究[J]. 岩土力学, 2023, 44(4): 941-951.
[16] 李铁才, 李西峙. 相似性和相似原理[M]. 哈尔滨: 哈尔滨工业大学出版社, 2014.
[17] 路林海, 孙捷城, 周国锋, 等. 黏性土地层曲线盾构施工地表沉降预测研究[J]. 铁道工程学报, 2018, 35(5): 99-105.
[18] Sigl O, Atzl G. Design of bored tunnel linings for Singapore MRT North East Line C706[J]. Tunnelling and Underground Space Technology, 1999, 14(4): 481-490.
[19] Peck, R B. Deep excavation and tunneling in soft ground[A] // Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineering[C]. Mexico City, Mexico, 1969, 266-290.
[20] 赵秀绍, 魏度强, 于万友, 等. 小曲线半径盾构隧道上穿既有隧道影响分析[J]. 地下空间与工程学报, 2021, 17(4): 1216-1224.
[21] 吴锋波, 郑卫强, 齐剑峰, 等. 地铁双线盾构区间地表横向沉降槽参数分析[J]. 地下空间与工程学报, 2021, 17(5): 1653-1663
